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Information Systems

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Information System (CS507)
The first increment is usually the core product which addresses the basic requirements of the system. This
maybe either be used by the client or subjected to detailed review to develop a plan for the next increment.
This plan addresses the modification of the core product to better meet the needs of the customer, and the
delivery of additionally functionality. More specifically, at each stage
The client assigns a value of functionality to each module not yet implemented
The developer estimates cost of developing each module
The resulting value-to-cost ratio is the criterion used for selecting which module is delivered next
Essentially the module with the highest value-to-cost ratio is the one that provides the client with the most
functionality (value) for the least cost. Using this method the client has a usable product at all of the
development stages. Modules are also selected on the basis of the customer requirements and needs apart
from the value to cost ratio.
20.1 Characteristics of the Incremental Model
The system development is broken into many mini development projects
Partial systems are successively built to produce a final total system.
Highest priority requirements tackled early on.
Once an incremented portion is developed, requirements for that increment are frozen.
20.2 Incremental Model-Evaluation
Benefits
Working functionality is produced earlier ­ computation of value to cost ratio
Reduces risks of change in user requirements
Provides clients flexibility in decision making.
Risk management is incremental
Smaller scope for change in user requirements
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Criticism
Larger picture cannot be seen until the entire system is built
Difficult to break down the total system at early stage of product development to determine reasonable
increments
Iterative Models
Iterative models are an approach for developing systems based on producing deliverables
frequently/repetitively. Each iteration, consisting of requirements, analysis & design, implementation and
testing, results in the release of an executable subset of the final product. These subsets grows incrementally
from iteration to iteration to become the final system. The Procedure itself consists of three basic steps.
The Initialization step -- creates a base version of the system. The goal for this initial implementation is
to create a product to which the user can react.
The Iteration step -- The iteration step involves
The redesign and implementation of a task from project control list. The goal for the design and
implementation of any iteration is to be simple, straightforward, and modular, supporting redesign
at that stage or as a task added to the project control list.
The analysis of the current version of the system. The analysis of an iteration is based upon user
feedback and the program analysis facilities available. It involves analysis of the structure,
modularity, usability, reliability, efficiency, and achievement of goals. The project control list is
modified in light of the analysis results.
The Project Control List -- To guide the iteration process, a project control list is created that
contains a record of all tasks that need to be performed. It includes n
New features to be implemented, and
Areas of redesign of the exiting solution.
The control list is constantly being revised as a result of the analysis phase.
20.3 Iterative Models ­ Evaluation
Harms
The Iterative Model can lead to "scope creep," since user feedback following each phase may lead to
increased customer demands. As users see the system develop, they may realize the potential of other
system capabilities which would enhance their work.
Benefits
In fact, the context of multiple iterations provides advantages in the use of measuring various aspects
of product development, such as
Effort to date
Changes,
Defects,
Logical, physical, and dynamic attributes,
Environmental considerations.
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The customer can tell how product characteristics like size, complexity, coupling, and cohesion are
increasing or decreasing over time.
One can monitor the relative change of the various aspects of the product or can provide bounds for
the measures to signal potential problems and anomalies.
20.4 Incremental vs. Iterative
These sound similar, and sometimes are equated but there is a subtle difference:
Incremental: add to the product at each phase
Iterative: re-do the product at each phase
Example
Building a House
Incremental: Starts with a modest house, keep adding rooms and upgrades to it.
Iterative: The design/construction map of the house is amended and improved and repeated
until all the requirements are fulfilled.
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Table of Contents:
  1. Need for information, Sources of Information: Primary, Secondary, Tertiary Sources
  2. Data vs. Information, Information Quality Checklist
  3. Size of the Organization and Information Requirements
  4. Hierarchical organization, Organizational Structure, Culture of the Organization
  5. Elements of Environment: Legal, Economic, Social, Technological, Corporate social responsibility, Ethics
  6. Manual Vs Computerised Information Systems, Emerging Digital Firms
  7. Open-Loop System, Closed Loop System, Open Systems, Closed Systems, Level of Planning
  8. Components of a system, Types of Systems, Attributes of an IS/CBIS
  9. Infrastructure: Transaction Processing System, Management Information System
  10. Support Systems: Office Automation Systems, Decision Support Systems, Types of DSS
  11. Data Mart: Online Analytical Processing (OLAP), Types of Models Used in DSS
  12. Organizational Information Systems, Marketing Information Systems, Key CRM Tasks
  13. Manufacturing Information System, Inventory Sub System, Production Sub System, Quality Sub system
  14. Accounting & Financial Information Systems, Human Resource Information Systems
  15. Decision Making: Types of Problems, Type of Decisions
  16. Phases of decision-making: Intelligence Phase, Design Phase, Choice Phase, Implementation Phase
  17. Planning for System Development: Models Used for and Types of System Development Life-Cycle
  18. Project lifecycle vs. SDLC, Costs of Proposed System, Classic lifecycle Model
  19. Entity Relationship Diagram (ERD), Design of the information flow, data base, User Interface
  20. Incremental Model: Evaluation, Incremental vs. Iterative
  21. Spiral Model: Determine Objectives, Alternatives and Constraints, Prototyping
  22. System Analysis: Systems Analyst, System Design, Designing user interface
  23. System Analysis & Design Methods, Structured Analysis and Design, Flow Chart
  24. Symbols used for flow charts: Good Practices, Data Flow Diagram
  25. Rules for DFDs: Entity Relationship Diagram
  26. Symbols: Object-Orientation, Object Oriented Analysis
  27. Object Oriented Analysis and Design: Object, Classes, Inheritance, Encapsulation, Polymorphism
  28. Critical Success Factors (CSF): CSF vs. Key Performance Indicator, Centralized vs. Distributed Processing
  29. Security of Information System: Security Issues, Objective, Scope, Policy, Program
  30. Threat Identification: Types of Threats, Control Analysis, Impact analysis, Occurrence of threat
  31. Control Adjustment: cost effective Security, Roles & Responsibility, Report Preparation
  32. Physical vs. Logical access, Viruses, Sources of Transmissions, Technical controls
  33. Antivirus software: Scanners, Active monitors, Behavior blockers, Logical intrusion, Best Password practices, Firewall
  34. Types of Controls: Access Controls, Cryptography, Biometrics
  35. Audit trails and logs: Audit trails and types of errors, IS audit, Parameters of IS audit
  36. Risk Management: Phases, focal Point, System Characterization, Vulnerability Assessment
  37. Control Analysis: Likelihood Determination, Impact Analysis, Risk Determination, Results Documentation
  38. Risk Management: Business Continuity Planning, Components, Phases of BCP, Business Impact Analysis (BIA)
  39. Web Security: Passive attacks, Active Attacks, Methods to avoid internet attacks
  40. Internet Security Controls, Firewall Security SystemsIntrusion Detection Systems, Components of IDS, Digital Certificates
  41. Commerce vs. E-Business, Business to Consumer (B2C), Electronic Data Interchange (EDI), E-Government
  42. Supply Chain Management: Integrating systems, Methods, Using SCM Software
  43. Using ERP Software, Evolution of ERP, Business Objectives and IT
  44. ERP & E-commerce, ERP & CRM, ERP Ownership and sponsor ship
  45. Ethics in IS: Threats to Privacy, Electronic Surveillance, Data Profiling, TRIPS, Workplace Monitoring