关于 1000W 以上大功率家用真空吸尘器产品配套性效率指标的探讨——修订 QB1562-92 真空吸尘器标准的建议之二

该文试图从１０００Ｗ以上大功率家用真空吸尘器产品配套性原理出发,提出大功率机型效率建议指标,进一步完善ＱＢ１５６２－９２真空吸尘器标准的思路。     

基于贝叶斯信息准则的文本主题数估计

特定领域的主题识别和关键词提取有着广泛的应用,但通过人工指定识别或文本聚类自动生成的主题类别缺乏客观的度量方法。该文结合基于BIC准则的模型选择理论和独立分量分析技术对主题的数量进行概率估计,给出主题数量在BIC意义下的统计分布。在此基础上实现了文档矩阵的ICA分解,并根据分离的独立分量获得主题的关键词及其权重。实验表明,该方法在没有领域知识支持的情况下能估计出反映文本集合的主题数并提取相应的关键词。     

影响儿童通学需求层次的街道空间质量标准探究

街道空间承载儿童通学出行与社会性活动,对其健康成长产生重要影响。文章首先以儿童通学需求层次为出发点,对关联儿童出行和活动的公共/街道空间相关文献进行系统检索,确立了街道空间质量标准生成的理论依据。然后,以“12项公共空间质量标准”为基础架构,以“哥本哈根公共空间参数”为主要补充,对其他质量标准和设计特征进行整合操作,生成了包括4个大类、18个子项的街道空间质量标准框架。最后,基于它们与儿童通学具体需求之间互动关系的综合讨论,完成了相应指标因子的提取,构建出了一个较为完整的街道空间质量标准。可以作为学校周边街道空间更新过程中前期策划、中期设计和后期评估的辅助工具。     

机械密封的相似准数

主要介绍机械密封设计和使用的实践中用的相似准数。着重讨论最常用的相似准数，对有些相似准数有各种不同的看法和概念不清之处进行讨论。文中列出机械密封中常用的一般的相似准数和特殊的相似准数（简单与复合数群），可供密封工作者使用     

纤维水泥板和硅钙板生产线主机设备安装方案优化探讨

介绍了纤维水泥板和硅酸钙板生产线主机设备安装的重点,按照纤维水泥板和硅酸钙板产品特点,力求在安装阶段就按照正确的方式进行,减少因安装误差过大造成的返工及废料损失,规范纤维水泥板和硅酸钙板行业主机设备安装程序.     

城市韧性:基于国际文献综述的概念解析

城市韧性作为新兴的城市研究热点议题,其实质在于针对现代都市所面临的不确定性扰动,主动探索适应性的调整方法和途径。韧性的概念自源起以来,经历了从工程韧性,到生态韧性,再到演进韧性两次决定性的认知转型,形成了支撑现代城市韧性观点的支柱。本文通过全面回顾总结国际学界的相关文献,比较了三种韧性认知角度的本质区别,阐述了韧性城市研究的内容框架,并提出了与此相应的特征和评价标准。在此基础上,本文认为城市韧性是建立在传统规划理论上的指导现代城市可持续发展的全新途径。准确地把握城市韧性的概念内涵、内容框架和特征标准对于增强现代城市的适应能力具有重要的指导价值。     

Development of a Master Plan for Water Pollution Control Using MCDM Techniques: A Case Study

Abstract

Excessive demand for water due to a growing population, agricultural, and industrial development, along with climate change and depletion of nonrenewable resources have intensified the need for integrated water resources management and water pollution control. This paper presents different aspects of a master plan for water pollution control and the results of a case study for developing a master plan for water resources pollution control in Isfahan Province in Iran. Different components of the water resources system and pollution sources in the study area were identified and the effects of each of the pollution sources on surface and groundwater resources contamination were investigated. Two Multiple Criterion Decision Making (MCDM) techniques, namely Simple Additive Weighting (SAW) method and Analytical Hierarchy Structure (AHP) were used in order to determine the share of agricultural, industrial, and domestic sectors in polluting the water resources. In the application of MCDM techniques, engineering judgments and the information gathered from brain storming sessions with engineering experts and the agencies' officials have also been incorporated in order to overcome the data deficiency in this region for this type of analysis. Based on this study, several specific major categories of water pollution reduction projects were defined and in each category, several projects were identified. The total cost of implementation of the projects was also estimated and the projects were prioritized based on their potential impact on water pollution control.