农产品运输距离与变质关系的数学建模分析

针对农产品运输过程的变质问题,考虑运输距离和变质损失的干扰,通过农产品的指数变质函数描述农产品的鲜活度随时间和温度的变化情况,依据农产品变质特征、运输距离的限制、运输成本、客户时间窗约束和农产品变质函数等约束规范下,塑造农产品的运输距离同变质关系的动态联合优化模型,采用最大最小蚂蚁算法,求解静态农产品变质条件下联合优化模型,获取最佳农产品运输距离,通过动态规划算法,求解动态农产品变质条件下联合优化模型,获取最佳农产品运输距离。采用MAT-LAB7的最优化求解功能能够获取模型的最佳解。实验结果说明,所提模型能够在确保农产品质量的条件下,有效获取最佳农产品运输距离。     

铁路煤炭运输网络流量分配优化模型研究

文章依托于抽象的铁路运输网络,对铁路煤炭运输网络的结构、布局和特性进行分析,并选取适当的重要节点进行计算,选取合适的优化目标和流量分配方法,使之研究模型最终可应用于实际的铁路煤炭运输网络之中,解决运输流量分配问题。     

大型民航通信系统鲁棒性测试模型仿真分析

民航通信系统属于复杂网络通信系统,系统的通信节点数目庞大,传统的复杂网络鲁棒性分析算法性测试结果存在失真。为此提出一种分层权重划分理论的鲁棒性分析模型,并应用到航空通信系统的鲁棒性检测中,塑造BP神经网络大型民航通信系统鲁棒性评价模型,对影响大型民航通信系统鲁棒性的各项指标进行打分,依据综合得分进行不同的加权,获取大型民航通信系统鲁棒性评价指标的分层权重样本测试数据,按照获取的大型民航通信系统信息以及信息的改变量,对自适应加权BP神经网络权向量进行修正,建立大型民航通信系统中不同节点间的关联约束关系,将某种约束条件引入传统的关联规则中,提高大型民航通信系统鲁棒性测试的效率,获取准确的测试结果。实验结果表明,采用所提模型能更精确的分析出航空通信设备的鲁棒性。     

大数据环境下基于信息融合的网络风险评估模型

大数据环境下网络风险评估具有多数据源的特点,导致传统的基于神经网络的网络风险评估模型,由于未对多元数据分类而无法实现网络风险评估,提出一种基于信息融合的大数据环境下网络风险评估模型,将检测结果汇总后获取综合攻击发生概率,选用优化的D-S证据理论方法对相关检测设备的mass函数值进行合成并完成数据源的融合,然后求出攻击发生支持概率,依据态势要素融合求出每个主机节点的网络风险态势,通过态势要素融合求出主机节点的网络风险态势,再根据每个主机节点的安全态势得出每个节点权重的融合,获取网络风险态势值,利用数据源融合、态势要素融合以及节点态势融合获取网络风险态势值,在此基础上分析网络风险评估模型。仿真实验结果表明所提方法具有很高的精度。     

携带传感节点高速运动下的运动参数精确测试

传统依据卡曼尔滤波器的运动参数测试算法,受到人体高速运动目标信号模糊以及光电传感器畸变的干扰,测试的结果存在较大的误差问题,存在较大的弊端。提出一种应用光电传感器和优化卡曼尔滤波算法的携带传感节点高速运动参数测量方法,分析了光电传感器检测信号的原理,采用高精密光反射型传感器对携带传感节点运动目标信号进行探测,利用光电传感器探测反射光信号,将携带传感节点运动信号转换为电信号,通过信号调理将电路放大后,采用微控制器完成运动目标信号的采集,通过优化的卡尔曼算法,获取一套递推预测算法,以信号和噪声的状态空间模型为依据,基于前一时刻的预测值和当前时刻的预测值,调整携带传感节点高速运动下人体运动参数变量的预测值,动态调整检测噪声的协方差,对携带传感节点高速运动参数进行准确预测。实验检测结果表明,所提方法可对含传感节点的运动参数进行高效检测,该种算法精度高,可有效的降低高速运动目标的信号模糊和光电传感器畸变等因素产生的误差问题。     

