Abstract Collaboration relies on efficient communication among developers. Many development teams use instant messaging owing to its synchronous and real‐time nature. Despite the convenience provided by instant messaging, developers spend a great amount of time on handling information and task interruption. Consequently, productivity of developers and effectiveness of collaboration are declined. To address the issue, this work introduces an aggressive methodology of noise blocking. The methodology appropriately prioritizes messages based on collaboration requirements. A message which is not urgent for developers to collaborate with others is defined as noise, and such message is blocked to stop unnecessary interruption. To evaluate the proposed methodology, this work conducts experiments on datasets collected from real‐world projects. Then, a noise analysis tool—message analyzer for instant notification of information (MINI)—is implemented. The evaluation results show that noise hinders collaboration significantly because almost half of messages are noise. When MINI is applied, more than 80% of noise is identified, and at most 91.6% of time wasted in noise for the whole team is saved. The proposed noise blocking methodology shows promising results.

The redistribution of class responsibilities is a common reengineering practice in object-oriented (OO) software evolution. During the redistribution, developers frequently construct batched refactoring plans for moving multiple methods and fields among various classes. With an objective of carefully maintaining the cohesion and coupling degree of the class design, executing a batched refactoring plan without introducing any objective-violating side effect into the refactored code is essential. However, using most refactoring engines for batched refactoring plan execution introduces coupling-increasing Middle Man bad smell in the final refactored code and therefore makes the refactoring execution suboptimal in achieving the redistribution objective. This work proposes Obey, a methodology for optimal batched refactoring plan execution. Obey analyzes a batched refactoring plan, identifies Middle Man symptoms that cause suboptimal execution, and renovates the plan for optimal execution. We have conducted an empirical study on three open-source software projects to confirm the effectiveness of Obey in a practical context.

Code examples are important resources for expressing correct application programming interface (API) usages. However, many framework and library APIs fail in offering sufficient code examples in corresponding API documentations. This is because constructing proper code examples for documentation purpose takes significant developers' efforts. To reduce such effort, this work proposes a methodology, PropER-Doc, that recommends proper code examples for documentation purpose. PropER-Doc accepts queries from API developers and utilizes code search engines (CSEs) to collect corresponding code example candidates. The structural and conceptual links between API elements are captured from the API implementation and available API documents to guide candidate recommendation. During recommendation, PropER-Doc groups collected candidates based on involved API types for distinguishing different API usages. To assist API developers in selecting proper candidates, a diagrammatic presentation and three code example appropriateness metrics are also developed in {PropER-Doc}. Two case studies on Eclipse JDT framework are conducted to confirm the effectiveness of PropER-Doc.

Minimizing energy consumption is a fundamental requirement when deploying wireless sensor networks. Accordingly, various topology control protocols have been proposed, which aim to conserve energy by turning off unnecessary sensors while simultaneously preserving a constant level of routing fidelity. However, although these protocols can generally be integrated with any routing scheme, few of them take specific account of the issues which arise when they are integrated with geographic routing mechanisms. Of these issues, the dead-end situation is a particular concern. The dead-end phenomenon (also known as the "local maximum” problem) poses major difficulties when performing geographic forwarding in wireless sensor networks since whenever a packet encounters a dead end, additional overheads must be paid to forward the packet to the destination via an alternative route. This paper presents a distributed dead-end free topology maintenance protocol, designated as DFTM, for the construction of dead-end free networks using a minimum number of active nodes. The performance of DFTM is compared with that of the conventional topology maintenance schemes GAF and Span, in a series of numerical simulations conducted using the ns2 simulator. The evaluation results reveal that DFTM significantly reduced the number of active nodes required in the network and thus prolonged the overall network lifetime. DFTM also successfully constructed a dead-end free topology in most of the simulated scenarios. Additionally, even when the locations of the sensors were not precisely known, DFTM still ensured that no more than a very few dead-end events occurred during packet forwarding.

