chapter 4&5 system analysis ppt.puyyyyyyyyyyyyyyyyyyyyyyyyptx

11/05/2024 System analysis and design by chieng.
B(MA)
1
CHAPTER FOUR
SYSTEM SELECTION AND PLANNING

B(MA)
2
1. Identifying and Selecting Projects
 The first activity of the systems planning and selection phase
of the SDLC is project identification and selection.
 The Process of Identifying and Selecting Information
Systems Development Projects
• Project Identification and selection consists of three
primary activities:
i. identifying potential development projects,
ii. classifying and ranking projects, and
iii. Selecting projects for development.

B(MA)
3
4.2 Initiating and Planning Systems
Development Projects
• Many activities performed during initiation and planning
could also be completed during the next phase of the SDLC—
systems analysis.
• Proper and insightful project initiation and planning, including
• determining project scope and identifying project
activities, can reduce the time needed to complete
later project phases, including systems analysis.
• For example, a careful feasibility analysis conducted
during initiation and planning could lead to rejecting a
project and saving a considerable expenditure of
resources.

B(MA)
4
Cont’d
• The Process of Initiating and Planning Systems Development
Projects
• As its name implies, two major activities occur during project
initiation and project planning.
 Project initiation focuses on activities that will help
organize a team to conduct project planning.
 During initiation, one or more analysts are assigned to
work with a customer to establish work standards and
communication procedures.

B(MA)
5
 Summary of six activities performed during project
initiation.
• Types of Activities Performed during Project Initiation
• Establishing the project initiation team
• Establishing a relationship with the customer
• Establishing the project initiation plan
• Establishing management procedures
• Establishing the project management
environment and project workbook
• Developing the project charter

B(MA)
6
Cont’d
Activities Performed during Project Planning
• Describing the project scope, alternatives, and feasibility
• Dividing the project into manageable tasks
• Estimating resources and creating a resource plan
• Developing a preliminary schedule
• Developing a communication plan
• Determining project standards and procedures
• Identifying and assessing risk
• Creating a preliminary budget
• Developing a project scope statement
• Setting a baseline project plan

B(MA)
7
Cont’d
• The systems analyst transforms a vague systems
request into a tangible project description during
project initiation and planning.
Systems analysts Result
 Customer of the proposed system
 gues system request
 technical staff
Tangible project description

B(MA)
8
Cont’d
2. The second activity, project planning, focuses on
defining clear, discrete tasks and the work needed
to complete each task.
• The objective of the project planning process is to
produce two documents:
i. a baseline project plan (BPP) and
ii. the project scope statement (PSS).

B(MA)
9
Cont’d
1. The BPP becomes the foundation for the remainder
of the development project. It is an internal
document used by the development team but not
shared with customers.
2. The PSS, produced by the project team, clearly
outlines the objectives of the project for the
customer

B(MA)
10
4.3 Assessing Project Feasibility
• Most information systems projects have budgets and
deadlines.
• Assessing project feasibility is a required task for a systems
analyst, to evaluate a wide range of factors. most feasibility
factors fall into the following six category
1. Economic
2. Operational
3. Technical
4. Schedule
5. Legal and contractual
6. Political

B(MA)
11
Cont’d
1. Economic feasibility
• A process of identifying the financial benefits and costs
associated with a development project.
i. Determining Project Benefit
a) Tangible benefit: A benefit, derived from the
creation of an information system, that can be
measured in dollars and with certainty.
 Most tangible benefits fit in one or more of the
following categories:
Cost reduction and avoidance
 Error reduction

B(MA)
12
Cont’d
Increased flexibility
Increased speed of activity
Improvement of management
planning and control
Opening new markets and
increasing sales opportunities

B(MA)
13
Cont’d
b) Intangible benefit: A benefit derived from the
creation of an information system, that cannot be
easily measured in dollars or with certainty.
Intangible benefits include:
• Competitive necessity
• Increased organizational flexibility
• Increased employee morale
• Promotion of organizational learning and
understanding
• More timely information

B(MA)
14
Cont’d
• After determining project benefits, project costs
must be identified.
ii. Determining Project Costs
• An information system can have both
tangible and
intangible costs.

