1. 1

2. CHAPTER D2
TRANSION TO
SYSTEM DESIGN
( Selecting the Best Alternative
Design Strategy)
2

3. Chapter Objectives
● Describe software trends, including the
concept of software as a service
● Explain software acquisition alternatives,
including traditional versus Web-based
software development strategies
● Selecting the Best Alternative Design
Strategy
 Learn to assemble the various pieces of an
alternative design strategy.
 Learn how to generate at least three
alternative design strategies.
 Discuss selecting the best design strategy
using both qualitative and quantitative
methods 3

4. Chapter Objectives
 Learn how to use the results of the analysis
phase to update a Baseline Project Plan
(BPP).
* Describe software outsourcing options,
including offshore outsourcing and the role
of service providers Explain the transition
from systems analysis to systems design,
● Explain the transition to systems design and
the importance of prototyping
● Discuss guidelines for systems design
4

5. Alternative generation and selection
● Alternative generation and selection is
the third major analysis activity.
(Requirements determination,
structuring requirements, alternatives
generation and selection)
● During alternative generation and
selection, the system’s structured
requirements are transformed into
several alternative design strategies,
and the best way to acquire the new
system is identified
5

6. Development Strategies Overview
● Selecting the best development path is
an important decision that requires
companies to consider three key
topics
– The impact of the Internet
– Software outsourcing options
– In-house software development alternatives
6

7. The Impact of the Internet
● The Internet has triggered enormous
changes in business methods and
operations, and software acquisition is
no exception
● This section examines a trend that:-
 views software as a service,
 changing market-place for software,
 how Web-based development
compares to traditional methods
7

8. The Impact of the Internet
● Software as a Service
– The Software and Information Industry Association
(SIIA) is an industry group that focuses on the digital
economy
– SIIA believes that the concept of software as a service
is redefining the way that companies develop and
deploy their information systems
8

9. The Impact of the Internet
● The Changing Software Marketplace
– In the traditional model, software vendors develop
and sell application packages to customers
– In addition to traditional vendors, the marketplace
now includes many forms of outsourcing, including
application service providers and firms that offer
Internet business services
9

10. The Impact of the Internet
● The Impact of the Internet on Systems
Development
– Developers will focus on Web-based application
development, where the Web becomes an integral
part of the application rather than just a
communication channel
• IBM’s WebSphere
• Microsoft’s .NET
10

11. The Impact of the Internet
● The Impact of the Internet on
Systems Development
– Traditional development
• Systems design is influenced by compatibility issues
• Systems are designed to run on local and wide-area
company networks
• Web-based features are treated as enhancements rather
than core elements of the design
11

12. The Impact of the Internet
● The Impact of the Internet on
Systems Development
– Web-based development
• Systems are developed and delivered in an Internet-
based framework such as .NET or WebSphere
• Internet-based development treats the Web as the
platform, rather than just a communication channel
• Web-based software usually requires additional layers,
called middleware
12

13. 13

14. Selecting the Best Alternative Design
Strategy
● Two basic steps:
1. Generate a comprehensive set of alternative design
strategies
2. Select the one design strategy that is most likely to
result in the desired information system
● Process:
1. Divide requirements into different sets of
capabilities
2. Enumerate different potential implementation
environments that could be used to deliver the
different sets of capabilities
3. Propose different ways to source or acquire the
various sets of capabilities for the different
7.14 implementation environments 14

15. Selecting the Best Alternative Design
Strategy(continued)
● Deliverables
1. At least three substantially different system design
strategies for building the replacement
information system
2. A design strategy judged most likely to lead to the
most desirable information system
3. A Baseline Project Plan (BPP) for turning the
most likely design strategy into a working
information system
7.15 15

16. Generating Alternative Design
Strategies
● Best to generate three alternatives:
– Low-End
• Provides all required functionality users demand
with a system that is minimally different from the
current system
– High-End
• Solves problem in question and provides many
extra features users desire
– Midrange
• Compromise of features of high-end alternative
with frugality of low-end alternative
7.16 16

