Chapter 5

System AnalysisSarah El Sehemawy

Karim ElsabeeSherine MeshadHakim Meshriky

Ahmed Zaki Ismail Abou Hamda

System Analysis System Analysis

It is a problem solving technique that decomposes a system into component pieces for the purpose of studying how well those components work and interact to accomplish their purpose.

It primarily focuses on the business view, independent of any technology.

System Design It is a complementary problem solving

technique to system analysis that reassembles a system’s components pieces back into a complete system – hopefully an improved system. This may involve adding, deleting and changing pieces relative to the original system.

System Analysis Approaches

Model-Driven Analysis Approaches Structured Analysis Information Engineering Object-Oriented Analysis

Accelerated Analysis Approaches Discovery Prototyping Reverse Engineering

Model-Driven Analysis Approach

Structured Analysis Definition: It is a model-Driven, Process-centered technique used to

analyze an existing system, and propose a new one. Processes are the primary focus of that system model. Data and interface are also modeled.

Output: Process models called Data Flow Diagrams (DFDs) Information Engineering (IE)

Definition: Also model-Driven, but Data-centered. It intends to synchronize the system’s data, and then processes. It is data centered because it focuses on the data requirements of the system.

Output: Data model called Entity Relationship Diagram (ERD). The two previous approaches differ only in the order of drawing the

DFD, and the ERD. Object-Oriented Analysis (OOA)

Definition: It is a model-driven technique that integrates Data and Processes concerns into constructs called Objects. OOA modes are pictures that illustrate the system’s objects.

Output: Unified Modeling Language (UML) depicts the OOA models. Difference: No Database. Data and Processes are stored physically on

the same layer.

Accelerated Analysis Approaches Definition: Accelerated approaches emphasize

the construction of prototypes to more rapidly identify the business and user requirements for a new system.

Prototype: Small-Scale, incomplete, but working sample of a desired system.

Types: Discovery Prototyping: Identifies user’s business

requirements by having to react to a quick implementation.

Reverse Engineering: Reads the program code for an existing database, program, and automatically generates system model, which is edited, and improved.

Project Phases Preliminary Investigation Phase Problem Analysis Phase Requirement Analysis Phase Decision Analysis Phase Design Phase Construction Phase Implementation Phase Operation and Support Phase

Preliminary Investigation – Phase 1

The Preliminary Investigation phase First phase of the classic systems development

process. Answers the question: “Is the project worth

looking at?”. It is intended to be quick & should not

exceed 2 or 3days for most projects. Most of the tasks in this phase are led by a

senior systems analyst or a project manager and include system owners as participants.

Phase 1 - Preliminary Investigation Con’t

1. List problems ,opportunities and directives

2. Negotiate preliminary scope3. Assess project worth4. Plan the project5. Present the project and plan

Preliminary Investigation Consists of the following 5 steps:

Phase 1 - Preliminary Investigation Con’t

1. List problems, opportunities and directives:

Each problem, opportunity or directive is assessed with respect to urgency, visibility, benefits and priority.

The key deliverable of this task is a preliminary problem statement.

Primary techniques include fact-finding & meeting with system owners.

Phase 1 - Preliminary Investigation Con’t

2. Negotiate preliminary scope: Scope defines the boundary of the project. A project’s scope can be described in terms of:

What types of data describe the system being studied?

What business processes are included in the system being studied?

How must the system interface with users, locations and other systems?

This task deliverable is the preliminary problem statement with scope.

Primary techniques to accomplish this task are also fact-finding &meetings.

3. Assess project worthThis is where we answer the question: “ Will the development of the new

system return enough value to offset the costs incurred?”

There is no physical deliverable than the go or no-go decision.

The remaining tasks are necessary only if the project is approved.

Phase 1 - Preliminary Investigation Con’t

4. Plan the project: An initial project plan should consist of

at least the following: A preliminary master plan that includes

schedule and resource assignments for the entire project.

A detailed plan and schedule for completing the next phase of the project.

The deliverable of this task is the project plan.

Phase 1 - Preliminary Investigation Con’t

5. Present the project and plan: Unless the project is predetermined to be of the highest

priority, it must be presented to a steering body for approval.

A steering body is a committee of executive business and system managers that studies and prioritize project proposals to determine which projects should be approved or continued.

Deliverable of this task is the project charter, which is usually a document.

The project charter defines the project in terms of participants, problems, opportunities and directives; methodology; statement of work to be completed; deliverables; quality standards and budget.

