基于可扩展LSH的高维动态数据索引

提出了一种可扩展的局部敏感哈希索引(SLSH),以解决高维动态数据索引中,由于数据集大小及分布特征无法确定而导致索引效率降低的问题.SLSH架构于E2LSH之上,继承了其对高维数据索引速度快,并可直接对欧式空间上的数据点进行索引的特点.为了使得哈希索引具有动态的相似性区分能力,SLSH修改了E2LSH的哈希族,通过哈希桶容量约束自适应调节哈希参数.因此对于分布密度动态变化的数据空间,SLSH也能够给出鲁棒的划分.     

基于三维体的多分辨率视频分割算法

传统视频分割算法无法处理视频中庞大的数据量,且分割结果需要保持时空连续性。针对该问题,提出一种基于三维体的多分辨率视频分割算法。在三维空间中对整个视频体进行分割,以保证时空连续性,采用多分辨率的思想,减少计算开销。实验结果表明,该算法能减少传统分割算法的时空耗费,修正连续帧的局部分割结果。     

基于保局部核RVM的说话人识别方法

针对说话人语音特征随音量、情绪、健康等因素变化呈现出的复杂分布结构,提出一种基于保局部核相关向量机(RVM)的说话人识别方法。在RVM模型所采用的高斯核函数中引入相似度因子,以保留数据局部结构,构成保局部核RVM模型。在模型训练过程中采用快速算法以避免大型矩阵逆操作,减少计算量,可适用于大样本场合。应用结果表明,该方法能加快测试速度,提高分类精度。     

BitTorrent流量控制方案

设计并实现了一个克隆Tracker以减少互联网中BitTorrent (BT)流量占用过多进出口带宽的问题。当BT客户端向Tracker发出列表请求时,Peers列表请求数据包被路由到克隆Tracker。克隆Tracker使用不同于原Tracker的列表选择算法,代替原Tracker向BT客户端返回Peers列表。克隆Tracker从原Tracker中获得并更新列表。在校园网的实地测试结果表明：在不修改BT客户端和原Tracker服务器的条件下,克隆Tracker能够有效控制所测网段BT流量占用的进出口带宽。     

基于局部多核支持向量机的视频镜头边界检测

提出了一种基于局部多核支持向量机的视频镜头边界检测方法.利用视频图像相邻帧的时空信息构建视频中间特征,在此基础上利用局部多核支持向量机将视频帧划分为边界帧和非边界帧.为了提高基于全局优化的多核支持向量机的检测精度,利用局部敏感哈希算法将视频帧投影全哈希子空间,结合多核学习方法为各个哈希子空间构建局部多核支持向量机,利用SMOTE上采样技术解决了视频图像边界帧和普通帧的不平衡问题.试验结果表明,本文提出的镜头边界检测方法的金全率和查准率得到了提高.     

基于LATE的Hadoop数据局部性改进调度算法

调度问题是目前云计算研究中的热点问题,其目的是如何协同云计算资源,使其得到充分合理的利用。数据局部性是特定云平台Hadoop的主要特性之一。针对该特性,在Hadoop原有调度算法LATE的基础上提出了一种基于数据局部性的改进算法,以解决数据局部性带来的慢任务备份执行时读取数据要占用大部分时间而影响其处理速率的问题。最后,对该算法进行了实验及性能分析,并验证了算法在提高任务的响应时间和整个系统吞吐率方面有很大改进。     

Mining students’ inquiry actions for understanding of complex systems

This study lies at an intersection between advancing educational data mining methods for detecting students’ knowledge-in-action and the broader question of how conceptual and mathematical forms of knowing interact in exploring complex chemical systems. More specifically, it investigates students’ inquiry actions in three computer-based models of complex chemical systems when their goal is to construct an equation relating physical variables of the system. The study’s participants were 368 high-school students who interacted with the Connected Chemistry (CC1¹) curriculum and completed identical pre- and post-test content knowledge questionnaires. The study explores whether and how students adapt to different mathematical behaviors of the system, examines how these explorations may relate to prior knowledge and learning in terms of conceptual and mathematical models, as well as components relating to understanding systems. Students’ data-collection choices were mined and analyzed showing: (1) In about half the cases, mainly for two out of the three models explored, students conduct mathematically-astute (fit) explorations; (2) A third of the students consistently adapt their strategies to the models’ mathematical behavior; (3) Fit explorations are associated with prior conceptual knowledge, specifically understanding of the system as complex, however, the three explorations’ fitness is predicted by the understanding of distinct sets of systems’ components; (4) Fit explorations are only somewhat associated with learning along complementary dimensions. These results are discussed with respect to 1) the importance of a conceptual understanding regarding individual system elements even when engaged in large-scale quantitative problem solving, 2) how distinct results for the different models relate to previous literature on conceptual understanding and particular affordances of the models, 3) the importance of engaging students in creating mathematical representations of scientific phenomena, as well as 4) educational applications of these results in learning environments.     

Blended learning in higher education: Students’ perceptions and their relation to outcomes

New information and communication technologies (ICTs) provide educators and learners with an innovative learning environment to stimulate and enhance the teaching and learning process. In this context, novel educational concepts such as blended learning are being developed. In the present paper, we present the results obtained from a blended learning experience carried out at the University of Granada. A total of 17 groups took part, with 1431 students registered for the 2009–2010 academic year. In this study, we use objective outcomes and the students’ perceptions regarding the blended learning activities performed. The study shows that the use of blended learning has a positive effect in reducing dropout rates and in improving exam marks. Moreover, the students’ perceptions on blended learning are interrelated, with their final marks depending on the blended learning activities, and on the students’ age, background and class attendance rate.     

Exploring the potential of the will,skill, tool model in Ghana: Predicting prospective and practicing teachers’ use of technology

Research has shown that will (positive attitudes), skill (technology competency), and tool (access to technology tools) are all essential ingredients for a teacher to effectively integrate information technology into classroom practices. This study focuses on the will, skill and tool as essential measures for the predictability of technology integration, reported by the study participants and measured by stages of adoption of teachers in Ghana. Attempts are made to explore the extent to which these parameters differ among the teachers and also influence technology integration. Furthermore, the parameters are proposed for use in modelling the process of technology integration for these teachers. Well validated instruments spanning the areas of attitudes, competencies, access and technology integration proficiencies were used to collect data from 120 mathematics prospective teachers and 60 practicing mathematics teachers from Ghana. The data was analyzed using regression analysis. The results indicated that lack of teacher anxiety was the most important dimension of attitudes, and that skill is the strongest predictor of classroom integration of technology for the teachers. Significant differences existed between practicing and prospective teachers’ computer anxieties, competencies, and access levels.     

A framework for the design and integration of collaborative classroom games

The progress registered in the use of video games as educational tools has not yet been successfully transferred to the classroom. In an attempt to close this gap, a framework was developed that assists in the design and classroom integration of educational games. The framework addresses both the educational dimension and the ludic dimension. The educational dimension employs Bloom’s revised taxonomy to define learning objectives and applies the classroom multiplayer presential game (CMPG) pedagogical model while the ludic dimension determines the gaming elements subject to constraints imposed by the educational dimension. With a view to validating the framework, a game for teaching electrostatics was designed and experimentally implemented in a classroom context. An evaluation based on pre/post testing found that the game increased the average number of correct answers by students participating in the experiment from 6.11 to 10.00, a result found to be statistically significant. Thus validated, the framework offers a promising basis for further exploration through the development of other games and fine-tuning of its components.