European Journal of Operational Research最新文献

Tactical workforce sizing and scheduling decisions for last-mile delivery

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-20 DOI: 10.1016/j.ejor.2024.12.006

Minakshi Punam Mandal, Alberto Santini, Claudia Archetti

{"title":"Tactical workforce sizing and scheduling decisions for last-mile delivery","authors":"Minakshi Punam Mandal, Alberto Santini, Claudia Archetti","doi":"10.1016/j.ejor.2024.12.006","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.006","url":null,"abstract":"We tackle the problems of workforce sizing and shift scheduling of a logistic operator delivering parcels in the last-mile segment of the supply chain. Our working hypothesis is that the relevant decisions are affected by two main trade-offs: workforce size and shift stability. A large workforce can deal with demand fluctuations but incurs higher fixed costs; by contrast, a small workforce might require excessive outsourcing to third-party logistic providers. Stable shifts, i.e., with predictable start times and lengths, improve worker satisfaction and reduce turnover; at the same time, they might be less able to adapt to an unsteady demand. We test these assumptions through an extensive computational campaign based on a novel mathematical formulation. We find that extreme shift stability is, indeed, unsuitable for last-mile operations. At the same time, introducing a very limited amount of flexibility achieves similar effects as moving to a completely flexible system while ensuring a better work-life balance for the workers. Several recent studies in the social sciences have warned about the consequences of precarious working conditions for couriers and retail workers and have recommended — among other things — stable work schedules. Our work shows that it is possible to offer better working conditions in terms of shift stability without sacrificing the company’s bottom line. Thus, companies prioritising profitability (as is often the case) can improve workers’ well-being and increase retention with a negligible cost impact.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"70 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The manufacturer’s resale strategy for trade-ins

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-17 DOI: 10.1016/j.ejor.2024.12.017

Shu Hu, Stuart X. Zhu, Ke Fu

{"title":"The manufacturer’s resale strategy for trade-ins","authors":"Shu Hu, Stuart X. Zhu, Ke Fu","doi":"10.1016/j.ejor.2024.12.017","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.017","url":null,"abstract":"To cope with the ever-increasing number of used cars, many automobile manufacturers now offer trade-in programs whereby they resell used cars to generate revenue. Consumers have the alternative of selling their used cars via an online peer-to-peer (P2P) resale platform, which charges a commission on each transaction. This paper studies a manufacturer’s traded-in resale strategy and assess how the manufacturer’s resale strategy and profits are affected by the presence of online P2P platforms. We find that in the absence of P2P platforms, the manufacturer may opt against implementing a resale program, whereas it will always do so in the presence of P2P platforms. This suggests a notable shift in manufacturers’ optimal choice of trade-in resale strategies due to the emergence of P2P platforms. Furthermore, the study reveals that the introduction of P2P platforms may diminishes the profits of manufacturers who have implemented a resale program. Importantly, the study underscores that manufacturers are not necessarily obliged to adopt a planned obsolescence strategy. When P2P platforms are absent, implementing a resale program allows manufacturers to increase profits by producing products that are either less or more durable. However, in the face of competition from P2P platforms, profitability can only be enhanced by making products more durable. This suggests that a platform’s emergence can alter how the depreciation rate affects a manufacturer’s profit and hence its optimal product design strategies. Understanding these dynamics is crucial for effectively navigating the growing used car market.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"125 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Formulating opinion dynamics from belief formation, diffusion and updating in social network group decision-making: Towards developing a holistic framework

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-16 DOI: 10.1016/j.ejor.2024.12.015

Tao Wen, Rui Zheng, Ting Wu, Zeyi Liu, Mi Zhou, Tahir Abbas Syed, Darminder Ghataoura, Yu-wang Chen