When people involve with software more in their daily lives, software companies must provide services through handling various operating questions that users request in the forums. However, different from conventional software companies, various types of difficulties, propositions and opinions could be issued by open source software users in addition to the operating questions. These difficulties, propositions and opinions are generally referred as questions in the forums. The questions, as valuable knowledge of the open source project, should be systematically managed. To manage the questions, a common strategy is to construct a FAQ in open source projects. The FAQ can reduce the volume of similar questions in the forums and prevent active forum members from wasting time on answering questions which are already handled before. Most previous literature focuses on existing FAQ retrieval instead of finding and constructing FAQ. This study, as a pioneering work, proposes a configurable and semi-automatic FAQ finding process to assist forum managers in constructing the FAQ. Also, two case studies are conducted to evaluate the effectiveness of the proposed FAQ finding process.

API documentation and code example are two major resources to support API usage. To find the best way to use APIs within specific programming tasks, an effective strategy to link related APIs becomes critical. Currently, many code search engines have been proposed to solve this issue. Through those search results, programmers must manually traverse across all API documents to learn the referred API calls. To ensure the productivity in the style of programming with APIs, this work provides CoDocent to help programmers review code examples found by search engines. For each found code example, CoDocent can automatically link related API documents to provide diagrams as abstractions to reflect the semantics of API calls. Two evaluations are conducted to show the effectiveness of CoDocent in investigating and adapting API calls from code examples.

Abstract Although the development of open source software (OSS) projects is known to be critically dependent on many key factors, the precise contribution of the various user and developer activities toward the development of an OSS project is unknown. Therefore, an empirical study is performed to examine the correlation between the user/developer activities and the state of development of an OSS project. It is shown that certain user/developer activities have a particular efficacy in facilitating OSS project development. The results presented in this study provide an effective approach useful in observing and evaluating the development of OSS projects. Copyright © 2009 John Wiley & Sons, Ltd.

A topology control algorithm can be applied to wireless sensor networks to construct a virtual backbone for maintaining network connectivity. For handling node failure, previous algorithms typically prefer to have redundant nodes so the power efficiency was compromised. This paper describes a Power-CDS (P-CDS) mechanism that schedules active and backup sensor nodes in the backbone for tolerating failures. When node failure is detected, both active and backup nodes will adjust their transmission ranges to maintain connectivity. Simulation results show that P-CDS forms a smaller connected dominating set than the other fault- tolerant topology control algorithm. P-CDS also provides efficient broadcast with relatively low energy consumption.

In this, the Information Age, most people are accustomed to gleaning information from the World Wide Web. To survive and prosper, a Web site has to constantly enliven its content while providing various and extensive information services to attract users. The Web Recommendation System, a personalized information filter, prompts users to visit a Web site and browse at a deeper level. In general, most of the recommendation systems use large browsing logs to identify and predict users' surfing habits. The process of pattern discovery is time-consuming, and the result is static. Such systems do not satisfy the end users' goal-oriented and dynamic demands. Accordingly, a pressing need for an adaptive recommendation system comes into play. This article proposes a novel Web recommendation system framework, based on the Moving Average Rule, which can respond to new navigation trends and dynamically adapts recommendations for users with suitable suggestions through hyperlinks. The framework provides Web site administrators with various methods to generate recommendations. It also responds to new Web trends, including Web pages that have been updated but have not yet been integrated into regular browsing patterns. Ultimately, this research enables Web sites with dynamic intelligence to effectively tailor users' needs. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 621–639, 2007.

Space requirement for storing indexes and performance for query processing are two critical issues in music information retrieval (MIR) system. To overcome difficulties in variable length of queries and enhance efficiency of music retrieval, we propose an effective and efficient numeric indexing structure. It differs greatly from preexisting researches in textual indexing techniques. We show how the development of this framework has been motivated and demonstrate how the technique may be naturally applied to solve this two fundamental MIR issues. Experiments are performed to compare our method with previous solutions. The results show that our method is more scalable and economical than previous methods. The method we proposed can achieve dramatically and significantly improvement in saving time and storing space for retrieving and indexing

In order to improve lifetime of sensors, it is important to obtain a smaller partial set of working sensor nodes for full coverage in wireless sensor networks. This paper presents a decentralized self-configured method for determining active nodes required to ensure complete coverage. A two-way coverage mechanism identifies blind/overlapping areas and activates/deactivates sensor nodes as required to maintain the coverage. The mechanism was implemented successfully using the network simulator NS-2. The performance was compared to that provided by three other alternative approaches, including OTTAWA, PEAS, and OGDC. The results show that the two-way algorithm is network scalable and coverage efficient

