Prioritization of aircraft maintenance unit strategies using fuzzy Analytic Network Process: A case study

In this paper, a new methodology for prioritizing strategies using an integrated approach of fuzzy Multiple Criteria Decision Making (MCDM) is proposed. A case study in an aircraft maintenance unit showed that the “Financial” criterion and the sub-criterion of “Competitiveness and Improving Customer Satisfaction” (with weights of 0.3108 and 0.84, respectively) were the most critical ones. Due to the internal relations between the criteria and sub-criteria in the fuzzy MCDM and the opinions of the experts of the aircraft maintenance unit, the weights of the main criteria obtained were closer to the actual conditions.     

Service quality of airports' food and beverage retailers. A fuzzy approach

Nowadays the profitability of airports is largely based on non-aeronautical or commercial activities, and particularly on retail and food and beverage services. Further, researchers concur that shopping, eating and drinking in airports have to be considered an important part of tourists' experience and activities that can significantly enhance or damage the tourist destination image. Despite this, there is still little research that analyses how service quality (SQ) is perceived by passengers consuming food and beverages (F&B) in airport areas. This study aims to deepen the scientific debate on this topic. Specifically, this study applies fuzzy numbers with a sample of 551 passengers flying from Olbia-Costa Smeralda Airport (Sardinia Region, Italy) with the aim of determining how they perceive the SQ delivered by F&B retailers and whether age plays a determinant role in segmentation. Findings reveal which F&B features outperform others; furthermore, they show that age is a moderating factor in consumer satisfaction, with older passengers being less satisfied than their counterparts. This study adds knowledge to the literature devoted to SQ, applying a fuzzy number approach to the under-investigated research area related to F&B consumption in airport areas. Further, it provides information useful to airport managers on the features of F&B services that are most important in shaping consumer satisfaction, based also on their age. Limitations of the study are also discussed and suggestions for future research are given.     

Vehicle routing optimization with soft time windows in a fuzzy random environment

This paper is concerned with a vehicle routing problem with soft time windows (VRPSTW) in a fuzzy random environment. Two objectives are considered: (1) minimize the total travel cost and (2) maximize the average satisfaction level of all customers. After setting up the model for the VRPSTW in a fuzzy random environment, the fuzzy random expected value concept is used to deal with the constraints and its equivalent crisp model is derived. The global–local–neighbor particle swarm optimization with exchangeable particles (GLNPSO-ep) is employed to solve the equivalent crisp model. A case study is also presented to illustrate the effectiveness of the proposed approach.     

A hybrid approach based on fuzzy AHP and 2-tuple fuzzy linguistic method for evaluation in-flight service quality

The in-flight service is one of the most important parts in the whole air travel service process. In order to better understand the passengers' preference and obtain their perception for service quality, the paper proposed a hybrid approach based on fuzzy AHP and 2-tuple fuzzy linguistic method to evaluate in-flight service quality. This study is comprised of three stages. In the first stage, the modified version of SERVQUAL instrument was used and a hierarchy of the evaluation index system for in-flight service quality was constructed. In the second stage we use fuzzy AHP to analyze the structure of the in-flight service evaluation problem. Using linguistic variables, pairwise comparisons for evaluation criteria and sub-criteria are made to determine the weights of criteria and sub-criteria. In the third stage, the ratings of sub-criteria are assessed in linguistic values to express the qualitative evaluation of passengers' subjective opinions, and then the linguistic values are transformed into 2-tuples and the 2-tuple linguistic arithmetic mean operator is utilized to obtain the average ratings of 100 respondents. Using the 2-tuple linguistic weighted average operator to compute the aggregated ratings of criteria and the overall in-flight service quality of alternatives. Finally, we demonstrated the validity and feasibility of the proposed approach by conducting an application study of the comprehensive performance of three airlines' in-flight service quality in China.     

