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InternetworkingIndonesiaJournal
Volum
e 2N
umber 2
Fall 2010
ISSN: 1942-9703IIJ ©
2010w
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.InternetworkingIndonesia.org
Editors’ Introduction 1
The Effect of IPv6 Packet Size on the Implementation 3of CRC Extension Headerby Supriyanto, Iznan H. Hasbullah & Rahmat Budiarto
A Modified Weighted Clustering Algorithm for Stable Clustering 9using Mobility Prediction Schemeby S. Muthuramalingam, R. Viveka, B. Steffi Diana & R. Rajaram
Mengamankan Single Identity Number (SIN) Menggunakan QR Code 17dan Sidik Jariby Fridh Zurriyadi Ridwan, Hariyo Santoso & Wiseto Agung
EnsoTracker: Mouse Controller Device using Head Movement 21by Gunawan, Tri Kurniawan Wijaya, Indra Maryati & Edwin Seno Dwihapsoro
UTAUT Model for Understanding Learning Management System 27by I Gusti Nyoman Sedana & St. Wisnu Wijaya
The Indonesian Journal of ICT and Internet Development
Star Schema Design for Concept Hierarchy in Attribute Oriented Induction 33by Spits Warnars
Internetworking Indonesia JournalThe Indonesian Journal of ICT and Internet Development
ISSN: 1942-9703
Manuscript Language: The Internetworking Indonesia Journal accepts and publishes papers in Bahasa Indonesia and English.
Manuscript Submission: Manuscripts should be submitted according to the IEEE Guide for authors, and will be refereed in the standard way. •Manuscript pages should not exceed 7 pages of the IEEE 2-column format. It should be submitted as a Microsoft-Word file, •using the IIJ Template document which can be found at the www.InternetworkingIndonesia.org website.Manuscripts submitted to the IIJ must not have been previously published or committed to another publisher under a copy-•right transfer agreement, and must not be under consideration by another journal.Papers previously published at conferences can be submitted to the IIJ, but must be revised so that it has significant differences •from the conference version.Authors of accepted papers are responsible for the Camera Ready Copy formatted using the same IIJ Template format.•Authors are advised that no revisions of the manuscript can be made after acceptance by the Editor for publication. The ben-•efits of this procedure are many, with speed and accuracy being the most obvious. Please email your papers (or questions) to: • [email protected]
Submission Guidelines: Please review the descriptions below and identify the submission type best suited to your paper.Research Papers• : Research papers report on results emanating from research projects, both theoretical and practical in nature.Short papers• : Short research papers provide an introduction to new developments or advances regarding on-going work.Policy Viewpoints• : Policy Viewpoints explore competing perspectives in the Indonesian policy debate that are informed by aca-demic research.Teaching Innovation• : Teaching Innovation papers explore creative uses of information technology tools and the Internet to im-prove learning and education in Indonesia.Book Reviews• : A review of a book, or other book-length document, such as a government report or foundation report.
Prof. Edy Tri Baskoro, PhD (ITB, Indonesia)Mark Baugher, MA (Cisco Systems, USA) Lakshminath Dondeti, PhD (Qualcomm, USA)Paul England, PhD (Microsoft Research, USA)Prof. Svein Knapskog, PhD (NTNU, Norway) Prof. Merlyna Lim, PhD (Arizona State University, USA)
Prof. Bambang Parmanto, PhD (University of Pittsburgh, USA) Prof. Wishnu Prasetya, PhD (Utrecht University, The Netherlands)Graeme Proudler, PhD (HP Laboratories, UK) Prof. Jennifer Seberry, PhD (University of Wollongong, Australia) Prof. Willy Susilo, PhD (University of Wollongong, Australia)Prof. David Taniar, PhD (Monash University, Australia)
Thomas Hardjono, PhD (MIT Kerberos Consortium, MIT, USA)
Budi Rahardjo, PhD (ITB, Indonesia)
Kuncoro Wastuwibowo, MSc(PT. Telkom, Indonesia)
Internetworking Indonesia Journal is a semi-annual peer-reviewed electronic journal devoted to the timely study of Information & Com-munication Technology (ICT) and Internet development in Indonesia. The journal follows the open-access philosophy and seeks high-quality manuscripts on the challenges and opportunities presented by information technology and the Internet in Indonesia.
Editorial Advisory Board
Co-Editors
Journal mailing address: Internetworking Indonesia Journal, PO Box 397110 MIT Station, Cambridge, MA 02139, USA.
Technical Editorial Board
Sulfikar Amir, PhD (NTU, Singapore)Moch Arif Bijaksana, MSc (IT Telkom, Indonesia)Teddy Surya Gunawan, PhD (IIUM, Malaysia)Dwi Handoko, PhD (BPPT, Indonesia)Mira Kartiwi, PhD (IIUM, Malaysia)Bobby Nazief, PhD (UI, Indonesia)Anto Satriyo Nugroho, PhD (BPPT, Indonesia)
Yanuar Nugroho, PhD (Manchester University, UK)Bernardi Pranggono, PhD (University of Leeds, UK)Bambang Prastowo, PhD (UGM, Indonesia)Bambang Riyanto, PhD (ITB, Indonesia)Andriyan Bayu Suksmono, PhD (ITB, Indonesia)Henri Uranus, PhD (UPH, Indonesia)Setiadi Yazid, PhD (UI, Indonesia)
Vol. 2/No. 2 (2010) INTERNETWORKING INDONESIA JOURNAL 1
ISSN: 1942-9703 / © 2010 IIJ
ELCOME to the Fall/Winter 2010 issue of the
Internetworking Indonesia Journal. We are pleased to
bring you this regular issue of the IIJ which contains a broad
range of papers, include those written by graduate students. As
described in the goals of the IIJ, among others the journal
seeks to be a publishing venue for graduate students (such as
Masters/S2 and PhD/S3 students) as well as working
academics in the broad field of ICT and Internet development.
This includes graduate students from Indonesian universities
and those studying abroad.
Consistent with another goal of the IIJ, the current issue of
the journal has papers written in Bahasa Indonesia. From the
outset the IIJ has sought to promote the culture of writing and
of excellent authorship in Indonesia. It is for this reason that
the IIJ is “bilingual” in that it accepts and publishes papers in
both English and Bahasa Indonesia. We believe that by
publishing papers in Bahasa Indonesia, we provide students
and other authors the opportunity to develop formal writing
skills for technical papers in Bahasa Indonesia.
The first paper in the current issue deals with the use of a
cyclic redundancy check code (CRC code) in the extension
header of an IPv6 packet. The paper proposes the introduction
of a new IPv6 header extension whose contents would be a
CRC code computed over the relevant fields of the packet.
One aim of this approach is to obviate the need for error
detection at the underlying Data Link layer of the intermediate
nodes. The paper reports a number of results from tests using a
simple IP network topology. Although introducing this new
extension header costs additional computation at the sender
and receiver, the authors claim that overall benefits is derived
by from the intermediate nodes (routers) not needing to
perform error detection at their Data Link layer prior to
routing/forwarding packets.
Mobile ad hoc networks (MANET) is the topic of the
second paper. More specifically, the paper deals with the issue
of cluster-head selection in a stable manner. The dynamic
nature of the members of a wireless ad hoc network poses a
number of interesting questions, including that of reliable
routing. With each node in an ad hoc network acting also as
wireless router, the nodes need to have the ability to self-
organize into a given network architecture, such as a cluster
network architecture. This in-turn necessitates the selection of
certain nodes to become cluster-heads. This paper proposes a
new approach to the selection of such cluster-heads. The
approach is based on the well-known weighted clustering
algorithm (WCA), and introduces a mobility prediction
scheme which looks not only at the mobility of a given node
The editors can be reached individually at the following email addresses.
Thomas Hardjono is at [email protected], Budi Rahardjo is at
[email protected], while Kuncoro Wastuwibowo is at
but also at the relative mobility of its neighbors. The
prediction algorithm uses the node link expiration time as the
basis for the prediction scheme.
The third paper, written in Bahasa Indonesia, focuses on the
security issues around the planned use (by the Indonesian
government) of the 16-digit Single identity Number (SIN) for
every resident of Indonesia. The aim of the SIN is, among
others, to expedite access by residents to government services
by replacing non-digital credentials and other identity
documents. The paper looks at the possible use of a two-
dimensional bar code called the Quick Response (QR) code to
conveniently represent the SIN. This barcode would then be
easily readable (eg. at local government offices) by using
code-reader devices that are attachable to PC computers or
mobile phones. The paper also considers the use of biometric
scans to authenticate the user as the legitimate holder of a
given SIN. Finally, the paper offers some broad suggestions
regarding the implementation of such a SIN-based system,
including the creation of the SIN values and its associated
card, and the verification of the card and SIN at the point of
service.
Providing affordable computer-accessibility to sufferers of
quadriplegia is the topic of the fourth paper. For handicapped
persons in developing nations, the cost of devices and related
equipment represents a major issue. As such, this paper looks
into the possible development of affordable devices using
cheap off-the-shelf components. The particular device in this
case is a mouse controller, which can be operated by detecting
the user’s head movement.
The fifth paper, which is also written in Bahasa Indonesia,
addresses quite a different topic from the previous papers,
namely that of a learning management system. Following the
unified theory of acceptance and use of technology, the paper
reports some research results from experiments conducted at
the Sanata Dharma University using the Exelsa system. The
research found that performance expectancy, social influence
and facilitating conditions represented significant factors
influencing the behavioral intention of the students employing
the Exelsa system.
The last paper is one written by a graduate student on the
topic attribute oriented induction and its influence in the
design of databases within data mining. The paper provides an
illustration of the steps required to arrive at database tables
from concept hierarchies as the point of departure. The paper
provides a basic algorithm to convert a non-rule based concept
hierarchy into database tables.
Thomas Hardjono
Budi Rahardjo
Kuncoro Wastuwibowo
Editors’ Introduction
W
2 INTERNETWORKING INDONESIA JOURNAL Vol. 2/No. 2 (2010)
ISSN: 1942-9703 / © 2010 IIJ
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 3
ISSN: 1942-9703 / © 2010 IIJ
Abstract—The traditional TCP/IP stack requires verification
and regeneration of the CRC code in every router to detect
transmission errors. For IPv6 packet transmission over high
speed networks, this task is redundant because of the very rare
transmission error and thus introduces unnecessary latency. The
CRC Extension Header (CEH) was proposed to eliminate the
unnecessary duplication of error detection. Since IPv6 packets
are transmitted over Ethernet, the packet size ranges from 1280
up to 1500 bytes. In the near future, the size will increase with the
advance of underlying technology such as 100 Gigabit Ethernet.
This paper studies the effect of various IPv6 packet sizes with the
implementation of CEH on the processing time and network
latency. Experiments were done by transmitting various IPv6
packet sizes over high speed networks. The results showed that
higher packet sizes increases processing time and network
latency.
Index Terms—Routing, TCP/IP, IPv6, error correction.
I. INTRODUCTION
OUTERS in a computer network have the important role
in the packet forwarding process in order to ensure that
each packet reaches its correct destination. An IPv6 packet
transmitted through the Internet has to pass through many
routers along the network. A router can be defined as three of
the five layers of the TCP/IP stack, namely the Physical layer,
the Data Link layer and the Network layer. In general, a router
needs to decide to which node a packet has to be forwarded
next after the IPv6 header processing are done. The decision is
made in the Network layer of the router. However, before the
packet reaches the Network layer, it must pass through the
error detection process in the Data Link layer. The Data Link
layer always verifies the CRC code attached with the frame
received to ensure that the frame from the previous hop is free
from transmission error. Only the correct frame will be
Manuscript received October 26, 2010. This work was supported by the
Ministry of National Education of the Republic of Indonesia.
Supriyanto is with the Electrical Engineering Department, University of
Sultan Ageng Tirtayasa, Cilegon, Banten, Indonesia (e-mail: supriyanto@ ft-
untirta.ac.id).
Iznan H. Hasbullah is with the National IPv6 Centre (NAv6) Universiti
Sains Malaysia, Penang, Malaysia. (e-mail: [email protected]).
Rahmat Budiarto is with the School of Computer Sciences, Universiti
Sains Malaysia, Penang, Malaysia (e-mail: [email protected]).
delivered up to the Network layer for forwarding and hop limit
updating.
The Network layer within a router on an IPv6 network does
a simpler task compared to the network layer of a IPv4 router.
In an IPv6 router there are no error detection processing
(header checksum checking) and fragmentation. In addition,
the size of an IPv6 header is fixed. This means that IPv6
packets are processed faster on router. However, the Data Link
layer of the router not only needs to perform CRC calculation
for the received frame but also for each frame that needs to be
forwarded to the next hop. On a large network that with
numerous routers this double CRC calculation will be repeated
in every router, as shown in Figure 1.
Figure 1: CRC Code Generation and Verification
Figure 1 shows a small network with three routers as
intermediate nodes. In this network, there will be eight CRC
calculations: four CRC code generations and four CRC code
verifications. For IPv6 packet transmission over high speed
networks which has an extremely small probability of
transmission error, those repeated tasks are unnecessary. This
is more so in the case of a reliable medium such as fiber optic
which is not influenced by either the magnetic field or electric
field. Errors within this kind of medium will be infinitesimal
that practically we can say it has a near zero probability of
occurring.
The IPv6 protocol has been designed with features that
provide better performance than the former IPv4 protocol,
The Effect of IPv6 Packet Size on
Implementation of CRC Extension Header
Supriyanto
Electrical Engineering Department
University of Sultan Ageng
Tirtayasa (UNTIRTA) Indonesia
Iznan H. Hasbullah
National Advanced IPv6 Centre Universiti Sains Malaysia
(USM) Malaysia
Rahmat Budiarto
School of Computer Sciences Universiti Sains Malaysia
(USM) Malaysia
R
4 INTERNETWORKING INDONESIA JOURNAL SUPRIYANTO ET AL.
ISSN: 1942-9703 / © 2010 IIJ
including the extensibility of IPv6 extension header. IPv6
allows the definition of a new extension header in the future
without impacting the existing infrastructure. In this paper we
propose a CRC Extension Header (CEH) as a new IPv6
extension to perform error control within the Network layer
and eliminating error control from Data Link layer [1]. In the
near future, the IPv6 packet size will be increased [2].
Implementation of a CEH for a larger packet size is still
debatable. This paper attempts to understand the effect of
varying IPv6 packet sizes on the implementation the IPv6
packet transmission over high speed networks.
II. OVERVIEW OF CRC EXTENSION HEADER
The CEH is a new extension header that is proposed to
reduce the bottleneck in IPv6 packet transmission over high
speed networks by eliminating the CRC verification and
regeneration in each and every router, as shown in Figure 1.
This idea is entirely different from the existing method that
conducts error detection and correction in the Data Link layer
of a router. This new mechanism does not require the Data
Link layer to verify and regenerate the CRC code for error
detection. However, the concept of CEH does not eliminate
overall CRC code generation and verification during IPv6
packet transmission. Generation of CRC code is done in the
sender’s machine while the verification of CRC code will be
done at Network layer of the destination node by processing
the CEH inside the received IPv6 packet. Routers are only
required to process IPv6 packet at their Network layer in the
usual manner, which consists simply of a forwarding decision
and hop limit updating.
There are three major rationales of the idea of the CEH:
Firstly, we would like to optimally utilize one of the
advantages of IPv6 features, specifically the IPv6 extension
header. IPv6 offers the opportunity to develop new extension
headers for IPv6 packet transmission improvement in the
future. Furthermore, it is not limited to 40 bytes only. In
addition, applying a new extension header within an existing
network will not disturb current IPv6 network operations.
Secondly, within new high speed networks medium — such as
fiber optic — the probability of transmission errors occurring
is very small. This allows the error detection function in
higher layer to be bypassed. Thus, the duplication of CRC
calculation could be eliminated from the Data Link layer.
Thirdly, the high transfer rate of current underlying
technology, especially gigabit Ethernet, allows the
transmission rates of more than 100 Gbps. Eliminating the
error detection process in the intermediate nodes will decrease
round trip delay from the sender to receiver. Hence, low
latency of IPv6 packet transmission over high speed networks
could be achieved.
Since all the existing extension headers already have
specific functions, designing a CEH cannot make use of any
existing extension header. Therefore we need to define a new
one. The aim is to still utilize the advantages of the current
error control but at the same time avoid its weaknesses. The
approach uses the widely deployed CRC-32 error detection
mechanism to detect transmission errors. To obtain an optimal
result, we select an appropriate generator polynomial to be
implemented in the CEH [3]. In terms of error correction, the
CEH applies retransmission procedure to overcome erroneous
packets, such as Automatic Repeat reQuest (ARQ). Details of
the CEH format and mechanism design will be presented in
the next section.
A. Format of IPv6 with CEH
Currently, there is no standard format for IPv6 extension
headers. The existing IPv6 extension headers have different
formats compared to one another. Thus, the format of the CEH
follows the draft of the generic IPv6 extension header (GIEH)
proposed in [4]. The CEH is placed after the destination
address field of the IPv6 header, as shown in Figure 2. It has
three main fields: the Next Header field, the Reserved field
and CRC-32 code field. The next header is an 8-bit indicator
to point to other extension headers following the CEH or
upper layer data. As a new extension header, the CEH has not
obtained specific number from Internet Assigned Numbers
Authority (IANA). The Reserved field is allocated for future
use instead of specific extension header type. The CRC-32
code field is the important field for the CEH. It contains the
CRC code generated by the sender machine. This code is used
only by the destination node for verification.
Figure 2: IPv6 Packet with CRC Extension Header
B. CEH Generation
The CRC-32 code field is the most important field of the
CEH. CEH generation is determined by CRC-32 code
generation. The code is generated from entire IPv6 packet
excluding hop limit field. The CRC-32 code generation
requires a generator polynomial [5]. The generator polynomial
used in the CEH was selected from three candidates, namely
the generator polynomial standardized in IEEE802.3 [6], the
generator polynomial proposed by Guy Castagnoli [7] and the
generator polynomial proposed by Philip Koopman [8]. The
test conducted showed that Castagnoli’s CRC-32C is the most
suitable generator polynomial implement for the CEH [3].
