融合“用户-项目-用户兴趣标签图”的协同好友推荐算法

随着社交网络的用户数量呈爆炸式增长,如何为用户推荐具有相同兴趣爱好的好友已成为当前研究的焦点。为此,提出了一种基于"用户-项目-用户兴趣标签图"的协同好友推荐算法。该算法首先利用基于"用户-项目-标签"的三部图物质扩散推荐算法来计算用户之间的相似度,并引入"用户-用户兴趣标签图"二元关系,通过用户的兴趣标签图来发掘用户的兴趣主题;然后根据用户主题分布,利用KL距离来计算用户之间的相似度;最后将两组结果采用调和平均数方式融合得到用户间的综合相似度,并进行好友的推荐。通过在Delicious和Last.fm数据集上的实验证明,该算法能有效提高Top-N推荐的准确率和召回率,同时通过在学术社交网站——学者网数据集上进行的学者推荐实验表明,该算法能有效提高核心用户的推荐度。     

基于社会化标签和历史价格曲线的网络结构个性化推荐方法

社会化标签包含商品丰富的内容,体现用户对商品的个性偏好,而商品的历史价格曲线影响用户的购买倾向。为此,提出社会化标签和历史价格曲线的个性化推荐方法。将用户-标签-商品的三部图网络结构分解为用户-标签、标签-商品的二部图网络结构。在用户-标签二部图中,利用商品历史价格曲线的权重,基于商品历史价格曲线求得用户对标签的评分,并区分用户对标签的积极和消极兴趣。在标签-商品的二部图中,计算标签对商品的重要程度。综合2种方法进行商品推荐,实验结果验证了提出方法能够有效提高推荐的召回率和多样性。     

融合偏好度与网络结构的推荐算法

针对传统推荐系统追求推荐列表的准确率而忽略推荐的多样性以及数据集信息缺失等问题，提出了融合偏好度与网络结构的推荐算法。通过用户历史反馈数据分析用户偏好度，将偏好度与二部图随机游走推荐算法融合，初步得出项目推荐列表；利用用户-标签二部图，挖掘用户不跟随大众的喜好标签，得到推荐项目列表；根据模型融合得到最终的推荐结果。实验表明，新算法在保持较好精确率和召回率的情况下，有效提高了推荐的多样性。     

基于协同矩阵分解的社会化标签系统的资源推荐

应用来自Delicious的数据集, 通过对精确度和召回率等指标的测评, 研究了协同矩阵分解对社会化标签系统中资源推荐的有效性问题, 由于用户、资源、标签之间具有一定的相似性, 采用了通过同时分解三者在不同方向的潜在兴趣值, 对用户推荐其潜在兴趣方向相近的资源的方法。与协同过滤、图结构分析的结果进行了对比, 研究结果表明该方法要优于其他方法。为了证明协同矩阵分解的有效性, 对正规化、学习率、UT因子和IT 因子等各个变量也进行了参数敏感度分析。     

基于标签权重的协同过滤推荐算法

针对传统协同过滤推荐算法中由于相似度计算导致推荐精度不足的问题,提出一种基于标签权重相似度量方法的协同过滤推荐算法。首先,通过改进当前算法中标签权重的计算,并构成用户-标签权重矩阵和物品-标签权重矩阵;其次,考虑到推荐系统是以用户为中心进行推荐,继而通过构建用户-物品关联矩阵来获取用户对物品最准确的评价和需求;最后,根据用户-物品的二部图,利用物质扩散算法计算基于标签权重的用户间相似度,并为目标用户生成推荐列表。实验结果表明,与一种基于"用户-项目-用户兴趣标签图"的协同好友推荐算法（UITGCF）相比,在稀疏度环境为0.1时该算法的召回率、准确率和F1值分别提高了14.69%、9.44%、17.23%。当推荐项目数量为10时,三个指标分别提高了17.99%、8.98%、16.27%。结果表明基于标签权重的协同过滤推荐算法可有效提高推荐结果。     

