Requirements, Environment, and

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5 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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INFO425: System Design

INFORMATION SYSTEMS @ X

Chapter 8


Evaluating Alternatives for
Requirements, Environment, and
Implementation

Part 1

INFO425: System Design

INFORMATION SYSTEMS @ X

Objectives


Describe process for packaging/prioritizing system
requirements based on the desired system scope and
level of automation for the new system


Describe the strategic decisions that determine the target
deployment environment and the design approach for the
new system


Determine alternative approaches for system
development


Evaluate and select a development approach based on
the needs and resources of the organization



INFO425: System Design

INFORMATION SYSTEMS @ X

Overview


Last three activities of analysis


Prioritize systems requirements


Generate and evaluate alternatives


Review recommendation with management


Refocus project direction


Transition from discovery and analysis to solutions and
design


Set direction for design and implementation of solution
system

INFO425: System Design

INFORMATION SYSTEMS @ X

System Analysis Activities


Final three steps overlap with initial steps and done
iteratively


Steps:


Define priority of each event (function)


Define the level of automation for each event


Define the deployment environment (hardware, operating system,
network)


Identify design alternatives (e.g., custom development vs.
package)


Evaluate design alternatives


Select alternative and present to management


INFO425: System Design

INFORMATION SYSTEMS @ X

Project Management Perspective


Time


Cost


Quality


Human resources


Procurement


Communications


Risk


The final activities of the Systems Analysis phase are
largely (but not entirely) project management activities


Overall goal is to precisely define scope and to specify
how system will be implemented. This allows the project
manager to quantify the following dimensions of the
project:

INFO425: System Design

INFORMATION SYSTEMS @ X

Deciding on Scope and Level of Automation


Scope determines which business functions (events) will
be included in system


Level of automation is how much automated computer
support exists for functions included in scope


Aim is to precisely define functions in scope and level of
automation for each function to avoid
scope creep


Requests for addition of system functions after requirements have been defined
and decision has been made


To avoid, formalize the process


Get key stakeholders to participate and sign off

INFO425: System Design

INFORMATION SYSTEMS @ X

Prioritizing Requirements


Assume that Event = Function


Use an expanded Event Table


Typically, priority is defined when Event table is built, then
refined


Priority: Mandatory, Important, Desirable


Level of Automation

Event/Function

Priority

Low

Medium

High

Schedule a course section

Mandatory

Enroll in Course

Mandatory

Provide student
suggested curriculum for
upcoming academic year

Desirable

Generate student
timetable

Important

INFO425: System Design

INFORMATION SYSTEMS @ X

Defining Level of Automation


High

>
System takes over processing of business function … does most of the
work …. Applies business logic / rules

>
Ask the question: how should this function be done ideally


Medium

>
Midrange point which combines features from low and high alternatives


Low

>
Simple computer records keeping

>
Often involves automating existing, manual tasks

Level of Automation

Event/Function

Priority

Low

Medium

High

Provide student
suggested
curriculum for
upcoming academic
year

Desirable

Generate printout
based on
program, year
and courses
taken

Create tentative
schedule for year,
online, prompt student
to confirm/change as
required

Medium + generate
and email timetable
to student

INFO425: System Design

INFORMATION SYSTEMS @ X

RMO Customer Support System Functions

INFO425: System Design

INFORMATION SYSTEMS @ X

Exercise


Student Registration

Level of Automation

Event/Function

Priority

Low

Medium

High

Schedule a course
section

Mandatory

Enroll in Course

Mandatory

Generate student
timetable

Important

Define potential levels of automation for each function