Abstract Overselling is commonly adopted in the travel and hospitality sectors where a good or service is sold in excess of actual supply. We examine the impact of consumer foresight on efficient overselling when there are two dimensions of uncertainty, namely, early consumers are uncertain about their service valuations and the seller is uncertain about late demand arrival. We show that when consumers are naïve and have no foresight to anticipate future events, the seller resorts to the use of partial refunds and involuntary cancellation when the mandatory compensation for seller‐initiated cancellation is low, resulting in efficiency loss. When consumers are sophisticated and have perfect foresight on future events, efficiency is achieved when the seller sells the entire capacity in advance and relies solely on voluntary cancellation to re‐sell units when late demand warrants it. Refund complements overselling both by improving allocation efficiency in involuntary cancellation and by mitigating the cost of overselling when consumers have limited foresight. Unlike the social planner, the seller may suffer from consumer foresight. Our findings pinpoint the mandatory compensation in involuntary cancellation as a strategic tool for the social planner to tilt the seller's preference in the seller‐initiated cancellation policy to achieve efficient overselling.
{"title":"Impact of consumer foresight on efficient overselling","authors":"Man Yu, Wei Shi Lim","doi":"10.1002/nav.22158","DOIUrl":"https://doi.org/10.1002/nav.22158","url":null,"abstract":"Abstract Overselling is commonly adopted in the travel and hospitality sectors where a good or service is sold in excess of actual supply. We examine the impact of consumer foresight on efficient overselling when there are two dimensions of uncertainty, namely, early consumers are uncertain about their service valuations and the seller is uncertain about late demand arrival. We show that when consumers are naïve and have no foresight to anticipate future events, the seller resorts to the use of partial refunds and involuntary cancellation when the mandatory compensation for seller‐initiated cancellation is low, resulting in efficiency loss. When consumers are sophisticated and have perfect foresight on future events, efficiency is achieved when the seller sells the entire capacity in advance and relies solely on voluntary cancellation to re‐sell units when late demand warrants it. Refund complements overselling both by improving allocation efficiency in involuntary cancellation and by mitigating the cost of overselling when consumers have limited foresight. Unlike the social planner, the seller may suffer from consumer foresight. Our findings pinpoint the mandatory compensation in involuntary cancellation as a strategic tool for the social planner to tilt the seller's preference in the seller‐initiated cancellation policy to achieve efficient overselling.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135092919","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}
Abstract The model of adaptive progressive Type‐II censoring introduced by Ng et al. (2009) (referred to as Ng–Kundu–Chan model) is extended to allow switching from a given initial censoring plan to any arbitrary given plan of the same length. In this generalized model, the joint distribution of the failure times and the corresponding likelihood function is derived. It is illustrated that the computation of maximum likelihood and Bayesian estimates are along the same lines as for standard progressive Type‐II censoring. However, the distributional properties of the estimators will usually be different since the censoring plan actually applied in the (generalized) Ng–Kundu–Chan model is random. As already mentioned in Cramer and Iliopoulos (2010), we directly show that the normalized spacings are independent and identically exponentially distributed. However, it turns out that the spacings themselves are generally dependent with mixtures of exponential distributions as marginals. These results are used to study linear estimators. Finally, we propose an algorithm for generating random numbers in the generalized Ng–Kundu–Chan model and present some simulation results. The results obtained also provide new findings in the original Ng–Kundu–Chan model; the corresponding implications are highlighted.
