An appropriate understanding and accurate estimation of zonal freight production(FP)and attraction(FA)volume is one of the most important topics and the initial step in developing the origin and destination(OD)matrix....An appropriate understanding and accurate estimation of zonal freight production(FP)and attraction(FA)volume is one of the most important topics and the initial step in developing the origin and destination(OD)matrix.In general,zonal FP and FA are difficult to be obtained as observed data,particularly in developing countries,owing to the lack of large-scale freight surveys.Thus,several proxy indicators are often used for estimating FP and FA,such as the gross regional product(GRP),population,and the number of establishments.However,these indicators do not often estimate the zonal FP and FA accurately and are even not available readily.The nighttime light intensity(NLI)data that is human-induced light emission data and one of the open alternative data,possibly improves the accuracy of FP and FA estimation.However,few studies have examined the relationship between NLI and FP/FA.Therefore,the objectives of this study are to examine whether NLI can be a significant indicator for estimating zonal FP and FA relative to other socio-economic indicators and to examine the types of NLIs that can accurately estimate the FP and FA through a case study in Japan.As a result of the analysis,NLI data are identified as a significant variable for the estimation of FP and FA among various socio-economic variables.Although some of the indicators related to secondary industries provide higher accuracy,NLI exhibits better estimates than the popular indicators such as GRP and population.In addition,we propose three types of total NLI that multiply the unit NLI by the zonal area and this generates higher accuracy of unit NLI,the average light intensity of all pixels in a zone.We have also found that the use of habitable area for the estimation of total NLI provides the highest accuracy among the four types of NLIs including unit NLI.Through the analysis,NLI data is sufficiently applicable for estimating zonal FP and FA,relative to other important socio-economic indicators,although space transferability should be examined in other study areas.These findings could help estimating FP/FA particularly in countries and regions with limited statistical data available.展开更多
The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Su...The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.展开更多
One of the most important responsibilities of a supply chain manager is to decide “how much” (or “many”) of inventory items to order and how to transport them. This paper presents four mixed-integer linear program...One of the most important responsibilities of a supply chain manager is to decide “how much” (or “many”) of inventory items to order and how to transport them. This paper presents four mixed-integer linear programming models to help supply chain managers make these decisions for multiple products subject to multiple constraints when suppliers offer quantity discounts and shippers offer freight discounts. Each model deals with one of the possible combinations of all-units, incremental quantity discounts, all-weight and incremental freight discounts. The models are based on a piecewise linear approximation of the number of orders function. They allow any number of linear constraints and determine if independent or common (fixed) cycle ordering has a lower total cost. Results of computational experiments on an example problem are also presented.展开更多
基金supported by The Kurata Grants:The Hitachi Global Foundation,grant number 1445.
文摘An appropriate understanding and accurate estimation of zonal freight production(FP)and attraction(FA)volume is one of the most important topics and the initial step in developing the origin and destination(OD)matrix.In general,zonal FP and FA are difficult to be obtained as observed data,particularly in developing countries,owing to the lack of large-scale freight surveys.Thus,several proxy indicators are often used for estimating FP and FA,such as the gross regional product(GRP),population,and the number of establishments.However,these indicators do not often estimate the zonal FP and FA accurately and are even not available readily.The nighttime light intensity(NLI)data that is human-induced light emission data and one of the open alternative data,possibly improves the accuracy of FP and FA estimation.However,few studies have examined the relationship between NLI and FP/FA.Therefore,the objectives of this study are to examine whether NLI can be a significant indicator for estimating zonal FP and FA relative to other socio-economic indicators and to examine the types of NLIs that can accurately estimate the FP and FA through a case study in Japan.As a result of the analysis,NLI data are identified as a significant variable for the estimation of FP and FA among various socio-economic variables.Although some of the indicators related to secondary industries provide higher accuracy,NLI exhibits better estimates than the popular indicators such as GRP and population.In addition,we propose three types of total NLI that multiply the unit NLI by the zonal area and this generates higher accuracy of unit NLI,the average light intensity of all pixels in a zone.We have also found that the use of habitable area for the estimation of total NLI provides the highest accuracy among the four types of NLIs including unit NLI.Through the analysis,NLI data is sufficiently applicable for estimating zonal FP and FA,relative to other important socio-economic indicators,although space transferability should be examined in other study areas.These findings could help estimating FP/FA particularly in countries and regions with limited statistical data available.
文摘The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.
文摘One of the most important responsibilities of a supply chain manager is to decide “how much” (or “many”) of inventory items to order and how to transport them. This paper presents four mixed-integer linear programming models to help supply chain managers make these decisions for multiple products subject to multiple constraints when suppliers offer quantity discounts and shippers offer freight discounts. Each model deals with one of the possible combinations of all-units, incremental quantity discounts, all-weight and incremental freight discounts. The models are based on a piecewise linear approximation of the number of orders function. They allow any number of linear constraints and determine if independent or common (fixed) cycle ordering has a lower total cost. Results of computational experiments on an example problem are also presented.
