The linear sum assignment problem has been well studied in combinatorial optimization. Because of the integrality property, it is a linear programming problem with a variety of efficient algorithms to solve it. In the...
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The linear sum assignment problem has been well studied in combinatorial optimization. Because of the integrality property, it is a linear programming problem with a variety of efficient algorithms to solve it. In the given research, we present a reformulation of the linear sum assignment problem and a Lagrangian relaxation algorithm for its reformulation. An important characteristic of the new Lagrangian relaxation method is that the optimal Lagrangian multiplier yields a critical bottleneck value. Lagrangian relaxation has only one Lagrangian multiplier, which can only take on a limited number of values, making the search for the optimal multiplier easy. The interpretation of the optimal Lagrangian parameter is that its value is equal to the price that must be paid for all objects in the problem to be assigned.
Many resource allocation issues in wireless communications can he modeled as assignmentproblems and can be solved online with global information. However, traditional methods for assignmentproblems take a lot of tim...
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Many resource allocation issues in wireless communications can he modeled as assignmentproblems and can be solved online with global information. However, traditional methods for assignmentproblems take a lot of time to find the optimal solutions. In this letter, we solve the assignmentproblem using machine learning approach. Specifically, the linear sum assignment problems (LSAPs) are solved by the deep neural networks (DNNs). Since LSAP is a combinatorial optimization problem, it is first decomposed into several sub-assignmentproblems. Each of them is a classification problem and can be solved effectively with DNNs. Two kinds of DNNs, feed-forward neural network and convolutional neural network, are implemented to deal with the sub-assignmentproblems, respectively. Based on computer simulation, DNNs can effectively solve LSAPs with great time efficiency and only slight loss of accuracy.
In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several us...
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In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several users, and a single eavesdropper that intends to wiretap the transmitted message within each OFDMA subchannel. By taking into consideration the existence of the eavesdropper, the base station aims to assign subchannels and allocate the available power in order to optimize the max-min fairness criterion over the users' secrecy rate. The considered problem is a mixed integer nonlinear program. For a fixed subchannel assignment, the optimal power allocation is obtained by developing an algorithm of polynomial computational complexity. In the general case, the problem is investigated from two different perspectives due to its combinatorial nature. In the first, the number of users is equal or higher than the number of subchannels, whereas in the second, the number of users is less than the number of subchannels. In the first case, we provide the optimal solution in polynomial time by transforming the original problem into an assignment one for which there are polynomial time algorithms. In the second case, the secrecy rate formula is linearly approximated and the problem is transformed to a mixed integer linear program, which is solved by a branch-and-bound algorithm. Moreover, optimality is discussed for two particular cases where the available power tends to infinity and zero, respectively. Based on the resulting insights, three heuristic schemes of polynomial complexity are proposed, offering a better balance between performance and complexity. Simulation results demonstrate that each one of these schemes achieves its highest performance at a different power regime of the system.
In this paper, we focus on the problem of solving large-scale instances of the linear sum assignment problem by auction algorithms. We introduce a modified auction algorithm, called look-back auction algorithm, which ...
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In this paper, we focus on the problem of solving large-scale instances of the linear sum assignment problem by auction algorithms. We introduce a modified auction algorithm, called look-back auction algorithm, which extends the forward auction algorithm by the ability of reusing information from previous bids. We show that it is able to reuse information from the previous bids with high efficiency for all tested types of input instances. We discuss then the design and implementation of a suite of sequential and distributed memory auction algorithms on a Linux cluster with the evaluation on several types of input instances of the linear sum assignment problem. Our results show that the look-back auction algorithm solves sequentially nearly all types of dense instances faster than other evaluated algorithms and it is more stable than the forward-reverse auction algorithm for sparse instances. Our distributed memory auction algorithms are fully memory scalable.
The joint assignment of subcarriers and limited transmission power is addressed as a combinatorial optimization problem in orthogonal frequency division multiple access networks. To ensure fairness among users while j...
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The joint assignment of subcarriers and limited transmission power is addressed as a combinatorial optimization problem in orthogonal frequency division multiple access networks. To ensure fairness among users while jointly minimizing the total transmit power, the minimization of the number of outage subcarriers is considered as the objective function. The proposed scheme enables distinct rate requirement for each user. Optimal and reduced complexity algorithms, based on the application of Hungarian method to randomly weighted complete bipartite graphs, that reduce the outage probability according to the benchmark works while providing considerable power savings are proposed.
A method is presented for optimising the structure of the turbo-code interleaver using the Hungarian method (linear sum assignment problem). Numerical results are presented which show a substantial improvement with re...
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A method is presented for optimising the structure of the turbo-code interleaver using the Hungarian method (linear sum assignment problem). Numerical results are presented which show a substantial improvement with respect to a random interleaver.
We introduce a new algorithm, called the swapping algorithm, to approximate numerically the minimal and maximal expected inner product of two random vectors with given marginal distributions. As a direct application, ...
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We introduce a new algorithm, called the swapping algorithm, to approximate numerically the minimal and maximal expected inner product of two random vectors with given marginal distributions. As a direct application, the algorithm computes an approximation of the L2-Wasserstein distance between two multivariate measures. The algorithm is simple to implement, accurate and less computationally expensive than the algorithms generally used in the literature for this problem. The algorithm also provides a discretized image of optimal measures and can be extended to more general cost functionals. (C) 2017 Elsevier Inc. All rights reserved.
In ACM CCS 2015, Naveed et al. proposed attacks using plaintext auxiliary data for databases encrypted by ordered preserving encryption or more general property preserving encryptions. Their attacks are based on the H...
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ISBN:
(纸本)9783319979168;9783319979151
In ACM CCS 2015, Naveed et al. proposed attacks using plaintext auxiliary data for databases encrypted by ordered preserving encryption or more general property preserving encryptions. Their attacks are based on the Hungarian algorithm for solving the linear sum assignment problem (LSAP). In this work, we define a new assignment optimization problem with an additional condition of order structure and propose a search algorithm for finding its exact solution. We apply the new algorithm to attack an encrypted database in the same situation as Naveed et al. and found that our proposed method improves the success probability of the attacks compared with the attacks of Naveed et al.
In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several us...
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ISBN:
(纸本)9781479950416
In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several users and a single eavesdropper that indents to wiretap the transmitted message within each OFDMA subchannel. By taking into consideration the existence of the eavesdropper, the base station aims to assign subchannels and allocate the available power in order to optimize the max-min fairness criterion over the users' secrecy rate. The investigated problem is hard to be solved because of its combinatorial and nonlinear nature. Thus, optimality is discussed for two particular cases where the available power tends to infinity and zero, respectively. The optimal solution is obtained by formulating a mixed integer linearproblem in the first case and a series of linear sum assignment problems in the second. In addition, two low-complexity solutions are presented which are based on decoupling the subchannel and the power allocation subproblems. Numerical results are provided to illustrate the performance of the presented solutions.
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