Pub Date : 2025-04-04DOI: 10.1016/j.orl.2025.107285
Hang Chen , Genjiu Xu , Li Zhang
Group-buying leverages collective purchasing power, with invitations boosting volume and profit. This paper proposes Proportional-with-Leader-Bonus (PLB) rules, allocating profit by purchasing volume and rewarding leaders for invitations. To prevent fake invitations and collusion, False-Name-Proof (FNP) and Consolidation-Proof (CP) are analyzed. Leader Income Consistency (LIC) and Bilateral Ratio Consistency (BRC) ensure fair leader rewards and balance purchasing volume and invitations. The PLB rules are axiomatically characterized by Single-person efficiency, FNP, CP, LIC, and BRC, providing a robust framework for fair profit allocation.
{"title":"Proportional-with-Leader-Bonus rules for group-buying with invitation behavior","authors":"Hang Chen , Genjiu Xu , Li Zhang","doi":"10.1016/j.orl.2025.107285","DOIUrl":"10.1016/j.orl.2025.107285","url":null,"abstract":"<div><div>Group-buying leverages collective purchasing power, with invitations boosting volume and profit. This paper proposes Proportional-with-Leader-Bonus (PLB) rules, allocating profit by purchasing volume and rewarding leaders for invitations. To prevent fake invitations and collusion, False-Name-Proof (FNP) and Consolidation-Proof (CP) are analyzed. Leader Income Consistency (LIC) and Bilateral Ratio Consistency (BRC) ensure fair leader rewards and balance purchasing volume and invitations. The PLB rules are axiomatically characterized by Single-person efficiency, FNP, CP, LIC, and BRC, providing a robust framework for fair profit allocation.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107285"},"PeriodicalIF":0.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-04DOI: 10.1016/j.orl.2025.107295
Cheng Lu
We present a refined analysis of a variant of the algorithm in the literature for solving the knapsack-constrained submodular maximization problem. By deriving a strong approximation bound for this variant, we reduce the size of the sets requiring enumeration, from two to one, to ensure the final algorithm achieves 1/4-approximation. As a result, we obtain the fastest deterministic algorithm so far which achieves an approximation ratio of 1/4 for the problem.
{"title":"A note on fast deterministic algorithms for non-monotone submodular maximization under a knapsack constraint","authors":"Cheng Lu","doi":"10.1016/j.orl.2025.107295","DOIUrl":"10.1016/j.orl.2025.107295","url":null,"abstract":"<div><div>We present a refined analysis of a variant of the algorithm in the literature for solving the knapsack-constrained submodular maximization problem. By deriving a strong approximation bound for this variant, we reduce the size of the sets requiring enumeration, from two to one, to ensure the final algorithm achieves 1/4-approximation. As a result, we obtain the fastest deterministic algorithm so far which achieves an approximation ratio of 1/4 for the problem.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107295"},"PeriodicalIF":0.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-02DOI: 10.1016/j.orl.2025.107287
Ankur Sinha , Satender Gunwal
We introduce a linear programming-based approach for hyperparameter tuning of machine learning models. The approach finetunes continuous hyperparameters and model parameters through a linear program, enhancing model generalization in the vicinity of an initial model. The proposed method converts hyperparameter optimization into a bilevel program and identifies a descent direction to improve validation loss. The results demonstrate improvements in most cases across regression, machine learning, and deep learning tasks, with test performance enhancements ranging from 0.3% to 28.1%.
{"title":"A linear programming-based hyper local search for tuning hyperparameters","authors":"Ankur Sinha , Satender Gunwal","doi":"10.1016/j.orl.2025.107287","DOIUrl":"10.1016/j.orl.2025.107287","url":null,"abstract":"<div><div>We introduce a linear programming-based approach for hyperparameter tuning of machine learning models. The approach finetunes continuous hyperparameters and model parameters through a linear program, enhancing model generalization in the vicinity of an initial model. The proposed method converts hyperparameter optimization into a bilevel program and identifies a descent direction to improve validation loss. The results demonstrate improvements in most cases across regression, machine learning, and deep learning tasks, with test performance enhancements ranging from 0.3% to 28.1%.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107287"},"PeriodicalIF":0.8,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01DOI: 10.1016/j.orl.2025.107286
Ioannis Avramopoulos, Prodromos Makris, Emmanouel Varvarigos
Normal backwardation manifests when the futures price of a commodity is below the expected future spot price. In this paper, we show how businesses can optimally leverage backwardation in their supply chain optimization. To that end, we derive the optimal amount a business ought to purchase in the futures market to take advantage of the favorable futures price in order to minimize the overall expected procurement cost. We further use Hoeffding's inequality to predict the manifestation of demand aggregators.
