大渡河安宁水电站深厚覆盖层勘探技术 与方法概述

本文介绍了大渡河上游安宁水电站可研阶段河床深厚覆盖层勘探所用的技术与方法，即：植物胶钻具钻进、厚壁套管跟管钻进及多级跟管钻头钻进。此外，还介绍了覆盖层钻孔孔内旁压试验和原状砂样的采取技术。在该深厚覆盖层勘探中应用的技术与方法保证了勘探工作的圆满完成，为工程设计提供了详实、可靠、全面的参数，同时也完善勘探技术与内容，提高了勘探水平，为今后的勘探工作作了相应的技术储备。     

一种基于视向的LOD自动生成方法

总结了LOD自动生成的一般算法,结合DEM均匀网格模型,以“块”作为地形模型简化的空间单位。结合实际视觉效果中观察点位置和角度对场景细节程度的影响,以一个包含视点视向相关因子的尺度作为简化标准。简化过程中采取稀疏采样的策略,建立了多层次LOD数据模型,有效地简化了地形模型的绘制,提高了生成效率,使得生成的三维地形有较高的可视性和真实感。     

椭圆曲线上的多级代理签名方案

在已知的各种代理签名方案中,原始签名人和代理签名人只能进行一级代理。但在有些情形下,签名权利需要逐级向下代理,而已知的方案不能满足这种需要。本文基于椭圆曲线提出了一种多级代理签名方案。在该方案中,原始签名人不仅可授权1级代理签名人对消息进行签名,而且1级代理签名人可在许可范围内继续逐级授权。新方案具有实现简单且安全性高等特点,而且也是迄今为止第一类多级代理签名方案。另外,该文还在上述方案的基础上,提出了多级多代理多签名方案。它的适用范围更加广泛,已知的一些代理签名方案可看作它的特例。同时,它也满足有效性、不可否认性、安全性等性质。     

数据流查询处理中一种共享的分级窗口维护策略

由于数据流具有无界的特性,数据流系统中的查询多为带有窗口的查询,对带有窗口的查询,现有方法常由操作符直接维护窗口,但操作符的类型及排列方式可能会导致窗口难以维护,且冗余度较大.因此提出一种查询处理中的分级窗口维护策略,将窗口分为流窗口和操作符窗口,以流窗口为主并控制操作符窗口的维护,使查询中的窗口保持一致,解决了窗口维护问题,并且符合流查询语言的语义,各级窗口中的数据通过共享来解决内存消耗问题.     

一种基于多层次特征的目标继承提取方法

图像的有效分割或提取是图像处理与分析的重要内容，本文使用一种基于多层次特征的方法，针对噪声大，干扰多，光照不均，场景多变，目标形状多变这类图像，自原图像开始，得到各层次的特征，继承地利用低高层次特征逐步提取目标，而又可以回溯前面的原图像或低层次特征信息，继承地对所提取目标优化，实际目标与背景分离．实验表明，该算法可以正确高效地提取目标，有较高的鲁奉性和精度，对具有不同目标大小和信噪比的图像也能得到较好的提取效果．     

