System Analysis and Design Short Questions

 

               

Use case Modeling:       Describes what a system does without describing how the system does

=>  A logical model of the system

=> Use case is a view of the system requirements

       =>  Analyst works with business experts to develop requirements

           =>Communication between the business team and the development team

       => works into behaviors, services, and responses (the use cases) that are significant to the    users of the system.

 Interrelatedness & Interdependency: All systems and subsystems are interrelated and interdependent. All systems process inputs from their environments.

Interrelatedness: Student to Admission, Student to Library

Interdependency: Student is dependent on Admission or Registry but not dependent on Library. Accounts section depends on Admission and vice versa.

Openness: Information is open for all. Example: Admission information

Closedness: Information is restricted. Example: Financial Statements of University

Virtual Organization: Virtual organization is a temporary or permanent collection of geographically dispensed individuals, group or organizational unit.

Virtual Team: A team that is formed virtually and communicating virtually.

Enterprise Resource Planning (ERP): It refers to a type of software that organizations use to manage day-to-day business activities such as accounting, procurement, project management, risk management and compliance, and supply chain operations.

Three Depicting Systems Graphically:

1. Context-level data flow diagrams - Focuses on the data flowing into and out of the system and the processing of the data

2. Entity-relationship model - Focus is on the entities and their relationships within the organizational system

3. Use case modeling - Logical model of the system. Describes what a system does without describing how the system does. Example: Examination, Vision Processing, Course Offering in the Use Case.

*Relationships show how the entities are connected. Three types of relationships: One-to-one, One-to-many, Many-to-many

#Use Case Diagram:

   Types of actor:

Actor: Refers to a particular role of a user of the system.

Primary Actor: Real source & destination of data.

Supporting Actor: who will help the primary actor. 

Use case symbols: An oval indicating the task of the use case

Connecting lines: Arrows and lines used to diagram behavioral relationships

#Use Case Provides Three Things:

-Actor starts an activity

-Activity goes to use case

-Use case performs the action

 types of behavioral relations:

1. Communicates: Used to connect an actor to a use case. Symbol is straight line. Example: Student appearing in exam.

2. Includes: Doing one work completes all other ones. Symbol is Insider dashed arrow. Example: Semester fee completes other fees.

3. Extends: Doing the perquisite thing. Symbol is Outside dashed arrow. Example: Complete SSC then you can give HSC.

4. Generalizes: Having different actors but their job is same. Symbol is Outside straight arrow. Example: Part Time & Full Time Teachers.

Developing Use Case Diagrams:

-Review the business specifications and identify the actors involved

-May use agile stories

-Identify the high-level events and develop the primary use cases that describe those events and how the actors initiate them

-Review each primary use case to determine the possible variations of flow through the use case

-The context-level data flow diagram could act as a starting point for creating a use case

Why Use Case Diagram is useful:

-Identify all the actors in the problem domain

-Actions that need to be completed are also clearly shown on the use case diagram

-The use case scenario is also worthwhile

-Simplicity and lack of technical detail

Level of management shows who are the people working in the office.

                                              Three levels:

Operational Control: People has to follow the rules. Example: IUBAT students.

Managerial Planning & Control: People has to follow the rules but in some cases they can take some short term decisions which may be out of the rules. Example: IUBAT faculties.

Strategic Management: Who develops the rules for mid-level & bottom level. Example: IUBAT Authorities.

Organizational Culture: How an organization will work. Verbal & Nonverbal Symbolism.

Assembling a team: Shared value of teamwork, Good work ethic, Honesty, Competency, Taking Leadership, Motivation, Trust of teammates

8.Project Management Fundamentals:

-Project initiation: Identifying problems & opportunities for improvement

-Project feasibility: Probability & Suitability

-Activity planning and control: Estimating time, Scheduling the project, Compare the plan, Take appropriate action

-Project scheduling

-Managing systems analysis team members

Identifying Problems:

-Checking output on performance: Too many errors, Work Completely slowly, Work done incorrectly, Work done incompletely, Work not done at all

-Observe behavior of employees: High absenteeism, High job dissatisfaction, High job turnover

