Verifiable Distributed Oblivious Transfer and Mobile Agent Security

The mobile agent is a fundamental building block of the mobile computing paradigm. In mobile agent security, oblivious transfer (OT) from a trusted party can be used to protect the agent’s privacy and the hosts’ privacy. In this paper, we introduce a new cryptographic primitive called Verifiable Distributed Oblivious Transfer (VDOT), which allows us to replace a single trusted party with a group of threshold trusted servers. The design of VDOT uses a novel technique called consistency verification of encrypted secret shares. VDOT protects the privacy of both the sender and the receiver against malicious attacks of the servers. We also show the design of a system to apply VDOT to protect the privacy of mobile agents. Our design partitions an agent into the general portion and the security-sensitive portion. We also implement the key components of our system. As far as we know, this is the first effort to implement a system that protects the privacy of mobile agents. Our preliminary evaluation shows that protecting mobile agents not only is possible, but also can be implemented efficiently. This work was supported in part by the DoD University Research Initiative (URI) program administered by the Office of Naval Research under grant N00014-01-1-0795. Sheng Zhong was supported by ONR grant N00014-01-1-0795 and NSF grants ANI-0207399 and CCR-TC-0208972. Yang Richard Yang was supported in part by NSF grant ANI-0207399. A preliminary version of this paper was presented at the DialM-POMC Joint Workshop on Foundations of Mobile Computing in 2003. Sheng Zhong received his Ph.D. in computer science from Yale University in the year of 2004. He holds an assistant professor position at SUNY Buffalo and is currently on leave for postdoctoral research at the Center for Discrete Mathematics and Theoretical Computer Science (DIMACS). His research interests, on the practical side, are security and incentives in data mining, databases, and wireless networks. On the theoretical side, he is interested in cryptography and game theory. Yang Richard Yang is an Assistant Professor of Computer Science at Yale University. His research interests include computer networks, mobile computing, wireless networking, sensor networks, and network security. He leads the LAboratory of Networked Systems (LANS) at Yale. His recent awards include a Schlumberger Fellowship and a CAREER Award from the National Science Foundation. He received his B.E. degree from Tsinghua University (1993), and his M.S. and Ph.D. degrees from the University of Texas at Austin (1998 and 2001).     

基于GPS的高层建筑环境激励动态特性研究及应用

本文结合重庆大学主教学楼工程实例,对GPS技术在环境激励下的动态特性进行监控的情况进行了分析和论述。研究结果表明,在高层建筑施工中,应用GPS技术进行建筑物环境激励动态特性监控是一种行之有效的方法。     

码分多址（CDMA）技术和公用空中接口综述

本文主要讨论数字移动通信中扩频码分多址技术，阐明了ＣＤＭＡ体制的优越之外，分析了ＣＤＭＡ的关键技术，全面介绍了ＣＤＭＡ系统设计的基本原则和ＩＳ－９５－Ａ空中接口标准的含义。     

“勇士号”遥控移动式作业机器人

介绍了８６３智能机器人型号之一－以核工业为应用背景的“勇士号”遥控移动式机器人的作业内容及其主要功能指标，分析了该型号的总体设计思想，同时概括总结了其操作性能，移动性能及计算机系统等方面的技术特点。     

气控盘式辅助刹车在车载钻机中的应用分析

在对比分析了传统辅助水刹车与气控盘式辅助刹车的特性后,重点对气控盘式辅助刹车进行了数学分析,得到了该辅助刹车的制动扭矩取决于施加的气体压力,与钻具质量无关,冷却液的流量应同钻柱质量保持正比关系,可精确控制下钻速度并易于实现自动送钻功能。得出了气控盘式辅助刹车更适用于车载钻机的结论。     

Planetary exploration by robotic aerovehicles

Planetary aerobots are a new type of telerobotic science platform that can fly and navigate in a dynamic 3-dimensional atmospheric environment, thus enabling the global in situ exploration of planetary atmospheres and surfaces. Aerobots are enabled by a new concept in planetary balloon altitude control, developed at JPL, which employs reversible-fluid changes to permit repeated excursions in altitude. The essential physics and thermodynamics ofreversible-fluid altitude control have been demonstrated in a series of altitude-control experiments conducted in the Earth's atmosphere, which are described. Aerobot altitude-control technology will be important in the exploration of seven planets and satellites in our solar system. Three of these objects—Venus, Mars, and the Saturnian satellite Titan—have accessible solid surfaces and atmospheres dominated by the dense gases nitrogen or carbon dioxide. They will be explored with aerobots using helium or hydrogen as their primary means of buoyancy. The other four planets—Jupiter, Saturn, Uranus, and Neptune—have deep atmospheres that are predominantly hydrogen. It may be possible to explore these atmospheres with aerobots inflated with atmospheric gas that is then radiatively heated from the hotter gaseous depths below. To fulfill their potential, aerobots to explore the planets will need autonomous state estimators to guide their observations and provide information to the altitude-control systems. The techniques of acquiring these data remotely are outlined. Aerobots will also use on board altitude control and navigation systems to execute complex flight paths including descent to the surface and exploiting differential wind velocities to access different latitude belts. Approaches to control of these systems are examined. The application of aerobots to Venus exploration is explored in some detail: The most ambitious mission described, the Venus Flyer Robot (VFR), would have the capability to make repeated short excursions to the high-temperature surface environment of Venus to acquire data and then return to the Earth-like upper atmosphere to communicate and recool its electronic systems. Finally a Planetary Aerobot Testbed is discussed which will conduct Earth atmospheric flights to validate autonomous-state-estimator techniques and flight-path-control techniques needed for future planetary missions.     

A Macro Model of Frequently Changing Mobile Networks to Perform Flow and Access Control

The area covered by a mobile ad hoc network consists of obstacles that inhibit transmission and areas where communications can take place. Physical structures, such as buildings, that block transmission, or lakes, where forwarding nodes cannot be located, are permanent obstacles. Temporary obstacles are created as mobile nodes enter or leave an area. Our hypothesis is that the spaces between nearby obstacles are bottlenecks that inhibit the flows in the network. We partition the network into areas that are encompassed by obstacles and bottlenecks. All of the nodes in an area are treated as a single super node, and the bottlenecks between areas are the links between the super nodes. As individual nodes move, the flows and paths in the model change more slowly than the paths and flows between the individual nodes. We apply flow control algorithms to the model and perform admission control within a super node based on the flows that are assigned by the flow control algorithm. We apply the model to the Columbia University campus, and use max–min, fair bottleneck flow control to assign the flows. Our hypothesis is verified for this example.     

基于嵌入式移动浏览器的QtWebkit 2.1内核研究与开发

通过对多种支持HTML5技术内核的分析,选取了Webkit内核Qtwebkit2.1。在对其进行深入分析的基础上,着重研究了它对HTML5的支持。最后选取并裁剪了基于Qtwebkit2.1内核的浏览器QtWeb,实现对MeeGo平台的移植。经实验表明,该嵌入式移动浏览器能部分支持HTML5技术规范,为以后的进一步研究奠定了良好的基础。     

基于移动锚节点的无线传感器网络圆心定位

文章提出了一种利用无线传感器网络无线信号接收强度（RSSI）和移动锚节点轨迹来获得待定节点位置的算法。该算法在有多个可移动锚节点的情况下,定位将会更加高效。在定位阶段,通过RSSI测得锚节点到待定节点的距离,并利用三个以上移动锚节点的坐标（包括三个）来求解圆的方程,计算出待定节点的位置。