多阶段随机线性问题(MSLP)的解决方案代表了许多应用程序的挑战。长期水热调度计划(LHDP)在影响全球电力市场,经济和自然资源的现实世界中实现了这一挑战。没有用于MSLP的封闭式解决方案,并且具有高质量的非预期策略的定义是至关重要的。线性决策规则(LDR)提供了一个有趣的基于模拟的框架,可通过两阶段随机模型为MSLP找到高质量的策略。但是,在实际应用中,使用LDR时要估计的参数数量可能接近或高于样本平均近似问题的场景数量,从而在样本外产生样本外的过度效果和差的表现不佳模拟。在本文中,我们提出了一个新型的正则LDR来基于Adalasso(自适应最少的绝对收缩和选择算子)求解MSLP。目的是使用高维线性回归模型中所研究的简约原理,以获得应用于MSLP的LDR的更好的样本外部性能。计算实验表明,使用经典的非规范LDR来求解LHDP时,过度合适的威胁是不可忽略的,这是研究最多的MSLP之一,其中具有相关应用在行业中。我们的分析强调了拟议框架与非规范化基准相比的以下好处:1)非零系数的数量显着减少(模型简约),2)2)大幅度降低样本外评估的成本降低, 3)改善了现货价格概况。
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Ongoing risks from climate change have impacted the livelihood of global nomadic communities, and are likely to lead to increased migratory movements in coming years. As a result, mobility considerations are becoming increasingly important in energy systems planning, particularly to achieve energy access in developing countries. Advanced Plug and Play control strategies have been recently developed with such a decentralized framework in mind, more easily allowing for the interconnection of nomadic communities, both to each other and to the main grid. In light of the above, the design and planning strategy of a mobile multi-energy supply system for a nomadic community is investigated in this work. Motivated by the scale and dimensionality of the associated uncertainties, impacting all major design and decision variables over the 30-year planning horizon, Deep Reinforcement Learning (DRL) is implemented for the design and planning problem tackled. DRL based solutions are benchmarked against several rigid baseline design options to compare expected performance under uncertainty. The results on a case study for ger communities in Mongolia suggest that mobile nomadic energy systems can be both technically and economically feasible, particularly when considering flexibility, although the degree of spatial dispersion among households is an important limiting factor. Key economic, sustainability and resilience indicators such as Cost, Equivalent Emissions and Total Unmet Load are measured, suggesting potential improvements compared to available baselines of up to 25%, 67% and 76%, respectively. Finally, the decomposition of values of flexibility and plug and play operation is presented using a variation of real options theory, with important implications for both nomadic communities and policymakers focused on enabling their energy access.
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Decision-making problems are commonly formulated as optimization problems, which are then solved to make optimal decisions. In this work, we consider the inverse problem where we use prior decision data to uncover the underlying decision-making process in the form of a mathematical optimization model. This statistical learning problem is referred to as data-driven inverse optimization. We focus on problems where the underlying decision-making process is modeled as a convex optimization problem whose parameters are unknown. We formulate the inverse optimization problem as a bilevel program and propose an efficient block coordinate descent-based algorithm to solve large problem instances. Numerical experiments on synthetic datasets demonstrate the computational advantage of our method compared to standard commercial solvers. Moreover, the real-world utility of the proposed approach is highlighted through two realistic case studies in which we consider estimating risk preferences and learning local constraint parameters of agents in a multiplayer Nash bargaining game.
