车辆制动性能的不确定性分析

采用不确定性方法对车辆制动过程中的随机参数进行了分析。针对制动过程中的瞬时车速以及最大制动力建立可靠性模型,将随机理论和随机摄动技术引入到车辆制动性能分析,利用不确定性理论给出了分析结果的置信区间和置信度,提高了车辆制动性能分析的准确度。与蒙特卡洛随机模拟方法得到的计算结果进行对比,验证了本文方法的正确性和准确性。     

Media and the Imaginary in History

This paper discusses how media theory and history should approach specimens of evidence about the cultural reception of media pertaining to the realms of the fantastic, such as speculations, predictions, dreams, and other forms of fantasy regarding media. It argues that the role of the imaginary in the history of media can be fully comprehended only by employing a perspective which is dynamic in time. In different phases of a medium's evolution, in fact, we find different fantasies; it follows that we need specific approaches to study them. The article discusses fantasies which are specific to three stages in media change: those preceding the actual invention of a medium; those accompanying the earliest period after the introduction of a new medium; and those connected to old media.     

Thinking with a Theory: Theory-prediction Consistency and Young Children’s Identification of Causality

Theory-testing can only inform scientific inquiry when the prediction of test outcome is based upon the current theory (theory-prediction consistency). This investigation explores children’s theory-prediction consistency in a computer-mediated task in which multiple opportunities were provided to predict outcomes and review theories. An initial correlation study revealed that theory-prediction consistency was associated with children’s success when attempting to identify causation. The second study investigated the effect of goal and a simple intervention upon children’s theory-prediction consistency. The type of goal appeared to have no effect but the intervention, which encouraged the children to use their theory to make predictions, significantly improved their ability to identify cause. Interestingly, it also improved other aspects of their performance – such as encouraging more reflection upon the outcomes of tests. The results imply that poor theory-prediction consistency may be related to difficulties in identifying the type of problem being presented.     

多传感器数据关联优化探讨

对多传感器数据融合是近年来一个热门学科之一,特别在导航、自动控制及机器人技术中得到了广泛应用;对多目标运动进行分析,利用多个或多种传感器提供的冗余信息和互补信息,采用概率关联方法,结合似然函数,通过关联一批数据处理估计目标的运动参数,从而推出快速分布式多传感器空间数据关联算法,这样不但减少观测信息的不确定性和模糊性,同时还提高对目标的检测、跟踪定位和识别能力,增强系统的可靠性和生存能力。     

基于PLSA的面向用户的网络搜索

针对当前的搜索引擎提供面向查询、而非面向用户的服务,从而导致搜索引擎无法满足用户个性化的需求这一问题,提出了一种基于PLSA的新方法,将面向查询词的搜索转变成面向用户的搜索.首先,通过分析用户查询历史和浏览记录建立代表用户模型的用户兴趣向量,在用户发出查询时用户的查询词根据用户兴趣向量被映射到兴趣分类上,最终根据面向用户排序算法将返回结果列表重新排序.实验表明该面向用户搜索系统能够充分考虑用户的偏好,从而更好地满足不同用户的信息需求.     

存在破产风险条件下的最优资本结构研究

破产风险直接关系到企业的存续问题，进而影响到股东财富的最在化，因此，研究存在破产风险条件下的最优资本结构问题具有重要的意义。本文运用贝叶斯概率法来权衡破产风险，并提出股东财富最大化下的最优资本结构模型，以利于我国上市公司在破产机制建立并完善后的资本结构优化决策。     

和积网络的性质分析及其有效性验证算法

和积网络（sum-product networks,SPN）是一种在多层网络中进行快速推理的深度概率图模型,在人工智能领域有广泛应用前景。SPN的有效性即它可用来正确表示概率分布,使得SPN可以表示一些图模型的配分函数和所有的边缘分布。由于只有部分SPN是有效的,快速判断SPN的有效性很有必要。针对SPN理论体系中的有效性验证问题,讨论并揭示SPN内部结构性质,提出验证SPN有效性的两个算法,并给出算法的正确性证明及其复杂度。还通过给出一种新的SPN中生成树个数的计算方法来验证SPN有效性算法的可靠性。     

一种基于隐式信任感知的MOOCs推荐方法

[目的/意义]随着MOOCs迅猛发展和普及,如何利用智能推荐技术为学习者从海量的MOOC中"寻找最佳课程"成为MOOC发展中需要解决的重要课题。[方法/过程]基于自我知觉理论和学习行为投入框架,充分利用学习行为日志和评分数据挖掘学习者之间的隐式信任关系,并通过信任传播建立MOOC社区信任网络,从而构建动态结合兴趣和隐式信任感知的混合推荐方法。为解决数据稀疏问题,提出基于信任的联合概率矩阵分解模型(TA-PMF),将课程评分矩阵、信任关系矩阵的分解相结合来挖掘用户及课程潜在特征,进而实现评分预测。[结果/结论]真实数据集测试结果表明,与显性评分值相比,学习行为投入信息对信任度构建贡献权重达到0.7;TA-PMF方法对MOOC推荐具有较好的适用性,且能在一定程度上缓解冷启动问题。     

漫谈21世纪中国文学的发展趋势

本文认为,当人类即将跨入２１世纪的时候,应该对未来有所预设与规划。中国文学 在２１世纪将以何种姿态出现,发展趋势如何,本文大胆作了预设,并认为,２１世纪中国文学的发展 趋势是以现代化作为总的努力方向,民族性与世界性有机统一,人性因素的进一步展示,表现形式 更加丰富多彩。     

Information Retrieval can Cope with Many Errors

The retrieval of documents that originate from digitized and OCR-converted paper documents is an important task for modern retrieval systems. The problems that OCR errors cause for the retrieval process have been subject to research for several years now. We approach the problem from a theoretical point of view and model OCR conversion as a random experiment. Our theoretical results, which are supported by experiments, show clearly that information retrieval can cope even with many errors. It is, however, important that the documents are not too short and that recognition errors are distributed appropriately among words and documents. These results disclose that an expensive manual or automatic post-processing of OCR-converted documents usually does not make sense, but that scanning and OCR must be performed in an appropriate way and with care.