[III] GROUP BASED APPROACHES
Information system design is defined as those tasks that focuses on the specification of a detailed computer based solution. It is also called physical design. Thus, whereas system analysis emphasized the business problem, systems design focusses on the technical or implementation concerns of the system.
There are many strategies or techniques performing system design. They include modern structured design, information engineering, prototyping, JAD, RAD and object-oriented design that streamline and improve the system analysis and design process.
Prototyping Traditionally, physical design has been a paper and pencil process. Analysts drew pictures that depicted the layout or structure of outputs, inputs or databases and the flow of dialogue and procedures. This is a time consuming process that is prove to considerable errors and emissions.
Today, many analysts prefer prototyping, a modern engineering-based approach to design. The prototyping is an interactive process involving a close working relationship between the designers and users. This approach has several advantages :
- Prototyping encourages and requires active end-user participation. This increases end-user morale and support for the project.
- Prototypes are an active model that end users can see, touch, feel and experience.
- Prototyping can increase creativity because it allows for quicker user feedback, which can lead to better solutions.
- An approved prototype is a working equivalent to a paper design specification, with one expectation e., errors can be detected much earlier.
Prototyping is often used in system development to clarify user requirements in imprecise systems. A decision to user prototyping is usually made in the feasibility phase.
Prototyping is used to gain a better understanding of possible solutions and the prototype then becomes a requirements model in the system specification phase. The dotted line indicates that some parts of the prototype may eventually become parts of the new system.
Ideally, the prototype serves as a mechanism for identifying software requirements. If a working prototype is built, the developer attempts to use existing program fragments or applies tools that enables working programs to be generated quickly.
RAD (Rapid Application Development) Model The RAD (Rapid Application Development Model) is proposed when requirements and solutions can be modularized as independent system, each of which. can be developed by different teams. After these smaller system components are developed, they are integrated to produce the large software system solution. The modularization could be on a functional, technology, or architectural basis, such as end-back-end, client side-sever side and so on.
RAD becomes faster if the software engineer uses components technology such that the components are really available for reuse. Since the development is distributed into component development teams, the teams work in tandem and total development is completed in a short period (i.e., 60 to 90 days) figure below shows the RAD Model :
1. Business Modeling : It covers the following functions :
- Where does information come from and go ?
- Who processes it ?
- What information driven the business process ?
- What information is generated ?
2. Data Modeling : The information flow defined as part of the business-modeling phase is refined into a set of data objects that are needed to support to business. The characteristics of each object are identified and the relationships between these objects are defined.
3. Process Modeling : In this model, information flows from object to object to implement a business function. To add, modify delete or retain a data object, there is a need of description which is done in this phase.
4. Application Generation : RAD assumes the user of fourth generation techniques, the RAD process works to sense existing program components or create reusable components. To facilitate the construction of the software using above cases, automated tools are used.
5. Testing and Turnover : In this phase, the programs are tested, but some already existing programs which are already tested are used due to which the time involved in testing is less. Only the new program or components must be tested.
RAD process enables a development team to create ‘fully functionally system’ within very short time period.
Joint Application Development(JAD)
In the late 1970s, the system development personnel at IBM developed a new process for collecting information system requirements and reviewing system designs. The process is called JAD (Joint Application Design). The idea behind JAD is to structure the requirements determination phase of analysis and the reviews that occur as the part of design. Users, managers and system developers and brought together– for a series of intensive structured meetings run by a JAD session leader. By gathering the people directly affected by an IS in one room at the same time to work together to agree on system requirements and design details, time and oragnizational resources are better managed. Group members are more likely to develop a shared understanding of what the Information system is supposed to do. JAD has become common in certain industries such as insurance and in specific companies such as CIGNA.
Following is the list of typical JAD participants :
- JAD session leader – Organizes and runs the JAD.
- Users – The key users of the system.
- Sponders – Due to its expense, a JAD must be sponsored by someone at relatively high level in the company.
- System Analysts.
- Scribe – Scribe takes notes during JAD sessions usually on PC or laptop.
- IS Staff – such as programmers, database analysts, data center personnel may attend the session. Their purpose is to learn from the discussions and possible td contribute their ideas on the technical feasibility of proposed ideas or on theytechnical limitations of current systems.
Joint Application Development (JAD) is a popular fact-finding technique that brings users into the development process as active participants.
The JAD process is based on four simple ideas :
- People who actually do a job have the best understanding of that job.
- People who are trained in information technology have the best understanding of the possibilities of that technology.
- Information systems and business processes rarely exist in isolation — they transcend the confines of any single system or office and affect work in related
departments. People working in these related areas have valuable insight on the role of a system within a larger community.
- The best information systems are designed when all of these groups work together on a project as equal partners.
Typical Session Agenda
Project leader :
- Introduce all JAD team members
- Discuss ground rules, goals, and objectives for the JAD sessions
- Explain methods of documentation and use of CASE tools, if any Top management (sometimes called the project owner or sponsor) : Explain the reason for the project and express top management authorization and support.
Project Leader :
- Provide overview of the current system and proposed project scope and constraints.
- Present outline of specific topics and issues to be investigated.
Open discussion session, moderated by project leader :
- Review the main business processes, tasks, user roles, input, and output
- Identify specific areas of agreement or disagreement
- Break team into smaller groups to study specific issues and assign group leaders.
JAD team members working in smaller group sessions, supported by IT staff:
- Discuss and document all system requirements
- Develop models and prototypes.
Group leaders :
- Report on results and assigned tasks and topics
- Present issues that should be addressed by the overall JAD team
Open discussion session, moderated project leader :
- Review reports from small group sessions
- Reach consensus on main issues
- Document all topics
Project leader :
- Present overall recap of JAD session
- Prepare report that will be sent to JAD team members
Advantages and disadvantages
Compared with traditional methods, JAD may seem more expensive and can be cumbersome if the group is too large relative to the size of the project. Many companies find, however, that JAD allows key users to participate effectively in the requirements modeling process. When users participate in the systems development process, they are more likely to feel a sense of ownership in the results, and support for the new system. When properly used, JAD can result in a more accurate statement of system requirements, a better understanding of common goals, and a stronger commitment to the success of the new system.
A drawback of JAD is that it opens up a lot of scope for inter-personal conflict.