道路冻深计算方法的研究

本文以热传导理论建立的道路冻深计算方法为根据，提出了道路冻深简化式。通过试验研究，确定出简化式中的道路材料热物性参数ａ值，道路横断面参ｂ值以及道路湿度参数ｃ值。最后，介绍了简化式应用实例。     

某公司氧化铝生产过程中金属镓回收工艺浅析

某公司对氧化铝生产过程中的母液进行综合利用回收提取,通过对比此过程产物金属镓的传统回收工艺和离子交换树脂吸收工艺,认为采用高效率低成本的离子交换树脂吸收法作为提取工艺较为合适,并展望其经济和社会效益。     

基团物理温Yong图及其应用

基于物质由基团构成的观点,提出了基团物理温Yong的概念并绘了不同基团的物理温Yong图,利用此图可方便求出不同和质的物理Yong.     

MD5在数据库中实现数据完整性校验

数据库是信息系统中最重要的资源,数据库的安全将直接影响信息系统的安全,一旦数据库中的数据被非法篡改,将对整个信息系统构成不可弥补的破坏。对数据库中的数据进行完整性校验非常必要,采用MD5算法实现数据完整性校验,是一种方便有效的方法。     

建设防水施工与土建工程分析

分析防水施工与土建工程相互作用力。聚合物水泥基防水涂料前景及展望．     

堇青石/碳化硅复相陶瓷窑具抗氧化性能研究

本文对碳化硅、堇青石的优点整合制备碳化硅/堇青石复相陶瓷窑具,以力学性能变化为基础通过研究偏钒酸铵含量、金属硅粉含量、烧成温度等3个方面对堇青石/碳化硅复相窑具材料抗氧化性能进行研究分析,并通过X-射线衍射(XRD)分析,复相陶瓷窑具中并未有明显的氧化物如SiO2等杂质相出现。     

Discovering genres of online discussion threads via text mining

As course management systems (CMS) gain popularity in facilitating teaching. A forum is a key component to facilitate the interactions among students and teachers. Content analysis is the most popular way to study a discussion forum. But content analysis is a human labor intensity process; for example, the coding process relies heavily on manual interpretation; and it is time and energy consuming. In an asynchronous virtual learning environment, an instructor needs to keep monitoring the discussion forum from time to time in order to maintain the quality of a discussion forum. However, it is time consuming and difficult for instructors to fulfill this need especially for K12 teachers. This research proposes a genre classification system, called GCS, to facilitate the automatic coding process. We treat the coding process as a document classification task via modern data mining techniques. The genre of a posting can be perceived as an announcement, a question, clarification, interpretation, conflict, assertion, etc. This research examines the coding coherence between GCS and experts’ judgment in terms of recall and precision, and discusses how we adjust the parameters of the GCS to improve the coherence. Based on the empirical results, GCS adopts the cascade classification model to achieve the automatic coding process. The empirical evaluation of the classified genres from a repository of postings in an online course on earth science in a senior high school shows that GCS can effectively facilitate the coding process, and the proposed cascade model can deal with the imbalanced distribution nature of discussion postings. These results imply that GCS based on the cascade model can perform as an automatic posting coding system.     

An investigation of coopetitive pedagogic design for knowledge creation in Web-based learning

Information and communication technologies (ICTs) have created a supportive environment for collaborative learning at the expense of student motivation and engagement. This study attempts to explore the development of a productive learning atmosphere in the context of Web-based learning. An experiment is conducted with university-level students having homogenous background and coursework by applying heterogeneous pedagogies that create either competitive or collaborative learning atmospheres. The differences in learning atmosphere bring about variations in social presence and enjoyment of learning. The findings show that “coopetition” (defined as collaboration within the group and competition between groups) was the best learning strategy because competition and collaboration stimulated different types of knowledge growth in the knowledge-creation spiral. Competitive learning atmospheres encourage students to develop higher analytic skills, while collaborative learning atmospheres prompt students to demonstrate higher synthetic skills. Because both atmospheres contribute to learning, this study has found that combining both pedagogies in constructing a coopetitive learning atmosphere not only contributes to analytic and synthetic skills, but also raises the overall knowledge level. The findings pinpointed the importance of creating a learning environment that integrates ICTs, learners’ backgrounds, courseware, and pedagogic considerations in the process of increasing knowledge levels.     

Two novel feature selection approaches for web page classification

To help the growing qualitative and quantitative demands for information from the WWW, efficient automatic Web page classifiers are urgently needed. However, a classifier applied to the WWW faces a huge-scale dimensionality problem since it must handle millions of Web pages, tens of thousands of features, and hundreds of categories. When it comes to practical implementation, reducing the dimensionality is a critically important challenge. In this paper, we propose a fuzzy ranking analysis paradigm together with a novel relevance measure, discriminating power measure (DPM), to effectively reduce the input dimensionality from tens of thousands to a few hundred with zero rejection rate and small decrease in accuracy. The two-level promotion method based on fuzzy ranking analysis is proposed to improve the behavior of each relevance measure and combine those measures to produce a better evaluation of features. Additionally, the DPM measure has low computation cost and emphasizes on both positive and negative discriminating features. Also, it emphasizes classification in parallel order, rather than classification in serial order. In our experimental results, the fuzzy ranking analysis is useful for validating the uncertain behavior of each relevance measure. Moreover, the DPM reduces input dimensionality from 10,427 to 200 with zero rejection rate and with less than 5% decline (from 84.5% to 80.4%) in the test accuracy. Furthermore, to consider the impacts on classification accuracy for the proposed DPM, the experimental results of China Time and Reuter-21578 datasets have demonstrated that the DPM provides major benefit to promote document classification accuracy rate. The results also show that the DPM indeed can reduce both redundancy and noise features to set up a better classifier.     

A new electronic traveler’s check scheme based on one-way hash function

Nowadays, electronic commerce is booming on the Internet and becoming more popular. Many kinds of electronic services have been developed. The most successful are the electronic payment systems such as the electronic cash/check and wallet. Most electronic payment systems are based on an elaborate discrete logarithm that raises an important issue regarding efficiency. Therefore, Hsien et al. proposed an electronic traveler’s check system in 2001 using a discrete logarithm. In this paper, we propose a new electronic traveler’s check system based on one-way hash function to improve efficiency and cost. Furthermore, our proposed scheme supports an on-line and off-line electronic traveler’s check system of practical flexibility for use in the real world.