Students’ perceptions of teaching technologies, application of technologies, and academic performance

This study examined business students’ perceptions of four objectives (i.e., Enjoyment, Learning, Motivation, and Career Application) across five teaching technologies (i.e., Projector, PowerPoint, Video, the Internet, and Lecture), business professors’ effective application of technologies, and students’ academic performance. We collected data from 215 students at a regional state university in the USA. We developed Students’ Perceptions of Technology Scale, SPOTS, specifically for the present study, used the most rigorous criteria, and investigated reliability, convergent and discriminant validity, exploratory and confirmatory factor analysis, and measurement invariance of this scale. Mean scores revealed that Video conveyed the highest amount of Enjoyment. PowerPoint provided the highest amount of Learning and Motivation. The Internet provided the highest Career Application for future jobs. Younger students preferred Video, whereas older students favored Lecture. Regression results showed that the use of Video for Learning, Projector and Lecture for Enjoyment, PowerPoint for career and Motivation, and the Internet for Learning contributed to professors’ teaching effectiveness. Students’ high ratings for professors’ effective use of the Lecture method and low expectation for the use of a Projector predicted their self-reported GPA (academic performance). Professors may use a different mix of technologies in the classroom and use them creatively in order to promote the most Learning for students and satisfy students’ Learning needs and objectives.     

Learning teamwork skills in university programming courses

University courses about computer programming usually seek to provide students not only with technical knowledge, but also with the skills required to work in real-life software projects. Nowadays, the development of software applications requires the coordinated efforts of the members of one or more teams. Therefore, it is important for software professionals to master the sort of skills that assure the success of teamwork, such as communication, leadership, negotiation, or team management. However, these abilities are difficult to teach, one of the reasons being that they require true commitment from the students. However, today students are taking a more and more passive role in their own education, two of the more evident consequences being the increase in dropout rates and the decrease in marks obtained in exams. The NUCLEO e-learning framework has been designed to promote the effective acquisition of teamwork skills and, at the same time, to promote the more active participation of the students in their own learning process. NUCLEO adopts a socio-constructivist pedagogical approach that pursues the development of communities of practice for Problem Based Learning. Our research has rooted the design decisions of NUCLEO in the analysis of its socio-cultural environment with Activity Theory, which considers conflicts within groups as the impetus of their evolution and the forges of their environments. This paper presents the analysis of the main features of NUCLEO according to Activity Theory, as well as the experimental results obtained with the framework in three different case studies in university courses.     

Symmetric active/active metadata service for high availability parallel file systems

High availability data storage systems are critical for many applications as research and business become more data driven. Since metadata management is essential to system availability, multiple metadata services are used to improve the availability of distributed storage systems. Past research has focused on the active/standby model, where each active service has at least one redundant idle backup. However, interruption of service and even some loss of service state may occur during a fail-over depending on the replication technique used. In addition, the replication overhead for multiple metadata services can be very high. The research in this paper targets the symmetric active/active replication model, which uses multiple redundant service nodes running in virtual synchrony. In this model, service node failures do not cause a fail-over to a backup and there is no disruption of service or loss of service state. A fast delivery protocol is further discussed to reduce the latency of the total order broadcast needed. The prototype implementation shows that metadata service high availability can be achieved with an acceptable performance trade-off using the symmetric active/active metadata service solution.     

Performance analysis and partner selection for cooperative diversity based on MQAM modulation

An adaptive decode-and-forward (DF) cooperative diversity system based on quadrature modulation is proposed, in which each user is allowed to transmit its own and the partner’s data simultaneously via the in-phase and quadrature components of M -ary quadrature amplitude modulation (MQAM) constellation. Cooperative transmission in this way can avoid the bandwidth expansion in traditional cooperative systems. The closed form expression of the average bit error rate (BER) performance is derived in terms of the...     

Using frameworks to develop a distributed conferencing system: an experience report

Application frameworks are a powerful means to reduce software development costs while improving quality. However, at the same time they are difficult to select and understand, as well as hard to learn, use, and debug effectively and efficiently. In this paper we report the story of eConference, a distributed conferencing system that was developed as part of a broader research effort. Here we discuss the lessons learned from the evolution of our conferencing tool over four generations, which have been necessary to find good frameworks and build a flexible distributed tool. Copyright © 2009 John Wiley & Sons, Ltd.     

The provision of online public goods: Examining social structure in an electronic network of practice

Electronic networks of practice are computer-mediated social spaces where individuals working on similar problems self-organize to help each other and share knowledge, advice, and perspectives about their occupational practice or common interests. These interactions occur through message postings to produce an on-line public good of knowledge, where all participants in the network can then access this knowledge, regardless of their active participation in the network. Using theories and concepts of collective action and public goods, five hypotheses are developed regarding the structural and social characteristics that support the online provision and maintenance of knowledge in an electronic network of practice. Using social network analysis, we examine the structure of message contributions that produce and sustain the public good. We then combine the results from network analysis with survey results to examine the underlying pattern of exchange, the role of the critical mass, the quality of the ties sustaining participation, the heterogeneity of resources and interests of participants, and changes in membership that impact the structural characteristics of the network. Our results suggest that the electronic network of practice chosen for this study is sustained through generalized exchange, is supported by a critical mass of active members, and that members develop strong ties with the community as a whole rather than develop interpersonal relationships. Knowledge contribution is significantly related to an individual's tenure in the occupation, expertise, availability of local resources and a desire to enhance one's reputation, and those in the critical mass are primarily responsible for creating and sustaining the public good of knowledge. Finally, we find that this structure of generalized exchange is stable over time although there is a high proportion of member churn in the network.     

基于代理的工作流邦联及子流调用框架

在分析层次工作流建模和工作流执行时互操作研究的基础上,设计了一个基于代理的邦联及子流调用框架,将层次化建模技术、流程互操作技术和异构数据模型映射和转换技术集成在一起,同时提供了异常处理和灾难恢复功能,真正从业务层次上解决了流程协作问题,并在TiPLM2.9上实现了该解决方案.流程实例之间通过代理进行交互,各个流程独立运行在自己的工作流引擎中,实现了松耦合和隔离性,增强了系统健壮性.     

一种实时可靠的移动无线传感器网络贪婪地理路由协议

随着定位装置和定位算法的成熟,基于地理位置信息的贪婪地理路由协议受到广泛的关注与研究.但是,在移动无线传感器网络贪婪地理路由协议中,周期性信标交换条件下采用贪婪转发策略会引起通信暂盲现象,造成数据的丢失.基于右手法则的面遍历算法,对路由空洞的形状不能进行感知,数据转发具有很大的盲目性,转发路径有时比最优路径长很多,造成数据传输时延的增加.针对上述问题提出一种实时可靠的QoS贪婪地理路由协议,该协议通过自适应信标交换算法、基于过渡带思想的贪婪转发策略和基于路标迭代提取和剔除的自适应空洞处理算法,使得数据分组能够实时可靠地传输.NS-2仿真结果表明该协议在不增加控制开销的情况下,能够有效减缓通信暂盲现象,高效地处理路由空洞问题,大大提高协议的实时性和可靠性,可应用于对实时性和可靠性有一定要求的大规模移动无线传感网络.     

基于IPv6的接收者匿名Crowds系统

基于下一跳重路由方式的Crowds匿名通信系统存在较多缺点。提出基于IPv6协议的Crowds系统,解决发送者与最后一跳的秘密共享问题。理论分析和实验结果表明,该系统的抗攻击能力与源路由方式相等,实现了接收者匿名,减少了通信延迟。 分类号 TP393