Journal Articles (Peer-Reviewed)
(2023): Analyzing drivers of organic food sales - a pooled spatial data analysis for Hamburg (Germany), Plos one, 18 (10): 1-29.
Abstract: Shifting the food system to a more sustainable one requires changes on both sides of the supply chain, with the consumer playing a key role. Therefore, understanding the factors that positively correlate with increased organic food sales over time for an entire population can help guide policymakers, industry, and research to increase this transition further. Using a statistical approach, we developed a spatial pooled cross-sectional model to analyze factors that positively correlate with an increased demand for organic food sales over 20 years (1999–2019) for an entire region (the city-state of Hamburg, Germany), accounting for spatial effects through the spatial error model, spatially lagged X model, and spatial Durbin error model. The results indicated that voting behavior strongly correlated with increased organic food sales over time. Specifically, areas with a higher number of residents that voted for a political party with a core focus on environmental issues, the Greens and the Left Party in Germany. However, there is a stronger connection with the more “radical” Left Party than with the “mainstream” Green Party, which may provide evidence for the attitude-behavior gap, as Left Party supporters are very convinced of their attitudes (pro-environment) and behavior thus follows. By including time and space, this analysis is the first to summarize developments over time for a metropolitan population while accounting for spatial effects and identifying areas for targeted marketing that need further motivation to increase organic food sales.
(2023): Replenishment strategies for lost sales inventory systems of perishables under demand and lead time uncertainty, European Journal of Operational Research, 308 (2): 661-675.
Abstract: We develop an inventory control policy for perishable products considering both random demand and random lead time. We consider a B2C retail environment where excess demand is lost. The policy dynamically determines the optimal replenishment quantity under a service level constraint in every period, allowing for order-crossing, a widely disregarded characteristic in the literature. Regarding perishability, we compare the two most extreme issuing policies, first-expired-first-out (FEFO) and last-expired-first-out (LEFO), and evaluate our policy to existing inventory policies for perishables that typically ignore lead time uncertainty. We obtain several interesting findings. First, we show that ignoring lead time uncertainty and planning based on the expected lead time significantly undershoots the target service level. Even planning with the maximum lead time, under LEFO, the achieved service level would still fall considerably below the target, which the lost-sales structure can explain. On the other hand, under FEFO, the achieved service level would overshoot the target service level, which leads to unnecessary waste. Second, a more reliable lead time can significantly reduce waste, especially under LEFO. Third, our model allows us to distinguish between past, present, and future lead time uncertainty and thus to consider partial lead time information. We show the value of lead time information on outstanding orders. Fourth, we evaluate the impact of a fast but unreliable delivery option and a slow but reliable delivery option on the retailer’s average waste and ordering process. We find that the optimal choice depends on the demand characteristics.
(2022): Modelling logistics for freight transport policy analysis, Transport Policy, 124: 95.
(2022): Estimating the potential of electric mobility in commercial transport considering the availability of charging infrastructure – A behavioural model analysis for the city of Hamburg, Research in Transportation Business & Management, 43: .
Abstract: To address climate change, transport policy tries to accelerate the electrification of vehicles. The impact of policy measures taken is difficult to predict especially in areas like commercial passenger transport where few research exists. In this study we estimate the impact of higher availability of charging infrastructure on the electrification potential of vehicles used in commercial passenger transport. For Hamburg we estimate that the electrification potential could increase by about 35%. We base this analysis on a company survey on vehicle usage patterns in commercial passenger transport and a ranked choice model to quantify the relationship between company sectors and tour patterns. This enables us to estimate the impact on electrification potential for overall Hamburg. The methodological contribution of this paper is to demonstrate a statistically viable approach to extrapolate insights from a behavioural survey to an overall region in the context of commercial passenger transport.
(2022): Editorial themed volume “Challenges and solutions for current freight transport and logistics”, Research in Transportation Business & Management, 44: .
Abstract: Freight transport and logistics are the backbone for business and society. This becomes especially obvious in times of crisis such as the Corona crisis or the war in Ukraine. While necessary, applied research in this area is particularly difficult since data access is limited, and heterogeneity of players and problems is high. These might be the reasons why less research has been conducted compared to neighboring fields such as passenger transport. This Themed Volume has brought together multiple new contributions in the field of freight transport and logistics. The Volume is multidisciplinary with articles using different methodologies including empirical work, statistical analysis, simulation, or optimization. Many articles originate from contributions to the 2019 European Transport Conference (ETC). After being selected they went through a thorough review process together with other papers submitted to this Themed Volume. The review process for the Themed Volume took place over the period 2020 to 2022. The papers cover multiple domains and include almost all modes of transport. Especially remarkable are four papers in the domain of rail freight, an area in which there is a dearth of papers. A number of articles cover two of the current big topics: new technologies and sustainability. This Themed Volume also includes contributions in “classical” topics of freight transport and logistics namely transport planning, carrier and location choice. The Themed Volume comprises 16 articles. Nine of the articles take a mcro-perspective, looking at problems and analysis at organisational level. The other seven articles take a macro-perspective, detailing transport system observations of relevance for policy decisions.
(2020): An ETA Prediction Model for Intermodal Transport Networks Based on Machine Learning, Business & Information Systems Engineering: .
Abstract: Transparency in transport processes is becoming increasingly important for transport companies to improve internal processes and to be able to compete for customers. One important element to increase transparency is reliable, up-to-date and accurate arrival time prediction, commonly referred to as estimated time of arrival (ETA). ETAs are not easy to determine, especially for intermodal freight transports, in which freight is transported in an intermodal container, using multiple modes of transportation. This computational study describes the structure of an ETA prediction model for intermodal freight transport networks (IFTN), in which schedule-based and non-schedule-based transports are combined, based on machine learning (ML). For each leg of the intermodal freight transport, an individual ML prediction model is developed and trained using the corresponding historical transport data and external data. The research presented in this study shows that the ML approach produces reliable ETA predictions for intermodal freight transport. These predictions comprise processing times at logistics nodes such as inland terminals and transport times on road and rail. Consequently, the outcome of this research allows decision makers to proactively communicate disruption effects to actors along the intermodal transportation chain. These actors can then initiate measures to counteract potential critical delays at subsequent stages of transport. This approach leads to increased process efficiency for all actors in the realization of complex transport operations and thus has a positive effect on the resilience and profitability of IFTNs.
