dcs final ppts

8/7/2019 Dcs Final Ppts

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The distance over which data moves within a

computer may vary from a few thousandths of

an inch, as is the case within a single IC chip,

to as much as several feet along the backplaneof the main circuit board. Over such small

distances, digital data may be transmitted as

direct, two-level electrical signals over simple

copper conductors. Except for the fastest

computers, circuit designers are not very

concerned about the shape of the conductor or the analog characteristics of signal

transmission.



�To allow computers with different disk

OS, languages, and cabling to share

resources.

�I would define data communication asthe transfer of information between two

points, either via an analogue (sine wave)

electrical signal. or digital (binary ) signal

via electrical pulses or optically via light

pulses�Data communication is transmission of

digital data through communication

systems . This has the objective of

sending any documents or books at

highest speeds and lowest cost.



Before the advent of computer networks that were based upon some type of telecommunications system, communication

between calculation machines and early computers was performed by human users by carrying instructions between them.

Many of the social behaviors seen in today's Internet were demonstrably present in the nineteenth century and arguably in

even earlier networks using visual signals.

�In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model at

Dartmouth College to his Complex Number Calculator in New York and received results back by the same means.

Linking output systems like teletypes to computers was an interest at the Advanced Research Projects Agency (ARPA)

when, in 1962, J.C.R. Licklider was hired and developed a working group he called the "Intergalactic Network", a

precursor to the ARPANET.

�In 1964, researchers at Dartmouth developed the Dartmouth Time Sharing System for distributed users of large computer

systems. The same year, at Massachusetts Institute of Technology, a research group supported by General Electric and

Bell Labs used a computer to route and manage telephone connections.

�Throughout the 1960s Leonard Kleinrock , Paul Baran and Donald Davies independently conceptualized and developed

network systems which used packets that could be used in a network between computer systems.

�1965 Thomas Merrill and Lawrence G. Roberts created the first wide area network (WAN).

�The first widely used telephone switch that used true computer control was introduced by Western Electric in 1965.

�In 1969 the University of California at Los Angeles, the Stanford Research Institute, University of California at Santa

Barbara, and the University of Utah were connected as the beginning of the ARPANET network using 50 kbit/s circuits.

�Commercial services using X.25 were deployed in 1972, and later used as an underlying infrastructure for expanding

TCP/IP networks.



Data Flow Diagram Symbols:

There are some symbols that are used in the drawing of business process diagrams (data flow diagrams). These

are now explained, together with the rules that apply to

them.

Flow diagrams in general are usually designed using

simple symbols such as a rectangle, an oval or a circle

depicting a processes, data stored or an external entity,

and arrows are generally used to depict the data flow

from one step to another.

ADFD usually comprises of four components. These

four components can be represented by four simple

symbols. These symbols can be explained in detail as

follows: External entities (source/destination of data) are

represented by squares; Processes (input-processing-

output) are represented by rectangles with rounded

corners; Data Flows (physical or electronic data) are

represented by arrows; and finally, Data Stores (physical

or electronic like XML files) are represented by open-

ended rectangles.



Data flow diagrams present the logical

flow of information through a system in

graphical or pictorial form. Data flow

diagrams have only four symbols, which

makes useful for communication between

analysts and users. Data flow diagrams

(DFDs) show the data used and provided

by processes within a system. DFDs make

use of four basic symbols.Create structured analysis, information

flow, process-oriented, data-oriented, and

data process diagrams as well as data

flowcharts.



A communications channel is a pathway over which information can

be conveyed. It may be defined by a physical wire that connectscommunicating devices, or by a radio, laser, or other radiated energy

source that has no obvious physical presence. Information sent

through a communications channel has a source from which the

information originates, and a destination to which the information is

delivered. Although information originates from a single source, there

may be more than one destination, depending upon how many receivestations are linked to the channel and how much energy the

transmitted signal possesses.

In a digital communications channel, the information is represented

by individual data bits, which may be encapsulated into multibit

message units. A byte, which consists of eight bits, is an example of amessage unit that may be conveyed through a digital communications

channel. A collection of bytes may itself be grouped into a frame or

other higher-level message unit. Such multiple levels of encapsulation

facilitate the handling of messages in a complex data communications

network



INTERNET:

The Internet is a global system of interconnected

computer networks that use the standard Internet Protocol

Suite (TCP/IP) to serve billions of users worldwide. It is a

network of networks that consists of millions of private,

public, academic, business, and government networks, of

local to global scope, that are linked by a broad array of

electronic, wireless and optical networking technologies.

The Internet carries a vast range of information resourcesand services, such as the inter-linked hypertext documents

of the World Wide Web (WWW) and the infrastructure to

support electronic mail.

Most traditional communications media including

telephone, music, film, and television are reshaped or

redefined by the Internet, giving birth to new services such

as Voice over Internet Protocol (VoIP) and IPTV.