基于标签主题的协同过滤推荐算法研究

传统基于标签的推荐算法仅考虑用户的评分信息,导致推荐准确度不高。为解决该问题,提出一种改进的协同过滤推荐算法。对用户-标签矩阵、资源-标签矩阵进行潜在Dirichlet分布建模,发掘推荐系统中的潜在语义主题,从语义层面计算用户对各资源的偏好概率,将计算出的偏好概率与协同过滤算法计算出的资源相似度相结合,预测用户偏好值,实现个性化推荐。在Movielens数据集上的实验结果表明,与传统基于标签的推荐算法相比,该算法能消除标签中存在的同义词、多义词等语义模糊问题,同时提高推荐准确度。     

融合朋友关系和标签信息的张量分解推荐算法

针对大众标注网站项目推荐系统中存在数据矩阵稀疏性影响推荐效果的问题,考虑矩阵奇异值分解(SVD)能有效地平滑数据矩阵中的数据,以及朋友圈能够反映出一个人的兴趣爱好,提出了一种融合朋友关系和标签信息的张量分解推荐算法。首先,利用高阶奇异值分解(HOSVD)方法对用户-项目-标签三元组信息进行潜在语义分析和多路降维,分析用户、项目、标签三者间关系;然后,再结合用户朋友关系、朋友间相似度,修正张量分解结果,建立三阶张量模型,从而实现推荐。该模型方法在两个真实数据集上进行了实验,结果表明,所提算法与高阶奇异值分解的方法比较,在推荐的召回率和精确度指标上分别提高了2.5%和4%,因此,所提算法进一步验证了结合朋友关系能够提高推荐的准确率,并扩展了张量分解模型,实现用户个性化推荐。     

基于综合相似度和社交标签的推荐算法

针对传统个性化推荐方法所面临的冷启动、数据稀疏等问题,本论文结合了项目组的前期研究,在综合考虑用户特征和用户信任度的基础上,引入了用户兴趣,形成综合相似度.针对目前推荐系统中评分数据较少的问题,论文结合了社交标签,丰富了推荐数据.首先利用综合相似度,找到用户的相似近邻,并将相似近邻所标注的标签形成一个标签集.其次利用基于标签的推荐算法,产生最终的推荐列表.实验结果表明,该算法能够有效提高推荐的准确率和召回率.     

基于用户标注行为的潜在好友推荐

目前多数社交网络主要根据已有好友关系推荐潜在好友,用户的兴趣爱好不作为主要考虑因素;此外,如何从大量数据中精确地提取用户的兴趣爱好是一项十分艰巨的任务。为此,提出一种在大量标注行为数据中精确挖掘出用户的兴趣爱好,并据此推荐具有相同兴趣爱好的潜在好友的算法--基于标注的好友推荐(FRBT)算法。首先使用词频-逆向文件频率(TF-IDF)对标签进行聚类,将语义相似的标签聚成话题;然后在话题的基础上提出一种新的相似度公式来计算用户相似度;再融合基于话题与基于物品的用户相似度,将相似度较高的用户作为潜在好友进行推荐。在Delicious数据集上以准确率和召回率为指标与item、tag和tri-graph三种算法进行比较,实验验证了该算法能够更准确地为用户推荐兴趣相似的好友。     

一种综合LBS和社会网络标签的个性化推荐方法

针对现有的基于LBS(Location Based Service)个性化推荐系统在构建用户兴趣模型时存在的缺陷,提出一种综合LBS和社会网络标签的个性化推荐(LTCF)方法。通过引入网络标签和用户社会关系,从用户标注的标签资源中找到拥有共同兴趣爱好的用户关系以及从社会网络中找到与目标用户关系紧密的用户,同时结合考虑用户兴趣爱好随空间不断变化的特点,依据协同过滤算法,计算用户社会关系度和用户空间相似性,依此得到目标用户的最近邻集合,在最近邻集基础上给出推荐结果。实验结果表明,相比于传统的基于LBS推荐方法,LTCF模型在查全率和产准率有了显著的提升,能更好地反映出用户偏好,显著提高了推荐准确度。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate