Lecture1 NEW

7/29/2019 Lecture1 NEW

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System Analysis and Design

Dr. Aymen Zreikat

Mutah UniversityIT department

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Systems Analysis and Design

Topics

The Systems Development Life Cycle (SDLC)Planning

Analysis

Design

Implementation

Systems Development MethodologiesProject Team Skills and Roles


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The Systems Development Life Cycle

(SDLC)

The SDLC is composed of four fundamentalphases:

Planning

AnalysisDesign

ImplementationEach of the phases include a set of steps, which rely on

techniques that produce specific document files thatprovide understanding about the project.


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Phase I: Planning

This phase is the fundamental process of

understanding why an information system

should be built.

The Planning phase will also determine how the

project team will go about building the system.

The Planning phase is composed of twoplanning steps.


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Two Planning Steps

1. During project initiation, the systems

business value to the organization is identified

(How will it lower costs and/or increase

revenues?)

2. During project management, the project

manager creates a work plan, staffs the

project, and puts techniques in place to help

the project team control and direct the project

through the entire SDLC


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Phase II:Analysis

The analysis phase answers the questions of

who will use the system, what the system will

do, and where and when it will be used?

During this phase the project team investigates

any current system(s), identifies improvement

opportunities, and develops a concept for the

new system.

This phase has three analysis steps:


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Three Analysis Steps

1. Analysis strategy: This is developed to guide theprojects teams efforts. This includes an analysisof the current system.

2. Requirements gathering: The analysis of thisinformation leads to the development of a conceptfor a new system. This concept is used to build aset of analysis models.

3. System proposal: The proposal is presented tothe project sponsor and other key individuals whodecide whether the project should continue tomove forward


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Three Analysis Steps

The system proposal is the initial deliverable

that describes what business requirements the

new system should meet.

The deliverable from this phase is both an

analysis and a high-level initial design for the

new system.


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Phase III: Design

In this phases it is decided how the system will

operate, in terms of the hardware, software,

and network infrastructure; the user interface,

forms, and reports that will be used; and the

specific programs, databases, and files that will

be needed.


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Four Design Steps

1. Design Strategy: This clarifies whether the systemwill be developed by the company or outside the

company.

2. Architecture Design: This describes the hardware,software, and network infrastructure that will be used.

3. Database and File Specifications: These

documents define what and where the data will be

stored.

4. Program Design: Defines what programs need to be

written and what they will do.


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Phase IV: Implementation

During this phase, the system is either

developed or purchased (in the case of

packaged software).

This phase is usually the longest and most

expensive part of the process.

The phase has three steps.


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Three Implementation Steps

1. Installation: Prepare to support the installed

system.

2. System Construction: The system is builtand tested to make sure it performs as

designed.

3. Support Plan: Includes a post-implementationreview. PIR: is an assessment and review of thecompleted working solution. It will be performedafter a period of live running.

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Systems Development Methodologies

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Systems Development Methodologies

A methodology is generally a guideline for solving

a problem, with specific components such as

phases, tasks, methods, techniques and tools.

In this class, is a formalized approach to

implementing the SDLC.

The methodology will vary depending on whether

the emphasis is on businesses processes or onthe data that supports the business

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Process models

Here, the focus is on defining the activities

associated with the system: sell, buy,

register, etc.

representing the system concept as a set

of processes with information flowing into

and out of the processes.


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Data models

Here the focus is on defining the content of the

data storage and how they are organized:

customers, items, bells, etc.

representing the system concept as a set ofobjects (data items) using some processes togovern the relations between these objects.
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Waterfall Development-based Methodology


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Waterfall Development

With waterfall development- basedmethodologies, the analysts and users proceedsequentially from one phase to the next.

The two key advantages of waterfalldevelopment-based methodologies are:

- The system requirements are identified long

before programming begins.- Changes to the requirements are minimized asthe project proceeds.


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Waterfall Development

The two key disadvantages of waterfall

development-based methodologies are:

- The design must be completely specified

before programming begins.- A long time elapses between the

completion of the system proposal in the

analysis phase and the delivery of the system.


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Parallel Development Methodology


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Parallel Development

This methodology attempts to address the long time

interval between the analysis phase and the delivery

of the system.


