evolutionary algorithms

进化算法
  • 文章类型: Journal Article
    人类社会工业的快速发展带来了空气污染,严重影响人类健康。PM2.5浓度是造成空气污染的主要因素之一。为了准确预测PM2.5微米,我们提出了一种基于STL-LOESS的改进的物质状态启发式算法(DSMS)训练的树突状神经元模型(DNM),即DS-DNM。首先,DS-DNM采用STL-LOESS进行数据预处理,从原始数据中获得三个特征量:季节性,趋势,和残余成分。然后,由DSMS训练的DNM预测残差值。最后,将三组特征量求和得到预测值。在性能测试实验中,使用五个真实世界的PM2.5浓度数据来测试DS-DNM。另一方面,4种训练算法和7种预测模型进行对比,验证了训练算法的合理性和预测模型的准确性,分别。实验结果表明,DS-DNM在PM2.5浓度预测问题中具有较强的竞争力。
    The rapid industrial development in the human society has brought about the air pollution, which seriously affects human health. PM2.5 concentration is one of the main factors causing the air pollution. To accurately predict PM2.5 microns, we propose a dendritic neuron model (DNM) trained by an improved state-of-matter heuristic algorithm (DSMS) based on STL-LOESS, namely DS-DNM. Firstly, DS-DNM adopts STL-LOESS for the data preprocessing to obtain three characteristic quantities from original data: seasonal, trend, and residual components. Then, DNM trained by DSMS predicts the residual values. Finally, three sets of feature quantities are summed to obtain the predicted values. In the performance test experiments, five real-world PM2.5 concentration data are used to test DS-DNM. On the other hand, four training algorithms and seven prediction models were selected for comparison to verify the rationality of the training algorithms and the accuracy of the prediction models, respectively. The experimental results show that DS-DNM has the more competitive performance in PM2.5 concentration prediction problem.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    对于基于决策变量分组的大规模多目标进化算法,挑战是设计一个稳定的分组策略,以平衡趋同和人口多样性。本文提出了一种具有两种替代优化方法的大规模多目标优化算法(LSMOEA-TM)。在LSMOEA-TM中,两种可供选择的优化方法,采用两种分组策略划分决策变量,用于高效求解大规模多目标优化问题。此外,本文介绍了一种基于贝叶斯的参数调整策略,通过优化提出的两种替代优化方法中的参数来降低计算成本。提出的LSMOEA-TM和四个有效的大规模多目标进化算法已在一组基准大规模多目标问题上进行了测试,统计结果证明了该算法的有效性。
    For large-scale multiobjective evolutionary algorithms based on the grouping of decision variables, the challenge is to design a stable grouping strategy to balance convergence and population diversity. This paper proposes a large-scale multiobjective optimization algorithm with two alternative optimization methods (LSMOEA-TM). In LSMOEA-TM, two alternative optimization methods, which adopt two grouping strategies to divide decision variables, are introduced to efficiently solve large-scale multiobjective optimization problems. Furthermore, this paper introduces a Bayesian-based parameter-adjusting strategy to reduce computational costs by optimizing the parameters in the proposed two alternative optimization methods. The proposed LSMOEA-TM and four efficient large-scale multiobjective evolutionary algorithms have been tested on a set of benchmark large-scale multiobjective problems, and the statistical results demonstrate the effectiveness of the proposed algorithm.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    在一个复杂的农业区,确定每块土地的合适作物,以最大化预期总利润是耕种管理的关键问题。然而,许多因素,如成本,产量,销售价格通常不确定,这导致精确的编程方法不切实际。在本文中,我们提出了一个作物种植规划的问题,其中不确定因素估计为模糊参数。我们采用了一种高效的进化算法,水波优化(WWO),为了解决这个问题,其中每个解决方案都是基于三个指标进行评估的,包括预期的,乐观和悲观的价值观,两者的结合使算法能够在不确定条件下搜索可靠的解。对华东地区一组农业区域的测试结果表明,与仅基于期望值的非模糊优化方法相比,我们的模糊优化方法的解决方案获得了显着更高的利润。
    In a complex agricultural region, determine the appropriate crop for each plot of land to maximize the expected total profit is the key problem in cultivation management. However, many factors such as cost, yield, and selling price are typically uncertain, which causes an exact programming method impractical. In this paper, we present a problem of crop cultivation planning, where the uncertain factors are estimated as fuzzy parameters. We adapt an efficient evolutionary algorithm, water wave optimization (WWO), to solve this problem, where each solution is evaluated based on three metrics including the expected, optimistic and pessimistic values, the combination of which enables the algorithm to search credible solutions under uncertain conditions. Test results on a set of agricultural regions in East China showed that the solutions of our fuzzy optimization approach obtained significantly higher profits than those of non-fuzzy optimization methods based on only the expected values.