A Web-based Intelligent Hybrid System for Fault Diagnosis Gunjan Jha Research Student Nanyang Technological University Singapore

3/23/99AAAI, SSS-'992 Presentation Overview Traditional Hotline Service Support Related Work & Techniques The WebService System Customer Service Database The Hybrid Approach Summary & Conclusion

3/23/99AAAI, SSS-'993 Traditional Hotline Service Support Customers located worldwide make long distance calls to the service centre The service engineer provides an advice to the customer by referring to the Customer Service Database (Knowledge Base) The service engineer may need to pay an onsite visit if the advice does not work

3/23/99AAAI, SSS-'994 Traditional Hotline Service Support

3/23/99AAAI, SSS-'995 Disadvantages of the traditional customer support process Expensive overseas telephone calls Expensive onsite trips by service engineers The need to train and maintain experienced service engineer Dependence on the service engineers and the customer service database

3/23/99AAAI, SSS-'996 Online Customer Service Support BBS (Bulletin Board System) ARWeb, Cognitive , Target WebLink and ClearExpress WebSupport [Muller 96] Muller, N.J., Expanding the Help Desk through the World Wide Web. Information Systems Management, 13(3): Compaq, NEC [Chang 1996] K. H. Chang, et al., A Self-Improving Helpdesk Service System Using Case-Based Reasoning Techniques. Computers in Industry, 30(2):

3/23/99AAAI, SSS-'997 The WebService System

3/23/99AAAI, SSS-'998 Customer Service Record Database A fault record consists of –fault condition –checkpoints Example Fault Condition: CASSETTE DETECTION ERROR. Checkpoints: (1) IS THE CASSETTE 'SITTING' PROPERLY. (2) ENSURE THAT THE TAPE GUIDE IS PROPERLY SET. (3) CONFIRM THE OPTICAL MODULE. (T.G. PG. 10).

3/23/99AAAI, SSS-'999 Intelligent Fault Diagnosis Techniques Case based reasoning (most popular) Artificial neural network (Learning Systems) Rule based reasoning (for Quasi-static systems) Miscellaneous techniques Fuzzy logic, Genetic algorithms, Decision trees and Statistical techniques Hybrid techniques

3/23/99AAAI, SSS-'9910 The Hybrid Approach Based on hybrid CBR-ANN-RBR approach Integrate Neural Network into the CBR cycle for indexing, retrieval and learning Use Rule-based reasoning for Case-Reuse and assistance in carrying out the diagnosis Major tasks: –Knowledge Acquisition, Retrieval, Reuse, Revise and Retain

3/23/99AAAI, SSS-'9911 Fault Diagnosis Process

3/23/99AAAI, SSS-'9912 Knowledge Acquisition

3/23/99AAAI, SSS-'9913 Forming a Weight Vector

3/23/99AAAI, SSS-'9914 Checkpoint Rule for a Fault- condition

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3/23/99AAAI, SSS-'9919 Reuse of Checkpoint Solution

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3/23/99AAAI, SSS-'9921 Case Retain or Maintenance Module

3/23/99AAAI, SSS-'9922 Summary The research has successfully demonstrated the effectiveness of hybrid CBR-ANN-RBR approach for the fault diagnosis problem Performance analysis have proved the approach to be much accurate and efficient than the traditional CBR techniques (Nearest Neighbor) Future work focuses on incorporating genetic algorithm and data mining techniques for better accuracy and efficiency

3/23/99AAAI, SSS-'9923 Performance Analysis Performance compared with traditional CBR systems using kNN technique Retrieval Accuracy: test data from customer service database (size ~ 15000) –ANN: 93.2% –kNN1: 76.7% (Fuzzy Trigram) –kNN2: 81.4% (Euclidean distance based matching)

3/23/99AAAI, SSS-'9924 Performance Analysis (…continued) Retrieval Accuracy: test data from the user input (size = 50) –ANN: 88% –kNN1: 78% (Fuzzy Trigram) –kNN2: 72% (Euclidean distance based matching) Average Retrieval Speed (test size ~ 15000) –ANN: 1.9s –kNN1: 12.3s –kNN2: 9.6s

3/23/99AAAI, SSS-' possible methods to Update Checkpoint-Rule Priority Method 1: No need to change the priorities of checkpoints. Method 2: Assign priority “1” to the checkpoint that solves the problem and decrease the priorities of the checkpoints ahead of it by “1”. Method 3: Swap the priority of the checkpoint that solves the problem with the one just ahead of it.

3/23/99AAAI, SSS-'9926 Performance comparison of three methods to update checkpoint priorities.