Newspaper, book and other print publishing are adaptingto Web site technology, or are reshaped into blogging and

web feeds. The Internet has enabled or accelerated new

forms of human interactions through instant messaging,

Internet forums, and social networking. Online shopping

has boomed both for major retail outlets and small artisans

and traders. Business-to-business and financial services on

the Internet affect supply chains across entire industries



WIRELESSIn telecommunications, wireless communication may

be used to transfer information over short distances (a

few meters as in television remote control) or long

distances (thousands or millions of kilometers for radio

communications). The term is often shortened to

"wireless". It encompasses various types of fixed,

mobile, and portable two-way radios, cellular

telephones, personal digital assistants (PDAs), and

wireless networking. Other examples of wireless

technology include GPS units, garage door openers and

or garage doors, wireless computer mice, keyboards

and headsets, satellite television and cordless

telephones



The interactive Communication And Distance Education (CADE) system operates in a live satellite, teleconferencing, or

streaming video broadcast environment. CADE facilitates one-way video, two-way audio and data communication. It can be

used for such diverse interactive applications as:

y Distance Learning & Training

y Corporate Communication

y New product/process introduction

y Internal marketing surveys with immediate results

Meetings that don¶t require expensive and time-consuming travel

Improving the ³touch´ with remote locationsVendor sponsored presentationsInviting customers to local sites for special presentationsExtracting hidden "knowledge assets" andFacilitating knowledge transferCADE provides live data, text, web, and audio interaction between the Instructor and or Presenterand the remote participants located throughout the country or the world.Audio - Participant's can speak over an internet connectionData - Collect answers to multiple-choice, true/false, yes/no, numeric questionsRecorded Audio - Record audio questions for topic expertsText - Live chat between Presenter and a site or groups of sitesVideo - View streaming video in lieu of satellite broadcastWeb Pages - Synchronized delivery of web pages to learnersThe CADE system also supports off-Line applications. Not everything happens during a livebroadcast so the CADE



Yes, there are vast differences. But the biggest difference by far

is that there is less face-to-face communication. It's either

(cell)phone, E-mail or Festoon. No matter which alternative,

face-to-face communication has an extra dimension: facial

expression.

When I am on the phone I like to imagine what the other party

really thinks. I can listen to his tone of voice, try to understand

the pauses and try to figure out what he/she is really saying.

That is why counseling over the internet is only second best

In the past there was communication devices that we now do

not have. In the past there were such things as smoke signals,

telegraphs, carrier pigeons, animal sounds and early

telephones. plus letters. In the present we have cell phones,

telephones, email addresses, fax machines, and more. so that's

the differences of the communication system in the past and

today the presents of the 21st centuries.Today the internet is more high powered and is used alot for

doing research and finding information.In the past the internet

wasn't able to do alot of these things



Near Field Communication (NFC) does seem to be one of the more interesting trends for this year,

where it will see action on the mobile platform soon as well. NFC is also making its way into the US

and Europe markets via a range of channels, and you can add BMW to the list of supporters with its

NFC key of the future. BMW researchers are hoping to link the vehicle¶s key to its navigation and

entertainment system, letting you for example, reserve a hotel room for your anniversary or

purchase coach tickets right from the comfort of your ultimate driving machine. Currently however,all of this remains in the R&D phase and will most likely see implementation in the next generation of

ConnectedDrive if all goes well.

³Welcome to the worlds most influential media forum´, said HSH Prince Albert II of Monaco at the

beginning of the Monaco Media Forum 2010. Indeed the event is not only inspirational, but is also

bringing together the a very influential group of people in the media business. During the almost

three days, I met founders, entrepreneurs, investors but also executives of the big media

companies. Here are some key trends reflected in my video interviews«.



Current trends in technical communications

The rise of embedded user assistance

Many technical writers are developing usability skills and

leveraging them to help improve the product interface. Help

is being delivered within the interface itself. Drop-down lists

of topics related to an interface component, hint text below

a GUI field, and other such embedded user assistance

models allow users to get help without leaving the

application interface.Traditional help lives as a separate application, and

requires users to learn to navigate the help interface.

However, embedded help is less removed from the product

and is less disruptive to the overall workflow.

Currently there are few embedded user assistance tools

available, but I believe this will be a promising area of

growth for tool developers in the near future.

Developer cooperation is also a potential stumbling block

since most writers have no control over the productinterface. Technical communicators need to build positive

relationships with developers and show them the benefits

of implementing embedded help.

