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23rd Asia-Pacific Conference on Communications (APCC) - Bridging the Metropolitan and the Remote

作者： Lin, Jingran Zhao, Ruiming Univ Elect Sci & Technol China Sch Commun & Informat Engn Chengdu 611731 Sichuan Peoples R China

ISBN: (纸本)9781740523905

Consider a network consisting of one multi-antenna base station (BS) and multiple single-antenna users. With a lot of users awaiting service, the network tends to be congested and the quality of service (QoS) degrades remarkably. This promotes the research on user admission control;i.e., to guarantee QoS, the network serves only a subset of users and rejects the rest. In this paper, we consider a max-min fairness (MMF) problem based on joint admission control and beamforming. In particular, by jointly optimizing the admissible users and the transmit beam formers, we maximize the minimum signal-to-interference-plus-noise-ratio (SINR) of admissible users, such that high QoS and fairness can be guaranteed for them. This problem is essentially NP-hard, and hence we develop a low-complexity iterative deflation algorithm to obtain some efficient approximate solution. In each iteration, we improve the users' SINRs and drop the user with the lowest SINR-to-power ratio, until the given user number is achieved. To facilitate the algorithm implementation, especially in large-scale networks, we further employ the alternating direction method of multipliers (ADMM) to perform per-user optimization. Finally, an efficient distributed algorithm is developed, with each step being solved in closed form.

关键词： Interference Signal to noise ratio Admission control Approximation algorithms distributed algorithms Complexity theory

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Competitive access in multi-RAT systems with regulated interference constraints

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Science China(Information Sciences) 2017年第2期60卷 96-106页

作者： Ning WEI Zhongpei ZHANG National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China

Deployment of multiple radio access technologies(RATs) at the same cell site enables the system to flexibly support different types of devices and services. Such multi-RAT systems call for an efficient utilization of the system resources as well as simplified management. In this paper, we take a user-centric approach and let each individual user equipment decide its own access strategy in a multi-RAT system with regulated interference constraints. The formulated problem is a generalized Nash equilibrium(GNE) problem. We show that there always exists a GNE but its uniqueness is not guaranteed. A closed form solution is provided to characterize a special class of the GNEs. We then propose a primal-dual algorithm with detailed convergence analysis for computing a GNE. The proposed algorithm may have practical implications in the design of multi-RAT systems.

关键词： 5G multi-RAT systems multiple access distributed algorithms generalized Nash equilibrium

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A Time- and Message-Optimal distributed Algorithm for Minimum Spanning Trees 2017

A Time- and Message-Optimal Distributed Algorithm for Minimu...

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49th Annual ACM-SIGACT Symposium on Theory of Computing (STOC)

作者： Pandurangan, Gopal Robinson, Peter Scquizzato, Michele Univ Houston Houston TX 77004 USA Royal Holloway Univ London London England

ISBN: (纸本)9781450345286

This paper presents a randomized (Las Vegas) distributed algorithm that constructs a minimum spanning tree (MST) in weighted networks with optimal (up to polylogarithmic factors) time and message complexity. This algorithm runs in (O) over tilde (D + root n) time and exchanges (O) over tilde (m) messages (both with high probability), where n is the number of nodes of the network, D is the diameter, and m is the number of edges. This is the first distributed MST algorithm that matches simultaneously the time lower bound of (Omega) over tilde (D + root n) [Elkin, SIAM J. Comput. 2006] and the message lower bound of Omega(m) [Kutten et al., J. ACM 2015], which both apply to randomized Monte Carlo algorithms. The prior time and message lower bounds are derived using two completely different graph constructions;the existing lower bound construction that shows one lower bound does not work for the other. To complement our algorithm, we present a new lower bound graph construction for which any distributed MST algorithm requires both (Omega) over tilde (D + root n) rounds and Omega(m) messages.

关键词： distributed algorithms Minimum spanning trees

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Finite-Time distributed Optimization with Quadratic Objective Functions under Uncertain Information 56

Finite-Time Distributed Optimization with Quadratic Objectiv...

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56th Annual IEEE Conference on Decision and Control (CDC)

作者： Feng, Zhi Hu, Guoqiang Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

ISBN: (纸本)9781509028733

This paper presents distributed algorithms for finite-time convex optimization problem of multi-agent systems. The uncertain information comes from the noise corruption or interference in the communication as well as computation performed by the agents. The objective is to design distributed algorithms so that a team of agents, each with its own private cost function and communicating over an undirected graph, seeks to minimize the sum of local objective functions in a finite time. Specifically, a distributed algorithm with robust consensus strategies is proposed to solve this distributed optimization problem so that the optimal solution can be estimated in a finite time. The developed algorithm is applied to the economic dispatch problem and it shows that under the proposed algorithms, the optimal solution can be achieved in a finite time, while satisfying both the global generation-demand constraints and local generation capacity constraints.

