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CHAPTER 7&8 Knowledge-Based Decision Support: Artificial Intelligence and Expert Systems 1 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Knowledge-Based Decision Support: Artificial Intelligence and Expert Systems n n n n Managerial Decision Makers are Knowledge Workers Use Knowledge in Decision Making Accessibility to Knowledge Issue Knowledge-Based Decision Support: Applied Artificial Intelligence 2 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ AI Concepts and Definitions n n n Many Definitions AI Involves Studying Human Thought Processes Representing Thought Processes on Machines 3 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Artificial Intelligence n n n Behavior by a machine that, if performed by a human being, would be considered intelligent “…study of how to make computers do things at which, at the moment, people are better” (Rich and Knight [1991]) Theory of how the human mind works (Mark Fox) 4 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ AI Objectives n n n Make machines smarter (primary goal) Understand what intelligence is (Nobel Laureate purpose) Make machines more useful (entrepreneurial purpose) (Winston and Prendergast [1984]) 5 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Signs of Intelligence n n n n Learn or understand from experience Make sense out of ambiguous or contradictory messages Respond quickly and successfully to new situations Use reasoning to solve problems 6 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ More Signs of Intelligence n n n n n Deal with perplexing situations Understand and infer in ordinary, rational ways Apply knowledge to manipulate the environment Think and reason Recognize the relative importance of different elements in a situation 7 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Turing Test for Intelligence A computer can be considered to be smart only when a human interviewer, “conversing” with both an unseen human being and an unseen computer, can not determine which is which 8 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ AI Represents Knowledge as Sets of Symbols A symbol is a string of characters that stands for some real-world concept Examples n n n n Product Defendant 0.8 Chocolate Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ 9 Symbol Structures (Relationships) n n n n (DEFECTIVE product) (LEASED-BY product defendant) (EQUAL (LIABILITY defendant) 0.8) tastes_good (chocolate). 10 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ n AI Programs Manipulate Symbols to Solve Problems n Symbols and Symbol Structures Form Knowledge Representation n Artificial Intelligence Dealings Primarily with Symbolic, Nonalgorithmic Problem-Solving Methods 11 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Characteristics of Artificial Intelligence n n Numeric versus Symbolic Algorithmic versus Nonalgorithmic 12 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Heuristic Methods for Processing Information n n Search Inferencing “AI is the branch of computer science that deals with ways of representing knowledge using symbols rather than numbers and with rules-ofthumb, or heuristic, methods for processing information”. 13 AI Advantages Over Natural Intelligence n n n n n n n More permanent Ease of duplication and dissemination Less expensive Consistent and thorough Can be documented Can execute certain tasks much faster than a human can Can perform certain tasks better than many or even most people 14 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Natural Intelligence Advantages over AI n n n Natural intelligence is creative People use sensory experience directly Can use a wide context of experience in different situations AI - Very Narrow Focus 15 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Knowledge in Artificial Intelligence Knowledge encompasses the implicit and explicit restrictions placed upon objects (entities), operations, and relationships along with general and specific heuristics and inference procedures involved in the situation being modeled Of data, information, and knowledge, KNOWLEDGE is most abstract and in the smallest quantity 16 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ Uses of Knowledge n n n n n Knowledge consists of facts, concepts, theories, heuristic methods, procedures, and relationships Knowledge is also information organized and analyzed for understanding and applicable to problem solving or decision making Knowledge base - the collection of knowledge related to a problem (or opportunity) used in an AI system Typically limited in some specific, usually narrow, subject area or domain The narrow domain of knowledge, and that an AI system must involve some qualitative aspects of decision making (critical for AI application success) 17 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ Knowledge Bases n n n Search the