Management Information Systems - 5 Analysis & Design of Systems
After the programmers have completed coding the system specifications, the three stages of unit, system and acceptance testing begin. Acceptance is the final stage of testing to approve the system for release into a live environment. Unit testing checks each program and system testing checks the system as a whole to ensure that all the modules work together.
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Although the traditional SDLC is still used for developing large formal systems, the main drawbacks with this approach is that it is expensive, time-consuming and inflexible. As the flow of activity is one way, the specifications of a project are determined at an early stage and it would be complex to change them at a later date. Hence, this leads to inflexibility in the scope of theproject.
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An information system can be constructed from an application software package that is purchased orleased, and used as-is or customized to meet the needs of the organization. These prewritten software packages may meet the needs of an organization and will offer time and cost savings as long as extensive customization is not required.
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BPR has a high failure rate but many companies still attempt it because the rewards are potentially outstanding. The failure rate is high because most companies cannot manage the major organizational change needed for a successful redesign.
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CASE tools are applications that automate some or all of the steps in the Systems Development Life Cycle (SDLC). CASE stands for Computer Aided Software Engineering.
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End-user development came about because of improvements in computer education, inexpensive hardware, prewritten software tools and backlog of information services work. The result of good computer education started to impact the workplace in the 1980s with management officers possessing reasonable computer skills.
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End-user development refers to the development of information systems by end users using 4th generation tools with virtually no aid or no aid at all from technical specialists. 4th Generation tools enable users with little or no formal information technology training to build software programs. End-user development is also known as end-user computing (EUC).
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In order to make the most of end-user development, organizations need to assess the costs involved and create guidelines for the use of hardware and software as well as setting quality standards for these projects. This is critical as a sub-standard system may result in system failure.
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JAD is one of the methods for speeding up the development process by heavily involving the end users with the developers at the design stage in organized and managed interactive sessions. Joint Application Design (JAD) is a technique useful to both developers and end users.
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Many companies today adopt a combined approach to developing new systems that encompasses elements of traditional SDLC, RAD and prototyping, and this method is called phased development. Phased development is a fairly popular approach adopted by companies today.
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Object-oriented development is best suited for a fast-changing organizational environment and creation of web applications. Web applications need to be regularly updated, altered, and improved. Since the objects are reusable, the creation of new applications or alteration of existing applications to adapt to the changes can easily be organized by reusing, changing, or adding some objects.
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One of the key differences between RAD and traditional SDLC is that the RAD processes do not have to be carried out sequentially. This is a key feature of RAD and the steps in development do not follow a particular flow; some of the processes can happen simultaneously.
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Outsourcing is not the right option for every organization and the drawbacks include a perceived loss of control over their information systems, hidden costs in finding a suitable vendor and moving to the newsystem, as well as monitoring to ensure that they are getting the services they paid for. Companies should keep an eye on the services delivered by the outsourcing vendor to ensure that they are delivering quality service in accordance with the contractual agreement.
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Over recent years, the practice of outsourcing has become popular with many companies primarily because of the resultant cost savings of hiring external specialists to construct, manage, or operate information systems. By outsourcing, a company does not have to maintain a large staff of information specialists or an IT center. They only need to hire core IT personnel.
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Planning, analysis, design, implementation, and use are the 5 stages in the traditional SDLC. Implementation is the 4th stage in the traditional SDLC (System Development Life Cycle).
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Prototyping is another form of systems development where the developers quickly and inexpensively build an experimental system which is reviewed by the end users for comments and suggestions before construction of the final version is executed.
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Reengineering means completely redesigning the system without preserving any of the original functionality, but the experience derived from the original system is used in creating the new one. The development of the new system after engaging in reengineering is also called forward engineering and follows the normal SDLC pattern.
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Restructuring refers to the process of changing one system into another form while preserving the functionality of the original system. This occurs particularly when a legacy system works very well but is no longer cost effective to maintain. Hence, by restructuring, a new system with similar functionality is created but using more modern hardware and software.
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Some companies have stated that they chose outsourcing because it enabled them to focus on their core business and not worry about maintaining computers and designing systems. Outsourcing became popular in the 1990s because of the increasing standardization of IT services, the desire to cut costs, the inability to hire IT workers, and the need to focus on core business management.
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The 2 types of prototypes are the evolutionary prototype and the requirements prototype. The requirements prototype is utilized when the end users are not entirely sure of the systems requirements. Hence, the prototype is used for them to refine their needs. When this is done, the prototype is discarded and the project to build the system is launched. The evolutionary prototype on the other hand is constantly refined until it serves the end users' purposes and becomes the actual system.
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The 4 main components of RAD are management, people, methodologies and tools. RAD tools are primarily 4th generation languages and tools that transform documentation into working software.
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The BPR components can be used separately or in combination and the route that should be chosen will depend on the present system state and the functional and technical quality of that system. Technical quality refers to how well the system performs technically. Functional quality refers to how well a system does what is does.
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The advantages to prototyping are that it can be produced quickly, encourages active communication between the end users and developers (meaning the developers can create a system that meets the end users' needs), and ensures that implementation is smoother since the end users know what to expect. Implementation will be quicker and easier since the end users have played an active role in the creation of the system.
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The application services tier of web services consists of particular business applications like credit card processing and production scheduling. Credit card processing is an example of a specific business application that is housed in this third tier.
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The benefits of end-user development include the speedy construction of information systems, high satisfaction levels since the end users are creating a product that suits their needs, and raised development productivity. Companies are reporting increased productivity rates from end-user development.