B(MA)
15
Cont’d
a) Tangible cost A cost associated with an
information system that can be easily measured
in dollars and with certainty
• From a systems development perspective,
tangible costs include items such as
• hardware costs,
• labor costs, and
• Operational costs from employee training and
building renovations.

B(MA)
16
Cont’d
b) Intangible cost: A cost associated with an
information system, that cannot be easily measured
in terms of dollars or with certainty. Intangible costs
can include
• loss of customer goodwill,
• employee morale, or
• operational inefficiency.
• Besides tangible and intangible costs, you can
distinguish system-related development costs as
either one-time or recurring.

B(MA)
17
Cont’d
A one-time cost :refers to a cost associated with
project initiation and development and the start-up
of the system. These costs typically encompass the
following activities:
– System development
– New hardware and software purchases
– User training
– Site preparation
– Data or system conversion

B(MA)
18
Cont’d
A recurring cost :refers to a cost resulting from the
ongoing evolution and use of the system. Examples
of these costs typically include:
– Application software maintenance
– Incremental data storage expense
– Incremental communications
– New software and hardware leases
– Consumable supplies and other expenses (e.g.,
paper, forms, datacenter personnel)

B(MA)
19
Cont’d
• Both one-time and recurring costs can consist of
items that are fixed or variable in nature.
a) Fixed costs refer to costs that are billed or
incurred at a regular interval and usually at a
fixed rate. A facility lease payment is an example
of a fixed cost.
b) Variable costs refer to items that vary in relation
to usage. Long distance phone charges are
variable costs.

B(MA)
20
Cont’d
2. Operational feasibility
The process of assessing the degree to which a
proposed system solves business problems or takes
advantage of business opportunities
3. Technical feasibility
The process of assessing the development
organization’s ability to construct a proposed system
4. Schedule feasibility
The process of assessing the degree to which the
potential time frame and completion dates for all major
activities within a project meet organizational deadlines
and constraints for effecting change

B(MA)
21
Cont’d
5. Legal and contractual Feasibility
The process of assessing potential legal and
contractual ramifications due to the construction
of a system.
6. Political feasibility
The process of evaluating how key stakeholders
within the organization view the proposed system

B(MA)
22
4.4 Building the Baseline Project Plan
• All the information collected during project initiation
and planning is collected and organized into a
document called the baseline project plan.
• Once the BPP is completed, a formal review of the
project can be conducted with customers.
• This presentation, a walkthrough, will be discussed
later. The focus of the walkthrough is to verify all
information and assumptions in the baseline plan
before moving ahead with the project.

B(MA)
23
• An outline of a baseline project plan contains four
major sections:
1. Introduction
2. System description
3. Feasibility assessment
4. Management issues

B(MA)
24
1. The purpose of the introduction is to provide a brief
overview of the entire document and outline a
recommended course of action for the project.
The introduction is often limited to only a few
pages. Although it is sequenced as the first section
of the BPP, it is often the final section to be written.
One initial activity that should be performed is the
definition of the project scope, its range, which is an
important part of the BPP’s introduction section.

B(MA)
25
2. The second section of the BPP is the system description,
in which you outline possible alternative solutions to the
one deemed most appropriate for the given situation.
Note that this description is at a high level, mostly narrative in
form.
• Alternatives may be stated as simply as this:
– Web-based online system
– Mainframe with central database
– Local area network with decentralized databases
– Batch data input with online retrieval
– Purchasing of a prewritten package

B(MA)
26
3. In the third section of the BPP, feasibility
assessment, the systems analyst outlines project
costs and benefits and technical difficulties.
 This section is where high-level project schedules are
specified using
 Network diagrams and
 Gantt charts

B(MA)
27
4. The final section of the BPP, management issues,
outlines the concerns that management has about the
project.
Most projects, however, have some unique
characteristics that require minor to major deviation
from the standard methodology.
In the team configuration and management portion,
you identify the
 types of people to work on the project,
 who will be responsible for which tasks, and
 how work will be supervised and reviewed

B(MA)
28
4.5 Electronic Commerce Application: System Planning
and Selection
• Most businesses have discovered the power of Internet-
based electronic commerce as a means to communicate
efficiently with customers and to extend their marketing
reach.
• As a systems analyst, you and a project team may be
asked by your employer to
help determine whether an Internet-based
electronic commerce application fits the goals of
the company and,
if so, how that application should be
implemented..

