Pure Genetic Algorithm Research Articles

Application of hybrid evolutionary algorithms to low exhaust emission diesel engine design

A hybrid evolutionary algorithm, consisting of a genetic algorithm (GA) and particle swarm optimization (PSO), is proposed. Generally, GAs maintain diverse solutions of good quality in multi-objective problems, while PSO shows fast convergence to the optimum solution. By coupling these algorithms, GA will compensate for the low diversity of PSO, while PSO will compensate for the high computational costs of GA. The hybrid algorithm was validated using standard test functions. The results showed that the hybrid algorithm has better performance than either a pure GA or pure PSO. The method was applied to an engineering design problem—the geometry of diesel engine combustion chamber reducing exhaust emissions such as NOx, soot and CO was optimized. The results demonstrated the usefulness of the present method to this engineering design problem. To identify the relation between exhaust emissions and combustion chamber geometry, data mining was performed with a self-organising map (SOM). The results indicate that the volume near the lower central part of the combustion chamber has a large effect on exhaust emissions and the optimum chamber geometry will vary depending on fuel injection angle.

A GA-based Multi-Objective Decision Making for Optimal Vehicle Transportation

In this study, a genetic algorithm is applied to obtain the best combination of transportation parameters for vehicle dispatching. The searching mechanism based on genetic algorithm can find several feasible solutions of dispatching parameters to proceed with transportation plan within constrained conditions. Besides, the concept of fuzzy due time is applied to replace that of time window so as to meet customers’ preferences and demands much better. A fuzzy vehicle routing and scheduling problem (FVRSP) is formulated with five attributes: space utility, service satisfaction, waiting time, delay time, and transportation distance and proposed to solve it with a pure genetic algorithm method. In addition, the system can simultaneously calculate the residual loading capacity of weight and volume of each vehicle in order to provide the dispatcher with options to tune the dispatching operation. With the help of this system of acquiring the optimal solution to vehicle transportation, the promotion of the efficiency of transportation can thus be achieved.

PARAMETRIC IDENTIFICATION OF NONLINEAR DYNAMIC SYSTEMS USING COMBINED LEVENBERG–MARQUARDT AND GENETIC ALGORITHM

This technical note presents the parametric identification of multi-degree-of-freedom nonlinear dynamic systems in the time domain using a combination of Levenberg–Marquardt (LM) method and Genetic Algorithm (GA). Here the crucial initial values to the LM algorithm are supplied by GA with a small population size. Two nonlinear systems are studied, the complex one having two nonlinear spring-damper pairs. The springs have cubic nonlinearity (Duffing oscillator) and dampers have quadratic nonlinearity. The effects of noise in the acceleration measurements and sensitivity analysis are also studied. The performance of combined GA and LM method is compared with pure LM and pure GA in terms of solution time, accuracy and number of iterations, and convergence and great improvement is observed. This method is found to be suitable for the identification of complex nonlinear systems, where the repeated solution of the numerically difficult equations over many generations requires enormous computational effort.

Structural topology and element sizing design optimisation of tall steel frameworks using a hybrid OC–GA method

This paper presents a hybrid optimisation method in which a local search operator based on a rigorously derived optimality criteria (OC) technique is embedded in the framework of a genetic algorithm (GA). The GA framework is particularly useful in the global exploration for optimal topologies, while the OC technique serves as a local search operator for efficient element sizing optimisation of given topologies. The hybrid OC–GA method was developed to strike a balance between the exploration of global search algorithms and the exploitation of efficient local search methods so as to make the hybrid method suitable for optimising tall building structures involving a large number of structural elements. The applicability and efficiency of the hybrid OC–GA method were tested with two 40-storey steel frameworks. The results show that the hybrid method can generate superior designs to pure GA while exhibiting rapid and smooth convergence, suggesting its great potential for optimising both structural form and element size of practical tall building structures.

Near optimal guidance law for descent to a point using inverse problem approach

An explicit guidance law that maximizes terminal velocity is developed for a reentry vehicle to a fixed target. Motion is constrained to an optimal, three-dimensional Bezier curve. Acceleration commands are derived by solving an inverse problem related to Bezier parameters. An optimal Bezier curve is determined by solving a real-coded genetic algorithm. For online trajectory generation, optimal trajectory is approximated by fixing the second control point of the Bezier curve. The approximated trajectory is compared with the pure proportional navigation, genetic algorithm and direct transcription's solutions. The near optimal terminal velocity solution compares very well with these solutions. The approach robustness is examined by Monte Carlo simulation.

