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作者： Alejandro S. Sena Merson Reyes NAVAL POSTGRADUATE SCHOOL

学位级别：硕士

This project examined the potential impact of process savings achieved through strategically sourced contracts on the Air Force Installation Contracting Agency's (AFICA) manpower. The project leveraged AFICA's contract man-hour data to make logical inferences concerning the transaction costs of various strategically sourced contracts. The information derived from the transaction cost analysis was used to construct a theoretical linear program (LP) to optimize manpower with respect to man- hour savings achieved through strategically sourced contracts. The optimized manpower solution provides a theoretical framework to identify manpower savings that may be used to address AFICA mission objectives.

关键词： Air Force Installation Contracting Agency (AFICA) manpower process savings strategic sourcing linear program optimization

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Solving linear program as linear system in polynomial time

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MATHEMATICAL AND COMPUTER MODELLING 2011年第5-6期53卷 1056-1073页

作者： Sen, Syamal K. Ramakrishnan, Suja Agarwal, Ravi P. Florida Inst Technol Dept Math Sci Melbourne FL 32901 USA

A physically concise polynomial-time iterative-cum-non-iterative algorithm is presented to solve the linear program (LP) Min c(t)chi subject to A chi = b, chi >= 0. The iterative part - a variation of Karmarkar projective transformation algorithm - is essentially due to Barnes only to the extent of detection of basic variables of the LP taking advantage of monotonic convergence. It involves much less number of iterations than those in the Karmarkar projective transformation algorithm. The shrunk linear system containing only the basic variables of the solution vector x resulting from A chi = b is then solved in the mathematically non-iterative part. The solution is then tested for optimality and is usually more accurate because of reduced computation and has less computational and storage complexity due to smaller order of the system. The computational complexity of the combination of these two parts of the algorithm is polynomial-time O(n(3)). The boundedness of the solution, multiple solutions, and no-solution (inconsistency) cases are discussed. The effect of degeneracy of the primal linear program and/or its dual on the uniqueness of the optimal solution is mentioned. The algorithm including optimality test is implemented in Matlab which is found to be useful for solving many real-world problems. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Barnes algorithm Error-free computation linear program linear system Matlab program Polynomial-time iterative-cum-non-iterative algorithm

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Optimal load balanced clustering in homogeneous wireless sensor networks

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2017年第10期30卷 n/a-N.PAG页

作者： Souissi, Manel Meddeb, Aref Univ Tunis El Manar Natl Engn Sch Tunis Tunis Tunisia Univ Sousse Natl Engn Sch Sousse Sousse Tunisia

Balancing the load among sensor nodes is a major challenge for the long run operation of wireless sensor networks. When a sensor node becomes overloaded, the likelihood of higher latency, energy loss, and congestion becomes high. In this paper, we propose an optimal load balanced clustering for hierarchical cluster-based wireless sensor networks. We formulate the network design problem as mixed-integer linear programming. Our contribution is 3-fold: First, we propose an energy aware cluster head selection model for optimal cluster head selection. Then we propose a delay and energy-aware routing model for optimal inter-cluster communication. Finally, we propose an equal traffic for energy efficient clustering for optimal load balanced clustering. We consider the worst case scenario, where all nodes have the same capability and where there are no ways to use mobile sinks or add some powerful nodes as gateways. Thus, our models perform load balancing and maximize network lifetime with no need for special node capabilities such as mobility or heterogeneity or pre-deployment, which would greatly simplify the problem. We show that the proposed models not only increase network lifetime but also minimize latency between sensor nodes. Numerical results show that energy consumption can be effectively balanced among sensor nodes, and stability period can be greatly extended using our models.

