Defuzzification of groups of fuzzy numbers using data envelopment analysis

Defuzzification is a critical process in the implementation of fuzzy systems that converts fuzzy numbers to crisp representations. Few researchers have focused on cases where the crisp outputs must satisfy a set of relationships dictated in the original crisp data. This phenomenon indicates that these crisp outputs are mathematically dependent on one another. Furthermore, these fuzzy numbers may exist as a group of fuzzy numbers. Therefore, the primary aim of this thesis is to develop a method to defuzzify groups of fuzzy numbers based on Charnes, Cooper, and Rhodes (CCR)-Data Envelopment Analysis (DEA) model by modifying the Center of Gravity (COG) method as the objective function. The constraints represent the relationships and some additional restrictions on the allowable crisp outputs with their dependency property. This leads to the creation of crisp values with preserved relationships and/or properties as in the original crisp data. Comparing with Linear Programming (LP) based model, the proposed CCR-DEA model is more efficient, and also able to defuzzify non-linear fuzzy numbers with accurate solutions. Moreover, the crisp outputs obtained by the proposed method are the nearest points to the fuzzy numbers in case of crisp independent outputs, and best nearest points to the fuzzy numbers in case of dependent crisp outputs. As a conclusion, the proposed CCR-DEA defuzzification method can create either dependent crisp outputs with preserved relationship or independent crisp outputs without any relationship. Besides, the proposed method is a general method to defuzzify groups or individuals fuzzy numbers under the assumption of convexity with linear and non-linear membership functions or relationships

Integrated Production-Inventory Models in Steel Mills Operating in a Fuzzy Environment

Despite the paramount importance of the steel rolling industry and its vital contributions to a nation’s economic growth and pace of development, production planning in this industry has not received as much attention as opposed to other industries. The work presented in this thesis tackles the master production scheduling (MPS) problem encountered frequently in steel rolling mills producing reinforced steel bars of different grades and dimensions. At first, the production planning problem is dealt with under static demand conditions and is formulated as a mixed integer bilinear program (MIBLP) where the objective of this deterministic model is to provide insights into the combined effect of several interrelated factors such as batch production, scrap rate, complex setup time structure, overtime, backlogging and product substitution, on the planning decisions. Typically, MIBLPs are not readily solvable using off-the-shelf optimization packages necessitating the development of specifically tailored solution algorithms that can efficiently handle this class of models. The classical linearization approaches are first discussed and employed to the model at hand, and then a hybrid linearization-Benders decomposition technique is developed in order to separate the complicating variables from the non-complicating ones. As a third alternative, a modified Branch-and-Bound (B&B) algorithm is proposed where the branching, bounding and fathoming criteria differ from those of classical B&B algorithms previously established in the literature. Numerical experiments have shown that the proposed B&B algorithm outperforms the other two approaches for larger problem instances with savings in computational time amounting to 48%. The second part of this thesis extends the previous analysis to allow for the incorporation of internal as well as external sources of uncertainty associated with end customers’ demand and production capacity in the planning decisions. In such situations, the implementation of the model on a rolling horizon basis is a common business practice but it requires the repetitive solution of the model at the beginning of each time period. As such, viable approximations that result in a tractable number of binary and/or integer variables and generate only exact schedules are developed. Computational experiments suggest that a fair compromise between the quality of the solutions and substantial computational time savings is achieved via the employment of these approximate models. The dynamic nature of the operating environment can also be captured using the concept of fuzzy set theory (FST). The use of FST allows for the incorporation of the decision maker’s subjective judgment in the context of mathematical models through flexible mathematical programming (FMP) approach and possibilistic programming (PP) approach. In this work, both of these approaches are combined where the volatility in demand is reflected by a flexible constraint expressed by a fuzzy set having a triangular membership function, and the production capacity is expressed as a triangular fuzzy number. Numerical analysis illustrates the economical benefits obtained from using the fuzzy approach as compared to its deterministic counterpart