(2020): A Gravity-Based Food Flow Model to Identify the Source of Foodborne Disease Outbreaks, International journal of environmental research and public health, 17 (2): 444.
Abstract: Computational traceback methodologies are important tools for investigations of widespread foodborne disease outbreaks as they assist investigators to determine the causative outbreak location and food item. In modeling the entire food supply chain from farm to fork, however, these methodologies have paid little attention to consumer behavior and mobility, instead making the simplifying assumption that consumers shop in the area adjacent to their home location. This paper aims to fill this gap by introducing a gravity-based approach to model food-flows from supermarkets to consumers and demonstrating how models of consumer shopping behavior can be used to improve computational methodologies to infer the source of an outbreak of foodborne disease. To demonstrate our approach, we develop and calibrate a gravity model of German retail shopping behavior at the postal-code level. Modeling results show that on average about 70 percent of all groceries are sourced from non-home zip codes. The value of considering shopping behavior in computational approaches for inferring the source of an outbreak is illustrated through an application example to identify a retail brand source of an outbreak. We demonstrate a significant increase in the accuracy of a network-theoretic source estimator for the outbreak source when the gravity model is included in the food supply network compared with the baseline case when contaminated individuals are assumed to shop only in their home location. Our approach illustrates how gravity models can enrich computational inference models for identifying the source (retail brand, food item, location) of an outbreak of foodborne disease. More broadly, results show how gravity models can contribute to computational approaches to model consumer shopping interactions relating to retail food environments, nutrition, and public health.
(2019): Dynamic freight flow modelling for risk evaluation in food supply, Transportation Research Part E: Logistics and Transportation Review, 121: 4-22.
Abstract: This paper presents a calibrated dynamic multi-scale multi-regional input–output (MSMRIO) model of the German food supply system based on real data. The model comprises 51 commodity groups from farm to fork differentiating three different temperature ranges as well as living animals. Spatially, it works on an aggregate level of 402 regions within Germany as well as its 50 most important trading nations. It determines the commodity flows and the additionally needed transport capacity in case of disruptions. Showing how changes in production, inventories, sourcing, and consumption affect commodity flows, the model uncovers vulnerabilities and makes risk evaluation possible.
(2019): An inventory management approximation for estimating aggregated regional food stock levels, International Journal of Production Research, 175 (1): 1-17.
Abstract: Food is an important resource in disaster management, and food stock levels hold significance for disaster mitigation research and practice. The presence or absence of food stocks is a vulnerability indicator of a region. A large part of overall food stock, before a disaster strikes, is held by private companies (retailers, wholesalers and food producers). However, there is little-to-no information on the food stock levels of commercial companies, and no approach exists to derive such information. We develop an approximation model based on essential inventory management principles and available data sources to estimate aggregated food stock levels in supply networks. The model is applied in a case example that features dairy product stock levels in the German state of Saxonia. The resulting overall stock levels are normalised, and their usability is showcased in a simple vulnerability analysis. Disaster managers are provided with a model that can be used estimate otherwise unavailable data and facilitates investigations into the regional resilience of an area. The limitations of our study are based on the aggregated nature of the supply network structure and data usage (i.e. in the model, we do not consider any seasonality or trend effects).
(2019): Locating the source of large-scale outbreaks of foodborne disease, Journal of The Royal Society Interface, 16 (151): .
Abstract: In today’s globally interconnected food system, outbreaks of foodborne disease can spread widely and cause considerable impact on public health. We study the problem of identifying the source of emerging large-scale outbreaks of foodborne disease; a crucial step in mitigating their proliferation. To solve the source identification problem, we formulate a probabilistic model of the contamination diffusion process as a random walk on a network and derive the maximum-likelihood estimator for the source location. By modelling the transmission process as a random walk, we are able to develop a novel, computationally tractable solution that accounts for all possible paths of travel through the network. This is in contrast to existing approaches to network source identification, which assume that the contamination travels along either the shortest or highest probability paths. We demonstrate the benefits of the multiple-paths approach through application to different network topologies, including stylized models of food supply network structure and real data from the 2011 Shiga toxin-producing Escherichia coli outbreak in Germany. We show significant improvements in accuracy and reliability compared with the relevant state-of-the-art approach to source identification. Beyond foodborne disease, these methods should find application in identifying the source of spread in network-based diffusion processes more generally, including in networks not well approximated by tree-like structure.
(2019): Can Regional Organic Agriculture Feed the Regional Community? A Case Study for Hamburg and North Germany, Ecological Economics, 164 (106342): .
Abstract: We compute degrees of food self-sufficiency for regions in North Germany with the city state of Hamburg at the centre, given different diets (the German average diet versus increasing substitution of legumes for meat) and production methods (conventional versus organic). Triangulating data of statistical databases, literature, and our own collection, we compute land footprints per capita and multiply by regional populations. Our findings indicate that there is great potential to feed the regional community surrounding Hamburg solely with regionally, organically grown foods, but this result depends on (1) composition of diets — specifically, the per capita meat consumption – and (2) agricultural area available in the defined region. On the basis of simplifying assumptions, the computation indicates an approximation of what is possible.
(2019): Modelling change in supply-chain-structures and its effect on freight transport demand, Transportation Research Part E: Logistics and Transportation Review, 121: 23-42.
Abstract: The paper introduces a model to determine possible impacts of changes in supply chain structures on freight transport demand. Examples are centralisation or vertical (des)integration within supply chains. The model first generates a population of establishments and commodity flows in space which is then manipulated according to different scenarios. It uses methods from transport planning and optimisation as well as scenario technique. To demonstrate its applicability a centralisation in food supply chain structures in Germany is analysed. The results show that a more educated discussion is needed for such changes since the range of possible impacts is large.