Methodology for assessing dependencies between factors influencing airline pilot performance reliability: A case of taxiing tasks

Pilot performance reliability is critical to civil air transportation safety. Internal and external factors influencing pilot performance reliability are important elements to estimate human error probability. However, dependencies between these factors, including state dependencies and effect dependencies, are always ignored or only partially considered in most human reliability analysis (HRA) method. This paper attempts to develop a methodology incorporating both state and effect dependencies between contributory factors into HRA for airline pilot tasks based on fuzzy logic and the Cognitive Reliability and Error Analysis Method (CREAM). Anchor points were determined for each common performance condition (CPC) state levels through airline pilot elicitation process and then corresponding state and effect fuzzy sets were constructed for each CPC. The CPC dependency fuzzy inference rules were constructed and transformed with reference to the CPC dependency assessing rule in CREAM. And a cognitive failure probability (CFP) calculation method based on the final CPC effect fuzzy sets and the extended CREAM was proposed. To illustrate the use of the proposed methodology, a case study about commercial airline pilot taxiing task was given. The results demonstrate the validity of the proposed methodology and its capability of representing the ambiguity and fuzziness of expert judgement.     

Balanced scorecard based performance measurement of European airlines using a hybrid multicriteria decision making approach under the fuzzy environment

The purpose of this study is to evaluate the performance of the European airlines, using a balanced scorecard perspective. Within this scope, a hybrid multi-criteria approach was used by combining the Fuzzy DEMATEL, Fuzzy ANP, and MOORA methods. The results demonstrate that customer dimensions and profit per customer are the most significant key factors in the balanced scorecard perspective. Additionally, the airline companies with the largest profit (per employee) and highest number of passengers and flights (per employee) had the best scores in the multidimensional performance results. Furthermore, the airline companies with the highest profitability and efficiency are more successful than other companies. Therefore, we recommend European airlines to focus on these aspects in order to improve their performance. This study makes an important contribution to literature by helping to solve a significant problem in the market with the proposed methodology.     

A hybrid fuzzy MCDM approach for mitigating airport congestion: A case in Ninoy Aquino International Airport

In this paper, we introduce the application of an integrated fuzzy multi-criteria decision-making (MCDM) model to mitigate airport congestion which affects the on-time performance of airlines, operational reputation of airports, and air travel experience of passengers. In a classical approach, when congestion occurs at the destination airport while the aircraft is en-route, an air traffic flow management action is prompted for implementation. In selecting the most suitable action in the event of airport congestion, the decision must reflect the multiple criteria nature of the problem as well as the uncertainty and vagueness associated with the decision-making process; thus, an integrated fuzzy MCDM is adopted. The applicability of the proposed approach is demonstrated in a case study at Ninoy Aquino International Airport. It is found that stakeholders of the commercial aviation industry favored to apply rerouting, among other actions, as this satisfies aviation safety as the most prioritized criterion.     

A multi-objective healthcare inventory routing problem; a fuzzy possibilistic approach

This paper presents a new multi-objective mathematical model to address a Healthcare Inventory Routing Problem (HIRP) for medicinal drug distribution to healthcare facilities. The first part of objective function minimizes total inventory and transportation costs, while satisfaction is maximized by minimizing forecast error which caused by product shortage and the amount of expired drugs; Greenhouse Gas (GHG) emissions are also minimized. A demand forecast approach has been integrated into the mathematical model to decrease drug shortage risk. A hybridized possibilistic method is applied to cope with uncertainty and an interactive fuzzy approach is considered to solve an auxiliary crisp multi-objective model and find optimized solutions.     

An empirical investigation of European airline business models: Classification and hybridisation

Airline business models are evolving and what was once a clear distinction between low-cost carriers (LCCs) and full-service carriers (FSCs) is now less apparent. LCCs and FSCs are merging into new hybrid carrier business models, a convergence accomplished in different ways by various airlines. This paper aims to establish how many types of business models exist and to examine the defining characteristics of the various levels of hybridisation. This is an empirical study based on a sample of 49 European airlines. Data are collected in a categorical format, where appropriate, or transformed into categorical variables if numerical. The methodology employed for analysis is the well-established k-modes technique. The clustering process indicates that there are four observable airline categories: FSCs, LCCs, and two hybrid types in between.     

