共查询到20条相似文献，搜索用时 233 毫秒
1.
１ＩｎｔｒｏｄｕｃｔｉｏｎＧｅｎｅｔｉｃａｌｇｏｒｉｔｈｍｓ（ＧＡｓ）ｗｅｒｅｐｒｏｐｏｓｅｄｔｏｓｏｌｖｅｐｌａｎｎｉｎｇ,ｓｃｈｅｄｕｌｉｎｇ,ｏｒｏｐｔｉｍｉｚａｔｉｏｎｐｒｏｂｌｅｍｓｉｎ１９７０ｓ．ＧＡｓｓｉｍｕｌａｔｅｎａｔｕｒａｌｅｖｏ... 相似文献
2.
This paper presents a new genetic algorithm for the resource-constrained project scheduling problem(RCPSP).The algorithm employs a standardized random key(SRK) vector representation with an additional gene that determines whether the serial or parallel schedule generation scheme(SGS) is to be used as the decoding procedure.The iterative forward-backward improvement as the local search procedure is applied upon all generated solutions to schedule the project three times and obtain an SRK vector,which is rese... 相似文献
3.
WANG Fang CHENG Shui-yuan LI Ming-jun FAN Qing CHEN Dong-sheng WANG Hai-yan ZHANG Wei 《重庆大学学报(英文版)》2010,9(3):117-123
We developed and tested an improved neural network to predict the average concentration of PM10 （particulate matter with diameter smaller than 10 μm） several hours in advance in summer in Beijing. A genetic algorithm optimization procedure for optimizing initial weights and thresholds of the neural network was also evaluated. This research was based upon the PM10 data from seven monitoring sites in Beijing urban region and meteorological observation data, which were recorded every 3 h during summer of 2002. Two neural network models were developed. Model I was built for predicting PM10 concentrations 3 h in advance while Model II for one day in advance. The predictions of both models were found to be consistent with observations. Percent errors in forecasting the numerical value were about 20%. This brings us to the conclusion that short-term fluctuations of PM10 concentrations in Beijing urban region in summer are to a large extent driven by meteorological conditions. Moreover, the predicted results of Model II were compared with the ones provided by the Models-3 Community Multiscale Air Quality （CMAQ） modeling system. The mean relative errors of both models were 0.21 and 0.26, respectively. The performance of the neural network model was similar to numerical models, when applied to short-time prediction of PM10 concentration. 相似文献
4.
IntroductionTheHitchcock’sTransportationProblem(HTP)canbeformulatedasaclassiclinearprogrammingprobleminwhichthesetofconstraintsisofaspecialstructure[1,2].TheHTPisapracticaltransportationprobleminproductiondistributionsector.Alotofpracticaltrans-portationandassignmentproblems,suchastheminimumcostroadnetworktrafficflowproblemwithsolidchargeinlogistics,canbeformulatedinthisway,anditisclearlythattheHTPmaybehasmorethanoneoptimalsolution.Itisveryimportantforadecision-makertoselectafavorableone… 相似文献
5.
This paper dealt with composite scheduling problems which combine manufacturing scheduling problems and/or transportation routing problems.Two scheduling models were formulated as the elements of the composite scheduling model,and the composite model was formulated composing these models with indispensable additional constraints.A hybrid genetic algorithm was developed to solve the composite scheduling problems.An improved representation based on random keys was developed to search permutation space.A genetic algorithm based dynamic programming approach was applied to select resource.The proposed technique and a previous technique are compared by three types of problems.All results indicate that the proposed technique is superior to the previous one. 相似文献
6.
Both fuzzy temporal constraint and flexible resource constraint are considered in project scheduling. Inorder to obtain an optimal schedule, we propose a genetic algorithm integrated with concepts on fuzzy set theory aswell as specialized coding and decoding mechanism. An example demonstrates that the proposed approach can assistthe project managers to obtain the optimal schedule effectively and make the correct decision on skill training before aproject begins. 相似文献
7.
