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2006 IEEE International Conference on Communications, ICC 2006

作者： Fazel, Fatemeh Jafarkhani, Hamid Center for Pervasive Communications and Computing Department of Electrical Engineering and Computer Science University of California Irvine United States

ISBN: (纸本)1424403553

In this paper, we propose a novel class of Space-Frequency and Space-Time-Frequency block codes based on Quasi-Orthogonal designs, over a frequency selective Rayleigh fading channel. The proposed codes are able to achieve rate one and full diversity by exploiting the space and multipath diversity gains available in the MIMO-OFDM channel. As the simulation results show, our codes outperform the existing SpaceFrequency block codes in terms of bit error rate performance. Additionally, the proposed Space-Time-Frequency code benefits from a reduced maximum likelihood decoding complexity, which is a huge simplification compared to the existing codes. We also discuss the conditions under which the maximum likelihood decoding for our proposed Quasi-Orthogonal Space-Frequency code is simplified as well.

关键词： Block codes

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Optimal interdiction of urban criminals with the aid of real-time information 33

Optimal interdiction of urban criminals with the aid of real...

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33rd AAAI Conference on Artificial Intelligence, AAAI 2019, 31st Annual Conference on Innovative Applications of Artificial Intelligence, IAAI 2019 and the 9th AAAI Symposium on Educational Advances in Artificial Intelligence, EAAI 2019

作者： Zhang, Youzhi Guo, Qingyu An, Bo Tran-Thanh, Long Jennings, Nicholas R. School of Computer Science and Engineering Nanyang Technological University Singapore Department of Electronics and Computer Science University of Southampton United Kingdom Departments of Computing and Electrical and Electronic Engineering Imperial College United Kingdom

ISBN: (纸本)9781577358091

Most violent crimes happen in urban and suburban cities. With emerging tracking techniques, law enforcement officers can have real-time location information of the escaping criminals and dynamically adjust the security resource allocation to interdict them. Unfortunately, existing work on urban network security games largely ignores such information. This paper addresses this omission. First, we show that ignoring the real-time information can cause an arbitrarily large loss of efficiency. To mitigate this loss, we propose a novel NEtwork purSuiT game (NEST) model that captures the interaction between an escaping adversary and a defender with multiple resources and real-time information available. Second, solving NEST is proven to be NP-hard. Third, after transforming the non-convex program of solving NEST to a linear program, we propose our incremental strategy generation algorithm, including: (i) novel pruning techniques in our best response oracle;and (ii) novel techniques for mapping strategies between subgames and adding multiple best response strategies at one iteration to solve extremely large problems. Finally, extensive experiments show the effectiveness of our approach, which scales up to realistic problem sizes with hundreds of nodes on networks including the real network of Manhattan. © 2019, Association for the Advancement of Artificial Intelligence (***). All rights reserved.

关键词： Crime

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AED: An anytime evolutionary DCOP algorithm 19

AED: An anytime evolutionary DCOP algorithm

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19th International Conference on Autonomous Agents and Multiagent Systems, AAMAS 2020

作者： Mahmud, Saaduddin Choudhury, Moumita Mosaddek Khan, Md. Tran-Thanh, Long Jennings, Nicholas R. Department of Computer Science and Engineering University of Dhaka Bangladesh School of Electronics and Computer Science University of Southampton United Kingdom Departments of Computing and Electrical and Electronic Engineering Imperial College London United Kingdom

ISBN: (纸本)9781450375184

Evolutionary optimization is a generic population-based metaheuristic that can be adapted to solve a wide variety of optimization problems and has proven very effective for combinatorial optimization problems. However, the potential of this metaheuristic has not been utilized in Distributed Constraint Optimization Problems (DCOPs), a well-known class of combinatorial optimization problems prevalent in Multi-Agent Systems. In this paper, we present a novel population-based algorithm, Anytime Evolutionary DCOP (AED), that uses evolutionary optimization to solve DCOPs. In AED, the agents cooperatively construct an initial set of random solutions and gradually improve them through a new mechanism that considers an optimistic approximation of local benefits. Moreover, we present a new anytime update mechanism for AED that identifies the best among a distributed set of candidate solutions and notifies all the agents when a new best is found. In our theoretical analysis, we prove that AED is anytime. Finally, we present empirical results indicating AED outperforms the state-of-the-art DCOP algorithms in terms of solution quality. © 2020 International Foundation for Autonomous.

