LCS & GBML Central

Research on network structural balance has been of great concern to scholars from diverse fields. In this paper, a two-step approach is proposed for the first time to address the network structural balance problem. The proposed approach involves evolutionary multiobjective optimization, followed by model selection. In the first step, an improved version of the multiobjective discrete particle swarm optimization framework developed in our previous work is suggested. The suggested framework is then employed to implement network multiresolution clustering. In the second step, a problem-specific model selection strategy is devised to select the best Pareto solution (PS) from the Pareto front produced by the first step. The best PS is then decoded into the corresponding network community structure. Based on the discovered community structure, imbalanced edges are determined. Afterward, imbalanced edges are flipped so as to make the network structurally balanced. Extensive experiments on synthetic and real-world signed networks demonstrate the effectiveness of the proposed approach.

In an estimation of distribution algorithm (EDA), global population distribution is modeled by a probabilistic model, from which new trial solutions are sampled, whereas individual location information is not directly and fully exploited. In this paper, we suggest to combine an EDA with cheap and expensive local search (LS) methods for making use of both global statistical information and individual location information. In our approach, part of a new solution is sampled from a modified univariate histogram probabilistic model and the rest is generated by refining a parent solution through a cheap LS method that does not need any function evaluation. When the population has converged, an expensive LS method is applied to improve a promising solution found so far. Controlled experiments have been carried out to investigate the effects of the algorithm components and the control parameters, the scalability on the number of variables, and the running time. The proposed algorithm has been compared with two state-of-the-art algorithms on two test suites of 27 test instances. Experimental results have shown that, for simple test instances, our algorithm can produce better or similar solutions but with faster convergence speed than the compared methods and for some complicated test instances it can find better solutions.

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Most researchers employed common functional models when managing scheduling problems with controllable processing times. However, in many complicated manufacturing systems with a high diversity of jobs, these functional resource models fail to reflect their specific characteristics. To fulfill these requirements, we apply a more general model, the discrete model. Traditional functional models can be viewed as special cases of such model. In this paper, the discrete model is implemented on a problem of minimizing the weighted resource allocation subject to a common deadline on a single machine. By reducing the problem to a partition problem, we demonstrate that it is NP-complete, which addresses the difficult issue of the guarantee of both the solution quality and time cost. In order to tackle the problem, we develop an estimation of distribution algorithm based on an approximation of the Boltzmann distribution. The approximation strategy represents a tradeoff between complexity and solution accuracy. The results of the experiments conducted on benchmarks show that, compared with other alternative approaches, the proposed algorithm has competitive behavior, obtaining 74 best solutions out of 90 instances.

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.

Evolutionary algorithms (EAs) are a large family of heuristic optimization algorithms. They are problem independent and have been applied in various optimization problems. Thus, general analysis tools are especially appealing for guiding the analysis of EAs in various situations. This paper develops the switch analysis approach for running time analysis of EAs, revealing their average computational complexity. Unlike previous analysis approaches that analyze an algorithm from scratch, the switch analysis makes use of another well-analyzed algorithm and, by contrasting them, can lead to better results. We investigate the power of switch analysis by comparing it with two commonly used analysis approaches, the fitness level method and the drift analysis. We define the reducibility between two analysis approaches for comparing their power. By the reducibility relationship, it is revealed that both the fitness level method and the drift analysis are reducible to the switch analysis, as they are equivalent to specific configurations of the switch analysis. We further show that the switch analysis is not reducible to the fitness level method, and compare it with the drift analysis on a concrete analysis case (the discrete linear problem). The reducibility study might shed some light on the unified view of different running time analysis approaches.

Presents a listing of reviewers who contributed to the publication in 2014-2015.

Evolutionary algorithms (EAs) have shown to be promising in solving many-objective optimization problems (MaOPs), where the performance of these algorithms heavily depends on whether solutions that can accelerate convergence toward the Pareto front and maintaining a high degree of diversity will be selected from a set of nondominated solutions. In this paper, we propose a knee point-driven EA to solve MaOPs. Our basic idea is that knee points are naturally most preferred among nondominated solutions if no explicit user preferences are given. A bias toward the knee points in the nondominated solutions in the current population is shown to be an approximation of a bias toward a large hypervolume, thereby enhancing the convergence performance in many-objective optimization. In addition, as at most one solution will be identified as a knee point inside the neighborhood of each solution in the nondominated front, no additional diversity maintenance mechanisms need to be introduced in the proposed algorithm, considerably reducing the computational complexity compared to many existing multiobjective EAs for many-objective optimization. Experimental results on 16 test problems demonstrate the competitiveness of the proposed algorithm in terms of both solution quality and computational efficiency.

Provides a listing of board members, committee members and society officers.

Provides a listing of the editors, board members, and current staff for this issue of the publication.