Increased reliance on multimedia



T he Future of Wireless Data Communication:

The wireless data communication (WDC) services are penetrating the market increasingly faster in

recent years. The two main alternative WDC technologies are the wireless LAN and the mobile Internetservice. There is our previous research[1] about the services. These services show many differences in

their quality attributes, such as the device, quality of communication, data transmission speed, pricing

system and so on. Consumers¶ choice between these two alternatives will be determined by their

preferences over different quality attributes and in turn, will have a powerful impact on the evolution of

WDC services and related technologies in the future.

In this study, we analyze consumers¶ valuation of quality attributes in the wireless LAN and mobile

Internet services. Consumer choice is crucial to the success in the WDC-related businesses since the

WDC market is growing very fast and competition among the WDC service providers will become quite

intensive. Methodologically we employ conjoint analysis, which makes the respondents rate hypotheticalservice alternatives featuring various combinations of quality attributes. By estimating consumers¶

willingness to pay for the attributes of the WDC services based upon surveyed stated preference data

from the conjoint experiment, we predict the evolution of the WDC services and related technologies

along various quality dimensions compared with the result of previous research[1] using redesigned

questionnaire. Based on the estimation results, we draw policy implications for the national- and

company-level R&D strategy.



Data Communication Applications

Agenda

Application CategoryEvolutionApplicationsInternet, Intranet, & ExtranetConsiderationsApplication Category

Human-machine interactionPerson-to-personPerson-to-machine or machine-to-personMachine-to-machine

Type of informationVoice or dataStructured or unstructuredStatic image or dynamic image

TimelinessOn-lineReal-time

Store-and forwardBatch



EvolutionTelegraphAdministrative message switchingComputers

TelegraphMorse CodeDots and dashesSlow

No error correctionMessage Switching SystemsEquipment: teletypewriters

Types: torn tape message systemPoint-to-pointMultipoint lineCollision, polling, address, and protocolControl or master station and subordinate or slave

stationComputers

BenefitsInquiryFile updating

TimesharingOther applications (TPS, MIS, DSS, EX, EC)

TypesCentralizedDistributedClient-server



Applications - IAirline reservation system

American airline: Sabre systemUnited airline: Apollo reservationsystem

Automatic teller machineSwift: Society for WorldwideInterbank FinancialTelecommunication

Sales order entryPoint of saleUniversal product code

Applications - IIUnstructured data application

Electronic mail

Ownership of contentSimple mail transfer protocol(SMTP)

No foreign charactersNo executable filesLimited size

Multipurpose Internet mailextensions MIME



Applications - IIIImage application

Facsimile (FAX)

Simple for printed documentationTelevision

Purpose

SecurityInformationConference

Types

Freeze-frame & full-motion

One-way & two-wayInternet, Intranet, ExtranetInternet

Browser program

Netscape¶s NavigatorMicrosoft¶s Internet ExplorerUniform Resource Locator (URL)

World Wide Web (WWW)Hypertext transfer protocol (http)Internet service provider (ISP): tier 1, tier 2, tier 3

Intranet

ExtranetConsideration

Response timeUser expectation

consistency

SecurityPlanning for failures

Do nothing

Manual systemBack up computer & linesHot standby system

Disaster Recovery

Mutual aid pactCommercial service: Comdisco Disaster Recovery Services

Planning & testing regularly



Pros of Electronic Communication

The benefits of electronic communication is that people across the world can share televised pictures, conversations,

graphics, circuits and interactive softwares. The interaction between people residing in different geographical locations

have increased and have become promiscuous. The conversations are more visual and textual. This is helpful mainly for

hearing impaired people. With electronic communication, the recipient receives the message within a few seconds of the

sender sending it. The recipient can read the message anytime, anywhere according to his convenience.

The speed of conversation has increased and this has resulted in faster processing of important matters related to

business, finance, trade, etc. For example, you can instantly access the information present in your computer. As there

are no restrictions about time and place, people can sit at home and do their of fice work if the required resources are

available.This work arrangement is termed as telecommuting. The communicated messages can be stored permanently

or temporarily on disks or tapes for years or can even be printed and stored in files. The process of learning has become

simple and efficient as the information can be archived and retrieved according to the requirement. Since the

communication does not take place via hard copies, money spent for paper, printing and postal deliveries is saved. After

the mail is delivered to the receiver, it is placed safely in the hard disk of the receiver's computer. After the receiver

retrieves the mail, it is his responsibility to keep it safely



Cons of Electronic Communication

The main issue with electronic communication is security. Your computer can be

hacked and affected with computer virus. This can have an adverse effect on

the computer system and the network. The volume of transmitted data is large

and the transmission is fast. Hence, it becomes difficult for employers and

managers to absorb, process and understand it and provide proper feedbacks

to their employees. The speed with which the messages are transmitted often

changes the structure of the messages, which at times can be misinterpreted.

Electronic data can be duplicated identically without any proof of duplication.

These messages can also be modified. At times, people can intentionally send

malicious programs like viruses, worms and Trojans through emails, which is

difficult to detect.

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