17. Drawing Bounds on Alternative Designs
● Minimum Requirements
– Mandatory features versus desired features
– Forms of features
• Data
• Outputs
• Analyses
• User expectations on accessibility, response time,
and turnaround time
– Constraints on System Development:
• Time
• Financial
• Elements of current system that cannot change
• Legal
• Dynamics of the problem
7.17 17

18. Criteria for Choosing
Off-the-Shelf Software
● Cost
– In-house versus purchased
● Functionality
– Mandatory, essential, and desired features
● Vendor Support
– Installation
– Training
– Technical support
● Viability of Vendor
7.18 18

19. Criteria for Choosing
Off-the-Shelf Software (continued)
● Flexibility
– Ease of customization
● Documentation
– User documentation
– Technical documentation
● Response Time
● Ease of Installation
7.19 19

20. 7.20 20

21. Validating Purchased Software
Information
● Information from Vendor
● Software Evaluation Period
● Customer References from Vendor
● Independent Software Testing Service
● Trade Publications
7.21 21

22. Hardware and Software Issues
Existing Platform New Hardware and System
1. Lower costs Software
2. Information system staff is 1. Some software
familiar with operation and components will only
run on new platform
maintenance
2. Developing system for
3. Increased odds of new platform gives
successfully integrating organization
system with existing opportunity to upgrade
applications technology holdings
4. No added costs of 3. New requirements may
converting old systems to allow organization to
new platform or radically change its
transferring data computing operations
7.22 22

23. Hardware and Software Issues (continued)
● Request for Proposal (RFP)
– A document provided to vendors to ask them to
propose hardware and system software that will meet
the requirements of your new system
7.23 23

24. Implementation Issues
● Technical and social aspects of
implementation need to be addressed
● Training
● Disruption of Work
7.24 24

25. 25

26. Outsourcing
● The Growth of Outsourcing
– Outsourcing has become part of an overall IT
strategy for many organizations
– On Demand
– A firm that offers outsourcing solutions is called a
service provider
- Application service providers (ASP)
– Internet business services (IBS)
• Also called managed hosting
26

27. Outsourcing
● Outsourcing Fees
– A fixed fee model uses a set fee based on a
specified level of service and user support
– A subscription model has a variable fee based on
the number of users or workstations that have
access to the application
– A usage model or transaction model charges a
variable fee based on the volume of transactions
or operations performed by the application
27

28. Outsourcing
● Outsourcing Issues and Concerns
– Mission-critical IT systems should be out-sourced
only if the result is a cost-attractive, reliable,
business solution that fits the company’s long-term
business strategy
– Outsourcing also can affect day-to-day company
operations and can raise some concerns
– Outsourcing can be especially attractive to a
company whose volume fluctuates widely, such as a
defense contractor
– Many firms are sending IT work overseas at an
increasing rate (Offshore/global outsourcing)
28

29. 29

30. Software Development Options
● A company can choose to develop its
own systems, or purchase, possibly
customize, and implement a software
package
● The most important consideration is
total cost of ownership (TCO)
● Companies also develop user
applications designed around
commercial software packages
30

31. Software Development Options
● Customizing a Software Package
1. You can purchase a basic package that vendors
will customize to suit your needs
2. You can negotiate directly with the software
vendor to make enhancements to meet your
needs by paying for the changes
3. You can purchase the package and make your
own modifications, if this is permissible under
the terms of the software license
31

32. Software Development Options
● Creating User Applications
– A user application utilizes standard business software
– User interface
– Help desk or information center (IC)
– Screen generators
– Report generators
32

33. Role of the Systems Analyst
● When selecting hardware and
software, systems analysts often
work as an evaluation and selection
team
● The primary objective of the
evaluation and selection team is to
eliminate system alternatives that
will not work, rank the system
alternatives that will work, and
present the viable alternatives to
management for a final decision
33

34. Analyzing Cost and Benefits
● Financial Analysis Tools
– Payback Analysis
– Return on investment (ROI)
– Net present value (NPV)
34