{"title":"Formulating opinion dynamics from belief formation, diffusion and updating in social network group decision-making: Towards developing a holistic framework","authors":"Tao Wen, Rui Zheng, Ting Wu, Zeyi Liu, Mi Zhou, Tahir Abbas Syed, Darminder Ghataoura, Yu-wang Chen","doi":"10.1016/j.ejor.2024.12.015","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.015","url":null,"abstract":"Interactions in social networks have become an integral part of people’s daily lives. In various decision-making situations, individuals usually hold diverse prior beliefs and engage in communication with their social connections to make informed decisions. However, most existing research focuses on isolated steps of this process, overlooking the overall complexity of decision-making in social networks. To bridge this important research gap, our paper aims to explore the key steps involved in the process and develop a holistic framework for analyzing how individuals form, exchange and update beliefs, ultimately leading to opinion dynamics and group decision behaviors in a social network. Specifically, relevant literature that focuses on different steps will be reviewed and drawn together to characterize the decision-making process in a comprehensive and systematic manner: individuals form initial beliefs following the principle of multiple criteria decision-making intuitively, information propagates in the social network and affects individuals’ beliefs differently in a form of social influence, beliefs evolve through dynamic interactions with others, and eventually individuals make their decisions, leading to group decision behaviors in the social network. Applications will be briefly discussed to illustrate the practical implications of this research. Finally, conclusions and future research outlook will be discussed in detail. It is expected that the holistic framework developed on the basis of the comprehensive literature review can provide in-depth insights into decision analysis in social networks and shed light on future research and applications towards effective integration of decision science, operational research, and social network analysis.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"24 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Robust optimal investment and consumption strategies with portfolio constraints and stochastic environment

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-12 DOI: 10.1016/j.ejor.2024.12.010

Len Patrick Dominic M. Garces, Yang Shen

{"title":"Robust optimal investment and consumption strategies with portfolio constraints and stochastic environment","authors":"Len Patrick Dominic M. Garces, Yang Shen","doi":"10.1016/j.ejor.2024.12.010","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.010","url":null,"abstract":"We investigate a continuous-time investment–consumption problem with model uncertainty in a general diffusion-based market with random model coefficients. We assume that a power utility investor is ambiguity-averse, with the preference to robustness captured by the homothetic multiplier robust specification, and the investor’s investment and consumption strategies are constrained to closed convex sets. To solve this constrained robust control problem, we employ the stochastic Hamilton–Jacobi–Bellman–Isaacs equations, backward stochastic differential equations, and bounded mean oscillation martingale theory. Furthermore, we show the investor incurs (non-negative) utility loss, i.e. the loss in welfare, if model uncertainty is ignored. When the model coefficients are deterministic, we establish formally the relationship between the investor’s robustness preference and the robust optimal investment–consumption strategy and the value function, and the impact of investment and consumption constraints on the investor’s robust optimal investment–consumption strategy and value function. Extensive numerical experiments highlight the significant impact of ambiguity aversion, consumption and investment constraints, on the investor’s robust optimal investment–consumption strategy, utility loss, and value function. Key findings include: (1) short-selling restriction always reduces the investor’s utility loss when model uncertainty is ignored; (2) the effect of consumption constraints on utility loss is more delicate and relies on the investor’s risk aversion level.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"18 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Connections between multiple-objective programming and weight restricted data envelopment analysis: The role of the ordering cone

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-12 DOI: 10.1016/j.ejor.2024.12.002

Pekka Korhonen, Majid Soleimani-damaneh, Jyrki Wallenius

引用次数: 0

Constraint learning approaches to improve the approximation of the capacity consumption function in lot-sizing models

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-10 DOI: 10.1016/j.ejor.2024.11.039

David Tremblet, Simon Thevenin, Alexandre Dolgui

{"title":"Constraint learning approaches to improve the approximation of the capacity consumption function in lot-sizing models","authors":"David Tremblet, Simon Thevenin, Alexandre Dolgui","doi":"10.1016/j.ejor.2024.11.039","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.11.039","url":null,"abstract":"Classical capacitated lot-sizing models include capacity constraints relying on a rough estimation of capacity consumption. The plans resulting from these models are often not executable on the shop floor. This paper investigates the use of constraint learning approaches to replace the capacity constraints in lot-sizing models with machine learning models. Integrating machine learning models into optimization models is not straightforward since the optimizer tends to exploit constraint approximation errors to minimize the costs. To overcome this issue, we introduce a training procedure that guarantees overestimation in the training sample. In addition, we propose an iterative training example generation approach. We perform numerical experiments with standard lot-sizing instances, where we assume the shop floor is a flexible job-shop. Our results show that the proposed approach provides 100% feasible plans and yields lower costs compared to classical lot-sizing models. Our methodology is competitive with integrated lot-sizing and scheduling models on small instances, and it scales well to realistic size instances when compared to the integrated approach.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"40 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A three-phase algorithm for the three-dimensional loading vehicle routing problem with split pickups and time windows

