Collaboration in transportation between two or more agents is becoming an important approach to find efficient solutions or plans. Efficiency can be measured in, for example, lower cost or more ...flexibility. An important aspect of the collaboration is to decide on how to share the benefits—for example, cost, profit, or resources. There are many sharing mechanisms or cost allocations proposed in the literature. Some are based on simple proportional rules and others are based on theoretical concepts found in game theory. We provide a survey on cost allocation methods found in the literature on collaborative transportation, including problems on planning, vehicle routing, traveling salesman, distribution, and inventory. A total of 55 scientific articles compose the main part of the survey, most of them published between 2010 and 2015. We identify more than 40 cost allocation methods used in this stream of literature. We describe the theoretical basis for the main methods as well as the cases where they are used. We also report savings from the collaborations when they are based on industrial data. Some directions for future research are discussed.
In a competitive environment, effective management of production and inventory decisions is critical to maintain an efficient and balanced flow of the supply chain system. Manufacturing companies ...across supply chains have recognised that inventories can be managed more effectively through increased collaboration and better coordination. In practice, production planning and inventory control decisions are not separated, and supply chain members can significantly reduce costs through the coordination of production and inventory decisions. Research in this field has received much attention in recent years. This study aims to review coordination, cooperation, and collaboration (CCC) mechanisms in production-inventory studies. By using an established research methodology, a total of 118 articles were reviewed and the implemented CCC mechanisms were classified into three main categories: contractual practices, joint decision-making practices, and information-sharing practices. By examining the selected articles according to the implemented methodologies and their impact on the sustainably of supply chains, research gaps and future directions for academics and practitioners were identified. This study shows that more research is needed to discover the impact of combining different CCC mechanisms on supply chain efficiency in terms of economic, environmental, and social concerns.
•Overlapping coalitions for first time studied in collabortive transportation.•Integer linear models help finding the best coalition configuration.•Coalition configuration adds flexibility and ...improves results of coalition structures.•Large case on forest biomass: 27 companies, 200,000 transports, 6 million tons, 17 terawatt hours.•Potential benefits: 8% cost savings.
Most literature on collaborative transportation has focused on cost allocation, assuming as given which companies take part in the collaboration. However, a primary problem is the formation of coalitions. In this article, we study the so-called coalition configuration problem, in which any company can collaborate in more than one coalition. This is more general than the classic coalition structure problem, where a company must belong to only one coalition. We develop two approaches for coalition configuration in transportation. One is area-driven, which assumes the whole territory is divided into areas and then finds coalitions within each area by integer linear models. The other approach consists of a mixed integer linear programming model that embeds the coalition configuration in the transportation problem. Our motivation comes from a real world case in the forest fuels industry in Sweden, involving 27 companies, 200,000 transports, and 6 million tonnes of forest biomass, equivalent to 17 terawatt hours of energy consumption. Collaborative transportation renders about 8% of potential cost savings in this case, and may also help to increase the use of bioenergy. The coalition configuration increases by about 2.5% the savings obtained by the coalition structure and is competitive with the savings of the grand coalition.
We present a mathematical programming model for the combined vehicle routing and scheduling problem with time windows and additional temporal constraints. The temporal constraints allow for imposing ...pairwise synchronization and pairwise temporal precedence between customer visits, independently of the vehicles. We describe some real world problems where in the literature the temporal constraints are usually remarkably simplified in the solution process, even though these constraints may significantly improve the solution quality and/or usefulness. We also propose an optimization based heuristic to solve real size instances. The results of numerical experiments substantiate the importance of the temporal constraints in the solution approach. We also make a computational study by comparing a direct use of a commercial solver against the proposed heuristic, where the latter approach can find high quality solutions within specific time limits.
In today's competitive environment, most companies tend to adopt a hybrid manufacturing strategy to provide more reliable services to a wide range of customers. Based on a real-world case study, we ...investigate a customer-wise production-inventory-distribution system in a multi-level supply chain. Within this system, at a tactical planning level, the decision concerning the production strategies including make to stock (MTS), make to order (MTO), or vendor managed inventory (VMI) strategy, to choose for each customer is made, and then at the operational planning level, the production, inventory, and distribution activities are coordinated according to the strategy assigned to the customers. The objective is to optimize the total cost while the VMI customers are timely satisfied and the target service level for MTO customers is respected. Furthermore, the purchase acceptance rate for MTS customers can be controlled to enhance capacity utilization. We develop a rolling horizon planning approach to deal with the dynamics of customers' demands under different forecasting scenarios. We perform numerical experiments under both static and rolling horizons based on adapted data from a real-world application from a Canadian pulp and paper industry. The results reveal that customers placing smaller orders are classified within the VMI strategy to mitigate potential delays. Conversely, MTS customers are predominantly characterized by larger order quantities. A sensitivity analysis of key problem parameters demonstrates that the backorder cost for MTO customers can effectively influence the strategy allocation. Moreover, our results underscore the notable influence of sales prices on the distribution of customers among strategies.
