具有未知参数的机器人-摄像机系统的自适应动态反馈跟踪控制

研究了不确定非完整移动机器人系统的跟踪问题.首先,基于视觉反馈和状态输入变换,展示了一种非完整移动机器人运动学系统的不确定链式模型.基于反步法思想和跟踪误差系统结构,给出了两个重要的新变换.然后运用李雅普诺夫直接方法和扩展巴巴拉引理设计了自适应控制律和动态反馈鲁棒控制器,以实现理想轨迹的跟踪控制.严格证明了闭环误差系统的渐近收敛性.最后,仿真结果证实了提出的控制策略有效.     

定位GSM用户的一种方法

利用GSM协议的一个缺陷,提出一个对GSM用户定位的方法.当用户使用GSM移动电话时,攻击者修改GSM移动电话和基站之间在空中接口传输的一些信令报文子域,诱使GSM移动电话向基站明文传输IMSI和IMEI身份标识符.这种攻击方法能让通信双方对攻击没有察觉,从而保证攻击的隐蔽性.攻击者根据截获的IMSI和IMEI,以及用户所属区域的LAI即可实现对用户的定位.     

新型智能远程控制系统的设计与研究

远程控制软件可以大大简化我们的网络管理工作,更加有效地保证网络和计算机操作系统的安全.本文采用服务器/客户机模式,以Java语言网络编程技术实现了远程控制系统.详细说明体系结构中各模块的主要功能;以流程图的方式详细说明系统软件的实现重点和过程.最后通过Java Socket网络编程,最终实现了新型智能远程担制系统的设计与开发.     

2D游戏的颜色碰撞

文章介绍了2D游戏中一种精确实用的碰撞方法--颜色碰撞.一般在游戏中要碰撞的物体不是矩形而是一些不规则的形状,像弯曲的山路和室内一些不规则设备,如果在这种情况下用正规的区域碰撞检测会有很多问题,而解决的方法就是颜色碰撞.颜色碰撞的原理是取角色的图片像素和当前想碰撞场景的蒙板中的像素进行"或"运算.如果结果全0表示发生碰撞,否则表示正常.     

短信理财平台系统设计与实现方案

电子业务是银行中间业务的一个重要组成部分,直接关系到银行的信誉.本文根据银行业务部的短信理财系统的需求,结合现在移动梦网业务的发展,开发了短信理财系统,实现了短信理财的目标,并就系统的分析、设计和实现进行了详细的阐述.     

A verifiable privacy-preserving data collection scheme supporting multi-party computation in fog-based smart grid

Incorporation of fog computing with low latency,preprocession(e.g.,data aggregation)and location awareness,can facilitate fine-grained collection of smart metering data in smart grid and promotes the sustainability and efficiency of the grid.Recently,much attention has been paid to the research on smart grid,especially in protecting privacy and data aggregation.However,most previous works do not focus on privacy-preserving data aggregation and function computation query on enormous data simultaneously in smart grid based on fog computation.In this paper,we construct a novel verifiable privacy-preserving data collection scheme supporting multi-party computation(MPC),named VPDC-MPC,to achieve both functions simultaneously in smart grid based on fog computing.VPDC-MPC realizes verifiable secret sharing of users’data and data aggregation without revealing individual reports via practical cryptosystem and verifiable secret sharing scheme.Besides,we propose an efficient algorithm for batch verification of share consistency and detection of error reports if the external adversaries modify the SMs’report.Furthermore,VPDC-MPC allows both the control center and users with limited resources to obtain arbitrary arithmetic analysis(not only data aggregation)via secure multi-party computation between cloud servers in smart grid.Besides,VPDC-MPC tolerates fault of cloud servers and resists collusion.We also present security analysis and performance evaluation of our scheme,which indicates that even with tradeoff on computation and communication overhead,VPDC-MPC is practical with above features.     

Computer comparisons in the presence of performance variation

Performance variability,stemming from nondeterministic hardware and software behaviors or deterministic behaviors such as measurement bias,is a well-known phenomenon of computer systems which increases the difficulty of comparing computer performance metrics and is slated to become even more of a concern as interest in Big Data analytic increases.Conventional methods use various measures(such as geometric mean)to quantify the performance of different benchmarks to compare computers without considering this variability which may lead to wrong conclusions.In this paper,we propose three resampling methods for performance evaluation and comparison:a randomization test for a general performance comparison between two computers,bootstrapping confidence estimation,and an empirical distribution and five-number-summary for performance evaluation.The results show that for both PARSEC and highvariance BigDataBench benchmarks 1)the randomization test substantially improves our chance to identify the difference between performance comparisons when the difference is not large;2)bootstrapping confidence estimation provides an accurate confidence interval for the performance comparison measure(e.g.,ratio of geometric means);and 3)when the difference is very small,a single test is often not enough to reveal the nature of the computer performance due to the variability of computer systems.We further propose using empirical distribution to evaluate computer performance and a five-number-summary to summarize computer performance.We use published SPEC 2006 results to investigate the sources of performance variation by predicting performance and relative variation for 8,236 machines.We achieve a correlation of predicted performances of 0.992 and a correlation of predicted and measured relative variation of 0.5.Finally,we propose the utilization of a novel biplotting technique to visualize the effectiveness of benchmarks and cluster machines by behavior.We illustrate the results and conclusion through detailed Monte Carlo simulation studies and real examples.     

从冲动到理性——浓缩中国网商成长史

2008年3月17日,浙江省永康市威仕达五金制造厂总经理杜美燕像往常一样打开电脑,开始查阅来自中国制造网(www.Made-in-China.com)的询盘.这个早在8年前就养成的习惯,为威仕达赢得了外贸销售额中90%的订单.不过最近几天,由于广交会的临近,询盘相对少了些,这让杜美燕忙里偷闲回忆起了往事:尽管公司从2000年的白手起家,到2007年通过电子商务拿到的订单已经超过了300万美元,但是回想这些年来网络外贸的经历,最令杜美燕难忘的还是2003年.     

研究与应用并重创造共赢局面

2006年4月19日～24日,世冠工程(北京)有限公司分别在成都、西安和北京三地进行巡回技术交流.4月24日,世冠公司在北京渔阳饭店举行了"2006年世冠AMEsim航空航天技术研讨会"最后一站的北京专场,会议邀请IMAGINE公司航空航天事业部总监Joel Tollefson先生、法国图卢兹国家科学与应用研究院机械工程系主任Mare教授发表了系列演讲,在会议现场,精彩的演讲引发了与会人员的浓厚兴趣.笔者也借此机会,就感兴趣的问题采访了Joel Tollefson先生、Mare教授以及世冠公司总经理李京燕女士.     

Altair铁三角:驱动产品创新设计

在美国IT业的发展史上,蕴含着数不清的传奇.Bill和Paul辍学建立微软帝国,乔布斯和沃兹在车库里创造苹果神话……这些都是广为人知的.而在更为专业、高端的CAE领域,似乎没人会相信这样的神话.因为,创建一家专业的CAE公司显然更为复杂,需要更多的资金和工程技术积累,几乎所有的CAE公司都是在政府、科研机构和商业公司的合力推动下才得以诞生和发展.