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A Time-Dependent Vehicle Routing Problem with Time Windows for E-Commerce Supplier Site Pickups Using Genetic Algorithm 被引量:3
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作者 Suresh Nanda Kumar Ramasamy Panneerselvam 《Intelligent Information Management》 2015年第4期181-194,共14页
The VRP is classified as an NP-hard problem. Hence exact optimization methods may be difficult to solve these problems in acceptable CPU times, when the problem involves real-world data sets that are very large. To ge... The VRP is classified as an NP-hard problem. Hence exact optimization methods may be difficult to solve these problems in acceptable CPU times, when the problem involves real-world data sets that are very large. To get solutions in determining routes which are realistic and very close to the actual solution, we use heuristics and metaheuristics which are of the combinatorial optimization type. A literature review of VRPTW, TDVRP, and a metaheuristic such as the genetic algorithm was conducted. In this paper, the implementation of the VRPTW and its extension, the time-dependent VRPTW (TDVRPTW) has been carried out using the model as well as metaheuristics such as the genetic algorithm (GA). The algorithms were implemented, using Matlab and HeuristicLab optimization software. A plugin was developed using Visual C# and DOT NET framework 4.5. Results were tested using Solomon’s 56 benchmark instances classified into groups such as C1, C2, R1, R2, RC1, RC2, with 100 customer nodes, 25 vehicles and each vehicle capacity of 200. The results were comparable to the earlier algorithms developed and in some cases the current algorithm yielded better results in terms of total distance travelled and the average number of vehicles used. 展开更多
关键词 Vehicle Routing Problem EXAcT Methods HEURISTIcS Metaheuristics VRPTW TDVRPTW Optimization Genetic algorithms Matlab HeuristicLab c# DOT NET
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Currency-based Iterative Multi-Agent Bidding Mechanism Based on Genetic Algorithm
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作者 M K LIM Z ZHANG 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期113-,共1页
This paper introduces a multi-agent system which i nt egrates process planning and production scheduling, in order to increase the fle xibility of manufacturing systems in coping with rapid changes in dynamic market a... This paper introduces a multi-agent system which i nt egrates process planning and production scheduling, in order to increase the fle xibility of manufacturing systems in coping with rapid changes in dynamic market and dealing with internal uncertainties such as machine breakdown or resources shortage. This system consists of various autonomous agents, each of which has t he capability of communicating with one another and making decisions based on it s knowledge and if necessary on information provided by other agents. Machine ag ents which represent the machines play an important role in the system in that t hey negotiate with each other to bid for jobs. An iterative bidding mechanism is proposed to facilitate the process of job assignment to machines and handle the negotiation between agents. This mechanism enables near optimal process plans a nd production schedules to be produced concurrently, so that dynamic changes in the market can be coped