Heuristic optimization

  • 文章类型: Journal Article
    永磁同步电机(PMSM)的有效设计对于其运行性能至关重要。一个关键的设计参数,齿槽转矩,受电机各种结构参数的显著影响,使电机结构的优化复杂化。本文提出了一种基于启发式优化算法的永磁同步电机结构优化方法。永磁同步电机自优化提升算法(PMSM-SLA)。最初,使用有限元仿真方法创建了一个数据集,该数据集捕获了各种结构参数场景下的电机效率。在这个数据集上,引入了针对永磁同步电机结构优化的批量优化解决方案,以确定最大化电机效率的结构参数集。本研究提出的方法提高了优化永磁同步电机结构的效率,克服了传统试错法的局限性,支持PMSM结构设计的工业应用。
    The efficient design of Permanent Magnet Synchronous Motors (PMSMs) is crucial for their operational performance. A key design parameter, cogging torque, is significantly influenced by various structural parameters of the motor, complicating the optimization of motor structures. This paper proposes an optimization method for PMSM structures based on heuristic optimization algorithms, named the Permanent Magnet Synchronous Motor Self-Optimization Lift Algorithm (PMSM-SLA). Initially, a dataset capturing the efficiency of motors under various structural parameter scenarios is created using finite element simulation methods. Building on this dataset, a batch optimization solution aimed at PMSM structure optimization was introduced to identify the set of structural parameters that maximize motor efficiency. The approach presented in this study enhances the efficiency of optimizing PMSM structures, overcoming the limitations of traditional trial-and-error methods and supporting the industrial application of PMSM structural design.
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  • 文章类型: Journal Article
    近年来,我们的世界很难满足人类的需求。为了确保世界能够在自然资源方面维持其可居住性和自给自足,要求生物承载力面积总量等于或高于生态足迹。已经进行了一项分析研究,通过利用土耳其的这些信息来弥补生物容量不足,然后使用启发式优化技术对这些区域进行优化。因此,人工蜂群在最小值方面比粒子群优化和基于聚类和抛物线逼近的全局优化方法提供了更好的目标函数结果(误差更少),最大值,平均值,和标准偏差。根据2016年生物净度区现状,变化率为277.97%,30.28%,-29.28%,14.97%,农田为-44.85%,放牧的土地,林地,渔场,和建成用地。根据人口的增长,这些比率应另外变化83.24%,-0.69%,3.97%,6.22%,和2050年分别为-14.24%。开发的模型可用于工业或政府发展政策框架内,因此可以控制生态足迹和生物承载力之间的平衡。
    Our world has had difficulty meeting humans\' needs in recent years. To ensure that the world can sustain its inhabitability and self-sufficiency in terms of natural resources, it is required to make the total amount of biocapacity areas equal to or higher than the ecological footprint. An analytical study has been carried out to remedy the biocapacity deficit by utilizing this information for Turkey and then these areas are optimized with heuristic optimization techniques. As a result, Artificial Bee Colony provides better objective function results (fewer errors) compared to Particle Swarm Optimization and Global Optimization Method Based on Clustering and Parabolic Approximation in terms of minimum, maximum, average value, and standard deviation. The rates of change according to the current situation of the biocapacity areas in 2016 are 277.97 %, 30.28 %, -29.28 %, 14.97 %, and -44.85 % for cropland, grazing land, forestland, fishing grounds, and built-up land, respectively. Depending on the population growth, these rates should additionally change by 83.24 %, -0.69 %, 3.97 %, 6.22 %, and -14.24 % respectively in 2050. The developed model can be used in industry or within the frame of government development policy and thus the balance between ecological footprint and biocapacity can be kept under control.
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  • 文章类型: Journal Article
    LoRaWAN是一种长距离和低功耗协议,旨在连接物联网(IoT)范式下的设备。该协议不支持实时消息传递;因此,使用它来支持涉及大型无线传感器网络和时间约束消息传递的物联网解决方案并不总是可行的,例如,在自然灾害预警系统中,工业机械的远程监控或运输系统的自主控制。本文提出了一种提供确定性的模型,在物联网系统的设计时,关于他们的支持网络的实时通信能力。它允许解决方案设计人员:(1)根据其通信基础设施的可行性来决定是否开发实时物联网解决方案,(2)改善通信基础设施,尝试使用LoRaWAN实现实时通信。
    LoRaWAN is a long range and low power protocol devised for connecting devices under the Internet of Things (IoT) paradigm. This protocol was not conceived to support real-time message delivery; therefore, it is not always feasible using it to support IoT solutions involving large wireless sensors networks and time constraint messaging, e.g., in early warning systems for natural hazards, remote monitoring of industrial machinery or autonomous control of transportation systems. This paper presents a model that provides certainty, at the design time of IoT systems, about the real-time communication capability of their supporting network. It allows solution designers: (1) to decide if developing or not a real-time IoT solution based on the feasibility of its communication infrastructure, and (2) to improve the communication infrastructure to try making real-time communication feasible using LoRaWAN.
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  • 文章类型: Journal Article
    为了在NISQ设备上实现量子电路,它必须转换为满足设备连接限制的功能等效电路。然而,NISQ设备本质上是嘈杂的,并且最小化添加到电路的SWAP门的数量对于减少计算误差至关重要。为了实现这一点,提出了一种基于量子门时序权重优先级的子图同构算法,这为特定的二维量子架构提供了更好的初始映射。此外,我们引入了一种启发式交换序列选择优化算法,该算法使用距离优化测量函数来选择理想序列并减少SWAP门的数量,从而优化电路变换。我们的实验表明,我们提出的算法对大多数基准量子电路是有效的,最大优化率高达43.51%,平均优化率为13.51%,优于现有的相关方法。
    In order to implement a quantum circuit on an NISQ device, it must be transformed into a functionally equivalent circuit that satisfies the device\'s connectivity constraints. However, NISQ devices are inherently noisy, and minimizing the number of SWAP gates added to the circuit is crucial for reducing computation errors. To achieve this, we propose a subgraph isomorphism algorithm based on the timing weight priority of quantum gates, which provides a better initial mapping for a specific two-dimensional quantum architecture. Additionally, we introduce a heuristic swap sequence selection optimization algorithm that uses a distance optimization measurement function to select the ideal sequence and reduce the number of SWAP gates, thereby optimizing the circuit transformation. Our experiments demonstrate that our proposed algorithm is effective for most benchmark quantum circuits, with a maximum optimization rate of up to 43.51% and an average optimization rate of 13.51%, outperforming existing related methods.
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  • 文章类型: Journal Article
    在工程实践中,经常面临一个问题,其中未知参数的数量超过条件或要求的数量,否则,设计参数太少,要求太多。这种定义不足或定义过高的任务有时无法使用直接方法来解决。解决这些问题的方法有很多,并且通过数值方法搜索最优参数是最合理的,因为要设计的未知设计参数越多,潜在的解决方案越多。本文在设计飞机复合机翼蒙皮的实例的基础上,讨论了通过启发式优化方法找到这种欠定问题的最优解的方法。几种启发式方法,特别是梯度下降和禁忌搜索,进行了研究,以解决设计问题并找到最优解。还将它们与传统的直接方法进行比较。通过最小重量的目标函数以及强度和屈曲破坏准则的约束,对所检查的复合材料薄板进行了优化。在大多数观察到的情况下,启发式方法设计的结构在重量与载荷比方面比通过常规直接方法获得的结构要好得多。
    In engineering practice, a problem is quite often faced in which the number of unknown parameters exceeds the number of conditions or requirements or, otherwise, there are too many requirements for too few parameters to design. Such under- or over-defined tasks are sometimes not possible to solve using a direct approach. The number of solutions to such problems is multiple, and it is most rational to search for the optimal one by numerical methods since the more unknown design parameters there are to be designed, the more potential solutions there are. This article discusses a way to find an optimal solution to such an underdetermined problem by heuristic optimization methods on the basis of the example of designing a composite wing skin of an aircraft. Several heuristic approaches, specifically gradient descent and Tabu search, are studied to solve the design problem and to locate an optimal solution. They are also compared to a conventional direct approach. The examined composite lamina is optimized by the target function of minimum weight with the constraints of strength and buckling failure criteria. In most of the observed cases, the heuristic method designed structures which were considerably better than the structures that were obtained by conventional direct approaches in terms of the weight to load ratio.