A dynamic network efficiency measurement of airports performance considering sustainable development concept: A fuzzy dynamic network-DEA approach

In this paper, sustainability of airports is considered through a multi-perspective, multi-system, and multi-process operation. It is explored how an extension of fuzzy dynamic network performance measurement approach helps to determine the efficiency performance of an airport system. In this way, a three-pronged approach is intended which considers the internal functions of an airport, functions affecting the community and functions related to the passengers simultaneously. This novel combination makes it possible to have a comprehensive evaluation of airports' performance. Besides, fuzzy extension of SBM dynamic network approach makes it possible to deal better with the vagueness of variables during analysis. So, this extension is valuable from both technical and conceptual aspects which in turn provide useful information and insights for the future design of holistic strategies connected with sustainable development of airports where ever they are.     

Random and fuzzy utility models for road route choice

The objective of this work is the specification, calibration and validation of a route choice model distinguishing the phases of set perception and route choice among the alternatives belonging to the chosen set. Route generation is performed with a selective multi-criteria approach; route choice is performed using random and fuzzy utility models. As regards the fuzzy utility models, a new specification of a fuzzy model is introduced. Random and fuzzy utility models are compared and applied on a test road network and were specified and calibrated for national road freight transport on a real Italy-wide network.     

Planning and optimization of intermodal hub-and-spoke network under mixed uncertainty

This paper addresses the planning and optimization of intermodal hub-and-spoke (IH&S) network considering mixed uncertainties in both transportation cost and travel time. Different from previous studies, this paper develops a novel modeling framework for the IH&S network design problem to jointly minimize the expected value of total transportation costs and the maximum travel time requirement in term of critical value. A new hybrid methodology by combining fuzzy random simulation (FRS) technique and multi-start simulated annealing (MSA) algorithm is designed to solve the proposed model. Numerical experiments are implemented to verify the effectiveness of the proposed model and solution approach.     

End-of-life aircraft treatment in the context of sustainable development,lean management,and global business

Dealing with retired aircraft taking into account the environmental, social, and economic impacts is emerging as an air transportation problem for the near future. The players involved in the problem wish to solve this challenge in a systematic way to benefit from the value extracted from the core activities of the end-of-life (EoL) aircraft treatment, decrease the environmental impacts, and at the same time maximize the social value. This paper proposes a holistic approach to EoL aircraft treatment considering lean management, sustainable development, and the global business environment. An integrated optimization framework is proposed to support decision-making at both the strategic and managerial levels. The flexibility of the framework makes it possible to compare different business models, dismantling strategies, and network structures that impact the efficiency, stability, and leanness of the recovery network. A solution methodology based on the joint application of fuzzy interactive approach and genetic algorithm is introduced. The application perspective and guidelines for pilot study are also provided. To the best of our knowledge, this is the first time that recovery of EoL aircraft is considered based on three aspects of sustainability, lean, and global business. Therefore, this study provides many promising perspectives in this context to enrich the literature of EoL aircraft as a new aviation industry challenge and opportunity.     

A new digital service quality model and its strategic analysis in aviation industry using interval-valued intuitionistic fuzzy AHP

Today, airline companies have to provide digital products and services to ensure customer satisfaction. Accordingly, classical service quality models are not sufficient to capture customer expectations, and new digital service quality (DSQ) models should emerge. This study aims to propose a new and genuine DSQ model. The proposed model consists of digital tangibles, reliability, digital interaction, digital trust, and customer-centricity dimensions; and 35 criteria related to them. Importance degrees of criteria are determined with the IVIF AHP method. The validity of the proposed model is verified, employing a real case concerning the Turkish airline industry. The results show that the most significant dimension is digital trust, and the three most important criteria are proactive customer service, cybersecurity, and customer insight.     

A fuzzy assessment method to airport waste management: A case study of Congonhas Airport,Brazil

This study presents a fuzzy mathematical model to support and evaluate airport waste management. The model generates a waste management index, composed of three dimensions, and it was applied in a case study of Congonhas Airport, located in Brazil. In addition to the mathematical model, the nonparametric Mann-Kendall test was applied to verify the existence of bias in the obtained results. The results showed that there is a concern on the part of the airport regarding waste management, reflected in the Fuzzy Waste Management Index (FWMI) results. They also indicated that there was an improvement in waste management in 2015 compared to 2014, resulting from increased accounting for recyclables and awareness of the airport community. The developed model proved to be an important tool to support the decision making of airport managers, including aspects related to waste management steps, and there may be adjustments that may be made to include new indicators.     