with at a minimum cost, and the utilisation of manufactu ring resources can be optimised. In addition, a currency scheme with currency-l ike metrics is proposed to encourage or prohibit machine agents to put forward t heir bids for the jobs announced. The values of the metrics are adjusted iterati vely so as to obtain an integrated plan and schedule which result in the minimum total production cost while satisfying products due dates. To deal with the optimisation problem, i.e. to what degree and how the currencies should be adj usted in each iteration, a genetic algorithm (GA) is developed. Comparisons are made between GA approach and simulated annealing (SA) optimisation technique. 展开更多
关键词 agile manufacturing multi-agent systems geneti c algorithm simulated annealing
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采用混合策略联合优化的模糊C-均值聚类信息熵点云简化算法 被引量:1
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作者 黄鹤 黄佳慧 +2 位作者 刘国权 王会峰 高涛 《西安交通大学学报》 EI CAS CSCD 北大核心 2024年第7期214-226,共13页
针对传统聚类算法处理点云简化问题时精度低、耗时长且易丢失特征信息等问题,提出了一种基于动态精英自适应混合策略的鹈鹕算法(DEAMPOA)与加权熵法联合优化的模糊C-均值聚类(FCM)信息熵点云简化算法。采用动态自适应种群混合策略,同时... 针对传统聚类算法处理点云简化问题时精度低、耗时长且易丢失特征信息等问题,提出了一种基于动态精英自适应混合策略的鹈鹕算法(DEAMPOA)与加权熵法联合优化的模糊C-均值聚类(FCM)信息熵点云简化算法。采用动态自适应种群混合策略,同时融合了精英反向化思路,显著提升了鹈鹕优化算法(POA)的收敛趋势和全局寻优能力,提高了寻找FCM最优聚类中心的成功率;利用DEAMPOA结合加权熵法对FCM进行优化,提高鲁棒性的同时增强了搜索精度,得到较好的聚类结果;在8种UCI标准数据集上与4种算法对比进行聚类性能评估实验,验证了所提方法综合性能优越;将所提方法与信息熵融合,并应用在三维点云KITTI数据集简化中。实验结果表明:与包围框简化法、随机采样简化法和特征选择简化法对比,所提方法全局误差简化前后点集之间平均欧式距离(MED)指标分别降低了2.25%、6.93%、5.74%,点云简化效果最优且运行速度满足要求。 展开更多
关键词 c-均值聚类 鹈鹕优化算法 点云简化 信息熵
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A Fixed Suppressed Rate Selection Method for Suppressed Fuzzy C-Means Clustering Algorithm 被引量:2
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作者 Jiulun Fan Jing Li 《Applied Mathematics》 2014年第8期1275-1283,共9页
Suppressed fuzzy c-means (S-FCM) clustering algorithm with the intention of combining the higher speed of hard c-means clustering algorithm and the better classification performance of fuzzy c-means clustering algorit... Suppressed fuzzy c-means (S-FCM) clustering algorithm with the intention of combining the higher speed of hard c-means clustering algorithm and the better classification performance of fuzzy c-means clustering algorithm had been studied by many researchers and applied in many fields. In the algorithm, how to select the suppressed rate is a key step. In this paper, we give a method to select the fixed suppressed rate by the structure of the data itself. The experimental results show that the proposed method is a suitable way to select the suppressed rate in suppressed fuzzy c-means clustering algorithm. 展开更多
关键词 HARD c-MEANS cLUSTERING algorithm FUZZY c-MEANS cLUSTERING algorithm Suppressed FUZZY c-MEANS cLUSTERING algorithm Suppressed RATE
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Automatic DNA sequencing for electrophoresis gels using image processing algorithms 被引量:1
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作者 Jiann-Der Lee Chung-Hsien Huang +1 位作者 Neng-Wei Wang Chin-Song Lu 《Journal of Biomedical Science and Engineering》 2011年第8期523-528,共6页