关键词： clustering hierarchical routing linear program optimization wireless sensor networks

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A System for Optimal Design of Pressure Constrained Branched Piped Water Networks

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Procedia Engineering 2017年 186卷 349-356页

作者： N. Hooda O. Damani Department of Computer Science and Engineering Indian Institute of Technology Bombay Mumbai India

Rural water networks in the developing world are typically branched networks with a single water source. The main design decision to be made for such networks is the choice of pipe diameters from a discrete set of commercially available pipe diameters. Larger the pipe diameters, better the service (pressure), but higher is the capital cost. In general, each link (connection between two nodes) in the network can consist of several pipe segments of differing diameters. For such networks, existing design tools solve the constrained-optimization problem heuristically [1] [2] . In [3] , an ILP formulation is proposed for the special case of one pipe diameter per link. This means that currently one can either get an optimal solution for the special case of one piped segment per link or get a non-optimal solution for the general case of multiple pipe segments per link. In this work, we come up with a model that solves the general formulation while still maintaining optimality. Our model has an LP formulation. It not only manages to optimally solve the general case, it also has a runtime performance that is better than both the heuristic approach to the general problem as well as the optimal approach to the specific problem (one pipe per link). To aid the designers of piped water networks, we have developed an optimization system called JalTantra that implements this model. It also has GIS functionality integrated for ease of providing network details. It is publicly available at http://***/jaltantra/.

关键词： Water distribution network Network cost optimization linear program

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Quadratic diameter bounds for dual network flow polyhedra

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MATHEMATICAL programMING 2016年第1-2期159卷 237-251页

作者： Borgwardt, Steffen Finhold, Elisabeth Hemmecke, Raymond Tech Univ Munich Munich Germany

Both the combinatorial and the circuit diameter of polyhedra are of interest to the theory of linear programming for their intimate connection to a best-case performance of linear programming algorithms. We study the diameters of dual network flow polyhedra associated to b-flows on directed graphs and prove quadratic upper bounds for both of them: the minimum of and for the combinatorial diameter, and for the circuit diameter. Previously, bounds on these diameters have only been known for bipartite graphs. The situation is much more involved for general graphs. In particular, we construct a family of dual network flow polyhedra with members that violate the circuit diameter bound for bipartite graphs by an arbitrary additive constant.

关键词： Combinatorial diameter Circuit diameter Hirsch conjecture Edges Circuits Graver basis linear program Integer program

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Joint Power Allocation and User Association Optimization for Massive MIMO Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2016年第9期15卷 6384-6399页

作者： Trinh Van Chien Bjornson, Emil Larsson, Erik G. Linkoping Univ Dept Elect Engn ISY S-58183 Linkoping Sweden

This paper investigates the joint power allocation and user association problem in multi-cell Massive MIMO (multiple-input multiple-output) downlink (DL) systems. The target is to minimize the total transmit power consumption when each user is served by an optimized subset of the base stations (BSs), using non-coherent joint transmission. We first derive a lower bound on the ergodic spectral efficiency (SE), which is applicable for any channel distribution and precoding scheme. Closed-form expressions are obtained for Rayleigh fading channels with either maximum ratio transmission (MRT) or zero forcing (ZF) precoding. From these bounds, we further formulate the DL power minimization problems with fixed SE constraints for the users. These problems are proved to be solvable as linear programs, giving the optimal power allocation and BS-user association with low complexity. Furthermore, we formulate a max-min fairness problem that maximizes the worst SE among the users, and we show that it can be solved as a quasi-linear program. Simulations manifest that the proposed methods provide good SE for the users using less transmit power than in small-scale systems and the optimal user association can effectively balance the load between BSs when needed. Even though our framework allows the joint transmission from multiple BSs, there is an overwhelming probability that only one BS is associated with each user at the optimal solution.

关键词： Massive MIMO user association power allocation load balancing linear program

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Joint Routing and Links Scheduling in Two-Tier Multi-Hop RF-Energy Harvesting Networks

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IEEE COMMUNICATIONS LETTERS 2016年第9期20卷 1864-1867页

作者： Chin, Kwan-Wu Wang, Luyao Soh, Sieteng Univ Wollongong Wollongong NSW 2522 Australia Curtin Univ Perth WA 6102 Australia

This letter considers a two-tiered multi-hop RF-harvesting network comprising of wireless routers and so called eh-nodes that harvest energy from RF emitted by the said routers. Our aim is to derive the shortest possible superframe or time division multiple access schedule for use by routers, which are responsible for meeting flow and energy demands. We present a linear program to derive the optimal schedule whilst satisfying the said demands. We also outline a heuristic algorithm called Algo-TS to generate transmission sets. Our results show Algo-TS produces superframes that are at most 2% longer than the optimal solution in all tested scenarios.

