1,721,027 research outputs found
Decision support tools for developing sustainable transportation systems in the EU: A review of research needs, barriers, and trends
No full textTransportation is an indispensable activity for the socio-economic development of countries. However, it is one
of the most energy consuming and polluting activities and its environmental impact is expected to increase in the
future. As a conse- quence, there is a growing need for managing in a more efficient and sustainable manner this
sector. This paper investigates the main issues in developing sustain- able transportation systems with a focus on
the European Union, highlighting recent trends to identify the foremost research areas whose advancement will
reduce the environmental impact of this sector. Following the European Commission guidelines, three subthemes
are focused: Supply Chain Networks, intermodal transportation of freights, and passenger transportation
in urban area. Based on a literature review, each sub-theme is analyzed in terms of needs, barriers, and
recent research trends. Some contributions to accomplish the identified needs and overcome the detected barriers
are reported as baselines to address the future research agenda. The main findings fit with most of the industrialized
countries, that are expected to make more significant reductions in their environmental impact. At the
same time, by highlighting examples of good practices and identifying limits to adaptation, this work can also
support developing countries in tackling this issue
A Timed Petri Nets Model for Performance Evaluation of Intermodal Freight Transport Terminals
Full text linkThis paper presents a general modeling framework for Intermodal Freight Transport Terminals (IFTTs). The model allows simulating and evaluating the performance of such key elements of the intermodal transportation chain. Hence, it may be used by the decision maker to identify the IFTT bottlenecks, as well as to test different solutions to improve the IFTT dynamics. The proposed modeling framework is modular and based on timed Petri Nets (PNs), where places represent resources and capacities or conditions, transitions model inputs, flows, and activities into the terminal and tokens are intermodal transport units or the means on which they are transported. The model is able to represent the different types of existing IFTTs. Its effectiveness is tested first on an example from the literature and then on a real case study, the railroad inland terminal of a leading Italian intermodal logistics company, showing its ease of application. In the real case study, using the proposed formalism we test the as-is IFTT performance and evaluate alternative possible to-be improvements in order to identify and eliminate emerging criticalities in the terminal dynamics
A stochastic cross-efficiency data envelopment analysis approach for supplier selection under uncertainty
No full textThis paper addresses one of the key objectives of the supply chain strategic design phase, that is, the optimal selection of suppliers. A methodology for supplier selection under uncertainty is proposed, integrating the cross-efficiency data envelopment analysis (DEA) and Monte Carlo approach. The combination of these two techniques allows overcoming the deterministic feature of the classical cross-efficiency DEA approach. Moreover, we define an indicator of the robustness of the determined supplier ranking. The technique is able to manage the supplier selection problem considering nondeterministic input and output data. It allows the evaluation of suppliers under uncertainty, a particularly significant circumstance for the assessment of potential suppliers. The novel approach helps buyers in choosing the right partners under uncertainty and ranking suppliers upon a multiple sourcing strategy, even when considering complex evaluations with a high number of suppliers and many input and output criteria
A cross-efficiency fuzzy Data Envelopment Analysis technique for performance evaluation of Decision Making Units under uncertainty
No full textThe paper presents a novel cross-efficiency fuzzy Data Envelopment Analysis (DEA) technique for evaluating different elements (Decision Making Units or DMUs) under uncertainty. In order to evaluate the performance of several DMUs while dealing with uncertain input and output data, the presented technique employs triangular fuzzy numbers. A fuzzy triangular efficiency is associated to each DMU through a cross evaluation obtained by a compromise between suitably chosen objectives. Results are then defuzzified to provide a ranking of the DMUs. The proposed method is applied to the performance evaluation of healthcare systems in a region of Southern Italy. The DMU data uncertainty derives from ongoing reforms and the reported assessment is conducted firstly in order to evaluate and rank the efficiency of the considered healthcare systems, and subsequently to assess the evolution of the performance of one of the most affected among these DMUs by the reform plans. The case study demonstrates the model ease of application, its discriminative power among DMUs when compared to a more classical fuzzy DEA approach, and the usefulness in planning and validating targeted reforms in the case of healthcare systems
Efficient Resource Planning of Intermodal Terminals under Uncertainty
No full textThis paper presents a decision support tool for the efficient resource planning and management of intermodal terminals under uncertainty, allowing to address the planning issue under imprecise or uncertain data (e.g., estimates on flows, resource utilization, operating conditions). The procedure consists of three steps: 1) the definition of a Timed Petri Net model of the terminal; 2) the computation of suitable performance indices to evaluate whether the current configuration is able to cope with a foreseen increase in the freight flows; 3) in the case of not satisfactory values of the indices at the previous step, the simulation of alternative planning solutions and the detection of the most efficient one via a cross efficiency fuzzy Data Envelopment Analysis technique. In order to test its effectiveness, the procedure is applied to a real case study. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved
A fuzzy technique for supply chain network design with quantity discounts