The generation process of the CRC-32 code follows the
usual algorithm used in the Data Link layer, which is already
adapted for the Network layer as shown in Figure 3 [3]. The
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sender generates a CRC-32 code and then inserts the code into
the CRC-32 code field of the CEH. When the CEH is created
in an IPv6 packet, the extension header field is first initialized
to zero except for the next header field. A complete IPv6
packet includes a main header with next header value
indicating the type of CEH, an extension header which is CEH
and a payload. The packet is now ready for transmission along
the network path until it reaches its destination.
Figure 3: CEH Generation
C. CEH Verification
The verification of CEH will be done at the final destination
by following the algorithm depicted in Figure 4 [3]. Once the
receiver receives an IPv6 packet from previous node, it will
check the next header field of the packet. When the value
indicates there is a CEH inside the packet, it extracts the CEH
and generates a new CRC-32 code from the entire IPv6 packet
(omitting the hop limit field). The CRC-32 code generated by
the receiver will be compared to the CRC-32 code found
inside the IPv6 packet, which is located within the CRC-32
code field of the CRC extension header. If both CRC-32 code
the same, then there is no transmission error in the IPv6 packet
received. The receiver then forwards the packet into higher
layer. Otherwise it will discard the packet and wait for
retransmission.
Figure 4: CEH Verification
III. EXPERIMENTS
The CEH is a new concept for error detection for the entire
IPv6 packet which is done at the Network layer. To verify the
acceptability of the new concept we performed an experiment
using the network topology depicted in Figure 5. The
experiment has two scenarios: the transmission of IPv6
packets with the CEH for error detection in Network layer and
the transmission of IPv6 packets with Frame Check Sequence
(FCS) for error detection in Data Link layer. The first
experiment simulates the new concept, while the later
simulates the existing system. The two scenarios yielded an
adequate data to justify the performance gain of the new error
detection approach compared to the current error detection.
Figure 5: Network Topology for IPv6 Packet Transmission
The topology in Figure 5 has five nodes: Device 1 as a
sender, Router 1, Router 2, Router 3 and Device 2 are the
receivers. All nodes are PC computers equipped with Core 2
Duo processors that were configured as a mini IPv6 network.
The sender is an end system installed with an IPv6 packet
generator program written in JAVA that is able to generate
both IPv6 packet with the CEH and IPv6 packet without the
CEH. Router 1, 2 and 3 represent the intermediate system of
the network whose task is to forward the packets.
In the first experiment, the routers simply forwarded the
IPv6 packets with the CEH rather than checking each and
every packet for error detection. In the second experiment the
intermediate system performs error checking for each packet
before forwarding the packet to next node in the path. The last
node is the receiver which is a PC installed with the same
program as the sender to verify all packets received.
The sender generates an IPv6 packet by adding the IPv6
main header to a TCP segment received from the upper layer.
The Network layer then generates the CRC-32 code from both
the IPv6 header and the payload using algorithm in Figure 3.
The CRC code obtained is then inserted as the CRC extension
header into the IPv6 packet. In the first scenario the Data Link
layer just adds the link layer header. There is no trailer in the
Data Link layer frame that usually performs the error detection
task. The frame without frame check sequence (FCS)
generated by the sender is then transmitted through the
experiment network.
When the IPv6 packet reaches the intermediate nodes
(namely Router 1, 2 and 3) no CRC code calculation will be
performed by the routers for error detection. The ingress frame
is just verified for its frame header by the incoming port of
router and passed to the Network layer to determine the next
6 INTERNETWORKING INDONESIA JOURNAL SUPRIYANTO ET AL.
ISSN: 1942-9703 / © 2010 IIJ
path (forwarding process). The egress frame also does not
have a Data Link layer trailer. It simply obtains the link layer
header.
The only node that will verify the IPv6 packet is the
destination node (receiver), as indicated by destination address
field of the IPv6 packet. The verification follows algorithm in
Figure 4 to check whether the packet received is free from
error. Thus, the receiver node’s task is to receive the packet in
Data Link layer, release the Data Link layer header without
computing the CRC code, and then to deliver the packet to the
Network layer for verification.
In the second experiment which is a simulation of the
current error detection mechanism, the sender generates an
IPv6 packet without the extension header. The packet is then
encapsulated by Data Link layer by adding Data Link layer
header and trailer. We refer to this frame as the IPv6 packet
with FCS. Each intermediate node will receive the packet and
process it as usual. They process the Data Link layer header
including CRC code computation to detect transmission errors
for the corresponding hop. Only the packets that are verified
as free from error will be delivered up to Network layer for
forwarding process without processing any extension header.
Before the IPv6 packet is forwarded to the next hop, the
packet will be encapsulated again in Data Link layer of the
outgoing port of the router including CRC code regeneration.
The receiver node in the second experiment captures the IPv6
packet that was addressed to it and then verifies the packet for
error detection. The correct packet will be passed to Network
layer. Otherwise, it will discard the erroneous packet and wait
for retransmission.
In order to know the effects of IPv6 packet size with the
implementation of the CEH, we measure two main metrics:
processing time and error detection capability. Processing time
is the packet processing time in each node including the CRC-
32 code computation, packet generation and packet
verification. Here it is very important to know the network
latency, which is the most important aspect of network
performance with various packet sizes. With regards to error
detection capability, it is also important to know the new error
detection capabilities to detect transmission error on varying
sizes of IPv6 packets.
IV. RESULTS AND DISCUSSION
The sender’s processing time is the time required to
generate an IPv6 packet with the CEH using the algorithm in
Figure 3. While the receiver’s processing time is the time
required to verify the IPv6 packet received and the CEH
verification using the algorithm in Figure 4. Experiments of
IPv6 packets with the CEH, using varying packet sizes from
64 bytes to 1500 bytes yielded the results as shown in Table 1.
The table shows the relationship between the sender’s
processing time and packets size of the two error detection
mechanisms on TCP/IP, namely the transmission of IPv6
packets with the CEH as a proposed mechanism and the IPv6
packet transmission with FCS (existing system) as a
comparison. This is done to learn about the impact of packet
sizes on the performance of the two error detection
mechanisms.
Table 1: Correlation between Processing Time and Packet
Size at the Sender
Size 64 128 256 512 1024 1280 1492 Average
CEH 0.689 0.718 0.772 0.883 1.039 1.067 1.133 0.900
FCS 0.682 0.686 0.778 0.788 0.834 0.876 0.909 0.793 Δ 0.007 0.132 0.006 0.105 0.205 0.191 0.224 0.107
Both the IPv6 packet with CEH and the packet with FCS
require a certain amount of time to process at the sender as
well as at the receiver. The processing time of the packet at the
sender increases with the increase in packet size. This is
because CRC code generation was done byte-per-byte of the
packet. Thus more bits in a packet means longer time to
perform processing of the IPv6 packet. Table 1 also shows that
the average of processing time for all packet sizes for the
transmission of IPv6 packet with CEH is 13.5% higher than
the transmission of IPv6 packet with FCS. This is due to the
fact that the IPv6 packet with CEH generation at the Network
layer (shown in Figure 3) is more complex compared to FCS
generation at the Data Link layer. The process to generate the
CRC code from the whole IPv6 packet requires firstly the
exclusion of the hop limit and then secondly the insertion of
the CRC code as the extension header. In contrast the FCS
generation simply divides the whole frame with the generator
polynomial and followed by appending the CRC code in the
last part of the frame.
Similar to the sender, the receiver’s processing time of the
IPv6 packet which is listed in Table 2 showed that the
processing time is affected by the packet size. The larger the
packet, the higher it’s processing time. On average the
receiver’s processing time of IPv6 packet transmission with
CEH is 16.3% higher than IPv6 packet transmission with FCS.
Note that the percentage value is higher than in the sender.
This is because the average processing time for both IPv6 with
CEH and IPv6 with FCS at the receiver is less. In other words,
the processing time of IPv6 packet at the receiver is faster than
at the sender.
Table 2: Correlation between Processing Time and Packet
Size at the Receiver
Size 64 128 256 512 1024 1280 1492 Average
CEH 0.568 0.568 0.583 0.600 0.642 0.662 0.670 0.613
FCS 0.495 0.491 0.512 0.514 0.548 0.566 0.565 0.527
Δ 0.073 0.077 0.071 0.086 0.094 0.096 0.085 0.086
The processing times of IPv6 packets with the CEH as
listed in Table 1 and Table 2 is based on the algorithm in
Figure 3 and Figure 4. Even though the process of generating
the CEH at the sender and at the receiver is similar, the sender
has to generate the IPv6 packet first before it can generate the
CEH. In contrast the receiver simply has to receive IPv6
packets without needing to generate any packets.
However, note that the transmission of IPv6 packets
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exploiting the CEH as an error detection method in the
Network layer has eliminated the need for CRC code
calculation and regeneration in every router. This resulted in
the faster processing of IPv6 packets in every router in the
network, where a router only processes the packets at the
Network layer (routing and forwarding). Hence, although
processing time at the end systems (sender and receiver) is
higher, the total network latency of IPv6 with CEH
transmission is visibly lower than IPv6 with FCS. Figure 6
shows the correlation between network latency in milliseconds
(ms) and packet sizes in bytes. In the figure, network latency
of the IPv6 packet with CEH transmission is 68 % lower than
IPv6 with FCS. The network latency as shown in Figure 6
increases when the packet size increases. Compared to FCS,
the increasing network latency of IPv6 with the CEH is lower
as shown by the two graphs in Figure 6.
Figure 6: Network Latency
Another measurement is the error detection capability. Error
detection capability of an error control mechanism is the
ability to catch transmission errors during transmission from
the sender to the receiver. Recent high speed network
technologies have made the occurrence of transmission errors
very rare. Employing more error detection tools is inefficient
and also redundant. However, we cannot eliminate the tools
entirely because if an error occurred during the
communications then data will be corrupted. Proposing to
exploit the CEH as an error detection tool is the correct way. It
can reduce the redundant error control process but at the same
time it does not ignore the error.
Error is unpredictable. Thus an error control mechanism
should be able to detect the error inside the packet transmitted
and correct it. In order to know ability of CEH to detect
transmission errors, we send erroneous IPv6 packet with the
CEH. The result illustrated that all erroneous IPv6 packets
sent are successfully detected by the receiver.
V. CONCLUSION
In this paper we have proposed a new concept of handling
transmission errors by exploiting the IPv6 extension header.
The new concept utilizes the CRC extension header (CEH) as
an error control method at the Network layer and eliminates
error control at the Data Link layer of the intermediate nodes.
Typically, the extension header is generated by the sender and
is processed by the receiver. Thus, the CEH that contains the
CRC code is also processed by the receiver.
Using the CEH as a new IPv6 extension header for error
detection at the Network layer increases the processing time of
IPv6 packets both at the sender and at the receiver. The
increase in processing time is influenced by the packet size.
The higher the packet size the longer it will take to process the
packet. However, our proposed new concept has eliminated
error detection routine at the Data Link layer.
Elimination of error detection at the Data Link layer means
eliminating CRC code computation and regeneration in each
and every router. This reduces the total network latency on
IPv6 packet transmission. The results show that overall
network latency decrease by 68% compared with normal
latency. It also reduces the Data Link layer frame size due to
the elimination of 4 bytes of frame check sequence field. The
proposed error control mechanism also shows good ability to
detect transmission error inside the transmitted packet. The
experiment showed that all IPv6 packets sent with errors are
successfully detected by the receiver.
REFERENCES
[1] Supriyanto, Raja Kumar Murugesan, Rahmat Budiarto, Sureswaran Ramadass, CRC Extension Header (CEH): A New Model to Handle
Transmission Error for IPv6 Packets over Fiber Optic Links, Proceedings of IEEE Symposium on Industrial Electronics and
Applications (ISIEA 2009), October 4-6, 2009, pp. 569 – 573.
[2] Supriyanto, Iznan H. Hasbullah, Rahmat Budiarto, Exploiting IPv6 Extension Header to Handle Transmission Error for IPv6 Packets Over
High Speed Networks, Proceedings of International Conference on Advanced Computer Science and Information System, 7 – 8 December
2009.
[3] Supriyanto, Abidah M. Taib, Rahmat Budiarto. Selecting a Cyclic
Redundancy Check (CRC) Generator Polynomial for CEH (CRC Extension Header), Proceedings of International Conference on Quality
in Research, Jakarta. 3 – 6 August 2009, ISSN 114-1284 pp. 245 – 250
[4] S. Krishnan, et. al, An uniform format for IPv6 extension headers, Internet Draft IETF, 2008. http://ietfreport.isoc.org/idref/draft-krishnan-
ipv6-exthdr/
[5] A.S. Tanenbaum, Computer Networks, Fourth Edition, Prentice Hall of India. New Delhi, 2006.
[6] ANSI/IEEE Standard for Local Area Networks, Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and
Physical Layer Specifications. 1984. http://standards.ieee.org/getieee802/802.3.html.
[7] Castagnoli, G., Brauer, S. & Herrmann, M. Optimization of cyclic
redundancy-check codes with 24 and 32 parity bits. IEEE Transactions on Communications, 1993, pp. 883-892.
[8] Koopman, P. 32-bit cyclic redundancy codes for Internet applications,
Proceedings. International Conference on Dependable Systems and Networks (DSN). 2002.
http://www.ece.cmu.edu/~koopman/networks/dsn02/dsn
8 INTERNETWORKING INDONESIA JOURNAL SUPRIYANTO ET AL.
ISSN: 1942-9703 / © 2010 IIJ
Supriyanto received the B.Eng. degree in
Electrical Engineering from Brawijaya University
Malang, Indonesia in 1999, and and M.Sc in
Computer Science from Universiti Sains Malaysia
(USM) in 2010. Currently, he is a lecturer and also
department secretary in the Electrical Engineering
Department at the University of Sultan Ageng
Tirtayasa (UNTIRTA). He is a researcher in the
Computer Network Laboratory at the university.
His research interest includes computer networks
especially, IPv6, IPTV over overlay network and
wireless communication.
Iznan H. Hasbullah graduated with the B.Sc
degree in electrical engineering in 1998 from
Rensselaer Polytechnic Institute, Troy, New York.
He is currently a Research Officer with National
Advanced IPv6 Centre (NAv6) at University Sains
Malaysia, Pulau Pinang. He is the Domain Head of
HD Video Conference for IPv6 group under Next
Generation Multimedia & Telemedicine Cluster at
NAv6. Prior to joining NAv6 in 2009, he was an
R&D Consultant with MLABS System Berhad
(MLABS) seconded to JMCS Sdn. Bhd. to
spearhead a project titled High Definition Video
Conferencing for IPv6 Networks. He held the post
of Chief Technology Officer (CTO) while with
JMCS Sdn. Bhd. He was involved in two network
security audit exercise commissioned by Malaysian
Communications and Multimedia Commission
(MCMC) in the year 2003 and 2004. He was also
part of a team that brought Advance Military
Mobile Conferencing System (AMMCS) to the
Maritime Langkawi International Maritime &
Aerospace Exhibition (LIMA'03) in 2003. His area
of expertise includes multimedia conferencing
application for computer supported cooperative
work (CSCW), software architecture, Graphical
User Interface (GUI), Component Object Modeling
(COM), Microsoft Foundation Classes (MFC) and
C++ Language.
Rahmat Budiarto received the B.Sc. degree from
Bandung Institute of Technology (ITB) in 1986,
and the M.Eng and Dr.Eng degree in Computer
Science from Nagoya Institute of Technology in
1995 and 1998 respectively. Currently, he is an
associate professor at the School of Computer
Sciences at the Universiti Sains Malaysia (USM) as
well as the advisor of Indonesia IPv6 Task Force.
His research interest includes IPv6, network
security and Intelligent Systems. He was chairman
of APAN security working group.
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 9
ISSN: 1942-9703 / © 2009 IIJ
Abstract—This paper proposes an idea for selecting stable
cluster heads using a modified Weighted Clustering Algorithm
and combining it with Link Expiration Time calculation. The
mobile ad hoc network consists of nodes that move freely and
communicate with each other. One way to support efficient
communication between nodes is to partition ad hoc networks
into clusters. Many clustering schemes have been proposed to
form clusters. The WCA has improved performance compared
with other previous clustering algorithms. However, the high
mobility of nodes will lead to high frequency of re-affiliation
which will increase the network overhead. To solve this problem,
we propose a time-based WCA which can enhance the stability of
cluster formation followed by stable cluster head selection. Then
duration of nodes that are alive is considered. Meanwhile for
forthcoming nodes the duration of link between them and the
Cluster head is calculated. This is the Link Expiration time and it
is calculated based on the three factors, namely position, speed
and direction of nodes. If the calculated link expiration time is
greater than the threshold value it is allowed to join the
respective cluster. This is done to form stable clusters and to
reduce the re-affiliation frequency.
Index Terms—Adhoc Networks, Stable clustering, Weighted
clustering algorithm, re affiliation, mobility prediction, link
expiration time.
I. INTRODUCTION
N recent years, the development in wireless communication,
and the widespread use of mobile and handheld devices, has
resulted in the increasing popularity of mobile ad hoc
networks (MANET). A mobile ad hoc network is a collection
of wireless mobile nodes that dynamically form a network
without the need for any pre-existing network infrastructure.
Every node in the network is serving as a router, which means
that every node is able to forward data to other nodes in the
same transmission range. When wireless nodes are in an area
that is not covered by any existing infrastructure, one of the
possible solutions to achieve the ubiquitous computing is to
enable wireless nodes to operate in the ad hoc mode and self-
organize themselves into cluster based network architecture.
S. Muthuramalingam can be reached at [email protected]. R. Viveka
can be reached at [email protected]. B. Steffi Diana can be reached at
[email protected]. R. Rajaram can be reached at
[email protected]@tce.edu.
Ad-hoc networks do not use specialized routers for path
discovery and traffic routing develops the wireless backbone
architecture. This means that certain nodes must be selected
to form the backbone. One of the general approaches to build
up a cluster based network architecture is to design an
algorithm to self-organize themselves into cluster based
network architecture. This is achieved by partitioning ad hoc
networks into clusters. Certain nodes, known as cluster-
heads, would be responsible for the formation of cluster and
maintenance of the topology of the network, and also for the
resource allocation to all the nodes belonging to their clusters.
