Many e-commerce marketplaces offer their users fast delivery options for free to meet the increasing needs of users, imposing an excessive burden on city logistics. Therefore, understanding e-commerce users' preference for delivery options is a key to designing logistics policies. To this end, this study designs a stated choice survey in which respondents are faced with choice tasks among different delivery options and time slots, which was completed by 4,062 users from the three major metropolitan areas in Japan. To analyze the data, mixed logit models capturing taste heterogeneity as well as flexible substitution patterns have been estimated. The model estimation results indicate that delivery attributes including fee, time, and time slot size are significant determinants of the delivery option choices. Associations between users' preferences and socio-demographic characteristics, such as age, gender, teleworking frequency and the presence of a delivery box, were also suggested. Moreover, we analyzed two willingness-to-pay measures for delivery, namely, the value of delivery time savings (VODT) and the value of time slot shortening (VOTS), and applied a non-semiparametric approach to estimate their distributions in a data-oriented manner. Although VODT has a large heterogeneity among respondents, the estimated median VODT is 25.6 JPY/day, implying that more than half of the respondents would wait an additional day if the delivery fee were increased by only 26 JPY, that is, they do not necessarily need a fast delivery option but often request it when cheap or almost free. Moreover, VOTS was found to be low, distributed with the median of 5.0 JPY/hour; that is, users do not highly value the reduction in time slot size in monetary terms. These findings on e-commerce users' preferences can help in designing levels of service for last-mile delivery to significantly improve its efficiency.
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关于日益增长的直播媒介的一种普遍信念是,其价值在于其“实时”组成部分。我们通过比较实时事件需求的价格弹性如何在直播中和之后的生活中进行了比较,从而研究了这种信念。我们使用来自大型直播平台的独特且丰富的数据来做到这一点,该数据使消费者可以在流中期后购买录制版本的直播版本。在我们背景下的一个挑战是,存在高维混杂因素,其与治疗政策(即价格)和兴趣结果(即需求)的关系是复杂的,并且仅部分知道。我们通过使用广义正交随机森林框架来解决这一挑战,以进行异质治疗效果估计。我们发现在整个事件生命周期中,需求价格弹性的时间弹性都显着。具体而言,随着时间的流逝,需求变得越来越敏感,直到直播一天,那天就变成了无弹性。在生活后的时期,对录制版本的需求仍然对价格敏感,但远低于在播放前的时期。我们进一步表明,价格弹性的这种时间变化是由此类事件固有的质量不确定性以及在直播过程中与内容创建者进行实时互动的机会所驱动的。
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网络形成的研究在经济学,社会学和许多其他领域都普遍存在。在本文中,我们将网络形成建模为网络中节点以连接其他节点的“选择”。我们使用离散选择模型研究这些“选择”,其中代理在两个或多个离散的替代方案之间选择。我们采用“重复选择”(RC)模型来研究网络形成。我们认为RC模型克服了多项式logit(MNL)模型的重要局限性,该模型为研究网络形成提供了一个框架,并且非常适合研究网络形成。我们还说明了如何使用RC模型使用合成和现实世界网络准确研究网络形成。使用合成网络,我们还比较了MNL模型和RC模型的性能。我们发现RC模型比MNL模型更准确地估算合成网络的数据生成过程。我们对一个定性有趣的方案进行了案例研究 - 新专利更有可能引用较旧,更被引用和类似专利的事实 - RC模型使我们能够获得有趣的见解。
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离散选择模型(DCM)需要先验了解实用程序功能,尤其是在个人之间的味道如何变化。公用事业错误指定可能会导致估计偏差,解释不准确和可预测性有限。在本文中,我们利用神经网络来学习味觉表示。我们的公式由两个模块组成:一个神经网络(味觉),该模块将口味参数(例如时间系数)作为个体特征的灵活函数;以及具有用专家知识定义的实用程序函数的多项式logit(MNL)模型。神经网络学到的口味参数被馈送到选择模型中,并将两个模块链接起来。我们的方法通过允许神经网络学习个体特征和替代属性之间的相互作用来扩展L-MNL模型(Sifringer等,2020)。此外,我们正式化并加强了可解释性条件 - 需要对分类级别的行为指标(例如,时间值,弹性)进行现实估计,这对于模型对于场景分析和政策决策至关重要。通过唯一的网络体系结构和参数转换,我们合并了先验知识,并指导神经网络在分类级别输出现实的行为指标。我们表明,TasteNet-MNL达到了基础真相模型的可预测性,并在合成数据上恢复了非线性味觉功能。它在个人层面上的估计值和选择弹性接近地面真相。在公开可用的瑞士梅特罗数据集中,TasteNet-MNL优于基准MNL和混合Logit模型的可预测性。它学习了人群中各种各样的味道变化,并提出了更高的平均值。
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Based on administrative data of unemployed in Belgium, we estimate the labour market effects of three training programmes at various aggregation levels using Modified Causal Forests, a causal machine learning estimator. While all programmes have positive effects after the lock-in period, we find substantial heterogeneity across programmes and unemployed. Simulations show that 'black-box' rules that reassign unemployed to programmes that maximise estimated individual gains can considerably improve effectiveness: up to 20 percent more (less) time spent in (un)employment within a 30 months window. A shallow policy tree delivers a simple rule that realizes about 70 percent of this gain.
