丁基橡胶及卤化丁基橡胶市场分析

根据国内外丁基橡胶和卤化丁基橡胶现状，分析了未来几年的市场需求情况，并对国内丁基橡胶工业的发展提出了建议。     

岩盐钻井水溶双井连通开采工艺的研究与推广

文章就全国井矿盐采区多年的开采工艺技术，进行了系统的研究与总结，并提出了岩盐钻井水溶开采双井连通的各种开采工艺及其关键技术，具有很强的适用性和推广价值。     

Extensions of LDA by PCA mixture model and class-wise features

Linear discriminant analysis (LDA) is a data discrimination technique that seeks transformation to maximize the ratio of the between-class scatter and the within-class scatter. While it has been successfully applied to several applications, it has two limitations, both concerning the underfitting problem. First, it fails to discriminate data with complex distributions since all data in each class are assumed to be distributed in the Gaussian manner. Second, it can lose class-wise information, since it produces only one transformation over the entire range of classes. We propose three extensions of LDA to overcome the above problems. The first extension overcomes the first problem by modelling the within-class scatter using a PCA mixture model that can represent more complex distribution. The second extension overcomes the second problem by taking different transformation for each class in order to provide class-wise features. The third extension combines these two modifications by representing each class in terms of the PCA mixture model and taking different transformation for each mixture component. It is shown that all our proposed extensions of LDA outperform LDA concerning classification errors for synthetic data classification, hand-written digit recognition, and alphabet recognition.     

硫在铅熔炼过程中的行为分析

介绍了铅烧结焙烧-鼓风炉还原熔炼过程中硫的分布及存在形态，着重分析了混合料含硫量与结块率的关系，得出了混合料含硫的临界值。论述了烧结块中残留的硫离子及硫酸根离子对铅熔炼生产的影响。针对硫的不同存在形态，提出了有效的解决办法和改进措施。     

Profile-Based Linguistic Uniformity as a Generic Method for Comparing Language Varieties

In this text we present``profile-based linguistic uniformity', a methoddesigned to compare language varieties on thebasis of a wide range of potentiallyheterogeneous linguistic variables. In manyrespects a parallel can be drawn with currentmethods in dialectometry (for an overview, see,Nerbonne and Heeringa, 2001; Heeringa, Nerbonneand Kleiweg, 2002): in both casesdissimilarities between varieties on the basisof individual variables are summarized inglobal dissimilarities, and a series oflanguage varieties are subsequently clusteredor charted using multivariate techniques suchas cluster analysis or multidimensionalscaling. This global similarity between themethods makes it possible to compare them andto investigate the implications of notabledifferences. In this text we specifically focuson, and defend one characteristic of ourmethodology, its profile-based nature.     

Hybrid Approach for Addressing Uncertainty in Risk Assessments

Parameter uncertainty is a major aspect of the model-based estimation of the risk of human exposure to pollutants. The Monte Carlo method, which applies probability theory to address model parameter uncertainty, relies on a statistical representation of available information. In recent years, other uncertainty theories have been proposed as alternative approaches to address model parameter uncertainty in situations where available information is insufficient to identify statistically representative probability distributions, due in particular to data scarcity. The simplest such theory is possibility theory, which uses so-called fuzzy numbers to represent model parameter uncertainty. In practice, it may occur that certain model parameters can be reasonably represented by probability distributions, because there are sufficient data available to substantiate such distributions by statistical analysis, while others are better represented by fuzzy numbers (due to data scarcity). The question then arises as to how these two modes of representation of model parameter uncertainty can be combined for the purpose of estimating the risk of exposure. This paper proposes an approach (termed a hybrid approach) which combines Monte Carlo random sampling of probability distribution functions with fuzzy calculus. The approach is applied to a real case of estimation of human exposure, via vegetable consumption, to cadmium present in the surficial soils of an industrial site located in the north of France. The application illustrates the potential of the proposed approach, which allows the uncertainty affecting model parameters to be represented in a way that is consistent with the information at hand. Also, because the hybrid approach takes advantage of the “rich” information provided by probability distributions, while retaining the conservative character of fuzzy calculus, it is believed to hold value in terms of a “reasonable” application of the precautionary principle.     

网络环境下高校图书馆期刊资源建设与发展

本文根据电子期刊的定义、特点及图书馆期刊工作所需要面对的问题，就高校图书馆网络环境下期刊工作的设施规划、资料收集、信息开发及读者培训等多方面内容进行了简单探讨，并就如何应对网络环境下图书馆期刊工作的变化提出建议。     

Safe and effective navigation of autonomous robots in hazardous environments

The development of autonomous mobile machines to perform useful tasks in real work environments is currently being impeded by concerns over effectiveness, commercial viability and, above all, safety. This paper introduces a case study of a robotic excavator to explore a series of issues around system development, navigation in unstructured environments, autonomous decision making and changing the behaviour of autonomous machines to suit the prevailing demands of users. The adoption of the Real-Time Control Systems (RCS) architecture (Albus, 1991) is proposed as a universal framework for the development of intelligent systems. In addition it is explained how the use of Partially Observable Markov Decision Processes (POMDP) (Kaelbling et al., 1998) can form the basis of decision making in the face of uncertainty and how the technique can be effectively incorporated into the RCS architecture. Particular emphasis is placed on ensuring that the resulting behaviour is both task effective and adequately safe, and it is recognised that these two objectives may be in opposition and that the desired relative balance between them may change. The concept of an autonomous system having “values” is introduced through the use of utility theory. Limited simulation results of experiments are reported which demonstrate that these techniques can create intelligent systems capable of modifying their behaviour to exhibit either ‘safety conscious’ or ‘task achieving’ personalities.     

Allowables-Based Flow Curves for Nonlinear Finite-Element Analysis

A methodology for developing allowables-based stress versus strain relationships for metal alloys is presented. The approach incorporates Federal Aviation Administration/Department of Defense (FAA/DoD) Metallic Materials Property Development and Standardization (MMPDS) statistically derived material properties for tensile yield and ultimate strengths to derive flow curves at room or elevated temperature with an A-, B-, or S-Basis probability. The resulting flow curves may be used for new designs to comply with Federal Air Regulations as well as for forensic investigations and failure analysis.     

电厂热力系统耗差分析系统实现的研究与发展

总结了电厂热力系统耗差分析几种实现方式，回顾了国内在该领域的发展过程。电厂热力系统耗差分析实现方式分别经历了独立的耗差分析系统、基于DCS的耗差分析系统、基于MIS的耗差分析系统。并在不同的分析方式上进行了评价，指出了耗差分析系统的发展方向。