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101.
The numerical solution of nonlinear equation systems is often achieved by so-called quasi-Newton methods. They preserve the
rapid local convergence of Newton’s method at a significantly reduced cost per step by successively approximating the system
Jacobian though low-rank updates. We analyze two variants of the recently proposed adjoint Broyden update, which for the first
time combines the classical least change property with heredity on affine systems. However, the new update does require, the
evaluation of so-called adjoint vectors, namely products of the transposed Jacobian with certain dual direction vectors. The
resulting quasi-Newton method is linear contravariant in the sense of Deuflhard (Newton methods for nonlinear equations. Springer,
Heidelberg, 2006) and it is shown here to be locally and q-superlinearly convergent. Our numerical results on a range of test problems demonstrate that the new method usually outperforms
Newton’s and Broyden’s method in terms of runtime and iterations count, respectively.
Partially supported by the DFG Research Center Matheon “Mathematics for Key Technologies”, Berlin and the DFG grant WA 1607/2-1. 相似文献
102.
In wireless access, transmitter nodes need to make individual decisions for distributed operation and do not necessarily cooperate
with each other. We consider a single-receiver random access system of non-cooperative transmitters with the individual objectives
of optimizing their throughput rewards, transmission energy costs and delay costs. The non-cooperative transmitter behavior
may be purely selfish or may also reflect malicious objectives of generating interference to prevent the successful transmissions
of the other nodes as a form of denial of service attack. Our goal is to evaluate the interactions between selfish and malicious
nodes that have the dual objectives of optimizing their individual performance measures and blocking the packet transmissions
of the other selfish nodes. We assume saturated packet queues of infinite buffer capacities and consider a general multi-packet
reception channel that allows packet captures in the presence of simultaneous transmissions. In this context, we formulate
a non-cooperative random access game of selecting the individual probabilities of transmitting packets to a common receiver.
We derive the non-cooperative transmission strategies in Nash equilibrium. The analysis provides insights for the optimal
strategies to block random access of selfish nodes as well as the optimal defense mechanisms against the possible denial of
service attacks of malicious nodes in wireless networks. The results are also compared with the cooperative equilibrium strategies
that optimize the total system utility (separately under random access and scheduled access). A pricing scheme is presented
to improve the non-cooperative operation. For distributed implementation, we formulate a repeated game of the best-response
strategy updates and introduce adaptive heuristics (based on the channel feedback only) provided that the system parameters
are not explicitly known at the individual transmitters.
Yalin Evren Sagduyu received his B.S. degree from Bogazici University, Turkey, in 2000 in Electrical and Electronics Engineering, and M.S. and Ph.D. degrees from the University of Maryland at College Park in 2002 and 2007, respectively, in Electrical and Computer Engineering. He has been a graduate research assistant with the Institute for Systems Research at the University of Maryland. He is currently a postdoctoral fellow in the Department of Electrical Engineering and Computer Science at Northwestern University. His research interests are in the areas of design and optimization of wireless ad hoc and sensor networks, game theory applications in communication systems, multi-user information theory and network coding. Anthony Ephremides received his B.S. degree from the National Technical University of Athens (1967), and M.S. (1969) and Ph.D. (1971) degrees from Princeton University, all in Electrical Engineering. He has been at the University of Maryland since 1971, and currently holds a joint appointment as professor in the Electrical Engineering Department and the Institute of Systems Research (ISR). He is co-founder of the NASA Center for Commercial Development of Space on Hybrid and Satellite Communications Networks established in 1991 at Maryland as an offshoot of the ISR. He was a visiting professor in 1978 at the National Technical University of Athens, Greece, and in 1979 at the Electrical Engineering and Computer Science Department of the University of California at Berkeley and INRIA, France. During 1985–1986 he was on leave at Massachusetts Institute of Technology and the Swiss Federal Institute of Technology, Zurich. He has been President of the Information Theory Society of the IEEE (1987), and served on the Board of the IEEE (1989 and 1990). His interests are in the areas of communication theory, communication systems and networks, queuing systems, signal processing, and satellite communications. 相似文献
Anthony EphremidesEmail: |
Yalin Evren Sagduyu received his B.S. degree from Bogazici University, Turkey, in 2000 in Electrical and Electronics Engineering, and M.S. and Ph.D. degrees from the University of Maryland at College Park in 2002 and 2007, respectively, in Electrical and Computer Engineering. He has been a graduate research assistant with the Institute for Systems Research at the University of Maryland. He is currently a postdoctoral fellow in the Department of Electrical Engineering and Computer Science at Northwestern University. His research interests are in the areas of design and optimization of wireless ad hoc and sensor networks, game theory applications in communication systems, multi-user information theory and network coding. Anthony Ephremides received his B.S. degree from the National Technical University of Athens (1967), and M.S. (1969) and Ph.D. (1971) degrees from Princeton University, all in Electrical Engineering. He has been at the University of Maryland since 1971, and currently holds a joint appointment as professor in the Electrical Engineering Department and the Institute of Systems Research (ISR). He is co-founder of the NASA Center for Commercial Development of Space on Hybrid and Satellite Communications Networks established in 1991 at Maryland as an offshoot of the ISR. He was a visiting professor in 1978 at the National Technical University of Athens, Greece, and in 1979 at the Electrical Engineering and Computer Science Department of the University of California at Berkeley and INRIA, France. During 1985–1986 he was on leave at Massachusetts Institute of Technology and the Swiss Federal Institute of Technology, Zurich. He has been President of the Information Theory Society of the IEEE (1987), and served on the Board of the IEEE (1989 and 1990). His interests are in the areas of communication theory, communication systems and networks, queuing systems, signal processing, and satellite communications. 相似文献
103.
