NEGO — Group decision support system

There are two major frameworks for decision making: maximizing and satisficing. A combination of both may be used to describe group decision making (GDM). In the satisficing approach, decision makers (DMs) formulate aspiriation levels or demands which take the form of constraints. Choosing from among different decisions, DMs take into account their preferences or wants, which take the form of objective functions.GDM is divided into two stages: first, each DM makes a decision, and second, DMs negotiate so as to achieve a compromise decision. Negotiating is an iterative process. Negotiations are completed when all demands have been met.The group decision support system “NEGO” assists DMs in finding a compromise. It has been used for solving a GDM problem at the corporate level and is currently utilized in management courses.     

A parallel MOEA with criterion-based selection applied to the Knapsack Problem

In this paper, we propose a parallel multiobjective evolutionary algorithm called Parallel Criterion-based Partitioning MOEA (PCPMOEA), with an application to the Multiobjective Knapsack Problem (MOKP). The suggested search strategy is based on a periodic partitioning of potentially efficient solutions, which are distributed to multiple multiobjective evolutionary algorithms (MOEAs). Each MOEA is dedicated to a sole objective, in which it combines both criterion-based and dominance-based approaches. The suggested algorithm addresses two main sub-objectives: minimizing the distance between the current non-dominated solutions and the ideal point, and ensuring the spread of the potentially efficient solutions. Experimental results are included, where we assess the performance of the suggested algorithm against the above mentioned sub-objectives, compared with state-of-the-art results using well-known multi-objective metaheuristics.     

Real-time task scheduling by multiobjective genetic algorithm

Real-time tasks are characterized by computational activities with timing constraints and classified into two categories: a hard real-time task and a soft real-time task. In hard real-time tasks, tardiness can be catastrophic. The goal of hard real-time tasks scheduling algorithms is to meet all tasks’ deadlines, in other words, to keep the feasibility of scheduling through admission control. However, in the case of soft real-time tasks, slight violation of deadlines is not so critical.In this paper, we propose a new scheduling algorithm for soft real-time tasks using multiobjective genetic algorithm (moGA) on multiprocessors system. It is assumed that tasks have precedence relations among them and are executed on homogeneous multiprocessor environment.The objective of the proposed scheduling algorithm is to minimize the total tardiness and total number of processors used. For these objectives, this paper combines adaptive weight approach (AWA) that utilizes some useful information from the current population to readjust weights for obtaining a search pressure toward a positive ideal point. The effectiveness of the proposed algorithm is shown through simulation studies.     

一种基于多目标遗传算法的非线性控制器

该文利用相位滞后仅38.1°的Clegg积分器构成一个非线性比例积分器,并利用多目标遗传算法对该控制器的三个参数进行优化,其中被优化的两个目标分别为被控系统的给定性能指标和抗负载扰动能力。然后将该控制器应用于一个存在饱和特性和间隙特性的双闭环调速系统,研究并比较了该系统在阶跃给定输入下的性能指标以及抗负载扰动的能力。仿真试验表明将该非线性控制器应用于具有多个非线性特性的动态系统能取得优良的性能。     

A multiobjective swarm intelligence approach based on artificial bee colony for reliable DNA sequence design

The design of reliable DNA sequences is crucial in many engineering applications which depend on DNA-based technologies, such as nanotechnology or DNA computing. In these cases, two of the most important properties that must be controlled to obtain reliable sequences are self-assembly and self-complementary hybridization. These processes have to be restricted to avoid undesirable reactions, because in the specific case of DNA computing, undesirable reactions usually lead to incorrect computations. Therefore, it is important to design robust sets of sequences which provide efficient and reliable computations. The design of reliable DNA sequences involves heterogeneous and conflicting design criteria that do not fit traditional optimization methods. In this paper, DNA sequence design has been formulated as a multiobjective optimization problem and a novel multiobjective approach based on swarm intelligence has been proposed to solve it. Specifically, a multiobjective version of the Artificial Bee Colony metaheuristics (MO-ABC) is developed to tackle the problem. MO-ABC takes in consideration six different conflicting design criteria to generate reliable DNA sequences that can be used for bio-molecular computing. Moreover, in order to verify the effectiveness of the novel multiobjective proposal, formal comparisons with the well-known multiobjective standard NSGA-II (fast non-dominated sorting genetic algorithm) were performed. After a detailed study, results indicate that our artificial swarm intelligence approach obtains satisfactory reliable DNA sequences. Two multiobjective indicators were used in order to compare the developed algorithms: hypervolume and set coverage. Finally, other relevant works published in the literature were also studied to validate our results. To this respect the conclusion that can be drawn is that the novel approach proposed in this paper obtains very promising DNA sequences that significantly surpass other results previously published.     