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-10 DOI: 10.1016/j.ejor.2024.12.005

Emeline Leloup, Célia Paquay, Thierry Pironet, José Fernando Oliveira

{"title":"A three-phase algorithm for the three-dimensional loading vehicle routing problem with split pickups and time windows","authors":"Emeline Leloup, Célia Paquay, Thierry Pironet, José Fernando Oliveira","doi":"10.1016/j.ejor.2024.12.005","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.005","url":null,"abstract":"In a survey of Belgian logistics service providers, the efficiency of first-mile pickup operations was identified as a key area for improvement, given the increasing number of returns in e-commerce, which has a significant impact on traffic congestion, carbon emissions, energy consumption and operational costs. However, the complexity of first-mile pickup operations, resulting from the small number of parcels to be collected at each pickup location, customer time windows, and the need to efficiently accommodate the highly heterogeneous cargo inside the vans, has hindered the development of real-world solution approaches. This article tackles this operational problem as a vehicle routing problem with time windows, time-dependent travel durations, and split pickups and integrates practical 3D container loading constraints such as vertical and horizontal stability as well as a more realistic reachability constraint to replace the classical “Last In First Out” (LIFO) constraint. To solve it, we propose a three-phase heuristic based on a savings constructive heuristic, an extreme point concept for the loading aspect and a General Variable Neighborhood Search as an improvement phase for both routing and packing. Numerical experiments are conducted to assess the performance of the algorithm on benchmark instances and new instances are tested to validate the positive managerial impacts on cost when allowing split pickups and on driver working duration when extending customer time windows. In addition, we show the impacts of considering the reachability constraint on cost and of the variation of speed during peak hours on schedule feasibility.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"16 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Does the quantity discount mechanism offer a loophole for retailer collusion? Impacts and responses

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-09 DOI: 10.1016/j.ejor.2024.12.007

Shaofu Du, Xiahui Sun, Li Hu, Tsan-Ming Choi

{"title":"Does the quantity discount mechanism offer a loophole for retailer collusion? Impacts and responses","authors":"Shaofu Du, Xiahui Sun, Li Hu, Tsan-Ming Choi","doi":"10.1016/j.ejor.2024.12.007","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.007","url":null,"abstract":"The quantity discount mechanism is an effective and widely used tool by manufacturers to encourage downstream retailers to increase their order volumes. As wholesale prices decrease with larger order quantities, retailers have an incentive to collude and achieve joint procurement. Two joint procurement modes—group buying (GB) and agency procurement (AP)—are considered to characterize the phenomenon of retailer collusion. In GB mode, retailers purchase as a group and enjoy the same per-unit wholesale price. In contrast, in the AP mode, a leading retailer assumes responsibility for aggregating orders and submitting the total order to the manufacturer while having the authority to set the resale price. A dual-channel model is developed to investigate joint procurement among competing retailers, aiming to identify its underlying driving forces and impacts. Our findings indicate that, compared to individual purchasing (IP), GB is always attainable for retailers, whereas AP is only attainable under intense competition when retailers are symmetric. We reveal that retailers engaging in joint procurement do not always aim to achieve lower wholesale prices. In some cases, the objective may be to mitigate price competition. This finding suggests that joint procurement by retailers results in a reduction in total order quantity, which significantly diminishes the manufacturer’s profit. In response to the challenges of retailer collusion, we explore the feasibility and potential value of offering a coordinated quantity discount mechanism, wherein the manufacturer gives up the pursuit of maximizing its own profit in favor of optimizing the profits of the entire supply chain, making concessions to the retailers. We identify the scenarios in which a coordinated quantity discount contract can eliminate the loophole for retailer collusion and highlight both the value and necessity of achieving contract coordination.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"41 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Milk adulteration testing and impact of farmers efficiency heterogeneity: A strategic analysis

