多项目资源均衡优化的免疫遗传算法研究

针对多项目管理“工期固定-资源均衡”问题特点,设计免疫遗传算法对该类问题的求解。免疫遗传算法是模仿生物免疫系统的一种启发式算法,其在免疫算子中加入遗传算子,改进了遗传算法收敛方向无法控制易早熟的缺陷,使算法具有更好的全局搜索能力和记忆功能。最后,结合算例对算法进行验证和分析。     

A compact genetic algorithm for the network coding based resource minimization problem

In network coding based data transmission, intermediate nodes in the network are allowed to perform mathematical operations to recombine (code) data packets received from different incoming links. Such coding operations incur additional computational overhead and consume public resources such as buffering and computational resource within the network. Therefore, the amount of coding operations is expected to be minimized so that more public resources are left for other network applications.     

基于免疫遗传算法的海工多项目资源均衡研究

为使海工项目建造过程中的资源利用更加均衡,建立了海工多项目资源均衡问题模型,并提出了一种基于免疫遗传算法的求解方法.该方法借鉴生物免疫系统原理,对遗传算法进行改进,提出了基于抗体浓度的群体更新策略,以保持抗体种群多样性,克服遗传算法容易早熟及局部寻优能力较差的缺陷;并根据问题模型的启发式信息,将问题约束条件分为两种不同类型,进行分别处理.通过具体算例表明了算法的可行性和有效性.     

A random key based genetic algorithm for the resource constrained project scheduling problem

This paper presents a genetic algorithm for the Resource Constrained Project Scheduling Problem (RCPSP). The chromosome representation of the problem is based on random keys. The schedule is constructed using a heuristic priority rule in which the priorities of the activities are defined by the genetic algorithm. The heuristic generates parameterized active schedules. The approach was tested on a set of standard problems taken from the literature and compared with other approaches. The computational results validate the effectiveness of the proposed algorithm.     

A robust dynamic niching genetic algorithm with niche migration for automatic clustering problem

In this paper, a genetic clustering algorithm based on dynamic niching with niche migration (DNNM-clustering) is proposed. It is an effective and robust approach to clustering on the basis of a similarity function relating to the approximate density shape estimation. In the new algorithm, a dynamic identification of the niches with niche migration is performed at each generation to automatically evolve the optimal number of clusters as well as the cluster centers of the data set without invoking cluster validity functions. The niches can move slowly under the migration operator which makes the dynamic niching method independent of the radius of the niches. Compared to other existing methods, the proposed clustering method exhibits the following robust characteristics: (1) robust to the initialization, (2) robust to clusters volumes (ability to detect different volumes of clusters), and (3) robust to noise. Moreover, it is free of the radius of the niches and does not need to pre-specify the number of clusters. Several data sets with widely varying characteristics are used to demonstrate its superiority. An application of the DNNM-clustering algorithm in unsupervised classification of the multispectral remote sensing image is also provided.     

工序可间断的资源均衡分析

针对网络计划资源均衡问题,提出了一种新型的工序可间断的资源均衡模型,并在模型中引入一些工序间断率、间断延期率等无量纲变量来处理工序可间断的情况。这些变量使得模型中各工序间的时间约束关系在求解过程中能自动得到满足,从而避免不可行解的出现。该模型还兼容了不可间断资源均衡模型的功能,并可以处理特殊工序不可间断的要求。通过采用遗传算法对本文的模型进行求解,验证了模型的有效性。     

A genetic algorithm for the project assignment problem

In this paper we present a genetic algorithm as an aid for project assignment. The assignment problem illustrated concerns the allocation of projects to students. Students have to choose from a list of possible projects, indicating their preferred choices in advance. Inevitably, some of the more popular projects become ‘over-subscribed’ and assignment becomes a complex problem. The developed algorithm has compared well to an optimal integer programming approach. One clear advantage of the genetic algorithm is that, by its very nature, we are able to produce a number of feasible project assignments, thus facilitating discussion on the merits of various allocations and supporting multi-objective decision making.     