{"title":"Generalized Ng–Kundu–Chan model of adaptive progressive Type‐II censoring and related inference","authors":"Anja Bettina Schmiedt, Erhard Cramer","doi":"10.1002/nav.22152","DOIUrl":"https://doi.org/10.1002/nav.22152","url":null,"abstract":"Abstract The model of adaptive progressive Type‐II censoring introduced by Ng et al. (2009) (referred to as Ng–Kundu–Chan model) is extended to allow switching from a given initial censoring plan to any arbitrary given plan of the same length. In this generalized model, the joint distribution of the failure times and the corresponding likelihood function is derived. It is illustrated that the computation of maximum likelihood and Bayesian estimates are along the same lines as for standard progressive Type‐II censoring. However, the distributional properties of the estimators will usually be different since the censoring plan actually applied in the (generalized) Ng–Kundu–Chan model is random. As already mentioned in Cramer and Iliopoulos (2010), we directly show that the normalized spacings are independent and identically exponentially distributed. However, it turns out that the spacings themselves are generally dependent with mixtures of exponential distributions as marginals. These results are used to study linear estimators. Finally, we propose an algorithm for generating random numbers in the generalized Ng–Kundu–Chan model and present some simulation results. The results obtained also provide new findings in the original Ng–Kundu–Chan model; the corresponding implications are highlighted.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135347698","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}
Abhishek Srivastava, Tsan‐Ming Choi, Aarushi Mahajan, Vivek Roy
Abstract Gray markets are infamous for unauthorized diversion of authentic products at lower prices to harm the manufacturer's authorized distribution channel. Hence, manufacturers are becoming more proactive in shaping strategies that can counter gray markets. By considering the risk of unauthorized selling through gray markets, we analyze the manufacturer's strategic channel choice and product upgrade decision. We analytically explore the provision of granting flexibility to the legitimate retailer to adjust price during the selling season as a strategy to cope with gray market. We find that unauthorized selling through gray markets has a severe negative impact on the manufacturer's profitability depending on the degree of channel differentiation and product brand equity. We counter‐intuitively reveal that the overall decentralized supply chain can be better‐off, owing to higher product leakage, especially because the legitimate retailer gains an increased sales volume through product diversion to the gray market. However, the manufacturer's loss is more severe in such a decentralized supply chain. We show that the manufacturer can eliminate unauthorized sales through gray market by offering price adjustment flexibility to the retailer. Another compelling finding exhibits that the manufacturer's decision to launch an upgraded product can intensify the diversion of an existing product. However, unfair competition from the unauthorized channel cannibalizes the sales of an upgraded product, thereby making the manufacturer worse‐off. Interestingly, despite the cannibalization of upgraded product sales, the manufacturer can be better‐off in terms of overall profitability via price adjustment flexibility if both the degree of upgrade and brand equity are higher. Overall, in addition to deploying monitoring mechanisms for supervising legitimate retailers, price adjustment flexibility can reduce product diversion if the degree of upgrade is moderate and channel differentiation is higher.
{"title":"Impacts of gray market selling on the supply chain under product upgrade and pricing flexibility decisions","authors":"Abhishek Srivastava, Tsan‐Ming Choi, Aarushi Mahajan, Vivek Roy","doi":"10.1002/nav.22157","DOIUrl":"https://doi.org/10.1002/nav.22157","url":null,"abstract":"Abstract Gray markets are infamous for unauthorized diversion of authentic products at lower prices to harm the manufacturer's authorized distribution channel. Hence, manufacturers are becoming more proactive in shaping strategies that can counter gray markets. By considering the risk of unauthorized selling through gray markets, we analyze the manufacturer's strategic channel choice and product upgrade decision. We analytically explore the provision of granting flexibility to the legitimate retailer to adjust price during the selling season as a strategy to cope with gray market. We find that unauthorized selling through gray markets has a severe negative impact on the manufacturer's profitability depending on the degree of channel differentiation and product brand equity. We counter‐intuitively reveal that the overall decentralized supply chain can be better‐off, owing to higher product leakage, especially because the legitimate retailer gains an increased sales volume through product diversion to the gray market. However, the manufacturer's loss is more severe in such a decentralized supply chain. We show that the manufacturer can eliminate unauthorized sales through gray market by offering price adjustment flexibility to the retailer. Another compelling finding exhibits that the manufacturer's decision to launch an upgraded product can intensify the diversion of an existing product. However, unfair competition from the unauthorized channel cannibalizes the sales of an upgraded product, thereby making the manufacturer worse‐off. Interestingly, despite the cannibalization of upgraded product sales, the manufacturer can be better‐off in terms of overall profitability via price adjustment flexibility if both the degree of upgrade and brand equity are higher. Overall, in addition to deploying monitoring mechanisms for supervising legitimate retailers, price adjustment flexibility can reduce product diversion if the degree of upgrade is moderate and channel differentiation is higher.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135645042","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}
Abstract On retailing platforms, several information‐provision technologies are adopted to gain profit, such as production video ads service, live streaming service, and virtual reality/augmented reality tech. In this article, we focus on the investment strategies of information‐provision tech and its impact on the platform‐based supply chain. To this end, we develop a general model under which the platform invests in information‐provision tech for homogenous sellers and consumers search for products on the platform. Our results show that the platform should adopt a higher investment level in information‐provision tech for the products with the unit search cost or products' information uncertainty degree being medium. Also, a more competitive environment can lead to a lower platform's investment level in information‐provision tech when the number of browsing products is sufficiently large. Interestingly, we find that for a large unit search cost or small uncertainty degree of products' information, investing in information‐provision tech can benefit the platform's and sellers' profit. In addition, if the number of browsing products is large, investing in information‐provision tech can increase the consumer surplus and social welfare. Lastly, our results hold for a broad class of distributions of products' information uncertainty value and other practical cases. Our studies can help the platform to understand the roles of information‐provision tech and provide some practical management insights.