•We consider a multi-level multi-product production-inventory-distribution system.•We study customer-wise mixed MTO, MTS, and VMI production strategies with a variety of customers.•The service level for MTO customers is considered.•The acceptance rate of MTS customers can be controlled.•We propose a rolling horizon replanning approach to manage dynamic updates on customers' demands.
Bioenergy is becoming a more important energy source. An important bioenergy assortment in Sweden is given by primary forest fuels. These account for about 14% of the biofuels or about 4% of Sweden's ...total energy. There are large volumes of forest fuel available. However, it is a low-value commodity and it is very sensitive to logistic cost to make it profitable. In this article, we analyse alternatives to lower the logistic costs. This includes the scheduling of the harvest and chipping operations in relation to transportation, delivered mix of assortments to customers and collaboration. We study these alternatives in a case that accounts for all operations in Sweden, involving 200,000 registered transports of about 6.1 million tons of forest biomass, equivalent to 17.4 TWh of energy consumption. We define a number of instances for these alternatives and formulate an optimization model based on linear programming. The solution is obtained by using a decision support system. We identify savings potential of about 22% from changing the operations. These savings can have a large impact on the industry and, more importantly, increase the use of bioenergy. We also test cost allocation methods to spread the savings based on cooperative game theory concepts.
•A country-wide study of the forest fuel transports in Sweden is done.•It involves 200,000 transports of 6.1 million ton of biomass equivalent to 17.4 TWh.•Efficient logistic is crucial to make forest fuel a competitive source of bioenergy.•Up to 22% savings are found by better schedules, assortments mix and collaboration.•Savings can have large impact on the industry and increase the use of bioenergy.
•Coordination can reduce the negative impact of supply uncertainty in forestry.•Not all sawmills benefit equally from coordination mechanisms.•Coordinating only the demand does not significantly ...improve the network.•Networks coordinating their supply are more stable in the face of uncertainty.•Coordinated network can answer the overall demand without backordered product.
In natural resource sectors such as forestry, supply is subject to yield uncertainty, which can make planning decisions a challenge. A common way of dealing with uncertainty is to coordinate the decisions so all units in a network can better prepare for unpredicted events. This can generate plans that are more robust and reduce the negative impacts of uncertainty. The objective of this study is to evaluate the benefits of including coordination mechanisms in a forest supply chain to better face yield uncertainty. First, a stochastic program is developed to simulate a sawmill production planning decision process, taking wood supply uncertainty into account. Based on this model, six coordination mechanisms are proposed to help reduce the impact of an uncertain wood supply. The impact of uncertainty is measured using the individual transportation cost of each sawmill, the overall network cost, the cost for replanning operations, the volume of extra resources needed, backorders, and the prescribed wood supply from forest sites to sawmills. Historical data from a partnering company in the province of Quebec, Canada, are used to quantify the current level of uncertainty. Compared to the typical strategy of Fixed Supply and Fixed Demand, the Free Supply with Free Demand mechanism generates plans with more stability, offering a 64% reduction in transportation cost, and a reduction of 84 % in the volume of extra resources to be acquired outside the regular sources at a higher cost to prevent production shortage.
Involving stakeholders in the decision-making process can be very complex and time consuming. Decision theater (DT), which enables the combination of visualization and decision modeling capabilities ...together with human capacity of insight and interaction, is proposed for addressing this challenging problem in the forest sector. A generic framework for designing DTs to support participatory planning in the forest sector is proposed. To enable DT implementation and support decision-making in the DT in the province of Québec, Canada, the conceptual design of a decision-support system called Forest Community-DSS (FC-DSS) has been developed. Implementing FC-DSS along with other technologies in a DT environment can contribute to engage the stakeholders in the decision-making process by increasing participation frequency, collecting more inputs from the stakeholders, supporting the development and evaluation of alternative options and the selection of preferred alternatives. A DT-based collaboration approach would contribute to address the multiple issues of the stakeholders involved in participatory planning in Québec. Other Canadian provinces and other countries facing similar issues can benefit from the proposed approach.
Improving productivity in forest logging operations while reducing negative impact on soil and streams has gained increasing attention. Positioning primary extraction routes is crucial in these ...efforts, as it has a huge impact on efficient and sustainable forwarder passages. To minimize the total forwarding distance and avoid steep terrain and impact on soil and water, we developed a decision support system, including a detailed optimization model and solution method. The main source of information consisted of a detailed digital terrain model, depth-to-water maps, and forest volume density. The information was supplemented with the extent of the stand, position of the landing(s), nature and culture conservation sites, and any known unavoidable crossings in the terrain (e.g., streams). Because fast solution time was a critical requirement, we developed a decomposition method based on Lagrangian relaxation. The system was evaluated in two case studies in Sweden. In the first case, the optimization model performance was analyzed at 30 final harvesting sites. In the second case, experienced forest company staff evaluated the primary extraction routes at 19 harvest sites in operational conditions. The results indicated that the model allowed for faster planning, shorter driving distances, and the potential to reduce negative impact on soil and water.
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