B(MA)
29
• The systems planning and selection process for an
Internet-based electronic commerce application is no
different than the process followed for other
applications.
• Nonetheless, you should take into account special
issues when developing an Internet-based
application.

B(MA)
30
Three possible modes of electronic commerce.
1. Internet
A network of interconnected individual networks that
use a common protocol to communicate with each
other; a global computing network to support
business to consumer electronic commerce.
2. Intranet
Internet-based communication to support business
activities within a single organization.
3. Extranet
Internet-based communication to support business-
to-business activities.

B(MA)
31
Chapter ended
Thank for your cooperation!!!!

B(MA)
32
CHAPTER FIVE
SYSTEM ANALYSIS

B(MA)
33
5.1 Determining System Requirement
 Determining System Requirement
What is Requirements Determination?
A requirement is a vital feature of a new system which may include
o processing or capturing of data,
o controlling the activities of business,
o producing information and
o supporting the management.
Requirements determination involves studying the existing system and
gathering details to find out what are the requirements, how it works,
and where improvements should be made.

B(MA)
34
Major Activities in requirement Determination
1. Requirements Anticipation
o It predicts the characteristics of system based on previous
experience which include certain problems or features and
requirements for a new system.
2. Requirements Investigation
o It is studying the current system and documenting its features for
further analysis.
o It is at the heart of system analysis where analyst documenting
and describing system features using fact-finding techniques,
prototyping, and computer assisted tools.
3. Requirements Specifications
o It includes the analysis of data which determine the requirement
specification, description of features for new system, and
specifying what information requirements will be provided.

B(MA)
35
5.1.1 Traditional Methods for Determining requirements
1. Interviewing individuals
2. Interviewing groups
3. Observing workers
4. Studying business documents
1. Individual interviews: Meaning:-Interview one
person at a time
 Advantages:- Easier to schedule
Disadvantages:- contradiction and
inconsistence between interviewees.follow up
are time consuming

B(MA)
36
Cont’d
2. Group interviews:-Interview several key people
together
Advantages:-:
 -More effective use of time
 Can hear agreements and disagreement,
 Opportunity for synergies
Disadvantages
 More difficult to schedule

B(MA)
37
3. Direct Observation
– Watching users do their jobs
– Can provide more accurate information than self-
reporting (questionnaires and interviews
– Through the observation more information can be
collected.
4. Document Analysis
– Review of existing business documents
– Can give a historical and “formal” view of system
requirements
– The information can be the guideline to the workers
as the references.

B(MA)
38
Cont’d
 What is interviewing?
oOne of the interviewing is one of the primary ways
analyst gather information about an information
systems project.
oIt is a dialogue (two ways communication) with user or
manager to obtain their requirements.
• It has two type of choosing interview questions:
 Open-ended:
oUsually used to probe for information for which you
cannot anticipate all possible responses or for which
you do not know the precise questions to ask.

B(MA)
39
• Closed-ended:
– Structured, questions with limited range of possible
answers.
– Example: Which of the following would you say is
the one best thing about the information system
you currently use to do your job (pick one only)
a) Having easy access to all of the data you
need
b) The system’s response time
c) The ability to access the access the
system from remote locations.

B(MA)
40
• Guidelines for effective interviewing
1. Plan the interview.
 Prepare interviewee: appointment,
priming questions.
–Prepare agenda, checklist, questions.
2. Listen carefully and take notes (tape record if
permitted).
3. Review notes within 48 hours.
4. Be neutral.
5. Seek diverse views.