{"title":"Investment strategies of information‐provision technology in the platform‐based supply chain","authors":"Xu Tian, Mingzheng Wang, Yang Xu","doi":"10.1002/nav.22155","DOIUrl":"https://doi.org/10.1002/nav.22155","url":null,"abstract":"Abstract On retailing platforms, several information‐provision technologies are adopted to gain profit, such as production video ads service, live streaming service, and virtual reality/augmented reality tech. In this article, we focus on the investment strategies of information‐provision tech and its impact on the platform‐based supply chain. To this end, we develop a general model under which the platform invests in information‐provision tech for homogenous sellers and consumers search for products on the platform. Our results show that the platform should adopt a higher investment level in information‐provision tech for the products with the unit search cost or products' information uncertainty degree being medium. Also, a more competitive environment can lead to a lower platform's investment level in information‐provision tech when the number of browsing products is sufficiently large. Interestingly, we find that for a large unit search cost or small uncertainty degree of products' information, investing in information‐provision tech can benefit the platform's and sellers' profit. In addition, if the number of browsing products is large, investing in information‐provision tech can increase the consumer surplus and social welfare. Lastly, our results hold for a broad class of distributions of products' information uncertainty value and other practical cases. Our studies can help the platform to understand the roles of information‐provision tech and provide some practical management insights.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135898795","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}
Abstract It has been challenging for firms to effectively manage demand when they release products of one generation after another one. Motivated by the observations from the smartphone industry, this paper investigates the effectiveness of two demand management strategies in the presence of a product rollover: the upgrade program and price markdown policy. Under an upgrade program, a firm allows customers to upgrade their on‐hand product to a new generation product that will be released in a future time. Under a markdown pricing policy, the firm offers a discount for the currently available product so as to induce waiting customers to make immediate purchases. The two demand management strategies target different groups of customers and have distinct impacts on customers' choices. Starting from the time‐varying choice behavior of a heterogeneous group of customers, we study the optimal pricing decisions involved in the two strategies. Specifically, when customers are myopic in the sense that they only make a one‐time purchasing decision upon arrival, we show that the firm should offer the upgrade program only when the innovation level of the new product is relatively high, and the firm's optimal upgrade price can increase over time. Generally, the firm should offer the upgrade program during the early selling period and adopt markdown pricing as the release date of the new product approaches. Numerical experiments reveal that the dynamic upgrade program and markdown pricing policies can help improve profit significantly. When customers are strategic in the sense that they can monitor the selling prices and make dynamic purchasing decisions until they buy a unit of product, we examine two coping strategies that a firm can adopt, and investigate how the strategic monitoring behavior may influence a firm's optimal selling decisions and profit.
