Showing papers in "Logistics Research in 2012"
TL;DR: The evolution of green supply chain research is traced, the past and current research efforts to develop a viablegreen supply chain strategy are synthesized, and promising future research themes related to this strategy are proposed.
Abstract: In the past several decades, great strides have been made to incorporate the ethical and environmental responsibilities into the core culture of today’s business world. With the increased attention paid to such responsibilities, a growing number of firms have explored “greening” (environmental-friendly) initiatives as their competitive strategic weapons. This paper traces the evolution of green supply chain research, synthesizes the past and current research efforts to develop a viable green supply chain strategy, and then proposes promising future research themes related to this strategy.
229 citations
TL;DR: A conceptual framework for the analysis of relationships between agile and resilient approaches, supply chain competitiveness and performance is proposed and operational and economic performance measures are proposed to facilitate the monitoring of the influence of these practices on supply chain performance.
Abstract: Supply chain management must adopt different and more innovative strategies that support a better response to customer needs in an uncertain environment. Supply chains must be more agile and be more capable of coping with disturbances, meaning that supply chains must be more resilient. The simultaneous deployment of agile and resilient approaches will enhance supply chain performance and competitiveness. Accordingly, the main objective of this paper is to propose a conceptual framework for the analysis of relationships between agile and resilient approaches, supply chain competitiveness and performance. Operational and economic performance measures are proposed to facilitate the monitoring of the influence of these practices on supply chain performance. The influence of the proposed agile and resilient practices on supply chain competitiveness is also examined in terms of time to market, product quality and customer service.
198 citations
TL;DR: A compact review of vehicle routing literature and an overview of the results of a recent study of commercial vehicle routing software systems with respect to the problem features these systems are able to handle and the solution methods the systems use for automatic generation of vehicle routes are presented.
Abstract: The contribution of this paper is a comparison of the state of the art of scientific research on and commercial software for modelling and solving vehicle routing problems. To this end, the paper presents a compact review of vehicle routing literature and an overview of the results of a recent study of commercial vehicle routing software systems with respect to the problem features these systems are able to handle and the solution methods the systems use for automatic generation of vehicle routes. In this way, existing application and research gaps are identified.
95 citations
TL;DR: The purpose of this paper is to specify the main trends, issues, and sensitive topics that characterize the behavior and performance of these production systems.
Abstract: During the last three decades, the economic landscape has abandoned its local characteristics and evolved into a global and highly competitive economy. The market demands toward high product variety, the low human labor costs in specific locations, the evolution of Information and Communication Technologies, and specific social and political forces are the principal reasons toward globalization. The main trend currently outlining the development of manufacturing paradigms is the ever-increasing tendency in the direction of decentralization of manufacturing functions toward decentralized entities. This has caused a fundamental reorganization process of the manufacturing organizations in order to cope with this trend. Several critical issues rise in the control and management of such organizations. These criticalities are further compounded by the need to achieve mass customization of industrial products, as this greatly complicates the manufacturing and supply activities. Moreover, the modalities for the configuration and implementation of each of the distributed manufacturing typologies are identified. The purpose of this paper is to specify the main trends, issues, and sensitive topics that characterize the behavior and performance of these production systems. Based on this review, a discussion over existing production concepts is performed.
83 citations
TL;DR: In this paper, a novel decision-making approach is proposed for supporting the process of configuring a DMN from a holistic perspective, taking into account production, transportation and time constraints as well as multiple criteria such as time and cost.
Abstract: Manufacturing organizations have been attempting to improve the operation of supply networks through efficient supply chain management. Dynamic manufacturing networks (DMNs) constitute chains of diverse partners, whose operation and interaction may change in a rapid and often not predictable way. While the existing supply chain models are quite static and examine transportation modes, product changeover and production facility options with fixed suppliers and over a long period of time, the DMNs address operations and risks on a daily basis. In this paper, a novel decision-making approach is proposed for supporting the process of configuring a DMN from a holistic perspective, taking into account production, transportation and time constraints as well as multiple criteria such as time and cost.
40 citations
TL;DR: This research paper is based on an extensive literature review and aims to identify and to investigate the variables that, throughout the agricultural biomass-to-energy supply chain, give rise to the barriers that are common to most varieties of biomass.