(2019): Supply chain elements in freight transport modelling, Transportation Research Part E: Logistics and Transportation Review, 121: 1-3.
Abstract: This editorial introduces the papers of a special issue of the journal on freight transport modelling. Together, 9 papers present recent advances in 3 key areas of descriptive and predictive freight modelling: activity chaining, joint modelling of choices and segmentation of users. Next to a methodological contribution in one of these 3 areas, several papers also present empirical findings that are of broader relevance for different choice problems, industries and countries.
(2016): Opportunities of sectoral freight transport demand modelling, Case Studies on Transport Policy, 4 (1): 9-12.
Abstract: Abstract This paper discusses the opportunities of sectoral freight transport demand models. The work is based on literature and insights from interdisciplinary research in the field of production, logistics and transport. First, current and future factors influencing freight transport are discussed. Next, a brief summary of the traditional transport modelling approach and recent extensions and adaptations of freight transport models is given. As interdisciplinary research has shown, the impact of the identified factors on the development of freight transport is strongly dependent on the sector under investigation. As a consequence, this paper proposes the application of a sectoral modelling approach. The automotive and food sectors in Germany are used as examples to further examine the opportunities of sectoral freight transport demand models.
(2014): Simplified Modeling and Solving of Logistics Optimization Problems, International Journal of Transportation, 2 (1): 33-52.
Abstract: Logistics optimization problems are often complex (NP - hard). Especially for large problem scopes in logistics and new agent-based freight transport models which have to solve these problems for many agents, simplifying modelling and solving procedures are necessary in order to reduce the level of complexity. Due to the variety of existing approaches and the specifics of each problem it is often difficult to find an appropriate method. This paper seeks to facilitate this process as it identifies ‘meta’ heuristics within literature, i.e. abstract courses of action that, when adapted, have proven successful in various problems. It presents a classification of general simplification principles that are useful for reducing the complexity of logistics problems, in order to facilitate understanding between academics and practice. The derivation of the related principles is based on the examination of five problems in logistics literature: facility location, distribution system, lot size, bin packing, and vehicle routing.
(2012): Generation of logistics networks in freight transportation models, Transportation, 39 (6): 1335-1351.
Abstract: This article analyzes the concept of logistics networks in the context of behavioral freight transport modeling. Starting from the basic definition of networks, the different perceptions of networks in transportation science and logistics are worked out. The micro‐macro gap, as a main challenge in freight transport modeling, is explained by the existence of logistics networks on a meso level. A taxonomy of modeling methods dealing with logistics networks is defined, based on two characteristics: the changeability of networks within models (fixed, partially variable and variable networks) and the form of cost functions mapped (economies of scale, constant average cost, and diseconomies of scale). For each category, different possible modeling methods and their application in existing freight transport models are discussed. A special focus is placed on methodologies and models that map variable networks.
Journal Articles (Professional)
(2018): Travel and logistics: data drives the race for customers, McKinsey&Company: .
(2016): Empfehlungen zur Modellierung des Wirtschaftsverkehrs, Straßenverkehrstechnik, 10: .
Abstract: Die Modellierung des Wirtschaftsverkehrs gewinnt aufgrund der aktuellen Anforderungen und Fragestellungen zunehmend an Bedeutung. Daher werden in der FGSV parallel zur Entwicklung entsprechender Regelwerke und Empfehlungen für den Personenverkehr auch der aktuelle Stand der Technik zur Modellierung des Wirtschaftsverkehrs beleuchtet sowie Empfehlungen und Hinweise zu seiner Modellierung entwickelt. Zunächst werden dazu die Fragestellungen analysiert. Im Anschluss daran werden die Unterschiede in der Modellierung des Wirtschaftsverkehrs zum Personenverkehr erläutert. Dabei werden der Modellaufbau, die verwendeten Modellierungsmethoden sowie eine Auswahl von Softwarewerkzeugen vorgestellt und analysiert. Nachdem die wesentlichen Datenquellen für Wirtschaftsverkehrsmodelle benannt wurden, werden abschließend einige Beispiele für Wirtschaftsverkehrsmodelle dargestellt. Due to increasing requirements the modelling of commercial traffic receives more and more attention. The German Road and Transportation Research Association (FGSV) compiled the state-of-practice of modelling transport and included, thus, specific recommendations for commercial transport. This article provides an overview of commercial transport modelling issues: First, the different purposes of modelling commercial transport are listed. In the next step the difference between private and commercial transport modelling is discussed. This section is subdivided into model architecture and modelling methods. An overview of software products is enclosed as well as a description of the relevant input data. The article closes with some examples for commercial transport models.
(2016): Versorgung in Krisenzeiten sichern, Lebensmittelzeitung, 14. Oktober: 53.
Books
(2020): Smart Event Forecast for Seaports (SMECS): Endbericht Forschungsprojekt..
Abstract: Im SMECS-Projekt wurde durch Anwendung von KI-Verfahren des Maschinellen Lernens ein IT-System entwickelt, welches dynamisch die Ankunftszeit (ETA) von Containertransporten im intermodalen Vorlauf der maritimen Transportkette prognostiziert. Das System erkennt proaktiv Konflikte bei der Einhaltung des geplanten Transportverlaufes vom Warenversender bis zum Seehafen und befähigt die Anwender zu einer zielgerichteten und effizienten Durchführung geeigneter Störungsmaßnahmen durch die Vorgabe von akteursspezifischen Handlungsempfehlungen.
(2016): Quantitative Modellierung der Lebensmittelversorgung in Deutschland des Verbundprojektes SEAK: Endbericht Forschungsprojekt..