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The conversion phase of systems development refers to the changing of systems. This occurs when the old system is removed and the new one installed.
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The growing popularity of the Internet will mean that more and more applications will be constructed using web services that deliver plug and play functionality. Web services are software components delivered via the web to facilitate the communication between applications without the need for translation.
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The key advantages to outsourcing are the ability to find competitive and highly skilled specialists, cost benefits from external management and maintenance of information systems, as well as flexibility when an organizations needs are variable. Some organizations needs are not static but change regularly. By outsourcing, organizations can pay for what they need rather than invest heavily in the necessary labor, hardware and software.
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The main disadvantage of end-user development is that there may be a lack of appropriate testing and documentation since the normal mechanisms for development have been excluded. Since the development takes place extremely quickly and the normal lifecycle for development is not followed, it is likely that there has been minimal testing and documentation.
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The main drawbacks to prototyping are that in producing a prototype speedily, proper design and development procedures may have been overlooked, thereby producing an unsatisfactory result. If theprototype turns out well, then it may lift the end users' expectations to unrealistic levels. This may cause the end users to expect too much from the developers, which could potentially cause a problem with the end users' requirements for the project.
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The main objective of prototyping is to create a working version of the system as quickly as possibleeven if some features are not included in the early versions. The major advantage of prototyping is that users receive a working system much sooner than they would with the SDLC method.
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The object oriented system development approach is similar to the traditional SDLC approach in that there are organized phases but differs in that it is more repetitive and incremental. With object-oriented programming, the object is the standard unit of development, combining both data and actions.
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The plug and play architecture has 3 tiers: standards and protocols, the service grid, and application services. The service grid of the web services architecture forms the vital environment necessary to enable the execution of necessary business activities and this includes shared utilities, billing and payment systems and security.
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The process of quickly delivering a working system without sacrificing quality is known as RAD (Rapid Application Development).
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The production and maintenance stage begins following implementation of the new system and denotes the period when alterations are made, errors are corrected, new requirements are met and processing efficiencies are gained. Most systems will have bugs that have slipped through the net despite extensive testing and the maintenance period is the time to find and fix these errors.
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The purpose of BPR (business process redesign) is to improve business efficiency and reduce paperwork, thereby resulting in cost savings and increased quality and service. Unnecessary paperwork wastes time and resources. By streamlining workflows onto an electronic platform, activities such as ordering and billing can be made more efficient.
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The standards and protocols enable seamless communication between the different applications and well-known examples include XML, SOAP, WSDL, and UDDI. XML (eXtensible Markup Language), SOAP(Simple Object Access Protocol), WSDL (Web Services Description Language), and UDDI (Universal Description, Discovery & Integration)are 4 very well known examples of standards and protocols.
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The term reengineering has been coined to describe the reworking and overhaul of information systems. Also known as business process redesign (BPR), reengineering usually applies to legacy systems which were put in place many years ago and are now obsolete and expensive to operate. Inevitably, this will have a domino effect on the rest of the system leading to a complete system redesign.
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The traditional SDLC approach is simply a methodology for developing an information system where the process is divided into formal steps that are taken in a particular sequence, with a rigid division of labor between end users and programmers. This is the definition of the traditional System Development Life Cycle(SDLC) approach.
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The traditional SDLC is also known as the waterfall approach because of the sequential order of activity. This term describes the one-way flow of activity in the traditional SDLC. One stage has to be completed to move on to the next stage.
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There are 3 main ways of applying BPR and these are reverse engineering, restructuring and reengineering. Simply put, reverse engineering means that the system is taken apart in order to determine how it works. The process will take into account the components and their interrelationships as well as the formation of documentation at a high level.
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There are 6 stages in the phased development approach. They are preliminary investigation, analysis, design, preliminary construction, final construction, and system test and installation. Investigation is a critical and extensive stage where developers, IT specialists, and users conduct an enterprise-wide review to discover the problem, work out possible solutions and objectives, assess thefeasibility of the project and obtain user feedback.
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There are many advantages to adopting web services including improving and automating business interactions between organizations, leasing ready-made software components from other organizations as required, and the reduction in the cost of systems integration since separate interfaces will no longer be needed. The cost of systems integration will be reduced by the use of the plug and play architecture.
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There are various approaches to conversion and these are the parallel strategy, pilot study, direct cutover and phased approach. The parallel strategy refers to the safe option where both the old and new systems are running at the same time until it is determined that the new system is acceptable. The main drawback to this form of new system implementation is that its expensive because the data has to be entered twice.
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Two critical aspects of introducing a new system are appropriate documentation and suitable training toensure that the system does not fail. Documentation is essential as a technical and user guide both during training and after implementation for reference purposes.
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System building is driven by end users; business priorities--rather than the technical preferences of the development team--are what ultimately count. The end-users will be the actual users of the system and their needs are based on business requirements. There is no point building a system that does not meet the business needs of a company.
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Systems analysts are experts at defining problems and in preparing documentation on how the computer will assist in solving these problems.
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The main activities in systems development are systems analysis, systems design, programming, testing, conversion, production and maintenance. Systems design supplies the specifications for the new information system and reveals how the technical and organizational elements fit together.
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The role of the system analyst in designing a system is to study the processes and procedures in place at the company to identify problems, propose one or more solutions, and then conduct the necessaryfeasibility studies taking into account the financial, technical and organizational impacts of those proposed solutions. The purpose of the feasibility study is to determine whether the problem can reasonably be solved with a computer system. In formal SDLC methodologies, the first step in systems analysis is a feasibility study.
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