Fast computation of equispaced Pareto manifolds and Pareto fronts for multiobjective optimization problems

In this paper, we consider the problem of generating a well sampled discrete representation of the Pareto manifold or the Pareto front corresponding to the equilibrium points of a multi-objective optimization problem. We show how the introduction of simple additional constraints into a continuation procedure produces equispaced points in either of those two sets. Moreover, we describe in detail a novel algorithm for global continuation that requires two orders of magnitude less function evaluations than evolutionary algorithms commonly used to solve this problem. The performance of the methods is demonstrated on problems from the current literature.     

Three-objective subgraph mining using multiobjective evolutionary programming

The existing methods for graph-based data mining (GBDM) follow the basic approach of applying a single-objective search with a user-defined threshold to discover interesting subgraphs. This obliges the user to deal with simple thresholds and impedes her/him from evaluating the mined subgraphs by defining different “goodness” (i.e., multiobjective) criteria regarding the characteristics of the subgraphs. In previous papers, we defined a multiobjective GBDM framework to perform bi-objective graph mining in terms of subgraph support and size maximization. Two different search methods were considered with this aim, a multiobjective beam search and a multiobjective evolutionary programming (MOEP). In this contribution, we extend the latter formulation to a three-objective framework by incorporating another classical graph mining objective, the subgraph diameter. The proposed MOEP method for multiobjective GBDM is tested on five synthetic and real-world datasets and its performance is compared against single and multiobjective subgraph mining approaches based on the classical Subdue technique in GBDM. The results highlight the application of multiobjective subgraph mining allows us to discover more diversified subgraphs in the objective space.     

采用两步训练法的多目标分布估计算法

提出两步训练法,改进了基于规则模型的多目标分布估计算法.在算法的模型训练环节,首先采用均值分簇法进行初步聚类;然后采用基于流形分簇法进行细致聚类,代替原算法中采用局部主元分析算法需要循环迭代的聚类分簇方法.通过6个Benchmark测试函数验证,改进算法保持了原算法的收敛性和多样性,并缩短了寻优的时间.     

Approximated set-valued mapping approach for handling multiobjective bilevel problems

A significant amount of research has been done on bilevel optimization problems both in the realm of classical and evolutionary optimization. However, the multiobjective extensions of bilevel programming have received relatively little attention from researchers in both the domains. The existing algorithms are mostly brute-force nested strategies, and therefore computationally demanding. In this paper, we develop insights into multiobjective bilevel optimization through theoretical progress made in the direction of parametric multiobjective programming. We introduce an approximated set-valued mapping procedure that would be helpful in the development of efficient evolutionary approaches for solving these problems. The utility of the procedure has been emphasized by incorporating it in a hierarchical evolutionary framework and assessing the improvements. Test problems with varying levels of complexity have been used in the experiments.     

An evolutionary approach to generalized biobjective traveling salesperson problem

We consider the generalized biobjective traveling salesperson problem, where there are a number of nodes to be visited and each node pair is connected by a set of edges. The final route requires finding the order in which the nodes are visited (tours) and finding edges to follow between the consecutive nodes of the tour. We exploit the characteristics of the problem to develop an evolutionary algorithm for generating an approximation of nondominated points. For this, we approximate the efficient tours using approximate representations of the efficient edges between node pairs in the objective function space. We test the algorithm on several randomly-generated problem instances and our experiments show that the evolutionary algorithm approximates the nondominated set well.     