Discrete channel modelling based on genetic algorithm and simulated annealing for training hidden Markov model

Hidden Markov models (HMMs) have been used to model burst error sources of wireless channels. This paper proposes a hybrid method of using genetic algorithm (GA) and simulated annealing (SA) to train HMM for discrete channel modelling. The proposed method is compared with pure GA, and experimental results show that the HMMs trained by the hybrid method can better describe the error sequences due to SA’s ability of facilitating hill-climbing at the later stage of the search. The burst error statistics of the HMMs trained by the proposed method and the corresponding error sequences are also presented to validate the proposed method.

Heuristic solutions for general concave minimum cost network flow problems

AbstractWe address the single‐source uncapacitated minimum cost network flow problem with general concave cost functions. Exact methods to solve this class of problems in their full generality are only able to address small to medium size instances, since this class of problems is known to be NP‐Hard. Therefore, approximate methods are more suitable. In this work, we present a hybrid approach combining a genetic algorithm with a local search. Randomly generated test problems have been used to test the computational performance of the algorithm. The results obtained for these test problems are compared to optimal solutions obtained by a dynamic programming method for the smaller problem instances and to upper bounds obtained by a local search method for the larger problem instances. From the results reported it can be shown that the hybrid methodology improves upon previous approaches in terms of efficiency and also on the pure genetic algorithm, i.e., without using the local search procedure. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(1), 67–76 2007

Hybrid multi-objective shape design optimization using Taguchi’s method and genetic algorithm

This research is based on a new hybrid approach, which deals with the improvement of shape optimization process. The objective is to contribute to the development of more efficient shape optimization approaches in an integrated optimal topology and shape optimization area with the help of genetic algorithms and robustness issues. An improved genetic algorithm is introduced to solve multi-objective shape design optimization problems. The specific issue of this research is to overcome the limitations caused by larger population of solutions in the pure multi-objective genetic algorithm. The combination of genetic algorithm with robust parameter design through a smaller population of individuals results in a solution that leads to better parameter values for design optimization problems. The effectiveness of the proposed hybrid approach is illustrated and evaluated with test problems taken from literature. It is also shown that the proposed approach can be used as first stage in other multi-objective genetic algorithms to enhance the performance of genetic algorithms. Finally, the shape optimization of a vehicle component is presented to illustrate how the present approach can be applied for solving multi-objective shape design optimization problems.

A hybrid genetic algorithm for the re-entrant flow-shop scheduling problem

This study considers the production environment of the re-entrant flow-shop (RFS). In a RFS, all jobs have the same routing over the machines of the shop and the same sequence is traversed several times to complete the jobs. The aim of this study is to minimize makespan by using the genetic algorithm (GA) to move from local optimal solution to near optimal solution for RFS scheduling problems. In addition, hybrid genetic algorithms (HGA) are proposed to enhance the performance of pure GA. The HGA is compared to the optimal solutions generated by the integer programming technique, and to the near optimal solutions generated by pure GA and the non-delay schedule generation procedure. Computational experiments are performed to illustrate the effectiveness and efficiency of the proposed HGA algorithm.

A hybrid genetic—instance based learning algorithm for CE-QUAL-W2 calibration

This paper presents a calibration model for CE-QUAL-W2. CE-QUAL-W2 is a two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model for surface water bodies, modeling eutrophication processes such as temperature–nutrient–algae–dissolved oxygen–organic matter and sediment relationships. The proposed methodology is a combination of a ‘hurdle-race’ and a hybrid Genetic- k-Nearest Neighbor algorithm (GA-kNN). The ‘hurdle race’ is formulated for accepting–rejecting a proposed set of parameters during a CE-QUAL-W2 simulation; the k-Nearest Neighbor algorithm (kNN)—for approximating the objective function response surface; and the Genetic Algorithm (GA)—for linking both. The proposed methodology overcomes the high, non-applicable, computational efforts required if a conventional calibration search technique was used, while retaining the quality of the final calibration results. Base runs and sensitivity analysis are demonstrated on two example applications: a synthetic hypothetical example calibrated for temperature, serving for tuning the GA-kNN parameters; and the Lower Columbia Slough case study in Oregon US calibrated for temperature and dissolved oxygen. The GA-kNN algorithm was found to be robust and reliable, producing similar results to those of a pure GA, while reducing running times and computational efforts significantly, and adding additional insights and flexibilities to the calibration process.