DNA electrophoresis gel is an important biologically experimental technique and DNA sequencing can be defined by it. Traditionally, it is time consuming for biologists to exam the gel images by their eyes and often ha... DNA electrophoresis gel is an important biologically experimental technique and DNA sequencing can be defined by it. Traditionally, it is time consuming for biologists to exam the gel images by their eyes and often has human errors during the process. Therefore, automatic analysis of the gel image could provide more information that is usually ignored by human expert. However, basic tasks such as the identification of lanes in a gel image, easily done by human experts, emerge as problems that may be difficult to be executed automatically. In this paper, we design an automatic procedure to analyze DNA gel images using various image processing algorithms. Firstly, we employ an enhanced fuzzy c-means algorithm to extract the useful information from DNA gel images and exclude the undesired background. Then, Gaussian function is utilized to estimate the location of each lane of A, T, C, and G on the gels images automatically. Finally, the location of each band on the gel image can be detected accurately by tracing lanes, renewing lost bands, and eliminating repetitive bands. 展开更多
关键词 DNA SEQUENcING FUZZY c-MEANS algorithm
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Research on Scholarship Evaluation System based on Decision Tree Algorithm 被引量:1
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作者 YIN Xiao WANG Ming-yu 《电脑知识与技术》 2015年第3X期11-13,共3页
Under the modern education system of China, the annual scholarship evaluation is a vital thing for many of the collegestudents. This paper adopts the classification algorithm of decision tree C4.5 based on the betteri... Under the modern education system of China, the annual scholarship evaluation is a vital thing for many of the collegestudents. This paper adopts the classification algorithm of decision tree C4.5 based on the bettering of ID3 algorithm and constructa data set of the scholarship evaluation system through the analysis of the related attributes in scholarship evaluation information.And also having found some factors that plays a significant role in the growing up of the college students through analysis and re-search of moral education, intellectural education and culture&PE. 展开更多
关键词 data mining scholarship evaluation system decision tree algorithm c4.5 algorithm
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Parallel discrete lion swarm optimization algorithm for solving traveling salesman problem 被引量:2
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作者 ZHANG Daoqing JIANG Mingyan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第4期751-760,共10页
As a typical representative of the NP-complete problem, the traveling salesman problem(TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optim... As a typical representative of the NP-complete problem, the traveling salesman problem(TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optimization(DLSO) algorithm is proposed to solve the TSP. Firstly, we introduce discrete coding and order crossover operators in DLSO. Secondly, we use the complete 2-opt(C2-opt) algorithm to enhance the local search ability.Then in order to enhance the efficiency of the algorithm, a parallel discrete lion swarm optimization(PDLSO) algorithm is proposed.The PDLSO has multiple populations, and each sub-population independently runs the DLSO algorithm in parallel. We use the ring topology to transfer information between sub-populations. Experiments on some benchmarks TSP problems show that the DLSO algorithm has a better accuracy than other algorithms, and the PDLSO algorithm can effectively shorten the running time. 展开更多