{"title":"Optimal procurement under backwardation and the benefits of the manifestation of demand aggregators","authors":"Ioannis Avramopoulos, Prodromos Makris, Emmanouel Varvarigos","doi":"10.1016/j.orl.2025.107286","DOIUrl":"10.1016/j.orl.2025.107286","url":null,"abstract":"<div><div>Normal backwardation manifests when the futures price of a commodity is below the expected future spot price. In this paper, we show how businesses can optimally leverage backwardation in their supply chain optimization. To that end, we derive the optimal amount a business ought to purchase in the futures market to take advantage of the favorable futures price in order to minimize the overall expected procurement cost. We further use Hoeffding's inequality to predict the manifestation of demand aggregators.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107286"},"PeriodicalIF":0.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-31DOI: 10.1016/j.orl.2025.107281
Sheldon M. Ross, Tianchi Zhao
We study the problem of finding a normal population whose mean is at least as large as some specified value m. Assuming a sampling cost, the objective is to minimize the expected total discounted cost until there is a population whose mean is at least m with probability at least α. We propose several heuristic policies as well as a linear programming approach.
{"title":"Finding a good normal population","authors":"Sheldon M. Ross, Tianchi Zhao","doi":"10.1016/j.orl.2025.107281","DOIUrl":"10.1016/j.orl.2025.107281","url":null,"abstract":"<div><div>We study the problem of finding a normal population whose mean is at least as large as some specified value <em>m</em>. Assuming a sampling cost, the objective is to minimize the expected total discounted cost until there is a population whose mean is at least <em>m</em> with probability at least <em>α</em>. We propose several heuristic policies as well as a linear programming approach.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107281"},"PeriodicalIF":0.8,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143737992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Given the complete graph on n vertices, where , we define two Hamiltonian cycles as cyclic disjoint if, for each pair of vertices, the distance between them in one Hamiltonian cycle differs from the distance between them in the other Hamiltonian cycle. We investigate the number of pairwise cyclic disjoint tours that exist in . Specifically, we identify when pairs of cyclic disjoint tours can occur and provide a procedure to generate pairwise cyclic disjoint tours, where m is the smallest prime factor of n. Finally, we demonstrate that the number of pairwise cyclic disjoint tours is maximized when n is prime.
{"title":"On queens and tours","authors":"Pieter Jacobs, Andrés López Martínez, Frits Spieksma","doi":"10.1016/j.orl.2025.107283","DOIUrl":"10.1016/j.orl.2025.107283","url":null,"abstract":"<div><div>Given the complete graph on <em>n</em> vertices, where <span><math><mi>n</mi><mo>≥</mo><mn>3</mn></math></span>, we define two Hamiltonian cycles as <em>cyclic disjoint</em> if, for each pair of vertices, the distance between them in one Hamiltonian cycle differs from the distance between them in the other Hamiltonian cycle. We investigate the number of pairwise cyclic disjoint tours that exist in <span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span>. Specifically, we identify when pairs of cyclic disjoint tours can occur and provide a procedure to generate <span><math><mfrac><mrow><mi>m</mi><mo>−</mo><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> pairwise cyclic disjoint tours, where <em>m</em> is the smallest prime factor of <em>n</em>. Finally, we demonstrate that the number <span><math><mfrac><mrow><mi>m</mi><mo>−</mo><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> of pairwise cyclic disjoint tours is maximized when <em>n</em> is prime.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107283"},"PeriodicalIF":0.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143737991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1016/j.orl.2025.107282
Clinton Gubong Gassi , Eric Kamwa
This paper introduces the q-fixed majority property for committee selection rules, which extends the traditional fixed majority principle to a flexible framework. We examine conditions under which the committee scoring rules satisfy the q-fixed majority property. Focusing on (weakly) separable rules, we find that the Bloc rule is the only which satisfies it for all . In addition, the q-bottom majority property is introduced, highlighting conditions under which committees can be excluded based on voter consensus.
{"title":"q-fixed majority efficiency of committee scoring rules","authors":"Clinton Gubong Gassi , Eric Kamwa","doi":"10.1016/j.orl.2025.107282","DOIUrl":"10.1016/j.orl.2025.107282","url":null,"abstract":"<div><div>This paper introduces the <em>q</em>-fixed majority property for committee selection rules, which extends the traditional fixed majority principle to a flexible framework. We examine conditions under which the committee scoring rules satisfy the <em>q</em>-fixed majority property. Focusing on (weakly) separable rules, we find that the Bloc rule is the only which satisfies it for all <span><math><mi>q</mi><mo>></mo><mn>1</mn><mo>/</mo><mn>2</mn></math></span>. In addition, the <em>q</em>-bottom majority property is introduced, highlighting conditions under which committees can be excluded based on voter consensus.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"61 ","pages":"Article 107282"},"PeriodicalIF":0.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143737990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-20DOI: 10.1016/j.orl.2025.107279
Yaşar Levent Koçağa
Motivated by service systems where staffing decisions must be made before the arrival rate becomes known, we study the constraint satisfaction problem in an Erlang-A queue facing a random arrival rate. The objective is to find the minimum staffing level subject to a service level constraint that is modeled either (1) via an average constraint formulation that ensures a given quality-of-service (QoS) target holds on average by bounding the average fraction of abandoning customers below the said QoS target or (2) via a chance constraint formulation that ensures the QoS target for the random fraction of abandoning customers is met with high probability. Our primary contribution, under each constraint formulation, is to propose a policy that is shown to be universally optimal, i.e., irrespective of the magnitude of randomness in the arrival rate, the staffing gap between the proposed policy and the exact optimal policy remains bounded as the system size grows large. To the best of our knowledge, this is the first universal performance guarantee for constraint satisfaction in Erlang-A queues with random arrival rates and complements a recent result on cost minimization. The practical importance of this universality is that our proposed policy is a “one-size-fits-all” that is guaranteed to perform well for all levels of arrival rate uncertainty.