Design and analysis of stochastic local search for the multiobjective traveling salesman problem

Stochastic local search (SLS) algorithms are typically composed of a number of different components, each of which should contribute significantly to the final algorithm's performance. If the goal is to design and engineer effective SLS algorithms, the algorithm developer requires some insight into the importance and the behavior of possible algorithmic components. In this paper, we analyze algorithmic components of SLS algorithms for the multiobjective travelling salesman problem. The analysis is done using a careful experimental design for a generic class of SLS algorithms for multiobjective combinatorial optimization. Based on the insights gained, we engineer SLS algorithms for this problem. Experimental results show that these SLS algorithms, despite their conceptual simplicity, outperform a well-known memetic algorithm for a range of benchmark instances with two and three objectives.     

The two-stage recombination operator and its application to the multiobjective 0/1 knapsack problem: A comparative study

In this paper, we first propose a new recombination operator called the two-stage recombination and then we test its performance in the context of the multiobjective 0/1 knapsack problem (MOKP). The proposed recombination operator generates only one offspring solution from a selected pair of parents according to the following two stages. In the first stage, called genetic shared-information stage or similarity-preserving stage, the generated offspring inherits all parent similar genes (i.e., genes or decision variables having the same positions and the same values in both parents). In the second stage, called problem fitness-information stage, the parent non-similar genes (i.e., genes or decision variables having the same positions but different values regarding the two parents) are selected from one of the two parents using some fitness information. Initially, we propose two different approaches for the second stage: the general version and the restricted version. However, the application of the restricted version to the MOKP leads to an improved version which is more specific to this problem. The general and the MOKP-specific versions of the two-stage recombination are compared against three traditional crossovers using two well-known multiobjective evolutionary algorithms. Promising results are obtained. We also provide a comparison between the general version and the MOKP-specific version.     

多目标0/1背包问题MOEA求解中的修复策略

多目标进化算法在求解多目标0/1背包问题时常使用修复策略来满足容量约束.文中更全面地考虑物品对各个背包的不同影响,提出两种加权修复策略,分别基于背包容量和容量约束违反程度,并应用于经典算法SPEA2中.在9个标准MOKP测试实例上的实验结果表明,采用该修复策略的SPEA2算法能更有效地收敛到Pareto最优前沿.     

ED-LS – A heuristic local search for the multiobjective Firefighter Problem

One of the approaches to combinatorial optimization is to use global search methods, such as evolutionary algorithms combined with local search procedures. Local search can be very effective in improving the quality of solutions, however, searching large neighbourhoods can be computationally expensive. In this paper a new local search method is described that is dedicated to the Firefighter Problem (FFP). The Firefighter Problem concerns protecting nodes of a graph in order to stop a threat that is spreading in the graph. Because the resources used for protection are limited, the goal is to find the best order in which the nodes are protected and thus the FFP is a combinatorial optimization problem. One of the key elements in the design of a local search method is the definition of the neighbourhoods of solutions from which the local search starts. The method proposed in this paper (ED-LS) aims at lowering the computational cost of the local search by reducing, based on certain heuristics, the size of these neighbourhoods.In this paper the ED-LS is compared to an optimization without the local search, a local search using non-reduced neighbourhoods and a method that reduces the neighbourhood by checking only some randomly selected neighbours. The results show that the ED-LS improves the performance of the algorithm with respect to no local search at all and to the local search using non-reduced neighbourhoods, supporting the view that reducing the size of the neighbourhood is beneficial. Also, the ED-LS produces better results than when the size of the neighbourhood is reduced randomly, which means that the proposed heuristics are indeed selecting promising neighbours effectively. In the last part of the experiments the ED-LS is further improved to obtain faster improvement of solutions at the beginning of the optimization run.     