If approved, the project can now proceed to the problem analysis phase.

Phase 1 - Preliminary Investigation Con’t

Phase 2 : Problem Analysis Phase

Answers the questions :

Goal:

“ Don’t try to fix it , unless you understand it!”

Final Deliverables :

  Are the problems really worth solving?  Is a new system really worth building?

Study and understand the problem domain well enough to thoroughly analyze its problems, opportunities and constraints.

Produce System Improvement Objectives that address problems , opportunities and directives

The Problem Analysis Phase (6 Steps)

Learn about the current system in which the bus problems opportunities, directives and constraints exist.

Learn to truly analyze a problem before stating any possible solutions

Analyze each perceived problem for cause and effect

Appropriate only to business process redesign

examine business process to measure value added or subtracted by each process as it relates to the total

organization

Analyze Problems and Opportunities

    Study the problem domain

Analyze Business Processes (Optional)

The Problem Analysis Phase (6 Steps)

Establish System Improvement Objectives

Establish the criteria against which any improvement to the system will be measured and identifies any constraints that may limit flexibility in achieving these improvements. Update The Project Plan Reevaluating scope and update the project plan accordinglyPresent findings and recommendations Appropriate elements are combined into system improvement objectives , presented in a report or a verbal presentation

Conclusion:

Continue , adjust or cancel the project

Phase 3:Requirement Analysis

Phase

This phase defines the Business Requirements for a new system

What do the users need and want from a new system? WHAT NOT

HOW!

The Requirement Analysis Phase includes the following tasks:

1- Define Requirements 2- Analyze Functional Requirements

3- Trace and Complete Requirements 4- Prioritize Requirements

5- Update the Project Plan

Define Requirements:

This task translate the system improvements objectives (established in the problem analysis phase) into an outline of Functional and Nonfunctional requirements that will be needed to meet the objectives

Analyze Functional Requirements:

Functional Requirements are analyzed such that they can be verified and communicated to both:

Users so they can prioritize the needs and justify the expenses Designers so they can transform them into appropriate technical

solutions. There are 2 approaches to functional requirements documentation and

validation SYSTEM MODELING & PROTOTYPING. Requirements are analyzed for accuracy, urgency, consistency,

flexibility and feasibility.

Trace and Complete Requirements:

Tracing each system model and/or prototype back to the functional requirement that it fulfills and ensuring that all functional requirements are included in the system models or prototype.

Phase 3:Requirement Analysis

Phase

Prioritize Requirements:

System Owners and Users should prioritize business because it may be useful to recognize which requirements are more important than others if a project gets behind schedule or over budget.

Prioritization of business requirements enable TIMEBOXING, which is a technique that delivers system functionality and requirements through versioning.

All MANDATORY REQURMENTS are included in Version 1.0 (the System is useless without it)

All DESIRABLE REQUIRMENTS are included following version according to there ranking.

Update the Project Plan:

Scope Schedule Budget Output of this phase is a business requirements statement.

Phase 3:Requirement Analysis

Phase

Project Phase 4:

Decision Analysis Phase

DECISION ANALYSIS

PHASE

Business requirements

System Proposal

Project Phase 4:

Decision Analysis Phase

The decision analysis phase includes 5 tasks as follows

1. Identify Candidate Solutions(Sources :System Owners, Users, analysists , Desginers, technical consultants……)

2. Analyze Candidate Solution (Feasibility)

Operational Economic Schedule Technical (done by system designers and builders)

Project Phase 4:

Decision Analysis Phase

3. Compare Candidate Solutions (Feasibility analysis Matrix)

Feasibility criteria Weight Candidate1

Candidate2

Candidate3

1.Operational

2.Technical

3.Economic

4.Schedule

Ranking 100% % % %

Project Phase 4:

Decision Analysis Phase

4. Update the project plan

5. Recommend a solution

Cross Life Cycle Activities Cross life cycle activities are activities that overlap many

or all phases of the methodology.

Fact Finding Formal process of using research, interviews,

meetings, questionnaires, sampling. Also Called data collection.

Documentation and Presentations Activity of recording facts and specifications

for a system for current and future reference. Communicating Findings, recommendations,

and documentation for review by interested managers

Cross Life Cycle Activities

Feasibility Analysis Continuous Analysis of the

development of the IS. Project Management

Defining, planning, directing, monitoring, and controlling a project to develop an acceptable system within the specified time, and budget.