关键词： Multi agent systems

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A GALS router for asynchronous network-on-chip 14

A GALS router for asynchronous network-on-chip

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2nd ACM International Workshop on Many-Core Embedded Systems, MES 2014, Held in Conjunction with the 41st International Symposium on computer Architecture, ISCA 2014

作者： Yaghini, Pooria M. Eghbal, Ashkan Bagherzadeh, Nader Department of Electrical Engineering and Computer Science Center for Pervasive Communications and Computing University of California Irvine United States

ISBN: (纸本)9781450328227

A scalable asynchronous NoC router with lower power con- sumption and latency comparing to a synchronous design is introduced in this article. It employs GALS interfaces (syn- chronous to asynchronous/asynchronous to synchronous), imposing negligible area overhead to handle the Metasta- bility issue. It is synthesized with the help of Persia tool, resulting in 23165 transistors. The power consumption and delay factor have been evaluated by means of H-Spice toolset in 90nm manufacturing technology. According to the exper- imental results the proposed asynchronous design consumes less power than synchronous scheme by removing clock sig- nals. The imposed area overhead of asynchronous design is reported 36% higher than synchronous one. Copyright 2014 ACM.

关键词： Network-on-chip

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Reduction of ML decoding complexity for MIMO sphere decoding, QOSTBC, and OSTBC

Reduction of ML decoding complexity for MIMO sphere decoding...

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2008 Information Theory and Applications Workshop - ITA

作者： Azzam, Luay Ayanoglu, Ender Center for Pervasive Communications and Computing Department of Electrical Engineering and Computer Science University of California Irvine United States

ISBN: (纸本)1424426707

In this paper, we discuss three applications of the QR decomposition algorithm to decoding in a number of Multi-Input Multi-Output (MIMO) systems. In the first application, we propose a new structure for MIMO Sphere Decoding (SD). We show that the new approach achieves 80% reduction in the overall complexity compared to conventional SD for a 2 × 2 system, and almost 50% reduction for the 4 × 4 and 6 × 6 cases. In the second application, we propose a low complexity Maximum Likelihood Decoding (MLD) algorithm for quasiorthogonal space-time block codes (QOSTBCs). We show that for N = 8 transmit antennas and 16-QAM modulation scheme, the new approach achieves > 97% reduction in the overall complexity compared to conventional MLD, and > 89% reduction compared to the most competitive reported algorithms in the literature. This complexity gain becomes greater when the number of transmit antennas (N) or the constellation size (L) becomes larger. In the third application, we propose a low complexity Maximum Likelihood Decoding (MLD) algorithm for orthogonal space-time block codes (OSTBCs) based on the real-valued lattice representation and QR decomposition. For a system employing the well-known Alamouti OSTBC and 16-QAM modulation scheme, the new approach achieves > 87% reduction in the overall complexity compared to conventional MLD. Moreover, we show that for square L-QAM constellations, the proposed algorithm reduces the decoding computational complexity from O(LN/2) for conventional MLD to O(L) for systems employing QOSTBCs and from O(L) for conventional MLD to O(√L) for those employing OSTBCs without sacrificing the performance.

关键词： Antennas

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Modeling of handoffs and performance analysis of wireless data networks

Modeling of handoffs and performance analysis of wireless da...

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International Conference on Parallel Processing Workshops, ICPPW 2001

作者： Zeng, Qing-An Agrawal, D.P. Center for Distributed and Mobile Computing Department of Electrical and Computer Engineering and Computer Science University of Cincinnati OH45221-0030 United States

ISBN: (纸本)0769512607

In this paper, we introduce a handoff scheme for data mobile cellular radio systems. A steady-stale traffic model is established and an analytical model of the system performance is presented. Average queue length and transmission delay are evaluated. Although mobile users holding channels move from one cell to another, there is almost no packet loss except for the negligibly small blocking probability because a channel request can be transferred from the queue of one base station to another. © 2001 IEEE.

关键词： Quality of service

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Robust Optimal Higher-order-observer-based Dynamic Sliding Mode Control for VTOL Unmanned Aerial Vehicles

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International Journal of Automation and computing 2021年第5期18卷 802-813页

作者： Yashar Mousavi Amin Zarei Arash Mousavi Mohsen Biari Department of Applied Science School of ComputingEngineering and Built EnvironmentGlasgow Caledonian UniversityGlasgow G4 OBAUK Department of Electrical and Computer Engineering University of Sistan and BaluchestanZahedan ***Iran Department Electrical Engineering and Applied Sciences Paradise Research CenterJahrom ***Iran Faculty of Electrical and Robotic Engineering Shahrood University of TechnologyShahrood ***Iran