基于Dempster-Shafer的飞行机器人多目标视觉定位方法

在受到遮挡物影响的室内环境中,飞行机器人接收数据中常伴有不确定性因素,为了解决复杂室内环境下高精准定位问题,提出了基于Dempster-Shafer的飞行机器人多目标视觉定位方法。根据飞行机器人控制原理,分析飞行位置与期望位置存在偏差,通过提取颜色特征和边缘特征建立多目标模型。设计地面标记,采用迭代算法对标记地面目标进行局部最大化概率计算,以此适应多目标形变,通过Dempster-Shafer证据推理方法获取目标精准位置,由此完成多目标视觉定位。在实验场地支持下,将传统方法与Dempster-Shafer证据推理方法进行对比分析,由结果可知,Dempster-Shafer证据推理方法定位精准度最高可达到96%,对提高室内定位精准度具有一定价值。     

模拟退火算法与遗传算法结合及多目标优化求解研究

多目标优化问题是目前遗传算法应用研究的一个重点。本文针对经典遗传算法在多目标优化计算中,难以获得足够的比较均匀的Ｐａｒｅｔｏ优集的不足,提出一种热力学遗传算法,研究热力学中熵和温度的概念,并综合利用约束交叉、适应度共享技术来进行目标函数的优化计算。实验结果显示,这种改进型遗传算法能得到一个较好的Ｐａｒｅｔｏ优集。     

WBMOAIS: A novel artificial immune system for multiobjective optimization

This study presents a novel weight-based multiobjective artificial immune system (WBMOAIS) based on opt-aiNET, the artificial immune system algorithm for multi-modal optimization. The proposed algorithm follows the elementary structure of opt-aiNET, but has the following distinct characteristics: (1) a randomly weighted sum of multiple objectives is used as a fitness function. The fitness assignment has a much lower computational complexity than that based on Pareto ranking, (2) the individuals of the population are chosen from the memory, which is a set of elite solutions, and a local search procedure is utilized to facilitate the exploitation of the search space, and (3) in addition to the clonal suppression algorithm similar to that used in opt-aiNET, a new truncation algorithm with similar individuals (TASI) is presented in order to eliminate similar individuals in memory and obtain a well-distributed spread of non-dominated solutions. The proposed algorithm, WBMOAIS, is compared with the vector immune algorithm (VIS) and the elitist non-dominated sorting genetic system (NSGA-II) that are representative of the state-of-the-art in multiobjective optimization metaheuristics. Simulation results on seven standard problems (ZDT6, SCH2, DEB, KUR, POL, FON, and VNT) show WBMOAIS outperforms VIS and NSGA-II and can become a valid alternative to standard algorithms for solving multiobjective optimization problems.     

Numerical treatment of multiobjective optimal control problems

We present a numerical procedure for solving optimal control problems with both linear terminal constraints and multiple criteria. Using a Chebyshev spectral procedure, the problem reduces to a constrained optimization problem which can be solved using hybrid penalty partial quadratic interpolation (HPPQI) technique. The proposed procedure compares quite favorably with other methods on a sample of well-known examples.     

A symbolic fault-prediction model based on multiobjective particle swarm optimization

In the literature the fault-proneness of classes or methods has been used to devise strategies for reducing testing costs and efforts. In general, fault-proneness is predicted through a set of design metrics and, most recently, by using Machine Learning (ML) techniques. However, some ML techniques cannot deal with unbalanced data, characteristic very common of the fault datasets and, their produced results are not easily interpreted by most programmers and testers. Considering these facts, this paper introduces a novel fault-prediction approach based on Multiobjective Particle Swarm Optimization (MOPSO). Exploring Pareto dominance concepts, the approach generates a model composed by rules with specific properties. These rules can be used as an unordered classifier, and because of this, they are more intuitive and comprehensible. Two experiments were accomplished, considering, respectively, fault-proneness of classes and methods. The results show interesting relationships between the studied metrics and fault prediction. In addition to this, the performance of the introduced MOPSO approach is compared with other ML algorithms by using several measures including the area under the ROC curve, which is a relevant criterion to deal with unbalanced data.     

基于多目标决策的维修分队抽组优化模型

针对解决从多个维修分队中派出最佳维修分队进行产品维修的问题，从运筹学的角度出发，抽象提取出影响抽组优化的要素，研究并提出了利用多目标决策理论解决维修分队抽组优化问题的方法，给出了相应的抽组优化模型，阐述了具体演算过程。