基于复合神经网络的致密储层测井评价方法研究

本文利用集成的思想开展了复合神经网络模型研究。首先,利用MATLAB软件平台构建了反向传播神经网络(BP)、支持向量神经网络(SVM)和径向基函数神经网络(RBF)三个单一神经网络。其次,将单一的神经网络以加权平均的规则进行组装,形成一种复合的神经网络系统。最后,利用复合神经网络系统开展了测井储层孔隙度、渗透率和含水饱和度的预测及效果分析。研究结果显示,相比于单一的神经网络方法,构建的复合神经网络模型预测的储层孔隙度、渗透率和含水饱和度精度更高,表明基于复合神经网络模型进行储层评价是可行和有效的。     

基于Elman神经网络的电信业务预测研究

介绍了Elman神经网络的结构,并将Elman神经网络应用于我国电信业务量预测。仿真结果和BP神经网络对比表明,Elman神经网络的预测结果更精确。     

三种常用的人工神经网络

人工神经网络是一种由大量简单的处理单元组成的非线性、自适应、自组织系统。本文介绍了神经网络的基本要素、网络拓扑结构特性及不同网络拓扑结构下的工作特性,并综述了BP神经网络、RBF神经网络、Hopfield神经网络这三种应用比较广泛的神经网络的网络拓扑结构及算法。     

基于改进的神经网络异常声音自动识别系统研究

针对标准的BP神经网络对于声音信号识别率不高的问题,提出了一种用粒子群算法（PSO）优化BP神经网络的算法,建立了声音信号识别模型。PSO优化BP神经网络主要是用PSO来优化BP神经网络的初始权值和闽值,然后通过训练BP神经网络得到识别模型的最优解,优化后的神经网络具有误判率小、反应速度快等特点。在实验中把标准的BP神经网络和PSO优化后的BP神经网络用于八种异常声音的MFCC特征量和差分MFCC特征量识别,结果表明：在声音信号的识别系统中采用PSO优化BP神经网络的算法提高了系统的识别性能,达到了系统设计的目的。     

Hopfield神经网络在噪声字符识别中的应用

本文介绍了Hopfield神经网络相关知识,采用离散Hopfield神经网络对噪声字符进行识别．仿真使用离散Hopfield神经网络识别不同污染率的噪声字符,结果表明离散Hopfield神经网络对噪声字符的识别率高.     

倒立摆系统的模糊神经网络控制

本文采用神经网络与自适应神经网络模糊推理（Anfis）工具对一级倒立摆进行控制。在神经网络控制的基础上,将神经网络控制与模糊控制相结合,利用神经网络学习模糊控制规则数据,对模糊神经控制器进行训练。实验表明,当模型参数改变及干扰作用时,自适应神经网络模糊推理系统有良好的自适应能力,能使倒立摆小车抵抗外界干扰并能较准确地到达预定位置。     

BP神经网络模型与学习算法

分析了神经网络算法的基本原理,给出了BP神经网络算法的具体实现方法,总结了它的特点,并给出了基本流程。采用Matlab软件编程实现BP神经网络算法。将神经网络算法应用于函数逼近问题中,并分析相关参数对算法运行结果的影响,最后对BP神经网络算法进行了展望。     

基于深度神经网络的直线二级倒立摆控制器设计

针对直线二级倒立摆抗干扰控制器设计问题,研究了基于深度神经网络的智能控制方法。首先介绍了BP神经网络和深度神经网络模型及优化算法,并且根据直线二级倒立摆状态方程,研究了基于深度神经网络的直线二级倒立摆控制算法。然后设计了一个六输入单输出的深度神经网络控制器模型,并利用Pytorch框架,以LQR作为导师进行神经网络的训练,训练完成后利用MATLAB软件对训练后的神经网络进行仿真实验验证,并与BP神经网络控制器进行对比,最后在直线二级倒立摆实验平台上进行实验验证。仿真与实验表明,所设计的深度神经网络控制器能够实现直线二级倒立摆的良好抗干扰控制,从而证明了该研究设计方法的合理性和有效性。     

基于BP神经网络的科技人才需求预测

采用BP神经网络模型解决科技人才需求预测问题。首先介绍BP神经网络结构和学习算法,其次确定科技人才需求预测影响因素指标,作为BP神经网络输入,最后以Matlab为运行平台实现BP神经网络模型,并以河南省科技人才为例进行案例分析,应用BP神经网络模型预测河南省2008-2010年科技人才需求量。     

基于小波神经网络的电力负荷预测

小波神经网络是建立在小波理论基础上的一种新型前馈神经网络,具有许多优良特性。本文分析了小波神经网络的特点,建立了电力负荷的小波神经网络预测模型,设计了小波神经网络结构,给出了小波网络参数调节算法。对实际电力负荷预测算例,以及与BP网络的对比研究实验表明,小波神经网络对非平稳信号能进行有效地预测,比BP神经网络具有更高的预测精度。     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese