multi-objective optimization

多目标优化
  • 文章类型: Journal Article
    本文讨论了放置在智能配电系统中的基于柔性可再生能源的虚拟发电厂的有功和无功功率的同时管理,基于经济,操作,和配电系统运营商的电压安全目标。制定的问题旨在指定能源成本的最小加权总和,能量损失,和电压安全指标,考虑最优潮流模型,电压安全配方,以及虚拟电厂的运行模型。虚拟单元包括可再生能源,像风力系统一样,光伏,和生物废物单位。灵活性资源包括电动汽车停车场和基于价格的需求响应。在上述方案中,负载参数,可再生能源,电动汽车,能源价格是不确定的。本文利用无迹变换方法对不确定性进行建模。模糊决策用于提取折衷解决方案。所建议的方法创新性地考虑了具有电动汽车和基于价格的需求响应的虚拟单元的有功功率和无功功率的同时管理。这是为了促进经济,操作,和网络安全目标。根据数值结果,可再生能源虚拟单元的最佳电力管理方法能够促进经济,操作,和电压安全状态的网络约43%,47-62%,和26.9%,分别,功率流研究。只有基于价格的需求响应才能提高电压安全性,操作,网络的经济状况下降了约19.5%,35-47%,44%,分别,与潮流模型相比。
    This paper discusses the simultaneous management of active and reactive power of a flexible renewable energy-based virtual power plant placed in a smart distribution system, based on the economic, operational, and voltage security objectives of the distribution system operator. The formulated problem aims to specify the minimum weighted sum of energy cost, energy loss, and voltage security index, considering the optimal power flow model, voltage security formulation, and the operating model of the virtual power plant. The virtual unit includes renewable sources, like wind systems, photovoltaic, and bio-waste units. Flexibility resources include electric vehicle parking lot and price-based demand response. In the mentioned scheme, parameters of load, renewable sources, electric vehicles, and energy prices are uncertain. This paper utilizes the Unscented Transformation method for modeling uncertainties. Fuzzy decision-making is utilized to extract a compromised solution. The suggested approach innovatively considers the simultaneous management of active and reactive power of a virtual unit with electric vehicles and price-based demand response. This is performed to promote economic, operational, and network security objectives. According to numerical results, the approach with optimal power management of renewable virtual units is capable of boosting the economic, operation, and voltage security status of the network by approximately 43%, 47-62%, and 26.9%, respectively, to power flow studies. Only price-based demand response can improve the voltage security, operation, and economic states of the network by about 19.5%, 35-47%, and 44%, respectively, compared to the power flow model.
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  • 文章类型: Journal Article
    植物育种是一项复杂的工作,本质上几乎总是多目标的。近年来,随机育种模拟已被育种者用来评估替代育种策略的优点并协助决策。除了模拟,多个竞争育种目标的帕累托边界的可视化可以帮助育种者做出决策。本文介绍了Python育种优化器和模拟器(PyBrOpS),一个Python软件包,能够执行育种目标的多目标优化和育种管道的随机模拟。PyBrOpS在其他模拟平台中是独一无二的,因为它可以执行多目标优化,并将这些结果纳入育种模拟。PyBrOpS是高度模块化的,具有基于脚本的理念,使其高度可扩展和可定制。在本文中,我们描述了PyBrOpS的一些主要特征,并展示了其在帕累托边界上绘制育种可能性并在模拟育种管道中执行多目标选择的能力。
    Plant breeding is a complex endeavor that is almost always multi-objective in nature. In recent years, stochastic breeding simulations have been used by breeders to assess the merits of alternative breeding strategies and assist in decision making. In addition to simulations, visualization of a Pareto frontier for multiple competing breeding objectives can assist breeders in decision making. This paper introduces Python Breeding Optimizer and Simulator (PyBrOpS), a Python package capable of performing multi-objective optimization of breeding objectives and stochastic simulations of breeding pipelines. PyBrOpS is unique among other simulation platforms in that it can perform multi-objective optimizations and incorporate these results into breeding simulations. PyBrOpS is built to be highly modular and has a script-based philosophy, making it highly extensible and customizable. In this paper, we describe some of the main features of PyBrOpS and demonstrate its ability to map Pareto frontiers for breeding possibilities and perform multi-objective selection in a simulated breeding pipeline.
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  • 文章类型: Journal Article
    神经网络修剪是降低深度神经网络计算复杂度的流行方法。近年来,随着越来越多的证据表明,传统的网络修剪方法采用了不适当的代理度量,随着新型硬件越来越多,在网络修剪的循环中结合硬件特性的硬件感知网络修剪已获得越来越多的关注。网络精度和硬件效率(延迟、内存消耗,等。)是网络修剪成功的关键目标,但是多个目标之间的冲突使得不可能找到一个最优解。以前的研究大多将硬件感知的网络修剪转换为具有单一目标的优化问题。在本文中,我们建议使用多目标进化算法(MOEA)来解决硬件感知的网络修剪问题。具体来说,我们将问题表述为多目标优化问题,并提出了一个新颖的模因MOEA,即HAMP,结合了有效的基于投资组合的选择和代理辅助的本地搜索,来解决它。实证研究表明,与最先进的硬件感知网络修剪方法相比,MOEA在同时提供一组替代解决方案方面的潜力以及HAMP的优越性。
    Neural network pruning is a popular approach to reducing the computational complexity of deep neural networks. In recent years, as growing evidence shows that conventional network pruning methods employ inappropriate proxy metrics, and as new types of hardware become increasingly available, hardware-aware network pruning that incorporates hardware characteristics in the loop of network pruning has gained growing attention. Both network accuracy and hardware efficiency (latency, memory consumption, etc.) are critical objectives to the success of network pruning, but the conflict between the multiple objectives makes it impossible to find a single optimal solution. Previous studies mostly convert the hardware-aware network pruning to optimization problems with a single objective. In this paper, we propose to solve the hardware-aware network pruning problem with Multi-Objective Evolutionary Algorithms (MOEAs). Specifically, we formulate the problem as a multi-objective optimization problem, and propose a novel memetic MOEA, namely HAMP, that combines an efficient portfolio-based selection and a surrogate-assisted local search, to solve it. Empirical studies demonstrate the potential of MOEAs in providing simultaneously a set of alternative solutions and the superiority of HAMP compared to the state-of-the-art hardware-aware network pruning method.
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  • 文章类型: Journal Article
    由于其高可靠性,研究人员越来越关注可再生能源,能源独立,效率,和环境效益。本文介绍了一种用于微电网(MGs)短期调度的新颖多目标框架,它解决了最小化运营费用和减少污染排放的相互矛盾的目标。核心贡献是混沌自适应正弦余弦算法(CSASCA)的开发。该算法同时生成Pareto最优解,有效地平衡成本降低和减排。该问题被表述为具有降低成本和环境保护目标的复杂多目标优化任务。为了增强算法内的决策,结合了模糊逻辑。CSASCA的性能在三种情况下进行评估:(1)全功率运行的光伏和风力机组,(2)所有在规定范围内运行的机组,不受限制的公用电力交换,(3)仅使用非零排放能源的微电网运行。第三种情况强调了算法在先前研究中未涵盖的具有挑战性的背景下的功效。使用三个测试示例将这些场景的仿真结果与传统的正弦余弦算法(SCA)和其他最新的优化方法进行比较。CSASCA的创新之处在于其混沌的自适应机制,这显著提高了优化性能。这些机制的整合导致了卓越的运营成本解决方案,排放,和执行时间。具体来说,在第一种情况下,CSASCA的成本和排放量的最佳值分别为590.45€ct和337.28kg,在第二种情况下,成本为98.203€ct,排放量为406.204kg,在第三种情况下,成本为95.38€ct,排放量为982.173kg。总的来说,CSASCA通过提供增强的探索优于传统SCA,改进的收敛性,有效的约束处理,和降低的参数灵敏度,使其成为解决微电网调度等多目标优化问题的有力工具。
    Researchers are increasingly focusing on renewable energy due to its high reliability, energy independence, efficiency, and environmental benefits. This paper introduces a novel multi-objective framework for the short-term scheduling of microgrids (MGs), which addresses the conflicting objectives of minimizing operating expenses and reducing pollution emissions. The core contribution is the development of the Chaotic Self-Adaptive Sine Cosine Algorithm (CSASCA). This algorithm generates Pareto optimal solutions simultaneously, effectively balancing cost reduction and emission mitigation. The problem is formulated as a complex multi-objective optimization task with goals of cost reduction and environmental protection. To enhance decision-making within the algorithm, fuzzy logic is incorporated. The performance of CSASCA is evaluated across three scenarios: (1) PV and wind units operating at full power, (2) all units operating within specified limits with unrestricted utility power exchange, and (3) microgrid operation using only non-zero-emission energy sources. This third scenario highlights the algorithm\'s efficacy in a challenging context not covered in prior research. Simulation results from these scenarios are compared with traditional Sine Cosine Algorithm (SCA) and other recent optimization methods using three test examples. The innovation of CSASCA lies in its chaotic self-adaptive mechanisms, which significantly enhance optimization performance. The integration of these mechanisms results in superior solutions for operation cost, emissions, and execution time. Specifically, CSASCA achieves optimal values of 590.45 €ct for cost and 337.28 kg for emissions in the first scenario, 98.203 €ct for cost and 406.204 kg for emissions in the second scenario, and 95.38 €ct for cost and 982.173 kg for emissions in the third scenario. Overall, CSASCA outperforms traditional SCA by offering enhanced exploration, improved convergence, effective constraint handling, and reduced parameter sensitivity, making it a powerful tool for solving multi-objective optimization problems like microgrid scheduling.
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  • 文章类型: Journal Article
    随着大流行继续对全球公共卫生构成挑战,发展有效的预测模型已经成为一个迫切的研究课题。本研究旨在探讨多目标优化方法在选择传染病预测模型中的应用,并评价其对提高预测精度的影响,概括性,和计算效率。在这项研究中,使用NSGA-II算法将多目标优化选择的模型与传统单目标优化选择的模型进行比较。结果表明,通过多目标优化方法选择的决策树(DT)和极值梯度提升回归器(XGBoost)模型在准确性方面优于其他方法选择的模型。概括性,和计算效率。与通过单目标优化方法选择的岭回归模型相比,决策树(DT)和XGBoost模型在真实数据集上显示出显着较低的均方根误差(RMSE)。这一发现凸显了多目标优化在平衡多个评估指标方面的潜在优势。然而,这项研究的局限性表明了未来的研究方向,包括算法改进,扩展的评估指标,以及使用更多样化的数据集。本研究的结论强调了多目标优化方法在公共卫生决策支持系统中的理论和现实意义,表明了它们在选择预测模型方面的广泛潜在应用。
    As the pandemic continues to pose challenges to global public health, developing effective predictive models has become an urgent research topic. This study aims to explore the application of multi-objective optimization methods in selecting infectious disease prediction models and evaluate their impact on improving prediction accuracy, generalizability, and computational efficiency. In this study, the NSGA-II algorithm was used to compare models selected by multi-objective optimization with those selected by traditional single-objective optimization. The results indicate that decision tree (DT) and extreme gradient boosting regressor (XGBoost) models selected through multi-objective optimization methods outperform those selected by other methods in terms of accuracy, generalizability, and computational efficiency. Compared to the ridge regression model selected through single-objective optimization methods, the decision tree (DT) and XGBoost models demonstrate significantly lower root mean square error (RMSE) on real datasets. This finding highlights the potential advantages of multi-objective optimization in balancing multiple evaluation metrics. However, this study\'s limitations suggest future research directions, including algorithm improvements, expanded evaluation metrics, and the use of more diverse datasets. The conclusions of this study emphasize the theoretical and practical significance of multi-objective optimization methods in public health decision support systems, indicating their wide-ranging potential applications in selecting predictive models.
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  • 文章类型: Journal Article
    这项研究旨在解决多能耦合微电网的优化和运营挑战,以提高系统的稳定性和可靠性。在分析了综合能源系统中此类系统的要求后,提出了一种改进的烟花算法(IFWA)。该算法将自适应资源分配策略与社区遗传策略相结合,根据个人优化状态自动调整爆炸范围和火花量,以满足实际需要。此外,构建了考虑有功电网损耗和静态电压的多目标优化模型,利用混合蛙跳算法(SFLA)求解约束多目标优化问题。通过对典型北方综合能源系统的模拟实验,以T=24的调度周期进行,验证了IFWA-SFLA的可行性和优越性。结果表明,IFWA-SFLA在优化微电网稳定性方面表现良好,有效管理微电网内的电能流动,减少电压波动。此外,讨论了基于IFWA的微电网储能双向逆变器的电路结构和控制策略,以及相关的模拟结果。
    This study aims to address optimization and operational challenges in multi-energy coupled microgrids to enhance system stability and reliability. After analyzing the requirements of such systems within comprehensive energy systems, an improved fireworks algorithm (IFWA) is proposed. This algorithm combines an adaptive resource allocation strategy with a community genetic strategy, automatically adjusting explosion range and spark quantity based on individual optimization status to meet actual needs. Additionally, a multi-objective optimization model considering active power network losses and static voltage is constructed, utilizing the shuffled frog-leaping algorithm (SFLA) to solve constrained multi-objective optimization problems. Through simulation experiments on a typical northern comprehensive energy system, conducted with a scheduling period of T = 24, the feasibility and superiority of IFWA-SFLA are validated. Results indicate that IFWA-SFLA performs well in optimizing microgrid stability, managing electrical energy flow effectively within the microgrid, and reducing voltage fluctuations. Furthermore, the circuit structure and control strategy of microgrid energy storage bidirectional inverters based on IFWA are discussed, along with relevant simulation results.
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  • 文章类型: Journal Article
    文章提出了一种使用分层环境选择策略的优化算法,以解决当前多模态多目标优化算法在获得Pareto最优集(PS)的完整性和收敛性方面的不足。首先,本文中的算法由差分进化算法(DE)框架,并使用特殊的拥挤距离来设计基于邻域的个体变异策略,这也确保了多样性,然后使用特殊的拥挤距离来帮助非主导排序的人群。在环境选择阶段,设计了一个分层选择个体的策略,根据比率逐层选择排序后的非显性排序个体,这允许潜在的个人被探索。最后,在个体进化的阶段,研究了种群的收敛性和多样性,并根据个体的特点选择不同的突变策略。DE再现策略用于迭代,防止个人避免过早收敛并确保算法的可搜索性。这些策略有助于算法获得更多样化和均匀分布的PS和ParetoFront(PF)。本文的算法在13个测试问题上与其他几种优秀算法进行了比较,测试结果表明,本文的所有算法都表现出优越的性能。
    The article proposes an optimization algorithm using a hierarchical environment selection strategyto solve the deficiencies of current multimodal multi-objective optimization algorithms in obtaining the completeness and convergence of Pareto optimal Sets (PSs). Firstly, the algorithm in this article is framed by a differential evolutionary algorithm (DE) and uses a special crowding distance to design a neighborhood-based individual variation strategy, which also ensures the diversity, and then special crowding distance is used to help populations with non-dominated sorting. In the stage of environmental selection, a strategy of hierarchical selection of individuals was designed, which selects sorted non-dominant ranked individual layer by layer according to the ratio, which allows potential individuals tobe explored. Finally, in the stage of evolution of individuals, the convergence and diversity of populations were investigated, anddifferent mutation strategies were selectedaccording to the characteristics of individuals. DE reproduction strategies are used for iteration, preventing individuals from avoiding premature convergence and ensuring the algorithm\'s searchability. These strategies help the algorithm to obtain more diverse and uniformly distributed PSs and Pareto Front (PF). The algorithm of this article compares with several other excellent algorithms on 13 test problems, and the test results show that all the algorithms of this article exhibit superior performance.
