Handling Missing Syndromes

The diagnosis accuracy of reasoning-based diagnosis engine may be significantly reduced when the repair logs are fragmented and some errors, or syndromes, are not available during diagnosis. Since root-cause isolation for a failing board relies on reasoning based on syndromes, any information loss (e.g., missing syndromes) during the extraction of a diagnosis log may lead to ambiguous repair suggestions. In this chapter, we propose a board-level diagnosis system with the feature of handling missing syndromes using the method of imputation. The syndromes from a faulty-board log are analyzed and imputed with appropriate values in a preprocessing engine before root-cause isolation. We utilize several imputation methods and compare them in terms of their effectiveness in handling missing syndromes.