随着硬件和通信技术的飞速发展,数据流技术已广泛应用于金融分析、网络监控及传感器网络等诸多领域,这类应用通常具有高速、海量、连续和实时等特性.因此,在数据流上渐进、实时地更新索引成为一个极具价值和挑战性的问题.为了克服现有支持频繁更新的索引树性能大都深受处理器缓存失效率的影响,提出了一种新颖的基于双Memo的量化R*索引树-QDM-Tree(Quantized R*-tree with Double Memos),并给出了相应的插入、删除、更新和范围查询算法,理论分析表明:与已有R*树及其变种相比,该索引树能成倍地压缩树结点,具有更强支持频繁更新的能力. 相似文献
104.
Filter methods were initially designed for nonlinear programming problems by Fletcher and Leyffer. In this paper we propose a secant algorithm with line search filter method for nonlinear equality constrained optimization. The algorithm yields the global convergence under some reasonable conditions. By using the Lagrangian function value in the filter we establish that the proposed algorithm can overcome the Maratos effect without using second order correction step, so that fast local superlinear convergence to second order sufficient local solution is achieved. The primary numerical results are presented to confirm the robustness and efficiency of our approach. 相似文献
105.
BABAIE-KAFAKI Saman 《中国科学 数学(英文版)》2011,(9)
By making a convex combination of the modified secant equations proposed by Yuan and Wei et al.,a hybrid secant equation and also,a modified BFGS algorithm is proposed.The hybridization parameter is effectively computed using the available information of recent iterations.Under proper conditions,it is shown that the proposed algorithm is globally,locally and superlinearly convergent.By using the performance profile introduced by Dolan and Mor'e,a comparison between the implementations of the proposed algori... 相似文献
106.
107.
在视觉跟踪中,传统模型更新算法在遮挡、光照变化及自身旋转等情况下通常存在鲁棒性较差的问题.为改善该性能,提出一种对多表观特征相应子模型进行选择性更新的鲁棒视觉跟踪算法.该算法首先建立候选子模型库,然后通过三个互补特征融合的粒子滤波跟踪确定当前帧目标位置和信息,最后将当前帧三种特征直方图信息与候选库中各子模型分别计算加权相似度,更新候选库后与阈值比较,判断是否更新当前子模型.实验结果表明:本文算法能够对特征相应子模型进行有效的选择性更新,与对比算法比较,在多种复杂变化的跟踪条件下,总体上能够具有更好的跟踪鲁棒性. 相似文献
108.
EPG在数字电视中的应用 总被引:2,自引:0,他引:2
电视传输数字化,多种业务可以混合在一起通过一个信道传输,因此数字电视不再是单一的电视业务,而是通过电视传输通道传输的数字业务,包括视频、音频、图像、数据等,EPG(电子节目指南)系统是数字电视中必不可少的工具。 相似文献
109.
To solve the problem that convergent encryption was commonly used in existing encrypted deduplication systems in cloud storage and data owner couldn’t effectively enforce access control on their outsourced data,an encrypted deduplication system was proposed to support access control functions such as identity authentication,authorization deduplication and the update of access control policy.The outsourced data was only deduplicated with the authorized users,and the unauthorized users couldn’t obtain any data information.CP-ABE and the partition of the ElGamal private key were used to update the access control policy of data.Self-control objects was used to encapsulate user’s data and its access policy,providing authentication for data visitors and ensuring the access control policies enforced effectively.Security analysis and simulation results demonstrate that the proposed system enables data access control and executes efficiently. 相似文献
110.
基于归一化互信息的图像目标跟踪算法,在目标发生刚体旋转,出现遮挡或光照条件发生变化时具有较好的稳定性。但是,实用的跟踪系统还要求算法能实时适应运动目标的外观变化,因此,在对归一化互信息跟踪算法研究的基础上,引入基于多尺度图像信息量的模板尺寸自适应更新策略。实验结果证明,改进的跟踪算法,在目标尺寸变化时能够自适应更新模板... 相似文献