基于P2P的云计算模型及其安全性分析

文章通过将P2P技术和云计算相结合,提出了一种可靠的、可扩展的、低成本的文件共享模型PA-Cloud。该文介绍了PA-Cloud的文件下载和更新过程,并对系统的安全性进行了分析。通过对PA-Cloud进行对比实验表明,PA-Cloud可以有效提高系统的可扩展性,降低服务提供商的成本。     

防爆变频器在煤矿应用中的关键技术

分析了防爆变频器在煤矿井下使用过程中存在的电压等级、散热、电磁兼容性、逆变器转换效率等问题,详细介绍了解决这些问题的方法,即通过采用隔爆兼本质安全型技术和热管散热技术解决变频器的防爆和散热问题,使防爆变频器具有性能高、功能强、噪音低等特点;通过改变变频器的电路拓扑结构、改进控制策略等技术手段解决变频器的电磁兼容性和能耗问题,使防爆变频器满足煤矿生产的现代化要求。     

Feature extraction using orthogonal discriminant local tangent space alignment

A novel algorithm called orthogonal discriminant local tangent space alignment (O-DLTSA) is proposed for supervised feature extraction. Derived from local tangent space alignment (LTSA), O-DLTSA not only inherits the advantages of LTSA which uses local tangent space as a representation of the local geometry so as to preserve the local structure, but also makes full use of class information and orthogonal subspace to improve discriminant power. The experimental results of applying O-DLTSA to standard face databases demonstrate the effectiveness of the proposed method.     

Design and implementation of a confidentiality and access control solution for publish/subscribe systems

The publish/subscribe model offers a loosely-coupled communication paradigm where applications interact indirectly and asynchronously. Publishers generate events that are sent to interested applications through a network of brokers. Subscribers express their interest by specifying filters that brokers can use for routing the events. Supporting confidentiality of messages being exchanged is still challenging. First of all, it is desirable that any scheme used for protecting the confidentiality of both the events and filters should not require publishers and subscribers to share secret keys. In fact, such a restriction is against the loose-coupling of the model. Moreover, such a scheme should not restrict the expressiveness of filters and should allow the broker to perform event filtering to route the events to the interested parties. Existing solutions do not fully address these issues. In this paper, we provide a novel scheme that supports (i) confidentiality for events and filters; (ii) allows publishers to express further constraints about who can access their events; (iii) filters that can express very complex constraints on events even if brokers are not able to access any information in clear on both events and filters; (iv) and, finally, it does not require publishers and subscribers to share keys. Furthermore, we show how we applied our scheme to a real-world e-health scenario, developed together with a hospital. We also describe the implementation of our solution in Java and the integration with an existing publish/subscribe system.     

基于视差与分层渲染的立体显示效果评价研究

本文在充分分析国内外立体显示技术评价方法的基础上,提出了利用视差和分层渲染的方法进行立体显示效果的评价,结果表明其对于自由立体显示评价可以得到较明确的分析结果,最后对研究前景进行了必要的探讨。     

基于检索决策树的螨种分类鉴定专家系统

应用传统的分类检索方法进行粉螨亚目螨种的分类鉴定是一个复杂、繁琐的过程。随着人工智能技术的发展,采用专家系统技术编制螨种分类鉴定软件将改变传统的分类鉴定方式。通过学习粉螨亚目的分类学和专家系统的相关知识,将螨种的分类鉴定与专家系统有机地结合起来,采用面向对象方法,设计并实现了基于决策树的螨种分类鉴定专家系统。通过构建基于面向对象的决策树知识表示模型,提炼出螨种知识库的记录结构,根据节点对象的逻辑关系,设计了基于决策树的推理机制,并按照一定的推理控制策略实现了螨种的分类鉴定。结果证明,满足了用户的需要,具有重要的实践价值。     

基于DSP+CPLD的车牌实时识别系统的设计

传统的基于微机的车牌识别系统的方案,使得评价识别效果的识别速率和识别成功率两个重要指标相互冲突.为了解决这个问题,很多文章提出了改进算法来调和识别算法的计算量和识别的成功率,但却没有考虑识别系统的成本问题.提出了一个基于DSP CPLD的硬件识别平台,可以大大提高各种识别算法的适应性和降低系统成本.     

Alcohol consumption detection through behavioural analysis using intelligent systems

We describe in this paper a new methodology for blood alcohol content (BAC) estimation of a subject. Rather than using external devices to determine the BAC value of a subject, we perform a behaviour analysis of this subject using intelligent systems. We monitor the user’s actions in an ordinary task and label those data to various measured BAC values. The obtained data-set is then used to train learning systems to detect alcoholic consumption and perform BAC estimation. We obtain good results on a mono-user base, and lower results with multiple users. We improve the results by combining multiple classifiers and regression algorithms.     

PVA-based activated carbon fibers with lotus root-like axially porous structure

A novel method was developed for the fabrication of activated carbon fiber (ACF) with wet spinning polyvinyl alcohol (PVA) fibers as the precursors. Through a combination of preoxidation, dehydration, carbonization and activation under a certain tension, PVA-based ACFs (PVA-ACFs) with high yields and good mechanical properties were obtained. The surface and cross-section morphologies, pore structures, surface geometries, surface functional groups and crystal structures of the PVA-ACFs were characterized using field emission scanning electron microscopy, low temperature nitrogen adsorption, Fourier transformed infrared spectrophotometry, X-ray photoelectron spectroscopy and X-ray power diffraction. All the PVA-ACF samples prepared had lotus root-like axially meso- and macroporous structures with the domination of micropores. Fractal geometries of PVA-ACFs deduced from nitrogen adsorption isotherms indicates that capillary force dominated in the interactions between nitrogen and the PVA-ACFs. The surface functional groups of the PVA-ACFs depend on the activating agents. Graphitoidal crystal structures were observed for the PVA-ACFs. The small crystal size and short range ordering between the crystallites ensured a high specific surface area of the PVA-ACFs.