Abstract: The role that liquid biofuels will play in future energy systems will depend on biomass-to-energy supply chain to overcome the barriers that may hinder the development and international trade, as well as a sustainable and efficient production of biomass resources. This research paper is based on an extensive literature review, and its purpose is to identify and to investigate the variables that, throughout the agricultural biomass-to-energy supply chain, give rise to the barriers that are common to most varieties of biomass. For achieving it and to assess the effects of referred barriers were used techniques of the Soft Systems methodology. Although biomass-to-energy supply chains are diverse in terms of pattern and operations, the characteristic of the barriers involved in the research provides a broad insight into the issues and challenges to define consistent strategies and interventions for overcoming them. So, this review might be useful for further research related to agricultural biomass-to-energy supply chain optimization that is needed.
29 citations
TL;DR: The impact of the oil price on the optimal degree of centralization of logistics networks through the fluctuation of transportation costs is explored and an existing dependency of the European logistics network structure limited to oil prices above 150 USD/barrel is shown.
Abstract: Logistics networks need to handle globally growing transportation volumes in cost efficient and sustainable configurations. This research explores the impact of the oil price on the optimal degree of centralization of logistics networks through the fluctuation of transportation costs. The impact of the degree of centralization on greenhouse gas emissions of transportation is evaluated. Investigations are conducted by means of a model consisting of logistics network, logistics costs, carbon dioxide emissions and an empirically determined relationship of oil price, fuel price and transportation costs. First, the dependency of transportation costs in European road transports from oil prices is derived. Then, the optimal configuration of the logistics network is determined for a range of oil prices. Sensitivity analysis on the value of traded goods is performed. Results show an existing dependency of the European logistics network structure limited to oil prices above 150 USD/barrel. Dependency on the oil price increases for high-value goods compared to low-valued goods. Carbon dioxide emissions diminish with lower centralization degree, as an effect of lower total transport distance.
28 citations
TL;DR: The results confirm that in theory intermodal line-trains can provide competitive services on short and medium transport distances in case transhipment costs are kept low and the ability to achieve higher load factors decreases the door-to-door transport costs per load unit.
Abstract: Intermodal line-trains with intermediate stops between start and end terminals are regularly advocated by intermodal transport researchers as a means to compete with all-road transport on small volumes and short distance markets. A prerequisite for line-trains are innovative transhipment technologies facilitating fast and efficient transhipments, which is likely to increase the terminal costs. The major implementation barrier of line-trains is the uncertainty regarding costs of these innovative terminals and their network benefits. The purpose of this article is to analyse the effect of terminal costs on the network performance of intermodal line-trains. The paper is based on a case study, which assesses the potential modal share for an intermodal line-train on a corridor in Sweden. The results confirm that in theory intermodal line-trains can provide competitive services on short and medium transport distances in case transhipment costs are kept low. Naturally, lower transhipment costs reduce the production costs, but of even greater importance is the ability to achieve higher load factors, which decreases the door-to-door transport costs per load unit. This opens business opportunities for operators and cost-saving potential for shippers in a market segment, which is dominated by road transport.
21 citations
TL;DR: How the greenhouse performance of a fast-moving consumer goods (FMCG) distribution network depends on several variables to set up a “CO2 network footprint” is sheds light on how different changes in logistics structures may reduce GHG without technological propulsion or use of regenerative energy.
Abstract: The assessment of greenhouse gas (GHG) emissions of supply chain activities is performed to create transparency across the supply chain and to identify emission-cutting opportunities. Literature provides several generic and case study approaches to estimate GHG emissions. But research often focuses on products. This paper sheds light on how the greenhouse performance of a fast-moving consumer goods (FMCG) distribution network depends on several (FMCG specific) variables to set up a “CO2 network footprint”. Within a quantitative computational study, the distribution network footprint of an existing FMCG manufacturer is analyzed. Three options being fundamentally able to reduce total GHG emissions are identified: number of distribution centers, performance of the engaged logistics service provider and shipment structure. First, transportation processes for the investigated FMCG manufacturer are analyzed to derive GHG emissions caused by different distribution shipments. Second, initial data are manipulated to simulate variable changes, that is, different logistics structures. Third, results are reported and analyzed to show up how different changes in logistics structures may reduce GHG, without technological propulsion or use of regenerative energy.
20 citations
TL;DR: The findings indicate that a holistic or systems approach seems to have a somewhat central role in the logistics discipline, although it seems that systems theory was more explicitly treated in the early days of the discipline, having become less visible explicitly in more recent publications.
Abstract: Systems thinking has by some been proposed as the ‘hard core’ of our discipline. Others have claimed that logistics rests on systems theory. However, glancing at how these notions are used outside ...
19 citations
TL;DR: The paper reviews the evolution of the MoS concept and existing barriers in the delivery of intermodal services to understand the expectations and concerns of the important stakeholders and recommends a suitable framework for the realisation of European MoS projects.