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    COVID-19大流行引起了全球警报。随着人工智能的进步,COVID-19的测试能力已经大大扩展,医院资源大幅缓解。在过去的几年里,计算机视觉研究集中在卷积神经网络(CNN)上,能显著提高图像分析能力。然而,CNN架构通常是手动设计的,具有在实践中稀缺的丰富专业知识。进化算法(EA)可以自动搜索正确的CNN架构,并自愿优化相关的超参数。EA搜索的网络可用于有效处理COVID-19计算机断层扫描图像,无需专家知识和手动设置。在本文中,我们提出了一种新的基于EA的算法,该算法具有动态搜索空间,以设计用于在致病检测前诊断COVID-19的最佳CNN架构.实验是在COVID-CT数据集上针对一系列最先进的CNN模型进行的。实验表明,通过所提出的基于EA的算法搜索的体系结构可实现最佳性能,而无需任何预处理操作。此外,我们通过实验发现,大量使用批量标准化可能会降低性能。这与手动设计CNN架构的常识方法形成对比,并将帮助手工制作CNN模型的相关专家在没有任何预处理操作的情况下实现最佳性能。
    The COVID-19 pandemic has caused a global alarm. With the advances in artificial intelligence, the COVID-19 testing capabilities have been greatly expanded, and hospital resources are significantly alleviated. Over the past years, computer vision researches have focused on convolutional neural networks (CNNs), which can significantly improve image analysis ability. However, CNN architectures are usually manually designed with rich expertise that is scarce in practice. Evolutionary algorithms (EAs) can automatically search for the proper CNN architectures and voluntarily optimize the related hyperparameters. The networks searched by EAs can be used to effectively process COVID-19 computed tomography images without expert knowledge and manual setup. In this paper, we propose a novel EA-based algorithm with a dynamic searching space to design the optimal CNN architectures for diagnosing COVID-19 before the pathogenic test. The experiments are performed on the COVID-CT data set against a series of state-of-the-art CNN models. The experiments demonstrate that the architecture searched by the proposed EA-based algorithm achieves the best performance yet without any preprocessing operations. Furthermore, we found through experimentation that the intensive use of batch normalization may deteriorate the performance. This contrasts with the common sense approach of manually designing CNN architectures and will help the related experts in handcrafting CNN models to achieve the best performance without any preprocessing operations.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    In this paper, we focus on the bandlimited graph signal sampling problem. To sample graph signals, we need to find small-sized subset of nodes with the minimal optimal reconstruction error. We formulate this problem as a subset selection problem, and propose an efficient Pareto Optimization for Graph Signal Sampling (POGSS) algorithm. Since the evaluation of the objective function is very time-consuming, a novel acceleration algorithm is proposed in this paper as well, which accelerates the evaluation of any solution. Theoretical analysis shows that POGSS finds the desired solution in quadratic time while guaranteeing nearly the best known approximation bound. Empirical studies on both Erdos-Renyi graphs and Gaussian graphs demonstrate that our method outperforms the state-of-the-art greedy algorithms.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    There has been substantial growth in research on the robot automation, which aims to make robots capable of directly interacting with the world or human. Robot learning for automation from human demonstration is central to such situation. However, the dependence of demonstration restricts robot to a fixed scenario, without the ability to explore in variant situations to accomplish the same task as in demonstration. Deep reinforcement learning methods may be a good method to make robot learning beyond human demonstration and fulfilling the task in unknown situations. The exploration is the core of such generalization to different environments. While the exploration in reinforcement learning may be ineffective and suffer from the problem of low sample efficiency. In this paper, we present Evolutionary Policy Gradient (EPG) to make robot learn from demonstration and perform goal oriented