Systems Analysis and Design 8th Edition Chapter 11
Systems Analysis and Design 8th Edition Chapter 11 Managing Systems Implementation Phase Description 2 Systems Implementation is the fourth of five phases in the systems development life cycle Includes application development, documentation, testing, training, data conversion, and system changeover The deliverable for this phase is a completely functioning
information system Chapter Objectives 3 Explain the importance of software quality assurance and software engineering Describe the application development process for structured, object-oriented, and agile methods Draw a structure chart showing top-down design, modular design, cohesion, and coupling
Chapter Objectives 4 Explain the coding process Explain unit, integration, and system testing Differentiate between program, system, operations, and user documentation List the main steps in system installation and evaluation Chapter Objectives
5 Develop a training plan for each group of participants, compare in-house and outside training, and describe effective training techniques Describe data conversion and changeover methods Explain post-implementation evaluation and the final report to management Introduction The system design specification serves as a blueprint for constructing the new system The initial task is application development
Before a changeover can occur, the system must be tested and documented carefully, users must be trained, and existing data must be converted A formal evaluation of the results takes place as part of a final report to management 6 Software Quality Assurance Software Engineering
7 Capability Maturity Model (CMM) Capability Maturity Model Integration (CMMI) Process improvement CMMI tracks an organization's processes, using five maturity layers Software Quality Assurance
International Organization for Standardization (ISO) 8 Many firms seek assurance that software systems will meet rigid quality standards In 1991, ISO established a set of guidelines called ISO
9000-3 ISO requires a specific development plan Overview of Application Development Application development Objective is to translate the design into program and code modules that will function properly Review the System Design 9
Tasks produced an overall design and a plan for physical implementation Overview of Application Development Application development steps 10 Overview of Application Development Application Development Tasks Traditional methods
Agile Methods 11 Start by reviewing documentation from prior SDLC phases and creating a set of program designs At this point, coding and testing tasks begin Intense communication and collaboration will now begin between the IT team and the users or customers Objective is to create the system through an iterative process
Overview of Application Development System Development Tools 12 Entity-relationship diagrams Flowcharts Pseudocode
Decision tables and decision trees Overview of Application Development Project Management 13 Even a modest-sized project might have hundreds or even thousands of modules Important to set realistic schedules, meet project deadlines,
control costs, and maintain quality Should use project management tools and techniques Structured Application Development Structure Charts 14
Structure charts show the program modules and the relationships among them Control module Subordinate modules Module Data Couple Control Couple Condition Loop Structured Application Development Cohesion and Coupling
15 If you need to make a module more cohesive, you can split it into separate units, each with a single function Loosely coupled Tightly coupled Structured Application Development Drawing a Structure Chart
Step 1: Review the DFDs Step 2: Identify Modules and Relationships 16 Review all DFDs for accuracy and completeness Transform functional primitives or object methods into program modules Three-level structure charts relate to the three DFD levels
Structured Application Development Steps in Drawing a Structure Chart Step 3: Add Couples, Loops, and Conditions Step 4: Analyze the Structure Chart and the Data Dictionary 17 Identify the data elements that pass from one module to another Ensure that the chart reflects all previous documentation and that the
logic is correct Object-Oriented Application Development Object-oriented development (OOD) Characteristics of ObjectOriented Application Development 18 The application's structure is represented by the object model itself
Object-Oriented Application Development Implementation of Object-Oriented Designs Main objective is to translate object methods into program code modules and determine what event or message will trigger the execution of each module Object-Oriented Cohesion and Coupling 19
Classes loosely coupled Methods loosely coupled and highly cohesive Agile Application Development Is a distinctly different systems development method Development team is in constant communication with the customer Focuses on small teams, intense communication, and rapid development iterations Extreme Programming (XP) is one of the newest agile
methods 20 Agile Application Development An extreme programming (XP) Example 21 User story
Release plan Iteration cycle Iteration planning meeting Parallel programming Test-driven design Agile Application Development The Future of Agile Development 22
Critics claim it lacks discipline and produces systems of questionable quality Before implementing agile development, the proposed system and development methods should be examined carefully A one-size-fits-all solution does not exist Coding Coding Programming Environments Integrated development
environment (IDE) Generating Code 23 Can generate editable program code directly from macros, keystrokes, or mouse actions Testing the System
After coding, a programmer must test each program to make sure that it functions correctly Syntax errors Desk checking Logic errors Structured walkthrough, or code review Design walkthrough 24 Testing the System
Unit Testing Integration Testing System Testing 25 You should regard thorough testing as a cost-effective means of providing a quality product Testing the System Unit Testing
26 Test data Programmers must test programs that interact with other programs and files individually Stub testing Regardless of who creates the test plan, the project manager or a designated analyst also reviews the final test results Testing the System Integration Testing