35. Analyzing Cost and Benefits
● Cost-Benefit Analysis Checklist
– List each development strategy being considered
– Identify all costs and benefits for each alternative. Be
sure to indicate when costs will be incurred and
benefits realized
– Consider future growth and the need for scalability
– Include support costs for hardware and software
– Apply the financial analysis tools to each alternative
– Study the results and prepare a report to
management
35

36. 36

37. The Software Acquisition Process
● Step 1: Evaluate the Information
System Requirements
– Prepare a request for proposal or quotation
• Request for proposal (RFP)
• Evaluation model
• Request for quotation (RFQ)
37

38. The Software Acquisition Process
● Step 2: Identify Potential Vendors or
Outsourcing Options
– The Internet is a primary marketplace
– Another approach is to work with a consulting firm
– Another resource is the Internet bulletin board
system that contains thousands of forums, called
newsgroups
38

39. The Software Acquisition Process
● Step 3: Evaluate the Alternatives
– Existing users
– Application testing
– Benchmarking - benchmark
– Match each package against the RFP features and
rank the choices
39

40. The Software Acquisition Process
● Step 4: Perform Cost-Benefit Analysis
– Identify and calculate TCO for each option you are
considering
– When you purchase software, what you are buying is
a software license
– If you purchase a software package, consider a
supplemental maintenance agreement
40

41. The Software Acquisition Process
● Step 5: Prepare a Recommendation
– You should prepare a recommendation that
evaluates and describes the alternatives, together
with the costs, benefits, advantages, and
disadvantages of each option
– At this point, you may be required to submit a
formal system requirements document and deliver a
presentation
41

42. The Software Acquisition Process
● Step 6: Implement the Solution
– Implementation tasks will depend on the solution
selected
– Before the new software becomes operational, you
must complete all implementation steps, including
loading, configuring, and testing the software; training
users; and converting data files to the new system’s
format
42

43. Completion of Systems Analysis Tasks
● Presentation to Management
– Based on their decision, your next task will be one
of the following
1. Implement an outsourcing alternative
2. Develop an in-house system
3. Purchase or customize a software package
4. Perform additional systems analysis work
5. Stop all further work
43

44. 44

45. The Transition to Systems Design
● If management decides to develop the
system in-house, then the transition
to the systems design phase begins
● Preparing for Systems Design Tasks
– It is essential to have an accurate and understandable
system requirements document
45

46. The Transition to Systems Design
● The Relationship between Logical and
Physical Design
– The logical design defines the functions and features
of the system and the relationships among its
components
– The physical design of an information system is a
plan for the actual implementation of the system
46

47. 47

48. Systems Design Guidelines
● The systems analyst must understand
the logical design of the system before
beginning the physical design of any
one component
– Data design
– User interface
– Systems design specification
48

49. Systems Design Guidelines
● Systems Design Objectives
– The goal of systems design is to build a system that
is effective, reliable, and maintainable
49

50. Systems Design Guidelines
● System Design Objectives
– User Considerations
– Data Considerations
• Data should be entered into the system where and when it
occurs because delays cause data errors
• Data should be verified when entered to catch errors
immediately
• Automated methods of data entry should be used whenever
possible
• Access for data entry should be controlled and all entries or
changes to critical data values should be reported – audit
trails
50

51. Systems Design Guidelines
● System Design Objectives
– Data Considerations
• Data should be entered into a system only once
• Data duplication should be avoided
– Architecture considerations
• Use a modular design
• Design modules that perform a single function are easier to
understand, implement, and maintain
51

52. Systems Design Guidelines
● Design Trade-Offs
– Design goals often conflict with each other
– Most design trade-off decisions that you will face
come down to the basic conflict of quality versus
cost
– Avoid decisions that achieve short-term savings but
might mean higher costs later
52

53. Prototyping
● Prototyping produces an early, rapidly
constructed working version of the
proposed information system, called a
prototype
● Prototyping Methods
– System prototyping
– Design prototyping
– Throwaway prototyping
53

54. Prototyping
● Prototyping Methods
– Prototyping offers many benefits
• Users and systems developers can avoid misunderstandings
• Managers can evaluate a working model more effectively
than a paper specification
– Consider potential problems
• The rapid pace of development can create quality problems
• In very complex systems, the prototype becomes unwieldy
and difficult to manage
54

