topic 1 - introduction to information systems engineering

7/23/2019 Topic 1 - Introduction to Information Systems Engineering

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IN TRO D U CTIO N

ITS572 - InformationSystems Engineering



Topics covered

Professional software development –software engineering

Software engineering ethics



Softw are Products

Generic

Stand-alone systemsthat are mareted andsold to any c!stomerwho wishes to "!ythem

The speci#cation ofwhat the softwaresho!ld do is owned "ythe software developerand decisions onsoftware change aremade "y the developer

$espoe%&!stomi'ed

Software that iscommissioned "y aspeci#c c!stomer tomeet their own needs

The speci#cation ofwhat the softwaresho!ld do is owned "ythe c!stomer for thesoftware and theymae decisions onsoftware changes thatare re(!ired



Essential Attributes of G ood Softw are

Product characteristic Description

Maintainability Software should be written in such a way so that it can evolve to meetthe changing needs of customers. This is a critical attribute becausesoftware change is an inevitable requirement of a changing businessenvironment.

Dependability and security Software dependability includes a range of characteristics includingreliability, security and safety. Dependable software should not causephysical or economic damage in the event of system failure. Malicioususers should not be able to access or damage the system.

Efficiency Software should not mae wasteful use of system resources such asmemory and processor cycles. Efficiency therefore includes

responsiveness, processing time, memory utilisation, etc.

!cceptability Software must be acceptable to the type of users for which it isdesigned. This means that it must be understandable, usable andcompatible with other systems that they use.



Softw are Engineering

SoftwareEngineeri

ng

)ethods

Tools Theorie

s

An engineeringdiscipline thatis concerned

with all aspects

of softwareproduction

Concern ed withcost-eective

softwaredevelopment



Softw are Engineering D iversit

There are many di*erent types ofsoftware system and there is no!niversal set of software techni(!es

that is applica"le to all of these+

The software engineering methods andtools !sed depend on the type of

application "eing developed, there(!irements of the c!stomer and the"acgro!nd of the development team+



Fitting into Inform ation System s

system is a gro!p of interrelated componentsthat f!nction together to achieve a desiredres!lt+

n information system .IS/ is an arrangementof people, data, processes, and informationtechnology that interact to collect, process,store, and provide as o!tp!t the information

needed to s!pport an organi'ation+

Information technology is a contemporaryterm that descri"es the com"ination of comp!tertechnology .hardware and software/ with

telecomm!nications technology .data, image,



Types of Inform ation System s

transaction processing system .TPS/ is aninformation system that capt!res and processesdata a"o!t "!siness transactions+

management information system .)IS/ isan information system that provides formanagement-oriented reporting "ased ontransaction processing and operations of theorgani'ation+

decision support system .0SS/ is aninformation system that either helps to identifydecision maing opport!nities or providesinformation to help mae decisions+



Types of Inform ation System s (cont.)

n expert system is an information systemthat capt!res the e1pertise of worers and thensim!lates that e1pertise to the "ene#t of non-e1perts+

communications and collaborationsystem is an information system that ena"lesmore e*ective comm!nications "etween

worers, partners, c!stomers, and s!ppliers toenhance their a"ility to colla"orate+

n oce automation system is an

information system that s!pports the widerange of "!siness oce activities that provide



A!!lication T!es

Stand-alone applications

These are application systems that r!n on alocal comp!ter, s!ch as a P&+ They incl!de all

necessary f!nctionality and do not need to "econnected to a networ+

Interactive transaction-"ased applications

pplications that e1ec!te on a remote comp!terand are accessed "y !sers from their own P&s or

terminals+ These incl!de we" applications s!chas e-commerce applications+

Em"edded control systems

These are software control systems that control

and manage hardware devices+ 4!merically,there are ro"a"l more em"edded s stems



A!!lication T!es "cont#$

$atch processing systems

These are "!siness systems that are designed toprocess data in large "atches+ They processlarge n!m"ers of individ!al inp!ts to createcorresponding o!tp!ts+

Entertainment systems

These are systems that are primarily forpersonal !se and which are intended to

entertain the !ser+ Systems for modeling and sim!lation

These are systems that are developed "yscientists and engineers to model physical

processes or sit!ations, which incl!de many,se arate, interactin o" ects+



A!!lication T!es "cont#$

0ata collection systems

These are systems that collect data from theirenvironment !sing a set of sensors and sendthat data to other systems for processing+