关键词 discrete lion swarm optimization(DLSO)algorithm complete 2-opt(c2-opt)algorithm parallel discrete lion swarm optimization(PDLSO)algorithm traveling salesman problem(TSP)
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基于模糊c-均值聚类的亚热带丘陵区土壤肥力空间分异与管理分区
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作者 赖佳鑫 李康祺 +3 位作者 周萍 戴玉婷 郭晓彬 吴金水 《植物营养与肥料学报》 CAS CSCD 北大核心 2024年第4期702-716,共15页
[目的]亚热带丘陵区地形复杂,土壤肥力空间变异大,科学地将土壤按照相似地力进行分区,是实现丘陵区土壤精确管理,优化土壤培肥技术的理论基础。[方法]研究对象位于亚热带丘陵区的典型小流域-湖南省长沙县金井镇,2009年在全镇范围内(112 ... [目的]亚热带丘陵区地形复杂,土壤肥力空间变异大,科学地将土壤按照相似地力进行分区,是实现丘陵区土壤精确管理,优化土壤培肥技术的理论基础。[方法]研究对象位于亚热带丘陵区的典型小流域-湖南省长沙县金井镇,2009年在全镇范围内(112 km~2)密集布置946个样点采集土壤样品,以测定的土壤肥力指标为数据源,包括土壤有机碳(SOC)、全氮(TN)、全磷(TP)、速效氮(AN)、有效磷(AP)和pH,采用地统计学和模糊c-均值聚类算法,分析流域土壤肥力的空间异质性;采用主成分分析法进行土壤肥力分区,并根据数据的差异显著性和变异系数对分区结果进行验证。[结果]除pH外,流域内土壤有机碳、全氮、全磷、速效氮和有效磷均存在中等至强的空间变异,变异系数(CV)介于36%~125%。基于主成分分析和模糊c-均值聚类可将研究区划分为3个肥力管理分区:MZ1、MZ2和MZ3,分区后各土壤肥力指标的变异系数(CV)不同程度地降低,以pH变异系数降幅最小(6%),AP变异系数降幅最大(96%)。同一分区内主要土壤肥力指标趋于同质化,分区间则异质化显著(P<0.01)。分区间水稻产量差异明显,MZ1区晚稻产量和早晚稻总产量显著高于MZ2和MZ3 (P<0.01)。MZ1、MZ2和MZ3区土壤pH值分别为4.12、4.04和4.00,均属于极酸水平;SOC分别为15.15、14.38和12.24 g/kg,均处于高水平;TN也为高水平(1.56、1.48和1.34 g/kg);TP为高至很高水平(0.86、0.69和0.60 g/kg);AN则处于很低至低水平(41.08、35.33和26.16 mg/kg);AP为中低水平(8.63、4.46和3.39 mg/kg)。[结论]亚热带丘陵区地形地貌复杂,是土壤肥力空间变异较大的主要影响因素。通过土壤肥力管理分区,可有效降低区域内肥力指标的变异程度,优化复杂丘陵区耕地管理措施。本研究区域中MZ1、MZ2和MZ3区均应着重改良土壤酸化现象,提高肥料氮素利用率,避免过量施用化学氮肥;MZ1区可适当减施磷肥,避免关键生育期过量施用磷肥;MZ2和MZ3区可以考虑适量施用生物酶活化磷肥或增施有机肥,以提高作物对磷素的利用效率。 展开更多
关键词 土壤肥力分区 空间分异 模糊聚类 主成分分析 养分管理措施
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基于平滑因子引入和神经网络优化的锂电池SOC估计方法
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作者 付炳喆 李沂洹 +1 位作者 王玮 李慷 《电源技术》 CAS 北大核心 2024年第1期143-149,共7页
为提高锂电池荷电状态(SOC)的估计精度,提出了一种基于平滑因子引入和神经网络优化的锂电池SOC估计方法。将黄金分割优选法和模糊C均值聚类算法应用于RBF神经网络,分别用来确定最佳隐含层神经元个数和径向基中心;采用遗传算法对高斯核... 为提高锂电池荷电状态(SOC)的估计精度,提出了一种基于平滑因子引入和神经网络优化的锂电池SOC估计方法。将黄金分割优选法和模糊C均值聚类算法应用于RBF神经网络,分别用来确定最佳隐含层神经元个数和径向基中心;采用遗传算法对高斯核函数宽度及连接权值进行优化,解决了RBF神经网络结构和初始参数难以确定的问题。将滑动时间窗口内的放电容量作为平滑因子引入神经网络模型,增强了RBF网络对锂离子电池非线性特性拟合的能力。基于实验获得的锂离子电池在联邦城市行车计划(FUDS)工况下的数据,对所提出的方法进行仿真和验证,结果表明,所提方法显著提升了锂电池SOC的估计精度。 展开更多
关键词 电池荷电状态 径向基神经网络 遗传算法 模糊c均值聚类 黄金分割优选法
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A Hybrid Multifarious Clustering Algorithm for the Analysis of Memmogram Images
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作者 T. Velmurugan E. Venkatesan 《Journal of Computer and Communications》 2019年第12期136-151,共16页
A number of clustering algorithms were used to analyze many databases in the field of image clustering. The main objective of this research work was to perform a comparative analysis of the two of the existing partiti... A number of clustering algorithms were used to analyze many databases in the field of image clustering. The main objective of this research work was to perform a comparative analysis of the two of the existing partitions based clustering algorithms and a hybrid clustering algorithm. The results verification done by using classification algorithms via its accuracy. The perfor-mance of clustering and classification algorithms were carried out in this work based on the tumor identification, cluster quality and other parameters like run time and volume complexity. Some of the well known classification algorithms were used to find the