YU Bin TIAN Feng-chun HE Qing-hu RAN Jian LV Bo HONG Xin LIU Tao BI Yu-tian 《重庆大学学报(英文版)》2016,15(4):127-138
In this paper, a wavelet packet feature selection method for lung sounds based on optimization is proposed to obtain the best feature set which maximizes the differences between normal lung sounds and abnormal lung sounds (sounds with wheezes or rales). The proposed method includes two main steps: Firstly, the wavelet packet transform (WPT) is used to extract the original features of lung sounds; then the genetic algorithm (GA) is used to select the best feature set. The obtained optimal feature set is sent to four different classifiers to evaluate the performance of the proposed method. Experimental results show that the feature set obtained by the proposed method provides a higher classification accuracy of 94.6% in comparison with the best wavelet packet basis approach and multi-scale principal component analysis (PCA) approach. Meanwhile, the proposed method has effective generalization performance and can obtain the best feature set without priori knowledge of lung sounds. 相似文献
8.
The Ethernet passive optical network (EPON) is the next generation of broad-band network technique. A crucial issue in EPONs is the sharing of uplink bandwidth among optical network units (ONUs). This article provides a novel dynamic bandwidth allocation algorithm, i.e. threshold dynamic bandwidth allocation (TDBA), which is based on adaptive threshold, to increase resource utilization. The algorithm uses ONU data-transmitting rate to adjust optical line terminal (OLT) receiving data threshold from an ONU. Simulation results show that this algorithm can decrease average packet delay and increase network throughput in a 10G EPON system. 相似文献
9.
计算机及其网络的发展在改变着人们的经济模式和文化观念,同时对英语学习也产生了巨大的影响。计算机辅助语言学习已成为或将要成为一种新的英语学习模式。一、计算机及其网络在语言学习上的应用计算机辅助教学 CAI(Computer Aided Instruction)是计算机非常重要的应用领域之一,其中计算机辅助语言学习 CALL(Computer Assisted Language 相似文献
10.
计算机及其网络的发展在改变着人们的经济模式和文化观念,同时对英语教学也产生了巨大的影响,任何一种传统的英语教学方法都是无法同它相比的.过去的英语教学,除了教师在课堂上使用授语外,虽也借助其它手段,如图片、录音带、录象带等,但效果都不理想,而借助计算机(软件)及其网络进行教学则可大大弥补其不足.计算机辅助语言学习已成为或将要成 相似文献
11.
Hybrid discrete particle swarm optimization algorithm for capacitated vehicle routing problem 总被引：11，自引：0，他引：11
CHEN Ai-ling YANG Gen-ke WU Zhi-ming 《浙江大学学报(A卷英文版)》2006,7(4):607-614
INTRODUCTION The vehicle routing problem (VRP), which was first introduced by Dantzig and Ramser (1959), is a well-known combinatorial optimization problem in the field of service operations management and logis- tics. The capacitated vehicle routing problem (CVRP) is an NP-hard problem for simultaneously determining the routes for several vehicles from a central depot to a set of customers, and then return to the depot without exceeding the capacity constraints of each vehicle. In pr… 相似文献
12.
The permutation flowshop scheduling problem (PFSP) is one of the most well-known and well-studied production scheduling problems with strong industrial background. This paper presents a new hybrid optimization algorithm which combines the strong global search ability of artificial immune system (AIS) with a strong local search ability of extremal optimization (EO) algorithm. The proposed algorithm is applied to a set of benchmark problems with a makespan criterion. Performance of the algorithm is evaluated. Comparison results indicate that this new method is an effective and competitive approach to the PFSP. 相似文献
13.
针对信赖域算法求解非线性优化无法找到局部最优解的问题,提出一种基于模拟退火粒子群的信赖域算法.该算法先利用模拟退火改进粒子群的后期寻优能力,克服＂早熟收敛＂,再与信赖域算法结合,有效求解无约束化信赖域子问题。数值实验表明,新算法具有良好的全局寻优能力和收敛能力,计算精度高。 相似文献
14.