The clustering algorithm is usually performed in two phases:
clustering formation and clustering maintenance [3]. In the
clustering formation phase, the election of a cluster-head
among the nodes in the network is conducted. The functions of
cluster heads are the coordination of the clustering process and
relaying routers in data packet delivery. After electing cluster-
heads, some of nodes move out from the current cluster and
are attached to another cluster. Other cluster-heads are
downed. This leads to the second phase, namely, clustering
maintenance. In light of this, this paper aims to avoid
excessive computation in the cluster maintenance, and current
cluster structure should be preserved as much as possible.
In this paper, we propose an enhancement on a weighted
clustering algorithm [1, 5] (WCA) by maintaining stable
clusters. In WCA, a node is selected to be the cluster-head
when it has the minimum weighted sum of four indices: the
number of potential members, the sum of the distances to
other nodes is its radio distance, the node‟s average moving
speed and the battery life of the node. However, only the
individual nodes‟ mobility is measured in WCA, whereas the
relative mobility of a node and its neighbors is more important
to the cluster stability. The ignorance of the relative mobility
will lead to the situation that the high mobility of nodes causes
a high frequency of re-affiliations, which will increase the
network overhead. To solve this problem, we propose an
enhanced weight-based clustering algorithm using mobility
prediction scheme (MWCAMP). This can enhance the
stability of the network by taking the relative mobility of a
node and its neighbors into consideration for the clustering
formation [1, 2, 5] and maintenance, by predicting the
mobility of a node using the link expiration time [12].
The remainder of this paper is organized as follows. In
Section 2, we review the several relevant clustering algorithms
proposed previously and their limitations. Section 3 presents
A Modified Weighted Clustering Algorithm for
Stable Clustering using Mobility Prediction Scheme
S. Muthuramalingam, R. Viveka, B. Steffi Diana and R. Rajaram Department of Information Technology, Thiagarajar College of Engineering,
Madurai, India
I
10 INTERNETWORKING INDONESIA JOURNAL MUTHURAMALINGAM ET AL.
the proposed algorithm for ad hoc networks. Section 4
discusses the proposed algorithm. Section 5 discusses the
simulation results and analysis. Finally, Section 6 concludes
this paper.
II. RELATED WORKS AND CURRENT MOTIVATION
Recently a number of clustering algorithms have been
proposed to choose cluster-heads based on the speed and
direction, mobility, energy, position, and the number of
neighbors of a given node. These efforts present advantages
but also have some drawbacks, such as the high computational
overhead for both clustering algorithm execution and update
operations.
The Highest Degree Algorithm is also known as
connectivity-based algorithm [3]. This algorithm is based on
the degree of nodes assumed to be the number of neighbors of
a given node. Whenever the election procedure is needed,
nodes broadcast their Identifier (ID) which is assumed to be
unique in the same network. According to the number of
received IDs every node computes its degree and the one
having the maximum degree (no of adjacent nodes) becomes
cluster-head (CH). Major drawbacks of this algorithm include
the situation where the degree of a node changes very
frequently, and thus the CHs are not likely to play their role as
cluster-heads for very long. In addition, as the number of
ordinary nodes in a cluster is increased, the throughput drops
and system performance degrades. All these drawbacks occur
because this approach does not have any restrictions on the
upper bound on the number of nodes in a cluster.
The Lowest-Identifier (LID) is also known as identifier-
based clustering algorithm [4]. This approach chooses the
node with the lowest ID as a cluster-head. The system
performance is better than Highest-Degree in terms of
throughput. Major drawbacks of this algorithm are its bias
towards nodes with smaller IDs which may lead to the battery
drainage of certain nodes, and it does not attempt to balance
the load uniformly across all the nodes.
The Distributed Clustering Algorithm (DCA) [6, 7] and
Distributed Mobility Adaptive Clustering Algorithm (DMAC).
In this approach, each node is assigned weights (a real number
above zero) based on its suitability of being a cluster-head. A
node is chosen to be a cluster-head if its weight is higher than
any of its neighbor‟s weight; otherwise, it joins a neighboring
cluster-head. The smaller weighted node ID is chosen in case
of a tie. The DCA makes an assumption that the network
topology does not change during the execution of the
algorithm. To verify the performance of the system, the nodes
were assigned weights which varied linearly with their speeds
but with negative slope. Results proved that the number of
updates required is smaller than the Highest-Degree and
Lowest-ID heuristics. Since node weights were varied in each
simulation cycle, computing the cluster-heads becomes very
expensive and there are no optimizations on the system
parameters such as throughput and power control.
The Weighted Clustering Algorithm (WCA) [5] obtains
1-hop clusters with one cluster-head. The election of the
cluster-head is based on the weight of each node. It takes four
factors into consideration and makes the selection of cluster-
head and maintenance of cluster more reasonable. The four
factors are node degree (number of neighbors), distance
summation to all its neighboring nodes, mobility and
remaining battery power. Although WCA has proved better
performance than all the previous algorithms, it has a
drawback in needing to know the weights of all the nodes
before starting the clustering process and in draining the CHs
rapidly. As a result, the overhead induced by WCA is very
high.
III. PROPOSED WORK
In this section, we present the proposed Enhanced
Weighted Clustering Algorithm using mobility prediction
scheme (MWCAMP). MWCAMP consists of the clustering
formation and clustering maintenance phases. Before
describing our clustering algorithm in detail, we make the
following assumptions:
I. The network topology is static during the execution of
the clustering algorithm.
II. Each mobile node joins exactly one cluster-head.
A. Phase-I: Clustering Formation
In WCA, the goal is to minimize the value of the sum of all
the cluster heads‟ weighted costs. Here a node is selected as
cluster head when it minimize a function of four criteria such
as degree (the number of direct link to its neighbors), sum of
distance between cluster head and other nodes, mobility of
nodes and battery power of the nodes. WCA has high re-
affiliation frequency [7, 8] which will increase the
communication overhead. Thus, we present an enhanced
algorithm to reduce the amount of re-affiliation frequency
corresponding to the number of nodes that is not „„proper‟‟ in
current cluster. It corresponds to nodes that detach from
current cluster and move to another cluster. In order to reduce
the re-affiliation frequency, we should decrease the number of
improper nodes. When the idea reflects on the cluster head
election, the key is to choose „„stable‟‟ nodes as cluster heads
as possible. The stability of a node is relative to its neighbors.
In WCA, the running average speed for every node till
current time T, it is computed [9, 10] as
1
2 2 21 1
1
1(( ) ( ) )
T
i t t t t
t
M X X Y YT
where (Xt, Yt) and (Xt-1, Yt-1) are the coordinates of the node i
at time t and (t -1), respectively. It is shown that is the
absolute mobility of node and cannot indicate information of
stability between node and its neighbors. Therefore we present
an improved parameter ̅ (relative mobility parameter) to
substitute (absolute mobility parameter). Here ̅ is
inversely proportional to stability factor which is measured
in sense of relative mobility.
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 11
ISSN: 1942-9703 / © 2009 IIJ
The stability [13] of node “i” is computed from two aspects:
I. i : The relative average speed of i and its neighbors.
The larger i is, the more unstable the node is,
comparing to its neighbors.
II. iNC : The change of node‟s neighbors. The value of
iNC can indicate the change of topology surrounding
node i.
We also use a combined function of i and iNC to
computeiS . Another improvement of our algorithm is that we
compute the average relative distances instead of the sum of
distances.
The proposed MWCAMP described as follows
1 2 3 4ii i i iw w w D w M w P
where
I. i is the degree of each node i (i.e., nodes within its
transmission range)
II. iD is the average relative distances each node i with
all its neighbors.
III. iM is the relative mobility of node i
IV. iP is the battery power of node i.
where w1, w2 , w3 and w4 are the weighting factors for the
corresponding system parameters.
Figure 1
Figure 2
B. Phase-II: Clustering Maintenance Using Mobility
prediction
The mobility of nodes coupled with the transient nature of
wireless media often results in a highly dynamic network
topology. Due to mobility some nodes will detach from the
current cluster and attach itself to some other cluster. The
process of joining a new cluster is known as re-affiliation. If
the re-affiliation fails, the whole network will recall the cluster
head election routine. One disadvantage of WCA is high re-
affiliation frequency. High frequency of re-affiliation will
increase the communication overhead. Thus, reducing the
amount of re-affiliation is necessary in ad hoc networks. To
prevent this we go for mobility prediction schemes. The
impact of mobility prediction schemes on the temporal
stability of the clusters obtained using a mobility-aware
clustering framework. We propose a simple framework for a
mobility prediction-based clustering to enhance the cluster
stability.
One way to predict the mobility of nodes is using the
Link Expiration Time [13]. The impact of mobility prediction
schemes on the stability of the clusters obtained using a
mobility-aware clustering framework. Compute the Link
Expiration Time (LET) to predict the duration of a wireless
link between two nodes in the network. The approach assumes
that the direction and speed of motion of the mobile nodes
does not change during the prediction interval.
C. Link Expiration Time (LET)
The Link Expiration Time (LET) is a simple prediction
scheme that determines the duration of a wireless link between
two mobile nodes. Dynamic clustering in ad hoc networks has
also been extensively studied in the literature. Several
distributed clustering algorithms for MANETs have been
proposed. While some schemes try to balance the energy
consumption for mobile nodes, others aim to minimize the
clustering-related maintenance costs. Combined metrics based
clustering schemes take a number of metrics into account for
cluster configuration. The Weighted Clustering Algorithm
(WCA) [5] is one such scheme, where four parameters are
considered for the cluster head election procedure, which are
representative of the degree, the sum of the distances to other
nodes in its radio distance, mobility, and battery power of the
mobile nodes. Here we propose an enhanced WCA which can
enhance the stability of the network. Such a scheme can be
tuned flexibly the parameters to suit to different scenarios. To
calculate the duration of link between two mobile nodes, we
assume that their location, speed and direction of movement
remain constant.
Here let:
Location of node i and node j at time t be given by
(xi , yi) and (xj ,yj).
Vi and V j be the speeds,
θi and θj be the directions of the nodes i and j
respectively.
12 INTERNETWORKING INDONESIA JOURNAL MUTHURAMALINGAM ET AL.
If the transmission range of the nodes is r, then the
link expiration time Dt is given by the formula given
below
2 2 2 2
2 2
( ) ( ) ( )
( )t
ab cd a c r ad bcD
a c
where
cos cosi i j ja v v
i jb x x
sin sini i j jc v v
i jd y y
The LET gives an upper bound on the estimate of the
residence time of a node in a cluster. In the proposed
clustering framework, when LET-based prediction is used, a
node is allowed to join a cluster only if the predicted LET of
the link between the node and the cluster head is greater than
the cluster‟s admission criteria Tj [13, 14]. For every node N
that detach from current cluster we check whether the node is
a Cluster Head (or ) Cluster member.
I. If it is a Cluster Head then call for cluster head election
within the particular cluster and form a new cluster.
II. If it is a Cluster member then calculate Link Expiration
Time with Cluster Head of each cluster and the node that re-
affiliate must be within transmission range of cluster head
where transmission range is fixed.
Check whether LET is greater than threshold value (Tj),
Here Tj is average of all LET, and if it is greater then the Node
is eligible to join the particular cluster which shares greater
LET.
Figure 3
Figure 4
IV. ENHANCED WEIGHTED CLUSTERING
ALGORITHM USING MOBILITY PREDICTION
Consider Node Ni in transmission range r, positions of
node Ni be ( Xi Yi ), Nj be nodes that detach from current
cluster, where 1 ≤ i ≤ n , 1 ≤ j ≤ n and 1 ≤ k ≤ n.
1: calculate degree of node Ni
i ( )ijC
where Cij =1, if nodes Ni and Nj are connected else Cij =0 .
(Where Cij be connection between node Ni and Nj, Where 1
≤ i ≤ n , 1 ≤ j ≤ n).
2: calculate relative sum of distance iD from nodes iN to its
members,
{ ( , )}
j i
i j
i
N N i
dist N ND
where 1 ≤ i ≤ n, Nj is the node the establish link with the node
Ni.
3: iM is the running average speed for every node iN till
current time T is calculated using formula
1
2 2 21 1
1
1(( ) ( ) )
T
i t t t t
t
M X X Y YT
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 13
ISSN: 1942-9703 / © 2009 IIJ
4: For every node iN , compute the average speed iA using
formula
1
j i
i i
N Ni
A M
Where 1 ≤ i ≤ n, Nj is the node that establish link with the
node Ni
5: compute the speed-difference i as
i i iM A
where 1 ≤ i ≤ n.
6: For every node Ni compute the neighbor change NCi at time
t.
}{}{
}{}{
21
21
tt
tt
ii
ii
i
NN
NNNC
7: Compute the stability factor S i as
1
11 ii is a NC
where a is an adjustable integer which is decided by the
stability of the node.
8: Thus we can get the improved parameter iM as
i
i
bM
S
where b is an integer decided by the speed of node. Both a and
b are constant to make Si more reasonable, avoiding to be too
large or less.
9: Calculate weight value
1 2 3 4ii i i iw w w D w M w P
where Pi is the battery power of node, and w1= 0.7, w2= 0.05,
w3= 0.05, and w4= 0.2.
10: The node with minimum weight value is elected as
Cluster Head. That is
)}(min{ iii NwCH .
11: Now cluster members are added to the cluster head. The
nodes that establish link with that cluster head are called
cluster members and they are grouped together to form a
cluster. Thus cluster is formed by
[ { | }]
{ }
where
{ }
are previously formed cluster, where 1=k=n. Repeat step 1 to
8 until every node is a member of cluster.
12: For every node N that detach from current cluster we
check whether the node is a Cluster Head (or Cluster
member).
I. If it is a Cluster Head then call for cluster head
election within the particular cluster and form a new
cluster.
II. If it is a Cluster member then calculate LET (Link
Expiration Time) with Cluster Head CHi of each
cluster Ci and Nj must be within transmission range of CHi .where transmission range is fixed.
LET i be the duration of the link between the two nodes is
given by the formula given above in phase II and III.
13: Admission Criteria:
Check whether LET is greater than threshold value (Tj).
If it is greater then the Node Nj is eligible to join the particular
cluster Cj which shares greater LET (where Tj is average of all
LET calculated). Repeat steps 10 and 11 for every node detach
from current cluster. Else END.
V. EXPERIMENTAL SETUP AND RESULTS
In this section, we present the performance of the
proposed WCA simulated by NS2.We simulate a system of N
nodes on an 1500 m × 1500 m area. The value of N is varied
between 10 and 70 and transmission range is 500m. The nodes
move randomly in all directions with a maximum speed varied
between 20m/s and 50 m/s. The power for each node is varied
between 40 to 100 units. Because the mobility of node is an
important parameter in our case, the corresponding weight is
chosen to be high. The values of the weights used in our
simulation are: w1 = 0.7, w2 = 0.05, w3 = 0.05 and w4 =
0.2. Note that the values may be adjusted according to the
system requirements.
The performance of algorithms is measured in terms of the
number of re-affiliation count and no of clusters formed.
14 INTERNETWORKING INDONESIA JOURNAL MUTHURAMALINGAM ET AL.
Figure 5: Average re-affiliation frequency vs node number
Figure 6: Comparison between WCA and our proposed work on basis of no of clusters formed.
Figure 5 depicts the average re-affiliation count versus the
total number of nodes in the network where maximum speed
is 50m/s and the transmission range is 500m. Here the nodes
are organized into clusters and cluster head is elected. In
previously designed clustering framework using weighted
clustering algorithm, re-affiliation time for a given number of
nodes are determined and plotted. In our enhanced weighted
clustering algorithm, nodes form into clusters and elect cluster
head and the node which detach from current cluster are
joined by predicting their mobility using link expiration time.
Here future prediction (mobility) is done on basis of direction
and speed of nodes and so re-affiliation frequency is reduced.
As the number of nodes increased, the increasing rate of re-
affiliation slowed down. According to the result, MWCAMP
gives less re-affiliation than WCA especially for the high node
density. Thus we form a stable cluster with MWCAMP.
Here the number of clusters formed for a given number of
nodes is plotted. The number clusters formed should be
reduced. Here no of clusters formed are comparatively
reduced.
Comparison between WCA and our proposed work on
basis of throughput and simulation time is given in figure 7
and 8. Figure 7 represents the throughput of forwarding
message in WCA. Figure 8 represents the throughput of
forwarding message in our proposed work MWCAMP.
Figure 7: This graph represent WCA output. The Transmission
time is from 1sec to 2 sec. Here throughput of forwarding message is decreasing and it is not stable.
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 15
ISSN: 1942-9703 / © 2009 IIJ
Figure 8: This graph represent MWCAMP output. The
Transmission time is from 1sec to 2 sec. Here throughput of forwarding message is increasing and stable.
VI. CONCLUSION
In this paper we have presented an enhanced weight
based clustering algorithm using mobility prediction
(MWCAMP) that can be applied in MANETs to improve upon
their stability and to reduce re-affiliation of the nodes.
MWCAMP mainly focuses on reducing the instability caused
by high-speed moving nodes, by taking relative mobility of
node and its neighbors into consideration. Since WCA support
stable cluster head election and the disadvantage is re-
affiliation of nodes which is reduced by mobility prediction, it
results in stable clustering. The performance of the proposed
MWCAMP demonstrated that it outperforms WCA in terms of
re-affiliation count.
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[11] Yingpei Zeng, Jiannong Cao, Shanqing Guo, Kai Yang, Li Xie. “A
Secure Weighted Clustering Algorithm in Wireless Ad Hoc Networks”.
IEEE conference on Wireless Communications and Networking
Conference. (5-8 April, 2009).
[12] (Bricard-Vieu.V, Nasser. N, and Mikou, NA. “Mobility Prediction-based
Weighted Clustering Algorithm Using Local Cluster-heads Election for
QoS in MANETs”. IEEE International Conference on Wireless and
Mobile Computing, Networking and Communications. (2006).
[13] Andronache, A, Rothkugel, S. “NLWCA Node and Link Weighted
Clustering Algorithm for Backbone-Assisted Mobile Ad Hoc
Networks”. Seventh International Conference on Networking. (13-18
April 2008).
[14] Bouk S.H, Sasase I. “Energy Efficient and Stable Weight Based
Clustering for mobile ad hoc networks”. 2nd International Conference
on Signal Processing and Communication Systems. (15-17 Dec. 2008).
