2 System modellingSystem modelling helps the analyst to understand the functionality of the system and models are used to communicate with customers
3 What is a model? Model – a pictorial representation of reality. Just as a picture is worth a thousand words, most models are pictorial representations of reality.
4 Models: Logical and Physical Logical model – a non technical pictorial representation that depicts what a system is or does. Synonyms with essential model, conceptual model, and business model.Physical model – a technical pictorial representation that depicts what a system is or does and how the system is implemented. Synonyms are implementation model and technical model.
5 Why Logical System Models Logical models remove biases that are the result of the way the system is currently implemented, or the way that any one person thinks the system might be implemented.
6 Why Logical System Models…. Logical models reduce the risk of missing business requirements because we are too preoccupied with technical results.Logical models allow us to communicate with end-users in non technical or less technical languages.
7 Process modeling – a technique used to organize and document a system’s processes. Flow of data through processesLogicPoliciesProcedures
8 Data flow diagram (DFD) – a process model used to depict the flow of data through a system and the work or processing performed by the system. Synonyms are bubble chart, transformation graph, and process model.DFDs have become a popular tool for business process redesign.
17 Process LogicDecomposition diagrams and data flow diagrams are effective tools for identifying processes, but are not good at showing the logic inside those processes.Eventually need to specify detailed instructions.
18 Process Logic…..Should effectively communicate with both users and programmers.Flowcharts and pseudo code are difficult for users to understand.Structured English has advantages over natural English with some of the rigor of programming logic.
19 Modeling Logic With Structured English Stuctured English is a modified form of English used to specify the logic of information system processes. Although there is no single standard, structured English typically relies on action verbs and noun phrases and contains no adjectives or adverbs.
21 Problems with Natural English Many of us do not write well, and we also tend not to question our writing abilities.Many of us are too educated to communicate with an audience that may not have had the same educational opportunities.
22 Problems with Natural English …. Some of us write everything like it was a program. If business procedures required such precision, we’d write everything in a programming language.Too often, we allow the jargon and acronyms of computing to dominate our language.
23 Problems with Natural English.… English statements frequently have an excessive or confusing scope.We overuse compound sentencesToo many words have multiple definitions.Too many statements use imprecise adjectives.Conditional instructions can be imprecise.Compound conditions tend to show up in natural English.
24 Modeling Logic With Decision Tables Structured English can become more difficult to understand and verify as logic becomes more complicated. A diagram becomes more clearer. A decision table is a diagram of process logic where logic is reasonably complicated. All the possible choices and the conditions are represented in tabular form.
26 Modeling Logic With Decision Trees A decision tree is a graphical technique that depicts a decision or choice situation as a connected series of nodes and branches. The decision tree used here is not a management science decision tree where one chooses the best among alternatives. This one is without probabilities and is used to diagram the same sort of situations for which decision tables were used.
28 Both decision tables and decision trees are used as communication tools designed to make it easier for analysts to communicate with users. How to decide whether to use Flowcharts, Structured English, Decision Tables or Decision Trees when modeling process logic depends on whichever method you prefer and understand best. But mostly it depends on task you are performing.
29 Feasibility Analysis/Assessment This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentationIn Slide Show, click on the right mouse buttonSelect “Meeting Minder”Select the “Action Items” tabType in action items as they come upClick OK to dismiss this boxThis will automatically create an Action Item slide at the end of your presentation with your points entered.Feasibility Analysis/Assessment
30 The assessment is based on an outline design of system requirements in terms of Input, Processes, Output, Fields, Programs, and Procedures. This can be quantified in terms of volumes of data, trends, frequency of updating, etc. in order to estimate whether the new system will perform adequately or not. This means that feasibility is a study based on outline.
31 Feasibility analysis is the process by which feasibility is measured. Feasibility should be measured throughout the life cycle.The scope and complexity of an apparently feasible project can change after the initial problems and opportunities are fully analyzed or after the system has been designed.Thus, a project that is feasible at one point in time may become infeasible at a later point in time.
32 Feasibility Assessment Why feasibility assessment?Information systems are major investmentsIS projects are subject to the same cost justifications as any other capital investmentsBusiness value paradox (hard to explain)Avoid "black hole" projects
33 Feasibility Checkpoints During Analysis Systems Analysis -Survey Phase``Do the problems (or opportunities) warrant the cost of a detailed study of the current system?''Systems Analysis - Study/Definition PhaseBetter estimates of development costs and the benefits to be obtained from a new system.
34 Feasibility Checkpoints … Requirements often prove to be more extensive than originally stated.If feasibility is in question, scope, schedule, and costs must be rejustified.Systems Analysis - Selection PhaseA major feasibility analysis evaluating options for the target systems design.