关键词： Wireless power transfer linear program schedule length RF energy harvesting

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Peak-Error-Constrained Sparse FIR Filter Design Using Iterative L₁ Optimization 24

Peak-Error-Constrained Sparse FIR Filter Design Using Iterat...

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24th European Signal Processing Conference (EUSIPCO)

作者： Jiang, Aimin Kwan, Hon Keung Zhu, Yanping Liu, Xiaofeng Xu, Ning Yao, Xiao Hohai Univ Coll Internet Things Engn Changzhou Peoples R China Univ Windsor Dept Elect & Comp Engn Windsor ON Canada Changzhou Univ Sch Informat Sci & Engn Changzhou Peoples R China

ISBN: (纸本)9780992862657

In this paper, a novel algorithm is presented for the design of sparse linear-phase FIR filters. Compared to traditional l(1)-optimization-based methods, the proposed algorithm minimizes l(1) norm of a portion (instead of all) of nonzero coefficients. In this way, some nonzero coefficients at crucial positions are not affected by l(1) norm utilized in the objective function. The proposed algorithm employs an iterative procedure and the index set of these crucial coefficients is updated in each iteration. Simulation results demonstrate that the proposed algorithm can achieve better design results than both greedy methods and traditional l(1)-optimization-based methods.

关键词： FIR filters iterative l(1) optimization l(0) norm linear program sparsity

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DEAR: Delay and Energy Aware Routing In Wireless Sensor Networks 12

DEAR: Delay and Energy Aware Routing In Wireless Sensor Netw...

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12th International Wireless Communications & Mobile Computing Conference (IWCMC)

作者： Souissi, Manel Meddeb, Aref Univ Tunis EL Manar Natl Engn Sch Tunis Tunis 1002 Tunisia Univ Sousse Natl Engn Sch Sousse Route Ceinture Sahloul Sousse 4054 Tunisia

ISBN: (纸本)9781509003044

One of the critical issues in a Wireless Sensor Network (WSN) is the design of a proper routing protocol. While the requirement of low latency and low-energy consumption is getting more and more importance in emerging applications, the WSN should be capable of fulfilling its mission in a timely manner and without loss of energy. In this paper, we focus on multi-hop flat routing. A mathematical model for Delay and Energy Aware Routing (DEAR) is proposed. Our model aims to build a trade-off between energy consumption and delay. The goal is to find out a route from all sensor nodes to the base station, which has a comparably lower overall distance, with fewer data forwards. We define a multi-objective function for simultaneously minimizing the distance and minimizing the delay in forwarding. To demonstrate the effectiveness of DEAR, we compare it with the LeeMoon (Lee and Moon Model), the MHRM (Minimum Hop Routing Model), and the MTEM (Minimum Transmission Energy Model). the numerical results show that our model outperforms those models in terms of latency and energy consumption.

关键词： Wireless sensor networks Routing Optimization linear program Energy Latency

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A PTAS for the Multiple Parallel Identical Multi-stage Flow-Shops to Minimize the Makespan 10th

A PTAS for the Multiple Parallel Identical Multi-stage Flow-...

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10th International Frontiers of Algorithmics Workshop (FAW)

作者： Tong, Weitian Miyano, Eiji Goebel, Randy Lin, Guohui Georgia Southern Univ Dept Comp Sci Statesboro GA 30460 USA Kyushu Inst Technol Dept Syst Design & Informat Iizuka Fukuoka 8208502 Japan Univ Alberta Dept Comp Sci Edmonton AB T6G 2E8 Canada

ISBN: (纸本)9783319398174;9783319398167

In the parallel k-stage flow-shops problem, we are given m identical k-stage flow-shops and a set of jobs. Each job can be processed by any one of the flow-shops but switching between flow-shops is not allowed. The objective is to minimize the makespan, which is the finishing time of the last job. This problem generalizes the classical parallel identical machine scheduling (where k = 1) and the classical flow-shop scheduling (where m = 1) problems, and thus it is NP-hard. We present a polynomial-time approximation scheme for the problem, when m and k are fixed constants. The key technique is to enumerate over schedules for big jobs, solve a linear programming for small jobs, and add the fractional small jobs at the end. Such a technique has been used in the design of similar approximation schemes.

关键词： Multiprocessor scheduling Flow-shop scheduling Makespan linear program Polynomial-time approximation scheme

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