B(MA)
41
Traditional Methods for Determining requirements
Interviewing individuals
Interviewing groups
Observing workers
Studying business documents

B(MA)
42
5.1.2 Modern Methods for Determining
requirements
Modern methods for Collecting System Requirements:
Bringing together in a Joint Application Design (JAD)
session users, sponsors, analysts and others to discuss
and review system requirements.
Using group support systems to facilitate the sharing of
ideas and voicing opinions about system requirements.
using CASE tools to analyze current systems to discover
requirements to meet changing business conditions.
Iteratively developing system prototypes that refine the
understanding of system requirements in concrete by
showing working versions of system features.

B(MA)
43
5.2 Structuring System Requirements
INTRODUCTION
• Requirements structuring is the process to use
some kind of systematical and standard, well-
structured methods to model the real world.
• Traditionally, we use data flow diagram for
process modeling, decision table or decision
tree for logic modeling, and Entity-relationship
diagram for data modeling.

B(MA)
44
5.2.1 Process modeling
What is process modeling?
–Graphically representing the processes, or
actions, that capture, manipulate, store and
distribute data between a system and its
environment and among system
components
Data-flow Diagram (DFD): One of the main process
modeling tools graphically illustrates movement of
data between external entities and the processes and
data stores within a system

11/05/2024 45
Data-Flow Diagramming Mechanics
Data Flow
o Represent data that are in motion and moving
as a unit from one place to another in the
system
oDrawn as an arrow
oelect a meaningful name to represent the data
Data Store
oRepresent data at rest
oMay represent data in
 File folder
System analysis and design by
chieng.B(MA)

B(MA)
46
Computer-based file
Notebook
o Drawn as a rectangle with the right vertical line
missing
oLabel includes name of the store as well as the
number

B(MA)
47
Data-Flow Diagramming Mechanics (continued)
 Process
o Represent work or actions performed on data so that they
are transformed, stored, or distributed
– Drawn as a rectangle with rounded corners
– Number of process as well as name are recorded
Source/Sink
o Depicts the origin and/or destination of the data
o Sometimes referred to as an external entity
o Drawn as a square symbol
o Name states what the external agent is
o Because they are external, many characteristics are not of
interest to us

B(MA)
48
DFD Level /Process Modeling Steps
1. Context diagram
 Overview of the organization system
2. Level -0 diagrams
 Representation of the system's major process
at high level of abstraction
3. Level- 1 diagram
 Result from the decom[position of leel-0
4. Level-n diagram
 Result from decomposition of n-1

B(MA)
49
Purpose: converting gathered requirements into
diagrams using a systematic method
Step 1: Draw the Context Diagram
– A data-flow diagram (DFD) of the scope of an
organizational system that shows the system boundaries,
external entities that interact with the system and the
major information flows between the entities and the
system

B(MA)
50
Step 2: Identifying process(es) embedded in the
single process of the context diagram
– Your understanding of the gathered requirements helps you
list the major processes/actions taking place in existing
system or that should take place in the new system
– You may also identify some data stores along the processes

B(MA)
51
Step 3: Draw Level-0 Diagram
– Use identified processes to draw the data-flow
diagram (DFD) that represents a system’s major
processes, data flows, and data stores at a higher
level. It’s called Level-0 DFD

B(MA)
52
• Step 4: Decompose Level-0 DFD processes
– For each Level-0 process:
• Identify the sub-processes that need to be performed to complete the
process
• Identify key data stores along the identified sub-processes
• Draw the process’ Level-1 diagram
 Step 5: Decompose Level-1 DFD processes
– For each Level-1 process:
 Identify the sub processes that need to be performed to complete the
process
 Identify key data stores along the identified sub processes
 Draw the process’ Level-2 diagram

