Direct Shipment Research Articles

한국 타이어산업에서 다양한 수송타입을 이용한 그린공급망의 최적화

This study proposes a methodology for the design and efficient operation strategy of the Green Supply Chain (GSC) network considering various transport types. Since the GSC network integrates forward and reverse logistics, it can increase profit through sales of reusable products and increase the efficiency of inventory management by securing recyclable raw materials, thereby further strengthening the competitiveness of enterprises. In this study, the GSC network is designed based on the case of the Korean tire industry, various types of transportation have been used by adding direct delivery (DDL) and direct shipment (DSP) to the normal delivery(NDL). Maximization of total revenue and minimization of total cost were considered as the objective function of the mathematical model, and various constraints were considered to optimize the objective function. In order to find the optimal result of the objective function, the genetic algorithm (GA) verification method was used to solve the problem.

Adaptive meta-heuristic algorithms for flexible supply chain network design problem with different delivery modes

Flexible supply chain networks are one of the most effective class of supply chains in both manufacturing and service sectors. In such networks, different delivery modes can significantly influence the efficiency of the entire supply chain. In this paper, a mixed integer linear programming (MILP) model is proposed for a multi-product four-stage flexible supply chain network design (SCND) problem in a solid transportation environment. The presented model considers three different delivery modes namely normal delivery, direct shipment and direct delivery. Since the problem is NP-hard, meta-heuristic approaches should be used to solve it. For this aim, ten classical and adaptive meta-heuristic algorithms are developed. In order to calibrate the parameters of the proposed algorithms, a typical experimental study is done. After the parameter setting stage, the final experiments on some randomly generated test problems are performed. The Obtained results demonstrate that the proposed adaptive vibration damping optimization (AVDO) algorithm performs better than the other algorithms.

Solution techniques for the inter-modal pickup and delivery problem in two regions

This work addresses the routing problem faced by transportation carriers and postal services that transport small parcels in large quantities. By splitting the territory into regions, these service providers can adapt a three-part network structure and solve a pickup and delivery problem with long-hauls without direct shipments between regions. That is, bilateral cross-city and cross-country requests must be met while also fulfilling capacity and time window constraints. To address this challenge, this work limits the problem to two regions and thereby can identify the correlations and synchronization between different modes. The proposed solution approach decomposes the problem into two subproblems: a long-haul assignment that can be solved exactly, and a short-haul routing problem that must be solved heuristically. The result is an efficient matheuristic, whose quality is confirmed through a comparison with findings from previous literature; it is viable in terms of solution quality and computation time. Long-haul flexibility also influences short-haul routing cost, such that improvements of up to 22% are possible merely by increasing long-haul flexibility but not long-haul cost. Finally, realistic instances are solved based on the inter-library loan system comparing the influence of selecting train or truck on the SH routing costs.

Municipal solid waste management with cost minimization and emission control objectives: A case study of Ankara

Proper management of municipal solid waste (MSW) has been a crucial aspect of every society due to its social, environmental, and economic impacts. Operations research techniques have frequently focused on cost minimization objectives in locational planning of municipal solid waste management (MSWM) systems. However, transportation constitutes an integral part of this system producing a considerable amount of greenhouse gas (GHG) emissions. Therefore, sustainable management of this system with GHG emissions minimization considerations is necessary to preserve the resources and protect the environment. In this study, a bi-objective optimization model is proposed to minimize system cost and carbon dioxide (CO2) emission resulting from transportation activities in locational planning of MSWM systems. The proposed model is applied to MSWM system of Ankara to introduce transfer stations (TSs). Two extensions of the current system are examined, namely, the extended and hybrid systems, where MSW is only transported through TSs in the former, while direct shipments are also allowed in the latter. For both extensions, it is observed that with no or little increase in cost, considerable savings in emission can be achieved. Simulation analyses show that CO2 emission and cost are not subject to a considerable change due to speed variations of vehicles.

A comparison of formulations for a three-level lot sizing and replenishment problem with a distribution structure

We address a three-level lot sizing and replenishment problem with a distribution structure (3LSPD), which is an extension of the one-warehouse multi-retailer problem (OWMR). We consider one production plant that produces one type of item over a discrete and finite planning horizon. The items produced are used to replenish warehouses and then retailers using direct shipments. Each retailer is linked to a unique warehouse and there are no transfers between warehouses nor between retailers. We also assume that transportation is uncapacitated. However, we consider the possibility of imposing production capacity constraints at the production plant level. The objective is to minimize the sum of the fixed production and replenishment costs and of the variable inventory holding costs at all three levels. We compare 13 different MIP formulations to solve the problem. All of these formulations are adapted from existing MIP formulations found in the one-warehouse multi-retailer literature, but most formulations are new in the context of the 3LSPD. We run experiments on both balanced and unbalanced networks. Our results indicate that the multi-commodity formulation is well suited for uncapacititated instances and that the echelon stock reformulations are better for capacitated instances. They also show that the richer formulations are not necessarily the best ones and that the unbalanced instances are harder to solve.

