tts report aks

8/19/2019 TTS Report Aks

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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare 1

Chapter 1

Introduction

People are currently surrounded by technology, which tries to increase their uality of life

and facilitate the daily acti!ities" #n addition, the continuous ad!ancement in mobile

computing makes it possible to obtain information about the conte$t and also to react

physically to it, in more inno!ati!e ways" Howe!er, there are situations, where technology is

difficult to be handled or people ha!e lack of knowledge to use it" %or these reasons, ambient

intelligence &'m#( tries to adapt the technology to the people)s needs by proposing three

basic concepts* ubiuitous computing, ubiuitous communication, and intelligent user

interfaces" #n order to reach this ob+ecti!e, it is necessary to de!elop new frameworks and

models to allow access to functionalities, regardless of time and location restrictions"

This report describes a telemonitoring system aimed at impro!ing healthcare and

assistance to dependent people at their homes" This system makes use of the Services laYers

over Light PHysical devices &S-PH( platform" S-PH is based on a ser!ice.oriented

architecture &S/'( model for integrating heterogeneous wireless sensors networks &WSNs(

into 'm# systems" S-PH focuses on distributing the systems) functionalities into

independent functionalities &i"e", ser!ices(" This model pro!ides a fle$ible distribution of

resources and facilitates the inclusion of new functionalities in highly dynamic en!ironments"

1.1 Ambient Intelligence:

#n computing, ambient intelligence &AmI( refers to electronic en!ironments that are

sensiti!e and responsi!e to the presence of people" 'mbient intelligence is a !ision on the

future of consumer electronics, telecommunications and computing that was originallyde!eloped in the late 100s for the time frame 21322" #n an ambient intelligence world,

de!ices work in concert to support people in carrying out their e!eryday life acti!ities, tasks

and rituals in easy, natural way using information and intelligence that is hidden in the

network connecting these de!ices" 's these de!ices grow smaller, more connected and more

' P S 4ollege of 5ngineering 6ept" of #S5 212.217


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integrated into our en!ironment, the technology disappears into our surroundings until only

the user interface remains percei!able by users"

1.2 Service Oriented Architecture*

#n software engineering, a service-oriented architecture &SOA( is a style of software

architecture for designing and de!eloping software in the form of interoperable ser!ices"

These ser!ices ha!e well.defined business functionalities that are built as software

components &discrete pieces of code and8or data structures( which can be reused for

different purposes" S/' design principles are used during the phases of systems

de!elopment and integration"

S/' generally pro!ides a way for consumers of ser!ices, such as web.based

applications, to be aware of a!ailable S/'.based ser!ices" %or e$ample, se!eral disparate

departments within a company may de!elop and deploy S/' ser!ices in different

implementation languages9 their respecti!e clients will benefit from a well.defined interface

to access them" :;- is often used for interfacing with S/' ser!ices"


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Chapter 2

"istor$

5$cessi!e centrali>ation of ser!ices negati!ely affects the systems) functionalities,

o!ercharging, or limiting their capabilities" 4lassical functional architectures are

characteri>ed by trying to find modularity and a structure oriented to the system itself"

;odern functional architectures like S/', consider integration and performance aspects that

must be taken into account when functionalities are created outside the system" 'n S/'.

based system is a network of independent ser!ices, machines, the people who operate, affect,

use, and go!ern those ser!ices, as well as the suppliers of euipment and personnel to these

people and ser!ices" The term ser!ice can be defined as a mechanism that facilitates the

access to one or more functionalities &e"g", functions, network capabilities, etc"("

The S/' model is aimed at the interoperability between different systems,

distribution of resources, and the lack of dependency of programming languages" Ser!ices

are linked by means of standard communication protocols that must be used by applications

in order to share resources in the ser!ices network" The compatibility and management of

messages that the ser!ices generate to pro!ide their functionalities is an important and

comple$ element in any of these approaches" ' distributed architecture pro!ides more

fle$ible ways to mo!e functions to where actions are needed, thus obtaining better responses

at e$ecution time, autonomy, ser!ices continuity, and superior le!els of fle$ibility and

scalability than centrali>ed architectures" Unfortunately, the difficulty in de!eloping a

distributed architecture is higher" This way, it is necessary to ha!e a more comple$ system

analysis and design, which implies more time to reach the implementation stage"