S. Muthuramalingam has over 6 years of teaching
experience and is currently working as a Asst Prof
in Thiagarajar college of Engineering. He finished
his bachelor of Engineering (computer science) at
Shanmugha college of engineering, Thanjavur in
the year 1997. And he completed his M.E in
Kalasalingam University in 2002. He published two
papers in International journal on applications of
graph theory in wireless ad hoc networks and
sensor networks, and IJCEE. He has published
papers in the national and IEEE international
conferences such as IEEE AMS 2008 IEEE
Netcomm2010, NCCN‟09,VIT, NCACT,SAATRA
and NCIM 2007. He is pursuing PhD degree in the
field of Mobile communication at Anna University
Chennai, India.
16 INTERNETWORKING INDONESIA JOURNAL MUTHURAMALINGAM ET AL.
R. Rajaram completed his PhD in TCE, Madurai
Kamaraj University in the year 1979, and the
MTech degree in IIT Karagpur in the year 1971. He
has published about 100 papers in a number of
journals such as the International journal of
Computational Engineering Science, Journal of
Optics and Journal of the Institute of Engineers. He
is a life member of Institution of engineers,
Computational Society of India, India Society for
Tech Education. Currently working as the Dean
CSE/IT & Head of the Department of IT in
Thiagarajar college of engineering..
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 17
ISSN: 1942-9703 / © 2010 IIJ
Abstract—The Indonesian government is planning to
implement the Single Identity Number (SIN) as the primary
identification method for residents of Indonesia. With this SIN
implementation, it is hoped that a number of residential
administrative issues, such as an individual having multiple
identity cards (KTP), can be resolved. Furthermore, residents
will have the advantage of only needing one identity form and not
having to remember multiple identity information. It is hoped
that just by using a single SIN a resident can obtain various
government services more efficiently. However, on the other
hand the use of the SIN introduces the potential for security
attacks through the misuse of a SIN by people other than its
owner or assignee. As such additional security mechanisms are
needed to ensure that a SIN is used only by its proper owner or
assignee. This paper aims at describing a proposal for a
mechanism to secure the SIN, based on the combined use
fingerprints and the QR Code.
Pemerintah Indonesia telah merencanakan bahwa pada tahun
2012 akan diimplementasikan Single Identity Number (SIN)
sebagai identitas tunggal penduduk Indonesia. Dengan adanya
SIN ini maka diharapkan permasalahan-permasalahan
administrasi kependudukan seperti misalnya satu orang
memiliki lebih dari satu buah KTP dapat diatasi. Selain itu bagi
penduduk juga akan diperoleh kemudahan lainnya yaitu tidak
perlunya seseorang untuk memiliki banyak identitas dan
mengingat banyak ID. Cukup dengan menggunakan SIN,
penduduk dapat menggunakan berbagai macam layanan
pemerintahan yang berbeda-beda. Dibalik semua kemudahan
ini, terdapat suatu potensi ancaman keamanan jika SIN
disalahgunakan oleh orang lain. Untuk itu diperlukan suatu
mekanisme pengamanan agar SIN memang diberikan dan
dimiliki oleh orang yang tepat. Paper ini bertujuan untuk
menjelaskan suatu usulan mekanisme pengamanan SIN dengan
menggunakan sidik jari dan QR Code.
Index Terms—Computer Security, Identity, Authentication.
Fridh Zurriyadi Ridwan is with the R&D Centre of PT Telekomunikasi
Indonesia (PT TELKOM) in Jakarta, Indonesia. He can be reached at:
Hariyo Santoso is with the Consumer Directorate of PT Telekomunikasi
Indonesia (PT TELKOM) in Jakarta, Indonesia. He can be reached at:
Dr. Wiseto Agung is with the R&D Centre of PT Telekomunikasi
Indonesia (PT TELKOM) in Jakarta, Indonesia. He can be reached at:
I. PENDAHULUAN
emerintah Indonesia telah mencanakan bahwa pada tahun
2012 akan diimplementasikan sistim Single Identity
Number (SIN) sebagai identitas tunggal penduduk Indonesia.
SIN ini adalah 16 digit angka yang digunakan sebagai
identitas unik dari seluruh penduduk Indonesia. Seperti
banyak diketahui, saat ini masyarakat mengantongi banyak
nomor identitas, mulai dari nomor Kartu Tanda Penduduk
(KTP), nomor Surat Ijin Mengemudi (SIM) dan lainnya.
Penerapan nomor identitas tunggal ini juga dimaksudkan
untuk memudahkan seseorang dalam setiap pengurusan
dokumen dan berbagai keperluan lainnya.[1] Dengan
diterapkannya SIN, diharapkan akan sangat banyak manfaat
yang diperoleh seperti diantaranya: tidak perlunya seseorang
untuk memiliki banyak identitas dan mengingat banyak ID.
Cukup dengan menggunakan SIN, penduduk sudah bisa
mendapatkan berbagai macam layanan pemerintahan yang
berbeda-beda. Selain itu permasalahan KTP ganda, informasi
pajak yang terintegrasi dan lain-lain juga dapat disolusikan
dengan menggunakan SIN. Akan tetapi dibalik semua
kemudahan ini, terdapat suatu potensi ancaman keamanan jika
SIN disalahgunakan oleh orang lain. Untuk itu diperlukan
suatu mekanisme pengamanan agar SIN memang diberikan
kepada dan dimiliki oleh orang yang tepat. Pada bagian
selanjutnya akan dibahas mengenai QR code dan sidik jari
yang diusulkan untuk digunakan sebagai pengaman dari SIN.
II. QR CODE
Quick Response (QR) code adalah sebuah kode matriks
dalam bentuk dua dimensi yang dikembangkan oleh
perusahaan Jepang Denso-Wave pada tahun 1994. Gambar 1
menunjukkan contoh bentuk QR Code.
Beberapa kelebihan dalam menggunakan QR Code adalah
sebagai berikut:
Dibandingkan dengan barcode dua dimensi lain yang ada
(misalnya: Datamatrix, PDF417 dan lain-lain) QR Code
mampu menyimpan informasi cukup banyak (maksimum
4296 karakter untuk alfanumerik atau 7089 digit numerik)
[3]. Sebagai ilustrasi, barcode satu dimensi standar yang
banyak digunakan hanya mampu menampung informasi
sebanyak 20 digit [4].
Memiliki kemampuan error correction. Data dapat
diperbaiki meskipun QR code mengalami kerusakan atau
Mengamankan Single Identity Number (SIN)
Menggunakan QR Code dan Sidik Jari
Fridh Zurriyadi Ridwan, Hariyo Santoso, dan Wiseto P. Agung
PT Telekomunikasi Indonesia
P
18 INTERNETWORKING INDONESIA JOURNAL RIDWAN ET AL.
ISSN: 1942-9703 / © 2010 IIJ
kotor sebagian.
Dapat dicetak di KTP dengan ukuran optimum sekitar
1,5cm x 1,5cm, dimana terdapat 57 x 57 modul yang
dapat menyimpan data hingga 400 karakter
(alphanumerik).
Proses pembacaan yang cepat karena tidak harus dibaca
dalam posisi sudut tertentu seperti halnya barcode satu
dimensi [4].
Standard (ISO/IEC18004) dan memiliki banyak reader
untuk terminal ponsel dan PC [5].
Mudah dibawa-bawa.
Lebih murah jika dibandingkan media penyimpanan
smartcard berbasis chip.
Gambar 1. QR Code
QR code saat ini banyak digunakan di Jepang. Di Indonesia
penggunaan QR code belum terlalu populer. Akan tetapi
aplikasi QR reader untuk berbagai macam tipe ponsel dan PC
cukup banyak tersedia untuk diunduh secara gratis melalui
Internet. Di Indonesia QR Code digunakan di beberapa artikel
dari harian Kompas untuk menyimpan URL dari artikel terkait
yang dapat diakses melalui aplikasi browser di ponsel.
III. SIDIK JARI
Sidik jari setiap manusia sifatnya adalah unik, sehingga
sidik jari merupakan alat yang dapat dipercaya untuk
memastikan bahwa SIN yang digunakan adalah dimiliki oleh
orang yang benar. Dengan menggunakan sidik jari, pengguna
juga tidak perlu mengingat SIN-nya atau kata kunci jika
dibutuhkan. Cukup dengan menyediakan informasi sidik
jarinya melalui mesin pembaca sidik jari, maka proses
otentikasi atas SIN dapat dilakukan dengan mudah. Sidik jari
juga dapat dikonversi ke dalam bentuk digital, sehingga dapat
disimpan dalam bentuk basis data RDBMS biasa. Dalam
menyimpan data sidik jari, biasanya sistem mentranslasikan
data sidik jari ke dalam bentuk numerik, sehingga dapat
disimpan dalam basis data. Beberapa sistem mentranslasikan
sidik jari ke dalam numerik dalam jumlah yang cukup banyak.
Untuk meringkasnya, dapat diterapkan mekanisme
pengkompresian dengan algoritma tertentu.
Sidik jari cukup sensitif terhadap akurasi pembacaan mesin
pembaca sidik jari, sehingga mungkin dibutuhkan beberapa
kali proses pembacaan (scanning) untuk melakukan proses
otentikasi. Saat ini sudah banyak mesin pembaca sidik jari
yang menggunakan terminal USB dan bentuknya cukup kecil,
sehingga memudahkan dalam proses instalasi dan mobilitas
jika dibutuhkan dengan menggunakan notebook sebagai
terminal pengganti PC.
IV. METODA IDENTIFIKASI PENDUDUK
Salah satu bentuk usulan pengamanan atas SIN adalah
dengan melakukan pemetaan informasi-informasi unik dari
seseorang dengan SIN yang diberikan. Informasi unik dari
seseorang biasanya menggunakan data biometrik yang umum
digunakan seperti sidik jari atau retina. Sidik jari saat ini lebih
banyak digunakan karena banyak reader yang tersedia di
pasaran dengan harga yang relatif murah. Informasi-informasi
unik yang akan digunakan dalam solusi ini diantaranya adalah:
Data sidik jari (fingerprint).
Nama.
Tempat & tanggal lahir.
Golongan Darah.
URL alamat dari data sidik jari orang tersebut.
Semua data-data tersebut harus dapat direlasikan 1:1 dengan
pemilik SIN dan dapat diakses dengan mudah untuk
melakukan verifikasi.
Untuk mendukung kebutuhan ini, maka sebagian data-data
tersebut disimpan dalam bentuk barcode 2 dimensi yaitu
menggunakan QR Code. Sedangkan khusus data sidik jari
akan disimpan dalam bentuk basis data.
Untuk lebih mengamankan informasi yang disimpan di
dalam QR Code, maka sebagian informasi (misalnya URL
alamat data sidik jari) dapat dienkripsi dengan menggunakan
algoritma yang dibuat khusus yang hanya dapat dibaca oleh
aplikasi yang dikembangkan khusus pula.
V. KONFIGURASI SISTEM
Di dalam konfigurasi sistem yang diusulkan, QR Code
digunakan untuk menyimpan SIN dan informasi-informasi
unik lainnya seperti tanggal lahir, golongan darah dan URL,
dengan parameter yang unik untuk setiap penduduk, untuk
mengakses basis data SIN.
Ada dua cara penambahan QR code yang diusulkan bagi
KTP yang saat ini digunakan penduduk. Cara pertama adalah
pembuatan QR Code dilakukan di setiap kantor Kelurahan dan
dicetak dengan ukuran yang cukup kecil agar dapat
ditempelkan/ditambahkan di kartu SIN/KTP. Cara kedua
adalah pada saat pembuatan kartu identitas baru, sudah
menyertakan QR Code yang telah dibuat. Selanjutnya QR
Code ini dapat dibaca dengan menggunakan ponsel yang
memiliki kamera atau PC dengan menggunakan web camera
yang sebelumnya telah diinstal aplikasi QR Reader.
Di dalam konfigurasi sistem yang diusulkan, data sidik jari
disimpan di dalam suatu basis data khusus yang dapat diakses
melalui jaringan privat virtual (VPN). Jaringan privat virtual
digunakan untuk menghubungkan kantor Kelurahan dengan
pusat data SIN. Dengan menggunakan jaringan privat virtual,
maka dapat dijaga keamanan komunikasi antara Kelurahan
dan pusat data SIN yang mungkin terpisah secara fisik dari
ancaman penyadapan informasi oleh pengguna yang tidak
terdaftar di dalam sistem SIN. Sidik jari ini diambil dari setiap
penduduk di Kantor kelurahan terdekat dan kemudian
direlasikan dengan SIN penduduk tersebut. Idealnya data sidik
jari ini dapat diakses secara nasional sehingga dapat
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ISSN: 1942-9703 / © 2010 IIJ
membantu proses verifikasi apakah seseorang sudah atau
belum pernah memiliki SIN atau identitas lainnya yang
dikeluarkan dari dearah lain.
Gambar 2 berikut menunjukkan konfigurasi dari sistem
yang diusulkan.
Gambar 2. Konfigurasi Sistem
Konten dari basis data SIN juga harus dijamin
keamanannya. Untuk itu informasi sidik jari yang disimpan di
dalam basis data harus disimpan di dalam format yang
terenkripsi (encrypted data). Sedangkan hubungan antara
kantor kelurahan dengan pusat data SIN direkomendasikan
menggunakan jaringan privat virtual. Untuk menjamin bahwa
hanya petugas dari kantor kelurahan yang berwenang saja
yang dapat mengakses pusat data SIN, maka proses otentikasi
dapat menyertakan juga MAC address dari terminal PC yang
digunakan oleh petugas Kelurahan.
VI. ALIRAN PROSES
Untuk mengimplementasikan sistem ini, aliran proses yang
diusulkan adalah sebagai berikut:
A. Pembuatan Kartu Identitas
1. Penduduk harus datang ke kantor Kelurahan dimana ia
tinggal untuk melakukan pengambilan data sidik jari.
Di kantor Kelurahan disediakan perangkat pembaca
sidik jari. Untuk orang-orang yang tidak mampu
datang ke kantor Kelurahan karena sakit atau cacat
maka petugas Kelurahan yang akan mendatangi orang-
orang tersebut dengan membawa komputer notebook
dan perangkat pembaca sidik jari.
2. Petugas akan memeriksa ke basis data SIN apakah
orang tersebut sudah memiliki SIN dengan
mencocokkan sidik jari yang diperolehnya dengan
basis data sidik jari yang sudah ada.
3. Jika ditemukan sidik jari yang cocok dan orang
tersebut sudah memiliki SIN, maka petugas Kelurahan
tidak dapat membuat kartu identitas baru dengan SIN
baru untuk orang tersebut.
4. Jika tidak ditemukan sidik jari yang cocok, maka data
sidik jari yang diperoleh kemudian disimpan di dalam
basis data SIN dan direlasikan dengan SIN orang
tersebut.
5. Petugas kependudukan kemudian membuat QR code
yang berisi informasi-informasi unik dari orang
tersebut.
6. Selanjutnya petugas kependudukan membuat kartu
identitas yang menyertakan QR code tersebut.
B. Pengecekan Kartu Identitas
1. Penduduk diharuskan untuk menunjukkan kartu
identitas untuk mengajukan suatu layanan masyarakat
(misalnya untuk mengajukan permohonan IMB).
2. Dengan menggunakan aplikasi QR Reader yang
diinstal di PC atau di ponsel, Petugas Kelurahan atau
petugas dari Instansi terkait akan membaca QR code
yang ada pada kartu identitas untuk mendapatkan
informasi unik yang dibutuhkan.
3. Jika dibutuhkan untuk otentikasi lebih lanjut, maka
petugas dapat meminta orang tersebut untuk
mencocokkan sidik jarinya dengan basis data sidik jari.
Aplikasi QR Reader akan membaca data URL pada
QR code milik orang tersebut yang berisi alamat untuk
mengakses informasi sidik jari dari orang tersebut.
VII. BISNIS PROSES PENUNJANG
Untuk mengoptimalkan pemanfaatan QR code dan sidik jari
dalam sistem SIN, diperlukan beberapa hal lain sehingga
secara kesisteman SIN dapat digunakan untuk banyak
keperluan dengan mudah dan tidak membutuhkan proses
bisnis yang rumit.
QR code yang berisi SIN dan sidik jari harus dicetak
dalam Kartu Tanda Penduduk (KTP).
Tersedia QR code dalam bentuk softcopy, sehingga
transaksi dapat dilakukan secara online atau dengan
menggunakan perangkat portabel seperti ponsel. Dengan
semakin mudahnya penyimpanan dan proses yang tidak
rumit, masyarakat akan lebih terbiasa dengan
pemanfaatan SIN.
Dapat diintegrasikan dengan sistem pelayanan satu atap.
VIII. PENUTUP
Penggunaan QR Code dan data sidik jari diharapkan dapat
membantu pengamanan SIN yang akan diimplementasikan
agar tidak disalahgunakan oleh orang yang tidak berhak untuk
mengakses data-data atau layanan-layanan pribadi dari
pemilik SIN. Penggunaan QR code merupakan salah satu
solusi yang relatif murah jika dibandingkan dengan
menggunakan smartcard berbasis chip. Untuk implementasi
dalam skala nasional, perlu dipertimbangkan agar konfigurasi
pusat data SIN didesain dengan arsitektur terdistribusi,
20 INTERNETWORKING INDONESIA JOURNAL RIDWAN ET AL.
ISSN: 1942-9703 / © 2010 IIJ
sehingga waktu yang dibutuhkan untuk melakukan proses
pencocokan sidik jari dari tempat-tempat yang lokasinya
cukup jauh dengan pusat data SIN tetap seminimal mungkin.
QR Code juga dapat digunakan untuk menyimpan
informasi-informasi lainnya seperti untuk menyimpan
beberapa ID lain yang mungkin saja masih digunakan
bersama-sama dengan SIN selama masa transisi (misalnya
nomor KTP lama, NPWP atau SIM).
Pengembangan lebih lanjut yang dapat dilakukan adalah
pembacaan QR Code dan proses otentikasi sidik jari dapat
dilakukan melalui area publik dengan memanfaatkan jaringan
Internet yang tersedia atau melalui jaringan komunikasi
nirkabel yang tersedia (GSM, CDMA). Untuk hal ini perlu
dikaji lebih mendalam mengenai aspek pengamanan transaksi
data yang dilakukan.
