ict117 week01fundamantal concepts s

8/6/2019 ICT117 Week01Fundamantal Concepts s

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ICT117 Systems Analysisand DesignSemester 1, 2011

Important information from the UnitOutline

Andrew Barnden 9286 [email protected]


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1. 2ICT117 Systems Analysis & Design, Sem 2, 201017 March 2011

Systems theorySystem development overviewModelling techniques UML V2.0Requirements gathering for modellingInterpreting the modelsDocumenting the system

Topics studied


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Appreciation of business processesAppreciation of complexityUsing abstraction to manage complexityUnderstand the systems development process androlesBecome proficient in modelling techniquesBecome proficient in information gatheringUnderstand the importance of documentation(communication)

leading to LearningOutcomes


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2 assignments 40% (15% + 25%)Text book exercises 10%2.5 hour closed book exam 50%You must achieve a minimum of 50% in theexam to pass the unitRe-sit eligibility is a minimum 45% overall plusa minimum of 40% on examYou require a copy of the text book in order tocomplete the set exercises

Administrative details


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Knowing the overhead slide material alone isnot sufficient to passReading and understanding the text book is

required prior to the associated lectureAttendance at lectures and tutorials isrequired

Necessary and sufficient


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You must know how to efficiently find reliableinformation, and know how to cite it.Three tutorials will develop those abilitiesAcademic misconduct must not occur in anyassessable work

see StudentWeb>Comm itments andPolicies>Conduct Management>Plagiarism,Collusion & Cheating Policy & Procedure

Information literacy


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Both assignment submissions must conform tothe specification stated in each assignmentThe second assignment requires Information

System models created in UML V2.0 usingdiagramming softwareTutorial exercises in modelling also must usediagramming softwareMicrosoft Visio is licensed for use at BHIAll assignments must include the Cover Sheet

Submitting work


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ICT117 SYSTEMS ANALYSISAND DESIGNWeek 1: Concepts of System, Information and Abstraction


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Understand the dichotomy between Realityand ConceptUnderstand the concept of SystemUnderstand abstractionUnderstand Data, Information, KnowledgeUnderstand Information Systems

Lecture objectives


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1.10ICT117 Systems Analysis & Design, Sem 2, 201017 March 2011

Real:tangible, concrete, existing, objective,visible

Conceptual:intangible, idea, thought, planned, belief

Conceptual things are in our mind and realthings exist in our worldIT professionals regularly work withconceptual things

Reality cf. Concept


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What is a system?A working real thing.An inter-connectedwhole.A consistent way ofdoing something.An organised way ofthinking aboutsomething.A framework for makingsense of something.


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a purposive unitary wholecomposed of interrelated partshierarchically organisedshows emergent propertiescapable of communication with itsenvironmentable to change its operations in response toenvironmental stimuli (communications)

The concept of System


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An identifiable set of interacting components,hierarchically constructed, operating as anintegrated whole with emergent propertiesand reacting to its environment in order toachieve some purposeful outcome.

System definition


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A whole thing; has a boundary; accepts inputfrom its environment; produces output;purposive (intended to achieve a purpose);composed of interacting sub-systems(components); exhibits emergent behaviour

Emergence: behaviour that is only possiblethrough the operation of the whole system

System characteristics


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Designed to implement business policiesPerformed regularlyPerformed consistentlySpecific to their inputsConsistent in their outputs

e.g. the way Ford makes doors for Falconcarse.g. the way BHI assesses ICT117 students

Systematic processes


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DATA, INFORMATION,KNOWLEDGE


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51092ATM01000111010001111001010000000000- what are these?Measurement, context, understandingMeaning the understanding that we interpretfrom the information available

Data, Information,Knowledge


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Measurements of real world attributes thatrequire context, units of measure,intentions for us to make sense of asituationInformation is data in context that enables usto make decisions

Knowledge is the understanding that ourinformed decision is correct in the currentcircumstances

Data (plural) Datum (sing.)


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PRACTICAL USES OF THESECONCEPTS


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Businesses and organisations makepurposeful decisions in their day to dayoperations based on informationBusiness purposes are achieved by variousprocessesThere may be many purposes, but usually oneover-riding purpose: that of business

continuity, success and prosperity

Business data andprocesses


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To sell a product?To provide a service?To buy materials?To pay staff?To install a PC network?

Divide the task and conquer it

What information is needed?


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representing something in a simpler formremoving non-essential detailsbut retaining the essence of the originalA model is:

Smaller scale

Simpler

Accurately representative

Cheaper to construct

abstraction


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Abstraction

Booch et al (2007) pg 45


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Network diagramabstraction of cables, routers, bridges,switches, access points, characteristics intosymbolsTonka truckan abstraction of the form, and some functionsinto an artefact

Text description e.g. cake recipeabstraction of components and process stepsinto English sentences

Different forms of abstraction


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The IT professions, especially the SystemsAnalyst, deal with and use abstraction intheir day-to-day professional workSystems Analysis


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An abstraction of business processingData are representative of measurableattributes of real thingsProcesses are descriptions of actions whichare undertakenThese two are the abstractions used to modelactivities in a business context

Information System


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Information System components include:People - need the information, build the system,operate it and use itData and Information - the raw material which thesystem is set up to manage and distributeComputers - process the data and informationProcedures software and manual, that define

how the information is to beinput/stored/processed/output (formal andinformal)

IS components


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A collection of attributes sufficient for theirbusiness purposee.g .Customers pay their invoices

a) in personb) using e-commerce

The business does not need the customersphysical presence in order to receive thepayment

Information as an abstraction


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The software that receives the customersidentity, their invoice number and paymentamount and records it Is an abstraction of receiving cash money,writing it in a ledger, putting it in the drawerand stamping the invoice Paid

Information System as anabstraction


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Information systems are relatively complex:many components (data and processes)much interaction between componentssystems within systemsintangibility of information (what to record)subjectivity of information (hard to define)

Information System complexity


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Usually we dont need to know the fullcomplexity of a thing to be able to use it Television turn it on, change channels,turn it offWe dont see (and dont need) the internalworkings of the TV to make it work for us just the needed inputs and expectedoutputsWe call this the black box metaphor

Reality versus concept


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Activities involved in building computer-basedinformation systems are:analysing and describing information needs

including identifying existing informationproblemsdesigning solutions to meet those needsacquiring or building new systemsimplementing the new systems

Building Information Systems


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The context of Systems Analysis and DesignThe Systems Development Life Cycle (SDLC)Professional roles in the SDLC

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