WWW上路径模式发掘的研究

本文从互连网发展的趋势入手,对路径模式发掘进行了研究。先简要介绍数据库发掘的概况及网上数据发掘的特点,后结合关联法和组合概率法,并以算法和实例详细对之进行分析。     

High-pressure plastic flow in silicon: A first-principles theoretical study

Summary Microindentation experiments have recently shown that silicon can exhibit plastic flow when subjected to high pressure. Assuming that under these conditions the relevant reference structure is the -Sn high-pressure phase of silicon, we apply the magic-strain concept to explore the space of configurations that could describe the observed behavior. We use first-principles total-energy calculations (including full relaxation of the atomic basis for every structure) to evaluate the relevance of strained configurations. Using this approach, we were able to identify a low-energy path that corresponds to planar flow of the atoms. The atomic configurations along this path provide insight into possible microscopic motions under high pressure that may be relevant to plastic flow in silicon.     

Organized knowledge sharing with book-centered Web sites: An architecture, implementation and analysis

For educators, the World Wide Web offers a valuable technology for knowledge sharing. It can complement more traditional approaches to knowledge sharing such as books and lectures. Here, we identify and differentiate three major approaches for Web-based knowledge sharing: course-centered sites, subject-centered sites, and book-centered sites. A rationale for book-centered sites, those developed to facilitate students’ and instructors’ efforts in courses that use the book, is advanced. We introduce an architecture of features that can guide developers of such sites. This is illustrated by a book-centered site implemented according to the architecture. Several sites for introductory business computing books are compared and contrasted in terms of the architecture, suggesting ways in which each can be extended. This revised version was published online in July 2006 with corrections to the Cover Date.     

食用级碱式碳酸镁生产工艺研究

研究了以工业级硫酸镁为原料生产食用级碱式碳酸镁的工艺条件及影响产品收率的主要因素。     

溪洛渡水电站拱坝施工期坝基变形监测分析

为了解溪洛渡水电站拱坝坝基在施工期、蓄水初期及运行期不同阶段的变形情况和工作状态,确保大坝安全,同时为给工程建设及运行期管理提供科学依据,对坝基垂直位移和水平位移进行了监测,并对监测资料进行了初步分析.监测结果表明拱坝坝基沉降变形比较均匀,变化规律正常.     

Using standards to integrate soft real-time components into dynamic distributed architectures

A pervasive application domain today is one in which independently developed real-time components participate in a dynamic and decentralized way from distributed environments. Several challenges arise from this domain, related with participant heterogeneity, transient behavior, scalability or quality of service. The use of standards is important here, where a multidiscipline approach is required. We propose ServiceDDS, a framework that combines different standard technologies to solve the problems related with the integration of components into the described environment. ServiceDDS is based on DDS to support dynamic distributed interactions, XMPP to provide Web access, and RTSJ for real-time performance.     

Extending UML to model Web 2.0‐based context‐aware applications

Web 2.0 Mashups offer entirely new opportunities for context‐aware application (CAA) developers by integrating Web 2.0 technologies to facilitate interoperability among heterogeneous context‐aware systems. From a software engineering perspective, a visualized approach for Web 2.0‐based CAA modeling is crucial. Current CAA development, however, cannot provide a conceptual model for Web 2.0‐based CAA. Therefore, the development efficiency and potential for reuse are decreased. The UML is a general purpose modeling language with potential for use in many application domains. However, UML often lacks elements needed to model concepts in specific domains, such as Web 2.0‐based CAA modeling. To address the above issues, this study presents the Web 2.0‐based CAA UML profile, a UML profile for modeling Web 2.0‐based CAA. Copyright © 2011 John Wiley & Sons, Ltd.     

Measuring task-specific perceptions of the world wide web

This paper describes the development of multi-item scales for measuring user perceptions of the ease-of-use and usefulness of the Web (hereafter web), incorporating a system task focus into the scales dimensional structure (e.g. how easy or useful the web is for information search, communication and or purchasing). The items are tested on 2077 web users recruited using a web survey, revealing four factors for each scale. Perceived ease-of-web use consists of learning, search and find, transaction and communication ease, and perceived web usefulness consists of communication, purchase, information search and acquisition, and access to quality products and information. A regression analysis on web usage frequency shows how easy users find it to learn how to use the web and how useful the web is for purchasing are the best predictors of how frequently they will use the web. These results highlight the importance of training users how to effectively use hypermedia-based systems like the web, and the design of systems that are easy to navigate and that provide advanced functionality for transactional activity.     

砂土的剪胀方程及其塑性势(Ⅰ):发展现状

以能量守恒原理为主线,在各向同性前提下,对Taylor剪胀方程、Cam-clay剪胀方程、修正Cam-clay剪胀方程、Rowe剪胀方程和扩展的Rowe剪胀方程等进行了较全面的综述.论证了剪胀方程和塑性势函数之间的相互转化关系.指出了Lade-Kim塑性势函数和Nova塑性势函数的缺陷之处,即这两个塑性势函数均没有合理耦合临界状态这一概念.     

造粒机模板与切粒刀对聚乙烯颗粒质量的影响

通过多年来对聚乙烯造粒系统的调查研究及现场实践，确认了聚乙烯产品质量的影响因素。选择了造粒模板与切粒刀之间的最佳匹配。