A GPU-based genetic algorithm for the p-median problem

The p-median problem is a well-known NP-hard problem. Many heuristics have been proposed in the literature for this problem. In this paper, we exploit a GPGPU parallel computing platform to present a new genetic algorithm implemented in CUDA and based on a pseudo-Boolean formulation of the p-median problem. We have tested the effectiveness of our algorithm using a Tesla K40 (2880 CUDA cores) on 290 different benchmark instances obtained from OR-Library, discrete location problems benchmark library, and benchmarks introduced in recent publications. The algorithm succeeded in finding optimal solutions for all instances except for two OR-library instances, namely pmed 30 and pmed 40, where better than 99.9% approximations were obtained.     

基于遗传算法求解三维匹配的资源分配问题

针对非正交多址接入(NOMA)技术的两层异构网络(HetNets)的资源配置,因用户、基站和子信道三维匹配属于NP难题,多分解为二维匹配求解,为此提出一种改进的遗传算法(GA)求解用户的多维匹配。为满足系统总容量最大并降低时间复杂度,将遗传算法的编码方式设计为一种多维映射过程;为防止陷入局部最优并提高全局搜索能力,对选择算子进行确定性和随机性的结合。实验结果表明,该算法相对于贪婪算法和双边匹配算法,具有收敛速度快和全局性更好等优点。     

A parameter-tuned genetic algorithm for the resource investment problem with discounted cash flows and generalized precedence relations

A resource investment problem with discounted cash flows (RIPDCF) is a project-scheduling problem in which (a) the availability levels of the resources are considered decision variables and (b) the goal is to find a schedule such that the net present value of the project cash flows optimizes. In this paper, the RIPDCF in which the activities are subject to generalized precedence relations is first modeled. Then, a genetic algorithm (GA) is proposed to solve this model. In addition, design of experiments and response surface methodology are employed to both tune the GA parameters and to evaluate the performance of the proposed method in 240 test problems. The results of the performance analysis show that the efficiency of the proposed GA method is relatively well.     

A genetic algorithm approach for the cutting stock problem

In this paper, a genetic algorithm approach is developed for solving the rectangular cutting stock problem. The performance measure is the minimization of the waste. Simulation results obtained from the genetic algorithm-based approach are compared with one heuristic based on partial enumeration of all feasible patterns, and another heuristic based on a genetic neuro-nesting approach. Some test problems taken from the literature were used for the experimentation. Finally, the genetic algorithm approach was applied to test problems generated randomly. The simulation results of the proposed approach in terms of solution quality are encouraging when compared to the partial enumeration-based heuristic and the genetic neuro-nesting approach.     

A genetic algorithm for the minimum generating set problem

Given a set of positive integers S, the minimum generating set problem consists in finding a set of positive integers T with a minimum cardinality such that every element of S can be expressed as the sum of a subset of elements in T. It constitutes a natural problem in combinatorial number theory and is related to some real-world problems, such as planning radiation therapies.We present a new formulation to this problem (based on the terminology for the multiple knapsack problem) that is used to design an evolutionary approach whose performance is driven by three search strategies; a novel random greedy heuristic scheme that is employed to construct initial solutions, a specialized crossover operator inspired by real-parameter crossovers and a restart mechanism that is incorporated to avoid premature convergence. Computational results for problem instances involving up to 100,000 elements show that our innovative genetic algorithm is a very attractive alternative to the existing approaches.     

A genetic algorithm for solving the two-dimensional assortment problem

Assortment problems arise in various industries such as the steel, paper, textiles and transportation industries. Two-dimensional assortment problems involve finding the best way of placing a set of rectangles within another rectangle whose area is minimized. Such problems are nonlinear and combinatorial. Current mixed integer programming models give optimal solutions, but the computation times are unacceptable. This study proposes a genetic algorithm that incorporates a novel random packing process and an encoding scheme for solving the assortment problem. Numerical examples indicate that the proposed genetic algorithm is considerably more efficient and effective than a fast integer programming model. Errors with respect to the optimal solutions are low such that numerous practical industrial cutting problems can be solved efficiently using the proposed method.     