27 Integration testing, or link testing Testing the programs independently does not guarantee that the data passed between them is correct A testing sequence should not move to the integration stage unless it has performed properly in all unit tests Testing the System System Testing
28 Acceptance tests You should regard thorough testing as a cost-effective means of providing a quality product If conflicting views exist, management will decide whether or not to install the system after a full discussion of the options Documentation Program Documentation
System Documentation Operations Documentation User Documentation 29 Systems analysts usually are responsible for preparing documentation to help users learn the system Documentation User Documentation
30 Effective online documentation is an important productivity tool Written documentation material also is valuable Management Approval After system testing is complete, you present the results to management If system testing produced no technical, economical, or operational problems, management determines a schedule for system installation and evaluation
31 System Installation and Evaluation Remaining steps in systems implementation: 32 Prepare a separate operational and test environment Provide training for users, managers, and IT staff Perform data conversion and system changeover
Carry out post-implementation evaluation of the system Present a final report to management Operational and Test Environments The environment that analysts and programmers use to develop and maintain programs is called the test environment The environment for the actual system operation is called the operational environment /production environment A separate test environment is necessary to maintain system security and integrity and protect the operational environment
33 Operational and Test Environments The operational environment includes hardware and software configurations and settings, system utilities, telecommunications resources, and any other components that might affect system performance If you have to build or upgrade network resources to support the new system, you must test the platform rigorously before system installation begins 34 Training
Training Plan The three main groups for training are users, managers, and IT staff You must determine how the company will provide training Vendor Training
35 Often gives the best return on your training dollars Training Webinars, Podcasts, and Tutorials 36
Webcast Subscribers As technology continues to advance, other wireless devices such as PDAs and cell phones will be able to receive podcasts Tutorials can be developed by software vendors, or by a companys IT team Training Outside Training Resources In-House Training
37 Many training consultants, institutes, and firms are available that provide either standardized or customized training packages The IT staff and user departments often share responsibility Data Conversion Data Conversion Strategies
38 The old system might be capable of exporting data in an acceptable format for the new system or in a standard format such as ASCII or ODBC If a standard format is not available, you must develop a program to extract the data and convert it Often requires additional data items, which might require manual entry Data Conversion
Data Conversion Security and Controls 39 You must ensure that all system control measures are in place and operational to protect data from unauthorized access and to help prevent erroneous input Some errors will occur It is essential that the new system be loaded with accurate, error-free data System Changeover 40
System Changeover Direct Cutover 41 Involves more risk than other changeover methods Companies often choose the direct cutover method for implementing commercial software packages Cyclical information systems usually are converted using the direct cutover method at the beginning of a quarter, calendar year, or fiscal year
System Changeover Parallel Operation 42 Easier to verify that the new system is working properly under parallel operation than under direct cutover Running both systems might place a burden on the operating environment and cause processing delay Is not practical if the old and new systems are incompatible technically
Also is inappropriate when the two systems perform different functions System Changeover Pilot Operation 43 The group that uses the new system first is called the pilot site The old system continues to operate for the entire organization After the system proves successful at the pilot site, it is
implemented in the rest of the organization, usually using the direct cutover method Is a combination of parallel operation and direct cutover methods System Changeover Phased Operation 44 You give a part of the system to all users
The risk of errors or failures is limited to the implemented module only Is less expensive than full parallel operation Is not possible, however, if the system cannot be separated easily into logical modules or segments System Changeover 45 Post-Implementation Tasks Post-Implementation Evaluation A post-implementation evaluation should examine all aspects of
the development effort and the end product the developed information system You can apply the same fact-finding techniques in a postimplementation evaluation that you used to determine the system requirements during the systems analysis phase 46 Post-Implementation Tasks Final Report to Management Your report should include the following:
47 Final versions of all system documentation Planned modifications and enhancements to the system that have been identified Recap of all systems development costs and schedules Post-Implementation Tasks Final Report to Management Your report should include the following:
48 Comparison of actual costs and schedules to the original estimates Post-implementation evaluation, if it has been performed Marks the end of systems development work Chapter Summary The systems implementation phase consists of application development, testing, installation, and evaluation of the
new system Analysts and technical writers also prepare operations documentation and user documentation Develop a training program A post-implementation evaluation assesses and reports on the quality of the new system and the work done by the project team 49 Chapter Summary The final report to management includes the final system documentation, describes any future system
enhancements that already have been identified, and details the project costs The report represents the end of the development effort and the beginning of the new systems operational life Chapter 11 complete 50
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