'm#.based de!elopments will reuire the use of se!eral sensors and actuatorsstrategically distributed in the en!ironment" This pro!ides the systems with conte$t.aware

capabilities in order to change its beha!ior automatically" #t is possible to make a difference

between sensor networks* wired and wireless" There are se!eral technologies for creating

wired sensors networks, such as :1, -on Works, or ?N:" Howe!er, wired networks are not

as fle$ible as WSNs and reuire more infrastructural support" /n the other hand, wireless



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare @

technologies enable easier deployments than the wired ones, a!oiding the need of wiring

homes or hospitals and decreasing the costs, and drawbacks of the setup phase" The AigBee

standard allows operating in the freuency range belonging to the radio band known as

industrial, scientific, and medical S;(, especially in the CDC ;H> band in 5urope, the 01E

;H> in the U"S"'", and the 2"@ FH> in almost all o!er the world" The underlying #555

C2"1E"@ standard is designed to work with low.power and limited computational resources

nodes" AigBee incorporates additional network, application, and security layers o!er the

C2"1E"@ standard" The AigBee standard allows up to DE E7@ nodes connected in a star, tree,

or mesh topology network" 'nother standard to deploy WSNs is Bluetooth" This standard

allows multiple wireless personal 'rea networks &WP'N( and wireless body area networks

&WB'N( applications for interconnecting mobile phones, earphones, personal computers,

printers, etc" Bluetooth operates also in the #S; 2"@ FH> band" #t allows creating star

topology networks of up to eight de!ices in which one of them acts as master and the rest as

sla!es" Se!eral Bluetooth networks can be interconnected by means of Bluetooth de!ices that

belong simultaneously to two or more networks, creating more e$tensi!e networks"

'lthough there are plenty of options for creating WSNs, the main problem is the

difficulty for integrating de!ices from different technologies in a single network" #n addition,

the lack of a common architecture may lead to additional costs due to the necessity of deploying nontransparent interconnection elements between networks" ;oreo!er, the

de!eloped elements &e"g", de!ices( are too dependent on the application to which they belong,

thus complicating their reutili>ation" Some de!elopments try to reach the de!ices integration

by implementing middleware layers as reduced !ersions of !irtual machines &e"g", Suawk

e or more costly miniaturi>ation" These drawbacks are !ery important

regarding WSNs, as it is essential to deploy applications with reduced resources and low

infrastructural cost, especially in home care scenarios" The S-PH platform integrates an

S/' approach for facilitating the distribution and management of resources &i"e", ser!ices(

into heterogeneous WSNs"



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare E

There are se!eral attempts to integrate WSNs and an S/' approach" #n S-PH,

unlike these approaches, ser!ices are directly embedded on the WSN nodes and can be

in!oked from other nodes in the same network or other network connected to the former one"

#t is necessary to pro!ide efficient solutions that allow building 'm# en!ironments for

pro!iding dependent people healthcare at their homes" /ne of the key aspects for the

construction of these en!ironments is obtaining conte$t information through sensor networks"

There are se!eral healthcare de!elopments for telemonitoring based on WSNs" Howe!er,

these de!elopments do not take into account their integration with other systems and are

difficult to be adapted to new situations" The use of S-PH is proposed in order to face some

of the issues"



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare D

Chapter 3

Architecture

3.1 SY"!:

The following figure 7"1 illustrates the S-PH architecture layers"

%igure 3.1: SY!" architecture la$ers.

S-PH can be e$ecuted o!er multiple wireless de!ices independently of their

microcontroller or the programming language they use" S-PH works in a distributed way

so that the application code does not ha!e to reside almost completely on only central node"

S-PH allows the interconnection of se!eral networks from different wireless technologies,

such as AigBee or Bluetooth" Thus, a node designed o!er a specific technology can be

connected to a node from a different technology" #n this case, both WSNs are interconnected

by means of a set of intermediate gateways connected to se!eral wireless interfaces

simultaneously" S-PH allows applications to work in a distributed way and independent of

the lower layers related to the WSNs formation &i"e", network layer(, and the radio



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare G

transmission amongst the nodes that conform them &i"e", data link and physical layers("

