BUSİNESS INFORMATİON SYSTEMS

Change and Regulations: Need for information system renewal may be the result of changes in the laws and regulations instead of business demand or new technology.

The correct order of System development life cycle is as follows: Scope and Planning, Requirements Analysis, Design, Realization and Test, Setup and Disribution, Operation and Maintenance.

Scheduling feasibility: Is it possible to set up the proposed system in the determined time interval? For this purpose, project activity scheduling techniques like PERT and Gantt charts are used to determine whether it is feasible to setup system on time.

Interviewing with the potential users is the best way to determine the system requirements. The users of the existing system and prospective users of the proposed system are the best information sources. Goals, informal procedures, feelings and opinions are important information obtained from interviews.

Advantages:

• Surveys can be answered very quickly.

• It is a relatively cheap data collection technique from many people.

• Surveys allow the respondents to be anonymous. Therefore, people may answer the question as they want rather than the answers that the employers wish.

• The answers could be quickly tabulated and analyzed.

Giving up the old system and starting the new system requires a careful planning and setup activity. Transition strategies are realized in four different ways depending on the degree of giving up the old system. These strategies are: parallel, pilot, phased, and direct.

Preventive maintenance: It is related to lengthening the service duration of the existing system, to reduce the likelihood of future system failures. Although this type of maintenance has the lowest priority, it adds high value to the organization.

The spiral model is an evolutionary model that allows the iterative structure of the Prototyping to be controlled by a systematic approach of the Linear Sequential Model. It enables rapid development of incremental versions of the system software.

Analyst tools; they help automatically find missing or incorrect features in the diagrams, display, and reporting.

In the first phase of System Development Life Cycle, scope, opportunities and goals of the problem represented by the information system project are determined. The success of the rest of the project depends on the correct definition of the problem. In the scope of the problem; size, borders, vision, constraints, limits, stakeholders, budget and timing of the project are determined.

In the first phase of System Development Life Cycle, scope, opportunities and goals of the problem represented by the information system project are determined. The success of the rest of the project depends on the correct definition of the problem. In the scope of the problem; size, borders, vision, constraints, limits, stakeholders, budget and timing of the project are determined. It includes cost control and budget management and resource allocation.

The purpose of the feasibility study is to investigate likelihood of the system development project. At the end of the feasibility study, project plan and estimated budget of the project are obtained. During the feasibility study, generally, a pre-investigation is conducted on the system. At this stage, considering the sources and constraints of the business, it is decided whether or not it is feasible to solve the problem.

After completing the plan and determining the starting and finishing times of the activities that compose the information system development project, system requirements are analyzed. These requirements can be classified into three groups: functional requirements, nonfunctional requirements, and environment requirements.

To determine the functional requirements, the following questions are asked:

Using these type of questions, the requirements describing the system function in detail are determined and prioritized. Besides this, the analyst uses the questions and answers related to human- computer interaction and work environment of the system.

After completing the plan and determining the starting and finishing times of the activities that compose the information system development project, system requirements are analyzed. These requirements can be classified into three groups: functional requirements, nonfunctional requirements, and environment requirements.

Pilot: In this strategy, the new system is operated in only a branch or department. As the pilot operation is completed or starts to operate correctly, transition is applied to the other parts of the business synchronously or gradually. In pilot transition, the old system is kept but not activated.

The Spiral model, which consists of 4 phases;  

Determine Objectives and Constraints: An effective communication between the developer and the customer is established and tasks to define resources, timelines and other information related to the project are performed.

Risk Analysis: Technical and management risks are determined and Risk mitigation plan is prepared.

Engineering: One or more solutions for the application are developed. The tasks of designing and building the system, creating test, installation and user support (documentation, user training) are executed.

Evaluation: Customers evaluate the application and provide their feedback to the system. The next phase of the system is planned and the changes are incorporated.

Application development environments (ADE) have been replaced by the use of program compilers due to the demand for rapid and quality software development. With these application development environments, programs can be developed more simply and efficiently.

User Interface (UI) Design software: It allows programmers to create fast interfaces through component libraries.

Network connectivity and Database middleware software: It allows programmers to integrate the software they develop into different databases and into their network quickly.

Testing tools: They provide the testing of the developed software with test scenarios.

Version control software: It allows programmers working as team to manage, store and access different versions of the software (source and running software) that is developed and installed after development.

Help Authoring tools: They are used for writing online help, online training, and user manuals.