Operational Optimization of Water Distribution Systems Using a Hybrid Genetic Algorithm

Genetic algorithm (GA) optimization is well suited for optimizing the operation of water distribution systems, especially large and complex systems. GAs have good initial convergence characteristics, but slow down considerably once the region of optimal solution has been identified. In this study the efficiency of GA operational optimization was improved through a hybrid method which combines the GA method with a hillclimber search strategy. Hillclimber strategies complement GAs by being efficient in finding a local optimum. Two hillclimber strategies, the Hooke and Jeeves and Fibonacci methods, were investigated. The hybrid method proved to be superior to the pure GA in finding a good solution quickly, both when applied to a test problem and to a large existing water distribution system.

Hybrid Strategy for Parameter Estimation and PID Tuning

Parameter estimation and PID timing are two crucial issues in control engineering. Classical methods either require some prior information or depend on some rules, especially they are short of generality and their performances are not satisfied in many engineering fields. Although genetic algorithm and simulated annealing approaches have gained much attention and applications during the past decades, it may cause the premature convergence of genetic algorithm and prohibitive time-consumption required for simulated annealing if executing them alone. In this paper, reasonably combining the parallel structure of genetic algorithm with the controllable jumping property of simulated annealing, a class of effective and general hybrid optimization strategy is proposed for parameter estimation and PID tuning. The proposed strategy is easy to be understood and implemented, and only a little pre-needed information is required. Numerical simulation results demonstrate that the hybrid strategy is of effectiveness, robustness on initial states, and adaptability on models or plants, and comparisons show that the hybrid strategy can achieve performances greatly better than those of pure genetic algorithm and classical methods.

Neural-network-assisted genetic algorithm applied to silicon clusters

Recently, a new optimization procedure that combines the power of artificial neural-networks with the versatility of the genetic algorithm (GA) was introduced. This method, called neural-network-assisted genetic algorithm (NAGA), uses a neural network to restrict the search space and it is expected to speed up the solution of global optimization problems if some previous information is available. In this paper, we have tested NAGA to determine the ground-state geometry of ${\mathrm{Si}}_{n}$ $(10l~nl~15)$ according to a tight-binding total-energy method. Our results indicate that NAGA was able to find the desired global minimum of the potential energy for all the test cases and it was at least ten times faster than pure genetic algorithm.

Study of the Ground-State Geometry of Silicon Clusters Using Artificial Neural Networks

Theoretical determination of the ground-state geometry of Si clusters is a difficult task. As the number of local minima grows exponentially with the number of atoms, to find the global minimum is a real challenge. One may start the search procedure from a random distribution of atoms but it is probably wiser to make use of any available information to restrict the search space. Here, we introduce a new approach, the Assisted Genetic Optimization (AGO) that couples an Artificial Neural Network (ANN) to a Genetic Algorithm (GA). Using available information on small Silicon clusters, we trained an ANN to predict good starting points (initial population) for the GA. AGO is applied to Si10 and Si20 and compared to pure GA. Our results indicate: i) AGO is, at least, 5 times faster than pure GA in our test case; ii) ANN training can be made very fast and successfully plays the role of an experienced investigator; iii) AGO can easily be adapted to other optimization problems.

Estudo do estado fundamental de aglomerados de silício via redes neurais

We introduce a global optimization method based on the cooperation between an Artificial Neural Net (ANN) and Genetic Algorithm (GA). We have used ANN to select the initial population for the GA. We have tested the new method to predict the ground-state geometry of silicon clusters. We have described the clusters as a piling of plane structures. We have trained three ANN architectures and compared their results with those of pure GA. ANN strongly reduces the total computational time. For Si10, it gained a factor of 5 in search speed. This method can be easily extended to other optimization problems.

A genetic algorithm for the vehicle routing problem

This study considers the application of a genetic algorithm (GA) to the basic vehicle routing problem (VRP), in which customers of known demand are supplied from a single depot. Vehicles are subject to a weight limit and, in some cases, to a limit on the distance travelled. Only one vehicle is allowed to supply each customer. The best known results for benchmark VRPs have been obtained using tabu search or simulated annealing. GAs have seen widespread application to various combinatorial optimisation problems, including certain types of vehicle routing problem, especially where time windows are included. However, they do not appear to have made a great impact so far on the VRP as described here. In this paper, computational results are given for the pure GA which is put forward. Further results are given using a hybrid of this GA with neighbourhood search methods, showing that this approach is competitive with tabu search and simulated annealing in terms of solution time and quality. Scope and purpose The basic vehicle routing problem (VRP) consists of a number of customers, each requiring a specified weight of goods to be delivered. Vehicles despatched from a single depot must deliver the goods required, then return to the depot. Each vehicle can carry a limited weight and may also be restricted in the total distance it can travel. Only one vehicle is allowed to visit each customer. The problem is to find a set of delivery routes satisfying these requirements and giving minimal total cost. In practice, this is often taken to be equivalent to minimising the total distance travelled, or to minimising the number of vehicles used and then minimising total distance for this number of vehicles. Most published research for the VRP has focused on the development of heuristics. Although the development of modern heuristics has led to considerable progress, the quest for improved performance continues. Genetic algorithms (GAs) have been used to tackle many combinatorial problems, including certain types of vehicle routing problem. However, it appears that GAs have not yet made a great impact on the VRP as described here. This paper describes a GA that we have developed for the VRP, showing that this approach can be competitive with other modern heuristic techniques in terms of solution time and quality.

