ITEC 1010 Information and Organizations Chapter 11 Artificial Intelligence and Expert Systems.
Faculty of Arts Atkinson College ITEC 1010 A F 2002 Welcome Eighteenth Lecture for ITEC 1010 3.0 A...
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Transcript of Faculty of Arts Atkinson College ITEC 1010 A F 2002 Welcome Eighteenth Lecture for ITEC 1010 3.0 A...
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Welcome
Eighteenth Lecture for ITEC 1010 3.0 A
Professor G.E. Denzel
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Agenda
Continue discussion of Project Development and Systems Analysis, especially the SDLC
Review material from Lecture 7 on relational databases.
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
The Traditional SDLC(1) Systems Investigation
(2) Systems Analysis
(3) Systems Design
(4) Programming
(5) Testing
(6) Implementation
(7) Operation
(8) Maintenance
Go Back to a previous Stage or Stop
An eight-stage systems development life cycle (SDLC)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
System Investigation Feasibility study determines the probability of success of
proposed system’s development project. Includes …• Technical feasibility (will we be able to build the
system?)• Economic feasibility (how much will it cost to build
the system and how much will it benefit us?)• Behavioral feasibility (if we build the system, will it
be accepted and used?)
Phases in SDLC (1)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Systems Analysis Examines the business problem(s) that the organization
plans to solve with information systems Determines what the new system must do by examining:
• Strengths and weaknesses of the existing system
• Functions that the new systems must have to solve the business problem(s)
• User information requirements for the new system
Phases in SDLC (2)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Systems Design Describes how the system will fulfill the user
requirements Develop both logical design and physical design Output => technical design or system specification…
• system outputs, inputs, and user interfaces• hardware, software, databases, telecommunications,
personnel, and procedures• how these components are integrated
Phases in SDLC (continued)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Programming the translation of the design specifications into
computer code structured programming techniques improve the logical
flow of the program by decomposing the computer code into modules
Phases in SDLC (continued)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Figure 14.3 Flowchart diagram of a payroll application of structured programming.
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Implementation The process of converting from the old system to the
new system Four major conversion strategies
• Parallel conversion: the old and new systems operate simultaneously for a period of time
• Direct conversion: the old system is cut off and the new systems is turned on at a certain point in time
• Pilot conversion: introduces the new system in one part of the organization
• Phased conversion: introduces components of the new system in stages
Phases in SDLC (continued)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Testing Checks to see if the computer code will produce
the expected and desired results under certain conditions
Phases in SDLC (continued)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Operation the new system will operate for a period of
time, until it no longer meets its objectives
Maintenance (simultaneous with Operation) debugging the programs updating the system to accommodate changes in
business conditions adding new functionality to the system (which
loops back to the beginning of the SDLC)
SDLC Phases (cont’d)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Prototyping Starts with only a general idea of user requirements, and
develops models of the system ‘until it’s right’
Advantages: Speeds up the development approach Gives the users the opportunity to clarify their information
requirements Useful in the development of decision support systems and
executive information systems
Disadvantages: Replaces the systematic analysis and design stages of the
SDLC - quality may be sacrificed Can result in an excess of iterations
Alternatives to the SDLC
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Joint Application Design (JAD) A group-based method for collecting user requirements
and creating staged designs
Advantages: Saves time Greater support for, and acceptance of new systems Produces higher quality systems Easier implementation Lower training costs
Disadvantages: Very difficult to get all users to JAD meetings All the problems that may be caused by any group
process
Alternatives to the SDLC
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Rapid Application Development (RAD) A method that can combine JAD, prototyping, and
integrated CASE tools, to rapidly produce a high-quality system
Advantages: Active involvement of users in the development process Speeds the development process Reduces development costs Can create applications that are easier to maintain and
modify
Disadvantages: May result in systems with limited functionality and
adaptability for change
Alternatives to the SDLC
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Integrated Computer-Assisted Software Engineering (ICASE) Tools Automate many of the tasks in the SDLC
Advantages: Produces systems with a longer effective operational life Speeds up the development process and result in systems that
are more flexible and adaptable to changing business conditions
Results in excellent documentation
Disadvantages: More expensive to build and maintain initial system Requires more extensive and accurate definition of user
needs and requirements Difficult to customize and may be difficult to use with
existing systems
Alternatives to the SDLC
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Use of Computer-Aided Software Engineering (CASE) Tools
CASE tools automate tasks required in a system development effort and enforces adherence to the SDLC Upper CASE tools
• Tools that focus on activities associated with the early stages of systems development
Lower CASE tools• Tools that focus on the later implementation stage of systems
development
Integrated-CASE (I-CASE) tools• Tools that provide links between upper- and lower-CASE
packages, allowing lower-CASE packages to generate program code from upper-CASE package generated designs
