Yu-Seung Ma

Mutation testing cost reduction by clustering overlapped mutants

We defined the term conditionally-overlapped (c-overlapped) mutants.C-overlapped mutants are expected to produce the same results against a test case.Clustering c-overlapped mutants effectively reduces the cost of mutation testing.Clustering c-overlapped mutants retains the effectiveness of mutation testing. Mutation testing is a powerful but computationally expensive testing technique. Several approaches have been developed to reduce the cost of mutation testing by decreasing the number of mutants to be executed; however, most of these approaches are not as effective as mutation testing which uses a full set of mutants. This paper presents a new approach for executing fewer mutants while retaining nearly the same degree of effectiveness as is produced by mutation testing using a full set of mutants. Our approach dynamically clusters expression-level weakly killed mutants that are expected to produce the same result under a test case; only one mutant from each cluster is fully executed under the test case. We implemented this approach and demonstrated that our approach efficiently reduced the cost of mutation testing without loss of effectiveness.

Characterizing non-deadlock concurrency bug fixes in open-source Java programs

Fixing a non-deadlock concurrency bug is a difficult job that sometimes introduces additional bugs and requires a long time. To overcome this difficulty and efficiently perform fixing jobs, engineers should have broad knowledge of various fix patterns, and the ability to select the most proper one among those patterns based on quantitative data gathered from real-world bug databases. In this paper, we provide a real-world characteristic study on the fixes of non-deadlock concurrency bugs to help engineers responsible for program maintenance. In particular, we examine various fix patterns and the factors that influence the selection of those patterns with respect to the preexistence of locks and failure types. Our results will provide useful information for engineers who write bug patches, and researchers who study efficient testing and fixing techniques.

Combining weak and strong mutation for a noninterpretive Java mutation system

Because of the computationally expensive cost of mutation testing, automated system support is indispensable for conducting mutation testing. Mutation systems can be classified into interpretive and noninterpretive, but recent systems are noninterpretive. Weak mutation is a well‐known cost reduction method of mutation testing, but it is not directly applicable to noninterpretive mutation systems. To address the problem and take advantage of the efficiency of weak mutation, this paper presents a combined weak and strong mutation for noninterpretive Java mutation systems. The new term ‘serialmutant’ is defined as a specialized program to conduct weak mutation against all mutants in an execution and report only weakly killed mutants as strong mutation candidates. Then strong mutation is conducted only for those reported mutants. The paper also describes an implementation based on a previous Java mutation tool, MuJava. Method‐level mutation operators for Java are also redesigned. Experimental results show that the proposed approach efficiently improves the mutation cost in a noninterpretive mutation system. Copyright

RealSSim: a simulator for indoor sensor network systems

Existing sensor network simulators are not appropriate for indoor sensor network systems. We present RealSSim, the sensor network simulator especially developed for indoor sensor networks. RealSSim considers the structure of buildings and the quality of construction materials for accurate radio propagation analysis. It also supports an attractive visualization of the level as commercial products. In our demonstration, we show the whole process of simulation for two indoor sensor network systems.

Performance comparison of MRTOS and VxWorks in MultiBench benchmark suite

Recently, multiple core systems are widely used in various area. To meet the needs of mission-critical applications running on multicore systems, a realtime operating system (RTOS) and verification testing for multicore are absolutely necessary. We have developed the multicore RTOS (MRTOS) for supporting the symmetric multiprocessing. It includes multicore system BSP, multicore kernel, middleware, and IDE. To evaluate the developed RTOS, in this paper, we have compared the performance of the VxWorks and the developed RTOS by using the embedded MultiBench algorithms. We observed that the developed RTOS is able to achieve more than 90% of the performance of VxWorks on average.

Test system for device drivers of embedded systems

Device drivers are difficult to write and error-prone and thus constitutes the main portion of system failures. Therefore, to ensure that device drivers can run properly, their qualities have to be assured. In this paper, we suggested an architecture of a test system for device drivers. This architecture is designed to reflect embedded systems whose resources are usually limited. We also propose a reusable test case generation method for device drivers. We hope our method reduces the high cost of testing device drivers