无线传感器网络中一种高效IBE方案

无线传感器网络的应用日益广泛但安全性问题越发突出,由于其计算能力、存储能力和通信能力有限,一直被认为不适合使用公钥密码学方案。然而近年来不需要认证中心的IBE算法的研究成果表明,IBE方案非常适合无线传感器网络。本文提出一种高效的IBE方案,并做了算法介绍,同时在无线传感器网络中提出相应的密钥分配、认证、管理以及更新的应用方案。与现有其他算法相比,新方案具有系统参数短、安全性高等特点。     

On the implication problem for cardinality constraints and functional dependencies

In database design, integrity constraints are used to express database semantics. They specify the way by that the elements of a database are associated to each other. The implication problem asks whether a given set of constraints entails further constraints. In this paper, we study the finite implication problem for cardinality constraints. Our main result is a complete characterization of closed sets of cardinality constraints. Similar results are obtained for constraint sets containing cardinality constraints, but also key and functional dependencies. Moreover, we construct Armstrong databases for these constraint sets, which are of special interest for example-based deduction in database design.     

The impact of status and audio conferencing technology on business meetings

This field study examining the effects of organizational status and multimedia audio communications technology on communication patterns in business meetings confirms that high status group members verbally dominate discussions and have more control over the flow of the proceedings. However, it reveals a new and surprising finding: multimedia communications technology can in fact exaggerate status constraints in contrast to findings that there is no effect or an equalizing effect on status inequalities of text-based conferencing technology. It appears that in audio conferences, the lack of non-verbal cues that can aid turn-taking combined with (1) the participants' knowledge of the group's status hierarchy and (2) the tendency to compare oneself unfavourably to those of higher status, makes it more difficult for lower status individuals to contribute verbally to discussions than in face-to-face interactions. Such status constraints may have both positive and negative impacts on group communication effectiveness, these and implications for the design and implementation of multimedia communications technology are discussed.     

出境台湾游客旅游目的地选择关键因素之分析

游客选择不同旅游目的地的群体行为客观存在。这种游客对目的地的选择受多种因素影响,影响程度也大小不同。文章提出出境游客目的地选择四大关键因素的假设,并以出境台湾游客为研究对象,收集、计算台湾游客在23个目的地空间分布以及交通联系指数、旅游资源丰度、对外关系度、贸易依存度的数据,采用最小二乘估计法（0LS）建立多元线性回归模型,分析空间距离、资源禀赋、对外关系、经济贸易对出境台湾游客目的地选择影响。结果显示,台湾游客的出访率与交通联系指数、贸易依存度呈正相关关系,交通、经贸直接影响出境台湾游客对目的地的选择;但与旅游资源丰度、对外关系度呈略微负相关关系,资源禀赋、对外关系并不影响出境台湾游客对目的地的选择。     

我国功率型LED产业化关键技术

本文介绍了我国功率型LED产业链三个阶段的关键技术。     

右江百色重力坝消力池结构缝键槽布置方案优化研究

采用数值方法模拟键槽传剪传压不传拉的工作机理,通过对建于不均匀地基上的百色消力池开展三维整体有限元分析,对比研究键槽布置方式对消力池底板应力与变形的影响,结果表明地基的不均匀性使消力池各板块间产生不均匀沉降及错台现象,键槽的设置可以明显消除这种现象,但在基础弹模、重量和块度相差悬殊的板块之间不宜设置键槽以避免产生过大的键槽剪应力。     

Capturing Attention When Attention "Blinks".

Four experiments addressed the question of whether attention may be captured when the visual system is in the midst of an attentional blink (AB). Participants identified 2 target letters embedded among distractor letters in a rapid serial visual presentation sequence. In some trials, a square frame was inserted between the targets; as the only geometric object in the sequence, it constituted a singleton. Capture effects obtained when the AB was most severe and when it was over were compared. There were 3 main results. First, capture occurred even when the AB was crippling, suggesting that a singleton exogenously engaged attention even when processing of a previous target was continuing apace. Second, when the singleton contained the key target feature, capture effects were clearly manifest. Third, even when the singleton did not possess the key target feature, it still succeeded in capturing attention, although the effects were both feeble and fleeting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

丹东市个体私营经济发展态势分析

我市个体私营经济具有一定的经济基础,发展前景广阔,渐趋成为全市经济的重要组成部分。本文阐述了我市个体私营经济的现状,分析了发展中存在的问题,提出了加快发展所应采取的措施。     

集成式计算机协同工作(CSCW)支持环境的研究与实现

提出了一种构造集成式计算机支持的协同工作（ＣＳＣＷ）支持环境的解决方案,介绍了集成机制的原理、消息机制与挂接机制的结合和应用,以及ＣＳＣＷ支持环境的设计与实现技术．讨论了相关问题,提出并实现了改进方案．同时,也介绍了集成式ＣＳＣＷ支持环境与视频会议系统的结合．     

外装门锁钥匙插拔卡滞问题检测与分析

针对新安装门锁钥匙插拔卡滞而打开困难的问题,在SG17-03型钥匙拔出力测试仪上进行了钥匙拔出力测试.介绍了门锁检测过程,分析了门锁钥匙插拔卡滞原因,通过解体检验及拔出力测试提出了解决办法.