Systems of systems

These are systems that are composed of an!m"er of other software systems+



Softw are Process Activities

Software specication, where c!stomersand engineers de#ne the software that is to "eprod!ced and the constraints on its operation+

Software development, where the softwareis designed and programmed+

Software validation, where the software ischeced to ens!re that it is what the c!stomer

re(!ires+ Software evolution, where the software is

modi#ed to re3ect changing c!stomer andmaret re(!irements+



G eneral Issues t%at Affect & ostSoftw are

6eterogeneity

Increasingly, systems are re(!ired to operate asdistri"!ted systems across networs that incl!dedi*erent types of comp!ter and mo"ile devices+

$!siness and social change

$!siness and society are changing incredi"ly (!iclyas emerging economies develop and newtechnologies "ecome availa"le+ They need to "ea"le to change their e1isting software and to rapidlydevelop new software+

Sec!rity and tr!st

s software is intertwined with all aspects of o!rlives, it is essential that we can tr!st that software+



Softw are Engineering and t%e w eb

The e" is now a platform for r!nningapplication and organi'ations are increasinglydeveloping we"-"ased systems rather than

local systems+ eb services allow application f!nctionality

to "e accessed over the we"+

Cloud computing is an approach to the

provision of comp!ter services whereapplications r!n remotely on the 8clo!d9+

:sers do not "!y software "!t pay accordingto !se+



' eb Softw are Engineering

" Software re!se is the dominant approach forconstr!cting we"-"ased systems+

# hen "!ilding these systems, yo! thin a"o!thow yo! can assem"le them from pre-e1istingsoftware components and systems+

" e"-"ased systems sho!ld "e developed anddelivered incrementally+

# It is now generally recogni'ed that it is

impractical to specify all the re(!irements fors!ch systems in advance+

" :ser interfaces are constrained "y the capa"ilitiesof we" "rowsers+

# Technologies s!ch as ;< allow rich interfaces to"e created within a we" "rowser "!t are still$TS%&' (ectture ) * +SM '-)'

i i



' eb Softw are Engineering "cont#$

" e"-"ased systems are comple1 distri"!tedsystems "!t the f!ndamental principles of softwareengineering disc!ssed previo!sly are as applica"leto them as they are to any other types of system+

" The f!ndamental ideas of software engineering,disc!ssed in the previo!s section, apply to we"-"ased software in the same way that they apply toother types of software system+

i i i



Softw are Engineering Et%ics

" Software engineering involves widerresponsi"ilities than simply the application oftechnical sills+

" Software engineers m!st "ehave in an honestand ethically responsi"le way if they are to "erespected as professionals+

" Ethical "ehavio!r is more than simply

!pholding the law "!t involves following a setof principles that are morally correct+

$TS%&' (ectture ) * +SM '-)'

i i ii



Issues of Professional Res!onsibilit

" &on#dentiality # Engineers sho!ld normally respect the

con#dentiality of their employers or clientsirrespective of whether or not a formalcon#dentiality agreement has "een signed+

" &ompetence # Engineers sho!ld not misrepresent their

level of competence+ They sho!ld not

nowingly accept wor which is o!t withtheir competence+

f f i l ibili



Issues of Professional Res!onsibilit

" Intellect!al property rights # Engineers sho!ld "e aware of local laws governing

the !se of intellect!al property s!ch as patents,copyright, etc+ They sho!ld "e caref!l to ens!re that

the intellect!al property of employers and clients isprotected+

" &omp!ter mis!se # Software engineers sho!ld not !se their technical

sills to mis!se other people9s comp!ters+ &omp!termis!se ranges from relatively trivial .game playingon an employer9s machine, say/ to e1tremely serio!s.dissemination of vir!ses/+

AC& (IEEE C d fE %i



AC& (IEEE Code of Et%ics

" The professional societies in the :S havecooperated to prod!ce a code of ethical

practice+" )em"ers of these organisations sign !p to thecode of practice when they oin+

" The &ode contains eight Principles related tothe "ehavio!r and decisions made "y

professional software engineers, incl!dingpractitioners, ed!cators, managers,s!pervisors and policy maers, as well astrainees and st!dents of the profession+

AC& (IEEE C d fEt%i



AC& (IEEE Code of Et%ics

Software !ngineering Code of !thics and "rofessional "ractice

&)%IEEE-&S ;oint Tas =orce on Software Engineering Ethics and ProfessionalPractices "#!A$%&!