Ad hoc networks have been extensively deployed in recent years. In such networks, obtaining a high efficiency is difficult to achieve due to mobility. Many routing approaches have been proposed to improve the performance of ad hoc networks, including table-driven and demand-driven routing protocols. Geographic routing provides a suitable solution for large-scale and dynamic networks, and reduces link failure problems during packet routing. In wireless networks, nodes movement may cause a network partition, which hinders both data transmission and information availability within the network. Several schemes have been proposed for resolving the partition problem in wireless ad hoc networks. In general, the previous solutions either relied on the use of mobile devices with known trajectories or introduced additional specific mobile nodes. By contrast, this paper proposes a scheme for overcoming the problem of network partitions using only the available devices in the environment. With the scheme, the source node searches for another mobile node, designated as the helping node, which is able to meet the destination. The selected mobile node then carries the packet toward the destination. If the helping node changes its trajectory before it forwards the packet to the destination node, a hand-off scheme is activated and the data packet is transferred to another mobile node for onward transmission

With the progress of advanced technology, people anticipate better quality in the medical health care service. Due to more robust requirements in medical environments, higher availability and reliability are expected. This paper describes a recovery scheme for disconnection failures in a Web-based medical teleconsultation system. With the support, the disconnected clients can re-enter the system to resume the unfinished discussion using the synchronization mechanisms. The experiments have shown that the mechanism performed successfully. The lazy synchronization further reduced the required time that the clients had to wait for joining the consultation after network disconnections

This article comments on "automatic analysis of consistency between requirements and designs".

Location service support is required for mobile nodes using geographic ad hoc routing. The mobile nodes need location information of destinations for sending data packets. Due to mobility or node failures, queries to the location servers may not always succeed. This paper presents a distributed location service (DLS) that employs dual servers to maintain position information of mobile nodes and to achieve efficient performance. With the scheme, the number of failed queries, including no response and erroneous results, can be reduced. DLS has been implemented and evaluated using the ns2 simulator. The experimental results show that DLS not only improved service availability but also location query latency.

We develop an algorithm for chord decision for monophonic music, and it can be applied to music indexing and automatic composition systems. The basic ideas of the proposed algorithm can be divided into two phases: the local recognition phase and the global decision phase. The algorithm analyzes the music and assigns a set of chord candidates in the local recognition phase, while deciding the best appropriate chord according to the chord progression rules in the global decision phase. In order to improve the perceptual accuracy, we consider the beat of corresponding notes in a measure and eliminate the effect of the passing notes and ornaments.

A mobile ad hoc network consisting of a set of mobile nodes does not have any infrastructure support or central management. Data packets are routed by the mobile nodes in the network instead of base stations. Due to node mobility or geographical limitations, the ad hoc network topology may be partitioned. Data communication and information availability are thus affected. The disconnection problem makes a critical strike on ad hoc routing protocols because most protocols typically assume that the ad hoc network is always connected. We describe an approach to recovering the disconnected mobile ad hoc networks by deploying forwarding nodes. The forwarding nodes can automatically move to appropriate locations for interconnecting network partitions. The mechanism is distributed and self-organized and can be integrated with other routing protocols. The mechanism has been implemented in the network simulator ns-2. The simulation results show that the algorithm can efficiently improve information availability and recover network partitions.

When studying [T.C. Oliveira et al. (2004)], we found an error and some ambiguous parts. In this paper, we state those errors.

OO software engineering (OOSE) has been a popular methodology for years; however, there are still some issues remaining unsolved: a generic mechanism for checking consistency of designs is still lacking; software has some problems resulting from process issue; and imperative engineer have a huge gap to adopt OOSE. These three issues intersect in the early analysis phase, therefore we represent a new methodology that provides a complete global view of OO software system that solves issues we identified, and uses requirements document and some analysis documents as foundation. Rules and a case study are also presented to exemplify the result of applying our methodology on both OOSE and imperative software engineering.