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19009年的大流行急剧催化了电子购物者的扩散。电子购物的急剧增长无疑会对旅行需求产生重大影响。结果,运输建模者对电子购物需求建模的能力变得越来越重要。这项研究开发了预测家庭每周送货频率的模型。我们使用经典计量经济学和机器学习技术来获得最佳模型。发现社会经济因素,例如拥有在线杂货会员资格,家庭成员的平均年龄,男性家庭成员的百分比,家庭中的工人数量以及各种土地使用因素会影响房屋送货的需求。这项研究还比较了机器学习模型和经典计量经济学模型的解释和表现。在通过机器学习和计量经济学模型确定的变量效果中找到了一致性。但是,具有相似的召回精度,有序的概率模型是一个经典的计量经济学模型,可以准确预测家庭交付需求的总分布。相反,两个机器学习模型都无法匹配观察到的分布。
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我们根据机器学习,即人工智能的子场,折扣对瑞士联邦铁路发行的火车票的需求影响。考虑到基于调查的超级票的买家样本,我们调查了哪些客户或旅行相关的特征(包括折现率)预测购买行为,即:预订旅行,否则未通过火车实现,而不是第二次购买 - 售票或重新安排旅行时(例如,远离高峰时间),当时被提供超级票时。预测机器学习表明,客户的年龄,与特定连接的需求相关信息(例如出发时间和利用率)以及折现水平允许在一定程度上预测购买行为。此外,我们使用因果机学习来评估折现率对重新安排旅行的影响,这似乎是根据高峰时间的容量限制而相关的。假设(i)折现率是基于我们丰富的特征的准随机,(ii)购买决策以折现率单调较弱,我们确定了“始终购买者”的折现率的效果,谁会旅行。即使没有折扣,也要根据我们的调查,该调查在没有折扣的情况下询问客户行为。我们发现,平均而言,将折现率提高一个百分点会使重新安排的旅行的份额增加0.16个百分点,但总是买家。研究效果的异质性在观察物中的异质性表明,在控制其他几个特征时,休闲旅行者以及高峰时段的效果较高。
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我们研究了通过中等数量的成对比较查询引发决策者偏好的问题,以使它们成为特定问题的高质量推荐。我们受到高赌场域中的应用程序的推动,例如选择分配稀缺资源的政策以满足基本需求(例如,用于移植或住房的肾脏,因为那些经历无家可归者),其中需要由(部分)提出引出的偏好。我们在基于偏好的偏好中模拟不确定性,并调查两个设置:a)脱机偏出设置,其中所有查询都是一次,b)在线诱因设置,其中按时间顺序选择查询。我们提出了这些问题的强大优化制剂,这些问题集成了偏好诱导和推荐阶段,其目的是最大化最坏情况的效用或最小化最坏情况的后悔,并研究其复杂性。对于离线案例,在活动偏好诱导与决策信息发现的两个半阶段的稳健优化问题的形式中,我们提供了我们通过列解决的混合二进制线性程序的形式提供了等效的重构。 -Constraint生成。对于在线设置,主动偏好学习采用多级强大优化问题的形式与决策依赖的信息发现,我们提出了一种保守的解决方案方法。合成数据的数值研究表明,我们的方法在最坏情况级别,后悔和效用方面从文献中倾斜最先进的方法。我们展示了我们的方法论如何用于协助无家可归的服务机构选择分配不同类型的稀缺住房资源的政策,以遇到无家可归者。
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尽管递归logit(RL)模型最近很受欢迎,并且导致了许多应用和扩展,但关于价值函数计算的重要数值问题仍未解决。对于模型估计,此问题尤其重要,在此期间,参数会更新每个迭代,并可能违反模型可行条件。为了解决模型估计中值函数的数值问题,本研究对Oyama和Hato(2019)提出的Prism受限的RL(Prism-RL)模型进行了广泛的分析,该模型的路径集受Prism的约束。根据状态扩展的网络表示定义。数值实验已显示出参数估计的Prism-RL模型的两个重要属性。首先,即使在无法估算原始RL模型的情况下,基于PRISM的方法都可以进行稳定的估计。我们还成功地捕获了街道绿色对行人路线选择的积极影响。其次,通过隐式限制大型绕道或许多循环的路径,PRISM-RL模型比RL模型获得了更高的拟合和预测性能优点。定义基于棱镜的路径以数据为导向的方式,我们证明了描述更现实的路线选择行为的Prism-RL模型的可能性。稳定地捕获正网络属性的同时保留路径替代方案的多样性可显着扩展RL模型的实际适用性。
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我们应用因果机学习算法来评估营销干预措施的因果影响,即优惠券活动,对零售商的销售。除了评估不同类型的优惠券的平均影响外,我们还调查了不同客户群的因果关系效应的异质性,例如,在相对较高的客户与先前购买相对较高的客户之间。最后,我们使用最佳政策学习来确定(以数据驱动方式)哪些客户群应针对优惠券活动,以最大程度地提高营销干预措施在销售方面的有效性。我们发现,在检查的五个优惠券类别中,只有两个,即适用于药店产品和其他食品产品类别的优惠券,对零售商销售具有统计学上的显着积极影响。对小组平均治疗效果的评估表明,在商店的先前购买中定义的客户群中,优惠券提供的影响有很大的差异,药品店优惠券在先前购买较高的客户和其他食品优惠券中特别有效先前购买较低的客户。我们的研究提供了一种用例,用于在业务分析中应用因果机学习,以评估特定公司政策(例如营销活动)对决策支持的因果影响。