关键词： Optimization Robustness Linear programming Economics Algorithm design and analysis distributed algorithms Convergence

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distributed Automatic Differentiation for Ptychography

Distributed Automatic Differentiation for Ptychography

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International Conference on Computational Science (ICCS)

作者： Nashed, Youssef S. G. Peterka, Tom Deng, Junjing Jaeobsen, Chris Argonne Natl Lab Math & Comp Sci Div Argonne IL 60439 USA Argonne Natl Lab Adv Photon Source Argonne IL 60439 USA Northwestern Univ Dept Elect Engn & Comp Sci Evanston IL 60208 USA Northwestern Univ Dept Phys & Astron Evanston IL 60208 USA

Synchrotron radiation light source facilities are leading the way to ultrahigh resolution X-ray imaging. High resolution imaging is essential to understanding the fundamental structure and interaction of materials at the smallest length scale possible. Diffraction based methods achieve nanoscale imaging by replacing traditional objective lenses by pixelated area detectors and computational image reconstruction. Among these methods, ptychography is quickly becoming the standard for sub-30 nanometer imaging of extended samples, but at the expense of increasingly high data rates and volumes. This paper presents a new distributed algorithm for solving the ptychographic image reconstruction problem based on automatic differentiation. Input datasets are subdivided between multiple graphics processing units (GPUs);each subset of the problem is then solved either entirely independent of other subsets (asynchronously) or through sharing gradient information with other GPUs (synchronously). The algorithm was evaluated on simulated and real data acquired at the Advanced Photon Source, scaling up to 192 GPUs. The synchronous variant of our method outperformed an existing multi-GPU implementation in terms of accuracy while running at a comparable execution time. (C) 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the International Conference on Computational Science

关键词： inverse problems image reconstruction gradient methods distributed algorithms X-ray scattering

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Computationally Efficient, Dynamic distributed Algorithm of Sensor-based Big Data 13

Computationally Efficient, Dynamic Distributed Algorithm of ...

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13th International Wireless Communications and Mobile Computing Conference (IWCMC)

作者： Al-kahtani, Mohammed S. Karim, Lutful Almhana, Jalal Prince Sattam bin Abdulaziz Univ Dept Comp Engn Al Kharj Saudi Arabia Seneca Coll Appl Arts & Technol Toronto ON Canada Moncton Univ Dept Comp Sci Moncton NB Canada

ISBN: (纸本)9781509043729

With the emergence of big data, designing an efficient distributed algorithm is significantly important. While most existing distributed algorithms consider distributed processing only for commodity computers, this paper introduces a Computationally Efficient, Dynamic distributed Algorithm (CEDA) for big data processing on a framework that comprises data processing both at the data collection end and data processing at the central server end. The proposed CEDA algorithm works both in low powered nodes and high speed commodity computers. Additionally, it performs sequential and parallel processing based on the amount of data received at the central server. Simulation results demonstrate that the CEDA algorithm achieves processing efficiency in terms of data processing time as compared to traditional distributed algorithms, which do not consider processing data at sensors.

关键词： Big Data distributed algorithms MapReduce Sensor Commodity Hardware

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distributed Balancing under Interval Flow Constraints in Directed Communication Topologies 56

Distributed Balancing under Interval Flow Constraints in Dir...

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56th Annual IEEE Conference on Decision and Control (CDC)

作者： Hadjicostis, Christoforos N. Dominguez-Garcia, Alejandro D. Univ Cyprus Dept Elect & Comp Engn Nicosia Cyprus Univ Illinois Dept Elect & Comp Engn Urbana IL 61801 USA

ISBN: (纸本)9781509028733

In this paper, we propose a distributed algorithm that relies on a strongly connected (but possibly directed) communication topology to achieve admissible and balanced flows in a given network. More specifically, we consider a flow network that is described by a digraph (physical topology), each edge of which can admit a flow within a certain interval. The paper proposes and analyzes a distributed iterative algorithm for computing admissible and balanced flows, i.e., flows that are within the given interval at each edge and balance the total inflow and the total out-flow at each node. Unlike previous work that required a communication topology with bidirectional exchanges between pairs of nodes that are physically connected (i.e., nodes that share an edge in the physical topology), the distributed algorithm we propose only requires a communication topology that matches the physical topology (which is, in general, directed). The proposed algorithm allows the nodes to asymptotically (with geometric rate) compute a set of admissible and balanced flows, as long as such solution exists.