Many software systems are established using client-server models. If a program on the server needs to be updated due to software maintenance, the service provided by the program will be required to terminate. The clients cannot be served until the update process is completed. The update process obviously reduces commercial profit especially for e-commerce systems. Therefore, a nonstop software update scheme is needed for high system availability. This paper develops an NSU system to update general server programs without stopping services. The NSU system can take over the task of old version using a redundant server for updating. The system supports applications with shared variables and maintains data consistency during software update. The current implementation is designed for Java programs running on the Linux operating system. Experimental results show that the NSU system incurred less than 1% overhead during normal execution.

To extract music features from the raw data of music object and organize them as the music indices is important for music retrieval. A repeating pattern is a series of notes which appear more than once. Most of the repeating patterns are themes or tones for people to remember easily. A figure is defined as a melody contour of a musical segment. A sequence pattern is a melody segment that has the same figure with other melody segments. In this paper, we use the idea of interval between two adjacent notes to form quantized melody contour for representing music objects. This representation differs from existing methods that use notes to form a melody string. We also propose a method to find significant repeating figures. These figures could cover most of the repeating patterns that are in a noted melody string. In addition, the number of repeating figures found in samples of music is less than that of repeating patterns. As a result, the total execution time and memory space can be dramatically decreased.

Heterogeneous computing environments, where computers may have different instruction set architectures, data representations, and operating systems, complicate checkpointing and recovery of processes. This paper describes an approach to recovery and an implementation, PREACHES, that provides portable checkpointing of single-process applications in heterogeneous systems using checkpoint propagation. The checkpoint propagation mechanism creates machine-dependent checkpoints for different architectures in the heterogeneous environment. A process is restored on a specific machine with the checkpoint that is appropriate for the architecture. An implementation of PREACHES has been evaluated on a heterogeneous network of workstations, including Sun, HP, and Pentium machines. The experimental results show that PREACHES achieves efficient checkpointing and rapid recovery.

After reviewing the regular paper "On Object Systems and Behavioral Inheritance" in IEEE Transactions on Software Engineering, vol. 28, no. 9, Sept. 2002, and discussing it with Professor H.C. Jiau, several errors were found and are stated.

We introduce an innovative approach to wrapping semi-structured web pages in order to generate structured data. Unlike other work in this area that is based on physically specifying the location of information, our approach is based on human design psychology that captures more stable features in web pages, which we believe renders a more robust result in coping with changes in the web pages. In this paper, we focus on the product advertisement domain, and a set of design psychology principles for product advertisement is presented and used to design the wrapping rules. A case study in the mobile phone advertisement domain is used to evaluate this approach.

We propose a distributed software integration architectural style (DSIAS) to provide a blueprint and reference document that would be useful to software system designers when integrating commercial off-the-shelf (COTS) products under distributed and Internet environment. DSIAS provides a framework indicating the structure topology to put lots of originally unrelated COTS products together into a COTS based system. We then successfully applied DSIAS to the design of an example, a distributed graphical parking lot management system.

Software updating is an inevitable process in the lifetime of a computer system. Numerous update mechanisms have been applied to software products. However, only little attention has been devoted to online nonstop software updating. Traditional update utilities typically require programs to stop execution during modifications, and this decreases the availability of the systems. For e-commerce (electronic commerce) companies, improving system availability implies increasing opportunities for greater business profit. Therefore, minimizing the system maintenance time for necessary software updates becomes a critical issue. This paper describes an approach to nonstop software updating. The approach composes a program using two replicated execution blocks. By switching between the execution blocks, the program can be modified without terminating its service. The paper also discusses the system environments that are required in order to support the approach.

The growing importance of VLSI is gaining it much attention, but the increasing complexity of VLSI also creates lots of problems for computer scientists to work on. If no other new way to help designers is developed, then the whole design process will become more difficult to maintain. That's why there is a need for an object-oriented (OO) design framework for the CAD world. Not only is it necessary to develop new methods for CAD, but the extension of reuse technology into the design process will also become a main key to success. We propose an OO-based framework with an object specification language (OSL) for reuse. In our OO design framework, CAD tools are reverse-engineered into a toolbox in a reuse library. During the design (reuse) process, toolboxes are selected automatically for the design process. Thus, tool selection, integration and adoption problems are merged into the design process, together with the OSL specification. With this OO design framework, tool reuse and design data reuse can be automatically integrated into the design process.