1. Explain class stereotypes; include the boundary class, entity class and control class
A boundary class is a class used to model interaction between the system's surroundings and its inner workings. Boundary classes model the parts of the system that depend on its surroundings. Boundary classes also make it easier to understand the system because they clarify the system's boundaries. They aid design by providing a good point of departure for identifying related services
A control class is a class used to model control behavior specific to one or a few use cases. Control objects (instances of control classes) often control other objects, so their behavior is of the coordinating ...view middle of the document...
The five main approaches for determining systems requirements are background reading, interviewing, observation, document sampling and questionnaires. Aim of background reading is to understand the organization and its business objectives. It includes reports, organization charts, policy manuals, job descriptions and documentation of existing systems. The advantage of background reading is helps to understand the organization before meeting the people who work there. Besides that, it helps to prepare for other types of fact finding and documentation of existing system may help to identify requirements for functionality of new system. The disadvantage of background reading is written documents may be out of date or not match the way the organization really operates.
Second approach is by using interviewing. The aim of interview is to get an in-depth understanding of the organization’s objectives, users’ requirements and people’s roles. It includes managers to understand objectives, staff to understand roles and information needs and customers and the public as potential users. The advantages are personal contact allows the interviewer to respond adaptively to what is said. In addition, it is possible to probe in greater depth and if the interviewee has little or nothing to say, the interview can be terminated. The disadvantage is can be time-consuming and costly. Moreover, notes must be written up or tapes transcribed after the interview and can be subject to bias. In addition, if interviewees provide conflicting information this can be difficult to resolve later
Third approach is observation. Aim is to see what really happens, not what people say happens. It includes seeing how people carry out processes, seeing what happens to documents, obtaining quantitative data as baseline for improvements provided by new system and following a process through end-to-end. The observation can be open-ended or based on a schedule. The advantages of observation is first-hand experience of how the system operates, high level of validity of the data can be achieved, verifies information from other sources and allows the collection of baseline data. The disadvantages are people don’t like being observed and may behave differently, distorting the findings,requires training and skill, logistical problems for the analyst with staff who work shifts or travel long distances and ethical problems with personal data
Next approach is document sampling. The Aims of document sampling is to find out the information requirements that people have in the current system. It also aims to provide statistical data about volumes of transactions and patterns of activity. Basically, document sampling includes obtaining copies of empty and completed documents, counting numbers of forms filled in and lines on the forms and screenshots of existing computer systems. The advantages of document sampling is for finding out about error rates while the disadvantages of document sampling...