Knowledge Base for Relevant Facts and Relationships Reach One or More Alternative Solutions to a Problem Augments the User (Typically a Novice) 18 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ How Artificial Intelligence Differs from Conventional Computing 19 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ Conventional Computing n n n n n Based on an Algorithm (clearly defined, step-by-step procedure) Mathematical Formula or Sequential Procedure Converted into a Computer Program Uses Data (Numbers, Letters, Words) Limited to Very Structured, Quantitative Applications (Table 10.1) 20 Table 10.1: How Conventional Computers Process Data n n n n n n n n n n Calculate Perform Logic Store Retrieve Translate Sort Edit Make Structured Decisions Monitor Control 21 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ AI Computing n n n n Based on symbolic representation and manipulation A symbol is a letter, word, or number represents objects, processes, and their relationships Objects can be people, things, ideas, concepts, events, or statements of fact Create a symbolic knowledge base 22 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ AI Computing (cont’d) n n n Uses various processes to manipulate the symbols to generate advice or a recommendation AI reasons or infers with the knowledge base by search and pattern matching Hunts for answers (Algorithms often used in search) 23 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ AI Computing (cont’d) n Caution: AI is NOT magic n AI is a unique approach to programming computers (Table 6.2) 24 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ Table 6.2: Artificial Intelligence vs. Conventional Programming Dimension Processing Nature of Input Search Explanation Major Interest Structure Artificial Intelligence Primarily Symbolic Can be Incomplete Heuristic (Mostly) Provided Knowledge Separation of Control from Knowledge Nature of Output Can be Incomplete Maintenance and Easy Because of Update Modularity Hardware Mainly Workstations and Personal Computers Reasoning Limited, but Improving Capability Conventional Programming Primarily Algorithmic Must be Complete Algorithms Usually Not Provided Data, Information Control Integrated with Information (Data) Must be Correct Usually Difficult All Types None 25 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson Copyright 1998, Prentice Hall, Upper Saddle River, NJ Major AI Areas n n n n n n n Expert Systems Natural Language Processing Speech Understanding Robotics and Sensory Systems Computer Vision and Scene Recognition Intelligent Computer-Aided Instruction Neural Computing Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ 26 Additional AI Areas n n n n n News Summarization Language Translation Fuzzy Logic Genetic Algorithms Intelligent Software Agents 27 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ An Expert System Solution General Electric's (GE) : Top Locomotive Field Service Engineer was Nearing Retirement Traditional Solution: Apprenticeship but would like n A more effective and dependable way to disseminate expertise n To prevent valuable knowledge from retiring n To minimize extensive travel or moving the locomotives n n To MODEL the way a human troubleshooter works – Months of knowledge acquisition – 3 years of prototyping A novice engineer or technician can perform at an expert’s level – On a personal computer – Installed at every railroad repair shop served by GE 3 28 (ES) Introduction n n n Expert System vs. knowledge-based system An Expert System is a system that employs human knowledge captured in a computer to solve problems that ordinarily require human expertise ES imitate the expert’s reasoning processes to solve specific problems 4 29 History of Expert Systems 1. Early to Mid-1960s – n n One attempt: the General-purpose Problem Solver (GPS) General-purpose Problem Solver (GPS) A procedure developed by Newell and Simon [1973] from their Logic Theory Machine – Attempted to create an "intelligent" computer • – – general problem-solving methods applicable across domains Predecessor to ES Not successful, but a good start 5 30 2. Mid-1960s: Special-purpose ES programs – – n DENDRAL MYCIN Researchers recognized that the problemsolving mechanism is only a small part of a complete, intelligent computer system – – – – General problem solvers cannot be used to build high performance ES Human problem solvers are good only if they operate in a very narrow domain Expert systems must be constantly updated with new information The complexity of problems requires a considerable amount of knowledge about the problem area 6 31 3. Mid 1970s – – – Several Real Expert Systems Emerge Recognition of the Central Role of Knowledge AI Scientists Develop • • n Comprehensive knowledge representation theories General-purpose, decision-making procedures and inferences Limited Success Because – – Knowledge is Too Broad and Diverse