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本文在线学习和优化框架内提出并开发了一种用于电力市场中风能交易的新算法。特别是,我们将梯度下降算法的组成部分自适应变体与功能驱动的新闻册模型的最新进展相结合。这导致了一种在线产品的方法,能够利用数据丰富的环境,同时适应能源发电和发电市场的非平稳特征,并且具有最小的计算负担。根据几个数值实验,对我们的方法的性能进行了分析,既显示了对非平稳性不确定参数的更好适应性和显着的经济增长。
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增强现有传输线是对抗传输拥塞并保证传输安全性随需求增加并增强可再生能源的有用工具。这项研究涉及选择其容量应扩大的线路的选择,以及从独立系统操作员(ISO)的角度来看,通过考虑传输线约束以及发电和需求平衡条件,并结合坡道 - 上升和启动坡道率,关闭坡道速率,坡度降低率限制以及最小降低时间。为此,我们开发了ISO单元承诺和经济调度模型,并将其作为混合整数线性编程(MILP)问题的右侧不确定性多个参数分析。我们首先放松二进制变量,以连续变量并采用拉格朗日方法和Karush-Kuhn-Tucker条件,以获得最佳的解决方案(最佳决策变量和目标函数)以及与主动和无效约束相关的关键区域。此外,我们通过确定每个节点处的问题上限,然后比较上限和下限之间的差异,并在决策制造商中达到近似最佳解决方案,从而扩展传统分支和界限方法,以解决大规模MILP问题。可耐受的误差范围。另外,目标函数在每行参数上的第一个衍生物用于告知各行的选择,以简化拥塞和最大化社会福利。最后,通过平衡目标函数的成本率和阵容升级成本来选择容量升级的量。我们的发现得到了数值模拟的支持,并为传输线计划提供了决策指导。
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As various city agencies and mobility operators navigate toward innovative mobility solutions, there is a need for strategic flexibility in well-timed investment decisions in the design and timing of mobility service regions, i.e. cast as "real options" (RO). This problem becomes increasingly challenging with multiple interacting RO in such investments. We propose a scalable machine learning based RO framework for multi-period sequential service region design & timing problem for mobility-on-demand services, framed as a Markov decision process with non-stationary stochastic variables. A value function approximation policy from literature uses multi-option least squares Monte Carlo simulation to get a policy value for a set of interdependent investment decisions as deferral options (CR policy). The goal is to determine the optimal selection and timing of a set of zones to include in a service region. However, prior work required explicit enumeration of all possible sequences of investments. To address the combinatorial complexity of such enumeration, we propose a new variant "deep" RO policy using an efficient recurrent neural network (RNN) based ML method (CR-RNN policy) to sample sequences to forego the need for enumeration, making network design & timing policy tractable for large scale implementation. Experiments on multiple service region scenarios in New York City (NYC) shows the proposed policy substantially reduces the overall computational cost (time reduction for RO evaluation of > 90% of total investment sequences is achieved), with zero to near-zero gap compared to the benchmark. A case study of sequential service region design for expansion of MoD services in Brooklyn, NYC show that using the CR-RNN policy to determine optimal RO investment strategy yields a similar performance (0.5% within CR policy value) with significantly reduced computation time (about 5.4 times faster).
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许多实际优化问题涉及不确定的参数,这些参数具有概率分布,可以使用上下文特征信息来估算。与首先估计不确定参数的分布然后基于估计优化目标的标准方法相反,我们提出了一个\ textIt {集成条件估计 - 优化}(ICEO)框架,该框架估计了随机参数的潜在条件分布同时考虑优化问题的结构。我们将随机参数的条件分布与上下文特征之间的关系直接建模,然后以与下游优化问题对齐的目标估算概率模型。我们表明,我们的ICEO方法在适度的规律性条件下渐近一致,并以概括范围的形式提供有限的性能保证。在计算上,使用ICEO方法执行估计是一种非凸面且通常是非差异的优化问题。我们提出了一种通用方法,用于近似从估计的条件分布到通过可区分函数的最佳决策的潜在非差异映射,这极大地改善了应用于非凸问题的基于梯度的算法的性能。我们还提供了半代理案例中的多项式优化解决方案方法。还进行了数值实验,以显示我们在不同情况下的方法的经验成功,包括数据样本和模型不匹配。
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Uncertainty is prevalent in engineering design, statistical learning, and decision making broadly. Due to inherent risk-averseness and ambiguity about assumptions, it is common to address uncertainty by formulating and solving conservative optimization models expressed using measure of risk and related concepts. We survey the rapid development of risk measures over the last quarter century. From its beginning in financial engineering, we recount their spread to nearly all areas of engineering and applied mathematics. Solidly rooted in convex analysis, risk measures furnish a general framework for handling uncertainty with significant computational and theoretical advantages. We describe the key facts, list several concrete algorithms, and provide an extensive list of references for further reading. The survey recalls connections with utility theory and distributionally robust optimization, points to emerging applications areas such as fair machine learning, and defines measures of reliability.