Pengembangan lebih lanjut lainnya adalah jika metode ini
digunakan pada smartcard berbasis chip. Chip dapat
digunakan untuk menyimpan data-data sidik jari secara
offline, sehingga dapat mempercepat proses otentikasi sidik
jari jika dibandingkan dengan harus melakukan pengecekan
melalui jaringan privat karena tidak perlu melakukan koneksi
dan proses otentikasi ke jaringan privat terlebih dahulu.
DAFTAR PUSAKA
[1] “Kementrian PAN Mewujudkan Single Identity Number”, [Online].
Available: http://bataviase.co.id/detailberita-10574703.html, 29 Januari
2010, diakses: 6 Apr il 2010.
[2] “2010, Jakarta Terapkan „Single Identity Number‟" , [Online].
Available:
http://megapolitan.kompas.com/read/2009/09/25/12381886/2010..Jakart
a.Terapkan.Single.Identity.Number., 25 September 2009, diakses: 6
April 2010
[3] “QR Code”, [Online]. Available: http://en.wikipedia.org/wiki/QR_Code.
[4] About QR-Codes, [Online]. Available: http://www.mobile-
barcodes.com/about-qr-codes/#barcodes-vs-qr-codes
[5] “QR Code Standardization”, [Online]. Available: http://www.denso-
wave.com/qrcode/qrstandard-e.html, diakses: 6 April 2010
[6] “QR Code Features”, [Online]. Available: http://www.denso-
wave.com/qrcode/qrfeature-e.html, diakses: 7 April 2010
[7] “Fingerprint”, [Online]. Available:
http://en.wikipedia.org/wiki/Fingerprint
Fridh Zurriyadi Ridwan received the Informatical
Engineering degree from the TELKOM School of
Technology in Bandung, Indonesia in 1997 and a
Master of Information Technology degree from the
Computer Science Faculty of the University of
Indonesia (UI) in 2008. From 1997 to 2008 he
worked as an engineer in the R&D Center of PT
Telekomunikasi Indonesia (TELKOM). He is
currently working as a researcher in the TELKOM
R&D Center. His research interest are mostly
related with telecommunication services and
products. He is also actively involved in several
Asia Pacific Telecommunity (APT) joint research
work with researchers from Japan.
Hariyo Santoso received his Electrical
Engineering degree from the TELKOM School of
Technology in Bandung, Indonesia in 1997 and a
Master of Information Technology degree from the
Computer Science Faculty of the University of
Indonesia (UI) in 2009. From 1997 to 2009 he
worked as an engineer and researcher within the
R&D Center of PT Telekomunikasi Indonesia
(TELKOM). He is currently working in the
TELKOM Consumer Directorate as a Senior
Officer of the Device & CPE Product Development
and Deployment. He also involved in several Asia
Pacific Telecommunity (APT) joint research work
with researchers from Japan.
Dr Wiseto Agung received the BSc degree in
Telecommunications from Institut Teknologi
Bandung (ITB), Indonesia in 1987. He also
received an MSc degree in Telematics (in 1994)
and a PhD in Multimedia Communication (in 2002)
from the University of Surrey, UK. He has been
with PT Telekomunikasi Indonesia since 1988 in
various engineering divisions, and he is currently
working in the TELKOM R&D Centre as a Senior
Manager of Service and Product R&D. Within the
Asia Pacific Telecommunity (APT) Wireless
Forum (AWF) he holds the responsibility of the
Convergence Working Group Chairman.
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 21
ISSN: 1942-9703 / © 2010 IIJ
Abstract—In this research work we have developed a tool and
a program that can be used to replace the behavior of a mouse. Our results have shown that it can be used successfully to replace a mouse that is usually operated by hand. The system we developed in this research can be used to help people with quadriplegia (paralyzed) to operate a computer. In order to be highly accessible and affordable, the tool we built should be inexpensive and can be purchased easily. Thus we have selected an input method using a series of LEDs and a webcam. There are two LED used on the circuit due to the need to have two light sources in order to replace the mouse behavior. The image captured by the webcam is then filtered using an image segmentation technique (thresholding). The first light source is used as the head-tilt detector that will be used as the replacement for the left-button and right-button of the mouse. The second light source is used as a head-motion detector, to replace the mouse movement. Our head movement tracking device uses two pieces of LEDs, wires, several resistors and energy source (battery).
Index Terms— head movement tracking device, image segmentation, mouse controlling, thresholding.
I. INTRODUCTION
person who suffers quadriplegia is unable move his or her arms and legs to operate a mouse and keyboard [7].
Therefore, in order for such a person to operate today’s computers there is a need for special tools to aid that person operating a computer.
Recently, there has been a number of special equipment and software that has been developed to help a people who suffer from quadriplegia to interact with a computer. However, most of these specialized equipment and software is difficult to obtain. The difficulty is mostly due to their high
FX. Ferdinandus, Tri Kurniawan Wijaya, and Indra Maryati are with the
Department of Computer Science, Sekolah Tinggi Teknik Surabaya, Surabaya 60284, Indonesia They can be contacted at email: {ferdi, tritritri}@stts.edu, and [email protected].
Gunawan is with the Department of Electrical Engineering, Faculty of Industrial Technology, Institut Teknologi Sepuluh Nopember, Surabaya 60111 Indonesia. He can be contacted at email: [email protected].
Edwin Seno Dwihapsoro is with the Department of Computer Science, Sekolah Tinggi Teknik Surabaya, Surabaya 60284 Indonesia.
prices (particularly for developing nations), the low availability of these instruments or items, and the regulations pertaining to the buying and selling of electronic goods across states. One example of a detector that recently became available is the “Ocular Mouse” which is an eye muscle detector. However, the tool is only available to certain communities and it is expensive. There is also a head movement tracking device called TrackIR that is relatively well known compared to other tracer devices. This tool is well known for its primary function to play games. However, such a tool that can detect head movements can also be used to help people who suffer from quadriplegia to operate a computer. However, similar to other head movement tracking devices on the market, the price of this tool is also relatively expensive and therefore unaffordable the majority of people in developing nations, including Indonesia.
II. IMAGE SEGMENTATION
Thresholding is a simple method of image segmentation. A thresholding method allows the creation of a binary image from a gray scale image [2]. A binary image is an image in which every pixel can have of one of two possible values. The values that are usually chosen are the values that represent black and white, although the values that represent other colors can also be used.
In the binary image, a pixel color value is used as the foreground/object color while the value of the other colors is used as the background. The ultimate purpose of the threshold method is to simplify the representation of the image so that the image can be more easily analyzed.
The reason a thresholding method was chosen is to allow us to more easily detect and differentiate between the features of tracked objects and the background. Since the thresholding method is a simple method, it is expected that required computational processes will not overload the system and that the basic specifications required for the system can be as minimum as possible.
EnsoTracker: Mouse Controller Device using Head Movement
Gunawan Institut Teknologi Sepuluh Nopember
FX. Ferdinandus, Tri Kurniawan Wijaya, Indra Maryati and Edwin Seno Dwihapsoro
Sekolah Tinggi Teknik Surabaya
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In this projecstem instead oason was becae movement, ailable tools. veloped systemd to develop a Eye movemennerally have aactical for useovement tracki
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INT
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ATED WORK
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ISSN: 194
DEVICE
as reference m. The goal is
accessibility aa benchmark ng others:
system to be usf the compone
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ESIA JOURNAL
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gure 1: Some rec
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The general futhose we develp people with
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SYSTEM ARCH
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unctions of theeloped in this rh paralysis qua
r Mouse doeses a special sensors are placedsix (6) sensors user's head. Thapable of pro
movement. ThePC with an Ris about US$ 2ople in develop
HITECTURE
ystem is shownfrom the head system emits livice.
WAN ET AL.
ess accurate. ality camera. is also bulky e movement his tool was
companies, bit systems, .
vices.
igure 1 (b) is States in the ghtning II).
with a video l large, and
e from Brazil Ocular Mouse
of Brazilian o, who is a University of this tool was eitoza Brazil e device are research, and adriplegia to
not use any nsor that can d around the that need to
e sensors are cessing data e instrument
RS-232 serial 200 and thus ping nations.
n in Figure 2 marker tool.
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Light captureysically (by th
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Figure 2: B
In our systemicrosoft Directe operating syiver is a comprdware with trdware and sommunication mputer bus ismputer compmputers. DirectShow isveloped by Media streams orhelp software eaming mediaocedures, and frvices created 4]. Microsoft Dplications to ised on Windomcorders, webdeo input devedia files. The flexibility
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INT
deo input devsensor devicesa format reprermat). To be
aptures images ding on the spngs allowed.
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ISSN: 194
ice is process) and temporar
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stem
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device send dam data can be und card datars. program acce
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ments and actioments and actionoperate the nation of the oen keyboard cpplications suct.
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his research wusly explainedws DirectShoweo input deviceage. Figure 3 thd by a webcaby visual inpu
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VI. ENSOTRA
we named ourd, Ensotrackew API. The soue in the form ofhe programs obam via DSPac
ut devices usedWindows Direc
of Ensotracker
receives the orsed on the ltation method.
a grayscale ibinary image,user. In Enso
d binary image
put device. Fore it reachesssed before it
ge captured bys the image his research isses which canw). The imageelevant informput in the formn. In addition,can also be usenscreen keybhe program ansed to activatenet browser fo
ACKER
r system Ensoer gets the iurce image itsf a digital reprebtaining the orck234. The im
d in EnsotrackectShow API.
processes
riginal image, light intensity In this methoimage. Next, t using a thretracker, the trae) is done from
23
For example, the monitor, reaches the
y a webcam data from
a collection n be used to e is captured ation so that m of mouse , the mouse ed to activate board. The nd Windows e or operate
or surfing the
otracker. As image from elf is caught esentation of riginal image mage that is er systems is
the image is y using the od the initial the image is eshold value ansformation m the top-left
24
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proDuobjas notprodef(veis neximEn
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ordinate to botEnsotracker rogram transforuring the transfject pixel, the the first light t take further ocessed by thefault setting rertical). When another objectxt light source
mage acquired nsotracker prog
Figure 4: H
After the progrcond, the proowever Ensotrhen the light socause the progre input (see Fiad-tilt angle, wad position dennot be done we position and cptured image cssibility that te not of the hea
As can be seenflection of the e second light e angle θ, if the box 1 and box
θ = arctan ((X2
The above fore value of X ane formula abotween X and Y
ttom-right coorreceives the lrms the grayscformation procprogram takessource positioobject pixel p
e program has requires the dthe program ht pixel positione position. Thfrom the vide
gram is closed.
Head Movement
ram gets the fiogram can peracker cannot ource is more oram is designeigure 4). The fwhile the seco
etector. The reawith more thacondition of thcannot be knohe first light sad position mar
VII. ANGLE C
n in Figure 5, tfirst light soursource (box 2)
he known valux 2 (X1, X2, Y
2-X1) / (Y2-Y
rmula can leadnd Y of the boxove has a reY is at least 1.
INT
rdinate of the imlight source's cale image intocess, when the s the pixel posion. After that tositions until reached a certistance to be ad covered then, that positionhis process coeo input devic
Tracking Devic
irst light sourceerform the mperform the m
or less than twod to use two (2first light sourond light sourcason why the an two light sohe equipment aown. This is bsource positionrker tool, but is
CALCULATIONS
the angle θ is orce (box 1) of t). The formula ues are the X aY1, Y2) is:
1)) * 180/pi (1)
d to an error if x 1 and box 2. quirement thaSpecial attent
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ISSN: 194
mage. position as
o a binary imaprogram findsition and storethe program dothe image that
tain distance. T20 pixels do
e distance, if thn is stored as
ontinues until ce is stopped
ce Ensotracker
e position and mouse emulatimouse emulato sources. This2) light sourcesrce is used as ce is used as mouse emulat
ources is becaut the head marecause there in and the secos instead a nois
S
obtained from the triangle A aused to calcul
and Y position
)
we do not cheCalculations wat the differention also needs
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the on. ion s is s as the the ion use ker is a ond se.
the and late n of
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be givelead to convert degree, radians.
The mouse applicat
TestinInterneton a lin“www.glink.
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en to the diffe“division by
t degree to radbut the defa
.
Fi
testing of theclick, Interne
tions using Ensing the internt browser applnk. In the testgoogle.com” an
est the runninged a notepad
d we asked usthe on-screen ames similar tos user to movethe screen. In r edges/sides o
vent the ball fThe movable
and is controllbelow the scre
right, and uponagain. umber of reses in the abovespondents wer
nd were not allo
results of thecan help peo
hands or feetacker system
through the In
L
rence in the vzero” error. F
dians, because ault result of
igure 5: Angle C
VIII. TESTI
e system is doet browsing, asotracker. et browsing ilication, enteriting process, t
and the link use
g of other appliand a game cser to type thkeyboard). Ino Arkanoid, we a board or plthe game a ba
of the screen. from droppinge board is localed by the useeen. The user
n hitting the bo
spondents were test, providingre asked to usowed to use ei
e test allowedople browse tht. Thus it cancan help peo
nternet.
GUNAW
value of Y, beFormula 180/pwe need the vthe arctan ca
Calculation
ING
one on severaand the runni
is started by ing the URL, the URL used ed was the “Ab
ications using called “Smashie letters “ABC
n smashing gamwhich is a simplank to the righall bounces coThe object of
g down the boated on the boer to prevent this able to movard the ball bo
re asked to pg us with somese the Ensotraither hands or
d us to concluhe Internet wn also be conople with qua
WAN ET AL.
ecause it can pi is used to value of θ in alculation is
al cases: the ing of other
opening the and clicking was simply
bout Google”
Ensotracker, ing”. On the CDEFGHIJ” me, the user
ple game that ht and to the ontinually on f the game is ottom of the ottom of the he ball from ve the board
ounces up the
perform the e test results. acker system feet in a test
ude that the without using ncluded that adriplegia to
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ol.2/No.2 (2010)
The respondene or playing “spondents are thout any probe respondents flective boardshus from the redeed help peosides the Intern
IX.
In addition to this research
n be used as sition of the obwork correctl
plied to its opd the backgroing tracked. In this researvice that can rovement devicong potentialadriplegia. Hooduced by the e quality of theouse emulationFor the futurevelop more cod, better electrod others. In ad
mproved using ise easily and r a more refine
CoderSource.nehttp://www.codGonzalez, RafaImage ProcessinTopik Primary chttp://en.wikipeTopik Visible Shttp://en.wikipeRedação Terra, Hardware & Sohttp://tecnologia2008. Tania Orsi, Sciehttp://www.scieularmouse.htm.Quadriplegia - Qhttp://www.spinUN Enable - Rehttp://www.un.oMarket share fohttp://marketsha
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CONCLUSION A
creating the hwe also showthe detecting
bject/light. Holy there are sperating enviroound should b
rch, we have replace the mouce in an inexls primarily owever, the rvideo input dee tracking of thn. e developmentonvenient toolsonic cables, adddition, the liga more robustcan use a largd the movemen
REFER
et, Binary Image, dersource.net/csharel C. & Woods, Rng. Pearson Educacolor Wikipedia, edia.org/wiki/PrimSpectrum Wikipediedia.org/wiki/VisibBrasileiro cria mo
oftware, a.terra.com.br/inte
enceNET, encenet.com.br/bac 2008. Quadriplegia, nalinjury.net/quadrelationship betweeorg/disabilities/defor browsers, operatare.hitslink.com/reWork, http://wwwk/. 2008.
INT
fficulty in eitheame. When tryin the letters g the game “Serience problen by using th
e concluded thaand operate oithout using th
AND FUTURE W
ead movementwed that a thre
and trackingwever, in orde
some constrainonment. Notabbe darker than
succeeded in use input using
xpensive way. for people
resolution andvice is very strhe head movem
s of our systes for the usersdjustable ear poght positioningt algorithm thager image resolnt of the mous
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rp_color_image_toichard E., Thresho
ation. 2002, pp. 59
mary_color. 2008. ia, ble_Spectrum. 200ouse ocular para t
erna/0,,OI1124734
ckup/english/scien
riplegia.htm. 2008en Development anfault.asp?navid=35ting systems and seport.aspx?qprid=1
w.digitalmoviebox.c
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er opening a tying notepad, “ABCDEFGH
Smashing” whiems in operate mouse pointat the system cther applicatio
heir hands or fe
WORK
t tracking deviesholding methg method for er for this methnts that must bly ambient lin the object/li
implementingg a head trackThe device hsuffering fr
d image qualrongly influencments and by
em, the aim is, such as smalositioning handg process can at can handle lution that alloe pointer.
o_binary.aspx. 200olding. In Digital 5-611.
08. tetraplégicos - Ter
4-EI4801,00.html.
ncenews/ed_48/48_
8. nd Human Rights, 5&pid=33. 2008.earch engines, 10. 2008. com/mycamcar/ho
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[11] Dev200
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[13] MSDus/li
[14] Oren(APhttpeBa
[15] Tophttp
[16] Paghttp
[17] Thehttp
SIA JOURNAL
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vice Driver Wikipe8. y, Andrew C.; Dic
er Guide for the BBcrocomputer CentrDN, DirectShow dibrary/ms783323.anstein, David. “Qu
PI)". Computerworp://www.computerwasic&articleId=434pik Augmented Rep://en.wikipedia.orge 1 Introduction top://www.vwlowen.e DSPack Project. pp://www.progdigy.
GSTSdNwSSLIMA
FCTCTISTi
TdTtyDTDiTlst
ICTpTSLI
edia, http://en.wiki
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Gunawan receiveScience in 1991Technology in 20Surabaya, Indonedoctoral degree atNopember, in Surworking as Vice DSenior Lecturer Surabaya. His reLanguage ProceIndonesia), ArtificMining, Neural Algorithm.
F. X. FerdinanduComputer ScienceTeknik Surabaya, Computer SciencTeknologi SepulIndonesia. He is cuStudent Affairs anTinggi Teknik Sinclude Networkin
Tri Kurniawan degree in ComputTinggi Teknik Surtime computer labyear of study in Department of CoTinggi Teknik SuDecember 2007. Cin the faculty of ITechnology. His rlearning, neural systems, intelligentheory.