Mathematical formulation and heuristic algorithms for optimisation of auto-part milk-run logistics network considering forward and reverse flow of pallets

The operational planning of distribution network for automotive industry is complex with many conditions to consider, including heterogeneous fleet, enforcing the feasibility of 3D-packing of pallets into vehicles to address the vehicle's capacity in terms of weight and volume, compatibility of orders in a vehicle, returning empty pallets from assembly-plants backwards to suppliers, and delivery time windows. A mathematical model (MILP) is proposed that takes account of these conditions to minimise total transportation costs. The network structure can be a combination of direct shipment and milk-run for both forward and reverse flow of pallets. The model is solved optimally for small-size problems. For solving larger problems, a heuristic algorithm (in two versions) is proposed that uses a similarity measure to generate a reasonable list of orders. Best/first-fit strategies are employed to generate a feasible solution with the aid of a relaxed version of the proposed MILP. Improvement heuristics are also designed. Unlike most of existing constructive heuristics, our aim for developing the heuristic approach is to force routing decision, with all of its considerations, being made optimal. We also use the proposed best-fit strategy in the body of grouping evolution strategy (GES) algorithm to attain an effective meta-heuristic approach. The effectiveness of heuristics is tested on generated instances which demonstrates they are optimal for small-size problems. They are also tested on the data of daily auto-parts shipments gathered from the largest Iranian automobile company. Results demonstrate there exists a significant potential for cost saving through milk-run strategy compared with the direct shipping strategy.

Location, inventory and testing decisions in closed-loop supply chains: A multimedia company

Our partnering firm is a Chinese manufacturer of multimedia products that needs guidance developing its imminent Closed-Loop Supply Chain (CLSC). To study this problem, we take into account location, inventory, and testing decisions in a CLSC setting with stochastic demands of new and time-sensitive returned products. Our analysis pays particular attention to the different roles assigned to the reverse Distribution Centers (DCs) and how each option affects the optimal CLSC design. The roles considered are collection and consolidation, additional testing tasks, and direct shipments with no reverse DCs. The problem concerning our partnering firm is formulated as a scenario-based chance-constrained mixed-integer program and it is reformulated to a conic quadratic mixed-integer program that can be solved efficiently via commercial optimization packages. The completeness of the model proposed allows us to develop a decision support tool for the firm and to offer several useful managerial insights. These insights are inferred from our computational experiments using data from the Chinese firm and a second data set based on the U.S. geography. Particularly interesting insights are related to how changes in the reverse flows can impact the forward supply chain and the inventory dynamics concerning the joint DCs.

An integrated production and distribution problem with direct shipment: a case from Moroccan bottled-water market

We consider an industrial application encountered in the Moroccan context that involves the production and distribution of bottled water. Our industrial partner owns one plant from which all requests are delivered in direct shipments and usually full truckloads to the customers (a set of regional depots and wholesalers). We must take into account the production, the delivery requirements, multiple products, and inventory levels. The objective is to minimise the sum of the production, transportation, and inventory costs. We propose a mixed integer linear program for a variant of the multi-vehicle, multi-product production routing problem. Experiments have been conducted using CPLEX 12.3.0, and almost all instances were solved with a reasonable optimality gap. The results show that significant savings can be obtained by using our approach with respect to the current company practice.

Determining an optimal warehouse location, capacity, and product allocation in a multi-product, multi-period distribution network: a case study

This paper addresses the distribution network design problem in a complex four-echelon supply chain system that includes factories, internal warehouses, external warehouses and customers. The distribution network contains a large number of products and considers 20 periods of planning horizon. Product deliveries are made using two shipment methods, direct shipment from internal warehouse and through shared external warehouse, to two groups of customers, domestic and overseas, with deterministic demands. The objective is to determine an optimal location of a new external warehouse, its capacity, and product-facility-market allocation so as to minimise the total logistics cost, including transportation and warehousing costs. A real-world large-scale problem from industry is solved optimally using a mixed integer linear programming model. A sensitivity analysis on three key parameters, product demand, unit transportation cost, and unit warehousing cost, is conducted to find the final solution.