为克服粒子群算法在处理复杂高维问题时易陷入局部最优及寻优精度低等缺陷,提出一种融合 Rosenbrock 搜索法的混合粒子群算法。首先,利用 Tent 混沌序列进行种群初始化;其次,采用去速度项的简化粒子群公式提高收敛速度并对个体极值加入扰动,增强粒子种群多样性;最后,当全局最优个体更新停滞时,利用Rosenbrock 搜索法对全局最优个体进行局部搜索,提高解的精度。利用 8 个常用基准测试函数分别对 30 维和50 维问题进行实验,证实该算法可寻到病态函数 Rosenbrock 全局最优值,且比其它 7 个函数的寻优精度提高10-2 数量级。实验证明该算法收敛速度快,解的精度高,全局搜索能力强,寻优能力明显提高。 相似文献
15.
An efficient hybrid evolutionary optimization algorithm based on PSO and SA for clustering 总被引：4，自引：0，他引：4
The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the K- means algorithm depends highly on initial cluster centers and converges to local minima. This paper proposes a hybrid evolutionary programming based clustering algorithm, called PSO-SA, by combining particle swarm optimization （PSO） and simulated annealing （SA）. The basic idea is to search around the global solution by SA and to increase the information exchange among particles using a mutation operator to escape local optima. Three datasets, Iris, Wisconsin Breast Cancer, and Ripley＇s Glass, have been considered to show the effectiveness of the proposed clustering algorithm in providing optimal clusters. The simulation results show that the PSO-SA clustering algorithm not only has a better response but also converges more quickly than the K-means, PSO, and SA algorithms. 相似文献
16.
提出了一种解决无线传感器网络覆盖问题的能量有效性启发式机制.该机制在节能的前提下,实现了对目标监控区域的完全覆盖,且覆盖精度与目标的重要性级别成正比关系.机制的实现运用了蚁群优化算法,算法的设计过程采用了新颖的启发式因子构造方法和基于评价函数的全局信息素更新规则,由此,人工蚂蚁被赋予了对目标监控区域的覆盖状况和对传感器网络区域能量状况的自适应感知能力,并通过增加优化解集中节点上的信息素量,加速求取最优解的收敛过程.最后,蚁群在迭代优化的基础上构建出解决无线传感器网络覆盖问题的健壮优化解,该优化解能够在能量有效性的基础上具备良好的覆盖有效性和较长的生命周期. 相似文献
17.
An immune-tabu hybrid algorithm for thermal unit commitment of electric power systems 总被引：1，自引：0，他引：1
This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment （TUC） problem in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in modem power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the objective function of the TUC problem is considered as an antigen and the solutions are considered as antibodies, which are determined by the affinity computation. The code length of an antibody is shortened by encoding the continuous operating time, and the optimum searching speed is improved. Each feasible individual in the immune algorithm （IA） is used as the initial solution of the tabu search （TS） algorithm after certain generations of IA iteration. As examples, the proposed method has been applied to several thermal unit systems for a period of 24 h. The computation results demonstrate the good global optimum searching performance of the proposed immune-tabu hybrid algorithm. The presented algorithm can also be used to solve other optimization problems in fields such as the chemical industry and the power industry. 相似文献
18.
This paper discusses a kind of optimal method used for searching flat panel display (FPD) scanning matrix. The method adopts
bionic algorithm: genetic algorithm (GA) and particle swarm optimization (PSO) algorithm. The method using single GA is more
time-consuming, and the search efficiency is low in later evolution; the PSO algorithm is easily falling into the local optimal
solution and appears the premature convergent phenomenon. Hence, a hybrid approach of GAPSO is found to optimize the search
for high grayscale weights scanning matrix. Finally in the acceptable time, it finds a weight scanning matrix (WSM) of 256
gray scales with Matlab, whose scanning efficiency reaches 94.73% and the linearity is very good. 相似文献
19.
20.
1 Introduction Support vector machine (SVM) is a powerful ma-chine learning tool capable of representing non-linearrelationships and producing models that generalizeswell to unseen data .SVMhave been applied widelyinmany fields[1]such as hand-written character recogni-tion ,text categorization,computer vision,speechrec-ognition and gene classification,etc. Despite this , using an SVM requires a certainamount of model selection,i.e.,selection of the ac-tual kernel and its parameters .In rec… 相似文献