Indra Maryati rComputer ScienceTeknik Surabayapursuing a maTechnology at Surabaya. AdditioLecturer at the SekIndonesia.
ipedia.org/wiki/De
Holmes, Mark A. er. Cambridge, UK443. tp://msdn.microso
cation Programmin
/article.do?comma
d_reality. 2008.
/page01.htm. 2008
2008.
ed the S.Kom degr1 and M.Kom 005 from Sekolahsia. Currently het the Institut Tek
rabaya, Indonesia. Dean of Academi
at Sekolah Tsearch interests i
essing (especiallycial Intelligence, Network, Fuzzy
us received the S.e in 1992 from Indonesia, and the
ce in 1997 fromluh Nopember, urrently working and a Senior Lectu
Surabaya. His resng, and Data Encry
Wijaya receivedter Science in 200rabaya, Indonesia.
boratory assistant sthis university.
omputer Science,urabaya, as a facuCurrently, he is a gInformatics, Viennresearch interests i
networks, decnt agent, data min
received the S.Ke in 2010 from thea, Indonesia. Custer’s degree ithe Sekolah T
onally, she is workkolah Tinggi Tekn
25
evice_driver.
The Advanced K: Cambridge
ft.com/en-
ng Interface
and=viewArticl
8.
ree in Computer in Information
h Tinggi Teknik e is pursuing a knologi Sepuluh
He is currently ic Affairs and a Tinggi Teknik include Natural y in Bahasa Data and Web
y, and Genetic
.Kom degree in Sekolah Tinggi e M.T degree in m the Institut
in Surabaya, as Vice Dean of urer at Sekolah search interests yption.
d his bachelor 07 from Sekolah . He was a full-since his second
He joined the at the Sekolah
ulty member in graduate student na University of include machine cision support ning, and game
Kom degree in Sekolah Tinggi
urrently she is in Information Tinggi Teknik king as a Junior nik Surabaya, in
26
Edwin Sendegree in CoTinggi Tekndegree in EcWijaya Putrathe IT ManaContactor Co
INT
o Dwihapsoro reomputer Science inik Surabaya, Indconomics in 2008 a, Surabaya. He is
agement division aompany.
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eceived the S.Kin 2008 from Sekodonesia, and the
from the Universs currently workint Magna Karsa Mu
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sitas g in ulya
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L GUNAWWAN ET AL.
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL
ISSN: 1942-9703 / © 2010 IIJ
27
Abstract—Sanata Dharma University has been developing
a web based learning management system, named Exelsa
(Experiential E-Learning of Sanata Dharma University)
since 2008. Exelsa provides a number of learning facilities,
including an online discussion board, lecture materials,
course content management, a course calendar/schedule,
information announcement, online test, auto-marked
quizzes and exams. The research aims to analyze the most
dominant factors that underlie the acceptance and use of
Exelsa among the students of Sanata Dharma University
by adopting UTAUT model (Venkatesh et al. in 2003). The
data is gathered by distributing questionnaires to many
course members and by collecting data from the database
of Exelsa. After the data was tabulated then it was
analyzed using Partial Least Square (PLS). The results
shows that performance expectancy, social influence and
facilitating conditions have significant influence (α = 0.05)
on behavioral intention. It was also shown from two
predictor of use behavior (behavioral intention and
facilitating conditions), the behavioral intention has a
significant influence on use behavior. The research model
explained 27.3% of the variance in user intention to use
Exelsa. Based on this results, it can be concluded that the
UTAUT model is insufficient in explaining students’
intentions in using LMS.
Index Terms—Exelsa, LMS, PLS, UTAUT.
I. INTRODUCTION
ejak diperkenalkannya Learning Management System
(LMS), cara staf pengajar bekerja telah berubah pesat.
Apakah pelajaran diajarkan sepenuhnya online atau
apakah menggunakan paduan pendekatan tradisional dan
online, sebagian besar staf pengajar di universitas harus
merancang dan mengembangkan materi online, membuat dan
memelihara situs web pembelajaran dan LMS telah menjadi
sarana komunikasi yang dominan dengan siswa bagi banyak
staf pengajar [12]. Definisi dari LMS adalah infrastruktur dimana e-Learning
dapat dibangun dan diantarkan [10]. Sementara e-Learning
adalah proses pembelajaran yang memanfaatkan teknologi
I Gusti Nyoman Sedana adalah staf quality assurance di PT. Sigma Cipta
Caraka. Penulis dapat dihubungi melalui email, [email protected].
St. Wisnu Wijaya adalah Dosen Teknik Infromatika Universitas Sanata
Dharma Yogyakarta. Penulis dapat dihubungi di [email protected].
informasi dan komunikasi secara sistematis dengan mengintegrasikan semua komponen pembelajaran, termasuk
interaksi pembelajaran lintas ruang dan waktu, dengan kualitas
yang terjamin [17]. Pengembangan sistem pembelajaran
berbasis digital (LMS) merupakan salah satu kegiatan untuk
meningkatkan kualitas pembelajaran di Universitas Sanata
Dharma [18]. Kegiatan ini diadakan untuk mendukung salah
satu sasaran jangka pendek Universitas Sanata Dharma yaitu,
peningkatkan efisiensi dan produktifitas. Untuk mencapai
sasaran ini, sejak tahun 2008 Universitas Sanata Dharma telah
mengembangkan dan mengimplementasikan sebuah LMS
yang diberi nama Experiential E-Learning of Sanata Dharma
University, yang lebih dikenal dengan nama Exelsa [13]. Proyek ini diikuti oleh kebijakan Universitas dengan
mengadakan pelatihan penggunaan Exelsa dan pengembangan
materi pembelajaran digital bagi para dosen [18]. Disamping
itu, juga dilakukan sosialisasi mengenai keberadaan Exelsa
melalui penyebaran brosur-brosur di lingkungan Universitas
Sanata Dharma.
Sebagai sebuah media pembelajaran, Exelsa harus dapat
diterima dan digunakan oleh para penggunanya sehingga
dapat meningkatkan produktivitas. Salah satu model terbaru
untuk menjelaskan penerimaan pengguna (user acceptance)
dalam bidang Sistem Informasi dikembangkan oleh Venkatesh, dkk. [20]. Model ini diberi nama the Unified
Theory of Acceptance and Use of Technology (UTAUT).
UTAUT menunjukkan bahwa niat untuk berperilaku
(behavioral intention) dan perilaku untuk menggunakan suatu
teknologi (use behavior) dipengaruhi oleh persepsi orang-
orang terhadap ekspektansi kinerja (performance expectancy),
ekspektansi usaha (effort expectancy), pengaruh sosial (social
influence) dan kondisi yang membantu (facilitating
conditions) yang dimoderatori oleh jenis kelamin (gender),
usia (age), pengalaman (experience) dan kesukarelaan
(voluntariness). Teori ini menyediakan alat bagi para manajer
untuk menilai kemungkinan keberhasilan pengenalan teknologi baru dan membantu mereka memahami penggerak
penerimaan dengan tujuan untuk proaktif mendesain
intervensi (termasuk pelatihan, sosialisasi, dll.) yang
ditargetkan pada populasi pengguna yang mungkin cenderung
kurang untuk mengadopsi dan menggunakan sistem baru [20].
Model asli UTAUT divalidasi menggunakan data yang
dikumpulkan dari lingkungan non akademik. Meskipun
demikian, beberapa peneliti telah menerapkan model ini di
lingkungan akademik. Dasgupta, dkk. [4] menerapkan model
UTAUT untuk memahami persepsi mahasiswa terhadap
UTAUT Model for Understanding Learning
Management System
I Gusti Nyoman Sedana
Universitas Sanata Dharma Yogyakarta, Indonesia
St. Wisnu Wijaya
Universitas Sanata Dharma Yogyakarta, Indonesia
S
28 INTERNETWORKING INDONESIA JOURNAL SEDANA & WIJAYA
ISSN: 1942-9703 / © 2010 IIJ
penerimaan dan penggunaan Case tools. Hasilnya effort
expectancy tidak berpengaruh terhadap behavioral intention.
Marchewka, dkk. [11], Sedana dan Wijaya [14] juga
melaporkan adanya perbedaan dengan model asli UTAUT
ketika mereka menerapkan UTAUT di lingkungan akademik.
Menurut laporan Marchewka, dkk. [11], performance expectancy tidak memiliki hubungan yang signifikan dengan
behavioral intention. Sementara dalam laporan studi
pendahuluan yang dilakukan oleh Sedana dan Wijaya [14],
effort expectancy tidak memiliki hubungan yang signifikan
dengan behavioral intention. Sedana dan Wijaya [14] juga
melaporkan bahwa facilitating conditions memiliki hubungan
yang signifikan dengan behavioral intention.
Meskipun hasil penelitian-penelitian dengan model
UTAUT di lingkungan akademik sedikit berbeda dengan
model aslinya, kami percaya dengan mengadopsi model
UTAUT akan membantu kami untuk memahami faktor-faktor
yang mendasari penerimaan dan penggunaan Exelsa. Namun untuk menyesuaikan dengan situasi dan kondisi lingkungan
penelitian, dalam penelitian ini kami tidak menggunakan
variabel moderator.
II. EXELSA
Experiential E-Learning of Sanata Dharma University
(Exelsa) adalah sebuah Learning Management System (LMS)
berbasis web yang dikembangkan untuk meningkatkan kualitas pembelajaran dan pendidikan di Universitas Sanata
Dharma [13]. Sebagai sebuah LMS, Exelsa menyediakan
sejumlah fasilitas pembelajaran seperti, tugas online, tes
online, bahan kuliah, chating, menjawab kuesioner, melihat
pengumuman, forum mata kuliah, kalender kegiatan dan
sebagainya. Lebih lanjut, Exelsa diharapkan dapat
meningkatkan efektifitas dan kualitas komunikasi
pembelajaran dengan pendekatan knowledge management
diantara berbagai pihak seperti dosen, mahasiswa, program
studi, biro administrasi akademik, penyedia media
pembelajaran serta berbagai pihak lainnya yang
berkepentingan [13]. Penggunaan Exelsa di Universitas Sanata Dharma tidak
bersifat wajib. Meski demikian, beberapa jurusan seperti,
Teknik Informatika, Teknik Mesin, Teknik Elektro,
Pendidikan Akuntansi dan Bimbingan dan Konseling telah
memanfaatkannya. Para mahasiswa dari jurusan-jurusan ini
memiliki pengalaman yang relatif sama dalam menggunakan
Exelsa. Usia mereka pun tidak terpaut jauh antara satu dengan
yang lainnya. Alasan-alasan inilah yang menyebabkan kami
tidak menggunakan variabel moderator dalam penelitian ini.
III. UTAUT
The Unified Theory of Acceptance and Use of Technology (UTAUT) merupakan salah satu model penerimaan teknologi
terkini yang dikembangkan oleh Venkatesh, dkk. [20].
UTAUT mensintesis elemen-elemen pada delapan model
penerimaan teknologi terkemuka untuk memperoleh kesatuan
pandangan mengenai penerimaan pengguna. Kedelapan teori
terkemuka yang disatukan di dalam UTAUT adalah theory of
reasoned action (TRA), technology acceptance model (TAM),
motivational model (MM), theory of planned behavior (TPB), combined TAM and TPB, model of PC utilization (MPTU),
innovation diffusion theory (IDT) dan social cognitive theory
(SCT). UTAUT terbukti lebih berhasil dibandingkan
kedelapan teori yang lain dalam menjelaskan hingga 70 persen
varian niat (intention) [14].
Model UTAUT memiliki empat konstruk yang memainkan
peran penting sebagai determinan langsung dari behavioral
intention dan use behavior yaitu, performance expectancy,
effort expectancy, social influence, dan facilitating conditions
(definisinya dapat dilihat pada tabel 1). Disamping itu terdapat pula empat moderator: gender, age, voluntariness, dan
experience yang diposisikan untuk memoderasi dampak dari
konstruk-konstruk pada behavioral intention dan use behavior.
Gambar 1. Model UTAUT.
Sumber: Venkatesh, dkk. [20].
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ISSN: 1942-9703 / © 2010 IIJ
29
Gambar 1 menampilkan keterkaitan antara determinan-
determinan dan moderator-moderator ini.
IV. METODOLOGI
Penelitian ini menggunakan model UTAUT yang telah
dimodifikasi sedemikian rupa hingga menjadi lebih sederhana
seperti terlihat pada gambar 2.
Teknik pengambilan data dalam penelitian ini adalah
survei dan pengambilan data melalui basis data Exelsa.
Pengambilan sampel menggunakan metode purposive
sampling dengan kriteria: (1) kelas kuliah yang dipilih adalah kelas yang memanfaatkan Exelsa dalam proses pembelajaran,
(2) responden adalah mahasiswa Universitas Sanata Dharma
yang mengikuti kuliah yang telah ditentukan pada saat
penelitian. Data yang diperoleh dari survei adalah data primer
sedangkan, pengambilan data perilaku penggunaan Exelsa dari
basis data menghasilkan data sekunder. Data primer adalah
data yang diperoleh langsung di lapangan. Sedangkan data
sekunder adalah data yang diperoleh dari sumber-sumber yang
telah ada [6].
Instrumen penelitian yang dipakai adalah skala UTAUT.
Skala UTAUT diadaptasi dari skala penelitian Venkatesh
dkk.[20]. Skala ini mencakup lima aspek yaitu, performance expectancy (PE), effort expectancy (EE), social influence (SI),
facilitating conditions (FC), dan behavioral intention (BI).
Model penilaian pernyataan terdiri dari lima alternatif jawaban
yang diberi skor berkisar dari 1 sampai 5. Klasifikasi
jawabannya adalah Sangat Tidak Setuju (STS), Tidak Setuju
(TS), Netral (N), Setuju (S) dan Sangat Setuju (SS).
Sementara itu, konstruk use behavior diukur menggunakan
frekuensi login mahasiswa dalam 5 minggu. Frekuensi login
diperoleh dengan cara mengolah data dari basis data Exelsa
milik Lembaga Penjaminan Mutu Universitas Sanata Dharma.
Sejumlah 232 mahasiswa dari berbagai program studi mengisi kuesioner, dari jumlah tersebut 214 kuesioner
dinyatakan layak untuk dianalisis sedangkan sisanya tidak
layak untuk dianalisis karena tidak valid. Pengambilan data
kemudian dilanjutkan dengan mengambil data dari basis data
Exelsa berdasarkan nomor induk mahasiswa (NIM) yang telah
mengisi kuesioner dengan valid. Data ini kemudian diolah
sehingga diperoleh hasil berupa frekuensi login mahasiswa
selama lima minggu. Rentang waktu lima minggu tersebut
merupakan masa dimana mahasiswa akan, sedang, dan sudah
menempuh ujian tengah semester.
V. HASIL PENELITIAN DAN PEMBAHASAN
Dari 214 responden yang telah mengisi kuesioner dengan valid, 107 responden adalah laki-laki dan sisanya adalah
perempuan. Data yang telah terkumpul kemudian ditabulasi
lalu dianalisis dengan menggunakan partial least square
(PLS) dengan bantuan perangkat lunak SmartPLS versi 2.0
M3. Chin (1998) dalam Henseler, dkk. [7] memberikan
kriteria untuk mengevaluasi model PLS dengan 2 langkah,
yang mencakup (1) evaluasi terhadap outer model dan (2)
evaluasi terhadap inner model.
A. Evaluasi Terhadap Outer Model
Outer model dengan indikator refleksif dievaluasi dengan
convergent dan discriminant validity dari indikatornya dan
composite reliability untuk blok indikator. Convergent
validity dinilai berdasarkan korelasi antara skor item dengan
skor konstruk yang dihitung dengan PLS [5], [7]. Tabel 2
memperlihatkan bahwa semua item memiliki loading factor di
atas 0,70 sehingga memiliki convergent validity yang baik [5],
[7].
Tabel 3
Composite
Reliability.
Composite
Reliability
BI 0,953
EE 0,847
FC 0,842
PE 0,869
SI 0,844
Gambar 2. Model Penelitian.
Tabel 4
Korelasi Variabel Laten dan Akar AVE.
Tabel 2
Loading Factor dari SmartPLS.
Performance
Expectancy
Effort
Expectancy
Social
Influence
Facilitating
Condition
Behavioral
Intention
Use
Behavior
30 INTERNETWORKING INDONESIA JOURNAL SEDANA & WIJAYA
ISSN: 1942-9703 / © 2010 IIJ
Discriminant validity dinilai dengan membandingkan nilai
square root of average variance extracted (akar kuadrat AVE)
setiap konstruk dengan korelasi antara konstruk dengan
konstruk lainnya dalam model. Dari tabel 4 dapat diketahui
bahwa nilai discriminant validity tergolong baik karena nilai
akar kuadrat AVE setiap konstruk lebih besar daripada nilai korelasi antara konstruk dengan konstruk lainnya dalam model
[5], [7].
Masing-masing konstruk dalam penelitian ini memiliki
reliabilitas yang tinggi. Hal ini dapat dilihat dari tabel 3
dimana composite reliability memiliki nilai yang tinggi (di
atas 0,80) [5], [7].
B. Evaluasi Terhadap Inner Model
Pengujian terhadap inner model dilakukan dengan melihat
nilai R-square yang merupakan uji goodness-fit model. Dari
tabel 5 dapat diketahui bahwa model penelitian ini
memberikan nilai R-square sebesar 0,273 dan 0,055. Hasil ini
dapat diinterpretasikan sebagai berikut, (1) besarnya varian
konstruk behavioral intention yang dijelaskan oleh varian
konstruk performance expectancy, effort expectancy, social
influence, dan facilitating conditions adalah 27,3%
sedangkan sisanya dijelaskan oleh variabel lain di luar yang diteliti. (2) besarnya varian konstruk use behavior (USE) yang
dijelaskan oleh varian konstruk facilitating conditions dan
behavioral intention adalah 5,5% sedangkan sisanya
dijelaskan oleh variabel lain di luar yang diteliti.
Tabel 5
R Square.
