Lect1-System Analysis

8/7/2019 Lect1-System Analysis

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LECTURE 1

SYSTEM ANALYSIS

Stock Exchange = Pasar Modal


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IMPORTANT MESSAGES

1. QUESTIONS

Why Is your system running well?, why?

Your study You may not know, then check

What is your final academic performance?, IP


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Message Sejarah Pertanian

Berburu :Hasil 50 x lebih rendah dari menanam

Menanam: Hasil 1/50 dari industri

Pekerja Industri: Hasil 1/50 dari SmartBusinessmen (Entrepreneurs)


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IMPORTANT MESSAGES

Can your system be improved?, how?

1. Specify your system in term of input, output andprocess

2. Determine the main product of your system

3. Set the target to be achieved

4. Check the process of input to produce the mainproduct

5. Check the main input limiting the main product

6. Check other factors influencing the conversion ofinput to the main product

7. Draw a diagram connecting input, output and other

factors


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2. SYSTEM IMPROVEMENT

Planning Why build the system? How should you (the team) go about building it?

Analysis Who uses system,

what will it do, where and when will the system be used?

Design How will the system work?

Implementation System delivery


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3. DATA FLOW DIAGRAMS (DFD)


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LECTURE FLOW

INTRODUCTIONA. DEFINITION

B. OVERALL EMPHASIS

C. TYPES OF SYSTEMS ANALYSIS

D. WHY IS IT IMPORTANT?

E. SYSTEMS ANALYSIS USE

F. THE TERM OF SYSTEM ANALYSIS

BACKGROUND CONCEPT OF SYSTEMS

AN EXAMPLE OF SYSTEM ANALYSIS: SDLC


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A. Background1. Many students failed to get the best academic

performance because they do not develop agood system of study

2. Many failed systems were abandoned becauseanalysts tried to build wonderful systemswithout understanding the organization.

3. The primarily goal is to create value for the

organization.

INTRODUCTION


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3. Systems are becoming more complex, moresophisticated, and harder to understand

4. The characteristic attributes of a problem situationwhere systems analysis is called upon arecomplexity of the issue and uncertainty of theoutcome of any course of action that might

reasonably be taken5. The heavy reliance of most organisations on

information processing means that the analyst mustbe more accurate, and skilful, than ever before.

6. Systems analysis is an explicit formal inquiry carriedout to help someone (referred to as the decisionmaker) identify a better course of action and make abetter decision than he might otherwise have made


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A. DEFINITION

What is Systems Analysis and Design (SAD)? Systems analysis means understanding the

existing system and defining the logicalrequirements for a new system prior to

designing the system System analysis is the analysis of the role of a

proposed system and the identification of therequirements that it should meet.

System analysis is the study of an activity orprocedure to determine the desired end and themost efficient method of obtaining this end


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Systems analysis is the interdisci-

plinary part of science, dealing withanalysis of

sets of interacting entities, the systems,often prior to their automation as computersystems, and

the interactions within those systems.This field is closely related to operationsresearch.

Bagian saininterdisiplin yangberhubungandengananalisisserangkaian entitas yang berinteraksi (sistem), seringsebelum otomatisasi seperti sistem komputer,daninteraksidalam sistem


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Systems Analysis: understanding and specifyingin detailwhat an information system should do

Attempts to understand how the existing

system helps solve the problem identified insystems investigation

System Design: specifying in detail howtheparts of an information system should be

implemented


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Systems analysis is an explicit formal

inquiry carried out to help someone(referred to as the decision maker)identify a better course of action andmake a better decision than he might

otherwise have made Penyelidikan formaltegas untuk membantu

seseorang(pembuat keputusan)mengidentifikasisuaturangkaianaksi yanglebih baik dari yang

dapat sebaliknya buat


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The systems analyst is a key person analyzing the business,

identifying opportunities for

improvement, and

designing information systems to

implement these ideas. It is important to understand and

develop through practice the skills

needed to successfully design andimplement new informationsystems.


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B. OVERALL EMPHASIS

To gather data on the existing system

and the requirements for the new

system (mengumpulandatatentangsistem yg

adadan kebutuhanakan sistem yangbaru) To consider alternative solutions to the

problem and the feasibility of the

solutions (mempertimbangkan solusialternatifakanproblemdan kelayakan

solusi)


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C. TYPES OF SYSTEMS ANALYSIS

Accident Analysis

Business analysis

Morphological analysis

Software prototyping

Spiral model

Waterfall model


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INTRODUCTIONINTRODUCTION

D. WHY IS IT IMPORTANT?

Success of information systems depends on goodSAD

Widely used in industry - proven techniques

Part of career growth in IT - lots of interesting andwell-paying jobs!

