Systems Analysis And Design PDF

Assuming the Role of the Systems Analyst 1 Systems Analysis and Design Kendall & Kendall © Pearson Prentice Hall  Learning Objectives Recall the basic types of computer-based systems that a systems analyst needs to address Understand how users wo...

Assuming the Role of the Systems Analyst 1 Systems Analysis and Design Kendall & Kendall © Pearson Prentice Hall  Learning Objectives Recall the basic types of computer-based systems that a systems analyst needs to address Understand how users working in context with new technologies change the dynamics of a system Realize what the many roles of the systems analyst are Know the steps of the SDLC as they relate to HCI and how to apply them to a real system Understand what CASE tools are and how they help a systems analyst Explore other methodologies such as object-oriented systems design and prototyping Kendall & Kendall 1-2  Information – A Key Resource Fuels business and can be the critical factor in determining the success or failure of a business Needs to be managed correctly Managing computer-generated information differs from handling manually produced data Kendall & Kendall 1-3  Systems Analysts Recommend, Design, and Maintain Many Types of Systems for Users Transaction Processing Systems (TPS) Office Automation Systems (OAS) Knowledge Work Systems (KWS) Management Information Systems (MIS) Decision Support Systems (DSS) Expert Systems (ES) Executive Support Systems (ESS) Group Decision Support Systems (GDSS) Computer-Supported Collaborative Work Systems (CSCWS) Kendall & Kendall 1-4  A systems analyst may be involved with any or all of Strategic these systems at Level each organization level Higher Level Knowledge Level Operational Level As we move from the bottom to the top, each level represents a higher level of decision support. The bottom level or organizational level supported by TPS provides very structured decision support while the top level or strategic level supported by ESS, GDSS and CSCWS provides semi-structured and unstructured decision support. Kendall & Kendall 1-5  Operational Level Transaction Processing System (TPS) Process large amounts of data for routine business transactions Boundary-spanning Support the day-to-day operations of the company Examples: Payroll Processing, Inventory Management Kendall & Kendall 1-6  Knowledge Level Office Automation System (OAS) Supports data workers who share information, but do not usually create new knowledge Examples: Word processing, Spreadsheets, Communication through voice mail, Email Knowledge Work System (KWS) Supports professional workers such as scientists, engineers, and doctors Examples: computer-aided design systems, virtual reality systems (military training) Kendall & Kendall 1-7  Higher Level Management Information System (MIS) Support a broad spectrum of organizational tasks including decision analysis and decision making Examples: profit margin by sales region, expenses vs. budgets Decision Support System (DSS) Aids decision makers in the making of decisions Examples: financial planning with what-if analysis Expert System (ES) Captures and uses the knowledge of an expert for solving a particular problem which leads to a conclusion or recommendation Examples: MYCIN is an expert system was designed to identify bacteria causing severe infections and to recommend antibiotics, with the dosage adjusted for patient's body weight Kendall & Kendall 1-8  Strategic Level Executive Support System (ESS) Helps executives by providing graphics to make unstructured strategic decisions in an informed way Examples: drill-down analysis, For example, when viewing your company's total worldwide sales for each month of this year, you might drill down to see October's sales by country, then again to see October's sales in Afghanistan by product and so on. Group Decision Support System (GDSS) Permit group members to interact with electronic support “group think” Examples: email, Lotus Notes For example: brainstorming, and scenario creation Computer-Supported Collaborative Work System (CSCWS) CDCWS is a more general term of GDSS May include software support called “groupware” for team collaboration via network computers Example: video conferencing, Web survey system Kendall & Kendall 1-9  Integrating New Technologies into Traditional Systems Ecommerce and Web Systems Enterprise Resource Planning Systems Wireless Systems Open Source Software Kendall & Kendall 1-10  Figure 1.2 Systems analysts need to be aware that integrating technologies affects all types of systems Kendall & Kendall 1-11  Ecommerce and Web Systems Benefits Increasing user awareness of the availability of a service, product, industry, person, or group The possibility of 24-hour access for users Improving the usefulness and usability of interface design Creating a system that can extend globally rather than remain local, thus reaching people in remote locations without worry of the time zone in which they are located Kendall & Kendall 1-12  Enterprise Resource Planning Systems (ERP) Performs integration of many information systems existing on different management levels and within different functions Instituting ERP requires enormous commitment and organizational change. Example: Oracle Kendall & Kendall 1-13  Wireless Systems System analyst may be asked to design standard or wireless communication networks that integrate voice, video and email into organizational intranets or industry extranets System analyst may also be asked to develop intelligent agents Intelligent agents are software that can assist users with tasks in which the software learns preferences from of users over time and then acts on those preferences. Wireless communication is referred as m- commerce (mobile commerce) Kendall & Kendall 1-14  Open Source Software An alternative of traditional software development where proprietary code is hidden from the users Open source software is free to distribute, share and modify Characterized as a philosophy rather than simply the process of creating new software Example: Linux Operating System, Apache Web Server, Mozilla Firefox Web browser Kendall & Kendall 1-15  Need for Systems Analysis and Design Installing a system without proper planning leads to great user dissatisfaction and frequently causes the system to fall into disuse Lends structure to the analysis and design of information systems A series of processes systematically undertaken to improve a business through the use of computerized information systems Kendall & Kendall 1-16  Roles of the Systems Analyst The analyst must be able to work with people of all descriptions and be experienced in working with computers Three primary roles: Consultant (from outside) a fresh perspective that other people in an organization do not possess, but …… Supporting Expert (inside) expertise concerning computer hardware and software and their uses in the business Serves as a resource for those who are working on and managing other projects Agent of change a catalyst for change, develops a plan for change, and works with others in facilitating that change Kendall & Kendall 1-17  