S-PH implements an organi>ation based on a stack of layers" %ig" 7"1 shows the different

layers of S-PH, which are added o!er the application layer of each WSN stack" The

S-PH message layer &S;-( offers to the upper layers the possibility of sending

asynchronous messages between two wireless de!ices through the S-PH ser!ices protocol

&SSP("

The SSP is the internetworking protocol of the S-PH platform" SSP has

functionalities similar to those of the internet protocol P(" That is, it allows sending packets

of data from one node to another node regardless of the WSN to which each one belongs"

The messages specify the origin and target nodes, and the ser!ice in!ocation in a S-PH

ser!ices definition language &SS6-( format" The SS6- describes the ser!ice itself and its

parameters to be in!oked" 'pplications can directly communicate between de!ices, using the

S;- layer or by means of the S-PH ser!ices directory sub layer &SS6S( that uses in turn

the mentioned S;- layer" The SS6S offers functionalities related to the disco!ering of the

ser!ices offered by the network nodes" ' node that stores and maintains ser!ices tables is

called S-PH directory node &S6N("



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare C

The figure 7"2 below represents the S-PH basic operation"

%igure 3.2: SY!" basic operation.

The main components of S-PH are now described*

3.2 SY!" Services

The beha!ior of S-PH is in essence similar to the one of any other S/'" Howe!er,

S-PH has se!eral characteristics and functionalities that make it different from other

models" %ig" 7"2 shows the basic operation of S-PH" %irst, a ser!ice registers itself on the

S6N and informs its location in the network, the parameters it reuires and the type of

returned !alue after its e$ecution" #n order to do this, SS6- is used, which has been created

to work with limited resources nodes" SS6- is the interface definition language -( used

by S-PH" 6istributed architectures use an #6- in order to enable communication between

software components, regardless their programming language or hardware implementation"

Un. like other #6-s as WS6-, based on e$tensible markup language &:;-( and used on

web ser!ices" SS6- use a few intermediate separating tags and its ser!ices descriptions are

short binary data seuences" The reason for these constraints is to reduce processing in the

de!ices microcontrollers" Using a simple #6- allows, conseuently, utili>ing nodes with



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fewer resources, less power consumption, and lower cost" #n most cases, it is enough with a

few float point data for informing the status of a sensor" Thus, most ser!ice definitions

reuire only a few bytes" SS6- considers the basic types of data &e"g", integer, float, or

Boolean(, allowing more comple$ data structures as !ariable length arrays or character

strings" #n this way, SS6- is fle$ible enough to specify more comple$ ser!ices if reuired"

/nce the ser!ice has been registered in the S6N, it can be in!oked by any application by

means of S-PH" Both the S6N and the ser!ices can be stored in any node of the WSN or in

other subsystem connected to the WSN" This system can be, for instance, a simple personal

computer connected through a uni!ersal serial bus &USB( port to a wireless interface" Thus,

de!elopers decide, which nodes or subsystems will implement each part of the distributed

application" 'ny node in the network can ask the S6N for the location of a determined

ser!ice and its specification, using SS6-" This aspect is described in the following section"

The figure 7"7 below describes the S-PH 6irectory Nodes"

%igure 3.3: SY!" &irector$ 'odes.

3.3 SY!" &irector$ 'odes



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With the aim of the architecture to be the more distributed as possible, it is allowed to

be more than one S6N in the same network, so that can e$ist redundancy or ser!ices

organi>ed in different directories" The S6N can be stored in a node of the network, with a

memory e$ternal to the microcontroller if necessary, or be contained on a computationally

higher machine connected to the WSN, as is the case of a data ser!er or a personal computer

with wireless connection" %ig" 7"7 shows how a node can disco!er ser!ices in the network"

%or e$ample, node 1 registers itself in the WSN by means of S-PH" Then, it sends a

broadcast message after connecting to the WSN searching for e$isting S6Ns in the network"

't this moment, only the node is acti!e, therefore, after recei!ing the broadcast message, it

sends a message to the node 1 informing of its situation &i"e", SSP address( and its setup

parameters"