{"title":"Managing demand by upgrade programs and markdown pricing with a product rollover","authors":"Yongbo Xiao, Chen Hu, Qian Liu","doi":"10.1002/nav.22156","DOIUrl":"https://doi.org/10.1002/nav.22156","url":null,"abstract":"Abstract It has been challenging for firms to effectively manage demand when they release products of one generation after another one. Motivated by the observations from the smartphone industry, this paper investigates the effectiveness of two demand management strategies in the presence of a product rollover: the upgrade program and price markdown policy. Under an upgrade program, a firm allows customers to upgrade their on‐hand product to a new generation product that will be released in a future time. Under a markdown pricing policy, the firm offers a discount for the currently available product so as to induce waiting customers to make immediate purchases. The two demand management strategies target different groups of customers and have distinct impacts on customers' choices. Starting from the time‐varying choice behavior of a heterogeneous group of customers, we study the optimal pricing decisions involved in the two strategies. Specifically, when customers are myopic in the sense that they only make a one‐time purchasing decision upon arrival, we show that the firm should offer the upgrade program only when the innovation level of the new product is relatively high, and the firm's optimal upgrade price can increase over time. Generally, the firm should offer the upgrade program during the early selling period and adopt markdown pricing as the release date of the new product approaches. Numerical experiments reveal that the dynamic upgrade program and markdown pricing policies can help improve profit significantly. When customers are strategic in the sense that they can monitor the selling prices and make dynamic purchasing decisions until they buy a unit of product, we examine two coping strategies that a firm can adopt, and investigate how the strategic monitoring behavior may influence a firm's optimal selling decisions and profit.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135424951","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}
Abstract Accelerated degradation tests (ADTs) are widely used to assess lifetime information under normal use conditions for highly reliable products. For the accelerated tests, two basic assumptions are that changing stress levels does not affect the underlying distribution family and that there is stochastic ordering for the life distributions at different stress levels. The acceleration invariance (AI) principle for ADTs is proposed to study these fundamental assumptions. Using the AI principle, a theoretical connection between the model parameters and the accelerating variables is developed for Hougaard processes. This concept can be extended to heterogeneous gamma and inverse Gaussian processes. Simulation studies are presented to support the applicability and flexibility of the Hougaard process using the AI principle for ADTs. A real data analysis using the derived relationship is used to validate the AI principle for accelerated degradation analysis. All technical details, simulation results for nonlinear cases and model mis‐specification analysis are available online as Supporting Information.
{"title":"Acceleration invariance principle for Hougaard processes in degradation analysis","authors":"Chien‐Yu Peng, Yi‐Shian Dong, Tsai‐Hung Fan","doi":"10.1002/nav.22153","DOIUrl":"https://doi.org/10.1002/nav.22153","url":null,"abstract":"Abstract Accelerated degradation tests (ADTs) are widely used to assess lifetime information under normal use conditions for highly reliable products. For the accelerated tests, two basic assumptions are that changing stress levels does not affect the underlying distribution family and that there is stochastic ordering for the life distributions at different stress levels. The acceleration invariance (AI) principle for ADTs is proposed to study these fundamental assumptions. Using the AI principle, a theoretical connection between the model parameters and the accelerating variables is developed for Hougaard processes. This concept can be extended to heterogeneous gamma and inverse Gaussian processes. Simulation studies are presented to support the applicability and flexibility of the Hougaard process using the AI principle for ADTs. A real data analysis using the derived relationship is used to validate the AI principle for accelerated degradation analysis. All technical details, simulation results for nonlinear cases and model mis‐specification analysis are available online as Supporting Information.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135345071","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}
Abstract While the previous literature on green technology adoption has not fully considered information sharing, we consider the impact of demand information sharing on the adoption of green technologies by risk‐averse farmers in a vertical agricultural supply chain. We find that government subsidies and information sharing do not always promote farmers' adoption of green technologies. The accuracy of the information plays a vital role in promoting farmers' adoption of green technologies; however, the increased green technology adoption induced by more accurate information may be detrimental to farmer welfare in the presence of production diseconomies. Information sharing can reduce the amount of government subsidies for promoting green technology adoption, thereby suggesting the substitutable role of information and monetary instruments. Nonetheless, information‐sharing may lead to lower water savings and thus should be adopted with caution. Risk aversion has a nontrivial impact on agricultural technology adoption: farmers are more likely to adopt traditional agricultural technologies when their risk aversion is either very low or very high. Finally, we validate our decision model with U.S. Department of Agriculture cotton production data and propose management insights to help farmers make appropriate adoption decisions under information asymmetry and risk‐averse attitudes.