Abstract: Die zuverlässige Versorgung mit Lebensmitteln ist ein Grundbedürfnis der Bevölkerung. Ein effizientes Risikomanagement zur Vermeidung von Versorgungsengpässen ist daher sowohl von staatlicher als auch privatwirtschaftlicher Seite erforderlich. Zu dieser übergeordneten Zielstellung, die Sicherheit der Lebensmittelversorgung für Bürgerinnen und Bürger zu erhöhen, liefert das Verbundprojekt einen Beitrag durch eine fokussierte Untersuchung hinsichtlich möglicher Versorgungsengpässe, um das Management derartiger Lagen zu verbessern. Konkret ergab sich für das Projekt SEAK daraus die Aufgabe, Möglichkeiten der Entscheidungsunterstützung zur Sicherstellung der Lebensmittelversorgung zu erforschen, um geeignete Instrumente für Unternehmen und Behörden zur Verfügung zu stellen.
(2010): Simulation of logistics in food retailing for freight transportation analysis (Dissertation), Karlsruher Institut für Technologie (KIT): Karlsruhe, Germany..
Abstract: The study contributes to fill the gap between freight transportation analysis and logistic research. It describes the model SYNTRADE, a simulation model that reproduces logistic structures in the German food retailing sector. Logistic decisions and their interdependencies are simulated based on heuristics from the field of logistic optimization. The model provides the possibility to analyze changes in logistics and freight transport demand on a company, as well as on an overall sector level. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000020602
(2004): Voraussetzungen für eine Aktivitäten-basierte Güterverkehrsmodellierung (Diploma Thesis), Karlsruher Institut für Technologie (KIT): Karlsruhe, Germany..
Conference Proceedings
: An Approach to Analyze the Intermodal Rail Transport Market in Germany, in: Schmidt, Thorsten, Kai Furmans, Bernd Hellingrath, René Koster, Anne Lange and Hartmut Zadek (ed.): 2023 International Scientific Symposium on Logistics : Conference Volume, Bundesvereinigung Logistik (BVL) e.V., Berlin, 95-100.
Abstract: This study aims to provide a complete overview of intermodal rail connections in Germany and identify the market players involved in their operation. The lack of a comprehensive overview is attributed to the difficulty of summarizing empirical data of intermodal rail transport, combined with the many rapid changes in the dynamic open market. The study uses a dataset compiled through online research and interviews with market players. The identified market players include intermodal operators, railway carriers, terminals, and ports.
: Analysis of the European intermodal rail freight market: European Transport Conference, .
Abstract: Motivation and literature In recent years, interest in intermodal rail transport has increased among academics. This is mainly triggered by the European Union's ambition to decarbonize transport. The ambitions are described in the white paper on transport. One of the main goals is to shift thirty per cent of long-distance road freight over 300 kilometers to rail or waterborne transport by 2030 and more than fifty per cent by 2050 (European Commission, 2011). Intermodal transport plays an important role in execution. Several case studies have been done on intermodal transport within a specific region (Frémont and Franc, 2010 and Arnold et al., 2004), but only one empirical study is available with a holistic overview of intermodal transport in Europe. Because the transport market is an open market with many continuous changes in transport flows, the study is not up-to-date anymore. In addition, NUTS1-level statistics are available from 2020 on intermodal rail transport (UIC, 2020). However, there is a lack of data at NUTS2 level and NUTS3 level for microanalysis. In this study, we update the study by de Langen (2017) and try to fill the gap at NUTS2 and NUTS3 levels. Objective The main objective of this research is to propose a market overview of all intermodal rail connections in Europe on NUTS2-level and NUTS3-level as of March 2023. The market overview and dataset can serve as a starting point to define new public statistics on multimodal transport and for research by other scholars. Outline and structure The first step in the market-analysis is to analyze the market structure focused on the possible roles within the intermodal transport environment. For this purpose, 10 to 15 interviews are conducted with various market players in the intermodal transport environment. Based on the structure and the interviews, market players can be identified to map the market. In the second step, it is first determined which information is used to create a database with all rail connections of intermodal transport. Subsequently, it is examined which sources are publicly available that meet the criteria. This determines which measurable characteristics there are to build a database. The sources are described and it is explained how the information can be used. The third step then explains how the data can be verified using public information from railway network operators in individual countries in Europe and using secondary sources. The results section provides a broad overview of the market structure and available connections. The results show characteristics of the entire market and a division into market segments. A geographical analysis om NUTS3 level and market shares of the identified market players by operator, rail carriers and terminal operators are provided. Subsequently, the results and limitations of the study are discussed. This leads to recommendations for the use of the data and for further research. Finally, the database with 1000+ datasets (intermodal connections), including characteristics, will be published in the appendix.
: Realization of ETA Predictions for Intermodal Logistics Networks using Artificial Intelligence, in: Clausen, Uwe, Sven Langkau and Felix Kreuz (ed.): Advances in Production, Logistics and Traffic: Proceedings of the 4th Interdisciplinary Conference on Production Logistics and Traffic, Springer International Publishing: Cham, 155-176.
Abstract: Intermodal logistics networks such as the maritime transport chain require a precise interaction of numerous actors. However, due to their complexity, the closely interlinked processes are highly susceptible to disruptions. Companies are constantly faced with the challenge of dealing effectively and efficiently with disruptions and resultant delays. At the same time, they are confronted with increasing logistical requirements related to higher quality and flexibility demands of customers (Straube et al. 2013). Supply chains are becoming increasingly vulnerable, due to the associated necessity to cope with increasing volatility while simultaneously reducing risk buffers in processes as a result of rising cost pressure. Combined with ongoing changes due to digitization, this situation contributes significantly to an increasing need for improved information transparency among companies and their customers.
: A Gravity-Based Approach to Connect Food Retailers with Consumers for Traceback Models of Food-Borne Diseases, in: Cherifi, Hocine, Sabrina Gaito, José Fernendo Mendes, Esteban Moro and Luis Mateus Rocha (ed.): Complex networks and their applications VIII: Proceedings of the Eighth International Conference on Complex Networks and Their Applications COMPLEX NETWORKS 2019882, , 363-375.
