ISOM221+Lecture+4+-+Requirement+Analysis+I

ISOM221+Lecture+4+-+Requirement+Analysis+I - ISOM221...

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ISOM221 Information Systems Analysis and Design Lecture 4: Requirement Analysis I 1 Systems Development Life Cycle Planning Analysis Design Implementation 2
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Agenda Understand how to create a requirements definition Become familiar with requirements analysis technique techniques Understand when to use each requirements analysis technique 3 The SDLC and Requirements The SDLC transforms the existing (as is) system into the proposed (to be) system The As-Is system is the current system and may or may not be computerized The To-Be system is the new system that is based on updated requirements Requirements determination step is the single most critical step of the entire SDLC Studies show that more than half of all system failures are due to problems with requirements 4
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Key Ideas The goal of the analysis phase is to truly understand the requirements of the new system and develop a system that addresses them -- or decide a new system isn’t needed The System Proposal is presented to the approva The System Proposal is presented to the approval committee via a system walk-through Systems analysis incorporates initial systems design 5 Defining a Requirement A statement of what the system must do or what characteristic it must have During analysis, requirements are written from the perspective of the businessperson Two kinds of requirements: Functional Nonfunctional 6
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Functional Requirements A process the system has to perform (e.g., search for available inventory) Information the system must contain (e.g., budgeted and actual expenses) Requirement Types Nonfunctional Requirements Behavioral properties the system must have Operational – the physical and technical environments in which the system will operate Performance – the speed, capacity, and reliability of the system Security – who has authorized access to the system under what circumstances Cultural and political – cultural, political factors and legal requirements that affect the system 7 Nonfunctional Requirements Requirement type Example Operational The system should be able to fit in a pocket or purse The system should be able to integrate with the existing inventory system Performance Any interaction between the user and the system should not exceed 2 seconds The system should receive updated inventory information every 15 minutes Security Only direct managers can see personnel records of staff Customers can see their order history only during business hours The system should be able to distinguish between United
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This note was uploaded on 12/22/2010 for the course ISOM ISOM221 taught by Professor Sheunhhee during the Spring '09 term at HKUST.

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ISOM221+Lecture+4+-+Requirement+Analysis+I - ISOM221...

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