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  • 文章类型: Journal Article
    新型冠状病毒肺炎(COVID-19)对医用口罩产生了巨大的需求,需要将其运送到许多需求点以保护公民。交付效率对于预防和控制该流行病至关重要。然而,对口罩的巨大需求和分散的大量需求点使问题变得高度复杂。此外,实际需求往往获得较晚,因此,解决方案计算和掩码交付的持续时间通常非常有限。根据我们在中国应对COVID-19的医用口罩交付的实践经验,我们提出了一种混合机器学习和启发式优化方法,它使用深度学习模型来预测每个地区的需求,安排第一级车辆预先将预测的口罩数量从仓库预先分配给区域设施,在不同地区之间重新分配需求点,以平衡预测需求与实际需求的偏差,并最终路由二级车辆,以有效地将口罩运送到每个地区的需求点。对于复杂性大大降低的需求点重新分配和两批次路由子问题,我们提出了可变邻域禁忌搜索启发式算法来有效地解决它们。在COVID-19高峰期间,该方法在中国三个特大城市的紧急口罩交付中的应用表明,与其他无需预先分配或重新分配的方法相比,该方法具有显着的性能优势。我们还讨论了关键的成功因素和经验教训,以促进我们的方法扩展到更广泛的问题。
    The novel coronavirus pneumonia (COVID-19) has created huge demands for medical masks that need to be delivered to a lot of demand points to protect citizens. The efficiency of delivery is critical to the prevention and control of the epidemic. However, the huge demands for masks and massive number of demand points scattered make the problem highly complex. Moreover, the actual demands are often obtained late, and hence the time duration for solution calculation and mask delivery is often very limited. Based on our practical experience of medical mask delivery in response to COVID-19 in China, we present a hybrid machine learning and heuristic optimization method, which uses a deep learning model to predict the demand of each region, schedules first-echelon vehicles to pre-distribute the predicted number of masks from depot(s) to regional facilities in advance, reassigns demand points among different regions to balance the deviations of predicted demands from actual demands, and finally routes second-echelon vehicles to efficiently deliver masks to the demand points in each region. For the subproblems of demand point reassignment and two-batch routing whose complexities are significantly lower, we propose variable neighborhood tabu search heuristics to efficiently solve them. Application of the proposed method in emergency mask delivery in three megacities in China during the peak of COVID-19 demonstrated its significant performance advantages over other methods without pre-distribution or reassignment. We also discuss key success factors and lessons learned to facilitate the extension of our method to a wider range of problems.
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  • 文章类型: Journal Article
    目的:快速体积超声为腹部病变的放射治疗提供了一种有趣的方式,用于连续和实时的部分内目标跟踪。然而,超声探头靠近目标结构的放置导致阻挡一些波束方向。
    方法:为了处理搜索超声机器人姿态和最佳治疗波束子集的组合复杂性,我们将基于CNN的候选波束选择与模拟退火相结合,以优化超声机器人的设置,和线性优化,将治疗计划优化转化为基于人工智能的方法。对于以前使用射波刀治疗的50例前列腺病例,我们研究了包括机器人超声引导时的设置和治疗计划优化.
    结果:基于CNN的搜索大大优于以前的随机启发式算法,平均覆盖率从93.66%增加到97.20%。此外,在某些情况下,总MU也减少了,特别是对于较小的目标体积。基于AI的优化后的结果对于有和没有超声引导的波束阻断的治疗计划是相似的。
    结论:基于AI的优化允许快速有效地搜索机器人超声引导放射治疗的配置。可以成功地减轻超声机器人对计划质量的负面影响,从而仅产生微小差异。
    OBJECTIVE: Fast volumetric ultrasound presents an interesting modality for continuous and real-time intra-fractional target tracking in radiation therapy of lesions in the abdomen. However, the placement of the ultrasound probe close to the target structures leads to blocking some beam directions.
    METHODS: To handle the combinatorial complexity of searching for the ultrasound-robot pose and the subset of optimal treatment beams, we combine CNN-based candidate beam selection with simulated annealing for setup optimization of the ultrasound robot, and linear optimization for treatment plan optimization into an AI-based approach. For 50 prostate cases previously treated with the CyberKnife, we study setup and treatment plan optimization when including robotic ultrasound guidance.
    RESULTS: The CNN-based search substantially outperforms previous randomized heuristics, increasing coverage from 93.66 to 97.20% on average. Moreover, in some cases the total MU was also reduced, particularly for smaller target volumes. Results after AI-based optimization are similar for treatment plans with and without beam blocking due to ultrasound guidance.
    CONCLUSIONS: AI-based optimization allows for fast and effective search for configurations for robotic ultrasound-guided radiation therapy. The negative impact of the ultrasound robot on the plan quality can successfully be mitigated resulting only in minor differences.
