On a Multimode Test Sequencing Problem

Abstract

Test sequencing is a binary identification problem wherein one needs to develop a minimal expected cost test procedure to determine which one of a finite number of possible failure states, if any, is present. In this paper, we consider a multimode test sequencing (MMTS) problem, in which tests are distributed among multiple modes and additional transition costs will be incurred if a test sequence involves mode changes. The multimode test sequencing problem can be solved optimally via dynamic programming or AND/OR graph search methods. However, for large systems, the associated computation with dynamic programming or AND/OR graph search methods is substantial due to the rapidly increasing number of OR nodes (denoting ambiguity states and current modes) and AND nodes (denoting next modes and tests) in the search graph. In order to overcome the computational explosion, we propose to apply three heuristic algorithms based on information gain: information gain heuristic (IG), mode capability evaluation (MC), and mode capability evaluation with limited exploration of depth and degree of mode Isolation (MCLEI). We also propose to apply rollout strategies, which are guaranteed to improve the performance of heuristics, as long as the heuristics are sequentially improving. We show computational results, which suggest that the information-heuristic based rollout policies are significantly better than traditional information gain heuristic. We also show that among the three information heuristics proposed, MCLEI achieves the best tradeoff between optimality and computational complexity.

Computer Vision-Guided Virtual Craniofacial Surgery

“…Note that 3D jigsaw puzzle solving is an example of a computationally intractable NP-hard problem in the area of computer vision and pattern recognition. Some other problems in the same category include planar shape prototype generation as discussed by Chen et al [99], minimum distance problems with convex or concave bodies as described by Carreto and Nihan [100] and the multimode test sequencing problem discussed by Ruan et al [101].…”

Dynamic Multiple-Fault Diagnosis With Imperfect Tests

“…Thus, the problem is one of determining the fault states of components, given a set of partial and unreliable test outcomes over time. Consequently, diagnostic logic that hedges against this uncertainty in test outcomes is of significant interest to the diagnostic community [15], [18], [2], [14], [11].…”

“…Previous research on system fault diagnosis has focused on test sequencing problems for single fault diagnosis [15], [17] and its variants [20], [18], test sequencing for multiple fault diagnosis [19], and the "static" multiple fault diagnosis [19], [21], [24], [25], [12] of identifying the set of most probable fault states given a set of test outcomes. Dynamic single fault diagnosis problem was first proposed by Ying et al [23], where it is assumed that, at any time, the system has at most one fault state present.…”

Research on optimal method for fault maintenance strategy based on AND/OR graph searching

“…Basically, the algorithms used for a binary test system can be applied to multi-valued test systems. The differences only reside in the generation of F-lists, which needs large preprocess for the matrix transformation [7,8]. In this paper, we combine the efficiency function in noiseless diagnosis and multisource Huffman coding in information theory with the AND/OR graph search to obtain improved solutions straightly.…”