Qualities of the Systems Analyst Problem solver views the analysis of problems as a challenge and enjoys devising workable solutions Communicator Need enough computer experience to program, to understand the capabilities of computers, glean information requirements from users, and communicate what is needed to programmers. Strong personal and professional ethics Self-disciplined and self-motivated must be able to coordinate other people as well as innumerable project resources Kendall & Kendall 1-18  Systems Development Life Cycle (SDLC) The systems development life cycle is a phased approach to solving business problems Developed through the use of a specific cycle of analyst and user activities Each phase has unique user activities Kendall & Kendall 1-19  Figure 1.3 The seven phases of the systems development life cycle Kendall & Kendall 1-20  Incorporating Human-Computer Interaction (HCI) Considerations The demand for analysts who are capable of incorporating HCI into the systems development process keeps increasing, as companies begin to realize that the quality of systems and the quality of work life can be improved by taking a human-centered approach at the outset of a project Kendall & Kendall 1-21  Incorporating Human-Computer Interaction (HCI) Considerations Adopting HCI principles examines a variety of user needs: physical or ergonomic factors usability factors pleasing, aesthetic and enjoyable aspects behavioral aspects Kendall & Kendall 1-22  Identifying Problems, Opportunities, and Objectives Activity: Interviewing user management Summarizing the knowledge obtained Estimating the scope of the project Documenting the results Output: Feasibility report containing problem definition and objective summaries from which management can make a decision on whether to proceed with the proposed project Kendall & Kendall 1-23  Determining Human Information Requirements Activity: Interviewing Sampling and investing hard data Questionnaires Observe the decision maker’s behavior and environment Prototyping Learn the who, what, where, when, how, and why of the current system Output: Analyst understands how users accomplish their work when interacting with a computer; and begin to know how to make the new system more useful and usable. The analyst should also know the business functions and have complete information on the people, goals, data and procedure involved Kendall & Kendall 1-24  Analyzing System Needs Activity: Create data flow diagrams Complete the data dictionary Analyze the structured decisions made Prepare and present the system proposal Output: Recommendation on what, if anything, should be done Kendall & Kendall 1-25  Designing the Recommended System Activity: Design procedures for data entry Design the human-computer interface Design system controls Design files and/or database Design backup procedures Output Model of the actual system Kendall & Kendall 1-26  Developing and Documenting Software Activity: System analyst works with programmers to develop any original software Works with users to develop effective documentation Programmers design, code, and remove syntactical errors from computer programs Document software with help files, procedure manuals, and Web sites with Frequently Asked Questions Output: Computer programs System documentation Kendall & Kendall 1-27  Testing and Maintaining the System Activity: Test the information system System maintenance Maintenance documentation Output: Problems, if any Updated programs Documentation Kendall & Kendall 1-28  Implementing and Evaluating the System Activity: Train users Analyst plans smooth conversion from old system to new system Review and evaluate system Output: Trained personnel Installed system Kendall & Kendall 1-29  Figure 1.4 Some researchers estimate that the amount of time spent on systems maintenance may be as much as 60 percent of the total time spent on systems projects Kendall & Kendall 1-30  The Impact of Maintenance Maintenance is performed for two reasons Removing software errors, and Enhancing existing software Over time the cost of continued maintenance will be greater than that of creating an entirely new system. At that point it becomes more feasible to perform a new systems study Reasons for enhancing existing software: users request additional features business changes over time hardware and software change Kendall & Kendall 1-31  Figure 1.5 Resource consumption over the system life Kendall & Kendall 1-32  Approaches to Structured Analysis and Design and to the Systems Development Life Cycle Traditional systems development life cycle CASE systems development life cycle Object-Oriented Systems Analysis and Design Kendall & Kendall 1-33  Case Tools CASE tools are productivity tools for systems analysts that have been created explicitly to improve their routine work through the use of automated support Reasons for using CASE tools Increasing Analyst Productivity Improving Analyst-User Communication Integrating Life Cycle Activities Accurately Assessing Maintenance Changes Kendall & Kendall 1-34  Case Tool Classifications Upper CASE tools perform analysis and design Lower CASE tools generate programs from CASE design Integrated CASE tools perform both upper and lower CASE functions Kendall & Kendall 1-35  Upper CASE Tools Create and modify the system design Help in modeling organizational requirements and defining system boundaries Can also support prototyping of screen and report designs Kendall & Kendall 1-36  Lower CASE Tools Lower CASE tools generate computer source code from the CASE design Source code is usually generated in several languages Kendall & Kendall 1-37  Figure 1.7 Traditional versus CASE systems development life cycle Kendall & Kendall 1-38  Object-Oriented Systems Analysis and Design Alternate approach to the structured approach of the SDLC that is intended to facilitate the development of systems that must change rapidly in response to dynamic business environments Analysis is performed on a small part of the system followed by design and implementation. The cycle repeats with analysis, design and implementation of the next part and this repeats until the project is complete Kendall & Kendall 1-39 Alternate Approaches to Structured Analysis and Design and to the Systems Development Life Cycle Agile approach - Has specific philosophy, practices and values to address rapidly changing user requirements Prototyping – offered as a response to the long development times associated with the SDLC approach and to the uncertainty often surrounding user requirements. Project champion approach – adopts the strategy of involving one person from each area affected by the system to ensure the system’s success. Multiview – a way to organize and use elements of several competing methodologies. Kendall & Kendall 1-40  Summary Information is a key resource Systems analysts deal with many types of information systems Integration of traditional systems with new technologies Roles and qualities of the systems analyst The systems Development Life Cycle CASE tools Alternatives to structured analysis and design and to the SDLC Kendall & Kendall 1-41