A genetic cluster algorithm for the machine-component grouping problem

This research presents the usage of a genetic algorithm for the clustering of parts and machines. A detailed analysis is shown comparing GCA results with single link cluster analysis, rank order clustering, and the direct clustering algorithm. GCA was also compared with several additional cell formation heuristics described in the recent literature, including GRAPHICS, MODROC, and a cost-based heuristic. Results showed that the GCA was far superior over single link cluster analysis and provided equivalent results to those of the direct clustering algorithm and rank order clustering. GCA was also found to provide superior results to the other heuristics. The discussion explains these findings by illustrating the inflexibility of traditional cell formation heuristics in the selection of final machine-component groupings.     

A memetic genetic algorithm for the vertex p-center problem

Abstract The p-center problem is one of choosing p facilities from a set of candidates to satisfy the demands of n clients in order to minimize the maximum cost between a client and the facility to which it is assigned. In this article, PBS, a population based meta-heuristic for the p-center problem, is described. PBS is a genetic algorithm based meta-heuristic that uses phenotype crossover and directed mutation operators to generate new starting points for a local search. For larger p-center instances, PBS is able to effectively utilize a number of computer processors. It is shown empirically that PBS has comparable performance to state-of-the-art exact and approximate algorithms for a range of p-center benchmark instances.     

多智能体布谷鸟算法的网络计划资源均衡优化

网络计划资源均衡属于组合优化问题,为了能快速有效地求解此类问题,提出了一种多智能体布谷鸟算法。针对标准布谷鸟算法缺乏信息共享的缺陷,将多智能体系统引入布谷鸟算法中。多智能体的邻域竞争合作算子实现智能体间信息的交流,加快算法收敛速度;变异算子扩大搜索范围增加种群多样性;自学习算子提高局部寻优的能力;布谷鸟算法的Levy飞行进化机制能有效地跳出局部最优实现全局收敛。实例仿真结果证实了,与其他算法相比多智能体布谷鸟算法能更有效地求解网络计划资源均衡优化问题。     

A multi-population genetic algorithm for robust and fast ellipse detection

This paper discusses a novel and effective technique for extracting multiple ellipses from an image, using a genetic algorithm with multiple populations (MPGA). MPGA evolves a number of subpopulations in parallel, each of which is clustered around an actual or perceived ellipse in the target image. The technique uses both evolution and clustering to direct the search for ellipses—full or partial. MPGA is explained in detail, and compared with both the widely used randomized Hough transform (RHT) and the sharing genetic algorithm (SGA). In thorough and fair experimental tests, using both synthetic and real-world images, MPGA exhibits solid advantages over RHT and SGA in terms of accuracy of recognition—even in the presence of noise or/and multiple imperfect ellipses in an image—and speed of computation.     

A genetic algorithm for maximum-weighted tree matching problem

In hierarchal organizations, for assigning tasks to the divisions of the organization some constraints must be satisfied. This article investigates one such problem in which there are k different tasks to be accomplished and each division’s performance on each task may be different and represented by a scalar value. In this article we formally introduce this real life decision problem, named as Maximum-Weighted Tree Matching Problem, and propose a genetic algorithm solution to it, and give some experimental results.     

A multi-objective genetic algorithm for the hot mix asphalt problem

Neural Computing and Applications - It is desirable for the work done in any construction process to be both cost-effective and durable. A thorough consideration of the matter reveals that the...     

A new genetic algorithm for the asymmetric traveling salesman problem

The asymmetric traveling salesman problem (ATSP) is one of the most important combinatorial optimization problems. It allows us to solve, either directly or through a transformation, many real-world problems. We present in this paper a new competitive genetic algorithm to solve this problem. This algorithm has been checked on a set of 153 benchmark instances with known optimal solution and it outperforms the results obtained with previous ATSP heuristic methods.