System Engineering(part 2)

System Modelling

During the system requirements and design activity, systems may be modelled as a set of components and relationships between these components. These are normally illustrated graphically in a system architecture model that gives the reader/user an overview of the system organization. So, system modelling is an architectural model presents an abstract view of the sub-systems making up a system. It may include major information flows between sub-systems. It usually presented as a block diagram showing the major sub-systems and interconnections between these subsystems and identify different types of functional component in the model.

For example: intruder alarm system

In a given figure, component types in alarm system are:

Movement sensor:Detects movement in the rooms monitored by the system

Door sensor:detects door opening in the external doors of the building

Alarm controller:Controls the operation of the system

Siren:Emits an audible warning when an intruder is suspected

Voice synthesizer:Synthesises a voice message giving the location of the suspected intruder

Telephone caller:makes external calls to notify security, the police, etc

Classes of Information System

a.Transaction processing system:Transaction processing systems are information system applications that capture and process data
about business transactions.

b.Management information system:A management information system (MIS) is an information system application that provides for
management-oriented reporting. These reports are usually generated on a predetermined schedule
and appear in a prearranged format.

c.Decision support system:A decision support system (DSS) is an information system application that provides its users with decision-oriented information whenever a decision-making situation arises. When applied to executive managers, these systems are sometimes called executive information systems (EIS).

d.Expert system:An expert system is a programmed decision-making information system that captures and reproduces the knowledge and expertise of an expert problem solver or decision maker and then simulates the “thinking” or “actions” of that expert.

e.Office automation system:Office automation (OA) systems support the wide range of business office activities that provide for improved work flow and communications between workers, regardless of whether or not those workers are located in the same office.

System Analyst

A systems analyst studies the problems and needs of an organization to determine how people, data, processes, communications, and information technology can best accomplish improvements for the business. When information technology is used, the analyst is responsible for:

• The efficient capture of data from its business source,
• The flow of that data to the computer,
• The processing and storage of that data by the computer, and
• The flow of useful and timely information back to the business and its people.

Task of System Analyst:

1. Identify the problem
2. Analyze and understand the problem
3. Identify solution requirements or expectations
4. Identify alternative solutions and decide a course of action
5. Design and implement the “best” solution
6. Evaluate the results. If the problem is not solved, return to step 1 or 2 as appropriate

Attributes of System Analyst:

1. Working Knowledge of Information Technology
2. Computer Programming Experience and Expertise
3. General Business Knowledge
4. Problem-Solving Skills
5. Communications Skills
6. Interpersonal Relations Skills
7. Flexibility and Adaptability
8. Character and Ethics

Reference:

• Sommerville, Ian. Software engineering. eight edition. Newyork: pearson, 2007.
• coursehero. <https://www.coursehero.com/file/11487611/Chapter1-Introduction-to-Software-Engineering-cs/>.
• software engineering<https://books.google.com.np/books?id=CDWRq0B9e5kC&pg=PA5&lpg=PA5&dq=+Software+Software+is+computer+programs+and+associated+documentation.&source=bl&ots=fuFOT7wYOS&sig=0tkbWoER8gf7RxbScRjIQc7W_d0&hl=en&sa=X&redir_esc=y#v=onepage&q=Software Software is%>.
• csitprogram. .