A hybrid genetic algorithm for the batch sequencing problem on identical parallel machines

The batch sequencing problem (BSP) has been the focus of much research thanks to its practical applicability and NP-hard nature. This study aims to solve an extension of the problem from single machine case to parallel machine case. A dispatching rule called the EDD (Earliest Due Date)-Greedy heuristic and a pure genetic algorithm (GA) are proposed, and then combine them through an insertion method called the Gene Bank Strategy. Several test cases of up to 12 machines and 60 jobs are randomly generated and solved. Those experiments show that the introduced hybrid GA can provide far better results than its two component algorithms that can also independently solve the problem.

A memetic algorithm for the total tardiness single machine scheduling problem

In this paper, a new memetic algorithm (MA) for the total tardiness single machine scheduling (SMS) problem with due dates and sequence-dependent setup times is proposed. The main contributions with respect to the implementation of the hybrid population approach are a hierarchically structured population conceived as a ternary tree and the evaluation of three recombination operators. Concerning the local improvement procedure, several neighborhood reduction schemes are developed and proved to be effective when compared to the complete neighborhood. Results of computational experiments are reported for a set of randomly generated test problems. The memetic approach and a pure genetic algorithm (GA) version are compared with a multiple start algorithm that employs the all-pairs neighborhood as well as two constructive heuristics.

Baldwinian learning utilizing genetic and heuristic algorithms for logic synthesis and minimization of incompletely specified data with Generalized Reed–Muller (AND–EXOR) forms

Abstract This research applies a new heuristic combined with a genetic algorithm (GA) to the task of logic minimization for incompletely specified data, with both single and multi-outputs, using the Generalized Reed–Muller (GRM) equation form. The GRM equation type is a canonical expression of the Exclusive-Or Sum-of-Products (ESOPs) type, in which for every subset of input variables there exists not more than one term with arbitrary polarities of all variables. This AND–EXOR implementation has been shown to be economical, generally requiring fewer gates and connections than that of AND–OR logic. GRM logic is also highly testable, making it desirable for FPGA designs. The minimization results of this new algorithm tested on a number of binary benchmarks are given. This minimization algorithm utilizes a GA with a two-level fitness calculation, which combines human-designed heuristics with the evolutionary process, employing Baldwinian learning. In this algorithm, first a pure GA creates certain constraints for the selection of chromosomes, creating only genotypes (polarity vectors). The phenotypes (GRMs) are then learned in the environment and contribute to the GA fitness (which is the total number of terms of the best GRM for each output), providing indirect feedback as to the quality of the genotypes (polarity vectors) but the genotype chromosomes (polarity vectors) remain unchanged. In this process, the improvement in genotype chromosomes (polarity vectors) is the product of the evolutionary processes from the GA only. The environmental learning is achieved using a human-designed GRM minimization heuristic. As much previous research has presented the merit of AND–EXOR logic for its high density and testability, this research is the first application of the GRM (a canonical AND–EXOR form) to the minimization of incompletely specified data.

Programação da produção em sistemas flow shop utilizando um método heurístico híbrido algoritmo genético-simulated annealing

Este artigo trata do problema de programação de tarefas flow shop permutacional. Diversos métodos heurísticos têm sido propostos para tal problema, sendo que um dos tipos de método consiste em melhorar soluções iniciais a partir de procedimentos de busca no espaço de soluções, tais como Algoritmo Genético (AG) e Simulated Annealing (SA). Uma idéia interessante que tem despertado gradativa atenção refere-se ao desenvolvimento de métodos heurísticos híbridos utilizando Algoritmo Genético e Simulated Annealing. Assim, o objetivo é combinar as técnicas de tal forma que o procedimento resultante seja mais eficaz do que qualquer um dos seus componentes isoladamente. Neste artigo é apresentado um método heurístico híbrido Algoritmo Genético-Simulated Annealing para minimizar a duração total da programação flow shop permutacional. Com o propósito de avaliar a eficácia da hibridização, o método híbrido é comparado com métodos puros AG e SA. Os resultados obtidos a partir de uma experimentação computacional são apresentados.