Abstract: Computational traceback models are important tools for investigations of widespread food-borne disease outbreaks as they help to determine the causative outbreak location and food item. In an attempt to understand the entire food supply chain from farm to fork, however, these models have paid little attention to consumer behavior and mobility, instead making the simplifying assumption that consumers shop in their home location. This paper aims to fill this gap by modelling food-flows from supermarkets to consumers in a large-scale gravity model for Hesse, Germany. Modelling results show that on average, groceries are sourced from two to four postal zones with half of all goods originating from non-home postal zones. The results contribute to a better understanding of the last link in the food supply chain. In practice, this allows investigators to relate reported outbreak cases with sourcing zones and respective food-retailers. The inclusion of this information into existing models is expected to improve their performance.
: Success factors for financial sustainability of toll road projects: empirical evidence from China, in: Ulengin, Fusun, Gopal Patil, Ozay Ozaydin, Lóránt Tavasszy and Ashish Verma (ed.): Proceedings of the WCTRS Conference on Transportation Research 2019, Transportation Research Procedia, , 1848-1860.
Abstract: Toll roads are believed to have a high ability to attract private investment since they are able to recover directly the costs of their operation and construction through toll charges. However, toll road development can only be attractive to investors and lenders if the long-term sustainability is achieved. This paper identifies and discusses various issues that government and project developers have to deal with from selected case studies. The seven selected toll road projects are priority sections of the National Trunk Highway System (NTHS) and located in strategic provinces in China. The issues examined are related to policy support, regional development, the fund-raising model, project development and the financial structure. This study reveals critical success factors to achieve sustainable toll road projects in the planning stage and to control and enhance the financial sustainability in the executing stage.
: Locations of Logistics Service Providers in Germany - The basis for a new freight transport generation model., in: Ulengin, Fusun, Keping Li and Manfred Boltze (ed.): Selected Proceedings of the WCTRS Conference on Transportation Research 2016, , 1061-1074.
Abstract: Integrating the decisions and the behavior of Logistics Service Providers (LSPs) into freight transport models is essential to be capable of accurately describing future developments in freight transport systems. Knowledge on the spatial distribution patterns of LSP locations, e.g. to represent network routing of shipments more accurately, is of paramount importance. Moreover, attributes characterizing the LSP locations are helpful to relate them to traffic generation. Therefore, the objective of this paper is to present intermediate results of an empirical study on LSP locations in Germany. Drawing on these findings, the freight generated by German less than truckload networks is estimated on an aggregate level. These findings shed some light on the spatial and structural patterns of the locations allocable to the German logistics sector and the freight transport it generates. These insights are highly relevant for freight transport and land use planning policies.
: Legalizing the illegal parking, a solution for parking scarcity in developing countries, in: Ulengin, Fusun, Keping Li and Manfred Boltze (ed.): Selected Proceedings of the WCTRS Conference on Transportation Research 2016, , 4950-4965.
Abstract: The objective of this study is to understand how and to what extend illegal parking should be legalized, giving the benefit for parking users, urban planning, and transport planning. From literature, the policies and theories based on the lessons from other countries have provided the basis that can be applied in investigating a new parking management paradigm. Empirical surveys are conducted to examine the parking conditions, parking user’s behavior and the consequence of illegal parking spaces in the core city center in Hanoi, Vietnam. Then, the requirements of para-parking (legalization of illegal parking spaces) are formulated including the change process that involves parking authorities, parking operators, and parking users. An in-depth analyze is undertaken to look at opportunities, risks and forms of para-parking and finally a proposal for a qualitative economic impact assessment of parking facility investment is given.
: The interdisciplinary decision map - A reference model for production, logistics and traffic: TRB 94th Annual Meeting Compendium of Papers DVD, .
Abstract: Due to strong interdependencies between production, logistics and traffic, a decision in one of these fields has impacts on the others. However, decision makers in and around today’s supply chains rarely consider effects of their decisions on other participants of the supply chain or the traffic system. Thus, a tool for decision support, which clearly illustrates the variety of impacts of a decision, is highly desirable. Accordingly, this paper presents a reference model in the context of production, logistics and traffic, called Interdisciplinary Decision Map (IDM). The IDM allows for describing and analyzing interdisciplinary impacts of decisions across the disciplines. Thus, it can serve as decision support tool for decision makers out of the considered domains. The IDM’s applicability is demonstrated by using it to analyze selected impacts of an heavy goods vehicles (HGV) toll’s introduction on production, logistics and traffic.
: Modelling Dynamic Commodity Flows Using the Example of the German Food Supply Sector, in: Gammelgaard, Britta, Günter Prockl, Aseem Kinra, Jesper Aastrup, Peter Holm Andreasen, Hans-Joachim Schramm, Juliana Hsuan, Malek Malouf and Andreas Wieland (ed.): 26th Conference of the Nordic Logistics Research Network : NOFOMA 2014, Copenhagen, Denmark: June 11-13, 2014, .
: The SEAK Project: Decision Support for Managing Disruptions in Food Supply Chains, in: Thoma, Klaus (ed.): Future Security - 9th Security Research Conference, Berlin, September 16 - 18, 2014, Fraunhofer-Verl: Stuttgart, 581-584.
: Generierung der Nachfragestrukturen für die mikroskopische Simulation des städtischen Distributionsverkehrs im Lebensmittelhandel, in: Clausen, Uwe and Carina Thaller (ed.): Wirtschaftsverkehr 2013, Springer: Berlin, Heidelberg, 32-48.