accuracy of produced results of the clustering algorithms. The performance of the clustering algorithms proved mean-ingful in many domains, particularly k-Means, FCM. In addition, the proposed multifarious clustering technique has revealed their efficiency in terms of performance in predicting tumor affected regions in mammogram images. The color images are converted in to gray scale images and then it is processed. Finally, it is identified the best method for the analysis of finding tumor in breast images. This research would be immensely useful to physicians and radiologist to identify cancer affected area in the breast. 展开更多
关键词 MEDIcAL IMAGES HYBRID clusteing algorithm K-MEANS algorithm Fuzzy c Means algorithm classification algorithms
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基于FCM和EO-SVM水轮机尾水管压力脉动特征识别 被引量:1
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作者 刘茜媛 王利英 +1 位作者 张路遥 曹庆皎 《水电能源科学》 北大核心 2024年第1期162-165,共4页
为有效识别水轮机尾水管压力脉动特征,提出了一种基于模糊C均值聚类、平衡优化器算法与支持向量机的识别方法。该方法首先采用平衡优化器算法优化SVM的惩罚因子和核函数以获得更好的SVM参数组合,构建EO-SVM识别模型以实现其在水轮机尾... 为有效识别水轮机尾水管压力脉动特征,提出了一种基于模糊C均值聚类、平衡优化器算法与支持向量机的识别方法。该方法首先采用平衡优化器算法优化SVM的惩罚因子和核函数以获得更好的SVM参数组合,构建EO-SVM识别模型以实现其在水轮机尾水管压力脉动特征识别中的应用。然后采用模糊C均值聚类算法将待分类的压力脉动特征进行初始聚类,将其分为四类,并依据聚类结果选择最靠近每类中心的样本作为EO-SVM模型的训练样本。将SVM和EO-SVM两种模型的识别分类结果进行比较,验证了所提EO-SVM模型的有效性。 展开更多
关键词 压力脉动 小波包分析 模糊c均值聚类 平衡优化器算法 支持向量机
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基于放电曲线和模糊C均值法的退役电池一致性分选方法
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作者 赵光金 孟高军 +2 位作者 董锐锋 苏令 张正 《电源技术》 CAS 北大核心 2024年第9期1769-1776,共8页
在电动汽车井喷式增长的背景下,巨量退役的动力电池如何回收成为当前电动汽车行业亟待解决的问题。考虑到退役电池容量、内阻等性能会出现较大的不一致性,在对退役电池梯次利用前,有必要根据其性能状况进行一致性分选,以实现退役电池的... 在电动汽车井喷式增长的背景下,巨量退役的动力电池如何回收成为当前电动汽车行业亟待解决的问题。考虑到退役电池容量、内阻等性能会出现较大的不一致性,在对退役电池梯次利用前,有必要根据其性能状况进行一致性分选,以实现退役电池的经济效益和利用率最大化。提出了一种基于放电曲线和改进模糊C均值算法的退役电池一致性分选方法。该方法以退役电池单体为研究对象,借助1 C充放电实验选取放电曲线,进行特征参数提取;在此基础上,结合改进的模糊C均值算法构建退役电池高精度分选模型,基于简化的特征点提取过程,在不同容量梯度的退役电池下对分选方法的可行性进行了验证。 展开更多
关键词 退役动力电池 放电曲线 一致性分选 特征参数 模糊c均值算法
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基于FCM及快速迭代收缩阈值算法的平面ECT图像重建
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作者 张立峰 唐志浩 《计量学报》 CSCD 北大核心 2024年第6期899-906,共8页
为提高平面阵列电容成像系统的成像精度,提出一种基于模糊C均值聚类(FCM)进行数据优化的快速迭代收缩阈值算法(FISTA)。根据平面阵列电容数据的特点,首先利用FCM算法对测量电容值进行分类,保留有效电容值,实现电容向量降维;然后利用离... 为提高平面阵列电容成像系统的成像精度,提出一种基于模糊C均值聚类(FCM)进行数据优化的快速迭代收缩阈值算法(FISTA)。根据平面阵列电容数据的特点,首先利用FCM算法对测量电容值进行分类,保留有效电容值,实现电容向量降维;然后利用离散小波基(DWT)对灰度值进行稀疏表示,并建立L1正则化模型,采用FISTA进行求解,以实现图像重建;最后将FCM处理后的电容值分别用于Landweber算法、Tikhonov算法进行重建对比。仿真与实验结果表明,该算法重建图像的平均相对误差约为0.0527,平均相关系数约为0.9422,均优于其它算法,且重建图像伪影较少,更接近真实情况;因此,所提算法具有更好的重建效果。。 展开更多
关键词 电容层析成像 平面阵列电容 图像重建 模糊c均值聚类 快速迭代收缩阈值算法 缺陷检测
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基于改进模糊C均值聚类与SMO算法的地铁轨道健康状态评价
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作者 许以凯 杨艺 +2 位作者 张明凯 赵才友 万壮 《铁道标准设计》 北大核心 2024年第11期53-59,共7页
轨道健康状态评价技术对于保障列车的运行安全与乘客的舒适性有重要意义,为寻求一种新的轨道设备综合评价方法,实现对轨道健康状态的科学评价,提出一种基于改进模糊C均值聚类和序列最小优化算法(SMO)构建轨道健康状态评估分析模型。该... 轨道健康状态评价技术对于保障列车的运行安全与乘客的舒适性有重要意义,为寻求一种新的轨道设备综合评价方法,实现对轨道健康状态的科学评价,提出一种基于改进模糊C均值聚类和序列最小优化算法(SMO)构建轨道健康状态评估分析模型。该模型首先提出包含轨道几何状态和结构状态的综合评价指标体系;其次采用变异系数法计算评价指标的权重系数并代入模糊C均值聚类法,得到各轨道样本的分类结果;在此基础上,再利用序列最小优化算法通过划分数据对轨道健康状态进行评价;最后通过实例分析对该评价模型进行验证并开展研究。研究结果表明,经模型评价的855个轨道单元评价结果中优良比例为94%,预测效果良好,平均误差为5%,进而验证了该模型的指标体系和评价方法的科学性和合理性,并给出了进一步研究优化的方向。本文对各轨道指标统筹综合评价,为地铁轨道工务管理线路质量评价提供一种新思路,使轨道设备管理变得有序可控,减少人力、物力资源的浪费。 展开更多
关键词 地铁 轨道 健康状态评价 变异系数法 模糊c均值聚类 SMO算法