Variabel
Independen
Variabel
Dependen
R
Square
PE
BI 0,273 EE
SI
FC
FC USE 0,055
BI
Pengujian kemudian dilanjutkan dengan melihat signifikansi pengaruh variabel independen terhadap variabel
dependen dengan melihat nilai signifikansi statistik t dan nilai
koefisien parameter. Dari tabel 6 dapat diketahui bahwa
performance expectancy, social influence, dan facilitating
conditions memiliki pengaruh signifikan terhadap behavioral
intention karena nilai t hitung lebih besar daripada nilai t
tabel (1,97) pada taraf signifikansi sebesar 0,05. Behavioral
intention juga memiliki pengaruh signifikan terhadap use
behavior. Sementara effort expectancy tidak memiliki
pengaruh yang signifikan terhadap behavioral intention begitu
pula facilitating conditions tidak memiliki pengaruh yang
signifikan terhadap use behavior. Nilai koefisien parameter pengaruh performance
expectancy, social influence, dan facilitating conditions
terhadap behavioral intention secara berturut-turut adalah
0.147, 0.188, 0.322. Nilai koefisien parameter pengaruh
behavioral intention terhadap use behavior adalah 0,244.
C. Pembahasan
Temuan bahwa performance expectancy memberikan
pengaruh yang signifikan pada behavioral intention
mendukung hasil penelitian Venkatesh, dkk. [20], Dasgupta, dkk. [4]. Responden menganggap bahwa penggunaan Exelsa
dapat menolongnya untuk mendapatkan keuntungan-
keuntungan kinerja di pekerjaannya seperti, lebih mudah dan
cepat dalam mengerjakan dan menyelesaikan tugas-tugas
kuliah. Anggapan ini akan meningkatkan niatnya untuk
menggunakan Exelsa.
Tingkat kemudahan terkait penggunaan suatu sistem akan
mempengaruhi niat untuk menggunakan sistem tersebut [20],
[21]. Penelitian ini menemukan hasil yang berbeda yaitu,
tingkat kemudahan terkait penggunaan suatu sistem (effort
expectancy) tidak memberikan pengaruh yang signifikan pada behavioral intention. Dasgupta, dkk. [4], yang meneliti
tentang penerimaan pengguna terhadap Case Tools dalam
menganalisis dan mendesain suatu sistem, juga menemukan
pengaruh yang tidak signifikan seperti ini. Pengaruh yang
tidak signifikan ini dapat disebabkan karena Exelsa relatif
mudah digunakan dan berdasarkan hasil wawancara singkat
diperoleh informasi bahwa sebagian besar responden telah
memperoleh pengetahuan mengenai teknologi informasi dan
komunikasi sejak duduk di bangku Sekolah Menengah Atas.
Sehingga, responden tidak menganggap bahwa kemudahan
dalam menggunakan Exelsa akan mempengaruhi niatnya
untuk menggunakan Exelsa. Social Influence memiliki pengaruh yang signifikan
terhadap behavioral intention. Temuan ini mendukung hasil
penelitian Venkatesh, dkk. [20] dan dasgupta, dkk. [4]. Hasil
ini menunjukkan bahwa lingkungan sosial di sekitar responden
seperti teman kuliah, dosen, dan universitas mempengaruhi
niat mereka untuk menggunakan Exelsa.
Variabel facilitating conditions ternyata memiliki
pengaruh signifikan terhadap behavioral intention namun
tidak memiliki pengaruh yang signifikan terhadap use
behavior. Dasgupta, dkk. [4] juga menemukan bahwa
facilitating conditions memiliki pengaruh yang signifikan pada behavioral intention. Temuan ini berbeda dengan hasil
yang dilaporkan oleh Venkatesh, dkk. [20] dimana dalam
laporannya dikatakan bahwa facilitating conditions tidak
memiliki pengaruh yang signifikan terhadap behavioral
intention namun memiliki pengaruh yang signifikan terhadap
Tabel 6
Path Coefficients (Mean, STDEV, T-Values).
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL
ISSN: 1942-9703 / © 2010 IIJ
31
use behavior. Tampaknya ketersediaan infrastruktur teknik
dan organisasional mendukung niat untuk menggunakan
Exelsa tapi tidak mendukung perilaku penggunaan Exelsa.
Lebih lanjut, hasil ini dapat disebabkan oleh lingkungan
dimana penelitian ini diadakan. Penelitian ini diadakan di
lingkungan akademik sedangkan model asli UTAUT divalidasi dengan data yang diperoleh dari lingkungan non
akademik. Mengenai tidak signifikannya pengaruh facilitating
conditions terhadap use behavior dapat disebabkan karena
tidak digunakannya moderator experience dan age. Seperti
yang diungkapkan oleh Venkatesh, dkk. [20] konstruk
facilitating conditions apabila dimoderasi oleh experience dan
age maka akan memiliki pengaruh yang signifikan pada use
behavior. Namun karena responden dalam penelitian ini
tergolong dalam satu kelompok usia yang sama, dan semuanya
memiliki pengalaman yang relatif sama dalam menggunakan
Exelsa maka kedua moderator ini tidak digunakan. Hal inilah
yang dapat menyebabkan tidak signifikannya konstruk facilitating conditions dalam mempengaruhi use behavior.
Penelitian ini juga menemukan bahwa behavioral intention
memiliki pengaruh yang positif dan signifikan terhadap use
behavior. Temuan ini sesuai dengan konsep dasar dari model-
model penerimaan pengguna yaitu, niat untuk menggunakan
teknologi informasi akan mempengaruhi penggunaan
sebenarnya teknologi informasi tersebut [20].
VI. KESIMPULAN DAN SARAN
Berdasarkan hasil analisis empirik dan pembahasan yang
telah dilakukan dalam penelitian ini, maka dapat disimpulkan
bahwa (1) Variabel performance expectancy, social influence
dan facilitating conditions terbukti signifikan mempengaruhi
behavioral intention Mahasiswa Universitas Sanata Dharma
dalam menggunakan Exelsa. Sementara variabel effort
expectancy terbukti tidak signifikan. Variabilitas behavioral
intention dapat diterangkan 27,3% dengan menggunakan
variabel performance expectancy, social influence, effort
expectancy dan facilitating conditions. (2) Variabel behavioral intention terbukti signifikan mempengaruhi use behavior.
Sementara variabel facilitating conditions terbukti tidak
signifikan. Variabilitas use behavior dapat diterangkan 5,5%
dengan menggunakan variabel behavioral intention dan
facilitating conditions. (3) Hasil penelitian menunjukkan
bahwa model UTAUT belum bisa menjelaskan dengan baik
penerimaan dan penggunaan Learning Management System di
kalangan mahasiswa Universitas Sanata Dharma.
Agar pemanfaatan Exelsa lebih meningkat, peneliti
menyarankan hal-hal sebagai berikut (1) Cara mengajar
sebaiknya dirancang sedemikian rupa hingga, mahasiswa percaya bahwa penggunaan Exelsa akan secara positif
mempengaruhi performa belajarnya. (2) Para dosen sebaiknya
mendorong mahasiswanya untuk menggunakan Exelsa karena
mahasiswa percaya bahwa orang-orang yang penting baginya,
misalnya dosen menganggap bahwa dia sebaiknya
menggunakan Exelsa. (3) Universitas Sanata Dharma
sebaiknya memberikan dukungan yang memadai terhadap
ketersediaan infrastruktur teknis dan organisasional yang
mendukung penggunaan Exelsa.
UCAPAN TERIMA KASIH
Penulis mengucapkan terima kasih kepada pihak-pihak yang telah membantu sehingga penelitian ini dapat
diselesaikan, terutama kepada Ir. Ig. Aris Dwiatmoko, M.Sc.,
Prof. Diogenes de Souza Bido, dan Dr. Christian M. Ringle
atas diskusinya mengenai metode statistik. Terakhir, namun
tidak mengurangi rasa hormat, kami berterima kasih kepada
Puspaningtyas Sanjoyo Adi, S.T., M.T., PH Prima Rosa, S.Si.,
M.Sc., I Gusti Ketut Puja S.T., M.T., dan Damar Widjaja,
S.T., M.T., atas izinnya sehingga kami dapat mengambil data
untuk penelitian ini.
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I Gusti Nyoman Sedana received his Bachelor
degree from the Informatics Engineering
Department, University of Sanata Dharma,
Indonesia, in 2010. His previous research includes
user acceptance models. He is currently a quality
assurance staff member at the Sigma Cipta Caraka
Corporation.
St. Wisnu Wijaya received his Bachelor degree
from the Electrical Engineering Department,
Gadjah Mada University and his Master of
Informatics degree from the Department of
Informatics, Bandung Institute of Technology
(ITB), Indonesia. His current appointments are:
lecturer of Department of Informatics and
researcher at the Center for Information
Technology Studies, Sanata Dharma University,
Indonesia. Since 2009, he has been an expert staff
for the Institute for Migrant Workers. His research
interest is in the information system discipline,
especially the role of information technology in
social change. He has published numerous papers
in peer-reviewed journals and conference
proceeding. Mr St. Wisnu Wijaya has won
numerous research grants, including research grants
from the Government of Indonesia, Sanata Dharma
University and International Donors.
Vol.2/No.2 (2010) INTERNETWORKING INDONESIA JOURNAL 33
ISSN: 1942-9703 / © 2010 IIJ
Abstract—The Concept Hierarchy in attribute oriented
induction is a powerful tool for saving the knowledge hierarchy
in data, which will be then used to generalize mining rules for
data mining. Database design influences the performance
applications when reading records in database. When building
the database table the allocation of fields will be decided by the
lowest and the highest concept within the concept tree.
Additionally, the number of hierarchy concept levels in a concept
tree will decide the quantity of fields in the table. The number of
record tables will be decided by the number of the lowest
concepts in concept tree. For numeric values the treatment is
different. For efficiency reasons the number of created table
records will instead depend on the amount of concepts at the next
generalization. All the tables from concept trees will become
dimensional tables and the data table will become a fact table.
All these tables in fact create a star schema. The Star schema is
recognized as data warehouse schema for multidimensional
analysis, and will give value add for attribute oriented induction
for multidimensional purposes.
Index Terms—Data Mining, concept hierarchy, attribute
oriented induction, rule, database.
I. INTRODUCTION
HE attribute oriented induction method integrates a
machine learning paradigm – especially learning-from-
examples techniques [3] – with database operations, extracts
generalized rules from an interesting set of data and discovers
high level data regularities [13]. The attribute oriented
induction method has been implemented in a data mining
system prototype called DBMINER [16,17] which was
previously called DBLearn [12,14], and has been tested
successfully against a large relational database.
The attribute oriented induction approach was developed for
learning different kinds of knowledge rules such as
characteristic rules, discrimination or classification rules,
quantitative rules, data evolution regularities [15], qualitative
rules [9], association rules and cluster description rules [13].
Attribute oriented induction has the concept hierarchy as an
advantage, where a concept hierarchy as background
knowledge can be provided by knowledge engineers or
Manuscript received March 17, 2010.
Spits Warnars is a doctoral student at the Department of Computing and
Mathematics, Manchester Metropolitan University, John Dalton Building,
Chester Street, Manchester M15GD United Kingdom. (e-mail:
domain experts [8,10,13]. Concepts are ordered in a concept
hierarchy by levels from specific or low level concepts into
general or higher level concepts. Generalization is achieved
by ascending to the next higher level concepts along the paths
of concept hierarchy [11]. The most general concept is the null
description as the most specific concepts correspond to the
specific values of attributes in the database described as ANY.
The concept hierarchy can be balanced or unbalanced, but an
unbalanced hierarchy must then be converted to a balanced
one.
There are 3 Types of concept generalization on concept
hierarchy [6] and in [5] number (2)-(4) as 3 types of rule based
concept hierarchy and number (1) as a non rule based concept
hierarchy. These are:
1) Unconditional concept generalization: the rule associated
with the unconditional IS-A type rules. A concept is
generalized to a higher level concept because of the
subsumption relationship indicated in the concept
hierarchy.
2) Conditional/deductive rule generalization: the rule
associated with a generalization path as a deduction rule
where the type of rules is conditional and can only be applied to generalize a concept if the corresponding
condition can be satisfied. For example, form : A(x) Λ
B(x) C(x) has the meaning that for a tuple x, the
concept(attribute value) A can be generalized to concept
C if condition B can be satisfied by x. Or concept C can
be generalized if it can be satisfied by concept A and B.
3) Computational rule generalization: each rule is
represented by a condition which is value-based and can
be evaluated against an attribute or a tuple or the database
by performing some computation. The truth value of the
condition would then determine whether a concept can be
generalized via the path. 4) Hybrid rule-based concept generalization: a hierarchy can
have paths associated with all the above 3 different types
of rules. It has a powerful representation capability and is
suitable for many kinds of application.
An implementation needs a database for storing records,
while the application needs data mining tools for the user to
read records from database and get the rules in for
presentation. The database can be implemented using any kind
of database management system, such as Microsoft Access,
SQL Server, Oracle, MySQL and many other database
management systems. The application can be implemented
using any kind of language software, such as Java, Active
Star Schema Design for Concept Hierarchy in
Attribute Oriented Induction
Spits Warnars
Manchester Metropolitan University, United Kingdom
T
34 INTERNETWORKING INDONESIA JOURNAL WARNARS
ISSN: 1942-9703 / © 2010 IIJ
Server Pages, Visual Basic and others. The choice of the
database and application will depend on a number of factors,
including on the organizational rules, monetary resources, and
the technology.
In considering databases, one important factor is the
performance of the database system since it influences the
performance of the application as a whole. A good database
design will increase the application performance, while a bad
database design will reduce the application performance. An
additional factor is whether the database is normalized. On
one hand the normalization of a database provides for the best
performance and is useful for transactional processing systems
with input, edit and delete operations. On the other hand, an
unnormalized database will provide the best approach for
online analytical processing where records need only to be
read. Moreover, the number of SQL join operations will also
influence performance as a whole. Typically, more join
operations will need to be made in a normalized database
compared to an unnormalized database. The expert knowledge
in the area of database design contributes towards obtaining
the best design and performance. Additionally, a distributed
database can also be used for handling large distributed
concept hierarchies.
In this paper we transform the concept hierarchy into tables
resulting in a new database design. The concept tree will be
used as data input and the rules will be built based on the
queries [23,26,28].
Using queries to build rules presents an efficient mechanism
for understanding the mined rules ([22,25]). The use of the
threshold as a control over the maximum number of tuples
(within the target class in the final generalized relation) will
no longer be needed. Instead, group by operator in the SQL
Select statement will limit the final result generalization.
Setting different thresholds will generate different
generalized tuples (needed of global picture of induction).
Doing this repeatedly is time-consuming and tedious work
[27]. Instead, all the interesting generalized tuples as a
multiple rule can be generated for the global picture of
induction by using group by operator in the SQL Select
statement.
In converting the concept hierarchy into a database table
and in order to obtain the best database design, there are a
number of questions that need to be answered. These
questions include how to perform the conversion (from the
concept hierarchy into a table), how many tables will be
created and based on which criteria. By answering these
questions, we hope that a standard method will emerge for the
conversion of concept hierarchies into good database designs.
In the first instance the first step will be to explore how to
convert the non-rule based concept hierarchy (as an
unconditional concept hierarchy). Future work will address the
conversion of from rule based concept hierarchy.
In this paper we discuss only the conversion of the non-rule
based concept hierarchy into tables in the star schema design.
The implementation of the current and proposed attribute
oriented induction, including the differentiation between them,
can be found in [29].
II. CONVERTING FROM CONCEPT HIERARCHY INTO TABLE
In order to aid the discussion and provide a link between the
current work with our previous research, we will use the
concept hierarchy based on data examples found in [2,8].
Figure 1 shows an example of a concept hierarchy from
university database.
Burnaby
Victoria
...
Edmonton
...
Bombay
...
Nanjing
...
British Columbia
Alberta
...
India
China
...
Comp
Math
Physic
Biology
...
Literature
Music
History
...
Freshman
Sophomore
Junior
Senior
MA
MS
PhD
0.0-1.99
2.0-2.99
3.0-3.49
3.5-4.0
ANY(major)
ANY(Category)
ANY(Birthplace)
ANY(GPA)
Canada
Foreign
Undergraduate
Graduate
Poor
Average
Good
Excellence
Art
Science
Fig. 1. Example of a Concept hierarchy
Based on concept hierarchy in Figure 1 we will build
concept tree that represents a taxonomy of concepts of the
values in an attribute domain. The concept tree will be built
based on the most general concept which is described as ANY
in concept hierarchy. Based on Figure 1 there are four (4)
most general concepts with ANY, resulting in concept trees
[24]. These are:
1) (science, art) ANY(major)
2) (graduate, undergraduate) ANY(category)
3) (Foreign, Canada) ANY(birthplace)
4) (poor, average, good, excellence) ANY(GPA)
The dotted-line symbol (…) in Figure 1 shows the
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possibility of other concepts. For example, there is the
possibility to extend the width of concept tree by extending
the “Major” beyond “Science” and “Art”. Similarly, the
“Birthplace” is not limited to just only “Canada” and
“Foreign”.
For the database implementation all the concept trees will
be implemented as tables in the database. The concept tree for
“Major” will be implemented as the table entitled
hierarchy_major (see Table 1 and its explanation in Figure 2).
The lowest level concept tree for “Major” in Figure 2 like
comp, math, physics, biology, literature, music and history
become the first field name Major and has varchar data type
with length 15. The next and the last level concept tree for
major in figure 2 like science and art become the next field
name StudyProg and have varchar data type with length 15.
TABLE I
HIERARCHY_MAJOR TABLE
Field Name Type
Major varchar(15)
StudyProg varchar(15)
Field Name Type
Major varchar(15)
StudyProg varchar(15)
Fig. 2. The transformation of the concept tree for Major into hierarchy_major
table
For example, if there are 10 lowest level concepts in the
concept tree “Major” (Figure 2) then 10 records or tuples will
be created in the table hierarchy_major based on field
“Major” as the first field in that table. Each of the records will
fill the next field studyprog based on generalization the lowest
level concept tree major. For example for the record where the
major field is “Computing”, its next field studyprog will be
filled with “Science” because the computing as the lowest
level concept tree major in Figure 2 has a generalization into
Science. Table 2 is the result from the data from the concept
tree “Major” in Figure 2.