Abstract: Wirtschaftsverkehrs- und City-Logistik-Modelle ermöglichen die Simulation des Verkehrsverhaltens sowie die Untersuchung und Bewertung von verschiedenen verkehrspolitischen Maßnahmen. Prominente Maßnahmen sind beispielsweise Einfahrverbote bestimmter Lkw-Typen, räumlich und zeitlich differenzierte Mautgebühren oder die Nutzung von Güterverkehrszentren. Diese Arbeit ist eingebettet in einen übergeordneten Ansatz zur mikroskopischen Modellierung des städtischen Distributionsverkehrs im Lebensmitteleinzelhandel. Neben der Verhaltensmodellierung der Entscheidungsträger sowie der physischen Simulation der Fahrzeugbewegungen liegt die große Herausforderung in der Gewinnung der Modelleingangsdaten zur Beschreibung des umfassenden Entscheidungsproblems in der Distributionslogistik. Die Ableitung dieser Daten sowie die Illustration am Beispiel eines Berlin-Szenarios ist Gegenstand des vorliegenden Aufsatzes.
: Modeling of Freight Transport Distribution in Germany – A Discussion of Traditional Distribution Models and a new Procedure for Performance Improvement: Selected Proceedings of the WCTRS Conference on Transportation Research, .
Abstract: This work aims to discuss modeling issues on solving the transport distribution problem in freight transport. The traditional distribution model – the Gravity Model – is introduced in detail with the focus on its forecasting capability of freight transport distribution. Through analyses on the base of observed and predicted data of freight transport in Germany, it is found that, compared to applying the Gravity Model, directly balancing the observed distribution from the last period using the Furness Method can generate more closer predictions to the official predictions in a planning project of the German Federal Ministry of Transport, Building and Urban Development. However, the re is a doubt about whether this Furness Method itself brings about an impact on the deterrence exponent. Based on the proposition that the Furness Method dilutes the deterrence effect of transport costs, a compensating procedure is developed in this work as a supplement to the traditional process, offering a new thinking to improve the prediction performance of distribution models.
: Decision Support for Critical Infrastructure Disruptions: An Integrated Approach to Secure Food Supply, in: Comes, Tina, Frank Friedrich, Stephen Fortier, Jutta Geldermann and Tim Müller (ed.): Proceedings of the 10th International Conference on Information Systems for Crisis Response and Management (ISCRAM), , 312-316.
Abstract: Supplies of food and water are essential in disaster management, particularly in the very early chaotic phases when demand and available resources are highly uncertain, information systems are disrupted, and communication between communities, food suppliers, retail and emergency authorities is difficult. As many actors and organisations are involved in ever more complex food supply chains, cooperation and collaboration are vital for efficient and effective disaster management. To support decision-makers facing these problems, this paper introduces a scenario-based approach that integrates simulation of disruptions in food supply chains, and qualitative expert assessment to develop consistent scenarios that show the consequences of different strategies. To choose the best individual measures for all relevant actors and to compare it with the best overall strategy approaches from multi-criteria decision analysis are used.
: A Concept for Modeling Freight Transport within Supply Networks of the Automotive Industry: Proceedings of the WCTRS Conference on Transportation Research, .
: Production, Logistics, and Traffic: A Systematic Approach to Understand Interactions: Selected Proceedings of the WCTRS Conference on Transportation Research, .
Abstract: Desicion-makers in and around today's supply chains are facing tough every day. However, when making decisions, they rarely consider what effects their desicions cause upon other participants of the supply chain or traffic management. This is mostly due to the lack of appropriate tools which help indicating the possible effects. Such tools are necessary to tackle the inherent complexity of the whole supply chain system. This paper describes how to construct and design such a tool for this interdisciplinary environment, called an Interdisciplinary Decision Map (IDM). The IDM is a powerful tool to visualise complex relationships, while at the same time retaining usability by showing relevant information only. We show how tu use a specific instance of an IDM to facilitate a better understanding to the underlying processes of other supply chain participants. The soundness of our approach is backed by findings from an interdisciplinary research project.
: Assessing the impacts of HGV tolls and transport logistics: Proceedings of the WCTRS Conference on Transportation Research, .
Abstract: In this article, basic characteristics of HGV toll systems are described. Based on that, these systems' impacts on entrepreneurial processes and resulting changes in business choices are discussed. Furthermore, a case study on hauliers' reactions on the German HGV toll is presented. The results show that the haulage industry only has to deal with marginal impacts since costs are usually passed along to the customer, this is why operational changes do not seem necessary.
: Measures of Supply Chain Risk Management: Proceedings of the 9th International Meeting on Logistics Research, .
: Identifikation von Tourtypen in Fahrzeugtagebüchern, in: Clausen, Uwe (ed.): Fachtagung Wirtschaftsverkehr 2011: Modelle - Strategien - Nachhaltigkeit, : Dortmund, 55-75.
: Transferring Methods from Social Dynamic Network Analysis to Freight Transportation: Proceedings of the 16th International Conference of Hong Kong Society for Transportation Studies, .
: Simulation of Logistic Structures in Food Retailing to Estimate Demand for Freight Transportation: Proceedings of the WCTRS Conference on Transportation Research 2010, .
: Estimation of the Benefits of Shippers from a Multi-Modal Transport Network: Selected Proceedings of the WCTRS Conference on Transportation Research 2010, .
Abstract: This paper estimates the shippers‟ reactions and their economic benefits from a multimodal transport network called LOGOTAKT. For this purpose, an econometric shipper model is being estimated in which the major factor influencing logistics decisions – the balance between warehouse and storage cost – is explicitly taken into account. The functional form is being deduced from the first order condition of Total Logistics Cost function minimization. Transport cost is expressed in form of a complex function depending on order size and the transport distance in order capture the effect of economies of scale in transportation. It is estimated based on empirical data of distribution obtained from two major German companies. Simulations show that the new multimodal transportation system has a significant impact on 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 achieve further modal shift from road to rail, public financial support and the regulatory framework must put railways into the position to consolidate shipments and to exhaust economies of scale.
: Consideration of Logistics for Policy Analysis with Freight Transport Models: Proceedings of the 9th Conference on Applied Infrastructure Research, : Berlin.