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  • 文章类型: Journal Article
    能源密集型负荷受益于低电价和碳排放,因为它们在产品的总成本中占据一定数量。本文考虑了能源密集型负荷参与电力以及碳交易来降低成本。首先,基于相关值法建立了电碳模型,根据能源密集型负荷的用电量计算其碳排放量,实现碳排放。之后,采用基线法将自由碳排放配额分配给能源密集型负荷,并提出了考虑抵消的奖罚碳交易价格机制。接下来,实现最大利益的目标函数,并减少输出波动,并提出了改善新能源住宿的建议。案例研究表明,通过比较多目标函数优化,本文提出的优化目标可以有效降低风电出力波动,提高风电消纳。通过对碳交易和电力市场收入的全面参与,多目标优化可以在减少碳排放的前提下,在保证高耗能负荷满足生产要求的同时,增加系统收益,验证了本文提出的低碳优化运营模型的有效性。
    Energy-intensive load benefits from low electricity tariff and carbon emission, since they occupy certain amounts in the total cost of the product. This paper considers energy-intensive load participation in the electricity as well as carbon trading to reduce the cost. Firstly, an electricity-carbon model is established based on the correlation value method to calculate the carbon emissions of energy-intensive load based on their electricity consumption to realize the carbon amount. Afterwards, the baseline method is used to allocate free carbon emission quotas to energy-intensive load and a reward-penalty carbon trading price mechanism considering offset is proposed. Next, the objective function to achieve maximum benefits, and to reduce output fluctuation, and to improve new energy accommodation is proposed. The case studies show that, by comparing multi-objective function optimization, the optimization target proposed in this paper can effectively reduce wind power output fluctuations and improve wind power accommodation. Through the total participation in carbon trading and electricity market income, multi-objective optimization can increase the system income while ensuring that energy-intensive load meets production requirements under the premise of reducing carbon emissions, verifying the effectiveness of the low-carbon optimal operation model proposed in this paper.
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  • 文章类型: Journal Article
    随着数字图片在医疗行业的数量和意义不断增加,图像质量评估(IQA)最近已成为研究界的普遍主题。由于磁共振图像(MRI)可以经历的各种失真以及它们包含的各种信息,无参考图像质量评估(NR-IQA)一直是一个具有挑战性的研究问题。为了解决这个问题,提出了一种新颖的混合人工智能(AI)来分析海量MRI数据中的NR-IQ。首先,使用灰度游程长度矩阵(GLRLM)和EfficientNetB7算法从去噪的MRI图像中提取特征。接下来,提出了多目标爬行动物搜索算法(MRSA)用于最优特征向量选择。然后,提出了自进化深度信念模糊神经网络(SDBFN)算法用于有效的NR-IQ分析。本研究的实现是使用MATLAB软件执行的。将模拟结果与各种常规方法在相关系数(PLCC)方面进行了比较,均方根误差(RMSE),斯皮尔曼排序相关系数(SROCC)和肯德尔排序相关系数(KROCC),和平均绝对误差(MAE)。此外,我们提出的方法产生了大约比现有方法显著提高20%的质量,与目前的技术相比,PLCC参数显示出显着的增加。此外,与现有方法相比,RMSE数减少了12%。图形表示显示MRI膝关节数据集的平均MAE值为0.02,0.09的MRI大脑数据集,和0.098的MRI乳房数据集,与基线模型相比,MAE值显着降低。
    As the quantity and significance of digital pictures in the medical industry continue to increase, Image Quality Assessment (IQA) has recently become a prevalent subject in the research community. Due to the wide range of distortions that Magnetic Resonance Images (MRI) can experience and the wide variety of information they contain, No-Reference Image Quality Assessment (NR-IQA) has always been a challenging study issue. In an attempt to address this issue, a novel hybrid Artificial Intelligence (AI) is proposed to analyze NR-IQ in massive MRI data. First, the features from the denoised MRI images are extracted using the gray level run length matrix (GLRLM) and EfficientNet B7 algorithm. Next, the Multi-Objective Reptile Search Algorithm (MRSA) was proposed for optimal feature vector selection. Then, the Self-evolving Deep Belief Fuzzy Neural network (SDBFN) algorithm was proposed for the effective NR-IQ analysis. The implementation of this research is executed using MATLAB software. The simulation results are compared with the various conventional methods in terms of correlation coefficient (PLCC), Root Mean Square Error (RMSE), Spearman Rank Order Correlation Coefficient (SROCC) and Kendall Rank Order Correlation Coefficient (KROCC), and Mean Absolute Error (MAE). In addition, our proposed approach yielded a quality number approximately we achieved significant 20% improvement than existing methods, with the PLCC parameter showing a notable increase compared to current techniques. Moreover, the RMSE number decreased by 12% when compared to existing methods. Graphical representations indicated mean MAE values of 0.02 for MRI knee dataset, 0.09 for MRI brain dataset, and 0.098 for MRI breast dataset, showcasing significantly lower MAE values compared to the baseline models.
