严格计算输运过程的2问题     

陈五立  杨红 《宜春学院学报》2006,(2)

本文利用参与定向运动动量输运的分子数是总分子数的16的假设,综合通过考虑分子的速度分布及分子从各个方向穿过dA面,阐述了一种既严格又简明计算输运过程无碰撞地穿过dA面的分子之平均自由程方法。  相似文献   

数字图书馆中基于内容的视频拷贝检测关键技术研究     

徐彤阳  张国标 《现代情报》2016,36(2):135-139

随着数字图书馆中数字视频资源的增长,数字视频版权保护问题逐渐暴露出来。基于内容的视频拷贝检测技术作为一种有效的版权保护技术,近年来逐渐受到研究人员的关注。本文对基于内容的视频拷贝检测的关键技术视频指纹提取和指纹匹配的研究成果进行了分析,总结了指纹提取和指纹匹配的研究现状,指出了该领域存在的问题,最后分析了该领域的发展方向。  相似文献   

Dependency structure language model for topic detection and tracking     

Changki Lee  Gary Geunbae Lee  Myunggil Jang 《Information processing & management》2007

In this paper, we propose a new language model, namely, a dependency structure language model, for topic detection and tracking (TDT) to compensate for weakness of unigram and bigram language models. The dependency structure language model is based on the Chow expansion theory and the dependency parse tree generated by a linguistic parser. So, long-distance dependencies can be naturally captured by the dependency structure language model. We carried out extensive experiments to verify the proposed model on topic tracking and link detection in TDT. In both cases, the dependency structure language models perform better than strong baseline approaches.  相似文献   

游戏平台入侵检测技术研究     

罗国权  郭伟  李东 《中国科技信息》2007,(19):97-99,101

网络安全问题是一个十分复杂的问题,涉及到电子商务、信息交换和游戏服务器。入侵检测与防御技术作为新一代网络信息安全保障技术,它主动地对网络信息系统中的恶意入侵行为进行识别和响应,不仅检测和防御来自外部网络的入侵行为,同时监视和防止内部用户未授权活动和误操作行为。本文提出了针对游戏服务器的入侵检测方案,在一定程度上缓解了黑客攻击游戏服务器的行为。  相似文献   

Topic discovery based on text mining techniques     

Aurora Pons-Porrata  Rafael Berlanga-Llavori  José Ruiz-Shulcloper 《Information processing & management》2007

In this paper, we present a topic discovery system aimed to reveal the implicit knowledge present in news streams. This knowledge is expressed as a hierarchy of topic/subtopics, where each topic contains the set of documents that are related to it and a summary extracted from these documents. Summaries so built are useful to browse and select topics of interest from the generated hierarchies. Our proposal consists of a new incremental hierarchical clustering algorithm, which combines both partitional and agglomerative approaches, taking the main benefits from them. Finally, a new summarization method based on Testor Theory has been proposed to build the topic summaries. Experimental results in the TDT2 collection demonstrate its usefulness and effectiveness not only as a topic detection system, but also as a classification and summarization tool.  相似文献   

新一代ICP-MS功能及其痕量元素检测新技术     

卢森锴  韦汉龙  韦永森 《桂林师范高等专科学校学报》2011,25(2):144-147

综述了ICP-MS仪器的基本原理、结构、发展应用概况及其新产品的功能特点;阐述了新一代ICP-MS在有色金属材料痕量元素检测分析中质谱干扰和非质谱干扰问题及其克服新技术。  相似文献   

Scientific community detection via bipartite scholar/journal graph co-clustering     

Chiara Carusi  Giuseppe Bianchi 《Journal of Informetrics》2019,13(1):354-386

This paper stems from the observation that researchers in different fields tend to publish in different journals. Such a relationship between researchers and journals is quantitatively exploited to identify scientific community clusters, by casting the community detection problem into a co-clustering problem on bipartite graphs. Such an approach has the potential of leading not only to the fine- grained detection of scholar communities based on the similarity of their research activity, but also to the clustering of scientific journals based on which are the most representative of each community. The proposed methodology is purely data-driven and completely unsupervised, and does not rely on any semantics (e.g. keywords or a-priori subjective categories). Moreover, unlike “flat” data structures (e.g. collaboration graphs or citation graphs) our bipartite graph approach blends in a joint structure both the researcher's attitude and interests (i.e., freedom to select the venue where to publish) as well as the community's recognition (i.e., acceptance of the publication on a target journal); as such may perhaps inspire further scientometric evaluation strategies. Our proposed approach is applied to the Italian research system, for two broad areas (ICT and Microbiology&Genetics), and reveals some questionable aspects and community overlaps in the current Italian scientific sectors classification.  相似文献   

论能力与检测     

张树俊 《安徽职业技术学院学报》2011,10(4):46-49,63

能力检测是人力资源管理的基本环节,每个人的能力都是由能力质与能力量两大要素构成的,所以对于职工能力水平要从质和量两个方面进行检测。同时,由于人的能力体现受活动内容及其环境的影响,所以能力检测必须围绕活动来进行,并考虑环境因素的影响。此外,能力检测的可信度受诸多因素的影响,所以在测量职工的能力时,应灵活选择检测方式,采取定性分析与定量分析相结合的方法,客观公正、实事求是地对人的能力进行整体的、辩证的分析,努力提高能力检测的可信度。  相似文献   

自动内容抽取中的中文事件标注     

张先飞  郭志刚  李弼程  孙显著 《情报学报》2011,30(1)

事件检测与描述(Event Detection and Characterization,EDC)自2005年作为自动内容抽取(Automatic ContentExtraction,ACE)评测的一个重要子任务出现以来,中文事件的标注、检测与描述越来越成为研究热点。本文就自动内容抽取中的中文事件标注进行详细、系统地研究,主要包括:在ACE会议定义中文事件相关概念的基础上,给出事件标注中事件的可标注内容,包括事件范围及事件触发词等;根据生活中的事件分类在人工事件标注中对EDC的事件进行类别划分及其子类的详细区分,以降低事件检测的复杂度;对每个事件类别(包括子类别)中构成事件的元素进行研究,综合事件类别及其元素信息完成中文事件的标注。本文的研究成果在中文文本信息抽取、自动摘要及主题检测与追踪中得到了很好的应用。  相似文献   

Position detection and vibration monitoring system using quad-cell optical beam power distribution     

Yasmine El-Ashi  Taha Landolsi  Rached Dhaouadi 《Journal of The Franklin Institute》2011,348(7):1435-1455

In this paper, we study the accuracy of an optical vibration sensing system using Gaussian beam analysis. The proposed optical system uses a He-Ne laser source whose Gaussian beam impinges on a quad-cell photodetector array. The normalized optical power for each cell is obtained through numerical simulation based on the well-known Gaussian beam optics formulation, as the beam scans the plane of the photodetectors due to vibration. The system detection principle lies upon finding a relationship between the power distribution of the quad-cell and the position of the beam centroid, which allows us to identify the characteristics of the vibration applied, such as direction, frequency and strength. The aspects of practical implementation and experimental limitations on the power distribution accuracy are discussed and the discrepancies with the theoretical results are presented.  相似文献