ITC 2374 - Chapter 2 - 2024.pdf

Chapter 2: SYSTEMS ANALYSIS  Chapter 2: Systems Analysis Define systems analysis Describe a number of systems analysis approaches for solving business system problems. Describe the phases of the system analysis: scope definition, problem analysis, requirements analysis...

Chapter 2: SYSTEMS ANALYSIS  Chapter 2: Systems Analysis Define systems analysis Describe a number of systems analysis approaches for solving business system problems. Describe the phases of the system analysis: scope definition, problem analysis, requirements analysis, logical design, and decision analysis Systems Analysis vs. Systems Design Systems analysis – The study of a business problem domain to recommend improvements and specify the business requirements and priorities for the solution. Systems design – The specification or construction of a technical computer- based solution for the business requirements identified in a system analysis. Context of Systems Analysis  Repository Repository – a location (or set of locations) where systems analysts, systems designers, and system builders keep all of the documentation associated with one or more systems or projects. System Analysis Approaches 1. Model-Driven Analysis Approaches 2. Accelerated Systems Analysis Approaches 3. Requirements Discovery Methods 4. Business Process Redesign Methods 5. Fast Systems Analysis Strategies 1. Model-Driven Analysis Approaches (1) Model-driven analysis – a problem-solving approach that emphasizes the drawing of pictorial system models to communicate business problems, requirements and solutions. Model – a representation of either reality or vision. Since “a picture is worth a thousand words,” most models use pictures to represent the reality or vision. Examples for such models: Flowcharts Structure or hierarchy charts Organization charts Ultimately, the system model becomes the blueprint for designing and constructing an improved system. Today, model-driven approaches are almost always enhanced by the use of automated tools, Visio Professional System Architect Rational Rose and so on. 1. Model-Driven Analysis Approaches (2) Three different types. a. Structured Analysis b. Information Engineering (IE) c. Object-oriented Analysis (OOA) a. Structured Analysis (1) a model-driven, process-centered technique used to either analyze an existing system, define business requirements for a new system, or both. The models are pictures that illustrate the system’s component pieces: processes and their associated inputs, outputs, and files. One of the most widely practiced approaches Focuses on the flow of data through business and software processes. “Process-Centered Approach”  a. Structured Analysis (2) System Analysts draw the process models These process models serve as blueprints for business processes to be implemented and software to be purchased or constructed Process models are called “Data Flow Diagrams” An example for a Data Flow Diagram (Simple Process Model)  b. Information Engineering A model-driven and data-centered, but process- sensitive technique for planning, analyzing, and designing information systems. IE models are pictures that illustrate and synchronize the system’s data and processes. IE focused on the structure of stored data in a system “Data-centered Approach” System analysts draw these data models. Data models are called “Entity Relationship Diagrams” An example for a Entity Relationship Diagram (A Simple Data Model) Object-oriented Analysis (1) Object-oriented analysis (OOA) – a model- driven technique that integrates data and process concerns into constructs called objects. OOA models are pictures that illustrate the system’s objects from various perspectives such as structure and behavior, and interactions of the objects. UML for Object Model: The Unified Modeling Language (UML) provides a graphical syntax for an entire series of object models A Simple Object Model 2. Accelerated Systems Analysis Accelerated systems analysis approaches emphasize the construction of prototypes to more rapidly identify business and user requirements for a new system. prototype – a small-scale, incomplete, but working sample of a desired system.  3. Requirements Discovery Methods Requirements discovery – the process, used by systems analysts of identifying or extracting system problems and solution requirements from the user community. Approaches include: Fact-finding – the process of collecting information about system problems, opportunities, solution requirements, and priorities. Sampling of existing documentation, reports, forms, databases, etc Research of relevant literature Observation of the current system Questionnaires and surveys Interviews Joint requirements planning (JRP) – the use of facilitated workshops to bring together all of the system owners, users, and analysts, and some systems designer and builders to jointly perform systems analysis. 