Optimization Models Using Fuzzy Sets and Possibility Theory

Optimization is of central concern to a number of disciplines. Operations Research and Decision Theory are often considered to be identical with optimization. But also in other areas such as engineering design, regional policy, logistics and many others, the search for optimal solutions is one of the prime goals. The methods and models which have been used over the last decades in these areas have primarily been "hard" or "crisp", i.e. the solutions were considered to be either feasible or unfeasible, either above a certain aspiration level or below. This dichotomous structure of methods very often forced the modeler to approximate real problem situations of the more-or-less type by yes-or-no-type models, the solutions of which might turn out not to be the solutions to the real problems. This is particularly true if the problem under consideration includes vaguely defined relationships, human evaluations, uncertainty due to inconsistent or incomplete evidence, if natural language has to be modeled or if state variables can only be described approximately. Until recently, everything which was not known with certainty, i.e. which was not known to be either true or false or which was not known to either happen with certainty or to be impossible to occur, was modeled by means of probabilities. This holds in particular for uncertainties concerning the occurrence of events. probability theory was used irrespective of whether its axioms (such as, for instance, the law of large numbers) were satisfied or not, or whether the "events" could really be described unequivocally and crisply. In the meantime one has become aware of the fact that uncertainties concerning the occurrence as well as concerning the description of events ought to be modeled in a much more differentiated way. New concepts and theories have been developed to do this: the theory of evidence, possibility theory, the theory of fuzzy sets have been advanced to a stage of remarkable maturity and have already been applied successfully in numerous cases and in many areas. Unluckily, the progress in these areas has been so fast in the last years that it has not been documented in a way which makes these results easily accessible and understandable for newcomers to these areas: text-books have not been able to keep up with the speed of new developments; edited volumes have been published which are very useful for specialists in these areas, but which are of very little use to nonspecialists because they assume too much of a background in fuzzy set theory. To a certain degree the same is true for the existing professional journals in the area of fuzzy set theory. Altogether this volume is a very important and appreciable contribution to the literature on fuzzy set theory

Untangling hotel industry’s inefficiency: An SFA approach applied to a renowned Portuguese hotel chain

The present paper explores the technical efficiency of four hotels from Teixeira Duarte Group - a renowned Portuguese hotel chain. An efficiency ranking is established from these four hotel units located in Portugal using Stochastic Frontier Analysis. This methodology allows to discriminate between measurement error and systematic inefficiencies in the estimation process enabling to investigate the main inefficiency causes. Several suggestions concerning efficiency improvement are undertaken for each hotel studied.info:eu-repo/semantics/publishedVersio

An integrated approach to value chain analysis of end of life aircraft treatment

Dans cette thèse, on propose une approche holistique pour l’analyse, la modélisation et l’optimisation des performances de la chaîne de valeur pour le traitement des avions en fin de vie (FdV). Les recherches réalisées ont débouché sur onze importantes contributions. Dans la première contribution, on traite du contexte, de la complexité, de la diversité et des défis du recyclage d’avions en FdV. La seconde contribution traite du problème de la prédiction du nombre de retraits d’avions et propose une approche intégrée pour l’estimation de ce nombre de retraits. Le troisième et le quatrième articles visent à identifier les parties prenantes, les valeurs perçues par chaque partenaire et indiquent comment cette valeur peut affecter les décisions au stade de la conception. Les considérations relatives à la conception et à la fabrication ont donné lieu à quatre contributions importantes. La cinquième contribution traite des défis et opportunités pouvant résulter de l’application des concepts de la chaîne logistique verte, pour les manufacturiers d’avions. Dans la sixième contribution, un outil d’aide à la décision a été développé pour choisir la stratégie verte qui optimise les performances globales de de toute la chaîne de valeur en tenant compte des priorités et contraintes de chaque partenaire. Dans la septième contribution, un modèle mathématique est proposé pour analyser le choix stratégique des manufacturiers en réponse aux directives en matière de FdV de produits comme le résultat des interactions des compétiteurs dans le marché. La huitième contribution porte sur les travaux réalisés dans le cadre d’un stage chez le constructeur d’avions, Bombardier. Cette dernière traite de l’apport de « l’analyse du cycle de vie » au stade de la conception d’avions. La neuvième contribution introduit une méthodologie d’analyse de la chaîne de valeur dans un contexte de développement durable. Finalement, les dixième et onzième contributions proposent une approche holistique pour le traitement des avions en FdV en intégrant les concepts du « lean », du développement durable et des contraintes et opportunités inhérentes à la mondialisation des affaires. Un modèle d’optimisation intégrant les modèles d’affaires, les stratégies de désassemblage et les structures du réseau qui influencent l’efficacité, la stabilité et l’agilité du réseau de récupération est proposé. Les données requises pour exploiter le modèle sont indiquées dans l’article. Mots-clés: Fin de vie des avions, analyse de la chaîne de valeurs, développement durable, intervenants.The number of aircrafts at the end of life (EOL) is continuously increasing. Dealing with retired aircrafts considering the environmental, social and economic impacts is becoming an emerging problem in the aviation industry in near future. This thesis seeks to develop a holistic approach in order to analyze the value chain of EOL aircraft treatment in the context of sustainable development. The performed researches have led to eleven main contributions. In the first contribution, the complexity and diversity of the EOL aircraft recycling including the challenges and problem context are discussed. The second contribution addresses the challenges for estimation of retired aircrafts and proposes an integrated approach for prediction of EOL aircrafts. The third and fourth contributions aim to identify the players involved in EOL recycling context, values perceived by different shareholders and formulate that how such value can affect design decisions. Design stage consideration and manufacture’s issues are discussed and have led to four main contributions. The fifth contribution addresses the opportunities and challenges of applying green supply chain for aircraft manufacturers. In the sixth contribution, a decision tool is developed to aid manufactures in early stage of design for their green strategy choices. In the seventh contribution, a mathematical model is developed in order to analyze the strategic choice of manufacturers in response to EOL directives as the result of the interaction of competitors in the market. An internship project has been also performed in Bombardier and led to the eighth contribution, which addresses life cycle approach and incorporating the sustainability in early stage of design of aircraft. The ninth contribution introduces a methodology for analyzing the value chain in the context of sustainable development. Finally, the tenth and eleventh contributions propose a holistic approach to EOL aircraft treatment considering lean principals, sustainable development, and global business environment. An optimization model is developed to support decision making in both strategic and managerial level. The analytical approaches, decision tools and step by step guidelines proposed in this thesis will aid decision makers to identify appropriate strategies for the EOL aircraft treatment in the sustainable development context. Keywords: End of life aircraft, value chain analysis, sustainable development, stakeholders

