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Decision making with Case-Based Learning. Instructor Dr. George Collins By Ratna Prasad Kandi. Table of contents. Introduction Case based decision theory. Case analysis of CBDT Cognitive engine architecture Memory Forgetfulness
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Decision making with Case-Based Learning Instructor Dr. George Collins By Ratna Prasad Kandi
Table of contents • Introduction • Case based decision theory. • Case analysis of CBDT • Cognitive engine architecture • Memory • Forgetfulness • Cognitive engine CBDT implementation • Sensors • Conclusion
Introduction • In cognitive radio design, decision making is a complex part. • Cognitive radio adapts itself by making some decisions. • This decisions are based on user requirements or based on environmental and behavioral information. • Decisions based on the past knowledge.
Introduction • Same as how people solve problems. • Previous knowledge influences current decisions. • Anytime learningin changing problem spaces. • CBDT(case based decision theory).
Case based decision theory Uses sensors to observe when the environment or user needs change. New information is modeled as new problem to be solved by cognitive radio. Case based system analyzes the new problem against past cases in the memory. To determine the similarities between the new problem and past problems.
Case based decision theory Need to determine the utility of the past actions. Similarity function: • Defines how similar two cases are. • Measures how two cases are close i.e. ‘0’ represents no similarity and 1 represents perfect match. Utility function: How successful was an action responding to a problem.
Case analysis of CBDT • For a case based learning let set of problems be P, set of actions be A, set of results be R Then case C= P*A*R. • Decision is based on the function U(a)=s(p,q)u(r).
Cognitive Engine Architecture • The case base and optimization routers work together to enable learning and adaptation in cognitive engine. • The case base holds past cases, actions and results of the action. • The results are measurement of how well the action is performed.
Memory case base holds M cases. • It must have a system to delete or forget cases which are no longer used. • When cognitive engine observes a new case, either the new case is not remembered or it must replace current case. • To replace current cases we have forgetfulness functions.
Forgetfulness • Temporal forgetfulness: 1) In this method the oldest case is forgotten. 2) Simple to implement using FIFO buffer. Maximum distance forgetfulness: Two cases far away from each other are forgotten. Maximum utility forgetfulness: In this case with lowest utility is replaced by new case.
Cognitive engine CBDT Implementation • The new case is received by the cognitive controller through a sensor. • The cognitive controller calls the decision making process to find the information in the knowledge, or case ,base. • Then sends information to the optimizing routine for processing. • Each component can be developed and implemented independently.
Sensors • Cognitive Engine associates with three sensors to collect the meters, PSD and objectives. • The wireless system genetic algorithm does the optamization. • The PSD sensor provides an interference map that the GA uses in analyzing its objectives. • The case based decision maker uses the meters sensor in its utility calculations.
Example • Take the case of wireless communication standards. • Mobile phones provide different protocols like WiFi, Bluetooth, LTE, WiMax etc. • Based on the usage by the user wireless radios switch between different protocols. • The decision maker must be able to determine which service to use for current application.
Conclusion • Case based decision theory as the mechanism for providing the feedback. • When new problem is received ,the decision maker looks for similar problem in case base that exhibit high utility. • Utility function can have greater impact on the performance. • Case based learning provides significant potential for use with the cognitive engine where problem requires solutions quickly as situations and environment changes.
References Artificial Intelligence in Wireless Communications. Thomas Warren Rondeau, Charles W. Bostian. • I.Gilboa and D.Schmeidler, “ A Theory of case based Decisions”. • C.L Ramsey and J.J Grefenstette, “Case-based decisions” • D.E Goldberg, Genetic algorithm in search, optimization and machine learning.