{"title":"Universally optimal staffing for Erlang-A queues facing uncertain arrival rates: The case of constraint satisfaction","authors":"Yaşar Levent Koçağa","doi":"10.1016/j.orl.2025.107279","DOIUrl":"10.1016/j.orl.2025.107279","url":null,"abstract":"<div><div>Motivated by service systems where staffing decisions must be made before the arrival rate becomes known, we study the <em>constraint satisfaction</em> problem in an Erlang-A queue facing a <em>random</em> arrival rate. The objective is to find the minimum staffing level subject to a service level constraint that is modeled either (1) via an <em>average constraint</em> formulation that ensures a given quality-of-service (QoS) target holds on average by bounding the <em>average</em> fraction of abandoning customers below the said QoS target or (2) via a <em>chance constraint</em> formulation that ensures the QoS target for the random fraction of abandoning customers is met with high <em>probability</em>. Our primary contribution, under each constraint formulation, is to propose a policy that is shown to be universally optimal, i.e., <em>irrespective</em> of the magnitude of randomness in the arrival rate, the staffing gap between the proposed policy and the exact optimal policy remains bounded as the system size grows large. To the best of our knowledge, this is the first universal performance guarantee for constraint satisfaction in Erlang-A queues with random arrival rates and complements a recent result on cost minimization. The practical importance of this universality is that our proposed policy is a “one-size-fits-all” that is guaranteed to perform well for <em>all</em> levels of arrival rate uncertainty.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"60 ","pages":"Article 107279"},"PeriodicalIF":0.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-20DOI: 10.1016/j.orl.2025.107275
Ashwini Soundararajan, F.P. Barbhuiya
This paper presents a time-dependent solution for the system-content distribution of the infinite buffer queue. The supplementary variable and the difference equation technique is used to obtain the probabilities in terms of Laplace transform. Some relevant performance measures are derived and extensive numerical results are presented. It covers a comparison of the impact of heavy-tailed and light-tailed interarrival time distributions on the transient behavior of the system and the underlying system characteristics.
{"title":"Transient analysis of a renewal input multiserver queueing model with infinite buffer","authors":"Ashwini Soundararajan, F.P. Barbhuiya","doi":"10.1016/j.orl.2025.107275","DOIUrl":"10.1016/j.orl.2025.107275","url":null,"abstract":"<div><div>This paper presents a time-dependent solution for the system-content distribution of the infinite buffer <span><math><mi>G</mi><mi>I</mi><mo>/</mo><mi>M</mi><mo>/</mo><mi>c</mi></math></span> queue. The supplementary variable and the difference equation technique is used to obtain the probabilities in terms of Laplace transform. Some relevant performance measures are derived and extensive numerical results are presented. It covers a comparison of the impact of heavy-tailed and light-tailed interarrival time distributions on the transient behavior of the system and the underlying system characteristics.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"60 ","pages":"Article 107275"},"PeriodicalIF":0.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.orl.2025.107280
Jaehyuk Choi
This study proposes a fast exact simulation scheme for the Ornstein–Uhlenbeck driven stochastic volatility model. With the Karhunen–Loève expansions, the stochastic volatility path (Ornstein–Uhlenbeck process) is expressed as a sine series, and the time integrals of volatility and variance are analytically derived as infinite series of independent normal random variables. The new method is several hundred times faster than the existing method using numerical transform inversion. The simulation variance is further reduced with conditional simulation and the control variate.
{"title":"Exact simulation scheme for the Ornstein–Uhlenbeck driven stochastic volatility model with the Karhunen–Loève expansions","authors":"Jaehyuk Choi","doi":"10.1016/j.orl.2025.107280","DOIUrl":"10.1016/j.orl.2025.107280","url":null,"abstract":"<div><div>This study proposes a fast exact simulation scheme for the Ornstein–Uhlenbeck driven stochastic volatility model. With the Karhunen–Loève expansions, the stochastic volatility path (Ornstein–Uhlenbeck process) is expressed as a sine series, and the time integrals of volatility and variance are analytically derived as infinite series of independent normal random variables. The new method is several hundred times faster than the existing method using numerical transform inversion. The simulation variance is further reduced with conditional simulation and the control variate.</div></div>","PeriodicalId":54682,"journal":{"name":"Operations Research Letters","volume":"60 ","pages":"Article 107280"},"PeriodicalIF":0.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"管理学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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