Abstract: Motorways of the Sea (MoS) projects, that is, the development of integrated maritime-based intermodal transport infrastructure and service networks at European scale, have been the vision of the European Commission (EC) under the European Transport Policy White Paper 2001. Although these projects have been prioritised under the Trans European transport (TEN-T) networks, they have met with limited success. Establishing MoS is complex because of its international scope and involvement of a large number of public and private stakeholders that often have conflicting objectives and goals. Presently, there is a need for EC to set clear, fair and attractive conditions to engage private stakeholders in the realisation of these projects. The paper will attempt to identify these conditions and recommend a way forward. The paper reviews the evolution of the MoS concept and existing barriers in the delivery of intermodal services to understand the expectations and concerns of the important stakeholders. Case studies of European Short Sea Shipping experiences in the different maritime corridors and elsewhere around the world are analysed to identify critical success factors and recommend a suitable framework for the realisation of European MoS projects.
TL;DR: A continuum description of the flow of product through the factory is introduced based on a partial differential equation model for the time evolution of the wip-density and the production velocity that improves the mismatch between models for transient production flows and discrete event simulations significantly compared to other clearing function approaches.
Abstract: The production planning problem, i.e. to determine the production rate of a factory in the future, requires an aggregate model for the production flow through a factory. The canonical model is the clearing function model based on the assumption that the local production rate instantaneously adjusts to the one given by the equilibrium relationship between production rate (flux) and work in progress (wip), e.g. characterized by queueing theory. We will extend current theory and modeling for transient clearing functions by introducing a continuum description of the flow of product through the factory based on a partial differential equation model for the time evolution of the wip-density and the production velocity. It is shown that such a model improves the mismatch between models for transient production flows and discrete event simulations significantly compared to other clearing function approaches.
TL;DR: An economic assessment of a multimodal transport network for single pallets, based on empirical data from two major German corporations, shows that the new intermodal transportation system has a significant impact on the shipment-size distributions changing them in favor of smaller shipments.
Abstract: This paper develops an economic assessment of a multimodal transport network for single pallets. A shipment-size choice model is estimated to calculate the shippers’ reactions and their economic benefits from that transport network. In the model, the major factor influencing logistics decisions—the balance between warehouse and storage cost—is explicitly taken into account. The functional form is deduced from the first-order condition of the minimization problem of total logistics cost. Transport cost is expressed in the form of a complex function depending on shipment size and transport distance in order to capture the effect of economies of scale in transportation. The model parameters are estimated based on empirical data from two major German corporations. Simulations show that the new intermodal transportation system has a significant impact on the shipment-size distributions changing them in favor of smaller shipments. This leads especially to significant reductions in warehouse costs. Finally, some implications of the analytical results on transport policy are provided: To foster green logistics and achieve further modal shifts from road to rail, public financial support and the regulatory framework have to enable railways to consolidate small and logistics demanding shipments at an industrial scale.
TL;DR: It is shown that control-theoretic analysis can be used to develop algorithms for determining combinations of adjustments that result in WIP regulation that is as fast-acting as possible yet non-oscillatory.
Abstract: A method is presented in this paper for coordinating multiple modes of capacity adjustment in work systems with autonomous WIP regulation with the goal of maintaining desired fundamental dynamic behavior. To prevent overcorrection of capacity, adjustments involving floaters, temporary workers, overtime, etc. need to be coordinated, and it is shown that control-theoretic analysis can be used to develop algorithms for determining combinations of adjustments that result in WIP regulation that is as fast-acting as possible yet non-oscillatory. Results of discrete event simulations in Arena, driven by industrial data, are used to illustrate the dynamic behavior of WIP regulation in an autonomous work system that incorporates such an algorithm and multiple modes of capacity adjustment.
TL;DR: An approximation model to estimate the joint carrier-receiver response to off-hour delivery policies is developed to bypass the need to use more complex approaches that require expensive data for model calibration.
