Lifecycles and Methodologies

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Lifecycles and Methodologies

• Contents
• We will be looking at 3 specific methodologies.
  These are -
• Blackboard Architectures
• KADS (Knowledge Acquisition Design Strategy)
• HYM
• Also, some recent work in defining ontologies

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Lifecycles and Methodologies
Analysis
Design
Implementation
Validation
Quality Assurance
Installation
Project Management
Use of Standards
Maintenance
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Lifecycles and Methodologies

• An incremental prototyping approach for large or
  complex systems.

Design Prototype
Identify Requirements
Implement Prototype
Evaluate
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Lifecycles and Methodologies

• Advantages of using an incremental prototyping
  approach -
• Allows the accuracy of the knowledge base to be
  demonstrated during iterations of the lifecycle
• The quality of the reasoning is open to
  inspection
• It provides an easy mechanism to involve the
  users, management and experts
• It allows the project to be signed off as complete

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Lifecycles and Methodologies

• Disadvantages of using an incremental prototyping
  approach -
• The ability to develop small projects does not
  always mean that it is possible to develop and
  maintain large real-world systems
• Difficult to define the cost and timetables

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Lifecycles and Methodologies

• Blackboard Architectures
• Provide a problem solving model for organising
  knowledge
• Provide a potential strategy for applying the
  knowledge
• Allow a range of knowledge representation methods
  to be applied
• Segment the knowledge base, making it more
  maintainable and the implementation more efficient

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Lifecycles and Methodologies

• Blackboard Architectures

Knowledge Sources
Blackboard
Working Memory
KB
IE
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Lifecycles and Methodologies

• A KBS System to Design a House
• A KBS to design the general layout of the house,
  grounds and paths
• A KBS that, given the layout, will design the
  gardens
• A KBS that, given the layout, will design the
  internal structure of the house, allocate rooms,
  set room sizes, specify doors and windows etc.
• A KBS that, given specific room details, will
  design the kitchen
• Etc. etc.

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Lifecycles and Methodologies
Blackboard
Knowledge sources
KBS to design general layout of the house and
grounds
General layout gardens
KBS to design the gardens
House structure
Kitchen
KBS to design the internal house structure
Dining room
Living room
KBS to design the kitchen
Etc. etc.
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Lifecycles and Methodologies

• Knowledge Acquisition as a Modeling Exercise
• The reasoning processes, the domain knowledge and
  the behaviour of an organisation can be modeled
  separately
• Modeling the problem solving behaviour of experts
  can help to develop problem solving methods for
  generic tasks

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Lifecycles and Methodologies

• Problem Solving Methods - Advantages
• Problem solving methods for solving the same
  generic task can be compared
• The problem solving method is open to inspection,
  and can be improved without affecting the domain
  knowledge
• Separating the problem solving method from the
  domain knowledge enables re-use i.e. separating
  control and domain knowledge.
• (e.g. The general process of designing a car may
  be very similar to that employed to design a
  house)

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Lifecycles and Methodologies

• PSMs - Complexities
• To enable reuse we need to develop a library of
  PSMs. However PSMs are difficult to classify. We
  need to specify the genericness (task
  independence) and granularity (size).
• Reusability - Usability trade off to consider.
  Task independent PSMs will require refinement and
  adaptation before they can be used. They can
  however be reused in a range of situations. Task
  dependent PSMs require little adaptation before
  use, however they are less easily used elsewhere.
  

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Lifecycles and Methodologies

• KADS - (Knowledge Acquisition Design Strategy)
• Common KADS
• Analysis (stages)
• Process analysis
• Cooperation analysis
• Expertise analysis
• Constraint analysis
• Systems analysis
• Design (stages)
• Global design
• Knowledge based system design

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Lifecycles and Methodologies

• KADS - (Knowledge Acquisition Design Strategy)
• supports the development of various models
  including -
• The process or organisational model
• The expertise model
• MIKE(Model based Incremental Knowledge
  Engineering)
• Protégé II

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Lifecycles and Methodologies

• HYM is under development to support the creation
  of hybrid information systems
• It aims to provide an enhanced software
  development lifecycle that supports project
  development both incrementally and in one go
• It has a combined analysis and design phase that
  supports a smooth transition between the two
• The combined phase is highly iterative, and
  contains detailed design evaluation and quality
  assurance procedures
• It supports the seamless integration of KBS
  components with traditional IS components
• Supports integration of a number of methods to
  overcome the limitations of each

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Lifecycles and Methodologies
Hybrid information system level
Hybrid information system
Traditional system
Components level
Hybrid system
KBS
Repositories level
Databases
The HYM 3 layer architecture
Procedures
Knowledge
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Lifecycles and Methodologies

• Ontology - A study of things that exist
• In terms of a KBS, an ontology is used to define
  the objects, terms, and the knowledge that exists
  within that knowledge base