The short version of the code s!mmari'es aspirations at a high level of thea"straction> the cla!ses that are incl!ded in the f!ll version give e1amples anddetails of how these aspirations change the way we act as software engineeringprofessionals+ itho!t the aspirations, the details can "ecome legalistic andtedio!s> witho!t the details, the aspirations can "ecome high so!nding "!tempty> together, the aspirations and the details form a cohesive code+

Software engineers shall commit themselves to maing the analysis,speci#cation, design, development, testing and maintenance of software a"ene#cial and respected profession+ In accordance with their commitment to thehealth, safety and welfare of the p!"lic, software engineers shall adhere to thefollowing Eight Principles?

Et%i lP i i l



Et%ical Princi!les

$TS%&' (ectture ) * +SM '-)'

A+ P:$BI& - Software engineers shall act consistently with the p!"lic interest+

2+ &BIE4T 40 E)PBCDE - Software engineers shall act in a manner that is inthe "est interests of their client and employer consistent with the p!"lic interest+

F+ PC0:&T - Software engineers shall ens!re that their prod!cts and relatedmodi#cations meet the highest professional standards possi"le+

+ ;:0G)E4T - Software engineers shall maintain integrity and independence intheir professional !dgment+

5+ )4GE)E4T - Software engineering managers and leaders shall s!"scri"e toand promote an ethical approach to the management of software developmentand maintenance+

H+ PC=ESSIC4 - Software engineers shall advance the integrity and rep!tationof the profession consistent with the p!"lic interest+

7+ &CBBEG:ES - Software engineers shall "e fair to and s!pportive of theircolleag!es+

+ SEB= - Software engineers shall participate in lifelong learning regarding thepractice of their profession and shall promote an ethical approach to the practice

of the profession+

R ti l f t% C d fEt%i



Rationale for t%e Code of Et%ics

Computers have a central and growing role in commerce,industry, government, medicine, education, entertainmentand society at large. Software engineers are those whocontribute by direct participation or by teaching, to theanalysis, specication, design, development, certication,

maintenance and testing of software systems.

Because of their roles in developing software systems,software engineers have signicant opportunities to do good

or cause harm, to enable others to do good or cause harm,or to inuence others to do good or cause harm. To ensure,

as much as possible, that their eorts will be used for good,software engineers must commit themselves to maingsoftware engineering a benecial and respected profession.

Et%i lD il



Et%ical D ile) ) as

0isagreement in principle with the policies of seniormanagement+

Do!r employer acts in an !nethical way and releases asafety-critical system witho!t #nishing the testing ofthe system+

Participation in the development of military weaponssystems or n!clear systems+

*A+ b tS ft E i i



*A+ about Softw are Engineering

uestion !nswer

/hat is software0 1omputer programs and associated documentation.Software products may be developed for a particularcustomer or may be developed for a general maret.

/hat are the attributes of good software0 2ood software should deliver the required functionalityand performance to the user and should bemaintainable, dependable and usable.

/hat is software engineering0 Software engineering is an engineering discipline that isconcerned with all aspects of software production.

/hat are the fundamental softwareengineering activities0

Software specification, software development, softwarevalidation and software evolution.

/hat is the difference between software

engineering and computer science0

1omputer science focuses on theory and fundamentals3

software engineering is concerned with the practicalitiesof developing and delivering useful software.

/hat is the difference between softwareengineering and system engineering0

System engineering is concerned with all aspects ofcomputer*based systems development includinghardware, software and process engineering. Softwareengineering is part of this more general process.

*A+ b tS ft E i i



*A+ about Softw are Engineering

Question Answer

/hat are the ey challenges facingsoftware engineering0

1oping with increasing diversity, demands for reduceddelivery times and developing trustworthy software.

/hat are the costs of softwareengineering0

4oughly 5-6 of software costs are development costs,7-6 are testing costs. 8or custom software, evolutioncosts often e9ceed development costs.

/hat are the best software engineeringtechniques and methods0 /hile all software pro:ects have to be professionallymanaged and developed, different techniques areappropriate for different types of system. 8or e9ample,games should always be developed using a series ofprototypes whereas safety critical control systems requirea complete and analy;able specification to be developed.ou can<t, therefore, say that one method is better thananother.

/hat differences has the web made tosoftware engineering0

The web has led to the availability of software servicesand the possibility of developing highly distributed service*based systems. /eb*based systems development hasled to important advances in programming languages andsoftware reuse.



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topic 1 - introduction to information systems engineering

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