TABLE II
RECORDS FOR HIERARCHY_MAJOR TABLE
Major StudyProg
Computing Science
Math Science
Biology Science
Chemistry Science
Statistics Science
Physics Science
Music Art
History Art
Literal Arts Art
Literature Art
As another example, the concept tree for “Category” will be
implemented as table hierarchy_cat (see Table 3 and Figure
3). The lowest level concept tree for “Major” in Figure 3 such
as “Freshman”, “Sophomore”, “Junior”, “Senior”, “MS”,
“MA” and “PhD” become the first field named “Category”
and has varchar data type with length 15. The last level
concept tree for “Category” in Figure 3, such as
“Undergraduate” and “Graduate” becomes the next field name
“Study” and has varchar data type with length 15.
TABLE III
HIERARCHY_CAT TABLE
Field Name Type
Category varchar(15)
Study varchar(15)
Field Name Type
Category varchar(15)
Study varchar(15)
Fig. 3. The transformation of the concept tree for Category into hierarchy_cat
table
In Figure 3 there are seven (7) lowest level concepts from
concept tree “Category”, which will create seven (7) records
or tuples in table hierarchy_cat based on field Category as the
first field in the table. The records filling next field “Study”
will be based on the generalization the lowest level concept
tree “Category”. For example the record where the category
field contains “Freshman” will fill the next field (“Study”)
with “Undergraduate” because the concept “Freshman” as the
lowest level concept tree (in “Category” in Figure 3) has a
generalization into “Undergraduate”. Table 4 shows this based
on the data from concept tree “Category” in Figure 3.
TABLE IV
RECORDS FOR HIERARCHY_CAT TABLE
Category Study
Freshman undergraduate
Sophomore undergraduate
Junior undergraduate
Senior undergraduate
MS graduate
MA graduate
PhD graduate
The concept tree for “Birthplace” will be implemented as
the table hierarchy_birth (see Table 5 and Figure 4). The
lowest level concept tree for birthplace in Figure 4 (such as
Burnaby, Victoria, Edmonton, Bombay and Nanjing) will
become the first field name “Birthplace” and has a varchar
data type with length 15. The next level concept tree for
birthplace in Figure 4 (namely British Columbia, Alberta,
India and China) will become the next field name “City” and
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has varchar data type with length 20. Note that this tree is
different from the previous concept due to the fact that it has
three (3) levels. As such, the next and the last level concept
tree for birthplace in Figure 4 (namely Canada and Foreign)
will become the next field name “Country” and has a varchar
data type with length 10. Thus, the number of hierarchy levels
will determine the number of the fields that will be created. In
the case of the previous concept tree, because there are two (2)
hierarchy levels, therefore two fields will be created for each
concept tree. Similarly, since the concept tree “Birthplace” has
three (3) hierarchy levels, therefore three fields will be created
in the table.
TABLE V
HIERARCHY_BIRTH TABLE
Field Name Type
Birthplace varchar(15)
City varchar(20)
Country varchar(10)
Field Name Type
Birthplace varchar(15)
City varchar(20)
Country varchar(10)
Fig. 4. The transformation of the concept tree for Birthplace into
hierarchy_birth table
Following the previous example, there are eleven (11)
lowest level concepts in the concept tree “Birthplace” as
shown in Figure 4. This will create eleven records or tuples in
table hierarchy_birth based on field “Birthplace” as the first
field in the table. In each record the next field entry will be
based on the generalization on concept tree “Birthplace”.
TABLE VI
RECORDS FOR HIERARCHY_BIRTH TABLE
Birthplace City Country
Bombay India Foreign
Burnaby British Columbia Canada
Calgary Alberta Canada
Edmonton Alberta Canada
Nanjing China Foreign
Ottawa Ontario Canada
Richmond British Columbia Canada
Shanghai China Foreign
Toronto Ontario Canada
Vancouver British Columbia Canada
Victoria British Columbia Canada
For example the record where the birthplace field contains
the value “Bombay” will have the next field (“City”) filled
with the value “India” because the concept “Bombay” as the
lowest level in the concept tree “Birthplace” (see Figure 4) has
a generalization into the India concept. Furthermore, the next
field “Country” (which is the last field) with have the value
“Foreign” because the concept “India” has a generalization
into “Foreign” concept. Table 6 shows the resulting data from
concept tree “Birthplace” as shown in Figure 4.
The concept tree “GPA” will be implemented as table
hierarchy_gpa (see Table 7 and Figure 5). Different to the
previous concept trees, here there are a large range data for
hierarchy levels. For example, the generalization for concept
“Poor” comes from the value range between 0 and 1.99, and
thus there will be 199 values possible (covering from 0.00 to
1.99). For efficiency reasons we just record the first value and
last value in the range for each of hierarchy levels. As result,
we will add one field containing the last value implying that
“The number of hierarchy levels will decide the number of
fields will be created”. We use this notation here because
although the concept tree “GPA” (Figure 5) has only two
levels (and thereby creating two fields in the database), adding
199 records to each field will result in a table with a total of
400 records. Thus for efficiency reasons we treat concept trees
with numeric values differently [11,21,19,20]. Therefore, here
we have created only 3 fields with 4 records.
In the case of the GPA, the first field is GPA_start and will
have a range a values using the float(3,2) data type. Next is
field name GPA_fin that will also have a range a values using
the float(3,2) data type. The last field name “Range” will be
the same as the other concept trees where it has “the highest
level before the most general concept ANY is the last field”.
The field range has varchar data type with length 15.
TABLE VII
HIERARCHY_GPA TABLE
Field Name Type
GPA_start float(3,2)
GPA_fin float(3,2)
range varchar(15)
Fig. 5. The transformation of the concept tree for GPA into hierarchy_gpa
table
Because GPA concept tree in Figure 5 handles numeric
values, then the number of created records will not depend on
the number of concepts at the lowest level in concept tree.
Instead for efficiency it will depend on the number of concepts
at the next generalization. Now at the next generalization
(after the lowest level concept) there are four (4) concepts,
namely “Poor”, “Average”, “Good”, and “Excellent”.
Different to the other cases, the handling of numeric values in
the concept tree will be via specialization. For example the
first data at the level after the first low level is “Poor” and we
assign the GPA_start value of 0 and the GPA_fin with the
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value of 1.99. We do this also for the other fields. The result is
shown in Table 8 using the concept tree in Figure 5.
TABLE VIII
RECORDS FOR HIERARCHY_GPA TABLE
GPA_start GPA_fin range
0.0 1.99 Poor
2.0 2.99 Average
3.0 3.49 Good
3.5 4.0 Excellent
Based on the previous explanation, below are the summary
of the assumptions that we have used to convert a concept
hierarchy into a table:
1) The lowest level concept tree maps to the first field and
the highest level (before the most general concept ANY)
is mapped to the last field.
2) The number of hierarchy levels in a concept tree will
decide the number of fields in the table, with the
exception of numeric values for efficiency reasons.
3) The number of concepts at the lowest level in a concept
tree will become the number of records or tuples in the
table, with the exception of numeric values for efficiency
reasons.
4) For the efficiency handling numeric values in a concept tree, the number of created table records will not depend
on the number of concepts at the lowest level in concept
tree, but instead it will depend on the number of concepts
at the next generalization.
III. LOGICAL DATA MODEL
Based on data examples found in [2,8], Table 9 shows the
corresponding student table.
TABLE IX
STUDENT TABLE
Name Category Major Birthplace GPA
Anton M.A. History Vancouver 3.5
Andi Junior Math Calgary 3.7
Amin Junior Liberal arts Edmonton 2.6
Anil M.S. Physics Ottawa 3.9
Ayin Ph.D. Math Bombay 3.3
Amir Sophomore Chemistry Richmond 2.7
Acai Senior Computing Victoria 3.5
Abdi Ph.D. Biology Shanghai 3.4
Afun Sophomore Music Burnaby 3.0
Agung Ph.D. Computing Victoria 3.8
Ahing M.S. Statistics Nanjing 3.2
Akuan Freshman literature Toronto 3.9
All the tables that represent a concept hierarchy can be
connected to the student table. Figure 6 shows a class diagram
with the connectivity between tables. In the context of the
Data Warehouse concept, Figure 6 shows a star schema,
where the student table is viewed as a fact table and the other
tables from the concept tree are viewed as a dimensional table.
As a result, the multi dimensional concept in Data Warehouse
can be applied here, where the data can be roll up and drill
down and the data can be viewed in multiple dimensions with
concept slice, dice and pivot [4, 18]. The aggregate count
function and group-by-operator in the SQL Select statement
can represent the roll up process [1, 7].
Fig. 6. A Logical data model
To improve the performance the logical data model in
Figure 6, it can be changed to become one (1) table (as only
one fact table) as shown in Table 10. The data as the
representative all the data in Figure 6 is shown in Table 11 and
12. The performance can be improved by using unnormalized
tables. This is because using one table is faster rather than
using 5 tables through the decrease in the number of needed
Join operations. However, the limitation of using only one
fact table is that it poorly represents the concept hierarchy. For
efficiency needs these two options can be used together, where
queries will be directed at the single fact table and the concept
hierarchy is used as the basis for the logical data model as
exemplified by Figure 6.
TABLE X
ONE FACT TABLE
Student
Name
Category
Study
Major
Studyprog
Birthplace
City
Country
GPA
Range
TABLE XI
DATA IN ONE FACT TABLE
Name Category Study Major StudyProg
Anton MA graduate History art
Andi Junior undergraduate Math science
Amin Junior undergraduate Literal Arts art
Anil MS graduate Physics science
Ayin PhD graduate Math science
Amir Sophomore undergraduate Chemistry science
Acai Senior undergraduate Computing science
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Abdi PhD graduate Biology science
Afun Sophomore undergraduate Music art
Agung PhD graduate Computing science
Ahing MS graduate Statistics science
Akuan Freshman undergraduate Literature art
TABLE XII
CONTINUE DATA IN ONE FACT TABLE
Birthplace City Country GPA Range
Vancouver British Columbia Canada 3.5 Excellent
Calgary Alberta Canada 3.7 Excellent
Edmonton Alberta Canada 2.6 Average
Ottawa Ontario Canada 3.9 Excellent
Bombay India Foreign 3.3 Good
Richmond British Columbia Canada 2.7 Average
Victoria British Columbia Canada 3.5 Excellent
Shanghai China Foreign 3.4 Good
Burnaby British Columbia Canada 3 Good
Victoria British Columbia Canada 3.8 Excellent
Nanjing China Foreign 3.2 Good
Toronto Ontario Canada 3.9 Excellent
Another option for efficiency is by the appropriate coding
of the student data which can provide storage space savings,
better query performance and easier data management. The
following is an example of assigning codes to the field entries:
1) Coding for entries in the field studyprog: science 01, art
02.
2) Coding for entries in the field major: computing01,
Math02, Biology03, Chemistry04, statistics05, physics06, Music07, History08, Literal arts09,
Literature 10.
3) Coding for the field Study: undergraduate01,
graduate02.
4) Coding for the field Category: Freshman01,
Sophomore02, Junior03, Senior04, MS05,
MA06, PhD07.
5) Coding for the field Birthplace: Bombay01,
Burnaby02, Calgary03, Edmonton04,
Nanjing05, Ottawa06, Richmond07,
Shanghai08, Toronto09, Vancouver10, Victoria11.
6) Coding for the field City: India01, British
Columbia02, Alberta03, China04, Ontario05.
7) Coding for the field Country: Canada01, foreign02.
Note that the table representing hierarchy_gpa cannot be
coded because of its numeric data. Table 13 shows the coding
result for hierarchy_birth table, Table 14 for the hierarchy_cat
table, Table for the student table, and Table 16 shows the
coding result for hierarchy_major table.
TABLE XIII
CODING FOR HIERARCHY_BIRTH TABLE
BirthID Birthplace City Country
010102 Bombay India Foreign
020201 Burnaby British Columbia Canada
030301 Calgary Alberta Canada
040301 Edmonton Alberta Canada
050402 Nanjing China Foreign
060501 Ottawa Ontario Canada
070201 Richmond British Columbia Canada
080402 Shanghai China Foreign
090501 Toronto Ontario Canada
100201 Vancouver British Columbia Canada
110201 Victoria British Columbia Canada
TABLE XIV
CODING FOR HIERARCHY_CAT TABLE
CatID Category Study
0101 Freshman undergraduate
0102 Sophomore undergraduate
0103 Junior undergraduate
0104 Senior undergraduate
0205 MS graduate
0206 MA graduate
0207 PhD graduate
TABLE XV
CODING FOR STUDENT TABLE
name Category Major Birthplace
Anton 0206 0208 100201
Andi 0103 0102 030301
Amin 0103 0209 040301
Anil 0205 0106 060501
Ayin 0207 0102 010102
Amir 0102 0104 070201
Acai 0101 0101 110201
Abdi 0207 0103 080402
Afun 0102 0207 020201
Agung 0207 0101 110201
Ahing 0205 0105 050402
Akuan 0101 0210 090501
TABLE XVI
CODING FOR HIERARCHY_MAJOR TABLE
MajorID Major StudyProg
0101 Computing Science
0102 Math Science
0103 Biology Science
0104 Chemistry Science
0105 Statistics Science
0106 Physics Science
0207 Music Art
0208 History Art
0209 Literal Arts Art
0210 Literature Art
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IV. CONCLUSION
In order to convert a non-rule based concept hierarchy,
there are some guidance which can help in the conversion.
First, the lowest level concept is mapped to the first field and
the highest level before the most general concept ANY is
mapped to the last field. Secondly, the number of hierarchy
levels will determine the number of fields except for numeric
value (for efficiency reasons). Thirdly, the number of concepts
at the lowest level in concept tree will become the number of
records or tuples in the table (again with the exception of
numeric values for efficiency reasons). Finally, for the
efficiency handling numeric values in a concept tree, the
number of created table records will not depend on the number
of concepts at the lowest level in concept tree, but instead on
the number of concepts at the next generalization. From an
implementation perspective, there is the option of using one
fact table or several combined tables, and there is also the
option of using coding to improve efficiency and performance.
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Spits Warnars received his bachelor‟s degree in
Information System from the University of Budi
Luhur, Indonesia in 1995. He finished a master
degree in Information Technology from university
of Indonesia, in January 2007. Since 1995 he has
been a full time lecturer at the Information
Technology faculty, at University of Budi Luhur, in
Indonesia. He has also been an auxiliary lecturer
since January 2008 at the Bina Nusantara
University in Indonesia. Spits Warnars has been
completing his PhD degree in computer science at
Manchester Metropolitan University, UK, since
Sept 2008. His area of interest is data mining. He
has published 3 papers in international journals, 6
papers at international conferences, 10 papers in
Indonesian journals, and 7 papers at national
conferences in Indonesia. He has been an ACM
student member since 2008. He has been a reviewer
for the World Scientific and Engineering Academy
and Society since 2006. Since July 2010 he has
been on the editorial board of the Journal of
Computing and Applications (JCA), International
Association for Computer Scientists and Engineers
(IACSE) and Journal of Global Research in
Computer Science (JGRCS).
Internetworking Indonesia JournalThe Indonesian Journal of ICT and Internet Development
ISSN: 1942-9703
About the Internetworking Indonesia Journal
The Internetworking Indonesia Journal (IIJ) was established out of the need to address the lack of an Indonesia-wide independent academic and professional journal covering the broad area of Information and Communication Technology (ICT) and Internet development in Indonesia.
The broad aims of the Internetworking Indonesia Journal (IIJ) are therefore as follows:
Provide an Indonesia-wide independent journal on ICT• : The IIJ seeks to be an Indonesia-wide journal independent from any specific institutions in Indonesia (such as universities and government bodies). Currently in Indonesia there are numerous university-issued journals that publish papers only from the respective universities. Often these university journals experience difficulty in maintaining sustainability due to the limited number of internally authored papers. Additionally, most of these university-issued journals do not have an independent review and advisory board, and most do not have referees and reviewers from the international community.
Provide a publishing venue for graduate students• : The IIJ seeks also to be a publishing venue for graduate students (such as Masters/S2 and PhD/S3 students) as well as working academics in the broad field of ICT. This includes graduate students from Indonesian universities and those studying abroad. The IIJ provides an avenue for these students to publish their papers to a journal which is international in its reviewer scope and in its advisory board.
Improve the quality of research & publications on ICT in Indonesia• : One of the long term goals of the IIJ is to promote research on ICT and Internet development in Indonesia, and over time to improve the quality of academic and technical pub-lications from the Indonesian ICT community. Additionally, the IIJ seeks to be the main publication venue for various authors worldwide whose interest include Indonesia and its growing area of information and communication technology.
Provide access to academics and professionals overseas• : The Editorial Advisory Board (EAB) of the IIJ is intentionally com-posed of international academics and professionals, as well as those from Indonesia. The aim here is to provide Indonesian authors with access to international academics and professionals who are aware of and sensitive to the issues facing a develop-ing nation. Similarly, the IIJ seeks to provide readers worldwide with easy access to information regarding ICT and Internet development in Indonesia.
Promote the culture of writing and authorship• : The IIJ seeks to promote the culture of writing and of excellent authorship in Indonesia within the broad area of ICT. It is for this reason that the IIJ is bilingual in that it accepts and publishes papers in English and Bahasa Indonesia. Furthermore, the availability of an Indonesia-wide journal with an international advisory board may provide an incentive for young academics, students and professionals in Indonesia to develop writing skills appropriate for a journal. It is hoped that this in-turn may encourage them to subsequently publish in other international journals in the future.
Focus & Scope: The Internetworking Indonesia Journal (IIJ) aims to become the foremost publication for practitioners, teachers, researchers and policy makers to share their knowledge and experience in the design, development, implementation, and the man-agement of ICT and the Internet in Indonesia.
Topics of Interest: The journal welcomes and strongly encourages submissions based on interdisciplinary approaches focusing on ICT & Internet development and its related aspects in the Indonesian context. These include (but not limited to) information technology, communications technology, computer sciences, electrical engineering, and the broader social studies regarding ICT and Internet development in Indonesia. A list of topics can be found on the journal website at www.InternetworkingIndonesia.org.
Open Access Publication Policy: The Internetworking Indonesia Journal provides open access to all of its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. This follows the philosophy of the Open Journal Systems (see the Public Knowledge Project at pkp.sfu.ca). The journal is published electronically (PDF format) and there are no subscription fees. Such access is associated with increased readership and increased citation of an author’s work.
Internetworking Indonesia JournalISSN: 1942-9703
www.InternetworkingIndonesia.org