Transcript CHAPTER 5
ANALYSIS PHASE OF BUSINESS SYSTEM DEVELOPMENT METHODOLOGY INTRODUCTION System Analysis – is a term that describes the early phases of systems development. problem solving technique that decomposes a system into its component pieces for the purpose of studying how well those component parts work & interact to accomplish their purposes. System analysis approaches There are 4 system analysis approaches; Model driven analysis approach Accelerated analysis approach Requirements discovery methods Business process redesign methods Model Driven Analysis Approaches Emphasizes the drawing of pictorial system models to document & validate both existing & proposed system. The system model becomes the blueprint for designing & constructing an improved system. Example of software : VISIO Structures Analysis Was one of the first formal approach for system analysis of business information system. Used to either analyze an existing system, define business requirements for new system or both. Model Driven Analysis Approaches Information Engineering Model driven & data centered approach to plan, analyze & design information systems. Consists of pictures that illustrate & synchronize the system’s data & processes. Said to be data-centered paradigm because it emphasizes the study & requirement analysis of data requirements before those of the process & interface requirements. This is based on the belief that data is a corporate resources that should be planned & managed. Model Driven Analysis Approaches Object Oriented Analysis Is a technique that integrates data & process concerns into constructs called objects. Consists of pictures that illustrates the system’s objects from various perspectives such as structure & behaviour. Unified Modeling Language (UML) provides a graphical syntax for an entire series of object models. Accelerated Analysis Approaches Emphasize the construction of prototypes by rapidly identifying business & user requirements for a new system. Emphasizes the interface building blocks in the information system framework by constructing sample forms & reports. Prototype – a small scale, incomplete but working sample of desired system. Accelerated Analysis Approaches Discovery Prototyping Uses rapid development technology to help users discover their business requirements by having them reach to quickand- dirty implementation of those requirements. Rapid Architecture Analysis An accelerated analysis approach that also builds a system models. Attempts to derive system models from existing systems or discovery prototype. It is made possible by reverse engineering technology that is included in many tools such as CASE & programming languages. Accelerated Analysis Approaches Reverse engineering technology reads the program code for an existing database, application program, user interface & automatically generates the equivalent system model. The resulting system model can be further edited by system analyst & users to provide a blueprint for a new & improved system. Requirement Discovery Methods Includes those techniques to be used by system analyst to identify or extract system problems & solution requirements from the user community. Fact-finding Techniques An essential skill for all system analysts. Classical set of techniques used to collect information about system problems, opportunities, solution requirements & priorities. Accelerated Analysis Approaches Fact finding techniques; Sampling of existing documentation, reports, forms, memos Research of relevant literature, site visits Observation on the current system & work environment Questionnaires & surveys of the management & users Interviews of the appropriate managers, users & technical staffs. Business Process Redesign Methods Business process redesign – the application of system analysis methods to the goal of dramatically changing & improving the fundamental business processes of an organization, independent of information technology. Suitable for a study of existing business processes to identify problems & inefficiencies that is addressed in requirements for new / improved system. The Preliminary Investigation Phase Investigation is done by system analyst to study the systems request & recommend specific action. The analyst gathers fact about the problem / opportunity, project scope & constraints, project benefits & estimated development time & cost. The end product of the investigation is a report to the management. Steps in the Preliminary Investigation Step 1: Understand the problem / opportunity Step 2: Define project scope & constraints Step 3: Performs fact-finding Step 4: Determine feasibility Step 5: Estimate development time & cost Step 6: Present result/recommendation to management Steps in the Preliminary Investigation Step 1: Understand the problem / opportunity System analyst might need to develop a business profile. Analyst will need to understand & know how the modifications will affect the business operation or system even when it’s a small alteration. Step 2: Define the project scope & constraints Means to define boundaries/extent of the project being as specific as possible. Projects that expands gradually without specific authorization is called = project creep Steps in the Preliminary Investigation Types of constraints ; present, future, internal, external, mandatory & desirable. Step3: Perform fact-finding Analyst will perform this step using various techniques such as; Analyze organization charts – to understand how departments functions & identify the individual involved Conduct interview – interviewing the identified individual. Review current documentation – analyst should check whether the documentation received is accurate & complete