SHAP: Suppressing the Detection of Inconsistency Hazards by Pattern Learning

Context-aware applications rely on contexts derived from sensory data to adapt their behavior. However, contexts can be inconsistent and cause application anomaly or crash. One popular solution is to detect and resolve context inconsistencies at runtime. However, we observe that many detected inconsistencies do not indicate real context problems. Instead, they are caused by improper inconsistency detection. These inconsistencies are harmless, and their resolution is unnecessary or may even cause new problems. We name them inconsistency hazards. Inconsistency hazards should be suppressed, but their occurrences resemble normal inconsistencies. In this paper, we present a pattern-learning based approach SHAP to suppressing the detection of inconsistency hazards. Our key insight is that the detection of such hazards is subject to certain patterns of context changes. These patterns, although difficult to specify manually, can be learned effectively from historical inconsistency detection data. We evaluated our SHAP experimentally through three context-aware applications. The results reported that SHAP can automatically suppress the detection of over 90% inconsistency hazards, while preserving the detection of over 98% normal inconsistencies, with only negligible overhead.