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Distributed C-Means Algorithm for Big Data Image Segmentation on a Massively Parallel and Distributed Virtual Machine Based on Cooperative Mobile Agents
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作者 Fatéma Zahra Benchara Mohamed Youssfi +2 位作者 Omar Bouattane Hassan Ouajji Mohammed Ouadi Bensalah 《Journal of Software Engineering and Applications》 2015年第3期103-113,共11页
The aim of this paper is to present a distributed algorithm for big data classification, and its application for Magnetic Resonance Images (MRI) segmentation. We choose the well-known classification method which is th... The aim of this paper is to present a distributed algorithm for big data classification, and its application for Magnetic Resonance Images (MRI) segmentation. We choose the well-known classification method which is the c-means method. The proposed method is introduced in order to perform a cognitive program which is assigned to be implemented on a parallel and distributed machine based on mobile agents. The main idea of the proposed algorithm is to execute the c-means classification procedure by the Mobile Classification Agents (Team Workers) on different nodes on their data at the same time and provide the results to their Mobile Host Agent (Team Leader) which computes the global results and orchestrates the classification until the convergence condition is achieved and the output segmented images will be provided from the Mobile Classification Agents. The data in our case are the big data MRI image of size (m × n) which is splitted into (m × n) elementary images one per mobile classification agent to perform the classification procedure. The experimental results show that the use of the distributed architecture improves significantly the big data segmentation efficiency. 展开更多
关键词 Multi-Agent System DISTRIBUTED algorithm BIG Data IMAGE Segmentation MRI IMAGE c-MEANS algorithm Mobile Agent
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Agent Based Segmentation of the MRI Brain Using a Robust C-Means Algorithm
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作者 Hanane Barrah Abdeljabbar Cherkaoui Driss Sarsri 《Journal of Computer and Communications》 2016年第10期13-21,共9页
In the last decade, the MRI (Magnetic Resonance Imaging) image segmentation has become one of the most active research fields in the medical imaging domain. Because of the fuzzy nature of the MRI images, many research... In the last decade, the MRI (Magnetic Resonance Imaging) image segmentation has become one of the most active research fields in the medical imaging domain. Because of the fuzzy nature of the MRI images, many researchers have adopted the fuzzy clustering approach to segment them. In this work, a fast and robust multi-agent system (MAS) for MRI segmentation of the brain is proposed. This system gets its robustness from a robust c-means algorithm (RFCM) and obtains its fastness from the beneficial properties of agents, such as autonomy, social ability and reactivity. To show the efficiency of the proposed method, we test it on a normal brain brought from the BrainWeb Simulated Brain Database. The experimental results are valuable in both robustness to noise and running times standpoints. 展开更多
关键词 Agents and MAS MR Images Fuzzy clustering c-Means algorithm Image Segmentation