Abstract: In recent years a rising attention for logistics in politics and transport analysis can be ob-served. Therefore, freight transport models increasingly put more attention on logistics. How-ever, logistics is mostly modeled in a very simplified way and different parts of logistics are considered. Modelers have limited options to build more mature logistics models: A detailed representation of logistics requires the description of a heterogeneous economic landscape leading to very high data demand and it requires to model combinatorial logistic problems exceeding the processing capability available. Therefore a balance has to be found between mapping logistic behavior in a “reality-like” way and the need to keep the model as simple as possible. Based on conceptual frameworks on logistic choice levels and logistic structures the paper shortly reviews a selection of existing modeling approaches. This and a detailed discus-sion of two modeling experiences show future strategies in freight transport modeling to-wards finding this balance.
: Demand modeling for microscopic models in freight transport ‐ Modeling the Splitting of the flow of goods with Total Logistic Costs: Proceedings of the 11th World Conference on Transport Research Society (WCTRS), .
: Die Relation zwischen Wirtschaftsakteuren als zukünftige Bezugsgröße für mikroskopische Güterverkehrsmodelle, in: Clausen, Uwe (ed.): Wirtschaftsverkehr 2007: Modelle - Strukturen - Umsetzung, : Dortmund, 25-34.
Book Chapters
: Nutzer-und produzentenbasierte Logistik-Start-ups–Ressourcen, Strategien, Erfolge, in: Schwemmer, Martin and Patrick Seeßle (ed.): Logistik-Start-ups: Entstehung der "Neuen Logistik" aus Wissenschafts- und Unternehmenssicht: 1st ed. 2021, Springer Fachmedien Wiesbaden; Springer Gabler: Wiesbaden, 49-67.
Abstract: In diesem Kapitel unterscheiden wir zwei Arten von Start-ups in der Logistik: nutzerbasierte und produzientenbasierte Start-ups. Sehr wichtig für den Erfolg eines Start-ups ist, neben der Geschäftsidee selbst, auch der Zugang zu Ressourcen. Ziel des Kapitels ist es, nutzer- oder produzentenbasierte deutsche Logistik-Start-ups zu analysieren und für ihren Erfolg benötigte Ressourcen zu identifizieren. Dazu wurden Interviews mit 19 deutschen Logistik-Start-ups durchgeführt, auf deren Basis erste Hypothesen formuliert werden. Die Ergebnisse legen nahe, dass Innovation in deutschen Start-ups eher produzentenbasiert ist, beide Arten von Innovation (sowohl produzenten- als auch nutzerbasierte) in der Logistik aber erfolgreich sein können. In beiden Fällen scheint bei den erfolgreichen Start-ups jedoch eine enge Verknüpfung mit der Logistikindustrie vorzuliegen, ob als Zulieferer von komplementären Ressourcen oder als Kunde.
: Chapter 12 - Synthesis, in: Kourounioti, Ioanna, Lorant Tavasszy and Hanno Friedrich (ed.): Freight Transport Modeling in Emerging Countries: 1st ed., Elsevier, 253-268.
: The Network Source Location Problem in the Context of Foodborne Disease Outbreaks, in: Ghanbarnejad, F., R. Saha Roy, F. Karimi, J.-C. Delvenne and B. Mitra (ed.): Dynamics On and Of Complex Networks III: Machine Learning and Statistical Physics Approaches (available as eBook), Springer, 151-165.
Abstract: In today’s globally interconnected food system, outbreaks of foodborne disease can spread widely and cause considerable impact on public health. Food distribution is a complex system that can be seen as a network of trade flows connecting supply chain actors. Identifying the source of an outbreak of foodborne disease distributed across this network can be solved by considering this network structure and the dimensions of information it contains. The literature on the network source identification problem has grown widely in recent years covering problems in many different contexts, from contagious disease infecting a human population, to computer viruses spreading through the Internet, to rumors or trends diffusing through a social network. Much of this work has focused on studying this problem in analytically tractable frameworks, designing approaches to work on trees and extending to general network structures in an ad hoc manner. These simplified frameworks lack many features of real-world networks and problem contexts that can dramatically impact transmission dynamics, and therefore, backwards inference of the transmission process. Moreover, the features that distinguish foodborne disease in the context of source identification have not previously been studied or identified. In this article we identify these features, then provide a review of existing work on the network source identification problem, categorizing approaches according to these features. We conclude that much of the existing work cannot be implemented in the foodborne disease problem because it makes assumptions about the transmission process that are unrealistic in the context of food supply networks—that is, identifying the source of an epidemic contagion whereas foodborne contamination spreads through a transport network-mediated diffusion process, or because it requires data that is not available—complete observations of the contamination status of all nodes in the network.
: The Interdisciplinary Decision Map: A Reference Model for Production, Logistics and Traffic, in: Abele, Eberhard, Manfred Boltze and Hans-Christian Pfohl (ed.): Dynamic and Seamless Integration of Production, Logistics and Traffic: Fundamentals of Interdisciplinary Decision Support, Springer International Publishing: Cham, 31-47.
Abstract: Due to strong interdependencies between production, logistics and traffic, a decision in one of these fields has impacts on the others. However, decision-makers in and around today’s supply chains rarely consider effects of their decisions on other participants of the supply chain or the traffic system. Thus, a tool for decision support, which clearly illustrates the variety of impacts of a decision, is highly desirable. Accordingly, this chapter presents a reference model in the context of production, logistics and traffic, called Interdisciplinary Decision Map (IDM). The IDM allows for describing and analysing interdisciplinary impacts of decisions across the disciplines. Thus, it can serve as decision support tool for decision-makers out of the considered domains. The IDM’s applicability is demonstrated by using it to analyse selected impacts of an HGV toll’s introduction on production, logistics and traffic.
: Implications for Freight Transport Demand Modelling from Interdisciplinary Research: Developing a Concept for Modelling Freight Transport Within Supply Networks of the Automotive Industry, in: Abele, Eberhard, Manfred Boltze and Hans-Christian Pfohl (ed.): Dynamic and Seamless Integration of Production, Logistics and Traffic: Fundamentals of Interdisciplinary Decision Support, Springer International Publishing: Cham, 185-207.