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  • 文章类型: Journal Article
    目的:聚合物聚醚醚酮(PEEK)因其优异的机械性能而逐渐被用于牙科修复体,耐化学性,抗疲劳性,热稳定性,辐射半透明性和良好的生物相容性。为了尽快处理具有较低表面粗糙度的PEEK假牙,提出了非支配排序遗传算法-II(NSGA-II)集成遗传算法反向传播(GABP)神经网络,可以调整铣削PEEK义齿的工艺参数组合。
    方法:使用四轴牙科铣床在不同的工艺参数下进行PEEK加工。使用表面粗糙度轮廓仪和扫描电子显微镜(SEM)表征PEEK假牙的表面粗糙度。使用NSGA-II集成GABP神经网络算法的多目标优化模型研究了铣削PEEK假牙的最佳加工性能。表面粗糙度(Ra)和材料去除率(MRR)被用作优化目标。
    结果:多目标优化模型有效地提高了铣削PEEK假牙的表面粗糙度和加工效率。验证实验表明,所有PEEK义齿的表面粗糙度均小于0.2μm,在本文设定的表面粗糙度范围内。GABP表面粗糙度预测模型的平均误差为6%。对于相同的表面粗糙度值,优化后的铣削参数均具有较大的材料去除率。
    结论:研究结果可以通过使用NSGA-II集成GABP算法提供适当的铣削参数来改善当前的PEEK义齿CAD/CAM技术。
    OBJECTIVE: The polymer polyetheretherketone (PEEK) is gradually being used in dental restorations because of its excellent mechanical properties, chemical resistance, fatigue resistance, thermal stability, radiation translucency and good biocompatibility. To process PEEK dentures with lower surface roughness as quickly as possible, the non-dominated sorting genetic algorithm-II (NSGA-II) integrated genetic algorithm back propagation (GABP) neural network was proposed, which can adjust the combination of process parameters for milling PEEK dentures.
    METHODS: The PEEK machining was conducted using a four-axis dental milling machine at different process parameters. The surface roughness of PEEK dentures was characterized using surface roughness profiler and scanning electron microscopy (SEM). The optimum machining performance of milling PEEK dentures was investigated using a multi-objective optimization model named as NSGA-II integrated GABP neural network algorithm. The surface roughness (Ra) and material removal rate (MRR) were used as optimization objectives.
    RESULTS: The multi-objective optimization model effectively improved surface roughness and machining efficiency for milling PEEK dentures. The validation experiments showed that the surface roughness of all PEEK dentures was less than 0.2μm, which was within the range of surface roughness set in this paper. The GABP surface roughness prediction model had an average error of 6 %. For the same surface roughness value, the optimized milling parameters all had a greater material removal rate.
    CONCLUSIONS: The research results can improve current PEEK denture CAD/CAM technology by providing appropriate milling parameters using NSGA-II integrated GABP algorithm.
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