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Jump to first page 30/06/2006 1 Chapter 1 System Development Environment
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Jump to first page 30/06/2006 2 Learning Objectives Define information systems analysis and design Describe the organizational roles involved in information systems development 1.2
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Jump to first page 30/06/2006 3 Learning Objectives Describe four types of information systems: Transaction Processing Systems (TPS) Management Information Systems (MIS) Decision Support Systems (DSS) Expert Systems (ES) Describe the information systems development life cycle (SDLC) 1.3
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Jump to first page 30/06/2006 4 Learning Objectives Discuss alternatives to the systems development life cycle Discuss the role of computer-aided software engineering (CASE) tools in systems development Discuss project management (PM) 1.4
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Jump to first page 30/06/2006 5 Introduction n What is a system ? F System is a set of components that work together in an environment for a specific function in order to achieve certain objectives. n What is information? F Information is data that has been processed or worked for a specific objective.
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Jump to first page 30/06/2006 6 Introduction n Information System u An Information System (IS) is an organization of data, processes, interfaces, networks, people, and technology which are related and support daily business operations (Data Processing) or support management in problem solving and decision making (Information Services).
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Jump to first page 30/06/2006 7 Introduction n Information Systems Analysis and Design u Complex process whereby computer- based information systems are developed and maintained n Application Software u Result of system analysis and design u Designed to support specific organizational functions or processes 1.5
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Jump to first page 30/06/2006 8 Introduction n Systems Analyst u Organizational role most responsible for analysis and design of information systems n Systems Analyst performs analysis and design based upon: u Understanding of organization’s objectives, structure and processes u Knowledge of how to exploit information technology for advantage 1.8
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Jump to first page 30/06/2006 9 Software Engineering Process n Software engineering processes have been developed to assist in analysis and design n Consists of: u Methodologies F A sequence of step-by-step approaches that help develop the information system u Techniques F Processes that the analyst follows to ensure thorough, complete and comprehensive analysis and design u Tools F Computer programs that aid in applying techniques 1.11
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Jump to first page 30/06/2006 10 Organizational Responsibilities in Systems Development n IS Manager u May have a direct role in systems development if the project is small u Typically involved in allocating resources to and overseeing system development projects n Systems Analyst u Key individuals in the systems development process
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Jump to first page 30/06/2006 11 Organizational Responsibilities in Systems Development n Skills of a Successful Systems Analyst u Analytical F Understanding of organizations F Problem solving skills F System thinking Ability to see organizations and information systems as systems u Technical F Understanding of potential and limitations of technology u Management F Ability to manage projects, resources, risk and change u Interpersonal F Effective written and oral communication skills 1.11
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Jump to first page 30/06/2006 12 Organizational Responsibilities in Systems Development n Programmers u Convert specifications into instructions that the computer understands u Write documentation and testing programs n Business Managers u Have power to fund projects and allocate resources u Set general requirements and constraints for projects 1.12
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Jump to first page 30/06/2006 13 Organizational Responsibilities in Systems Development n Other IS Managers/Technicians u Database Administrator F Involved in design, development and maintenance of databases u Network and telecommunications experts F Develop systems involving data and/or voice communications u Human Factors Specialists F Involved in training users and writing documentation u Internal Auditors F Ensure that required controls are built into the system 1.13
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Jump to first page 30/06/2006 14 Users n Users, also known as end users, are persons who are working with the system in terms of data entry, reading reports and making decisions based on the information produced by the system. n Users are normally involved in determining requirements of the system during the IS system development process.
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Jump to first page 30/06/2006 15 Management n Management is responsible for endorsing and providing project allocation for IS development in the organization. n They are also responsible for supervising and driving the SD team in order to achieve organization objectives as well as enforcing the usage of system to all members of the organization.