exploration efficiently. Through goal oriented exploration, our method can generalize robot learned skill to environments with different parameters. Our Evolutionary Policy Gradient combines parameter perturbation with policy gradient method in the framework of Evolutionary Algorithms (EAs) and can fuse the benefits of both, achieving effective and efficient exploration. With demonstration guiding the evolutionary process, robot can accelerate the goal oriented exploration to generalize its capability to variant scenarios. The experiments, carried out in robot control tasks in OpenAI Gym with dense and sparse rewards, show that our EPG is able to provide competitive performance over the original policy gradient methods and EAs. In the manipulator task, our robot can learn to open the door with vision in environments which are different from where the demonstrations are provided.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    The quality of solution sets generated by decomposition-based evolutionary multi-objective optimisation (EMO) algorithms depends heavily on the consistency between a given problem\'s Pareto front shape and the specified weights\' distribution. A set of weights distributed uniformly in a simplex often leads to a set of well-distributed solutions on a Pareto front with a simplex-like shape, but may fail on other Pareto front shapes. It is an open problem on how to specify a set of appropriate weights without the information of the problem\'s Pareto front beforehand. In this article, we propose an approach to adapt weights during the evolutionary process (called AdaW). AdaW progressively seeks a suitable distribution of weights for the given problem by elaborating several key parts in weight adaptation-weight generation, weight addition, weight deletion, and weight update frequency. Experimental results have shown the effectiveness of the proposed approach. AdaW works well for Pareto fronts with very different shapes: 1) the simplex-like, 2) the inverted simplex-like, 3) the highly nonlinear, 4) the disconnect, 5) the degenerate, 6) the scaled, and 7) the high-dimensional.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    背景:迫切需要制定目标,有效和方便的测量,以帮助临床医生准确识别运动迟缓。这项研究的目的是评估使用进化算法(EA)评估手指敲击运动迟缓(FT)的客观方法的准确性,并探讨其是否可用于识别早期帕金森病(PD)。
    方法:一百零七个PD,收集41例特发性震颤(ET)患者和49例正常对照(NC)。参与者执行了标准的FT任务,将两个电磁跟踪传感器连接到拇指和食指。来自传感器的读数被传输到平板电脑,随后使用EA进行分析。装置的输出(称为“PD-Monitor”)从-1至+1(其中较高的分数表明运动迟缓的严重程度更大)。同时,使用运动障碍协会赞助的帕金森病统一评定量表(MDS-UPDRS)FT项目的修订对运动迟缓进行临床评估.
    结果:随着MDS-UPDRSFT得分的增加,来自同一手侧的PD-Monitor评分相应增加。PD-Monitor评分与MDS-UPDRSFT评分相关性良好(右侧:r=0.819,P=0.000;左侧:r=0.783,P=0.000)。此外,97名患有MDS-UPDRSFT运动迟缓的PD患者和每个PD亚组(FT运动迟缓得分为1至3)的PD-Monitor评分均高于NC。受试者工作特征(ROC)曲线显示,PD-MonitorFT评分可以在右手中以高精度(≥89.7%)检测不同程度的运动迟缓。此外,PD-Monitor评分可以区分早期PD和NC,ROC曲线下面积大于或等于0.899。此外,没有运动迟缓的ET可以通过PD监测评分与PD区分开。在左侧发现PD-Monitor评分与改良的Hoehn和Yahr分期呈正相关。
    结论:我们的研究表明,使用来自EA的分类器的简单使用设备不仅可以用于准确测量PD中运动迟缓的不同严重程度,但也有可能区分早期PD和正常性。
    BACKGROUND: There is an urgent need for developing objective, effective and convenient measurements to help clinicians accurately identify bradykinesia. The purpose of this study is to evaluate the accuracy of an objective approach assessing bradykinesia in finger tapping (FT) that uses evolutionary algorithms (EAs) and explore whether it can be used to identify early stage Parkinson\'s disease (PD).
    METHODS: One hundred and seven PD, 41 essential tremor (ET) patients and 49 normal controls (NC) were recruited. Participants performed a standard FT task with two electromagnetic tracking sensors attached to the thumb and index finger. Readings from the sensors were transmitted to a tablet computer and subsequently analyzed by using EAs. The output from the device (referred to as \"PD-Monitor\") scaled from - 1 to + 1 (where higher scores indicate greater severity of bradykinesia). Meanwhile, the bradykinesia was rated clinically using the Movement Disorder Society-Sponsored Revision of the Unified Parkinson\'s Disease Rating Scale (MDS-UPDRS) FT item.