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Phased Development-based Methodology


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Phased Development

This methodology breaks the overall system into a

series of versions that are developed sequentially.

The team categorizes the requirements into a

series of versions, then the most important and

fundamental requirements are organized into the

first version of the system.

As each version is completed, the team beginswork on a new version.


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Prototyping-based Methodology


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Prototyping

Prototyping-based methodologies perform the

analysis, design and implementation phases

concurrently.

All three phases are performed repeatedly in a

cycle until the system is completed.

A prototype is a smaller version of the system

with a minimal amount of features.


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Prototyping

Advantage: Provides a system for the

users to interact with, even if it is not

initially ready for use.

Disadvantage: Users can get too involved

this results a low standard system and

perhaps legal problems.


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Throwaway Prototyping


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Throwaway Prototyping

Throwaway prototyping methodologies are

similar to prototyping based

methodologies.

The main difference is that the prototype is

not converted to the final product, it is only

used to assert the users requirements to

help the analysis and design phases.

Has relatively a detailed analysis phase.


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Agile Development Methodology


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Agile Development Methodology

This methodology uses extreme programming

Key principles of XP include:

Continuous testingSimple coding

Close interaction with the end users to build

systems very quickly


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Selecting the Appropriate Development

Methodology

Selecting a methodology is not simple, as no one

methodology is always the best.

Many organizations have their own standards.


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Selecting the Appropriate Development

Methodology

Some important methodology selection

criteria:

1. Clarity of User Requirements

2. Familiarity with Technology

3. System Complexity

4. System Reliability

5. Short Time Schedules

6. Schedule Visibility


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Clarity of User Requirements

Methodologies of prototyping, throwaway

prototyping and agile are usually more

appropriate when user requirements are

unclear as they allow users to interact

early in the SDLC.


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Familiarity with Technology

If the system is designed without some

familiarity with the base technology, risks

increase because the tools may not be

capable of doing what is needed.

Throwaway prototyping methodology

increase familiarity with the base

technology


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System Complexity

Complex systems require careful anddetailed analysis and design.

This can be provided by Throwaway

prototyping methodologies as the prototypecan be tested and the system re-analyzedand re-designed in details.


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System Reliability

System reliability is usually an important

factor in system development.

Throwaway prototyping methodologies are

most appropriate when system reliability is

a high priority.

Prototyping methodologies are generally

not a good choice as they lack careful

analysis and design phases.


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Short Time Schedules

Parallel and Phased methodologies are

well suited for projects with short time

schedules as they increase speed.

Waterfall methodologies are the worst

choice when time is essential as they do

not allow for easy schedule changes.


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Schedule Visibility

Prototyping and Phased methodologies

move many of the critical design decisions

earlier in the project; consequently, this

helps project managers recognize and

address risk factors and keep expectations

high.

C it i f S l ti M th d l


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Criteria for Selecting a Methodology

Ability to

develop systems

waterfall parallel phased Prototype Throwaway

prototyping

Agile

Unclear user

requirements

poor poor good exclnt exclnt exclnt

Unfamiliar

technology

poor poor good poor exclnt poor

That one complex good good good poor exclnt poor

That one reliable good good good poor exclnt good

With Short time poor good exclnt exclnt good exclnt

With schedule

visibility

poor poor exclnt exclnt good good


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Project Team Skills and Roles


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Projects should consist of a variety of skilledindividuals in order for a system to besuccessful.

five major skill sets an analyst should haveinclude:Technical

Business

AnalyticalInterpersonal

Management


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TechnicalMust understand how computer, database,

operating system and network works

Must have enough experience with computercapabilities (H/W & S/W)

Should be familiar with

Programming language

Operating system

Database

System development tools CASE and CAD tools


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Business

Identify the key business aspects of the system

Identify how the system will provide business value

Analytical

System thinking

Components, boundaries, environment, input,

output, interface, purpose, sub-system


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Interpersonal

Communication skills

Ability to communicate clearly and

effectively with others

Written form (reports)

Verbal form (phone, face to face)

Visual (presentation slides, diagrams)


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Management

Resource management

Project managementChange management


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Categories of Analysts

Business Analyst

Systems Analyst

Infrastructure Analyst

Change Management Analyst

Project Manager


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