The evaluation of network operation and maintenance quality is an important reference for carriers to improve their service. However, the traditional evaluation methods involve so much human participation that it cannot cope with the explosive amount of data. Therefore, both the major carriers and researchers are trying to find solutions to evaluate the quality of network operation and maintenance more objectively and accurately. In this paper, we analyze the general process of quality evaluation models for network operation and maintenance. The process has four steps: 1) selection of evaluation indicators; 2) data process for chosen indicators; 3) determination of indicator weights; 4) establishment of evaluation models. We further describe the working principle of each step, especially the methods for indicator selection and weight determination. Finally, we review the recently proposed evaluation models and the international standards of network operation and maintenance quality evaluation.

Managing largescale complex network infrastructures is challenging due to the huge number of heterogeneous network elements. The goal of this survey is to provide an overview of event mining techniques applied in the network management domain. Event mining includes a series of techniques for automatically and effectively discovering valuable knowledge from historical event/log data. We present three research challenges (i.e., event generation, root cause analysis, and failure prediction) for event mining in network management and introduce the corresponding solutions. Event generation (i.e., converting messages in log files into structured events) is the first step in many event mining applications. Automatic root cause analysis can locate the faulty elements/components without the help of experienced domain experts. Failure prediction in proactive fault management improves network reliability. The representative studies to address the three aforementioned challenges are reviewed and their main ideas are summarized in the survey. In addition, our survey shows that using event mining techniques can improve the network management efficiency and reduce the management cost.