Predicting social cues during online discussions: Effects of evaluations and knowledge content

This study examined whether evaluations (agreements, disagreements), knowledge content (new ideas, justifications), or social cues (SCs) in recent messages affected a current message’s positive or negative SC during asynchronous, online discussions. Using statistical discourse analysis, we modeled 894 messages by 183 participants on 60 high school mathematics topics (typically eight people posted per topic) on a mathematics problem solving website not connected to any class or school. Results showed that recent agreements increased the likelihood of positive SC, whereas justifications reduced it. Disagreements increased the likelihood of negative SC, whereas new ideas reduced it. Meanwhile, recent positive or negative SCs did not affect the likelihood of a subsequent SC. Together, these results suggest that judicious use of positive SCs rather than negative SCs during disagreements can help students both construct knowledge and maintain social relationships.     

加速寿命试验方法及评估

加速寿命试验是为缩短试验时间,在不改变故障模式和故障机理的条件下,用加大应力的方法进行的试验。随着元器件水平的迅速提高,高可靠、长寿命的产品越来越多,在正常应力水平下进行寿命试验来评定产品的可靠性已不能满足实际需要,代价很高,不现实,目前广泛采用了加速寿命试验。本文介绍了加速寿命试验方法及评估,并给出了案例。     

基于统计推理的社区发现模型综述

社区有助于揭示复杂网络结构和个体间的关系.研究人员从不同视角提出很多社区发现方法,用来识别团内紧密、团间稀疏的网络结构.自2006年以来,提出了一些基于统计推理的社区发现方法,它们可识别实际网络中更多的潜在结构,并以其可靠的理论基础和优越的结构识别能力成为当前的主流.该类方法的主要目标是建立符合实际网络的生成模型以拟合观测网络,将社区发现问题转化为贝叶斯推理问题.首先给出社区发现中生成模型的相关定义;其次按照模型中社区组成元素将已有统计推理模型分为节点社区推理模型和链接社区推理模型,并深入探讨各种模型的设计思想及实现算法;再次,总结各模型适用的网络类型及规模、发现的社区结构、算法复杂度等,给出一种选择已有基于统计推理的社区发现模型的方法,并利用基准数据集对已有典型统计推理模型进行验证及分析;最后探讨了基于统计推理模型的社区发现存在的主要问题和未来发展的方向.     

Quality Management in Pakistan's Bedwear Industry

Pakistan's bedwear industry contributes significantly to Pakistan's industry in general and to its textile industrial output and exports in particular. The exports of bedwear have increased steadily. However, its key basis of competitive advantage has been low cost. After greater liberalization from 2005 onwards and due to tariffication of quotas, the bedwear industry will not only have to scale higher tariff walls but will be more exposed to the threat of anti-dumping duties as it relies primarily on low prices to penetrate the export markets. To enhance its competitiveness, it will have to combine better quality with low costs and quick response. Research in quality management in Pakistan's bedwear industry was, therefore, undertaken. A postal self-completion questionnaire was mailed to 38 members of Pakistan Bedwear Manufacturers' and Exporters' Association (PBMEA). The response rate was almost 79%. It was found that this industrial segment was in various stages of development. This study demonstrates both the effectiveness and the limits of quality assurance in improving the levels of quality which remain a moving target in a dynamic liberalizing international trade environment that is more competitive since 2005. The bedwear industry, therefore, needs to graduate to advanced practices in quality management in order to remain competitive in rapidly changing times.     

基于最大熵模型的汉语依存分析

采用最大熵模型实现中文依存语法的分析。用自底而上的方式构建语句的依存关系树，构建过程每一步在向左连接、向右连接以及不连接3种动作选取其一。用最大熵原理判断每个动作的概率，得到依存树中各边的概率，然后找出具有最大概率的依存关系树。实验结果表明，该模型具有较好的分析精度。目前，该模型已被应用于基于自然语言的信息检索项目中。     

轧机接轴扭矩动态测试信号分析及评价

目前，动态测试技术是用于设备效能判定的重要手段，尤其是在大型冶金，石油企业中，常常能够解决一些理论上无法解决的技术难题。本文通过对某轧钢厂3200轧机上下接轴扭矩信号的动态测试数据分析，总结了该轧机上下接轴扭矩变化规律，对于该轧机频繁发生的主传动系统十字轴断裂事故提供了可靠的依据，利于企业合理组织生产，优化轧制工艺，发挥轧机优势等。     

A Virtual System for Vision Based SPC

A virtual system for vision based SPC (Statistical Process Control) is explored and constructed in this article for the purpose of the preliminary tests. Its performance is compared with that of a real vision system in a case study. The similarity between the virtual and real systems is examined with a chi-square test and an X chart experiment. The results suggest that the virtual system can be used to replace the real system in the preliminary test. The virtual system has many advantages, such as low cost, easy setup, wide adaptability, and being heuristic in nature. The use of the virtual system may help promote the applications of vision system to SPC.     

Statistical Independence as Linear Independence

A contingency table summarizes the conditional frequencies of two attributes and shows how these two attributes are dependent on each other. Thus, this table is a fundamental tool for pattern discovery with conditional probabilities, such as rule discovery. In this paper, a contingency table is interpreted from the viewpoint of granular computing. The first important observation is that a contingency table compares two attributes with respect to the number of equivalence classes. The second important observation is that matrix algebra is a key point of analysis of this table. Especially, the degree of independence, rank plays a very important role in extracting a probabilistic model from a given contingency table.     

Object representation and recognition in shape spaces

In this paper, we describe a shape space based approach for invariant object representation and recognition. In this approach, an object and all its similarity transformed versions are identified with a single point in a high-dimensional manifold called the shape space. Object recognition is achieved by measuring the geodesic distance between an observed object and a model in the shape space. This approach produced promising results in 2D object recognition experiments: it is invariant to similarity transformations and is relatively insensitive to noise and occlusion. Potentially, it can also be used for 3D object recognition.     

Linear transform for simultaneous diagonalization of covariance and perceptual metric matrix in image coding

Two types of redundancies are contained in images: statistical redundancy and psychovisual redundancy. Image representation techniques for image coding should remove both redundancies in order to obtain good results. In order to establish an appropriate representation, the standard approach to transform coding only considers the statistical redundancy, whereas the psychovisual factors are introduced after the selection of the representation as a simple scalar weighting in the transform domain.In this work, we take into account the psychovisual factors in the definition of the representation together with the statistical factors, by means of the perceptual metric and the covariance matrix, respectively. In general the ellipsoids described by these matrices are not aligned. Therefore, the optimal basis for image representation should simultaneously diagonalize both matrices. This approach to the basis selection problem has several advantages in the particular application of image coding. As the transform domain is Euclidean (by definition), the quantizer design is highly simplified and at the same time, the use of scalar quantizers is truly justified. The proposed representation is compared to covariance-based representations such as the DCT and the KLT or PCA using standard JPEG-like and Max-Lloyd quantizers.