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-09 DOI: 10.1016/j.ejor.2024.12.001

Samir Biswas, Preetam Basu, Balram Avittathur

{"title":"Milk adulteration testing and impact of farmers efficiency heterogeneity: A strategic analysis","authors":"Samir Biswas, Preetam Basu, Balram Avittathur","doi":"10.1016/j.ejor.2024.12.001","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.12.001","url":null,"abstract":"Driven by economic motives, dairy farmers adulterate milk to increase its perceived quality, posing a serious risk to consumer health. We analyse a milk supply chain in which smallholder dairy farmers can adulterate milk and explore the feasibility of selling it to end consumers through an aggregator. Using a non-cooperative sequential game between the aggregator and farmers, we examine the impact of two testing strategies offered by the aggregator to curb adulteration - (i) individual (testing milk procured from each farmer individually) and (ii) composite (testing the milk after aggregating the portions procured from all the farmers). Our analyses reveal that the aggregator can control milk adulteration by judiciously using testing and penalty mechanisms. We find that a higher market price <ce:italic>(aggregation effect)</ce:italic>, fetched by the aggregator because of its bargaining power owing to the consolidation of milk supplies, is essential for its operation. It leads to higher revenue for the aggregator and expands the zone in which it is profitable for the aggregator to operate. However, our results show that the <ce:italic>efficiency heterogeneity</ce:italic> among farmers, which leads to the less efficient farmers free-riding on the more efficient ones, has a detrimental effect on the aggregator operation. We also explore the impact of <ce:italic>external uncertainties</ce:italic> on the supply chain and observe that the composite testing strategy becomes more profitable for the aggregator when external uncertainties increase. Our results provide important policy recommendations for aggregators adopting optimal testing strategies.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"28 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Learning from the aggregated optimum: Managing port wine inventory in the face of climate risks

IF 6.4 2区管理学

European Journal of Operational Research Pub Date : 2024-12-07 DOI: 10.1016/j.ejor.2024.11.046

Alexander Pahr, Martin Grunow, Pedro Amorim

{"title":"Learning from the aggregated optimum: Managing port wine inventory in the face of climate risks","authors":"Alexander Pahr, Martin Grunow, Pedro Amorim","doi":"10.1016/j.ejor.2024.11.046","DOIUrl":"https://doi.org/10.1016/j.ejor.2024.11.046","url":null,"abstract":"Port wine stocks ameliorate during storage, facilitating product differentiation according to age. This induces a trade-off between immediate revenues and further maturation. Varying climate conditions in the limited supply region lead to stochastic purchase prices for wine grapes. Decision makers must integrate recurring purchasing, production, and issuance decisions. Because stocks from different age classes can be blended to create final products, the solution space increases exponentially in the number of age classes. We model the problem of managing port wine inventory as a Markov decision process, considering decay as an additional source of uncertainty. For small problems, we derive general management strategies from the long-run behavior of the optimal policy. Our solution approach for otherwise intractable large problems, therefore, first aggregates age classes to create a tractable problem representation. We then use machine learning to train tree-based decision rules that reproduce the optimal aggregated policy and the enclosed management strategies. The derived rules are scaled back to solve the original problem. Learning from the aggregated optimum outperforms benchmark rules by 21.4% in annual profits (while leaving a 2.8%-gap to an upper bound). For an industry case, we obtain a 17.4%-improvement over current practices. Our research provides distinct strategies for how producers can mitigate climate risks. The purchasing policy dynamically adapts to climate-dependent price fluctuations. Uncertainties are met with lower production of younger products, whereas strategic surpluses of older stocks ensure high production of older products. Moreover, a wide spread in the age classes used for blending reduces decay risk exposure.","PeriodicalId":55161,"journal":{"name":"European Journal of Operational Research","volume":"250 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0