'n e$ample of a setup parameter is whether the S6N will inform periodically of its

presence or if the nodes will ha!e to poll it" 'fter this, the node 1 is able to communicate

with the node in order to obtain information about the possible ser!ices e$isting in the

network" -ater, the node 7 registers itself on the WSN" 's it has S6N functionalities, it

informs of this to the rest of the nodes by means of a broadcast message" The node 1 stores

this information on its SS6S entries list and informs node 7 about its role as S6N" 'ny node

in the network cannot only offer or in!oke S-PH ser!ices, but also includes S6N

functionalities in order to pro!ide ser!ices descriptions to other network nodes" S6Nsinclude additional information about ser!ices, whose locations in the network maintain as,

for e$ample, a uality of ser!ice rate and a time stamp that represents the last time the S6N

checked the ser!ice was a!ailable" 'n S6N can be configured to check the ser!ices, whose

location stores or can be the ser!ices the responsible for broadcast themsel!es periodically"

Chapter (



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)elemonitoring S$stem

This section describes the main features of a telemonitoring system aimed at impro!ing

healthcare of dependent people at their homes" The system makes use of se!eral WSNs in

order to gather conte$t information in an automatic and ubiuitous way" Thus, thetelemonitoring system enables an e$tensi!e integration of WSNs and pro!ides a greater

simplicity of deployment, thus optimi>ing the reutili>ation of the a!ailable resources in such

networks"

Se!eral functionalities are directly embedded on the WSN nodes and can be in!oked

from other nodes in the same network or other network connected to the former one by

means of the S-PH platform" S-PH gateways are used in order to interconnect different

heterogeneous WSNs" This way, S-PH contemplates the possibility of connecting WSNs

based on different radio and link technologies &e"g", AigBee, Bluetooth, Wi.%i, etc"(, while

other approaches do not" #n addition, S-PH focuses specially on de!ices with small

resources in order to sa!e microcontrollers) computing time, memory data si>e, and energy

consumption" Biomedical sensors &e"g", electrocardiogram, blood pressure, body temperature,

etc"( and automation sensors &e"g", building temperature, light, humidity, etc"( ha!e

significant differences, especially on how they collect data" Biomedical sensors obtain

continuous information about !ital signs, whose samples are important and should not be

lost" /n the other hand, automation sensors obtain information at a relati!ely lower

freuency compared to biomedical sensors" #n addition, biomedical sensors should be smaller

and easier to wear" #t is necessary to interconnect se!eral WSNs from different radio

technologies in a telemonitoring scenario" Ha!ing a compatible distributed platform for

deploying healthcare applications o!er the different networks facilitates the de!elopers) work

and the integration of the heterogeneous de!ices"

The figure @"1 illustrates basic schema of 4ommunication and infrastructure of the

telemonitoring system as shown below*



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%igure (.1: Communication and in#rastructure schema o# the telemonitoring s$stem

' network of AigBee de!ices has been designed to co!er the home of each patient to

be monitored" There is a AigBee remote control carried by the monitored patient that

incorporates a button, which can be pressed in case of remote assistance or urgent help"



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;oreo!er, there are a set of AigBee sensors that obtain information about the home

en!ironment &e"g", light, smoke, temperature, doors) states, etc"( in which the user li!es and

that physically response to the changes &e"g", light dimmers, fire alarms, or door locks(" 5ach

of these AigBee nodes includes a 4CE1%121 microcontroller and a 442@2 #555 C2"1E"@

radio freuency transcei!er" There are also se!eral Bluetooth biomedical sensors placed o!er

the monitored patient)s body" Biomedical sensors allow the system to acuire continuously

data about the !ital signs of the patient" #n the telemonitoring system presented in this paper,

each patient carries three different biomedical sensors* an 54F monitor, a respiration

monitor &implemented by means of an air pressure sensor(, and a micro.electro.mechanical

systems &;5;S( tria$ial accelerometer for detecting possible patient)s falls" These Bluetooth

nodes use a [email protected]$t chip with a reduced instruction set computer &=#S4(

microcontroller with @C ?B of ='; and 12@ ?B of e$ternal flash memory, and are

compatible with the Bluetooth 2" standard" 'll these AigBee and Bluetooth de!ices work as

S-PH nodes and can both offer and in!oke functionalities &i"e", ser!ices( throughout the

entire sensor network"

There is also a computer connected to a remote healthcare telemonitoring center !ia