Observe operation – use statistic technique to check the frequency Carry out a user survey – especially when it involves larger group. Steps in the Preliminary Investigation Step4 : Determine feasibility To determine economic feasibility. Step5 : Estimate time & cost To determine cost & time the following need to be addressed: What information needed & how to gather & analyze? Source of information to use & the constraints to use it? How many will be interviewed & how much time & cost for it. How much cost to alayze the information gathered & prepare final report. Steps in the Preliminary Investigation Step6 : present results & recommendations to management If minor problem then recommendation is given without further analysis, but if the problem is big then further analysis is needed (development phase) Problem Analysis Phase Provides the analyst a better understanding of the problems, opportunities & directives that triggered the project. The goal of this phase is to study & understand the problem domain well enough to analyze its problems, opportunities & constraints. Steps in Problem Analysis Phase Analyst must follow a series of steps: Step 1 – study the problem domain Step2 – analyze problems & opportunities Step3 – analyze business process Step4 – establish system improvement objectives Step 5- update the project plan Step 6 – present findings & recommendations to management Steps in Problem Analysis Phase Step 1 – study the problem domain Attempts to learn about the current system Step2 – analyze problems & opportunities To perform this step, project team must work with system owners & system users Cause & effect analysis is a technique in which problems are studied to determine their causes & effects. Steps in Problem Analysis Phase Step3 – analyze business process Analyze business needs – to clearly define the business & system requirements. Define business solution – IT experts define in the form of programs 7 databases, business people define in procedures to fulfill business mission. Test business solution – evaluating whether the solution fulfills the business need. Step4 – establish system improvement objectives Any improvement to the system will be measured & constraints identified. Criteria for success measured in term of objectives Steps in Problem Analysis Phase Step 5 – update the project plan This task is triggered by completion of the system improvement objectives. Initial project plan = input, updated project plan = output Step 6 – present findings / recommendations This task is triggered by the completion of the updated project plan. Requirements Analysis Phase Defines the business requirements for a new system. Final deliverables & milestones is to produce a business requirements statement that will fulfill the system improvement objectives. Steps in Requirements Analysis Phase Steps are as follows: Step 1 – define requirements Step2 – analyze functional requirements Step3 – trace & complete requirements Step4 – prioritize requirements Step5 – update the project plan Step6 – outgoing requirement management Steps in Requirements Analysis Phase Step1 : define requirements A functional requirement – a description of activities & services a system must provide (input, output, stored data & processes) Non functional requirement – description of other features, characteristics & constraints that define a satisfactory system (performance, budgets, cost) Step2 : Analyze functional requirements System modeling – graphical representation of concept or process that system developers can analyze, test & modify Prototyping – creation of early working version of the information system or its components. Steps in Requirements Analysis Phase Step3 – Trace & complete requirements Tracing each system model / prototype back to the functional requirement to ensure all functional requirements are fulfilled. Step4 – prioritize requirements Timeboxing – technique that delivers information system’s functionality & requirements through versioning. Steps in Requirements Analysis Phase Step5 : update the project plan The completed business requirements statement completes the task, as well as the requirement analysis phase. Step6 : ongoing requirement management Requirement management defines a process for everyone involved in the system development that specifies how changes are to be requested & documented, how to be logged & tracked, etc Decision Analysis Phase Identifies candidate solutions, analyses those candidate solutions & recommends a target system that will be designed, constructed & implemented. Steps in Decision Analysis Phase Steps are as follows ; Step1 – identify candidate solutions Step2 – analyze candidate solutions Step3 – compare candidate solutions Step4 – update the project plan Step5 – recommend a system solution Steps in Decision Analysis Phase Step 1: identify candidate solution System owners & users may not be directly involved in the task, but they may contribute ideas & opinions that start the task. Step2: analyze candidate solution Each candidate solution must be analyzed for feasibility. 4 criteria: Technical feasibility Operational feasibility Economic feasibility Schedule feasibility Steps in Decision Analysis Phase Step3 : Compare candidate solution The deliverables of this task is the solutions to be recommended. If more than one solution is recommended, priorities should be established. Step4 : update the project plan System analyst are adjusting scope accordingly, so based on the solution recommended, analyst should reevaluate project scope & update project plan accordingly Steps in Decision Analysis Phase Step6 : Recommend a solution This task is triggered by the completion of the updated project plan.