Earticle

Spectrum-based Fault Localization (SBFL) has been proven to be an effective technique to locate faulty statement in program code. SBFL metrics exploit the records of statement execution (spectra) by pass and fail test cases for each statement to rank its likeliness to be faulty. However, in some cases, these spectra contain duplicated and ambiguous information or noise which may deteriorate the performance of SBFL metrics. We propose six noise reduction schemes to eliminate test cases which provide duplicated and ambiguous information and evaluate the resulting performance improvements in SBFL metrics. Based on our findings, we further provide a guide for SBFL practitioners to select the best performing noise reduction scheme for the SBFL metrics that they use.

Spectrum-based Fault Localization (SBFL) is a well-known debugging technique that locates fault in program code by utilizing execution profiles (spectra) of pass and fail test cases. Hence, the performance of SBFL depends on the test cases executed and the test results. In the most extreme scenarios, the debugging process may have to be conducted with only one fail test case, one pass test case or no pass test case. These scenarios might occur due to extremely high or extremely low failure rates or when software testers decide to stop running more test cases due to time and resource constraints. However, limited test case execution profiles may reduce the accuracy of SBFL metrics. In view of this, we evaluate the performance of SBFL metrics in these extreme scenarios to identify the best performing SBFL metric for each of these scenarios. From the experiment results, we have further discovered the convergence in performance for SBFL metrics under these extreme scenarios.

본 논문에서는 실시간 스펙트럼 추정기에 기반하여 시간-주파수 영역 반사파 계측 시스템에서의 동축케이블 결함을 검출하는 방법을 제안한다. 시간-주파수 영역 반사파 계측 시스템은 가우시안 포락선(Gaussian Envelop)모양의 첩 신호를 기준신호로 하여 도선에 반사파를 분석하는 기법으로써 타 방법에 비하여 높은 정확도를 자랑하는 것으로 알려져 있다. 하지만 결함 위치를 추정하기 위해 Wigner 시간 주파수 분포 함수를 이용하므로 계산량 증가에 따른 실시간 구현이 어렵다는 단점이 있었다. 이러한 단점을 극복하기 위하여 본 논문에서는 LMS 스펙트럼 추정기를 이용한 시간-주파수 영역 반사파 계측 시스템의 구현방법을 새롭게 제안한다. 제안된 기법은 실제 동축케이블에 대한 실험결과를 통하여 그 성능을 입증하도록 한다.