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Optimal Approximation Algorithms for Reoptimization of Constraint Satisfaction Problems
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作者 Victor Alex Mikhailyuk 《American Journal of Operations Research》 2013年第2期279-288,共10页
The purpose of reoptimization using approximation methods—application of knowledge about the solution of the initial instance I, provided to achieve a better quality of approximation (approximation ratio) of an algor... The purpose of reoptimization using approximation methods—application of knowledge about the solution of the initial instance I, provided to achieve a better quality of approximation (approximation ratio) of an algorithm for determining optimal or close to it solutions of some “minor” changes of instance I. To solve the problem Ins-Max-EkCSP-P (reoptimization of Max-EkCSP-P with the addition of one constraint) with approximation resistant predicate P exists a polynomial threshold (optimal) -approximation algorithm, where the threshold “random” approximation ratio of P). When the unique games conjecture (UGC) is hold there exists a polynomial threshold (optimal) -approximation algorithm (where and the integrality gap of semidefinite relaxation of Max-EkCSP-P problem Z) to solve the problem Ins-Max-EkCSP-P. 展开更多
关键词 c-Approximation algorithm REOPTIMIZATION APPROXIMATION Resistant Predicates INTEGRALITY Gap UNIQUE Games cONJEcTURE (UGc)
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基于模糊C均值聚类的异构数据信息检索仿真
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作者 刘亮龙 牛秦洲 《计算机仿真》 2024年第10期482-486,共5页
不同数据库系统可能使用不同查询语义和查询表达方式,为了获取高质量的异构数据库信息检索结果,提出一种混合云环境下异构数据库信息检索算法。优先建立局部本体,在局部本体的基础上形成信息领域本体,抽取局部信息。在信息领域本体的指... 不同数据库系统可能使用不同查询语义和查询表达方式,为了获取高质量的异构数据库信息检索结果,提出一种混合云环境下异构数据库信息检索算法。优先建立局部本体,在局部本体的基础上形成信息领域本体,抽取局部信息。在信息领域本体的指导下对局部信息展开集成,获取全局信息,完成混合云环境下异构数据库信息集成。通过对全部信息展开检索特征匹配,组建异构数据库空间规划模型,采用模糊C均值聚类算法对信息聚类,最终实现混合云环境下异构数据库信息检索。实验结果表明,采用所提算法展开异构数据库信息检索的精度更高,且相对检索增益较高,说明其检索效果较好。 展开更多
关键词 混合云 异构数据库 信息检索 模糊聚类算法
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基于改进模糊C-均值聚类的陆上风电场集电线路回路划分与拓扑结构优化
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作者 易海 吕宙安 +5 位作者 张伶俐 陈希 柳典 黄雨薇 韩星星 许昌 《发电技术》 CSCD 2024年第4期675-683,共9页
【目的】在“双碳”目标以及我国能源结构加速转型的双重驱动下,风电产业规模不断快速增长,亟须降本增效以应对平价上网压力。集电线路的造价在投资中占比较大,存在可观的优化空间。为了降低投资成本,提出了一种改进模糊C-均值(fuzzy C-... 【目的】在“双碳”目标以及我国能源结构加速转型的双重驱动下,风电产业规模不断快速增长,亟须降本增效以应对平价上网压力。集电线路的造价在投资中占比较大,存在可观的优化空间。为了降低投资成本,提出了一种改进模糊C-均值(fuzzy C-means,FCM)聚类算法。【方法】利用改进FCM聚类算法对陆上风电场集电线路回路进行划分。该算法综合考虑了方位角与欧式距离,以保障回路间线路不交叉,并使相邻机组聚集到同一回路;引入机位到聚类中心距离的修正因子,通过调节其数值限制回路容量。在回路划分的基础上,利用动态Prim算法对各回路进行集电线路优化选线。最后,通过某陆上风电场算例验证方法的有效性。【结果】与只考虑方位角的聚类方法相比,考虑方位角和间距的改进FCM算法优化效果更好,单回、双回连接对应的集电线路总造价分别降低了2.6%和5.4%。【结论】所提算法能够有效降低集电线路的总造价,具有一定的应用价值,可为风电场集电线路设计提供参考。 展开更多
关键词 陆上风电场 集电线路 拓扑结构优化 模糊c-均值(FcM)聚类算法 动态Prim算法
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基于GAIFWFCM和TFNs的协同过滤算法
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作者 金玉 徐新卫 +2 位作者 陶飞 韩业 陈荣凯 《南阳理工学院学报》 2024年第4期49-57,共9页
针对传统推荐系统中使用离散评分未能合理表达用户偏好的问题,将遗传算法引入优化特征加权模糊C均值,通过梯形模糊聚合相似目标用户,提出基于遗传算法的优化加权模糊C均值聚类融合梯形模糊数的协同过滤模型。通过遗传算法进行增强初始... 针对传统推荐系统中使用离散评分未能合理表达用户偏好的问题,将遗传算法引入优化特征加权模糊C均值,通过梯形模糊聚合相似目标用户,提出基于遗传算法的优化加权模糊C均值聚类融合梯形模糊数的协同过滤模型。通过遗传算法进行增强初始聚类中心,利用优化加权模糊C均值聚类融合梯形模糊数,分析类内与类间属性特征关系,实现用户精细划分,合理过滤推荐。在两组数据集中以MAE和RMSE作为评估指标进行实验,实验结果表明,所提算法在与其余6种算法对比中分类误差更低,对用户意愿识别更加清晰。 展开更多
关键词 协同过滤 梯形模糊数 模糊c均值 遗传算法 特征加权
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