This paper investigates the precise trajectory tracking of unmanned aerial vehicles(UAV) capable of vertical take-off and landing(VTOL) subjected to external disturbances. For this reason, a robust higher-order-observer-based dynamic sliding mode controller(HOB-DSMC) is developed and optimized using the fractional-order firefly algorithm(FOFA). In the proposed scheme, the sliding surface is defined as a function of output variables, and the higher-order observer is utilized to estimate the unmeasured variables,which effectively alleviate the undesirable effects of the chattering phenomenon. A neighboring point close to the sliding surface is considered, and as the tracking error approaches this point, the second control is activated to reduce the control input. The stability analysis of the closed-loop system is studied based on Lyapunov stability theorem. For a better study of the proposed scheme, various trajectory tracking tests are provided, where accurate tracking and strong robustness can be simultaneously ensured. Comparative simulation results validate the proposed control strategy′s effectiveness and its superiorities over conventional sliding mode controller(SMC) and integral SMC approaches.

关键词： Unmanned aerial vehicle dynamic sliding mode trajectory tracking fractional firefly algorithm vertical take-off and landing system

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Diversity analysis of bit-interleaved coded multiple beamforming

Diversity analysis of bit-interleaved coded multiple beamfor...

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2009 IEEE International Conference on Communications, ICC 2009

作者： Hong, Ju Park Ayanoglu, Ender Center for Pervasive Communications and Computing Department of Electrical Engineering and Computer Science University of California Irvine CA United States

ISBN: (纸本)9781424434350

In this paper, diversity analysis of bit-interleaved coded multiple beamforming (BICMB) is extended to the case of general spatial interleavers, removing a condition on their previously known design criteria and quantifying the resulting diversity order. The diversity order is determined by a parameter Qmax which is inherited from the convolutional code and the spatial de-multiplexer used in BICMB. We introduce a method to find this parameter by employing a transfer function approach as in finding the weight spectrum of a convolutional code. By using this method, several Qmax values are shown and verified to be identical with the results from a computer search. The diversity analysis and the method to find the parameter are supported by simulation results. By using the Singleton bound, we also show that Q max is lower bounded by the product of the number of streams and the code rate of an encoder. The design rule of the spatial de-multiplexer for a given convolutional code is proposed to meet the condition on the maximum achievable diversity order. ©2009 IEEE.

关键词： Convolutional codes

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A reliable active scanning scheme for the IEEE 802.11 MAC layer handoff

A reliable active scanning scheme for the IEEE 802.11 MAC la...

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2003 IEEE Radio and Wireless Conference, RAWCON 2003

作者： Li, Wei Zeng, Qing-An Agrawal, D.P. Center of Distributed and Mobile Computing Department of Electrical and Computer Engineering and Computer Science University of Cincinnati CincinnatiOH45221-0030 United States

ISBN: (纸本)0780378296

In the IEEE 802.11 wireless local area networks (WLANs) with fixed access points (APs), handoff occurs when a mobile station (MS) with a communication in progress changes its associated AP from one to another. It is important to minimize the handoff latency because the active communications of a MS are interrupted before the handoff completes. Such a design needs to take into consideration the high error rate of WLANs. The IEEE 802.11 medium access control (MAC) protocol recommends an active scanning mode for the handoff process. The probe delay of the active scanning may increase greatly if the probe request is lost. However, the successful transmission of the probe request is very unpredictable due to the high collision probability and the lack of any acknowledgement. In this paper, we propose a highly reliable active scanning scheme which can be implemented with the current IEEE 802.11 channel scanning procedure. It is indicated to efficiently increase the reliability of channel scanning, especially in a noisy environment, by performing the probe request loss detection and retransmission. Furthermore, the proposed scheme reduces the overall handoff latency by providing a higher priority for management frames over data frames. © 2003 IEEE.

关键词： Probes

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A survey on software defined networking and its applications

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Frontiers of computer science 2015年第6期9卷 827-845页

作者： Yili GONG Wei HUANG Wenjie WANG Yingchun LEI Computer School Wuhan University Wuhan 430072 China Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor 48109 USA Simulation Training Center Chongqing Communication Institute Chongqing 400035 China Institute of Computing Technology Chinese Academy of Sciences Beijing 100080 China

Software defined networking （SDN） achieves network routing management with logically centralized con- trol software that decouples the network data plane from the control plane. This new design paradigm greatly emancipates network innovation. This paper introduces the background of SDN technology with its design principles, explains its differentiation, and summarizes the research efforts on SDN network architecture, components and applications. Based on the observation of current SDN development, this paper ana- lyzes the potential driving forces of SDN deployment and its future trend.

关键词： software defined networking (SDN) OpenFlow

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