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Lecture on Systems Analysis
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Systems Analysis What are information systems, and who are the stakeholders in the information systems game? Define systems analysis and relate the term to the preliminary investigation, problem analysis, requirements analysis, and decision analysis phases of the systems development methodology. Describe a number of systems analysis approaches for solving business system problems. Describe the preliminary investigation, problem analysis, requirements analysis, and decision analysis phases in terms of your information system building blocks. NOTE: Although some of the tools and techniques of systems analysis are introduced in this chapter, it is not the intent of this chapter to teach those tools and techniques. This chapter teaches only the process of systems analysis. The tools and techniques will be taught in the subsequent five chapters.
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Lesson Map No additional notes
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Systems Analysis vs. Systems Design
Systems analysis is a problem-solving technique that decomposes a system into its component pieces for the purpose of studying how well those component parts work and interact to accomplish their purpose. Systems design (also called systems synthesis) is a complementary problem-solving technique (to systems analysis) that reassembles a system’s component pieces back into a complete system—hopefully, an improved system. This may involves adding, deleting, and changing pieces relative to the original system. Conversion Notes In previous editions, we used the term systems synthesis for systems design. We thought it best to change to reinforce the text title and course subject matter. Teaching Notes Systems modeling corresponds precisely with this classical definition of systems analysis and design.
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Information Systems Analysis
Information systems analysis is defined as those development phases in a project that primarily focus on the business problem, independent of any technology that can or will be used to implement a solution to that problem. Conversion Notes Technically, in this edition we return the decision analysis phase to the systems analysis chapter. At first glance, that may appear to violate the nontechnical focus of the book. In practice, this is merely a transition to technical concerns. The decision analysis phase does look at technical feasibility, but it focuses more on economic, operational, and schedule feasibility—all of which are firmly in the business domain.
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Context of Systems Analysis
Teaching Notes This context comes directly from Chapter 3. The blue processes and the blue and black data flows define systems analysis.
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Repository A repository is 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. A network directory of computer-generated files that contain project correspondence, reports, and data A CASE tool dictionary or encyclopedia (lesson-11,12) Printed documentation (binders and system libraries) An intranet website interface to the above components No additional notes
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Model-Driven Analysis Methods
Model-driven analysis emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems. Ultimately, the system model becomes the blueprint for designing and constructing an improved system. A model is a representation of either reality or vision. Just as “a picture is worth a thousand words,” most models use pictures to represent the reality or vision. Teaching Notes In previous editions, we tried to distinguish between “information systems” and “computer applications” (the latter being a subset of the former). This created more confusion with students than it was worth. Some books use the term “computer technology.” We prefer the more contemporary term, “information technology” as a superset of computer technology.
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Model-Driven Methods Structured analysis is 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. Information engineering (IE) is a model-driven and data-centered, but process-sensitive technique to plan, analyze, and design information systems. IE models are pictures that illustrate and synchronize the system’s data and processes. Object-oriented analysis (OOA) is 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. Conversion Notes We played down the methodology coverage in this edition. Several reviewers felt it was too much, too soon. In some books, information engineering is considered a “structured technique” as is structured analysis. We cannot argue this. Both methods use the same diagrammatic tools to model a system. Information engineering is more complex and comprehensive than the oversimplified presentation in this edition’s chapter. But we have found few organizations that still practice pure IE. But many organizations still practice data-driven analysis and design.
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A Simple Process Model www.assignmentpoint.com Teaching Notes
It is not the intent to teach the tool in this chapter. DFDs will be taught in Chapter 8.
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A Simple Data Model www.assignmentpoint.com Teaching Notes
It is not the intent to teach the tool in this chapter. ERDs will be taught in Chapter 7.
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A Simple Object Model +Admit() +Regsiter for Classes() +Withdraw()
+Change Address() +Calculate GPA() +Graduate() -ID Number -Name -Grade Point Average STUDENT +Create a Course() +Delete from Course Master() +Change in Course Master() -Subject -Number -Title -Credit COURSE +Add() +Drop() +Complete() +Change Grade() -Semester -Division -Grade TRANSCRIPT COURSE 1 has record for> 0..* Teaching Notes It is not the intent to teach the tool in this chapter. Object Models using the UML will be taught in Part Five, Module A.
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Accelerated Analysis Methods
Accelerated analysis approaches emphasize the construction of prototypes to more rapidly identify business and user requirements for a new system. A prototype is a small-scale, incomplete, but working sample of a desired system. Prototypes cater to the “I’ll know what I want when I see it” way of thinking that is characteristic of many users and managers. No additional notes
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Accelerated Analysis Methods
Discovery prototyping (sometimes called requirements prototyping) is used to identify the users’ business requirements by having them react to a quick-and-dirty implementation of those requirements. Rapid architecture analysis is an approach that attempts to derive system models (as described earlier in this section) from existing systems or discovery prototypes. Reverse engineering technology reads the program code for a database, application program, and/or user interface and automatically generates the equivalent system model. Teaching Notes Some might consider rapid architecture analysis to be a model-driven approach since it results in system models. We elected to classify it as an accelerated analysis approach because of the technique used to build those models. Teaching Tip Demonstrate reverse engineering to transform an Access database into a data model.
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Requirements Discovery Methods
Requirements discovery includes those techniques to be used by systems analysts to identify or extract system problems and solution requirements from the user community. Fact-finding (or information gathering) is a classical set of techniques used to collect information about system problems, opportunities, solution requirements, and priorities. Sampling Research Observation Questionnaires and surveys Interviews Joint requirements planning (JRP) techniques use facilitated workshops to bring together all of the system owners, system users, systems analysts, and some systems designer and builders to jointly perform systems analysis. Conversion Notes In this edition, we have separated joint application development (JAD) into its component parts, joint requirements planning (JRP) and joint application design (also JAD). Only JRP is applicable to this chapter.
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Business Process Redesign Methods
Business process redesign is 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. No additional notes
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Systems Analysis Phases
Preliminary Investigation Phase Problem Analysis Phase Requirements Analysis Phase Decision Analysis Phase Conversion Notes The phases correspond to the following fourth edition terms: Preliminary investigation = former survey phase Problem analysis = former study phase Requirements analysis = former definition phase Decision analysis = former configuration phase
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Preliminary Investigation Phase Context
Conversion Notes In this edition we are trying hard to reinforce the building blocks. Teaching Notes The focus system owner perspectives.
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Preliminary Investigation Phase Tasks
Teaching Notes This is called a task diagram for a phase. It is only a guideline. Each project will adapt these tasks to the project at hard. Tasks may be added, split, or deleted according to the methodology and route used. The dashed line is a control flow (as contrasted to a solid data flow). In this case, it represents a decision that determines whether the next task is necessary.
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Sample Request for System Services
Teaching Notes Not all businesses have a formal document to initiate projects.
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Problem Statements www.assignmentpoint.com Teaching Notes
Alternatively, this information could be documented in a business memo or report.
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