关键词： Topology Network topology distributed algorithms Iterative methods Bidirectional control Upper bound Electronic mail

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A Scalable and distributed Approach for NFV Service Chain Cost Minimization 37

A Scalable and Distributed Approach for NFV Service Chain Co...

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37th IEEE International Conference on distributed Computing Systems (ICDCS)

作者： Zhang, Zijun Li, Zongpeng Wu, Chuan Huang, Chuanhe Wuhan Univ Sch Comp State Key Lab Software Engn Wuhan Hubei Peoples R China Univ Calgary Dept Comp Sci Calgary AB Canada Univ Hong Kong Dept Comp Sci Hong Kong Hong Kong Peoples R China

ISBN: (纸本)9781538617915

Network function virtualization (NFV) represents the latest technology advancement in network service provisioning. Traditional hardware middleboxes are replaced by software programs running on industry standard servers and virtual machines, for service agility, flexibility, and cost reduction. NFV users are provisioned with service chains composed of virtual network functions (VNFs). A fundamental problem in NFV service chain provisioning is to satisfy user demands with minimum system-wide cost. We jointly consider two types of cost in this work: nodal resource cost and link delay cost, and formulate the service chain provisioning problem using nonlinear optimization. Through the method of auxiliary variables, we transform the optimization problem into its separable form, and then apply the alternating direction method of multipliers (ADMM) to design scalable and fully distributed solutions. Through simulation studies, we verify the convergence and efficacy of our distributed algorithm design.

关键词： Servers Optimization Minimization Convex functions Hardware distributed algorithms Bandwidth

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distributed Variational Equilibrium Seeking of Multi-coalition Game via Variational Inequality Approach

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IFAC-PapersOnLine 2017年第1期50卷 940-945页

作者： Zeng X. Liang S. Hong Y. Key Laboratory of Systems and Control Institute of Systems Science Chinese Academy of Sciences Beijing 100190 China

This paper studies the distributed variational equilibrium seeking problem for a class of multi-coalition non-cooperative games via a continuous-time algorithm. In the multi-coalition game, there are multiple coalitions and each coalition (a virtual player in the game) is composed of a set of agents, which are actual decision makers for their coalition and cooperate to minimize the coalition payoff function. To solve this problem, the variational equilibrium seeking problem for a multi-coalition game is first formulated as a distributed variational inequality problem. Then, a novel distributed projected continuous-time algorithm, which is in the form of a projected ordinary differential equation, is proposed to solve the distributed variational inequality. Finally, the algorithm is applied to a numerical example to show the efficacy of the proposed algorithm. © 2017

关键词： distributed algorithms distributed variational equilibria multi-coalition games variational inequalities

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distributed Real Time TDMA Scheduling Algorithm for Tree Topology WSNs

Distributed Real Time TDMA Scheduling Algorithm for Tree Top...

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20th World Congress of the International-Federation-of-Automatic-Control (IFAC)

作者： Ahmad, Aasem Hanzalek, Zdenek Czech Tech Univ FEE DCE Prague Czech Republic Czech Tech Univ FEE DCE CIIRC Prague Czech Republic

In this paper, we address the problem of developing TDMA scheduling algorithm for tree topology WSNs. The data transmissions are organized into periodic data flows that may have opposite directions since they are carrying sensor and actuator values for feedback control. It is required to determine a periodic and collision-free allocation of the time-slots to the sensor nodes such that the end-to-end deadline of each data flow, as given in time units, is satisfied. The objective is to maximize the lifetime of the network by maximizing the time when the nodes are in the sleep mode. However, the longer the time at which the nodes stay in the sleep mode, the harder is to meet the timeliness requirements of the data flows. To solve the TDMA scheduling problem, we have found an elegant approach to express the end-to-end deadline as an integer number of the length of the schedule period. Moreover, since the distributed algorithms, in compassion with the centralized algorithms, well-suit the scarce resources of the WSNs, we focus on the distributed methods that allow each node in the network to come up with its allocated time-slots in the schedule. The proposed algorithm is based on the graph theory algorithms, namely the distributed shortest path and the distributed topological ordering. Furthermore, it falls into the category of the exact algorithms for tree topology with single-collision domain and in the category of the heuristic algorithms for multiple-collision domains tree topology. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： ZigBee cluster-tree WSNs distributed algorithms energy efficiency

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