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由于数据量增加,金融业的快速变化已经彻底改变了数据处理和数据分析的技术,并带来了新的理论和计算挑战。与古典随机控制理论和解决财务决策问题的其他分析方法相比,解决模型假设的财务决策问题,强化学习(RL)的新发展能够充分利用具有更少模型假设的大量财务数据并改善复杂的金融环境中的决策。该调查纸目的旨在审查最近的资金途径的发展和使用RL方法。我们介绍了马尔可夫决策过程,这是许多常用的RL方法的设置。然后引入各种算法,重点介绍不需要任何模型假设的基于价值和基于策略的方法。连接是用神经网络进行的,以扩展框架以包含深的RL算法。我们的调查通过讨论了这些RL算法在金融中各种决策问题中的应用,包括最佳执行,投资组合优化,期权定价和对冲,市场制作,智能订单路由和Robo-Awaring。
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Algorithms that involve both forecasting and optimization are at the core of solutions to many difficult real-world problems, such as in supply chains (inventory optimization), traffic, and in the transition towards carbon-free energy generation in battery/load/production scheduling in sustainable energy systems. Typically, in these scenarios we want to solve an optimization problem that depends on unknown future values, which therefore need to be forecast. As both forecasting and optimization are difficult problems in their own right, relatively few research has been done in this area. This paper presents the findings of the ``IEEE-CIS Technical Challenge on Predict+Optimize for Renewable Energy Scheduling," held in 2021. We present a comparison and evaluation of the seven highest-ranked solutions in the competition, to provide researchers with a benchmark problem and to establish the state of the art for this benchmark, with the aim to foster and facilitate research in this area. The competition used data from the Monash Microgrid, as well as weather data and energy market data. It then focused on two main challenges: forecasting renewable energy production and demand, and obtaining an optimal schedule for the activities (lectures) and on-site batteries that lead to the lowest cost of energy. The most accurate forecasts were obtained by gradient-boosted tree and random forest models, and optimization was mostly performed using mixed integer linear and quadratic programming. The winning method predicted different scenarios and optimized over all scenarios jointly using a sample average approximation method.
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预测组合在预测社区中蓬勃发展,近年来,已经成为预测研究和活动主流的一部分。现在,由单个(目标)系列产生的多个预测组合通过整合来自不同来源收集的信息,从而提高准确性,从而减轻了识别单个“最佳”预测的风险。组合方案已从没有估计的简单组合方法演变为涉及时间变化的权重,非线性组合,组件之间的相关性和交叉学习的复杂方法。它们包括结合点预测和结合概率预测。本文提供了有关预测组合的广泛文献的最新评论,并参考可用的开源软件实施。我们讨论了各种方法的潜在和局限性,并突出了这些思想如何随着时间的推移而发展。还调查了有关预测组合实用性的一些重要问题。最后,我们以当前的研究差距和未来研究的潜在见解得出结论。
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作为行业4.0时代的一项新兴技术,数字双胞胎因其承诺进一步优化流程设计,质量控制,健康监测,决策和政策制定等,通过全面对物理世界进行建模,以进一步优化流程设计,质量控制,健康监测,决策和政策,因此获得了前所未有的关注。互连的数字模型。在一系列两部分的论文中,我们研究了不同建模技术,孪生启用技术以及数字双胞胎常用的不确定性量化和优化方法的基本作用。第二篇论文介绍了数字双胞胎的关键启示技术的文献综述,重点是不确定性量化,优化方法,开源数据集和工具,主要发现,挑战和未来方向。讨论的重点是当前的不确定性量化和优化方法,以及如何在数字双胞胎的不同维度中应用它们。此外,本文介绍了一个案例研究,其中构建和测试了电池数字双胞胎,以说明在这两部分评论中回顾的一些建模和孪生方法。 GITHUB上可以找到用于生成案例研究中所有结果和数字的代码和预处理数据。