#nternet" 'lerts can be forwarded from the patients) homes to the caregi!ers in the remote

center, allowing them to communicate with patients in order to check the possible incidences"These alerts can be, for instance, the detection of a patient)s fall or a high smoke le!el in the

patient)s home" This computer acts as a AigBee master node through a physical wireless

interface &e"g", a AigBee network adapter as a AigBee USB dongle, or a AigBee node

connected through the computer)s USB port(" The computer is also the master node of a

Bluetooth network formed by the biomedical sensors working as sla!e nodes" 't the S-PH

le!el, the computer performs as a S-PH gateway so that it connects both WSNs to each

other" #f, for instance, the monitored patient falls o!er the floor, his fall detector gets from its

Bluetooth accelerometer, a measurement higher than a pre!iously specified threshold" This

sensor &i"e", accelerometer( in!okes a ser!ice stored in the WSNs. #nternet S-PH gateway"

Such ser!ice initiates a !oice o!er #nternet Protocol &o#P( and webcam connection

to be established between the telemonitoring center and the patient)s home through #nternet"

This way, caregi!ers in the remote center can watch the patient)s home and talk with him in



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare 1@

order to !erify the accident" 's the telemonitoring center accesses directly to a patients

database, caregi!ers can see his medical data and home address" #f the accident is confirmed,

the caregi!ers send an ambulance to his home" 'lthough this system is mainly focused on

monitoring tasks, it also pro!ides additional useful facilities to the patients and caregi!ers"

%or e$ample, the remote center can consult really simple syndication &=SS( sources from

e$ternal and internal web ser!ers in order to obtain weather reports or entertainment options

for patients and inform them of their scheduled medical staff !isits" Such information is

shown on a graphical user interface &FU#( on a display connected to the computer at home"

This display is in fact a touch.sensiti!e screen, so that the interaction is easy and intuiti!e for

patients" ;oreo!er, the application includes home automation capabilities, so that a light

sensor can make a lamp to be switched on or dimmed by means of the in. !ocation, or a

certain ser!ice stored in a wireless actuator node connected to the relay or dimmer of the

respecti!e lamp"

Chapter *

+esults



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare 1E

The telemonitoring system presented in this report impro!es security at home to dependents"

#t implements monitoring and alerting subsystems, as well as additional ser!ices to

automatically react to emergency situations" We ha!e done se!eral test cases in order to

e!aluate the o!erall performance of the system, especially the management of emergency

situations" The tests, which in!ol!ed 17 patients and si$ caregi!ers, allowed us to e!aluate

the system" Specifically, the results of the S-PH system were studied o!er a period of four

weeks"

#t has been e!aluated that this approach in terms of the four main ob+ecti!es, defined

for WSN applied in healthcare de!elopments* minimi>e error rates, conduct diagnosis with

real time patient data, impro!e efficiency, and reduce costs" We ha!e collected data before

and after the implantation of the telemonitoring system, with data collected from %eb" 20

to ;ar" 20" The system was adopted on ;ar" 1, 20"

%igure *.1: %alse positives occurred during the test period o# the alert subs$stem

%irstly, our approach pro!ides the system with a higher ability to reco!er from errors"

%ig" E"1 shows the percentage of error that occurred in the alert subsystem during the tests"

The initial tests showed an error rate abo!e 10I" This percentage was primarily due to errors

in the use of the system by the caregi!ers" 'fter the third test, the error rate was reduced to



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare 1D

11I" %rom this point the error rate remained stable at @I" This error could be reduced with a

higher le!el of training in the use of the telemonitoring system" Secondly, we ha!e worked

with real.time data from the patients"

These data ha!e not been used for diagnosis, but to assess the need for pro!iding

healthcare to the patients" #n this sense, S-PH reaches this goal because it can work with

real.time data" Howe!er, it is necessary to include a reasoning mechanism in order to

facilitate the decision making for diagnosis" %inally, the efficiency of the telemonitoring

system has been enhanced and the infrastructure costs ha!e been reduced" S-PH allowed us

to determine the time needed to respond to alerts generated by the users or the sensors" #n

order to generali>e reactions to common situations, the system does not only take response

time into account, but also the time elapsed between alerts and the user)s profile and

reliability"