Increasing demand for systems analysis skills


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E. SYSTEMS ANALYSIS USE

1. The characteristic attributes of a problem situation wheresystems analysis is called upon are complexity of theissue and uncertainty of the outcome of any course ofaction that might reasonably be taken.

2. Systems analysis usually has some combination of the

following: identification and re-identification) ofobjectives, constraintS, and

alternative courses of action;

examination of the probable consequences of the alternatives interms of costs, benefits, and risks;

presentation of the results in a comparative framework so thatthe decision maker can make an informed choice from among thealternatives.


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3. The typical use of systems analysis is to guide decisions

on issues such as national or corporate plans andprograms, resource use and protection policies,research and development in technology, regional andurban development, educational systems, and othersocial services.

4. Clearly, the nature of these problems requires aninterdisciplinary approach. There are several specifickinds or focuses of systems analysis for whichdifferent terms are used:

A systems analysis related to public decisions is often referredto as a POLICY ANALYSIS.

A systems analysis that concentrates on comparison andranking of alternatives on basis of their known characteristics is

referred to as DECISION ANALYSIS.


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CONCEPT OF SYSTEMS

Basic TermsSystem: An organized relationship among the

functioning units or components, which work in syncto achieve a common goal.

System Study: A study of operations of a set ofconnected elements and the inter connectionsbetween these elements. It clearly shows that no onecan ignore an element while doing a system study.

System Approach: Shows a set of procedure tosolve a particular problem, It applies scientific methods

to understand the inter relationship between theelements to solve the problem.System analysis: It is a management exercise, which

helps us in designing a new system or improving theexisting system.


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Concept of Systems

Characteristics of a system. A system can bedescribed as having nine characteristics

1. Components

2. Interrelations (of Components)

3. Boundary

4. Purpose5. Environment

6. Interfaces

7. Constraints

8. Input9. Output


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Characteristics of a System

1. Components

Irreducible part

Or

Aggregation of parts that make a single object (e.g., a modemis a single object that is actually made of lots of circuits andswitches, etc.)

Aggregations are called subsystems


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2. Interrelations (of Components) Function of one component ties it to the function of others

within the system

Systemis workingtowardsomepurpose


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3) Boundary what separates the system from its environment

the system lies within the boundary


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4) Purpose Overall goal or function ofthe system

In structured systemsdesign, one rule is anysystem you cannot

describe in a single phraseis actually more than onefunction

But complex system has lots of subsystems with their own functions

e.g. human system is to live but w/ sub systems to breed(reproductive system), eat (digestive system), etc.


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5) Environment Made up of

components as well

Are components

important? Yes

Are componentsunder our control?No

Note that we do influence environment with outputs. But do notcontrol

Examples: political, social, economical, ecological


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6)Interfaces Points at which thesystem meets itsenvironment

Also exist betweensubsystems

In computer systems external interfaces are Public and internal

are Private Private interfaces can either be for privacy or to eliminate

extraneous information (and reduce potential mistakes or infooverload.


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7) ConstraintsLimitations

Can be internal (e.g.,resources)

Can be external (e.g.,

rules and realities)

Constraints are limits to what a system can do as a result ofexternal rules and realities or internal decisions


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8) Input A system takes input from its environment in order to function

Starts the cascade of the system


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9) Output Output is what a systemreturns to itsenvironment as a result ofachieving its purpose

In information systems,you have inputs,processing, and outputs ofdata

Process is the function of the (sub)systemInputs are what data it takes in

Outputs are the data or information result of the processing Example, fdouble(x) = x*2 is function.

If input is 5, output is 10.


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Modeling- Whatis modeling?

Data reduction of key points

Omits extraneous points

What makes detail extraneous?

Many levels of abstraction Why multiple levels?

What items go on a given model level (does thegalaxy belong on the same level of abstraction as a

skin cell when describing the universe?)

Concept of Systems


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THANK YOU

MATURNUWN


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AN EXAMPLE OF SYSTEMANALYSIS:

SYSTEMS DEVELOPMENT LIFE

CYCLE (SDLC)


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Systems Development Life Cycle

With the concept of systems in mind, lets talk about how

we build information systems We design/build/integrate information systems with what is

called the Software Development Lifecycle (SDLC)

SDLC is a description of any of the methods used bycompanies to create and maintain systems that perform basic

business functions Main goal is to improve employee efficiency by applying

software solutions to key business tasks A validated methodology should be used in order to improve odds of

success. Methodologies are used to manage the SDLC. We talk about

methodologies later. Note: the book calls SDLC itself a methodology, but I disagree with use

of term in that way. Generally speaking, methodologies are used tocomplete the SDLC, in whatever form it takes


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So whatexactlyis the SDLC?

