Detecting Application-Level Failures in Component-based Internet Services

etc.) suffer faults. Quickly detecting these faults can be the largest bottleneck in improving availability of the system. We present Pinpoint, a methodology for automating fault detection in Internet services by (1) observing low-level, internal structural behaviors of the service; (2) modeling the majority behavior of the system as correct; and (3) detecting anomalies in these behaviors as possible symptoms of failures. Without requiring any a priori application-specific information, Pinpoint correctly detected 89– 96 % of major failures in our experiments, as compared with 20–70 % detected by current application-generic techniques. Index Terms — Internet services, application-level failures, anomaly detection I

Improving The Effectiveness Of Web

Perusal of textual displays of document surrogates produced by Web-based rankedoutput retrieval services may require much user time, effort, and money. In this paper we present VIEWER, a graphical interface that allows visualization and manipulation of views of retrieval results, where a view is the subset of retrieved surrogates that contain a specified subset of query terms. We argue that VIEWER helps the user focus on relevant parts of the results and, in addition, it may facilitate query reformulation. We present the results of an experiment performed by six subjects on two medium size bibliographical test collections in which VIEWER, used as an interactive ranking systems, outperformed both best match ranking and coordination level-based ranking