Establishment and application of fuzzy decision rules: an empirical case of the air passenger market in Taiwan

This paper develops a framework for creating fuzzy decision rules by socio‐economic variables, transactional record variables and customer benefit variables. Fuzzy decision rules may be applied on marketing systems of businesses. This research uses fuzzy k‐means algorithm and C4.5 decision tree algorithm to generate fuzzy decision rules. The framework is applied on the air passenger market of Taiwan for an empirical case study. Results of this research found two non‐fuzzy (crisp) decision rules and two fuzzy decision rules, which can be applied on the customer relationship management systems of airlines. Copyright © 2010 John Wiley & Sons, Ltd.     

A methodology based on the Analytic Hierarchy Process for the quantitative assessment of emergency preparedness and response in road tunnels

The paper presents and discusses a methodology to judge the effectiveness of the preparedness activities in case of accidents in road tunnels by considering the system from several points of view (i.e. structural/technical, organizational/human, and contextual). Due to the different nature of the criteria involved in the assessment activity, we chose to apply the Analytic Hierarchy Process methodology (Saaty, T.L. (2006). Fundamentals of Decision Making and Priority Theory with the Analytic Hierarchy Process, RWS Publications, Pittsburgh) that allows comparing and appraising quantitatively variables that are incommensurable and that may originate from distinct and separate areas. The paper identifies the hierarchic structure necessary to measure both the performance of the emergency response system for road tunnel accidents and the weights for assessing their relative importance. Finally, the methodology is applied to a case study on a transnational road tunnel between Italy and France to show a feasible evaluation of the sensitivity of the structure to the input variables in order to find the most valuable enhancing and improving actions.     

客运站营销工作质量的层次综合评价方法

铁路客运站营销工作受多方面因素影响,且大多数因素具有模糊性难以定量化。为此,以定性定量相结合的系统思想为指导,运用层次分析与模糊综合评价的相关方法,对客运站的营销工作质量进行综合评价。在介绍方法原理与步骤的基础上,应用层次模糊评价法对某客运站的营销工作质量进行了评价。     

A conceptual evaluation framework for organisational safety culture: An empirical study of Taipei Songshan Airport

This study included three phases. The first phase was to establish an evaluation hierarchy framework for organisational safety culture in accordance with the fuzzy Delphi method (FDM) and including expert perspectives. The second phase involved evaluating weight and rankings in order of importance using a fuzzy analytic hierarchy process. In the third phase, analysis of variance (ANOVA) and the Scheffe multiple comparison test were used to compare the different evaluation constructs and criteria of the airport's various internal safety management units. The study results demonstrated that Taipei Songshan Airport's general management units believed that ‘Safety Supervision’, ‘Safety-oriented Working Environment’ and ‘System of Incentives and Penalties’ should be considered implementation priorities to improve overall performance in the airport organisational safety culture. In addition, the ANOVA results revealed significant differences among the airport's management units with respect not only to the personal dimension, including ‘Safety Values’, ‘Safety Evaluation Standards’ and ‘Safety Management Updates’, but also to the situational dimension, such as ‘Safety Communication and Commitment’ and ‘Injury Rate’.     

An emergency logistics distribution approach for quick response to urgent relief demand in disasters

Quick response to the urgent relief needs right after natural disasters through efficient emergency logistics distribution is vital to the alleviation of disaster impact in the affected areas, which remains challenging in the field of logistics and related study areas. This paper presents a hybrid fuzzy clustering-optimization approach to the operation of emergency logistics co-distribution responding to the urgent relief demands in the crucial rescue period. Based on a proposed three-layer emergency logistics co-distribution conceptual framework, the proposed methodology involves two recursive mechanisms: (1) disaster-affected area grouping, and (2) relief co-distribution. Numerical studies with a real large-scale earthquake disaster occurring in Taiwan are conducted, and the corresponding results indicate the applicability of the proposed method and its potential advantages. We hope that this study can not only make the proposed emergency logistics system available with more benefits to the development of emergency logistics systems for the urgent needs of disaster areas around the world but also stimulate more excellent researches concerning emergency logistics management.