Abstract: The main objective of this paper is to develop an approximation model to estimate the joint carrier-receiver response to off-hour delivery policies. The model’s main intent is to bypass the need to use more complex approaches that require expensive data for model calibration. Having access to such approximation models would make it easier for transportation agencies and metropolitan planning organizations to analyze and design off-hour deliveries programs and policies. In its first part, the paper discusses carrier-receiver interactions concerning delivery time decisions, and the conditions under which both carrier and receivers would agree to off-hour deliveries. Some of the key findings are that: the typical receivers would participate only if provided with a financial incentive that cover the costs associated with the off-hour operations; and that the off-hour delivery operation would only be profitable if a large number of receivers switch to the off-hours. The latter provides an important piece of information to support the development of the approximation model introduced in the paper. The proposed model estimates the joint market share in off-hour deliveries by computing the joint probability that all receivers in a typical tour of length M agree to off-hour deliveries, the probability that the carrier operation is profitable, and finally the joint market share. The model’s inputs are the probability that a typical receiver would participate in off-hour deliveries, the statistical distribution of tour lengths, and the probability that the carrier operation is profitable for a given number of receivers. The results indicate that the model provides the same results than other more complex methodologies for the practical range of values of receiver participation. For the high end of receiver participation (+80%) the formulation underestimates carrier participation. Because of its simplicity and practicality, the model seems to provides an excellent way to estimate participation in off-hour delivery programs.
TL;DR: There is little support for claiming that logistics is rooted in systems theory, and more evidence is found that the scope of systems theory that actually has influenced the discipline is rather narrow.
Abstract: Logistics has been said to rest on a foundation of systems theory. Recent research has however indicated that such claims merely are myths that have been passed on. These myths are in this paper pu ...
TL;DR: Some design principles of metabolic systems are summarized from the perspective of production logistics and it is explored, how these principles can serve as templates for the design of robust manufacturing systems.
Abstract: Metabolism is a fascinating natural production and distribution process. Metabolic systems can be represented as a layered network, where the input layer consists of all the nutrients in the environment (raw materials entering the production process in the cell), subsequently to be processed by a complex network of biochemical reactions (middle layer) and leading to a well-defined output pattern, optimizing, e.g., cell growth. Mathematical frameworks exploiting this layered-network representation of metabolism allow the prediction of metabolic fluxes (the cell’s ’material flow’) under diverse conditions. In combination with suitable minimal models it is possible to identify fundamental design principles and understand the efficiency and robustness of metabolic systems. Here, we summarize some design principles of metabolic systems from the perspective of production logistics and explore, how these principles can serve as templates for the design of robust manufacturing systems.
TL;DR: The proposed framework captures the technological and business basis for the integration of various elements for e-market characterization with expected outcomes and depicts an appropriate policy to develop strategies for collaborative relationships between buyer and supplier in e- market.
Abstract: While exploring buyer–supplier collaborative relationships and new procurement opportunities through optimized use of the available resources, the present work proposes a framework depicting an appropriate policy. The proposed framework captures the technological and business basis for the integration of various elements for e-market characterization with expected outcomes. E-markets as coordination structures interact between various enterprises of the semiconductor industry supply chain (SSC) through the process of bidding and pricing system. In this regard, the factors affecting e-market adoption by the participants and the impact of e-market on customer service in the SSC are explored with the objective to develop strategies for collaborative relationships between buyer(s) and supplier(s) in e-market.
TL;DR: In this paper, aspects of tour planning are included approximately into location planning for a distribution network, using a cost apportionment approach that can be used with little effort to solve problems involving up to 4,000 customers in acceptable computation time.
Abstract: In this paper, aspects of tour planning are included approximately into location planning for a distribution network, using a cost apportionment approach. This approach can be used with little effort to solve problems involving up to 4,000 customers in acceptable computation time. The developed approach is analyzed and evaluated on test instances that are based partly on real distribution data. This is performed by comparing the results of the cost apportionment approach with those of a classical location planning which does not explicitly take into account aspects of tour planning.
TL;DR: Upper and lower bounds are determined for two performance measures: the number of stock-out units and the stock- out probability per replenishment cycle, given incomplete information about the demand distribution, that is only the first two moments and the range, are known.
Abstract: New products without historical demand information or slow-moving items with little such information cause difficulties in defining inventory management policies facing demand uncertainty The classical approach using the Normal distribution for describing the random demand during lead time might lead to a degraded level of customer service But the choice for other types of distributions is also no option, so it is realistic that the full functional form of the distribution is unknown, but the decision-maker has some but not incomplete information on the demand distribution during lead time As the distribution is only partially specified, several distributions satisfy the known information Customer service measures therefore also take values in an interval between a lower and an upper bound In this paper, upper and lower bounds are determined for two performance measures: the number of stock-out units and the stock-out probability per replenishment cycle, given incomplete information about the demand distribution, that is only the first two moments and the range, are known Based on these results, the optimal inventory level given the desired maximum number of stock-out units or the desired maximum stock-out probability is calculated for the case where only the first two moments are known The results of our approach are compared to the more traditional approach where a Normal distribution of demand during lead time is assumed Comparisons with the Gamma, Uniform and symmetric triangular distribution are made Furthermore, the robustness of our bounds to uncertainty in the parameters is tested
TL;DR: Analyzing the inventory performance of German corporations between 1993 and 2005, it is found that the total inventory to sales ratio decreased in a statistically significant extent in the majority of industry sectors during the period investigated.
