Recent years have experienced sustained focus in research on software defect prediction that aims to predict the likelihood of software defects. Moreover, with the increased interest in continuous deployment, a variant of software defect prediction called Just-in-Time Software Defect Prediction (JIT-SDP) focuses on predicting whether each incremental software change is defective. JIT-SDP is unique in that it consists of two interconnected data streams, one consisting of the arrivals of software changes stemming from design and implementation, and the other the (defective or clean) labels of software changes resulting from quality assurance processes. We present a systematic survey of 67 JIT-SDP studies with the objective to help researchers advance the state of the art in JIT-SDP and to help practitioners become familiar with recent progress. We summarize best practices in each phase of the JIT-SDP workflow, carry out a meta-analysis of prior studies, and suggest future research directions. Our meta-analysis of JIT-SDP studies indicates, among other findings, that the predictive performance correlates with change defect ratio, suggesting that JIT-SDP is most performant in projects that experience relatively high defect ratios. Future research directions for JIT-SDP include situating each technique into its application domain, reliability-aware JIT-SDP, and user-centered JIT-SDP.

In wireless sensor networks, some sensor nodes are put in sleep mode while other sensor nodes are in active mode for sensing and communication tasks in order to reduce energy consumption and extend network lifetime. This approach is a special case (k=2) of a randomized scheduling algorithm, in which k subsets of sensors work alternatively. In this paper, we first study the randomized scheduling algorithm via both analysis and simulations in terms of network coverage intensity, detection delay, and detection probability. We further study asymptotic coverage and other properties. Finally, we analyze a problem of maximizing network lifetime under quality of service constraints such as bounded detection delay, detection probability, and network coverage intensity. We prove that the optimal solution exists, and provide conditions of the existence of the optimal solutions.

Usage of payment cards such as credit cards, debit cards, and prepaid cards, continues to grow. Security breaches related to payment cards have led to billion dollar losses annually. In order to offset this trend, major payment card networks have founded the Payment Card Industry (PCI) Security Standards Council (SSC), which has designed and released the PCI Data Security Standard (DSS). This standard guides service providers and merchants to implement stronger security infrastructures that reduce the risks of security breaches. This article mainly discusses the need for the PCI DSS and the data security requirements defined in the standard to address the ongoing security issues, especially those pertaining to payment card data handling. It also surveys various technical solutions, offered by a few security vendors, for merchant companies and organizations involved in payment card transaction processing to comply with the standard. The compliance of merchants or service providers to the PCI DSS are assessed by PCI Qualified Security Assessors (QSAs). This article thus discusses the requirements to become PCI QSAs. In addition, it introduces the PCI security scanning procedures that guide the scanning of security policies of a merchant or service provider and prepare relevant reports. We believe that this survey sheds light on potential technical research problems pertinent to the PCI DSS and its compliance.

In the last two decades we have witnessed the tremendous success of the Internet and its technologies. Wireless Internet access becomes important to continue this success. However, wireless Internet access suffers from limited battery power, limited bandwidth, high mobility, and an increasing degree of heterogeneity. Cache mechanisms have been proposed to improve access latency, reduce battery power consumption, and reduce bandwidth usage in the wireless Internet. In this article we discuss issues in wireless Internet caching. In particular, we classify and survey cache access mechanisms and replacement algorithms, which should be designed considering both the limitations of wireless networks/devices and heterogeneity of the future wireless Internet