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Object-Oriented Development A fundamentally different view of computer
systems Advantages:
• Reduces the complexity of systems development and leads to systems that are easier and quicker to build an maintain
• Improves programmers’ productivity and quality• More flexible• Allows systems analysts to think as users do about the
system• Ideal for developing Web applications• Depicts the system in user terms, increasing
understanding of what the new system does and how it meets its objectives
Alternatives to the SDLC
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Object-Oriented Development Disadvantages
• Runs more slowly• Need to retrain the programmers in OO
methodology
Alternatives to the SDLC
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Development Outside the IS Department
End User Development Users perform ad hoc programming to solve business
problems Factors that drive the trends toward increased end-user
computing and end-user development• More powerful, inexpensive desktop hardware• Increasingly diverse software capabilities• Increasingly computer literate population• Backlog of IS projects• Apparent cost savings
End-users (usually) don’t produce adequate documentation or perform adequate testing
Security may be breached
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
External Acquisition of Prewritten Software Factors to consider during make-or-buy decision
• On-time• On-budget• Full functionality• User acceptance• Favorable costs-to-benefits ratio• Low maintenance• Scalability• Integration with other systems• Minimal negative cross-impacts• Reusability
Development Outside the IS Department
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Application Service Providers (ASPs) Software obtained via subscription Software resides on ASP’s systems Software is accessed via Web or VPN Subscriber does not have to host software on
existing computer systems Updates and bug fixes are provided by the ASP ASP can provide help-desk support
Development Outside the IS Department
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Outsourcing Using third parties to provide some or all
functions and services of the IT department IT may not be a core competency of the firm;
better to hire outside specialists Advantages:
Outsourcer can obtain hardware capabilities less expensively due to economies of scale
Outsourcer can hire needed technical staff Outsourcer specializes in providing computer
services Ability to expense outsourcing fees provides tax
benefits
Development Outside the IS Department
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Outsourcing (continued) Disadvantages:
• Economies of scale may be of limited value• Staffing depends on outsourcers needs, not client’s• Lack of familiarity with business/industry• Contract problems• Internal cost reduction opportunities could eliminate
the advantage of outsourcers Guidelines:
• Write short-period contracts or have flexibility since business needs are dynamic
• Use of subcontractors should be controlled• Use selective outsourcing only for those functions
where it makes sense
Development Outside the IS Department
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Building Internet & Intranet Applications
Much future development will likely be Web pages due to their simplicity and ease of development
SDLC probably not followed due to simplified Web development
A Strategy for Internet/Intranet Development
Identify the objectives for organizational Web site(s) and pages
Include infrastructure requirements as well as security and legal issues in plans
Obtain/assign necessary personnel and provide oversight
Identify and prioritize potential projects
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Building Internet & Intranet Applications
JAVA - A Promising Tool Important programming language for putting
extra features into Web pages An object-oriented language designed for
implementation on networks Includes numerous security features to prevent
downloaded programs from damaging files or creating other problems on the receiving computer
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Relational Data Model
Relational data model All data elements are placed in two-dimensional
tables, called relations, that are the logical equivalent of files
Schematic
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Project Number Description Dept. Number
155 Payroll 257
498 Widgets 632
226 Sales manager 598
Dept. Number Dept. Name Manager SSN
257 Accounting 421-55-99993
632Manufacturin
g765-00-3192
598 Marketing 098-40-1370
SSN Last Name First Name Hire Date Dept. Number
005-10-6321 Johns Francine 10-7-65 257
549-77-1001 Buckley Bill 2-17-79 650
098-40-1370 Fiske Steven 1-5-85 598
Data Table 1: Project Table Data Table 2: Department Table
Data Table 3: Manager Table
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Relational Database Terminology Selecting
Data manipulation that eliminates rows according to certain criteria
Projecting Data manipulation that eliminates columns in a table
Joining Data manipulation that combines two or more tables
Linked Related tables in a relational database together
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Linking Data Tables to Answer an Inquiry
Schematic
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Project Number Description Dept. Number
155 Payroll 257
498 Widgets 632
226 Sales manager 598
Dept. Number Dept. Name Manager SSN
257 Accounting 421-55-99993
632 Manufacturing 765-00-3192
598 Marketing 098-40-1370
SIN Last Name First Name Hire Date Dept. Number
005-10-6321 Johns Francine 10-7-65 257
549-77-1001 Buckley Bill 2-17-79 650
098-40-1370 Fiske Steven 1-5-85 598
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Relational Database Terminology Relation <==> Table <==> Entity Tuple <==> Row <==> Record Attribute <==> Column <==> Field Primary Key is one or more columns whose values
together uniquely identify a row in a table Normalization is the process of making the
structure and contents of a database comply with some level of the Normal Form hierarchy (usually only the first three levels, but there are (at least) seven layers of increasing stringency.)
Faculty of ArtsAtkinson College
ITEC 1010 A F 2002
Relational Database Terminology
Why Normalization?Ensure data consistency and stabilityMinimize data redundancyEnsure consistent updatability and
maintainability of dataAvoid update/delete anomalies which
result in ambiguous data or inconsistent results