Search

Due to the increasing scale and complexity of software products, software maintenance especially on bug resolution has become a challenging task. Generally in large-scale software programs, developers depend on software artifacts (e.g., bug report, source code and change history) in bug repositories to complete the bug resolution task. However, a mountain of submitted bug reports every day increase the developers' workload. Therefore, 'How to effectively resolve software defects by utilizing software artifacts?' becomes a research hotspot in software maintenance. Considerable studies have been done on bug resolution by using multi-techniques, which cover data mining, machine learning and natural language processing. In this paper, we present a literature survey on tasks, challenges and future directions of bug resolution in software maintenance process. Our investigation concerns the most important phases in bug resolution, including bug understanding, bug triage and bug fixing. Moreover, we present the advantages and disadvantages of each study. Finally, based on the investigation and comparison results, we propose the future research directions of bug resolution. [ABSTRACT FROM AUTHOR]

In wireless sensor networks (WSNs), congestion may lead to a plethora of malfunctions such as packet loss, lower throughput and energy inefficiency, potentially resulting in reduced deployment lifetimes and under-performing applications. In this paper, we comprehensively investigate the drawbacks to the CTP protocol in congestion control and propose an ECA-CTP protocol that is equipped with an enhanced congestion avoidance mechanism. Distinguished from the existing protocols, the ECA-CTP protocol detects node-level and link-level congestion by queue full degree (FD) and congestion degree (CD) respectively, which are used to drive the selection of the proper parent nodes for rerouting paths as needed under an overall routing metric. We implemented the enhanced congestion avoidance mechanism for the ECA-CTP protocol based on the Forwarding Engine, Routing Engine and Link Estimator in the CTP protocol executing under the TinyOS platform. The experimental results show that ECA-CTP improves the throughput performance, and provides better performance in data yield when the sending interval is small. Moreover, ECA-CTP reduces the average energy consumption for every packet successfully received by the sink, which again validates the effectiveness of ECA-CTP. We believe that the enhanced congestion avoidance mechanism of ECA-CTP is an effective method to improve network performance when congestion is frequent. [ABSTRACT FROM AUTHOR]

The radio frequency identification (RFID) technology is greatly revolutionizing applications such as warehouse management and inventory control in retail industry. In large RFID systems, an important and practical issue is tag searching: Given a particular set of tags called wanted tags, tag searching aims to determine which of them are currently present in the system and which are not. As an RFID system usually contains a large number of tags, the intuitive solution that collects IDs of all the tags in the system and compares them with the wanted tag IDs to obtain the result is highly time inefficient. In this paper, we design a novel technique called testing slot , with which a reader can quickly figure out which wanted tags are absent from its interrogation region without tag ID transmissions. The testing slot technique thus greatly reduces transmission overhead during the searching process. Based on this technique, we propose two protocols to perform time-efficient tag searching in practical large RFID systems containing multiple readers. In our protocols, each reader first employs the testing slot technique to obtain its local searching result by iteratively eliminating wanted tags that are absent from its interrogation region. The local searching results of readers are then combined to form the final searching result. The proposed protocols outperform existing solutions in both time efficiency and searching precision. Simulation results show that, compared with the state-of-the-art solution, our best protocol reduces execution time by up to 60 percent, meanwhile promotes the searching precision by nearly an order of magnitude. [ABSTRACT FROM PUBLISHER]