Abstract: The freight transport system is a major determinant for the competitiveness of logistics and production activities. On the other hand, logistics and production shape freight transport demand. Therefore, freight transport demand models are needed that can capture the influence and requirements of ongoing trends in production and logistics. In this chapter, the German automotive industry is used as an example of how certain trends might influence the development of freight transport demand. Here, the impact of changes in the supply chain structure on freight transport demand is emphasised. Furthermore, data sources available on the sectoral level are discussed. Based on the insights into ongoing trends, available data and sectoral characteristics, a concept for a sectoral freight transport model for the German automotive industry is developed.
: An Inventory-Focused Analysis of German Food Supply Chains: The Case of Dairy Products, in: Clausen, Uwe, Hanno Friedrich, Carina Thaller and Christiane Geiger (ed.): Commercial Transport - Proceedings of the 2nd Interdiciplinary Conference on Production, Logistics and Traffic 2015, Springer: Cham, Switzerland, 337-347.
Abstract: This work was created as part of the research project SEAK, which looks into possible causes and consequences of food shortfalls in Germany and is moreover also aimed at developing and evaluating possible mitigation strategies for these shortfalls. For the management of shortfalls in food supply it would be, as a first step, crucial to have information on existing inventories. Making for example decisions on the reallocation of food products into regions affected by disasters is only possible if knowledge about the (regional) availability of food quantities is present in the first place. This could be considered as a necessary transparency. However, in the German food sector, it is hard to get data about the inventories kept by companies like producers, logistic service providers (LSP’s), wholesalers or retailers. This is due to the fact that usually companies are not obliged to publish this information. Moreover, this information is also considered confidential in most companies, since it would give competitors insight into their business model and processes, which are oftentimes the basis for their success. Since information concerning food inventories is not publicly available, it has to be derived in another manner. This work is aimed at providing a scientific basis for the modelling of inventories along food supply chains. More specifically, it does so for the food commodity group of dairy products. We gathered information on all available food products, but limit this particular analysis to dairy products as a showcase of our approach. First, we introduce the data set used for the analysis and the methodology applied to it. In a next step, characteristics of typical German dairy supply chains are described using practical evidence as well as literature findings. The description follows the supply chain’s structure from start to finish, downstream. In the end, concluding remarks are made and possible further research ventures are suggested.
: Freight Transport Demand Modelling – Typology of Characterizing Freight Transport Demand Models, in: Clausen, Uwe, Hanno Friedrich, Carina Thaller and Christiane Geiger (ed.): Commercial Transport - Proceedings of the 2nd Interdiciplinary Conference on Production, Logistics and Traffic 2015, Springer: Cham, Switzerland, 39-54.
Abstract: Due to the structural heterogeneity of freight transport and its long-term subordinate consideration, there have been low research activities in this field as well as low motivations to integrate this segment into transport demand models for decades. There is also no generally valid framework for freight transport modelling in comparison to passenger transport modelling. Without a common framework, it is difficult to exchange ideas between scientists and to enable an efficient communication and solid agreements between a client and a contractor of a transport modelling service. This contribution presents a typological order of characteristics of freight transport demand models which covers their internal structures and employed methods. In addition, a systematic overview of selected international freight transport demand models is given.
: Supply Chain Risk Analysis with Extended Freight Transportation Models, in: Ben-Akiva, Moshe E., Hilde Meersman and van de Voorde, E. (ed.): Freight transport modelling: 1st ed, Emerald: Bingley, UK, 218-232.
: Distribution Structures, in: Tavasszy, Lorant and Gerard de Jong (ed.): Modelling freight transport: 1st ed., Elsevier, 65-87.
Abstract: Distribution structures are important elements of the freight transportation system. Goods are routed via warehouses on their way from production to consumption. This chapter discusses drivers behind these structures, logistics decisions connected to distribution structures on the micro level, and possible modeling methodologies on the macro level. The authors show the connection between the micro and the macro level and highlight advantages of the different modeling approaches.
Case Studies
(2023): The Intermodal Case, Reference no. 623-0030-1, KLU Case Study Series, Kühne Logistics University.
Abstract: The case revolves around transport planning under difficult circumstances. The participants must schedule and coordinate the transport of a container from the South of Germany to the port of Hamburg. The transport can take place in two ways, with a total of four possible routes via direct road transport or intermodal rail transport from three different hinterland terminals. The transport routes are compared based on three criteria, (1) transport price, (2) emissions, and (3) reliability. The case contains a role play in which the participants learn the advantages and disadvantages of direct road transport compared to intermodal rail transport. For the planning process an online tool is provided. Four fixed routes are programmed into the tool. The routes consist of various transport parts with a fixed transport route, a fixed transport duration, and fixed emission values. The participants can use the tool to plan the transport by planning departure times, and planning buffers between the parts of the transport. The case is structured in such a way that all routes have advantages and disadvantages, so that it cannot be said that there is one correct answer. The case should stimulate discussion among participants.
(2021): The Railport Case, Reference no. 221-0014-1, KLU Case Study Series #4, Kühne Logistics University.
Abstract: Discussions on sustainability in freight transportation often result in the claim that more goods should be transported via rail instead of by truck. The introduction of the CO2 emission tax from 2021 onward in Germany might positively influence the economic competitiveness of the railway sector. Complete trains (direct trains from point to point) were already rather efficient and attractive before. However, single wagon networks struggle and constantly lose market share. For mixed load cargo (shipments with one to several pallets) the single wagon network is not used at all anymore. One initiative, so-called 'Railports', aim to make the latter more efficient and attractive to the market and therefore maybe help to accelerate the modal shift. In this case students should gain insights into the complexity of investment decisions in an environment of a natural monopoly, a publicly sponsored, regulated company and the threat of regulated access to properties/infrastructure with high initial investment costs. Students should identify and discuss the possibly opposing positions of society and the investor as well as the point of view of competitors. A fictive hearing in the form of a role-play should improve the students’ negotiation skills and their argumentation skills from different perspectives.