{"title":"Farmers' green technology adoption: Implications from government subsidies and information sharing","authors":"Xianpei Hong, Ying‐Ju Chen, Yeming Gong, Hua Wang","doi":"10.1002/nav.22150","DOIUrl":"https://doi.org/10.1002/nav.22150","url":null,"abstract":"Abstract While the previous literature on green technology adoption has not fully considered information sharing, we consider the impact of demand information sharing on the adoption of green technologies by risk‐averse farmers in a vertical agricultural supply chain. We find that government subsidies and information sharing do not always promote farmers' adoption of green technologies. The accuracy of the information plays a vital role in promoting farmers' adoption of green technologies; however, the increased green technology adoption induced by more accurate information may be detrimental to farmer welfare in the presence of production diseconomies. Information sharing can reduce the amount of government subsidies for promoting green technology adoption, thereby suggesting the substitutable role of information and monetary instruments. Nonetheless, information‐sharing may lead to lower water savings and thus should be adopted with caution. Risk aversion has a nontrivial impact on agricultural technology adoption: farmers are more likely to adopt traditional agricultural technologies when their risk aversion is either very low or very high. Finally, we validate our decision model with U.S. Department of Agriculture cotton production data and propose management insights to help farmers make appropriate adoption decisions under information asymmetry and risk‐averse attitudes.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134886410","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}
Abstract Increasing environmental concerns and e‐commerce has attracted a growing focus on reverse logistics that not only delivers some goods to customers but also picks up other goods from customers. To achieve cost‐efficient and fast deliveries, integrating drones into the delivery and pickup services provides a competitive advantage, which however increases the operational challenges. We consider a truck‐drone routing problem with simultaneous delivery and pickup, where each truck carries a set of heterogeneous drones. Each truck can simultaneously perform its own delivery and pickup, and serve as an intermediate movable depot from which multiple drones can be dispatched to serve customers when the truck arrives at a customer, and the truck must wait until all the drones return. The energy consumption of drones is considered during their flights. All the delivery services must be performed, whereas the pickup services are optional with certain rewards. The objective is to find the synthetic‐routes of the truck‐drone combinations so as to minimize the sum of the assignment cost and the transport cost of the trucks and drones minus the total pickup revenue. To solve the problem, we devise a tailored branch‐and‐price‐and‐cut algorithm incorporating a specialized two‐stage bidirectional labeling algorithm to solve the challenging pricing problem. To enhance the efficiency of the algorithm, we use the subset‐row inequalities to tighten the lower bound, and apply some heuristic pricing strategies to quickly solve the pricing problem. We perform extensive numerical studies to assess the performance of the developed algorithm, analyze the merit of the truck‐drone cooperative service mode over the truck‐only service mode and the superiority of the configuration with heterogeneous drones, and ascertain the impacts of the key model parameters to generate managerial insights. We also show how our model would perform should it be used for the medical supply delivery and pickup in Shenzhen, China.
{"title":"A branch‐and‐price‐and‐cut algorithm for the truck‐drone routing problem with simultaneously delivery and pickup","authors":"Dongwei Li, Joshua Ignatius, Dujuan Wang, Yunqiang Yin, T.C.E. Cheng","doi":"10.1002/nav.22151","DOIUrl":"https://doi.org/10.1002/nav.22151","url":null,"abstract":"Abstract Increasing environmental concerns and e‐commerce has attracted a growing focus on reverse logistics that not only delivers some goods to customers but also picks up other goods from customers. To achieve cost‐efficient and fast deliveries, integrating drones into the delivery and pickup services provides a competitive advantage, which however increases the operational challenges. We consider a truck‐drone routing problem with simultaneous delivery and pickup, where each truck carries a set of heterogeneous drones. Each truck can simultaneously perform its own delivery and pickup, and serve as an intermediate movable depot from which multiple drones can be dispatched to serve customers when the truck arrives at a customer, and the truck must wait until all the drones return. The energy consumption of drones is considered during their flights. All the delivery services must be performed, whereas the pickup services are optional with certain rewards. The objective is to find the synthetic‐routes of the truck‐drone combinations so as to minimize the sum of the assignment cost and the transport cost of the trucks and drones minus the total pickup revenue. To solve the problem, we devise a tailored branch‐and‐price‐and‐cut algorithm incorporating a specialized two‐stage bidirectional labeling algorithm to solve the challenging pricing problem. To enhance the efficiency of the algorithm, we use the subset‐row inequalities to tighten the lower bound, and apply some heuristic pricing strategies to quickly solve the pricing problem. We perform extensive numerical studies to assess the performance of the developed algorithm, analyze the merit of the truck‐drone cooperative service mode over the truck‐only service mode and the superiority of the configuration with heterogeneous drones, and ascertain the impacts of the key model parameters to generate managerial insights. We also show how our model would perform should it be used for the medical supply delivery and pickup in Shenzhen, China.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136313416","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}
Abstract Log‐concavity of multivariate distributions is an important concept in general and has a very special place in the field of Reliability Theory. An attempt has been made in this paper to study preservation results for (i) the discrete version of multivariate log‐concavity for multistate series and multistate parallel systems consisting of independent components, states of both components and systems being represented by elements in a subset of and (ii) the continuous version of multivariate log‐concavity under multistate series and multistate parallel systems made up of independent components and states of both, systems and components, taking values in the set . These results for discrete and continuous versions of log‐concavity have also been extended to systems that are formed using both multistate series and multistate‐parallel systems. Further, the results in (ii) have been used to obtain important and useful bounds on joint probabilities related to times spent by multistate components, multistate series, multistate parallel systems, and the combinations thereof.