No full textThis paper proposes a hierarchical technique for Supply Chain Network (SCN) efficiency maximisation under uncertainty composed of three steps. The first step extends a previous fuzzy cross-efficiency Data Envelopment Analysis approach, originally intended for suppliers’ selection, in order to evaluate and rank all the actors in each SCN stage under conflicting nondeterministic criteria. Afterwards, a fuzzy linear integer programming model is stated and solved for each pair of subsequent SCN stages to determine the quantities required from each stakeholder to maximise the overall SCN efficiency while satisfying the estimated demand and respecting the nodes capacity. Finally, a heuristics is applied to limit the exchange of small quantities in the SCN, in which the trade is not economically convenient according to quantity discounts. An illustrative example from the literature shows the technique effectiveness
Multi-Criteria Decision Making techniques for the management of public procurement tenders: A case study
No full textMulti-Criteria Decision Making (MCDM) techniques are mathematical tools that help decision makers evaluating and ranking in an automatic way many possible alternatives over multiple conflicting criteria in highly complex situations. Several MCDM approaches exist, and their application fields are numerous, including the Supplier Selection Problem (SSP), which is an important problem in the management field. The aim of this paper is to perform a comparative analysis among some selected well-known MCDM techniques to show how they can properly support the specific decision making process of Public Procurement (PP) tenders, which is a particular type of the SSP, characterized by very stringent rules, thus requiring a specific assessment. Indeed, PP is a field characterized by the need for transparency, objectivity, and non-discrimination, which requires tendering organizations to explicitly state the adopted awarding method, the chosen decision criteria, and their relative importance in the call for proposals. However, this field has been seldomly investigated in the pertinent literature and thus the aim of this paper is to overcome such a limitation. In particular, this work focuses on the most commonly adopted methods in the field of supplier selection, namely the Analytic Hierarchy Process (AHP), the Preference Ranking Organization METHod for Enrichment of Evaluations (PROMETHEE), the Multi Attribute Utility Theory (MAUT), and the Data Envelopment Analysis (DEA). First, we adapt these techniques to the PP problem and its requirements. Then, by means of some real tenders at a European Institution, the selected techniques are compared with each other and with the currently adopted methodology in their classical deterministic setting, to identify which method best suits the specific requirements of PP tenders. Hence, since nowadays uncertainty is inherent in data from real applications, and can be modelled by expert evaluations through fuzzy logic, the comparison is extended to the fuzzy counterparts of two of the most promising selected approaches, i.e., the Fuzzy AHP and the Fuzzy DEA, showing that these methods can be effectively applied to the PP sector also in the presence of uncertainty on the tenders data
An integrated approach for warehouse analysis and optimization: A case study
No full textThe paper focuses on the analysis and optimization of production warehouses, proposing a novel approach to reduce inefficiencies which employs three lean manufacturing tools in an integrated and iterative framework. The proposed approach integrates the Unified Modeling Language (UML) - providing a detailed description of the warehouse logistics - the Value Stream Mapping (VSM) tool - identifying non-value adding activities - and a mathematical formulation of the so-called Genba Shikumi philosophy - ranking such system anomalies and assessing how they affect the warehouse. The subsequent reapplication of the VSM produces a complete picture of the reengineered warehouse, and using the UML tool allows describing in detail the updated system. By applying the presented methodology to the warehouse of an Italian interior design producer, we show that it represents a useful tool to systematically and dynamically improve the warehouse management. Indeed, the application of the approach to the company leads to an innovative proposal for the warehouse analysis and optimization: a warehouse management system that leads to increased profitability and quality as well as to reduced errors
A Technique for Supply Chain Network Design under Uncertainty using Cross-Efficiency Fuzzy Data Envelopment Analysis
No full textThe paper focuses on Supply Chain Network Design (SCND) under uncertainty. We propose a SCND method extending an approach originally proposed by some of the authors for supplier ranking. The novel method integrates the cross-efficiency Data Envelopment Analysis (DEA) and fuzzy set theory to manage the SCND problem considering nondeterministic input and output data. After ranking all the actors belonging to each SCN stage, a linear integer programming model is stated and solved for each pair of subsequent SC stages to maximize the overall SCN efficiency, while respecting the available capacity at each node and satisfying customers' demand. A case study is presented to show the technique effectiveness
A train load planning optimization model for intermodal freight transport terminals: A case study
No full textDespite the emerging positive trend of rail freight transport, especially in intermodal contexts, the optimization of intermodal terminals is addressed only by few studies and mainly for seaport terminals. This paper fills this gap presenting a train load1 planning optimization model for intermodal rail-road terminals. The proposed model maximizes the train commercial value while respecting priority, physical, financial, and prosecution constraints (i.e., taking into account containers that prosecute to a subsequent terminal after the train destination). The presented method has been successfully tested on a real case study - The rail-road terminal of an Italian intermodal logistics company that is a leader in the European market - showing its effectiveness and ease of application. © 2013 IEEE
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