An integrated production and distribution problem with direct shipment: a case from Moroccan bottled-water market

An integrated production and distribution problem with direct shipment: a case from Moroccan bottled-water market

A Multi-Product Production/Distribution System Design Problem with Direct Shipments and Lateral Transshipments

In this paper, we investigate a multi-product, three-stage production/distribution system design problem (PDSD) with direct shipment and lateral transshipment capabilities. Our overall goal is to find the most efficient network design to minimize the total fixed facility and transportation costs. Specifically, we locate p capacitated distribution centers in the second stage from a set of candidate locations. At the same time, our design allows for direct shipments between first (suppliers) and third stages (customers) and lateral transshipments among the distribution centers in the second stage. The PDSD problem is known to be NP-hard, and prior studies have explored several heuristic methods including scatter search, tabu search, and genetic algorithms to solve the problem. In this paper, we propose two solution algorithms based on simulated annealing and GRASP heuristics. We apply both long-term and short-term memory lists to maintain an efficient local search, combined with a custom greedy solver that can effectively evaluate the quality of a solution candidate. We conduct a series of computational experiments to validate the proposed algorithms. Compared with the optimal solution, the simulated annealing algorithm presents an average optimality gap of 0.07% and an average time of 25.56% of optimal solution time, while the GRASP algorithm achieves a solution gap of 0.11% with 17.85% of optimal running time. The experimental results also show that the simulated annealing and GRASP algorithms outperform the best-reported heuristic in the literature based on scatter search regarding both solution quality and duration, especially for large-scale problem instances with tighter capacities.

Trade-offs between the stepwise cost function and its linear approximation for the modular hub location problem

There exist situations where the transportation cost is better estimated as a function of the number of vehicles required for transporting a load, rather than a linear function of the load. This provides a stepwise cost function, which defines the so-called Modular Hub Location Problem (MHLP, or HLP with modular capacities) that has received increasing attention in the last decade. In this paper, we consider formulations to be solved by exact methods. We show that by choosing a specific generalized linear cost function with slope and intercept depending on problem data, one minimizes the measurement deviation between the two cost functions and obtains solutions close to those found with the stepwise cost function, while avoiding the higher computational complexity of the latter. As a side contribution, we look at the savings induced by using direct shipments in a hub and spoke network, given the better ability of a stepwise cost function to incorporate direct transportation. Numerical experiments are conducted over benchmark HLP instances of the OR-library.

Recycling of End-of-Life Vehicles in Small Islands: The Case of Kinmen, Taiwan

The abandoned end-of-life vehicle (ELV) problem in small islands has negative effects on local sustainable development, and the treatment of ELVs in island scale is usually difficult. This study presents the investigation of the material flows and economic analysis on the ELVs in small islands by the case study of Kinmen, Taiwan. The ELVs generation amount is estimated using the population balance model (PBM) and the results showed a steep increase in the future for both automobiles and motorcycles. The insufficient ELV treatment capacity has resulted in the significant informal treatment flow, which will be the total weight of 1906 tons of items with market value, with a potential economic gain of 16.9 million TWD in 2050. The results of the economic characterization of the local dismantling business clarified that profitability is the main hindrance for the development of new dismantling business due to high transportation costs. Our results suggested that implementation of the different subsidy rate according to the treatment area under the current policy or creation of a new treatment flow with a direct shipment of ELVs for treatment is necessary to improve the utilization of the stocked materials from untreated ELVs.

A Three-level Location-inventory Problem With Perishable Product

This article studies a three-level multi-product location-inventory problem in which location, allocation and inventory decisions are taken in a three-level supply chain including plants, distribution centers and retailers. The direct shipment from plant to retailer is allowed and two-echelon inventory and demand correlation among retailers are considered in this supply chain network. A mixed integer nonlinear programming formulation is presented to describe the problem and trade off the costs of setup, transportation, inventory and deterioration. Then it is transformed to a conic quadratic mixed integer programming formulation and solved with a standard optimization software packages-CPLEX. In addition, we demonstrate that the distribution network allowing for direct shipment from plant to retailer is more optimal than the distribution network ignoring it in the three-level supply chain network with perishable product.

Lessons learnt from a porcine epidemic diarrhea (PED) case in France in 2014: Descriptive epidemiology and control measures implemented

An acute epidemic of porcine epidemic diarrhea (PED) has affected the USA since 2013 and spread all around the world. In France, the immune status of the pig population against PED virus (PEDV) was expected to be low due to the absence of circulation of the virus since the 80′s and a compulsory notification of PED was set up in 2014. Here, we reported the first case of a PED outbreak in December 2014 in the North of France after a long absence of the disease, the monitoring of the excretion and the control measure implementation. The isolated strain in France in December 2014 was a PEDV “S-InDel” strain which was close to the “S-InDel” German PEDV strain isolated in May 2014. The individual shedding duration of PEDV in feces was estimated around 20 days for pigs of different ages. Biosecurity measures implemented allowed the limitation of PEDV spread to fattening and farrowing rooms without dissemination to the nursery block. Using strict biosecurity measures, direct shipment of infected fatteners to the slaughterhouse, strict decontamination protocols with a quarantine of 6 weeks for replacement gilts without voluntary contamination helped PEDV fade out within the herd and avoided the spread to other herds. PEDV presence in manure was investigated as well as the inactivation treatment of the virus present in the liquid manure. An increase to a pH 12 of liquid manure by liming led to the absence of PEDV detection by RT-PCR after seven days.

Vehicle routing problem in a kanban controlled supply chain system considering cross-docking strategy

This paper considers an inventory-routing problem in a distribution network in which kanban is used as a means to implement just-in-time strategy. There are a set of part suppliers and cross-docks in this network, which provide parts for an assembly plant. A novel mixed integer non-linear programming formulation is developed for the problem in which the optimum number of kanbans is determined considering inventory and transportation cost. In the other word, this research aims at reducing the level of inventory and transportation cost in a kanban controlled supply chain system, in which the number of kanbans is to be determined optimally considering demand from suppliers and geographical distribution of them. A fleet of vehicles is applied to transport kanbans from suppliers to the assembly plant via two transportation strategies: direct shipment and shipment through cross-docks (indirect shipment). In the second strategy, it is possible to have routes between suppliers. The proposed problem is NP-hard based on literature, thus a memetic algorithm is introduced to solve it. Solving several examples reveals that the solving method significantly outperforms GAMS/CPLEX in reducing objective value and computational time.

Waste shipments for energy recovery as a waste treatment strategy for small islands: the case of Kinmen, Taiwan

Waste management is more challenging in small islands due to islands’ special characteristics. For small islands where energy recovery by incineration is difficult due to smaller waste generation amount with large seasonal fluctuations, waste shipments outside of island can make energy recovery possible. This study evaluated the cost effectiveness and environmental performance of waste shipments for energy recovery in case of small islands. The results shown that the direct shipment for incineration is expensive, but the emission prevention by energy recovery can surpass the emission from waste transportation. Waste shipments in the form of refused derived fuel (RDF) can reduce the transportation and incineration cost, but the high fossil fuel consumption in RDF production process resulted in high greenhouse gas emissions. The shipping distance, RDF gate fee, and emission from RDF production process have high influence on the cost effectiveness and environmental performance of the waste treatment process. The results of this study revealed the cost effective and environmental beneficial choosing criteria of waste shipments’ destination.

Simultaneous Pricing, Routing, and Inventory Control for Perishable Goods in a Two-echelon Supply Chain

Due to the rapid development of technology in recent years, market competition and customer expectations have increased more than ever. In this situation, it is vital for businesses survival to determine the appropriate policy for inventory control, pricing, and routing, and decisions regarding each of them are often made separately. If the products have a perishable nature, it will be more important to determ ine the above policies. For integration of the decision-making concerning the three key components of the supply chain ,i.e. pricing, routing, and inventory control, two mathematical models were developed for a two-echelon supply chain of perishable items with direct shipment, where fixed lifetime is assumed in one model and random lifetime in another, so that profit is maximized. The proposed mathematical model was solved using the CPLEX solver package of the GAMS software for specification of the optimal policy of the supply chain. The results demonstrated that the CPU time needed for solving the mathematical model for perishable items with random lifetime was less than that for fixed lifetime, while the value of the objective function for products with fixed lifetime was greater than that for products with random lifetime.

Hybrid Genetic Algorithm for Optimizing the Closed-Loop Supply Chain Model with Direct Shipment and Delivery

Hybrid Genetic Algorithm for Optimizing the Closed-Loop Supply Chain Model with Direct Shipment and Delivery

Analysis of an improved branch-and-cut formulation for the Inventory-Routing Problem with Transshipment

The Inventory-Routing Problem with Transshipment (IRPT) is an extension of the Inventory-Routing Problem (IRP), in which not only the supplier can deliver goods to the retailers, but also transshipments between retailers or between the supplier and a retailer are possible. In this paper, we investigate the branch-and-cut (B&C) formulation of the IRPT and propose four different types of improvements for it. We first develop two new sets of valid inequalities for the problem which greatly strengthen the linear relaxation of the problem. We then improve the bounds on the continuous delivery variables and use these improved bounds to tighten the inventory management constraints. Next, we reformulate the routing component of the problem by exploiting the possible presence of direct shipments in the optimal solution. Finally, we prove that some integer and continuous variables can be eliminated out of the mathematical formulation. Experimental results demonstrate that these improvements drastically reduce the computational burden for solving the IRPT to optimality. On a large set of benchmark instances our proposed branch-and-cut algorithm, which integrates these improvements, outperforms the current best results in the literature. In addition, we are able to find the optimal solutions for two instances whose optimal solution was not known until now.