Proceedings of the Second Joint Technology Workshop on Neural Networks and Fuzzy Logic, volume 2

Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by NASA and the University of Texas, Houston. Topics addressed included adaptive systems, learning algorithms, network architectures, vision, robotics, neurobiological connections, speech recognition and synthesis, fuzzy set theory and application, control and dynamics processing, space applications, fuzzy logic and neural network computers, approximate reasoning, and multiobject decision making

\u3ci\u3eThe Conference Proceedings of the 1998 Air Transport Research Group (ATRG) of the WCTR Society, Volume 3 \u3c/i\u3e

UNOAI Report 98-8https://digitalcommons.unomaha.edu/facultybooks/1151/thumbnail.jp

The Conference Proceedings of the 1998 Air Transport Research Group (ATRG) of the WCTR Society

Thirteen papers (presentations) from the 8th World Conference on Transportation Research are presented. Topics include European Airline competition, cost analyses, performance evaluations, deregulation; aviation policy in Southeast Asia; corporate involvement in European business transportation; and cycles in the airline industry

Prospects for Research in Transport and Logistics on a Regional: Global Perspective (I: February 2009: İstanbul: Turkey)

"International Conference on Prospects for Research in Transport and Logistics on a Global - Regional Perspective" has undertaken the challenge to host very important experts and practitioners of Transport and Logistics from a large spectrum of countries. In our opinion, the conference has fulfilled the purpose of establishing an International Society; "Eurasian and Eastern Mediterranean Institute of Transportation and Logistics Association (EMIT)" that is expected to have a very promising role in the Eurasian and Eastern Mediterranean countries. The purpose of the Association is to contribute to establishing and developing the exchange of research work between all parts of the world in all fields of transportation and logistics. This proceedings book consists of 13 chapters, grouping the contributed papers into the following categories: Global Issues in Logistics and Transportation (3 papers), Regional Issues in Logistics and Transportation (2 papers), Education and Training in Logistics and Transportation (2 papers), Supply Chain Management (3 papers), Sustainable Transport Policies, Traffic Engineering (4 papers), Evaluation of Public Policies, Network Models and Environment (4 papers), Contemporary Topics in Transport and Logistics (7 papers), Transport Planning and Economics (3 papers), Planning, Operations, Management and Control of Transport and Logistics (3 papers), Transport Modeling (5 papers), Freight Transportation and Logistics Management (7 papers), Transport and Land Use (3 papers), Transport Infrastructure and Investment Appraisal (2 papers) It can be readily seen from this volume of selected papers that all papers do elaborate on rather timely problems in the fields of expertise related to Transport and Logistics, which have a considerable global importance.TÜBİTAK; Doğuş Üniversitesi ; Uluslararası Nakliyeciler Derneği ; İDO ; Tırsan ; Türk Hava YollarıCommittees, i -- Words of Welcome and Gratitude, ii -- Introduction, iii -- Chapter 1 Global Issues in Logistics and Transportation, 1 -- Potential to Reduce GHG through Efficient Logistic Concepts, 3 -- Werner Rothengatter -- A methodological framework for the evaluation and prioritisation of multinational transport projects: the Case of euro-asian transport linkages, 21 / Dimitrios TSAMBOULAS, Angeliki KOPSACHEILI -- Container port throughput performance - case study: Far east, north west european and mediterranean ports, 29 / Vesna DRAGOVIC-RADINOVIC, Branislav DRAGOVIC, Maja SKURIC, EmirĞIKMIROVlC and