4. Business Process Redesign Business process redesign (BPR) – the application of systems analysis methods to the goal of dramatically changing and improving the fundamental business processes of an organization, independent of information technology.  5. Fast Systems Analysis Strategies: Agile Method Agile method – the integration of various approaches of systems analysis and design for applications as deemed appropriate to the problem being solved and the system being developed. Most commercial methodologies do not impose a single approach (structured analysis, IE, OOA) on systems analysts. Instead, they integrate all popular approaches into a collection of agile methods. System developers are given the flexibility to select from a variety of tools and techniques to best accomplish the tasks at hand, The hypothetical FAST methodology operates this way. FAST Systems Analysis Phases 1. Scope Definition Phase Is the project worth looking at? 2. Problem Analysis Phase Is a new system worth building? 3. Requirements Analysis Phase What do the users need and want from the new system? 4. Logical Design Phase What must the new system do? 5. Decision Analysis Phase What is the best solution? 1. Scope Definition Phase (1) This phase is intended to be quick. (Not exceed 2 or 3 days for most projects) Important tasks, Identify Preliminary problems, opportunities & directives Define the boundary of the project Develop the preliminary project plan Consists of schedules and budgets Prepare the project charter Key output of the scope definition phase project charter.  1. Scope Definition Phase (2) Project Charter, It is a document. It includes various elements that define the project in terms of participants, problems, opportunities, and directives, scope, methodology, statement of work to be completed, deliverables, quality standards, schedule and budget. It should be added to the project website for all to see.  2. The Problem Analysis Phase (1) Thoroughly analyze the problems, opportunities and directives that identified in the previous phase. Important tasks, Study the problem domain (regarding business problems, opportunities, directives and constraints etc.) Use fact-finding techniques (i.e. conduct interviews, document findings, JRP (Joint Requirements Planning) sessions. Analyze problems & opportunities Analyze business processes (use DFD models) Update or refine the project plan Communicate the finding & recommendations to the business community Ways to communicate Presenting at a meeting Publishing on the Intranet Key output: updated project plan  3. The Requirement Analysis Phase (1) Defines the business requirements for a new system. Important tasks, Identify and express system requirements This can be done by translating the objectives into the functional & nonfunctional requirements that will be needed to meet the objectives. Prioritize system requirements Update or refine the project plan Communicate the requirements statement to the business community. Key output: Business Requirement statement 4. The Logical Design Phase In this phase we draw various system models to document the requirements for a new and improved system. Examples for such models, Data structures Business processes Data Flows User Interfaces Key output: Business Requirements Statement (using system models)  5. The Decision Analysis Phase (1) The purpose of the decision analysis phase is to identify candidate solutions, analyze those candidate solutions and recommend a target system that will be designed, constructed and implemented. Important tasks, Identify candidate (alternative) solutions for the problem Analyze the candidate solutions & select the optimal one. Each candidate system solution must be analyzed for feasibility Communicate the optimal solution to the Business community. Prepare a system proposal. Key output: “System Proposal” that will fulfill the business requirements identified in the previous phase. 5. The Decision Analysis Phase (2) Four types of Feasibility, Technical feasibility – Is the solution technically practical? Does our staff have the technical expertise to design and build this solution? Operational feasibility – Will the solution fulfill the users’ requirements? To what degree? How will the solution change the users’ work environment? How do users feel about such a solution? Economic feasibility – Is the solution cost-effective? Schedule feasibility – Can the solution be designed and implemented within an acceptable time period?  Outline Outlinefor foraaTypical Typical System Proposal System Proposal I. Introduction A. Purpose of the report B. Background of the project leading to this report C. Scope of the report D. Structure of the report II. Tools and techniques used A. Solution generated B. Feasibility analysis (cost-benefit) III. Information systems requirements IV.Alternative solutions and feasibility analysis V. Recommendations VI.Appendices