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Jump to first page 30/06/2006 16 Types of IS and Systems Development n Transaction Processing Systems (TPS) u Automate handling of data about business activities (transactions) n Management Information Systems (MIS) u Converts raw data from transaction processing system into meaningful form n Decision Support Systems (DSS) u Designed to help decision makers u Provides interactive environment for decision making 1.16
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Jump to first page 30/06/2006 17 Types of IS and Systems Development n Expert Systems (ES) u Replicates decision making process u Knowledge representation describes the way an expert would approach the problem 1.17
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Jump to first page 30/06/2006 18 Developing Information Systems and the SDLC n System Development Methodology u Standard process followed in an organization u Consists of: F Analysis F Design F Implementation F Maintenance
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Jump to first page 30/06/2006 19 Systems Development Life Cycle n Traditional methodology for developing, maintaining, and replacing information systems n Consists of five phases: u Planning u Analysis u Design u Implementation u Maintenance 1.19
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Jump to first page 30/06/2006 20 Systems Development Life Cycle u Phases are not necessarily sequential u Each phase has a specific outcome and deliverable u Individual companies use customized life cycles 1.20
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Jump to first page 30/06/2006 21 Phases of the Systems Development Life Cycle n Planning: u Project Identification and Selection F Two Main Activities Identification of need Prioritization and translation of need into a development schedule F Helps organization to determine whether or not resources should be dedicated to a project u Project Initiation and Planning F Two Activities Formal preliminary investigation of the problem at hand Presentation of reasons why system should or should not be developed by the organization 1.21
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Jump to first page 30/06/2006 22 Systems Development Life Cycle n Analysis u Study of current procedures and information systems F Determine requirements Study current system Structure requirements and eliminate redundancies F Generate alternative designs F Compare alternatives F Recommend best alternative 1.22
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Jump to first page 30/06/2006 23 Systems Development Life Cycle n Design u Logical Design F Concentrates on business aspects of the system u Physical Design F Technical specifications n Implementation F Hardware and software installation F Programming F User Training F Documentation 1.23
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Jump to first page 30/06/2006 24 Systems Development Life Cycle n Maintenance F System changed to reflect changing conditions F System obsolescence 1.24
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Jump to first page 30/06/2006 25 Different Approaches to Software Development n Prototyping u Building a scaled-down working version of the system u Advantages: F Users are involved in design F Captures requirements in concrete form n Rapid Application Development (RAD) u Utilizes prototyping to delay producing system design until after user requirements are clear 1.25
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Jump to first page 30/06/2006 26 Different Approaches to Software Development n Joint Application Design (JAD) u Users, Managers and Analysts work together for several days u System requirements are reviewed u Structured meetings 1.26
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Jump to first page 30/06/2006 27 Improving IS Development Productivity n Computer-aided software engineering (CASE) tools u Facilitate creation of a central repository for system descriptions and specifications 1.27
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Jump to first page 30/06/2006 28 Importance of Project Management n Project management may be the most important aspect of systems development n Effective PM helps in u Meeting customer expectations u Satisfying budget and time constraints n PM skills are difficult and important to learn
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Jump to first page 30/06/2006 29 Managing the Information Systems Project n Project u A planned undertaking of related activities to reach an objective that has a beginning and an end n Project management u A controlled process of initiating, planning, executing, and closing down a project
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Jump to first page 30/06/2006 30 Managing the Information Systems Project (cont.) n Project manager u Systems analyst with management and leadership skills responsible for leading project initiation, planning, execution, and closedown n Deliverable u The end product of an SDLC phase
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Jump to first page 30/06/2006 31 Phases of Project Management Process n Phase 1: Initiation u Assess size, scope and complexity, and establish procedures n Phase 2: Planning n Phase 3: Execution u Plans created in prior phases are put into action n Phase 4: Closedown u Bring the project to an end
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Jump to first page 30/06/2006 32 PM Phase 2: Project Planning n Define clear, discrete activities and the work needed to complete each activity n Tasks u Define project scope, alternatives, feasibility u Divide project into tasks u Estimate resource requirements u Develop preliminary schedule u Develop communication plan u Determine standards and procedures u Risk identification and assessment u Create preliminary budget u Develop a statement of work u Set baseline project plan
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Jump to first page 30/06/2006 33 Some Components of Project Planning n Statement of Work (SOW) u “Contract” between the IS staff and the customer regarding deliverables and time estimates for a system development project n The Baseline Project Plan (BPP) u Contains estimates of scope, benefits, schedules, costs, risks, and resource requirements n Preliminary Budget u Cost-benefit analysis outlining planned expenses and revenues
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Jump to first page 30/06/2006 34 Some Components of Project Planning (cont.) n Work Breakdown Structure (WBS) u Division of project into manageable and logically ordered tasks and subtasks n Scheduling Diagrams u Gantt chart: horizontal bars represent task durations u Network diagram: boxes and links represent task dependencies
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Jump to first page 30/06/2006 35 Scheduling Diagrams: Gantt Chart Special-purpose project management software is available for this.