Efforts to Solve Fairly General KnowledgeBased Problems were Premature 7 32 BUT n Several knowledge representations worked Key Insight n The power of an ES is derived from the specific knowledge it possesses, not from the particular formalisms and inference schemes it employs 8 33 4. Early 1980s n ES Technology Starts to go Commercial – – – n Programming Tools and Shells Appear – – – – n XCON XSEL CATS-1 EMYCIN EXPERT META-DENDRAL EURISKO About 1/3 of These Systems Are Very Successful and Are Still in Use 9 34 Latest ES Developments n n n n n Many tools to expedite the construction of ES at a reduced cost Dissemination of ES in thousands of organizations Extensive integration of ES with other CBIS Increased use of expert systems in many tasks Use of ES technology to expedite IS construction (ES Shell) 10 35 n n n n n n The object-oriented programming approach in knowledge representation Complex systems with multiple knowledge sources, multiple lines of reasoning, and fuzzy information Use of multiple knowledge bases Improvements in knowledge acquisition Larger storage and faster processing computers The Internet to disseminate software and expertise. 11 36 Expert Systems n n n Attempt to Imitate Expert Reasoning Processes and Knowledge in Solving Specific Problems Most Popular Applied AI Technology – Enhance Productivity – Augment Work Forces Narrow Problem-Solving Areas or Tasks 37 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expert Systems n Provide Direct Application of Expertise n Expert Systems Do Not Replace Experts, But They – Make their Knowledge and Experience More Widely Available – Permit Nonexperts to Work Better 38 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expert Systems n n n n n Expertise Transferring Experts Inferencing Rules Explanation Capability 39 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expertise n n The extensive, task-specific knowledge acquired from training, reading and experience – Theories about the problem area – Hard-and-fast rules and procedures – Rules (heuristics) – Global strategies – Meta-knowledge (knowledge about knowledge) – Facts Enables experts to be better and faster than nonexperts Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ 40 Human Expert Behaviors n n n n n n n n Recognize and formulate the problem Solve problems quickly and properly Explain the solution Learn from experience Restructure knowledge Break rules Determine relevance Degrade gracefully 41 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Human Experts n Knowledge acquisition from human experts the “paradox of expertise” 17 42 Transferring Expertise n n n Objective of an expert system – To transfer expertise from an expert to a computer system and – Then on to other humans (nonexperts) Activities – Knowledge acquisition – Knowledge representation – Knowledge inferencing – Knowledge transfer to the user Knowledge is stored in a knowledge base 43 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Two Knowledge Types n n Facts Procedures (usually rules) Regarding the Problem Domain 44 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Inferencing n n n Reasoning (Thinking) The computer is programmed so that it can make inferences Performed by the Inference Engine 45 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Rules n IF-THEN-ELSE n Explanation Capability – By the justifier, or explanation subsystem ES versus Conventional Systems n 46 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Knowledge as Rules n MYCIN rule example: IF the infection is meningitis AND patient has evidence of serious skin or soft tissue infection AND organisms were not seen on the stain of the culture AND type of infection is bacterial THEN There is evidence that the organism (other than those seen on cultures or smears) causin the infection is Staphylococus coagpus. 22 47 Structure of Expert Systems n n Development Environment Consultation (Runtime) Environment 48 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Three Major ES Components User Interface Inference Engine Knowledge Base 49 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ ES Shell Working Memory User Interface Inference Engine Knowledge Base Explanation Facility Database, Spreadsheets, etc. Knowledge Acquisition Basic ES Structure 26 50 All ES Components n n n n n n n n n Knowledge Acquisition Subsystem Knowledge Base Inference Engine User Interface Blackboard (Workplace) Explanation Subsystem (Justifier) Knowledge Refining System User Most ES do not have a Knowledge Refinement Component (See Figure 10.3) 51 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Knowledge Base n The knowledge base contains the knowledge necessary for understanding, formulating, and solving problems n Two Basic Knowledge Base Elements – Facts – Special heuristics, or rules that direct the use of knowledge – Knowledge is the primary raw material of ES – Incorporated knowledge representation Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ 52 Inference Engine n n n The brain of the ES The control structure (rule interpreter) Provides methodology for reasoning 53 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ User Interface n n Language processor for friendly, problem-oriented communication NLP, or menus and graphics 54 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ The Human Element in Expert Systems n Builder and User Expert and Knowledge engineer. n The Expert n – – Has the special knowledge, judgment, experience and methods to give advice and solve problems Provides knowledge about task performance 35 55 The Knowledge Engineer n n Helps the expert(s) structure the problem area by interpreting and integrating human answers to questions, drawing analogies, posing counterexamples, and bringing to light conceptual difficulties Usually also the System Builder 36 56 The User n Possible Classes of Users – – – – n A non-expert client seeking direct advice the ES acts as a Consultant or Advisor A student who wants to learn - an Instructor An ES builder improving or increasing the knowledge base - a Partner An expert - a Colleague or Assistant The Expert and the Knowledge Engineer Should Anticipate Users' Needs and Limitations When Designing ES 37 57 How Expert Systems Work Major Activities of ES Construction and Use n n n Development Consultation Improvement 58 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ ES Development n n Construction of the knowledge base Knowledge separated into – – n n Declarative (factual) knowledge and Procedural knowledge Construction (or acquisition) of an inference engine, a blackboard, an explanation facility, and any other software Determine appropriate knowledge representations 40 59 ES Shell n n Includes All Generic ES Components But No Knowledge – EMYCIN from MYCIN – (E=Empty) 60 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expert Systems Shells Software Development Packages n n n n Exsys InstantTea K-Vision KnowledgePro 61 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Problem Areas Addressed by Expert Systems n n n n n n n n n n Interpretation systems Prediction systems Diagnostic systems Design systems Planning systems Monitoring systems Debugging systems Repair systems Instruction systems Control systems 62 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expert Systems Benefits n n n n n n n n n n Improved Decision Quality Increased Output and Productivity Decreased Decision Making Time Increased Process(es) and Product Quality Capture Scarce Expertise Can Work with Incomplete or Uncertain Information Enhancement of Problem Solving and Decision Making Improved Decision Making Processes Knowledge Transfer to Remote Locations Enhancement of Other MIS Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ 63 Lead to n Improved decision making Improved products and customer service Sustainable strategic advantage n May enhance organization’s image n n 64 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Problems and Limitations of Expert Systems n n n n n n n Knowledge is not always readily available Expertise can be hard to extract from humans Expert system users have natural cognitive limits ES work well only in a narrow domain of knowledge Knowledge engineers are rare and expensive Lack of trust by end-users ES may not be able to arrive at valid conclusions 65 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expert System Success Factors n n Most Critical Factors – Champion in Management – User Involvement and Training Plus – The level of knowledge must be sufficiently high – There must be (at least) one cooperative expert – The problem must be qualitative (fuzzy), not quantitative – The problem must be sufficiently narrow in scope – The ES shell must be high quality, and naturally store and manipulate the knowledge – A friendly user interface 66 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson – Important and difficult enough problem 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ For Success 1. Business applications justified by strategic impact (competitive advantage) 2. Well-defined and structured applications 67 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ Expert Systems Types n n n n n n n Expert Systems Versus Knowledgebased Systems Rule-based Expert Systems Frame-based Systems Hybrid Systems Model-based Systems Ready-made (Off-the-Shelf) Systems Real-time Expert Systems 68 Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ ES on the Web n n n n n Provide knowledge and advice Help desks Knowledge acquisition Spread of multimedia-based expert systems (Intelimedia systems) Support ES and other AI technologies provided to the Internet/Intranet Decision Support Systems and Intelligent Systems, Efraim Turban and Jay E. Aronson 6th ed, Copyright 2001, Prentice Hall, Upper Saddle River, NJ 69