35 Feasibility Checkpoints … Typical options that are evaluated includeDo nothing! Leave the current system alone.Reengineer the (manual) business processes, not the computer-based processes.Enhance existing computer processes.Purchase a packaged application.
37 Tests of Feasibility…. Operational Feasibility How well will the solution work in the organization?Technical FeasibilityHow practical is the technical solution?How available are technical resources and expertise?
38 Tests of Feasibility….. Schedule Feasibility How reasonable is the project timetable?Economic FeasibilityHow cost-effective is the project or solution?Cost-benefit analysis
39 Operational Feasibility Questions to AskIs the problem worth solving?Will the solution to the problem work?How do end users and management feel about the solution?What might end-users and management resist in the new system? Can it be overcome?
40 Operational Feasibility…. Has a usability analysis been conducted?How will the working environment of users change?Operational feasibility defines the urgency of the problem and the acceptability of the solution. It should answer the following question: If the system is developed, will it be used?
41 Operational Feasibility…. Included here are:Manpower problemsManagement resistanceOrganizational conflictsLegal aspectsGovernment regulations
42 Operational Feasibility…. It evaluates whether the system can work or will work. A workable solution might fail because of end-user or management resistance.
43 Using Pieces Frame Work Performance- the system should provide adequate throughput and response timeInformation- the system should provide end users with timely, pertinent, accurate and useful information.Economy- system should offer adequate services at reduced cost.
44 Using Pieces Frame Work... Control-the system should have adequate controls to ensure confidentiality, integrity and availabilityEfficiency- make optimum use of the resources available.Services- the system should be reliable, flexible and expandable.
45 Technical Feasibility Questions to AskIs the proposed solution practical?Do we possess the necessary technology?Do we possess the necessary technical expertise?Is the technology mature enough to be applied to the problem?If technology is not available, can it be acquired?
46 Technical Feasibility…. Some people prefer state-of-art technology, but most firms prefer to use proven technology because of large customer base for obtaining advice concerning problems and continuous improvement.
47 Schedule FeasibilityTechnology could be available but not expertise, learning new technology can impact on the schedule.Are projects deadlines reasonableAre deadlines mandatory or desirableHow far can the deadlines be extendedWhat are the cost associated with such extensions in deadlines.Missed schedules are bad, but inadequate systems are worse.
48 Economic FeasibilityMany projects are economically feasible, the question to ask here is: Are the possible benefits of solving the problem worthwhile?Economic feasibility is a measure of the cost-effectiveness of a project or solution
49 Economic Feasibility… Cost-benefit analysesHow much will the system cost?Development costsOperation costsMaintenance and support costs
50 Benefit Analysis Benefit analyses Tangible benefits can be easily quantified.Measured in terms of monthly or annual savings, or of profit to organizationIntangible benefits more difficult to quantify.
51 Benefit Analysis Tangible Benefits Fewer processing errors Increased throughputDecreased response timeElimination of job stepsIncreased salesReduced credit lossesReduced expensesOpening of new marketsImprovement of Management and planningIntangible BenefitsImproved customer goodwillImproved employee moraleBetter service to communityBetter decision-makingImproved asset utilizationImproved resource control
52 Economic Feasibility Payback analysis How long will it take to recoup the costs of this project?Return on investment (ROI) analysisEstimated lifetime benefits - estimated lifetime costEstimated lifetime costNet present value analysis (translates the future income to the present value)
53 Compare candidate systems on basis of several characteristics Feasibility AnalysisCompare candidate systems on basis of several characteristicsBetter analysts always consider multiple solutions
54 Legal and Contractual Feasibility The process of assessing potential legal and contractual ramifications due to the construction of a system e.g.CopyrightLabor lawsForeign trade legislationFinancial reporting standardsOwnership of softwareLicense agreement for software and hardware
55 Market and Real Estate Feasibility Market Feasibility Study typically involves testing geographic locations for a real estate development project, and usually involves parcels of real estate land. Developers often conduct market studies to determine the best location within a jurisdiction, and to test alternative land uses for a given parcels.Market Feasibility takes into account the importance of the business in the selected area.
56 Resource FeasibilityThis involves questions such as how much time is available to build the new system, when it can be built, whether it interferes with normal business operations, type and amount of resources required, dependencies, etc. Contingency and mitigation plans should also be stated here.
57 Cultural FeasibilityIn this stage, the project's alternatives are evaluated for their impact on the local and general culture. For example, environmental factors need to be considered and these factors are to be well known. For example, religion, language, believes, signs and symbols, mannerism, timeliness.Further an enterprise's own culture can clash with the results of the project. People could have been benefiting from inefficiencies.
58 Political Feasibility The process of evaluating how key stakeholders within the organization view the proposed system e.g.New system may affect distribution of powerStake holders may take steps to block, disrupt or change the intended focus of the system