The systems developmentlifecycle(SDLC) is the process of understanding how an information

system (IS) can support business needs, designing the

system, building it, and delivering it to users

a series of steps used to manage the phases ofdevelopment for an information system

Phases are not necessarily sequential

Each phase has a specific outcome and deliverable

Individual companies use customized life cycle (different

phases, sub-phases, sequence) An alternative view from the books (the Spiral model) is shown

in the final slide FYI


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Major Attributes of the Life Cycle

The project -- Moves systematically through phases where

each phase has a standard set of outputs

Produces project deliverables

Uses deliverables in implementation

Results in actual information system

Uses gradualrefinement


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Systems Development Life Cycle (SDLC)

Four phase SDLC in book is simply used as a example

and is useful for purpose of teaching about systemsanalysis and design (SA&D):

1. Planning and Selection2. Analysis

3. Design

4. Implementation and Operation


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Project Phases

Planning Why build the system? How should the team go about building it?

Analysis

Who uses system, what will it do, where and when will the system be used?

Design How will the system work?

Implementation System delivery


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A simple process for making lunch


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Project initiation

1. Identifying business valueIdentifying needs

Selecting from alternatives

Rough out solution plan

2. Analyze feasibility

Project management

1. Develop work plan

2. Staff the project3. Control and direct project

Planning


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The Planning phase is the fundamental

process of understanding why aninformation system should be built.

The Planning phase will also determine

how the project team will go about buildingthe information system.

The Planning phase is composed of two

planning steps.


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1. During project initiation, the systems

business value to the organization is

identified (How will it lower costs 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 theproject through the entire SDLC.


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Analysis strategy

Gathering business requirements

Requirements definition use cases

Process modeling

Data modeling

Analysis


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Analysis strategy

Gathering business requirements

Requirements definition use cases

Process modeling

Data modeling

Analysis


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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 guidethe projects teams efforts. This includes ananalysis of the current system.

2. Requirements gathering: The analysis of this

information leads to the development of aconcept for a new system. This concept is usedto build a set of analysis models.

3. System proposal: The proposal is presented

to the project sponsor and other key individualswho decide whether the project shouldcontinue to move forward.


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The system proposal is the initial deliverable thatdescribes 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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Design selection

Architecture design

I

nterface design Data storage design

Program design

Design


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In this phases it is decided how the system will operate, in terms of the

hardware, software, and networkinfrastructure;

the user interface, forms, and reports that willbe used; and

the specific programs, databases, and files that

will be needed.


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Five Design Steps

1. Design Strategy:

This clarifies whether thesystem will be developed by the companyor outside the company.

2. Architecture Design:This describes thehardware, software, and network

infrastructure that will be used.3. Database and File Specifications:These

documents define what and where the datawill be stored.

4. Program Design:

Defines what programsneed to be written and what they will do.


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Construction

Program building

Program and system testing

Installation Conversion strategy

Training plan

Support plan

Implementation


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During this phase, the system is eitherdeveloped or purchased (in the case of

packaged software).

This phase is usually the longest and mostexpensive part of the process.

The phase has three steps.

Implementation


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Three Implementation Steps

1.System Construction: The systemis built and tested to make sure it

performs as designed.2.Installation: Prepare to support the

installed system.

3.Support Plan: Includes a post-implementation review.


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Summary1. The Systems Development Lifecycle consists of four stages:

Planning, Analysis, Design, andImplementation

2. There are six major development methodologies:

the waterfall method, the parallel development method, the phased development method, system prototyping, design prototyping, and agile development.

3. There are five major team roles: business analyst, systems analyst, infrastructure analyst, change management analyst and project manager.


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SystemsAnalysisand DesignSystemsAnalysisand Design,, 22ndndEdition:Edition: Alan Dennisand Barbara Haley Wixom John Wiley & Sons, Inc.

Prepared by: RobertaM. Roth, University ofNorthern Iowa

PowerPointPresentation forDennis & Haley Wixom, Systems Analysis and Design, 2ndEdition Copyright 2003 John Wiley & Sons, Inc. Allrightsreserved.

AP/ITEC 3010.03 Systems Analysis and Design, IAP/ITEC 3010.03 Systems Analysis and Design, ICourseCourse

IntroductionIntroduction Prof. PeterKhaiter

Email [email protected], Class web sitehttp://www.atkinson.yorku.ca/~pkhaiter/ITECw103010N.htm


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Copyright 2003

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