Ivan KRAPOVIC -- Chapter 2 Regional Issues in Logistics and Transportation, 35 -- Logistics service providers in turkey: A panel data analysis, 37 / Emel AKTAŞ, Füsun ÜLENGİN, Berrin AĞARAN, Şule ÖNSEL -- Milestones in the process of survey preparation for the logistics sector: case study for Istanbul, Turkey, 43 / Evren POSACI, Darçın AKIN -- Chapter 3 Education and Training in Logistics and Transportation, 51 -- Education in transport and logistics in an age of global economy, 53 / Yücel Candemlr -- The role of education and training in the supply chain sector, 59 / David Maunder -- Chapter 4 Supply Chain Management, 64 -- Modeling reverse flows in a closed -loop supply chain network, 67 / Vildan ÖZKIR, Önder ÖNDEMİR and Hüseyin BAŞLIGİL -- Strategic analysis of green supply chain management practices in T urkish automotive industry, 73 / Gülçin BÜYÜKÖZKAN and Alişan ÇAPAN -- A new framework for port competitiveness: the network approach, 79 / Marcella DE MARTINO, Alfonso MORVILLO -- Chapter 5 Sustainable Transport Policies, Traffic Engineering, 87 -- Clean transport: innovative solutions to the creation of a more sustainable urban transport system, 89 / Ela BABALIK-SUTCLIFFE -- Effects of urban bottlenecks on highway traffic congestion: case study of Istanbul, Turkey, 95 / Darçın AKIN and Mehtap ÇELİK -- Establishing an effective training module for IMDG code in MET institutions, 105 / Kadir CICEK, Metin CELIK -- An investment decision aid proposal towards choice of container terminal operating systems based on information axioms, 109 / Metin CELIK, Selcuk CEBI -- Chapter 6 Evaluation of Public Policies, Network Models and Environment, 115 -- Possibilistic linear programming approach for strategic resource planning, 117 / Özgür KABAK, Füsun ÜLENGİN -- A structural equation model for measuring service quality in passenger transportation, 125 / G.Nilay YÜCENUR and Nihan ÇETİN DEMİREL -- Analysis of potential gain from using hybrid vehicles in public transportation, 133 / İrem DÜZDAR and Özay ÖZAYDIN -- Optimization of e-waste management in Marmara region - Turkey, 141 / İlke BEREKETLİ, Müjde EROL GENEVOIS -- Chapter 7 Contemporary Topics in Transport and Logistics, 147 -- Future prospects on urban logistic research, 149 / Rosârio MACÂRIO, Vasco REIS -- An analyze of relationship between container ships and ports development, 155 / Branislav DRAGOVIC, Vesna Dragovic-Radinovic, Dusanka Jovovic, Romeo Mestrovic and Emir Ğikmirovic -- A holistic framework for performance measurement in logistics management, 161 / Yasemin Claire ERENSAL -- Heuristics for a generalization of tsp in the context of PCB assembly, 167 / Ali Fuat ALKAYA and Ekrem DUMAN -- Premium e-grocery: Exploring value in logistics integrated service solutions, 173 / Burçin BOZKAYA, Ronan De KERVENOAEL and D. Selcen Ö. AYKAÇ -- T ravelers response to VMS in the Athens area, 179 / Athena TSIRIMPA and Amalia POLYDOROPOULOU -- Regional airports and local development: the challenging balance between sustainability and economic growth, 189 / Rosârio MACÂRIO and Jorge SILVA -- Chapter 8 Transport Planning and Economics, 195 -- How financial constraints and non-optimal pricing affect the design of public transport services, 197 / Sergio R. Jara-Diaz and Antonio Gschwender -- Revenue management for returned products in reverse logistics, 203 / Mesut KUMRU -- Intra-city bus planning using computer simulation, 211 / Reza AZIMI and Amin ALVANCHI -- Chapter 9 Planning, Operations, Management and Control of Transport and Logistics, 217 -- A review of timetabling and resource allocation models for light-rail transportation systems, 219 / Selmin D. ÖNCÜL, D. Selcen Ö. AYKAÇ, Demet BAYRAKTAR and Dilay ÇELEBİ -- An approach of integrated logistics HMMS model under environment constraints and an application of time