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Jump to first page 30/06/2006 36 Scheduling Diagrams: Network Diagram Special-purpose project management software is available for this.
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Jump to first page 30/06/2006 37 Monitoring Progress with a Gantt Chart Red bars indicate critical path, lines through bars indicate percent complete.
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Jump to first page 30/06/2006 38 Representing and Scheduling Project Plans n Gantt Charts n Network Diagrams n PERT Calculations n Critical Path Scheduling
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Jump to first page 30/06/2006 39 Gantt Charts vs. Network Diagrams n Gantt charts u Show task durations u Show time overlap u Show slack time in duration n Network diagrams u Show task dependencies u Do not show time overlap, but show parallelism u Show slack time in boxes
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Jump to first page 30/06/2006 40 Gantt Charts vs. Network Diagrams (cont.)
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Jump to first page 30/06/2006 41 Estimating Task Duration n PERT: Program Evaluation Review Technique n Technique that uses optimistic (o), pessimistic (p), and realistic (r) time estimates to determine expected task duration n Formula for Estimated Time: u ET = (o + 4r + p)/6
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Jump to first page 30/06/2006 42 Example PERT Analysis
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Jump to first page 30/06/2006 43 Critical Path Scheduling n A scheduling technique whose order and duration of a sequence of task activities directly affects the completion date of a project n Critical path: the shortest time in which a project can be completed n Slack time: the time an activity can be delayed without delaying the project
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Jump to first page 30/06/2006 44 Critical Path Example (dependencies between tasks) PRECEDING ACTIVITIES indicate the activities that must be completed before the specified activity can begin (see Fig. 3.19 for time estimates).
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Jump to first page 30/06/2006 45 Network diagram provides graphical illustration of dependencies between activities (see previous slide). Critical Path Example Network diagram shows dependencies
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Jump to first page 30/06/2006 46 Determining the Critical Path n Calculate the earliest possible completion time for each activity by summing the activity times in the longest path to the activity. This gives total expected project time. n Calculate the latest possible completion time for each activity by subtracting the activity times in the path following the activity from the total expected time. This gives slack time for activities. n Critical path – contains no activities with slack time.
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Jump to first page 30/06/2006 47 Critical Path Calculation Early and late time calculations are determined and critical path established. (Note: Activity #5 can begin late without affecting project completion time).
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Jump to first page 30/06/2006 48 Critical Path Calculation (cont.) Note the slack time in Activity #5.
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Jump to first page 30/06/2006 49 Summary n Information systems analysis and design u Process of developing and maintaining an information system n Four types of information systems u Transaction Processing (TPS) u Management Information Systems (MIS) u Decision Support (DSS) u Expert Systems (ES) 1.49
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Jump to first page 30/06/2006 50 Summary n Systems Development Life Cycle (SDLC) u Planning u Analysis u Design u Implementation u Maintenance 1.50
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Jump to first page 30/06/2006 51 Summary n Alternatives to Systems Development Life Cycle u Prototyping u Rapid Application Development (RAD) u Joint Application Design (JAD) n Computer-aided software engineering (CASE) tools 1.51
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Jump to first page 30/06/2006 52 Summary n In this chapter you learned how to: Explain the process of managing an information systems project. Describe the skills required to be an effective project manager. Explain critical path scheduling, Gantt charts, and Network diagrams.
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