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  • 文章类型: Journal Article
    在并网微电网中,电动汽车(EV)必须有效地安排经济有效的电力消耗和网络运营。所涉及参数的随机性以及它们的大量和相关性使得这种调度成为一项具有挑战性的任务。本文旨在确定相关的创新解决方案,以降低混合微电网中并网电动汽车的相关总成本。为了最佳地扩展电动汽车,考虑了启发式贪婪方法。与文献中大多数现有的调度方法不同,所提出的贪婪调度程序是无模型的,免费培训,但高效。拟议的方法考虑了不同的因素,如电价、并网电动汽车的到达和离开状态,和总收入,以满足负载需求。基于贪婪的方法在实现混合微电网系统的目标方面表现令人满意,这是建立在光伏上的,风力涡轮机,和当地的公用电网。同时,并网电动汽车被用作储能交换位置。全面进行实时硬件在环实验,以最大化获得的利润。通过不同的不确定性场景,评估了所提出的贪婪方法获得全局最优解的能力。开发了一个数据模拟器,用于生成评估数据集,它捕获了系统参数行为中的不确定性。基于贪婪的策略被认为是适用的,可扩展,并在总运营支出方面高效。此外,随着电动汽车的渗透变得更加通用,总费用大幅下降。使用有效运行持续时间为500年的模拟数据,拟议的方法成功地将能源消耗成本降低了约50-85%,击败现有的最新成果。所提出的方法被证明可以容忍系统运行数据中涉及的大量不确定性。
    In on-grid microgrids, electric vehicles (EVs) have to be efficiently scheduled for cost-effective electricity consumption and network operation. The stochastic nature of the involved parameters along with their large number and correlations make such scheduling a challenging task. This paper aims at identifying pertinent innovative solutions for reducing the relevant total costs of the on-grid EVs within hybrid microgrids. To optimally scale the EVs, a heuristic greedy approach is considered. Unlike most existing scheduling methodologies in the literature, the proposed greedy scheduler is model-free, training-free, and yet efficient. The proposed approach considers different factors such as the electricity price, on-grid EVs state of arrival and departure, and the total revenue to meet the load demands. The greedy-based approach behaves satisfactorily in terms of fulfilling its objective for the hybrid microgrid system, which is established of photovoltaic, wind turbine, and a local utility grid. Meanwhile, the on-grid EVs are being utilized as an energy storage exchange location. A real time hardware-in-the-loop experimentation is comprehensively conducted to maximize the earned profit. Through different uncertainty scenarios, the ability of the proposed greedy approach to obtain a global optimal solution is assessed. A data simulator was developed for the purposes of generating evaluation datasets, which captures uncertainties in the behaviors of the system\'s parameters. The greedy-based strategy is considered applicable, scalable, and efficient in terms of total operating expenditures. Furthermore, as EVs penetration became more versatile, total expenses decreased significantly. Using simulated data of an effective operational duration of 500 years, the proposed approach succeeded in cutting down the energy consumption costs by about 50-85%, beating existing state-of-the-arts results. The proposed approach is proved to be tolerant to the large amounts of uncertainties that are involved in the system\'s operational data.
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  • 文章类型: Journal Article
    OBJECTIVE: Robotic ultrasound promises continuous, volumetric, and non-ionizing tracking of organ motion during radiation therapy. However, placement of the robot is critical because it is radio-opaque and might severely influence the achievable dose distribution.
    METHODS: We propose two heuristic optimization strategies for automatic placement of an ultrasound robot around a patient. Considering a kinematically redundant robot arm, we compare a generic approach based on stochastic search and a more problem-specific segmentwise construction approach. The former allows for multiple elbow configurations while the latter is deterministic. Additionally, we study different objective functions guiding the search. Our evaluation is based on data for ten actual prostate cancer cases and we compare the resulting plan quality for both methods to manually chosen robot configurations previously proposed.
    RESULTS: The mean improvements in the treatment planning objective value with respect to the best manually selected robot position and a single elbow configuration range from 8.2 to 32.8% and 8.5 to 15.5% for segmentwise construction and stochastic search, respectively. Considering three different elbow configurations, the stochastic search results in better objective values in 80% of the cases, with 30% being significantly better. The optimization strategies are robust with respect to beam sampling and transducer orientation and using previous optimization results as starting point for stochastic search typically results in better solutions compared to random starting points.
    CONCLUSIONS: We propose a robust and generic optimization scheme, which can be used to optimize the robot placement for robotic ultrasound guidance in radiation therapy. The automatic optimization further mitigates the impact of robotic ultrasound on the treatment plan quality.
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  • 文章类型: Journal Article
    The accelerated movement of people towards cities led to the fact that the world\'s urban population is now growing by 60-million persons per year. The increased number of cities\' population has a significant impact on the produced volume of household waste, which must be collected and recycled in time. The collection of household waste, especially in downtown areas, has a wide range of challenges; the collection system must be reliable, flexible, cost efficient, and green. Within the frame of this paper, the authors describe the application possibilities of Industry 4.0 technologies in waste collection solutions and the optimization potential in their processes. After a systematic literature review, this paper introduces the waste collection process of downtowns as a cyber-physical system. A mathematical model of this waste collection process is described, which incorporates routing, assignment, and scheduling problems. The objectives of the model are the followings: (1) optimal assignment of waste sources to garbage trucks; (2) scheduling of the waste collection through routing of each garbage truck to minimize the total operation cost, increase reliability while comprehensive environmental indicators that have great impact on public health are to be taken into consideration. Next, a binary bat algorithm is described, whose performance is validated with different benchmark functions. The scenario analysis validates the model and then evaluates its performance to increase the cost-efficiency and warrant environmental awareness of waste collection process.
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