Design and Analysis of Optimal Multi-Level Hierarchical Mobile IPv6 Networks

Hierarchical Mobile IPv6 (HMIPv6) is an enhanced version of Mobile IPv6 designed to reduce signaling overhead and to support seamless handoff in IP-based wireless/mobile networks. To support more scalable services, HMIPv6 networks can be organized as the form of a multi-level hierarchy architecture (i.e., tree structure). However, since multi-level HMIPv6 networks incur additional packet processing overhead at multiple mobility agents, it is important to find the optimal hierarchy level to minimize the total cost, which consists of the location update cost and the packet delivery cost. In this paper, we investigate this problem, namely the design of an optimal multi-level HMIPv6 (OM-HMIPv6) network. To accomplish this, we design a function to represent the location update cost and the packet delivery cost in multi-level HMIPv6 networks. Based on these formulated cost functions, we calculate the optimal hierarchy level in multi-level HMIPv6 networks, in order to minimize the total cost. In addition, we investigate the effects of the session-to-mobility ratio (SMR) on the total cost and the optimal hierarchy. The numerical results, which show various relationships among the network size, optimal hierarchy, and SMR, can be utilized to design an optimal HMIPv6 network. In addition, the analytical results are validated by comprehensive simulations. Sangheon Pack received his B.S. (2000, magna cum laude) and Ph.D. (2005) degrees from Seoul National University, both in computer engineering. He is a post doctor fellow in the School of Computer Science and Engineering at the Seoul National University, Korea. He is a member of the IEEE and ACM. During 2002–2005, he was a recipient of the Korea Foundation for Advanced Studies (KFAS) Computer Science and Information Technology Scholarship. He has been also a member of Samsung Frontier Membership (SFM) from 1999. He received a student travel grant award for the IFIP Personal Wireless Conference (PWC) 2003. He was a visiting researcher to Fraunhofer FOKUS, German in 2003. His research interests include mobility management, wireless multimedia transmission, and QoS provision issues in the next-generation wireless/mobile networks. Yanghee Choi received B.S. in electronics engineering from Seoul National University, M.S. in electrical engineering from Korea advanced Institute of Science, and Doctor of Engineering in Computer Science from Ecole Nationale Superieure des Telecommunications (ENST) in Paris, in 1975, 1977 and 1984 respectively. Before joining the School of Computer Engineering, Seoul National University in 1991, he has been with Electronics and Telecommunications Research Institute (ETRI) during 1977–1991, where he served as director of Data Communication Section, and Protocol Engineering Center. He was research student at Centre National d'Etude des Telecommunications (CNET), Issy-les-Moulineaux, during 1981–1984. He was also Visiting Scientist to IBM T.J. Watson Research Center for the year 1988–1989. He is now leading the Multimedia Communications Laboratory in Seoul National University. He is also director of Computer Network Research Center in Institute of Computer Technology (ICT). He was editor-in-chief of Korea Information Science Society journals. He was chairman of the Special Interest Group on Information Networking. He has been associate dean of research affairs at Seoul National University. He was president of Open Systems and Internet Association of Korea. His research interest lies in the field of multimedia systems and high-speed networking. Minji Nam received her B.S. and M.S degrees in Computer Science and Engineering from Seoul National University in 2003 and 2005, respectively. From 2005, she has worked on Portable Internet Development Team for Korea Telecom. Her research interests are mobile networks, portable internet technology (IEEE 802.16) and Mobile IPv6.     

The Cell Broadband Engine: Exploiting Multiple Levels of Parallelism in a Chip Multiprocessor

As CMOS feature sizes continue to shrink and traditional microarchitectural methods for delivering high performance (e.g., deep pipelining) become too expensive and power-hungry, chip multiprocessors (CMPs) become an exciting new direction by which system designers can deliver increased performance. Exploiting parallelism in such designs is the key to high performance, and we find that parallelism must be exploited at multiple levels of the system: the thread-level parallelism that has become popular in many designs fails to exploit all the levels of available parallelism in many workloads for CMP systems. We describe the Cell Broadband Engine and the multiple levels at which its architecture exploits parallelism: data-level, instruction-level, thread-level, memory-level, and compute-transfer parallelism. By taking advantage of opportunities at all levels of the system, this CMP revolutionizes parallel architectures to deliver previously unattained levels of single chip performance. We describe how the heterogeneous cores allow to achieve this performance by parallelizing and offloading computation intensive application code onto the Synergistic Processor Element (SPE) cores using a heterogeneous thread model with SPEs. We also give an example of scheduling code to be memory latency tolerant using software pipelining techniques in the SPE. This paper is based in part on “Chip multiprocessing and the Cell Broadband Engine”, ACM Computing Frontiers 2006.     

基于量子神经网络的手写体数字识别方法研究

手写体数字识别问题是模式识别领域的一个重要研究课题.提出了一种基于多层激励函数的量子神经网络和多级分类器组合的手写体数字识别方法,采用MNIST数据库进行训练和测试.实验结果表明,该识别方法在识别率和可靠性方面均有很好的效果,同时也体现出量子神经网络用于模式识别的优越性和潜力.     

面向多级逻辑的低功耗有限状态机状态分配

状态分配在低功耗有限状态机设计中已经被证明是很有效的方法.该文针对有限状态机多级组合逻辑实现提出了一个新的成本函数,并利用整体退火遗传算法来进行状态码的搜索,通过减少电路的开关活动性和组合逻辑部分的面积来达到功耗的降低.对25个有限状态机标准测试电路进行面积和功耗的测试表明:与已发表的针对面积和功耗优化的算法相比,该文所提出的算法不但在功耗降低上具有较大的改进,在面积改善上也具有一定的优势.     

双线性系统多目标控制问题研究

研究了双线性系统的多目标控制问题. 首先把多目标控制问题, 通过效用函数技术转化为一个单目标最优控制问题, 其中, 效用函数是多个二次型性能指标的非线性函数, 因此, 在动态规划的意义下是不可分的. 然后, 为了克服不可分对求解带来的困难, 提出了一种两级最优控制算法. 下级用动态规划求解一个参数化的具有双线性---二次型结构的辅助 Lagrangian 问题；上级迭代调整辅助 Lagrangian 问题中的参数向量. 不断重复这个过程, 直至最优性条件被满足.