The telemonitoring system allows a reduction of the response time to incidents &i"e",

alerts(" When comparing data before and after the implantation of the telemonitoring system,

we concluded that telemonitoring system pro!ides an a!erage response time to incidents of C

min, which reduces the time employed by the caregi!ers in a GI" ;oreo!er, the a!erage of

assisted incidents per day was 12, pro!iding a reduction of 11I" This reduction can be

directly associated to the impro!ement in the detection of false positi!es" Besides, the time

employed by the medical staff to attend an alert has been notably reduced"

Chapter ,

Conclusion



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare 1G

S-PH allows wireless sensor de!ices from different radio technologies to work together in

a distributed way" These sensor de!ices do not ha!e to be pro!ided with large memory chips

or fast microprocessors" The S-PH model allows the possibility of adding or remo!ing

components at e$ecution time" This way, it is possible to add a new automation sensor in the

patient)s home at e$ecution time with no need of reprogram or redeploy the system" #f, for

e$ample, it is decided to add a new smoke sensor in the patient)s home, the technician will

+ust ha!e to fi$ it to the ceiling and supplies it with electrical power" The AigBee node will

+oin automatically to the AigBee automation network, and its S-PH layers will look for

S6Ns and ser!ices in the S-PH network and register its own ser!ices on them" This way, if

the new smoke sensor detects a dangerous smoke le!el, it will automatically in!oke the

smoke alarm ser!ice in the alarm nodes in the home and the WSNs #nternet S-PH gateway"

The telemonitoring system)s architecture goes a step ahead in designing systems for

home care by offering features that make it easily adaptable to any per!asi!e en!ironment"

Unlike other telemonitoring systems as, the presented system allows to integrate

heterogeneous sensor networks from different technologies, e!en wired ones" Therefore, it is

possible to +oin automation and biomedical sensors in the same telemonitoring system, using

the technology that better fits each sensor)s data characteristics"

'lthough the initial results are promising, the telemonitoring systems still reuires

some impro!ements" /ur future work focuses on finding a modeling facility to pro!idelearning and decision.making capabilities to the system"

+e#erences



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Using Heterogeneous Wireless Sensor Networks in a Telemonitoring System for Healthcare 1C

J1K F" T" heimer patients, agent technology for healthcare,M Decis. Support Syst., !ol"

@@, pp" 7C2370D, 2C"

J7K W" H" /rgani>ation, Global Age-Friendly Cities" Fene!a, Swit>erland* World Health

/rgani>ation, 2G"

J@K =" N" 'nderson, L' method for constructing complete annual U"S" life tables,M ital

Health Statist. Ser., !ol" 120, pp" 132C, 2"

JEK ;" Fast and ;" S" Fast, !"#.$$ %ireless &et'or(s) *he De+initive Guide" Sebastopol,

4'* /)=eilly, 22"

JDK -" 4amarinha.;atos and H" 'fsarmanesh, L' comprehensi!e modeling framework for

collaborati!e networked organi>ations,M ,. ntell. anu+., !ol" 1C, pp" E203E@2, /ct" 2G"

JGK 4" Singh, '" ?umar, and P" 'meer, LPerformance e!aluation of an #555 C2"1E"@ sensor

network with a star topology,M %ireless &et'., !ol" 1@, pp" E@73EDC, 2C"

JCK P" Baronti, P" Pillai, " W" 4" 4hook, S" 4hessa, '" Fotta, and " %" Hu, LWireless sensor

networks*'sur!ey on the state of the art and the C2"1E"@ and AigBee standards,M Co/put.

Co//un., !ol" 7, pp" 1DEE31D0E, 2G"

J0K ;" #lyas, *he Handboo( o+ Ad hoc %ireless &et'or(s" Boca =aton, %-* 4=4 Press, 22"

J1K 5" Song and ?" -ee, LSTWS* ' unified web ser!ice for #555 1@E1 smart transducers,M

000 *rans. nstru/. eas., !ol" EG, no" C, pp" 1G@031GED, 'ug" 2C"



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J11K -" %ass, LPatient.centric healthcare,M in Proc. 1rd nst. 0ng. *echnol. nt. Con+. ed.

0lectr. Devices *echnol. 20D*0CH #""34, pp" GG310"

J12K '" 6"

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