复合分支预测中选择算法的研究

随着高性能微处理器的流水线越来越深, 分支预测的精度不够高已经成为制约微处理器性能进一步提高的瓶颈。由于一种分支预测方式总会有一些缺陷, 所以复合分支预测方式就被提出来。也就是利用几种分支预测方式同时进行预测, 再基于某种选择算法选择采用哪一种预测方式的结果。基于这种复合分支预测方式, 提出几种了新的选择算法实现。     

一种基于合作博弈的均衡路由方法

网络资源公平性分配是网络可存性研究中的关键问题,路由选择算法是影响网络资源分配的公平性和均衡性的关键因素。本文研究路由器路径选择中的均衡性问题,提出了基于博弈论思想的解决方案,即将IPv6协议中的任意播路由问题看作是合作参与者间的博弈;针对该博弈问题,建立了路由算法的合作博弈模型,求得了该博弈均衡点,并在此基础上,提出了一种基于合作博弈的均衡路由方法;最后通过实验仿真了算法结果。     

Dropout prediction in e-learning courses through the combination of machine learning techniques

In this paper, a dropout prediction method for e-learning courses, based on three popular machine learning techniques and detailed student data, is proposed. The machine learning techniques used are feed-forward neural networks, support vector machines and probabilistic ensemble simplified fuzzy ARTMAP. Since a single technique may fail to accurately classify some e-learning students, whereas another may succeed, three decision schemes, which combine in different ways the results of the three machine learning techniques, were also tested. The method was examined in terms of overall accuracy, sensitivity and precision and its results were found to be significantly better than those reported in relevant literature.     

Real-time collaboration of virtual laboratories through the Internet

Web-based learning environments are becoming increasingly popular in higher education. One of the most important web-learning resources is the virtual laboratory (VL), which gives students an easy way for training and learning through the Internet. Moreover, on-line collaborative communication represents a practical method to transmit the knowledge and experience from the teacher to students overcoming physical distance and isolation. Considering these facts, the authors of this document have developed a new dynamic collaborative e-learning system which combines the main advantages of virtual laboratories and collaborative learning practices. In this system, the virtual laboratories are based on Java applets which have embedded simulations developed in Easy Java Simulations (EJS), an open-source tool for teachers who do not need complex programming skills. The collaborative e-learning is based on a real-time synchronized communication among these Java applets. Therefore, this original approach provides a new tool which integrates virtual laboratories inside a synchronous collaborative e-learning framework. This paper describes the main features of this system and its successful application in a distance education environment among different universities from Spain.     

Probabilistic proximity search: Fighting the curse of dimensionality in metric spaces

Proximity searches become very difficult on “high dimensional” metric spaces, that is, those whose histogram of distances has a large mean and/or a small variance. This so-called “curse of dimensionality”, well known in vector spaces, is also observed in metric spaces. The search complexity grows sharply with the dimension and with the search radius. We present a general probabilistic framework applicable to any search algorithm and whose net effect is to reduce the search radius. The higher the dimension, the more effective the technique. We illustrate empirically its practical performance on a particular class of algorithms, where large improvements in the search time are obtained at the cost of a very small error probability.     

教育客户服务中心结构设计

教育客户服务中心系统是以提高教育服务质量和效率为目标，研究相关的信息描述、定义、存储、检索、交换、分析和挖掘技术，综合构成教育客户服务中心的前台接入和后台处理的最新技术，通过与教学服务管理系统和教学行为分析和质量评估系统集成，为高校的招生、教务管理等教育服务管理工作提供高效的辅助手段，促进教育资源的信息规范化。     

Delivery of medical multimedia contents through the TCP/IP network using RealSystem

We developed a low cost, user-friendly multimedia delivery system, to provide medical lectures saved as multimedia contents to persons engaged in medicine. This system was created using the RealSystem package with the TCP/IP network. Users can review lectures and medical meeting presentations with video and audio through the Internet, whenever convenient. Each medical source of video and slide has been clearly displayed on a screen. Members of medical associations or medical students can easily review the most interesting parts of these files. This system is being used efficiently in distance learning and aids the diffusion of the latest information and technology to busy physicians and medical students.     

Comparing hybrid learning with traditional approaches on learning the Microsoft Office Power Point 2003 program in tertiary education

The purpose of this study was to determine the effectiveness of a hybrid learning approach to deliver a computer science course concerning the Microsoft office PowerPoint 2003 program in comparison to delivering the same course content in the form of traditional lectures. A hundred and seventy-two first year university students were randomly assigned into two teaching method groups: traditional lecture instruction (TLI) and hybrid lecture instruction (HLI). Each group received six 95-min periods of instruction divided into 4 sections: a) 5-min brief outline of the key learning points, b) 40-min lecture on general knowledge c) 45-min constructivist-inspired learning activities and d) 5-min summary on key learning points. In the beginning and the end of this study students completed a 17-item multiple choice knowledge test. Two-way analysis of variances (ANOVA), with repeated measures on the last factor, were conducted to determine effect of method groups (TLI, HLI) and measures (pre-test, post-test) on knowledge test. The measures main effect was significant, as well as the groups x measures interaction effect. Two independent-samples t test were conducted to follow up the significant interaction. Differences in mean ratings of knowledge performance between the two teaching groups were not significantly different at first measure, while the TLI method group yielded a significantly lower mean rating at second measure. The findings indicated that HLI approach might be a superior option for undergraduate students on learning the Microsoft office PowerPoint 2003 program.     

The effect of motivational scaffolding on procrastinators’ distance learning outcomes

The purpose of the research was to determine experimentally whether the addition of features to enhance learner motivation and collaboration, termed motivational scaffolding, to the “traditional” distance learning design improved engagement, and performance, particularly among procrastinators. Two versions of a web-based five-credit study skills course, both covering the same content and sharing all features save for the scaffolding, were compared: traditional-distance, and motivationally-scaffolded distance, during each of two terms. Motivational scaffolding consisted of using chat to run study skills support groups, where students were helped to stay on task, and instructor office hours. Students were classified as either high or low procrastinators, and randomly assigned to each version, and two instructors alternated between versions taught from one term to the other. Results showed that procrastinating students, for whom the lack of structure of distance learning may be problematic, performed better in the motivationally-scaffolded version than the traditional, while non-procrastinating students performed equally in both.     

Extending metric multidimensional scaling with Bregman divergences

Sum of weighted square distance errors has been a popular way of defining stress function for metric multidimensional scaling (MMDS) like the Sammon mapping. In this paper we generalise this popular MMDS with Bregman divergences, as an example we show that the Sammon mapping can be thought of as a truncated Bregman MMDS (BMMDS) and we show that the full BMMDS improves upon the Sammon mapping on some standard data sets and investigate the reasons underlying this improvement. We then extend a well known family of MMDS, that deploy a strategy of focusing on small distances, with BMMDS and investigate limitations of the strategy empirically. Then an opposite strategy is introduced to create another family of BMMDS that gives increasing mapping quality. A data preprocessing method and a distance matrix preprocessing are introduced.