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评估能源转型和能源市场自由化对资源充足性的影响是一种越来越重要和苛刻的任务。能量系统的上升复杂性需要足够的能量系统建模方法,从而提高计算要求。此外,随着复杂性,同样调用概率评估和场景分析同样增加不确定性。为了充分和高效地解决这些各种要求,需要来自数据科学领域的新方法来加速当前方法。通过我们的系统文献综述,我们希望缩小三个学科之间的差距(1)电力供应安全性评估,(2)人工智能和(3)实验设计。为此,我们对所选应用领域进行大规模的定量审查,并制作彼此不同学科的合成。在其他发现之外,我们使用基于AI的方法和应用程序的AI方法和应用来确定电力供应模型的复杂安全性的元素,并作为未充分涵盖的应用领域的储存调度和(非)可用性。我们结束了推出了一种新的方法管道,以便在评估电力供应安全评估时充分有效地解决当前和即将到来的挑战。
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我们研究了基于功能的新闻企业问题,其中决策者可以访问包括需求观察和外源特征组成的历史数据。在这种情况下,我们研究了功能选择,旨在得出具有改进样本外部性能的稀疏,可解释的模型。到目前为止,最新的方法利用正则化,这会惩罚所选特征的数量或解决方案向量的规范。作为替代方案,我们介绍了一种新型的双层编程公式。高级问题选择了一部分功能,这些功能将基于固定验证集的订购决策的样本外成本估算最小化。下层问题仅使用上层选择的功能,了解训练集中决策功能的最佳系数。我们为Bilevel程序提供了混合整数线性程序重新制定,可以通过标准优化求解器求解为最佳性。我们的计算实验表明,该方法准确地恢复了几百个观察结果的实例中的基础真相。相反,基于正则化的技术通常在功能恢复时失败,或者需要数千个观察值才能获得相似的准确性。关于样本外的概括,我们实现了改进或可比的成本绩效。
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在这项研究中,我们提出了一个深入的学习优化框架,以解决动态的混合企业计划。具体而言,我们开发了双向长期内存(LSTM)框架,可以及时向前和向后处理信息,以学习最佳解决方案,以解决顺序决策问题。我们展示了我们在预测单项电容批号问题(CLSP)的最佳决策方面的方法,其中二进制变量表示是否在一个时期内产生。由于问题的动态性质,可以将CLSP视为序列标记任务,在该任务中,复发性神经网络可以捕获问题的时间动力学。计算结果表明,我们的LSTM优化(LSTM-OPT)框架大大减少了基准CLSP问题的解决方案时间,而没有太大的可行性和最佳性。例如,对于240,000多个测试实例,在85 \%级别的预测平均将CPLEX溶液的时间减少了9倍,最佳差距小于0.05 \%\%和0.4 \%\%\%\%\%的不可行性。此外,使用较短的计划范围训练的模型可以成功预测具有更长计划范围的实例的最佳解决方案。对于最困难的数据集,LSTM在25 \%级别的LSTM预测将70 CPU小时的溶液时间降低至小于2 CPU分钟,最佳差距为0.8 \%,而没有任何不可行。 LSTM-OPT框架在解决方案质量和精确方法方面,诸如Logistic回归和随机森林之类的经典ML算法(例如($ \ ell $,s)和基于动态编程的不平等,解决方案时间的改进。我们的机器学习方法可能有益于解决类似于CLSP的顺序决策问题,CLSP需要重复,经常和快速地解决。
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Machine learning frameworks such as Genetic Programming (GP) and Reinforcement Learning (RL) are gaining popularity in flow control. This work presents a comparative analysis of the two, bench-marking some of their most representative algorithms against global optimization techniques such as Bayesian Optimization (BO) and Lipschitz global optimization (LIPO). First, we review the general framework of the model-free control problem, bringing together all methods as black-box optimization problems. Then, we test the control algorithms on three test cases. These are (1) the stabilization of a nonlinear dynamical system featuring frequency cross-talk, (2) the wave cancellation from a Burgers' flow and (3) the drag reduction in a cylinder wake flow. We present a comprehensive comparison to illustrate their differences in exploration versus exploitation and their balance between `model capacity' in the control law definition versus `required complexity'. We believe that such a comparison paves the way toward the hybridization of the various methods, and we offer some perspective on their future development in the literature on flow control problems.