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推荐系统是帮助用户以个性化方式找到信息过载的兴趣项目,使用关于各用户的需求和偏好的知识。在会话推荐方法中,这些需求和偏好由系统中的交互式多匝对话框中的。文献中的一种常见方法来驱动这些对话框是逐步向用户逐步询问他们关于期望和不期望的项目特征或关于单个项目的偏好。在这种情况下,在该上下文中的核心研究目标是效率,在找到令人满意的项目之前对所需交互的数量进行评估。这通常是通过对向用户询问的最佳下一个问题的推断来实现。如今,对对话效率的研究几乎完全是经验的,旨在说明,例如,选择问题的一个策略优于给定的应用程序中的另一个策略。通过这项工作,我们将实证研究补充了理论,域名的对话建议的独立模型。该模型旨在涵盖一系列应用方案,使我们能够以正式的方式调查会话方法的效率,特别是关于设计最佳相互作用策略的计算复杂性。通过如此理论分析,我们表明,找到高效的会话策略是NP - 硬,并且在PSPace中,但对于特定类型的目录,上限降低到Polylogspace。从实际的角度来看,该结果意味着目录特征可以强烈影响个人对话策略的效率,因此在设计新策略时应考虑。从真实世界派生的数据集的初步实证分析与我们的研究结果对齐。
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自成立以来,选择建模领域一直由理论驱动的建模方法主导。机器学习提供了一种用于建模行为的替代数据驱动方法,越来越越来越欣赏我们的领域。机器学习模型的交叉授粉,技术和实践有助于克服当前理论驱动的建模范式中遇到的问题和限制,例如模型选择的主观劳动密集型搜索过程,无法使用文本和图像数据。然而,尽管使用机器学习的进步来改善选择建模实践的潜在好处,但选择建模领域已经犹豫了拥抱机器学习。本讨论文件旨在巩固用于使用机器学习模型,技术和实践的知识,以获得选择建模,并讨论其潜力。因此,我们希望不仅希望在选择建模中进一步集成机器学习的情况是有益的,而且还可以进一步方便。为此,我们澄清了两个建模范式之间的相似性和差异;我们审查了机器学习选择建模;我们探讨了拥抱机器学习模式和技术的机会领域,以改善我们的实践。要结束本讨论文件,我们提出了一系列的研究问题,必须解决,以更好地了解机器学习如何受益选择建模。
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Recommender systems can strongly influence which information we see online, e.g., on social media, and thus impact our beliefs, decisions, and actions. At the same time, these systems can create substantial business value for different stakeholders. Given the growing potential impact of such AI-based systems on individuals, organizations, and society, questions of fairness have gained increased attention in recent years. However, research on fairness in recommender systems is still a developing area. In this survey, we first review the fundamental concepts and notions of fairness that were put forward in the area in the recent past. Afterward, through a review of more than 150 scholarly publications, we present an overview of how research in this field is currently operationalized, e.g., in terms of general research methodology, fairness measures, and algorithmic approaches. Overall, our analysis of recent works points to specific research gaps. In particular, we find that in many research works in computer science, very abstract problem operationalizations are prevalent, and questions of the underlying normative claims and what represents a fair recommendation in the context of a given application are often not discussed in depth. These observations call for more interdisciplinary research to address fairness in recommendation in a more comprehensive and impactful manner.