    RESULTS: With an increasing MDS-UPDRS FT score, the PD-Monitor score from the same hand side increased correspondingly. PD-Monitor score correlated well with MDS-UPDRS FT score (right side: r = 0.819, P = 0.000; left side: r = 0.783, P = 0.000). Moreover, PD-Monitor scores in 97 PD patients with MDS-UPDRS FT bradykinesia and each PD subgroup (FT bradykinesia scored from 1 to 3) were all higher than that in NC. Receiver operating characteristic (ROC) curves revealed that PD-Monitor FT scores could detect different severity of bradykinesia with high accuracy (≥89.7%) in the right dominant hand. Furthermore, PD-Monitor scores could discriminate early stage PD from NC, with area under the ROC curve greater than or equal to 0.899. Additionally, ET without bradykinesia could be differentiated from PD by PD-Monitor scores. A positive correlation of PD-Monitor scores with modified Hoehn and Yahr stage was found in the left hand sides.
    CONCLUSIONS: Our study demonstrated that a simple to use device employing classifiers derived from EAs could not only be used to accurately measure different severity of bradykinesia in PD, but also had the potential to differentiate early stage PD from normality.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    A wealth of research on resting-state functional MRI (R-fMRI) data has revealed modularity as a fundamental characteristic of the human brain functional network. The modular structure has recently been suggested to be overlapping, meaning that a brain region may engage in multiple modules. However, not only the overlapping modular structure remains inconclusive, the topological features and functional roles of overlapping regions are also poorly understood. To address these issues, the present work utilized the maximal-clique based multiobjective evolutionary algorithm to explore the overlapping modular structure of the R-fMRI data obtained from 57 young healthy adults. Without prior knowledge, brain regions were optimally grouped into eight modules with wide overlap. Based on the topological features captured by graph theory analyses, overlapping regions were classified into an integrated club and a dominant minority club through clustering. Functional flexibility analysis found that overlapping regions in both clubs were significantly more flexible than non-overlapping ones. Lesion simulations revealed that targeted attack at overlapping regions were more damaging than random failure or even targeted attack at hub regions. In particular, overlapping regions in the dominant minority club were more flexible and more crucial for information communication than the others were. Together, our findings demonstrated the highly organized overlapping modular architecture and revealed the importance as well as complexity of overlapping regions from both topological and functional aspects, which provides important implications for their roles in executing multiple tasks and maintaining information communication.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    Increased nutrient loads and changed nutrient ratios in estuarine waters have enhanced the occurrence of eutrophication and harmful algae blooms. Most of these consequences are caused by the new proliferation of toxin-producing non-siliceous algae. In this study, we propose a multi-objective reservoir operation model based on 10-day time scale for estuarine eutrophication control to reduce the potential non-siliceous algae outbreak. This model takes the hydropower generation and social economy water requirement in reservoir into consideration, minimizing the ICEP (indicator of estuarine eutrophication potential) as an ecological objective. Three modern multi-objective evolutionary algorithms (MOEAs) are applied to solve the proposed reservoir operation model. The Three Gorges Reservoir and its operation effects on the Yangtze Estuary were chosen as a case study. The performances of these three algorithms were evaluated through a diagnostic assessment framework of modern MOEAs\' abilities. The results showed that the multi-objective evolutionary algorithm based on decomposition with differential evolution operator (MOEA/D-DE) achieved the best performance for the operation model. It indicates that single implementation of hydrological management cannot make effective control of potential estuarine eutrophication, while combined in-estuary TP concentration control and reservoir optimal operation is a more realistic, crucial and effective strategy for controlling eutrophication potential of non-siliceous algae proliferation. Under optimized operation with controlled TP concentration and estuarine water withdrawal of 1470 m3/s, ecological satiety rate for estuarine drinking water source increased to 77.78%, 88.89% and 83.33% for wet, normal and dry years, the corresponding values in practical operation were only 72.22%, 58.33% and 55.56%, respectively. The results suggest that these operations will not negatively affect the economic and social interests. Therefore, the proposed integrated management approaches can provide guidance for water managers to reach a stable trophic control of estuarine waters.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

公众号