Introduction to Knowledge Engineering What is Knowledge Engineering

Introduction to Knowledge Engineering What is Knowledge Engineering? History & Terminology Introduction

Data, information & knowledge n Data ä “raw signals”. . . ---. . . n Information ä meaning attached to data S O S n Knowledge ä ä attach purpose and competence to information potential to generate action emergency alert ® start rescue operation Introduction 2

Knowledge engineering process of ä ä eliciting, structuring, formalizing, operationalizing information and knowledge involved in a knowledgeintensive problem domain, in order to construct a program that can perform a difficult task adequately Introduction 3

Problems in knowledge engineering n n n complex information and knowledge is difficult to observe experts and other sources differ multiple representations: ä ä Introduction textbooks graphical representations heuristics skills 4

A Short History of Knowledge Systems Introduction 5

Methodological pyramid Introduction 6

World view: Model-Based KE n n n The knowledge-engineering space of choices and tools can to some extent be controlled by the introduction of a number of models Each model emphasizes certain aspects of the system to be built and abstracts from others. Models provide a decomposition of knowledgeengineering tasks: while building one model, the knowledge engineer can temporarily neglect certain other aspects. Introduction 7

Common. KADS principles n n n Knowledge engineering is not some kind of `mining from the expert's head', but consists of constructing different aspect models of human knowledge The knowledge-level principle: in knowledge modeling, first concentrate on the conceptual structure of knowledge, and leave the programming details for later Knowledge has a stable internal structure that is analyzable by distinguishing specific knowledge types and roles. Introduction 8

Common. KADS theory n n KBS construction entails the construction of a number of models that together constitute part of the product delivered by the project. Supplies the KBS developer with a set of model templates. This template structure can be configured, refined and filled during project work. The number and level of elaboration of models depends on the specific project context. Introduction 9

Common. KADS Model Set Context Concept Artefact Introduction Organization Model Task Model Knowledge Model Agent Model Communication Model Design Model 10

Model Set Overview (1) n Organization model ä ä n Task model ä n describes tasks that are performed or will be performed in the organizational environment Agent model ä Introduction supports analysis of an organization, Goal: discover problems, opportunities and possible impacts of KBS development. describes capabilities, norms, preferences and permissions of agents (agent = executor of task). 11

Model Set Overview (2) n Knowledge model ä n Communication model ä n gives an implementation-independent description of knowledge involved in a task. models the communicative transactions between agents. Design model ä Introduction describes the structure of the system that needs to be constructed. 12

Principles of the Model Set n n n Divide and conquer. Configuration of an adequate model set for a specific application. Models evolve through well defined states. The model set supports project management. Model development is driven by project objectives and risk. Models can be developed in parallel. Introduction 13

Models exist in various forms n Model template ä n Model instance ä n objects manipulated during a project. Model versions ä n predefined, fixed structure, can be configured versions of a model instance can exist. Multiple model instances ä ä Introduction separate instances can be developed example: ''current'' and ''future'' organization 14

The Product n Instantiated models ä n Additional documentation ä n represent the important aspects of the environment and the delivered knowledge based system. information not represented in the filled model templates (e. g. project management information) Software ä ä Introduction Common. KADS Tools Protégé 15

Terminology n Domain ä some area of interest banking, food industry, photocopiers, car manufacturing n Task ä something that needs to be done by an agent monitor a process; create a plan; analyze deviant behavior n Agent ä the executor of a task in a domain typically either a human or some software system Introduction 16

Terminology n Application ä n Application domain ä n The context provided by the combination of a task and a domain in which this task is carried out by agents The particular area of interest involved in an application Application task ä Introduction The (top-level) task that needs to be performed in a certain application 17