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We consider the problem of dynamic pricing of a product in the presence of feature-dependent price sensitivity. Developing practical algorithms that can estimate price elasticities robustly, especially when information about no purchases (losses) is not available, to drive such automated pricing systems is a challenge faced by many industries. Based on the Poisson semi-parametric approach, we construct a flexible yet interpretable demand model where the price related part is parametric while the remaining (nuisance) part of the model is non-parametric and can be modeled via sophisticated machine learning (ML) techniques. The estimation of price-sensitivity parameters of this model via direct one-stage regression techniques may lead to biased estimates due to regularization. To address this concern, we propose a two-stage estimation methodology which makes the estimation of the price-sensitivity parameters robust to biases in the estimators of the nuisance parameters of the model. In the first-stage we construct estimators of observed purchases and prices given the feature vector using sophisticated ML estimators such as deep neural networks. Utilizing the estimators from the first-stage, in the second-stage we leverage a Bayesian dynamic generalized linear model to estimate the price-sensitivity parameters. We test the performance of the proposed estimation schemes on simulated and real sales transaction data from the Airline industry. Our numerical studies demonstrate that our proposed two-stage approach reduces the estimation error in price-sensitivity parameters from 25\% to 4\% in realistic simulation settings. The two-stage estimation techniques proposed in this work allows practitioners to leverage modern ML techniques to robustly estimate price-sensitivities while still maintaining interpretability and allowing ease of validation of its various constituent parts.
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我们回顾了有关模型的文献,这些文献试图解释具有金钱回报的正常形式游戏所描述的社交互动中的人类行为。我们首先涵盖社会和道德偏好。然后,我们专注于日益增长的研究,表明人们对描述行动的语言做出反应,尤其是在激活道德问题时。最后,我们认为行为经济学正处于向基于语言的偏好转变的范式中,这将需要探索新的模型和实验设置。
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We apply classical statistical methods in conjunction with the state-of-the-art machine learning techniques to develop a hybrid interpretable model to analyse 454,897 online customers' behavior for a particular product category at the largest online retailer in China, that is JD. While most mere machine learning methods are plagued by the lack of interpretability in practice, our novel hybrid approach will address this practical issue by generating explainable output. This analysis involves identifying what features and characteristics have the most significant impact on customers' purchase behavior, thereby enabling us to predict future sales with a high level of accuracy, and identify the most impactful variables. Our results reveal that customers' product choice is insensitive to the promised delivery time, but this factor significantly impacts customers' order quantity. We also show that the effectiveness of various discounting methods depends on the specific product and the discount size. We identify product classes for which certain discounting approaches are more effective and provide recommendations on better use of different discounting tools. Customers' choice behavior across different product classes is mostly driven by price, and to a lesser extent, by customer demographics. The former finding asks for exercising care in deciding when and how much discount should be offered, whereas the latter identifies opportunities for personalized ads and targeted marketing. Further, to curb customers' batch ordering behavior and avoid the undesirable Bullwhip effect, JD should improve its logistics to ensure faster delivery of orders.
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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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在过去的五十年中,研究人员已经开发了设计和改进了应急响应管理(ERM)系统的统计,数据驱动,分析和算法方法。该问题已被认为是本质上的困难,并且构成了不确定性下的时空决策,这在文献中已经解决了不同的假设和方法。该调查提供了对这些方法的详细审查,重点关注有关四个子流程的关键挑战和问题:(a)事件预测,(b)入射检测,(c)资源分配,和(c)计算机辅助调度紧急响应。我们突出了该领域前后工作的优势和缺点,并探讨了不同建模范式之间的相似之处和差异。我们通过说明这种复杂领域未来研究的开放挑战和机会的结论。
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在过去二十年中,识别具有不同纵向数据趋势的群体的方法已经成为跨越许多研究领域的兴趣。为了支持研究人员,我们总结了文献关于纵向聚类的指导。此外,我们提供了一种纵向聚类方法,包括基于基团的轨迹建模(GBTM),生长混合模拟(GMM)和纵向K平均值(KML)。该方法在基本级别引入,并列出了强度,限制和模型扩展。在最近数据收集的发展之后,将注意这些方法的适用性赋予密集的纵向数据(ILD)。我们展示了使用R.中可用的包在合成数据集上的应用程序的应用。
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众筹是从许多人的贡献中筹集资金的行为,是经济理论中最受欢迎的研究主题之一。由于众筹平台(CFP)通过提供多个功能来促进筹集资金的过程,因此我们应该考虑它们在市场上的存在和生存。在这项研究中,我们研究了平台功能在客户行为选择模型中的重要作用。特别是,我们提出了一个多项式logit模型,以在众筹设置中描述客户的(支持者')行为。我们通过讨论这些平台中的收入分享模型来进行。为此,我们得出结论,分类优化问题可能至关重要,以最大程度地提高平台的收入。在某些情况下,我们能够得出合理数量的数据,并实施两种众所周知的机器学习方法,例如多元回归和分类问题,以预测平台可以为每个到达客户提供的最佳分类。我们比较了这两种方法的结果,并研究了它们在所有情况下的性能。
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