55. Prototyping
● Prototyping Tools
– Systems analysts can use powerful tools to develop
prototypes
• CASE tools
• Application generators
• Report generators
• Screen generators
• Fourth-generation language (4GL)
• Fourth-generation environment
55

56. Prototyping
● Limitations of Prototypes
– A prototype is a functioning system, but it is less
efficient than a fully developed system
– Systems developers can upgrade the prototype into
the final information system by adding the necessary
capability
– Otherwise, the prototype is discarded
● Other Modeling Tools
– Systems flowchart
– American National Standards Institute (ANSI)
56

57. Chapter Summary
● This chapter describes system
development strategies, the
preparation and presentation of the
system requirements document, and
the transition to the systems design
phase of the SDLC
● An important trend that views
software as a service, rather than a
product, has created new software
acquisition options
● Systems analysts must consider Web-
based development environments
57

58. Chapter Summary
● Identify requirements and constraints
● Generate alternative design strategies
● Select the best design strategy
● Update the Baseline Project Plan (BPP) The
systems analyst’s role in the software
development process depends on the
specific development strategy
● The most important factor in choosing a
development strategy is total cost of
ownership (TCO)
● The process of acquiring software involves a
series of steps
58

59. 59

60. Hoosier Burger’s New Inventory Control
System
● Replacement for existing system
● Figure 7-4 ranks system requirements
and constraints
7.60 60

61. 7.61 61

62. Hoosier Burger’s New Inventory Control
System (continued)
● Figure 7-5 shows steps of current
system
● When proposing alternatives, the
requirements and constraints must be
considered
7.62 62

63. 7.63 63

64. Hoosier Burger’s New Inventory Control
System (continued)
● Figure 7-7
lists 3
alternatives:
– Alternative A is
a low-end
proposal
– Alternative C is
a high-end
proposal
– Alternative B is
a midrange
proposal
7.64 64

65. Hoosier Burger’s New Inventory Control
System (continued)
● Selecting the Most Likely Alternative
– Weighted approach can be used to compare the three
alternatives
– Figure 7-8 shows a weighted approach for Hoosier Burger
– Left-hand side of table contains decision criteria
• Constants and requirements
• Weights are arrived at by discussion with analysis team, users,
and managers
– Each requirement and constraint is ranked
• 1 indicates that the alternative does not match the request
well or that it violates the constraint
• 5 indicates that the alternative meets or exceeds
requirements or clearly abides by the constraint
● Selecting the Most Likely Alternative
– According to the weights used, alternative C appears to be the
7.65 best choice 65

66. 7.66 66

67. Updating the Baseline Project Plan (BPP)
● The Baseline Project Plan (BPP) was
developed during systems planning and
selection phase
● Baseline Project Plan (BPP) can be used as an
outline of a status report at analysis phase
● Schedule will be updated to reflect actual
activities and durations
● An oral presentation of project status is
typically made at this phase
7.67 67

68. PVF WebStore:
Selecting the Best Alternative Design Strategy
● Requirements and constraints were
compiled by consultant and team (see
Table 7-4)
7.68 68

69. 7.69 69

70. PVF WebStore:
Selecting the Best Alternative Design Strategy
 Proposed system is a scalable, three-tier approach
 Scalable
 The ability to seamlessly upgrade the system
through either hardware upgrades, software
upgrades or both
 Three-tier
 Web Server
 Provides connection to the Internet and
presentation of HTML page
 Applications Server
 Middle layer of software and hardware that lies
between Web server and corporate network
 Corporate network
7.70  Existing organizational computing infrastructure
70

71. 7.71 71

72. 72

73. WEB SEARCHES
● software acquisition alternatives,
● Selecting the Best Alternative Design
Strategy
● software outsourcing options
● Analyzing Cost and Benefits
– Financial Analysis Tools
• Payback Analysis
• Return on investment (ROI)
• Net present value (NPV)
• moodle.amriad.com
• Imaginecup.com
73