正交通信信道载波均衡故障节点准确挖掘算法

大型云计算联合服务器中故障节点的快速挖掘模型构建可以实现对云服务器故障的准确定位和检测。传统方法中采用协议堆栈对节点进行约束与管理,达到故障节点快速挖掘的目的,然而该算法在Sink节点位置部署考虑欠好,在通信传输中很容易相邻节点信道间频谱主瓣重叠,故障节点挖掘性能不好。针对这一问题,提出一种基于正交通信信道载波均衡的云计算联合服务器故障节点快速挖掘算法,建立故障节点信息融合模型,进行特征分析,在信息融合过程中,组成新的云计算联合服务器接收端和发射端故障节点定位训练序列,构建基于OFDM系统的等效基带故障节点挖掘模型,通过正交通信信道载波均衡实现云服务器故障节点的快速挖掘。仿真结果表明,该算法在复杂云计算环境下,能实现对故障节点的准确定位,挖掘性能较高,检测概率较高,优越于传统模型。     

邮路规划问题研究——以彭泽县为例

邮政运输网络是邮政企业运营的重要保障,是决定邮政企业竞争能力的主要因素.时限与成本是邮政运输问题的两个重要指标.本文首先介绍了一些求路径最短的方法,然后根据彭泽县邮政局分布情况,在满足邮政运输流程及时限规定的前提下,设计出邮路规划与邮车调度方案.其具体方法为先利用floyd算法计算出任意2个邮局之间的最短距离和路径;再用二边逐次修正法生成最佳哈密尔顿圈;最后利用最小生成树设计出最佳路径.     

时变条件下的危险品运输与应急救援双层规划研究

危险品运输因其发生事故的后果危害性大,因此对于如何选择一条既能保证运输安全又能满足运输需求的最优路径已经成为一项非常重要的研究内容。在总结前人研究的基础上,提出在时变条件下考虑应急救援的危险品运输路径双层规划模型,同时考虑运输时间限制与出发等待时间弹性以及运输网络中的应急救援能力。通过算法求解与应用算例,结果表明:双层规划更好地描述了企业和政府之间的博弈决策,而且将应急救援因素作为路径选择的重要依据有利于寻求更符合实际的最优路径。     

非密集分布下传感网络节点选择优化算法研究

提出一种混沌差分进化和动态逃逸粒子群的节点选择优化算法,通过混沌序列的均匀遍历特性和差分进化算法的高效全局搜索能力,对传感网络中的节点能量进行分类搜索,采用Logistics混沌映射对节点进行优化分区处理,将混沌扰动量融入节点能量分区过程中,获取最佳能量节点,利用动态逃逸粒子群方法,运算无线传感网络最佳能量节点的最优位置,实现网络节点覆盖优化。仿真结果说明,所提算法可增强无线传感网络最优节点的聚类性能,具有更好的无线传感器网络动态节点选择性能,并且收敛速度快,运算耗时少。     

基于大型混合网络的突变流量控制模型仿真分析

当大型混合网络受到异常攻击或大规模登录时,流量会发生短时间的巨幅变化,使得单个节点面临瘫痪的风险,导致传统基于单个节点的大型混合网络突变流量控制模型,由于不能适应流量大幅度变化,无法有效实现突变流量控制。提出一种基于自适应PD流量控制算法的大型混合网络突变流量控制模型,将大型混合网络流量统计时间划分成几个周期,获取周期个数的估计值,求出大型混合网络操作行为数据序列中的各统计周期中数据的离均差平方、与组间离均差平方和以及各周期中的方差比值,对流量成分模型进行塑造,通过简单PD控制算法对突变流量进行初步控制,引入延时环节,获取各闭环极点的位置,求出PD控制器参数求出交换节点瓶颈链接个数的估测值,从而实现突变流量控制。仿真实验结果表明,所提方法在控制突变流量方面具有很高的优越性及高效性。     

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.     

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     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.