Abstract: This study is aimed at analyzing the difference of using fixed weight aggregate inventory to sales ratios rather than “traditional”, that is, variable weighted, aggregated inventory to sales ratios. It shows that interpretations of these ratios may be problematic because different aggregation methods are signaling different time trends under certain circumstances. Analyzing the inventory performance of German corporations between 1993 and 2005, we find that the total inventory to sales ratio decreased in a statistically significant extent in the majority of industry sectors during the period investigated. Considering the effects of using fixed aggregation weights on our results, some changes concerning significance of results occur. The additional use of fixed aggregation weights is helpful because it isolates any trends observed in the aggregated inventory to sales ratio series to fluctuations in the underlying (sub) sectors’ inventory to sales ratio, not shifts in the composition of the aggregate.
TL;DR: An approximation model to estimate the joint carrier–receiver response to off-hour delivery policies is developed to bypass the need to use more complex approaches that require expensive data for model calibration.
Abstract: The main objective of this paper is to develop an approximation model to estimate the joint carrier–receiver response to off-hour delivery policies. The model’s main intent is to bypass the need to use more complex approaches that require expensive data for model calibration. Having access to such approximation models would make it easier for transportation agencies and metropolitan planning organizations to analyze and design off-hour deliveries programs and policies. In its first part, the paper discusses carrier–receiver interactions concerning delivery time decisions and the conditions under which both carrier and receivers would agree to off-hour deliveries. Some of the key findings are that the typical receivers would participate only if provided with a financial incentive that covers the costs associated with the off-hour operations and that the carrier would find the off-hour delivery operation profitable if a large number of receivers switch to the off-hours. The latter provides an important piece of information to support the development of the approximation model introduced in the paper. The proposed model estimates the joint market share in off-hour deliveries by computing the joint probability that all receivers in a typical tour of length M agree to off-hour deliveries, the probability that the carrier operation is profitable, and finally the joint market share. The model’s inputs are the probability that a typical receiver would participate in off-hour deliveries, the statistical distribution of tour lengths, and the probability that the carrier operation is profitable for a given number of receivers. The results indicate that the model provides the same results than other more complex methodologies for the practical range of values of receiver participation. For the high end of receiver participation (+80%), the formulation underestimates carrier participation. Because of its simplicity and practicality, the model provides an excellent way to estimate participation in off-hour delivery programs.
TL;DR: A parameter mapping sonification approach on production data, which is based on human perceptual skills, and which displays the complete workflow of an order simultaneously as a multi-pitched spatial sound so that causes and impacts of high throughput times in the data set example could be identified.
Abstract: The conductor of an orchestra is able to distinguish not only between different instruments, but even among dozens of string players performing on instruments with similar sound qualities. Trained human ear not only is capable to highly differentiate between pitches and colors of sound, but also to localize the position, where the sound is coming from. This chapter presents a parameter mapping sonification approach on production data, which is based on these human perceptual skills. Representatively for other logistic parameters, throughput times of orders are sonified and allocated in a sonic space. Additionally to auditory representations of the established resource and order oriented views in logistics, a third perspective is introduced, which displays the complete workflow of an order simultaneously as a multi-pitched spatial sound. Thus, causes and impacts of high throughput times in the data set example could be identified.
TL;DR: This study proposes new trading mechanisms applied in the electricity trade and evaluates them in terms of stability and social surplus in the market and examines their validity using experiments with human subjects and multi-agent simulations.
Abstract: The Smart Grid concept has lately attracted attention because of the increase of decentralized electricity generators and the development of the information communication technology. In the smart-grid concept, mutual information exchange among suppliers and consumers can be achieved to balance and optimize the supply and demand of electricity, which is generally necessary for a grid system. Taking this background into consideration, the necessity for electricity trade by which small-scale consumers such as households buy and sell electricity is now advocated to realize further stability of the grid system. However, it is noteworthy that consumers are self-interested, which endangers the grid system stability. This study proposes new trading mechanisms applied in the electricity trade and evaluates them in terms of stability and social surplus in the market. We examine their validity using experiments with human subjects and multi-agent simulations.