基于模式识别理论的内燃机状态识别研究

用模式识别的理论和方法，对内燃机气门间隙的识别问题进行了探讨。在分析气门振动力学模型的基础上，通过测取振动信号获得故障特征信息，用模式识别的理论和方法，在建立状态特征模式空间的基础上实现对故障的分类识别。考虑到内燃机振动信号的复杂性，采用了外触发采样和有效截取的方法进行信号的数据采集和分析。     

WWW检索工具比较研究

近年来,随着ＷＷＷ技术的广泛应用,使得Ｉｎｔｅｒｎｅｔ迅速发展。作为Ｉｎｔｅｒｎｅｔ网上的信息查找途径,ＷＷＷ检索站点已成为Ｉｎｔｅｒｎｅｔ网上最繁忙的站点之一。本文选取了Ｙａｈｏｏ、ＡｌｔａＶｉｓｔａ、Ｅｘｃｉｔｅ、ＨｏｔＢｏｔ、Ｉｎｆｏｓｅｋ、Ｌｙｃｏｓ、ＯｐｅｎＴｅｘｔ、ＷｅｂＣｒａｗｌｅｒ及ＭｅｔａＣｒａｗｌｅｒ等九个著名的ＷＷＷ检索工具,通过上网实验,分析比较各工具检索引擎的特点,并从用户角度指出检索引擎现阶段存在的问题。最后对开发我国的ＷＷＷ检索工具提出了建议     

地热电站凝汽器真空系统的技术经济性分析

本文分析了真空系统对地热电站高效运行的重要意义,介绍了射汽抽气器及水环式真空泵两类真空系统的工作原理,并基于肯尼亚某地热井井口电站参数,对两级抽气器和两级水环式真空泵的当量能耗进行了技术经济性对比分析,给出了地热电站真空系统优选建议,为真空系统的优化提供了科学依据。     

The Future Development of Energy-Environment-Economy Integrated Assessment Modelling

<正>One of the greatest challenges faced by the energy and economic system is the risk of environmental and climate change.The models that have been developed to study the principle and dynamics of the energy,environment,and economic system are called the     

ClinicalAccess: A Clinical Decision Support Tool

ClinicalAccess is a new clinical decision support tool that uses a question-and-answer format to mirror clinical decision-making strategies. The unique format of ClinicalAccess delivers concise, authoritative answers to more than 120,000 clinical questions. This column presents a review of the product, a sample search, and a comparison with other point-of-care search engines.     

油冷柴油机及其余热回收系统

本文介绍一种可以节约燃油的方法。该方法利用油冷却船用柴油机的气缸盖、气缸套及其它部件,并使气缸盖出口处冷却温度在大气压力下为100℃或更高。由于提高了冷却介质的出口温度,减少了热损失,增加余热回收,从而取得节油效果。     

Comparing rankings of search results on the Web

The Web has become an information source for professional data gathering. Because of the vast amounts of information on almost all topics, one cannot systematically go over the whole set of results, and therefore must rely on the ordering of the results by the search engine. It is well known that search engines on the Web have low overlap in terms of coverage. In this study we measure how similar are the rankings of search engines on the overlapping results.We compare rankings of results for identical queries retrieved from several search engines. The method is based only on the set of URLs that appear in the answer sets of the engines being compared. For comparing the similarity of rankings of two search engines, the Spearman correlation coefficient is computed. When comparing more than two sets Kendall’s W is used. These are well-known measures and the statistical significance of the results can be computed. The methods are demonstrated on a set of 15 queries that were submitted to four large Web search engines. The findings indicate that the large public search engines on the Web employ considerably different ranking algorithms.     

典型的图像搜索引擎特征和评价

本文首先介绍图像搜索引擎技术基础，并对图像搜索引擎进行分类；然后挑选网上较为典型的搜索引擎，分析它们的特点且给予扼要的评述。     

四种搜索引擎的比较研究

本文对目前常用的4种中文搜索引擎：Google、百度、天网、Openfind的索引数据库收录范围、检索功能、检索结果显示格式、用户界面等方面进行了比较分析，并指出它们各自的优势与不足。     

风管加湿系统节能改造的研究

通过对某现代化工厂的风管加湿系统进行分析,提出革新方案,并从技术和经济方面进行了对比分析,得出新方案更加有效和节能的结论,并且使得企业能够在短期内实现投资回报。