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解决研究文献中的多级随机编程问题的最常见方法是使用价值函数(“动态编程”)或场景树(“随机编程”),以近似现在决定的影响。相比之下,普通行业实践是利用更容易理解和解决的未来的确定性近似,但这因忽略不确定性而受到批评。我们表明,确定性优化模型的参数化版本可以是处理不确定性而无需随机编程或动态编程的复杂性的有效方式。我们介绍了参数化确定性优化模型,特别是一个确定性的Lookead模型,作为许多复杂的随机决策问题的强大策略。该方法可以处理复杂的高维状态变量,避免与场景树或值函数近似相关联的通常近似。相反,它介绍了设计和调整参数化的离线挑战。我们通过使用一系列应用程序设置来说明了这个想法,并展示其在具有滚动预测的非标准能量存储问题中的使用。
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在过去的十年中,由于分散控制应用程序的趋势和网络物理系统应用的出现,网络控制系统在过去十年中引起了广泛的关注。但是,由于无线网络的复杂性质,现实世界中无线网络控制系统的通信带宽,可靠性问题以及对网络动态的认识不足。将机器学习和事件触发的控制结合起来有可能减轻其中一些问题。例如,可以使用机器学习来克服缺乏网络模型的问题,通过学习系统行为或通过不断学习模型动态来适应动态变化的模型。事件触发的控制可以通过仅在必要时或可用资源时传输控制信息来帮助保护通信带宽。本文的目的是对有关机器学习的使用与事件触发的控制的使用进行综述。机器学习技术,例如统计学习,神经网络和基于强化的学习方法,例如深入强化学习,并结合事件触发的控制。我们讨论如何根据机器学习使用的目的将这些学习算法用于不同的应用程序。在对文献的审查和讨论之后,我们重点介绍了与基于机器学习的事件触发的控制并提出潜在解决方案相关的开放研究问题和挑战。
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Structural Health Monitoring (SHM) describes a process for inferring quantifiable metrics of structural condition, which can serve as input to support decisions on the operation and maintenance of infrastructure assets. Given the long lifespan of critical structures, this problem can be cast as a sequential decision making problem over prescribed horizons. Partially Observable Markov Decision Processes (POMDPs) offer a formal framework to solve the underlying optimal planning task. However, two issues can undermine the POMDP solutions. Firstly, the need for a model that can adequately describe the evolution of the structural condition under deterioration or corrective actions and, secondly, the non-trivial task of recovery of the observation process parameters from available monitoring data. Despite these potential challenges, the adopted POMDP models do not typically account for uncertainty on model parameters, leading to solutions which can be unrealistically confident. In this work, we address both key issues. We present a framework to estimate POMDP transition and observation model parameters directly from available data, via Markov Chain Monte Carlo (MCMC) sampling of a Hidden Markov Model (HMM) conditioned on actions. The MCMC inference estimates distributions of the involved model parameters. We then form and solve the POMDP problem by exploiting the inferred distributions, to derive solutions that are robust to model uncertainty. We successfully apply our approach on maintenance planning for railway track assets on the basis of a "fractal value" indicator, which is computed from actual railway monitoring data.
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当我们对优化模型中的不确定参数进行观察以及对协变量的同时观察时,我们研究了数据驱动决策的优化。鉴于新的协变量观察,目标是选择一个决定以此观察为条件的预期成本的决定。我们研究了三个数据驱动的框架,这些框架将机器学习预测模型集成在随机编程样本平均值近似(SAA)中,以近似解决该问题的解决方案。 SAA框架中的两个是新的,并使用了场景生成的剩余预测模型的样本外残差。我们研究的框架是灵活的,并且可以容纳参数,非参数和半参数回归技术。我们在数据生成过程,预测模型和随机程序中得出条件,在这些程序下,这些数据驱动的SaaS的解决方案是一致且渐近最佳的,并且还得出了收敛速率和有限的样本保证。计算实验验证了我们的理论结果,证明了我们数据驱动的公式比现有方法的潜在优势(即使预测模型被误解了),并说明了我们在有限的数据制度中新的数据驱动配方的好处。
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