To identify the cause of the error and maintain the health of system, an administrator usually analyzes event log data since it contains useful information to infer the cause of the error. However, because today’s systems are huge and complex, it is almost impossible for administrators to manually analyze event log files to identify the cause of an error. In particular, as OpenStack, which is being widely used as cloud management system, operates with various service modules being linked to multiple servers, it is hard to access each node and analyze event log messages for each service module in the case of an error. For this, in this paper, we propose a novel message-based log analysis method that enables the administrator to find the cause of an error quickly. Specifically, the proposed method 1) consolidates event log data generated from system level and application service level, 2) clusters the consolidated data based on messages, and 3) analyzes interrelations among message groups in order to promptly identify the cause of a system error. This study has great significance in the following three aspects. First, the root cause of the error can be identified by collecting event logs of both system level and application service level and analyzing interrelations among the logs. Second, administrators do not need to classify messages for training since unsupervised learning of event log messages is applied. Third, using Dynamic Time Warping, an algorithm for measuring similarity of dynamic patterns over time increases accuracy of analysis on patterns generated from distributed system in which time synchronization is not exactly consistent.

There has been a huge progress in semiconductor manufacturing processes such as reduction of the design rule(DR) and development of multi-processes. And, semiconductor industries have steadily extended its business and market share by reducing the design rule(DR) and enlarging the wafer size as well as by resolving many difficult technical problems through various noble approaches in order to reduce the production cost and to improve the yield. In semiconductor manufacturing, there is a significant difference in the number of memory chips produced according to the wafer size, wafer yield, and the level of the design rule even though the same number of wafers were put to the manufacturing process. So, almost all semiconductor manufacturing companies reach the conclusion that the enlarged size of wafer should be adopted in order to enhance the productivity and reduce the production cost. Thus, in this study, we investigate the specifications of the key functions and capabilities of the necessary modules in the yield analysis and improvement system required to acquire the stationary wafer yield with considering the 450mm wafer manufacturing system. Then the results of this research will be helpful for constructing the advanced yield analysis and improvement system called Real-Time Fault Monitoring and Detection (RTFMD) system.

The widespread sensors in a structural monitoring system provide vital support to its operation. Data is obtainedf rom sensors in a structural health monitoring system for integrity assessment of the structure, and false alarm will be frequently triggered if a faulty sensor is detected. In this study, a proposed method based on machine learning algorithm and Gaussian distribution is present to identify sensor fault.