scale, 225 / Fahriye Uysal, Ömür Tosun, Orhan Kuruüzüm -- Freight transport planning with genetic algorithm based projected demand, 231 / Soner HALDENBILEN, Ozgur BASKAN, Huseyin CEYLAN and Halim CEYLAN -- Chapter 10 Transport Modeling, 239 -- Inverse model to estimate o-d matrix from link traffic counts using ant colony optimization, 241 / Halim CEYLAN, Soner HALDENBILEN, Huseyin CEYLAN, Ozgur BASKAN -- The impact of logistics on modelling commercial freight traffic, 251 / Ute IDDINK and Uwe CLAUSEN -- A comparative reviewof simulation-based behavior modeling for travel demand generation, 257 / Seda Yanık, Mehmet Tanyaş -- An efficiency analysis of turkish container ports using the analytic network process, 269 / Senay OĞUZTİMUR, Umut Rıfat TUZKAYA -- A multi-objective approach to designing a multicommudity supply chain distribution network with multiple capacities, 277 / Gholam Reza Nasiri, Hamid Davoudpour and B.Karimi -- Chapter 11 Freight Transportation and Logistics Management, 283 -- Evaluation of turkey’s freight transportation, 285 / Burcu KULELİ PAKand BaharSENNAROĞLU -- Short sea shipping, intermodality and parameters influencing pricing policies in the Mediterranean region: The Italian context, 291 / Monica GROSSO, Ana-Rita LYNCE, Anne SILLA, Georgios K. VAGGELAS -- Relevant strategic criteria when choosing a container port - the case of the port of Genoa, 299 / Monica Grosso, Feliciana Monteiro -- Determination of optimum fleet size and composition - A case study of retailer in Thailand, 307 / Terdsak RONGVIRIYAPANICH and Kawee SRIMUANG -- New container port development: forecasting future container throughput, 313 / Dimitrios TSAMBOULAS, Panayota MORAITI -- Sea port hinterland flows and opening hours: the way forward to make them match better 319 / Marjan BEELEN, Hilde MEERSMAN, Evy ONGHENA, Eddy VAN DE VOORDE and Thierry VANELSLANDER -- International road freight transport in Germany and the Netherlands driver costs analysis and French perspectives, 327 / Laurent GUIHERY -- Chapter 12 Transport and Land Use, 335 -- Land rent and new transport infrastructure: How to manage this relationship?, 337 / Elena SCOPEL -- Effects of pavement characteristics on the traffic noise levels, 345 / Aybike ONGEL and John HARVEY -- Fuzzy medical waste disposal facility location problem, 351 / Yeşim KOP, Müjde EROL GENEVOIS and H. Ziya ULUKAN -- Chapter 13 T ransport Infrastructure and Investment Appraisal, 357 -- Agents’ behavior in financing Italian transport infrastructures, 359 / Paolo BERIA -- Free trade agreements in the mediterranean region: a box-cox analysis, 367 / Matthew KARLAFTIS, Konstantinos KEPAPTSOGLOU and Dimitrios TSAMBOULA

Assembly Line

An assembly line is a manufacturing process in which parts are added to a product in a sequential manner using optimally planned logistics to create a finished product in the fastest possible way. It is a flow-oriented production system where the productive units performing the operations, referred to as stations, are aligned in a serial manner. The present edited book is a collection of 12 chapters written by experts and well-known professionals of the field. The volume is organized in three parts according to the last research works in assembly line subject. The first part of the book is devoted to the assembly line balancing problem. It includes chapters dealing with different problems of ALBP. In the second part of the book some optimization problems in assembly line structure are considered. In many situations there are several contradictory goals that have to be satisfied simultaneously. The third part of the book deals with testing problems in assembly line. This section gives an overview on new trends, techniques and methodologies for testing the quality of a product at the end of the assembling line