PTI444.07 - Requirement Analysis

7/29/2019 PTI444.07 - Requirement Analysis

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Didik Dwi P

[email protected]

Requirement Analysis


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Bahasan

Requirement engineeringRequirement analysis

Fact-finding techniques

Business Requirement Specification (BRS)


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System Analysis Phase Overview

System analysis phase tasks:Requirements

Process Modeling

Data ModelingTransition to Systems Design


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What are requirements?

Functional expectationsPerformance expectations

Constraints

System (existing, legacy)Environmental

Cultural

etc


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Requirement Engineering


Requirement AnalysisRequirement Determination +

Basis for discussions withcustomer

Design basis for developers


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Requirement Engineering covers all of the activitiesinvolved in discovering, documenting and maintaininga set of requirements for a computer-based system(Sommerville)

Requirements engineering is an activity that involvescapturing, structuring and accurately representing theclients requirements in a manner that can beeffectively implemented in a system that will conform to

the clients specifications (Sawyer)


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Why requirement engineering is important?In software development projects, the RequirementsEngineering Process (REP) can influence thedevelopment:

Cost

Time

Effort

Quality

Major causes of project failures:

Incomplete requirements

Changing requirements


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Requirement analysis

Other names:Definition phase

Input:

System improvement objectives

Project charter

Output:

Business Requirement Statement (BRS)

Most techniques usedFact-finding


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A system requirement is a characteristic or feature thatmust be included in an information system to satisfybusiness requirements and be acceptable to users.

Inputs

OutputsProcesses

Performance

Controls


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Functional requirement: something the informationsystem must do

Print invoice, read employee records, etc

Nonfunctional requirement: a property or quality the

system must haveCost

Performance

Security

etc


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Criteria for System Requirements

Consistent not conflicting or ambiguous.Complete describe all possible system inputs andresponses.

Feasible can be satisfied based on the availableresources and constraints.

Required truly needed and fulfill the purpose of thesystem.

Accurate stated correctly.

Traceable directly map to functions and features ofsystem.

Verifiable defined so can be demonstrated duringtestin .


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Requirement example

The system must provide log-on security at theoperating system level and at the application level

Response time must not exceed four seconds

An employee record must be added, changed, ordeleted only by a member of the human resourcesdepartment

The system must support 50 users online

simultaneouslyThe transaction report should be generated every day at10 pm

The system must user-friendly to every type of users


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Fact-Finding Techniques

Fact-finding is the formal process of using research,interviews, sampling, questionnaires, and othertechniques to collect information about systems,requirements, and preferences

also known as information gathering or data collection


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Fact-Finding Techniques

Sampling of existing documentation, forms, anddatabases.

Research and site visits.

Observation of the work environment.

Questionnaires.

Interviews.

Prototyping.

Joint requirements planning (JRP).


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Sampling Existing Documentation

Sampling process of collecting a representativesample of documents, forms, and records.

Organization chart

Memos and other documents that describe the problem

Standard operating procedures for current system

Completed forms

Manual and computerized screens and reports

Samples of databases

Flowcharts and other system documentation

And more


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Research and site visits

ResearchComputer trade journals

Visit other companies with similar problems


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Observation

Observation a fact-finding technique wherein thesystems analyst either participates in or watches aperson perform activities to learn about the system.

Advantages

Data gathered can be very reliable

Disadvantages

People may perform differently when being observed


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Questionnaires

Questionnaire a special-purpose document that allowsthe analyst to collect information and opinions fromrespondents.

Advantages

Often can be answered quickly

Relatively inexpensive way to gather data from a largenumber

Disadvantages

No guarantee that an individual will answer all questions

Cannot observe body language


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Questionnaires

Multiple-choice questionsRating questions

Ranking questions

Rank the following transactions according to the amount of time you spend

processing them.

___ % new customer orders

___ % order cancellations

___ % order modifications

___ % payments

The implementation of quality discounts would

cause an increase in customer orders.

___ Strongly agree___ Agree

___ No opinion

___ Disagree

___ Strongly disagree

Is the current accounts receivable

report that you receive useful?

___ Yes

___ No


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Interview

Interview - a fact-finding technique whereby thesystems analysts collect information from individualsthrough face-to-face interaction.

Advantages

Give analyst opportunity to motivate interviewee torespond freely and openly

Can observe nonverbal communication

Disadvantages

Time-consuming

Success highly dependent on analyst's human relationsskills


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Prototyping

Discovery prototyping the act of building a small-scale, representative or working model of the usersrequirements in order to discover or verify thoserequirements.

Advantages:Can experiment to develop understanding of how system

might work

May minimize time spent on fact-finding

Disadvantages:Developers may need to be trained in prototyping

Could extend development schedule


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Joint Requirements Planning

Joint requirements planning (JRP) a process wherebyhighly structured group meetings are conducted for thepurpose of analyzing problems and definingrequirements.

Participant:Sponsor

Facilitator

Users and Managers

ScribesIT Staff


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Joint Requirements Planning

Joint requirements planning (JRP) a process wherebyhighly structured group meetings are conducted for the

purpose of analyzing problems and definingrequirements.

Participant:Sponsor

Facilitator

Users and Managers

ScribesIT Staff

PTI444.07 - Requirement Analysis

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