B(MA)
53
Data-Flow Diagramming Rules
Basic rules that apply to all DFDs:
oInputs to a process are always different than
outputs
oObjects always have a unique name
In order to keep the diagram uncluttered, you can
repeat data stores and data flows on a diagram
Process
1. No process can have only outputs (a miracle)
2. No process can have only inputs (black hole)
3. A process has a verb phrase label

B(MA)
54
 Data Store
1. Data cannot be moved from one store to another
2. Data cannot move from an outside source to a data
store
3. Data cannot move directly from a data store to a data
sink
4. Data store has a noun phrase label
Source/Sink
1. Data cannot move directly from a source to a sink
2. A source/sink has a noun phrase label

B(MA)
55
Guidelines for Drawing DFDs
1. Completeness
– DFD must include all components necessary for system
– Each component must be fully described in the project
dictionary or CASE repository
• Examples: data flows that do not lead anywhere or
data stores, processes
that are not connected to anything else
2. Consistency
– The extent to which information contained on one
level of a set
of nested DFDs is also included on other levels

B(MA)
56
Cont’d
3. Timing
– Time is not represented well on DFDs
– Best to draw DFDs as if the system has never started and will
never stop.
4. Iterative Development
– Analyst should expect to redraw diagram several times before reaching the
closest approximation to the system being
modeled
5. Primitive DFDs
o Lowest logical level of decomposition
o Decision has to be made when to stop decomposition
Rules for stopping decomposition:
o When each process has been reduced to a single decision, calculation or database
operation
o When each data store represents data about a single entity
o When the system user does not care to see any more detail

B(MA)
57
5.2.12 Logic modeling
 Data flow diagrams do not show the logic inside the processes
 what occurs within a a process?
 How input data is converted into output information.
 Logic modeling involves representing internal structure and
functionality of processes depicted on a DFD.
 Processes must be clearly described before
translating them into programming language.
 Logic modeling can also be used to show when
processes on a DFD occur.
 Logic modeling will be generic without taking syntax
of a particular programming language.

B(MA)
58
Logic Modeling Deliverables and Outcomes
• Each process on the lowest level DFD will be
represented by one or more of the following: -
Structured English
Decision Tables
Decision Trees
State-transition diagrams
Sequence diagrams
Activity diagrams

B(MA)
59
5.2.3 Conceptual Data Modeling
 A conceptual data model:-
 is a representation of organizational data.
The purpose of a conceptual data model is to show as many
rules about the meaning
and interrelationships among data as possible, independent of
any database
management system or other implementation considerations
 A conceptual data model
A detailed model that shows the
overall structure of organizational
data while being independent
of any database management
system or other implementation
considerations

B(MA)
60
5.3. Selecting the Best design Strategy
• Selecting the best alternative system involves at
least two basic steps:
1. generating a comprehensive set of alternative
design strategies, and
2. Selecting the one that is most likely to result
in the desired information system, given all of
the organizational, economic, and technical
constraints that limit what can
be done.

B(MA)
61
• A system design strategy :- represents a particular
approach to developing the system
• Selecting a strategy :- requires you to answer
questions about the system’s
functionality,
hardware and system software
platform, and method for acquisition.

B(MA)
62
The Process of Selecting the Best Alternative Design
Strategy
• Shaping alternative system design strategies involves
the following processes:
1. Dividing requirements into different sets of
capabilities, ranging from the bare minimum
that users would accept (the required
features)
 to the most elaborate and advanced system the
company could afford to develop (which
includes all the features desired by all users).

B(MA)
63
2. Enumerating different potential
implementation environments (hardware,
system software, and network platforms) that
could be used to deliver the different sets of
capabilities.
3. Proposing different ways to source or acquire
the various sets of capabilities for the different
implementation environments.

chapter 4&5 system analysis ppt.puyyyyyyyyyyyyyyyyyyyyyyyyptx

More Related Content

Similar to chapter 4&5 system analysis ppt.puyyyyyyyyyyyyyyyyyyyyyyyyptx (20)

More from jacobdiriba (8)

Recently uploaded (20)

chapter 4&5 system analysis ppt.puyyyyyyyyyyyyyyyyyyyyyyyyptx