-Listening to external feedback(vendor, customer, supplier): Complaints, Loss of sales, Lower sales,

 Suggestions for improvement:

 

Problem Definition:

-Problem statement: what are the problems

-Issues: Things occur due to that problem

-Objectives: How to solve the problem

-Requirements: Process of solving the problem

Selection of the project:

-Backing from management

-Appropriate timing of project commitment

-Possibility of improving achievement of organizational goals

-Practical in terms of resources for the system analyst and organization

-Worthwhile project compared with other ways the organization could invest resources

Determining Feasibility:

Technical Feasibility:

-Improve present system

-Technology available to meet users' needs

Economic Feasibility:

-Systems analysts' time

-Cost of systems study & employees' time for study

-Estimated cost of hardware

-Cost of packaged software or software development

Operational Feasibility:

-Whether the system will operate when put in service

-Whether the system will be used

Estimating Workloads: Systems analysts formulate numbers that represent both current and projected workloads for the system so that any hardware obtained will possess the capability to handle current and future workloads

Ascertaining Hardware & Software Needs:

-Inventory computer hardware currently available

-Estimate current and future system workloads

-Evaluate available hardware and software (New Hardware/Cloud Service, Own Software/COTS Software/SaaS Provider)

-Choose the vendor (Hardware vendor/Cloud Service Provider, Design & Develop In-house/Choose Software Product & Manufacturer/Saas Provider)

-Acquire the computer equipment

COTS(Commercial off the Shelf) - Buying the software or programming language and develop the software.

SaaS (Software as a Service) - SaaS is a cloud-based method of providing software to users

 

Three Main Categories of Cloud Computing

àSoftware as a Service (SaaS)

àInfrastructure as a Service (IaaS)

àPlatform as a Service (PaaS)

Benefits of Cloud Computing:

-Less time spent maintaining legacy systems

-May be simpler to acquire IT services

-Scalable applications that can grow by adding more cloud resources

-Consistency across multiple platforms

-Capital is not tied up

Drawbacks of Cloud Computing:

-Loss of control of data stored in the cloud

-Potential security threats to data that is not stored on premises

-Reliability of the Internet as a platform

Identifying Benefits & Costs:

-Tangible benefit & cost can be measurable.

Example: Benefits: Access to otherwise inaccessible information, Access to information on a more timely basis

Costs: Cost of resources, Employee salaries

-Intangible benefit & cost cannot be measurable.

Example: Benefits: Maintaining a good business image, Increasing job satisfaction

Costs: Losing a competitive edge, Losing the reputation of being first

Comparing Costs & Benefits:

• Break-even analysis

•Payback

•Cash-flow analysis

•Present value analysis

Break-even Analysis: The point at which the total cost of the current system and the proposed system intersect

Cash-flow analysis: Cash-flow analysis is used to determine when a company will begin to make a profit and when it will be “out of the red.”

Payback analysis: The payback period is how long it will take to pay off the investment with the cash flow derived from the asset or project

Present value analysis:  which represents a stream of cash flow that has a negative (spend) component and a positive (income) component where either or both of these component vary over time, a present value analysis should be used to justify the project.

 

 

 

Work Breakdown Structure: A project needs to be broken down into smaller tasks or activities

Time Estimation Techniques:

-Relying on experience

-Using analogies

-Using three-point estimation

-Identifying function points

-Using time estimation software

Function Point Analysis:

Five Main Components:

-External inputs

-External outputs

-External queries

-Internal logical files

-External interface files

Project Scheduling:

Gantt Charts: Simple, Lends itself to end user communication, Drawn to scale

PERT diagrams: Useful when activities can be done in parallel

PERT Diagram Advantage:

-Easy identification of the order of precedence

-Easy identification of the critical path and thus critical activities

-Easy determination of slack time 

Estimating Cost:

-Estimate costs for each activity in the work breakdown structure

-Prepare a budget for the project and have it approved by the organization or client

Project Risk:

Project failures may be prevented by:

-Training

-Experience

-Learning why other projects have failed

Fishbone diagram systematically lists all of the possible problems that can occur