{"title":"Bounds for joint probabilities of multistate systems using preservation of log‐concavity","authors":"Sanjeev Sabnis, Priyanka Majumder, Shyamal Ghosh","doi":"10.1002/nav.22149","DOIUrl":"https://doi.org/10.1002/nav.22149","url":null,"abstract":"Abstract Log‐concavity of multivariate distributions is an important concept in general and has a very special place in the field of Reliability Theory. An attempt has been made in this paper to study preservation results for (i) the discrete version of multivariate log‐concavity for multistate series and multistate parallel systems consisting of independent components, states of both components and systems being represented by elements in a subset of and (ii) the continuous version of multivariate log‐concavity under multistate series and multistate parallel systems made up of independent components and states of both, systems and components, taking values in the set . These results for discrete and continuous versions of log‐concavity have also been extended to systems that are formed using both multistate series and multistate‐parallel systems. Further, the results in (ii) have been used to obtain important and useful bounds on joint probabilities related to times spent by multistate components, multistate series, multistate parallel systems, and the combinations thereof.","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307144","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 : 2023-02-01Epub Date: 2022-10-26DOI: 10.1002/nav.22083
Paola Martin, Diwakar Gupta, Timothy Pruett
This paper provides a methodology for predicting post-transplant kidney function, that is, the 1-year post-transplant estimated Glomerular Filtration Rate (eGFR-1) for each donor-candidate pair. We apply customized machine-learning algorithms to pre-transplant donor and recipient data to determine the probability of achieving an eGFR-1 of at least 30 ml/min. This threshold was chosen because there is insufficient survival benefit if the kidney fails to generate an eGFR-1 ≥ 30 ml/min. For some donor-candidate pairs, the developed algorithm provides highly accurate predictions. For others, limitations of previous transplants' data results in noisier predictions. However, because the same kidney is offered to many candidates, we identify those pairs for whom the predictions are highly accurate. Out of 6977 discarded older-donor kidneys that were a match with at least one transplanted kidney, 5282 had one or more identified candidate, who were offered that kidney, did not accept any other offer, and would have had ≥80% chance of achieving eGFR-1 ≥ 30 ml/min, had the kidney been transplanted. We also show that transplants with ≥80% chance of achieving eGFR-1 ≥ 30 ml/min and that survive 1 year have higher 10-year death-censored graft survival probabilities than all older-donor transplants that survive 1 year (73.61% vs. 70.48%, respectively).
{"title":"Predicting older-donor kidneys' post-transplant renal function using pre-transplant data.","authors":"Paola Martin, Diwakar Gupta, Timothy Pruett","doi":"10.1002/nav.22083","DOIUrl":"10.1002/nav.22083","url":null,"abstract":"<p><p>This paper provides a methodology for predicting post-transplant kidney function, that is, the 1-year post-transplant estimated Glomerular Filtration Rate (eGFR-1) for each donor-candidate pair. We apply customized machine-learning algorithms to pre-transplant donor and recipient data to determine the probability of achieving an eGFR-1 of at least 30 ml/min. This threshold was chosen because there is insufficient survival benefit if the kidney fails to generate an eGFR-1 ≥ 30 ml/min. For some donor-candidate pairs, the developed algorithm provides highly accurate predictions. For others, limitations of previous transplants' data results in noisier predictions. However, because the same kidney is offered to many candidates, we identify those pairs for whom the predictions are highly accurate. Out of 6977 discarded older-donor kidneys that were a match with at least one transplanted kidney, 5282 had one or more identified candidate, who were offered that kidney, did not accept any other offer, and would have had ≥80% chance of achieving eGFR-1 ≥ 30 ml/min, had the kidney been transplanted. We also show that transplants with ≥80% chance of achieving eGFR-1 ≥ 30 ml/min and that survive 1 year have higher 10-year death-censored graft survival probabilities than all older-donor transplants that survive 1 year (73.61% vs. 70.48%, respectively).</p>","PeriodicalId":49772,"journal":{"name":"Naval Research Logistics","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/54/34/NAV-70-21.PMC10108525.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9754530","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}
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