Integrated schedule planning with supply-demand interactions for a new generation of aircrafts

We present a model where we integrate schedule design, fleet assignment and demand models to maximize the profit of an airline. The objective of the study is to identify the challenges behind the integration of demand modeling into the optimization model and develop methodologies to overcome these challenges. The study is in the context of a collaborative work between EPFL and EPFL Middle East. A new air transportation concept, Clip-Air, is developed at EPFL which is a modular innovative aircraft with detachable load units that increase the flexibility. The decoupling of the load (capsules) and carrying units (wings) is believed to improve the airline operations. Clip-Air, being a flexible transportation concept, brings more interest into the integration of supply and demand models. Therefore models are adapted to the Clip-Air case and comparative analysis is done between standard aircrafts and Clip-Air to quantify the potential advantages. Considered supply model is an integrated schedule design and fleet assignment model. Integrated demand model is specified as a logit model where utility of the itineraries are explained by fare, departure time and number of stops which are shown to have explanatory power in the literature. Fare class segmentation is considered in the optimization model as different fare classes have different sensitivities suggested by the demand model. Furthermore we include supply and recapture effects in order to better represent the demand where recapture ratios are based on a logit model similar to the demand model. The resulting model is a mixed integer nonlinear problem and as a first step to deal with the high complexity of the problem, we present a heuristic method based on Lagrangian relaxation and sub-gradient optimization

Airline Fleet Assignment and Schedule Planning

Airline fleet assignment plays important role for efficient operation of airlines. In order to save costs from the procurement and maintenance of extra aircrafts, the airline operators would always seek to minimise the fleet size, while at the same time being able to operate all the flights without shortage of aircraft. Therefore, the daily flight schedule of the airline must be prepared in such a way that the destinations can be served with minimum number of aircrafts. Considering this, there is huge prospect of using optimisation techniques to select the optimum mix of various types of aircrafts in the airline fleet and thereby to produce an optimum flight schedule

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

Modeling Aerospace Ground Equipment (AGE) Usage in Military Environments

There is a wide array of multi-attribute decision analysis methods and associated sensitivity analysis procedures in the literature. However, there is no detailed discussion of sensitivity analysis methods solely relating to additive hierarchical value models. The currently available methodology in the literature is unsophisticated and can be hard to implement into complex models. The methodology proposed in this research builds mathematical foundations for a robust sensitivity analysis approach and extends the current methodology to a more powerful form. The new methodology is easy to implement into complex hierarchical value models and gives flexible and dynamic capabilities to decision makers during sensitivity analysis. The mathematical notation is provided in this study along with applied examples to demonstrate this methodology. Global and local sensitivity analysis are considered and implemented using the proposed robust technique. This research provides consistency and a common standard for the decision analysis community for sensitivity analysis of multi-attribute deterministic hierarchical value models

Agent-based modelling of air transport demand

Constraints such as opening hours or passenger capacities influence travel options that can be offered by an airport and by the connecting airlines. If infrastructure, policy or technological measures modify transport options, then the benefits do not only depend on the technology, but also on possibly heterogeneous user preferences such as desired arrival times or on the availability of alternative travel modes. This paper proposes an agent-based, iterative assignment procedure to model European air traffic and German passenger demand on a microscopic level, capturing individual passenger preferences. Air transport technology is simulated microscopically, i.e. each aircraft is represented as single unit with attached attributes such as departure time, flight duration or seat availability. Trip-chaining and delay propagation can be added. Microsimulation is used to verify and assess passengers’ choices of travel alternatives, where those choices improve over iterations until an agent-based stochastic user equilibrium is reached. This requires fast simulation models, thus, similar to other approaches in air traffic modelling a queue model is used. In contrast to those approaches, the queue model in this work is solved algorithmically. Overall, the approach is suited to analyze, forecast and evaluate the consequences of mid-distance transport measures

Enhancing competitive advantage through successful lean realisation within the Aviation Maintenance Repair and Overhaul (MRO) industry

Purpose: Lean is increasingly being applied within the aviation Maintenance and Repair (MRO) Industry to mitigate industry challenges. This Lean application is premised on its success within other industrial contexts particularly the automotive industry. Furthermore, many organisations within automotive industry have attributed their enhanced competitive positioning to the Lean application. Indeed, Toyota (a pioneer of Lean) present Lean as a key proponent to its global success. However, with literature suggesting that there cannot be a direct transference of Lean from one industry to another and with the MRO having distinct characteristics different from the automotive industry, this research seeks to present how competitive advantage can be achieved through successful Lean realisation. Design/Methodology/Approach: The status of MRO Lean engagements presented is first presented based on the syntheses of literature review and empirical study (facilitate by an industry-wide survey). The means through which the MRO realises its value proposition is established and the structural assessment of the MRO industry as it pertains to competitiveness is also defined. The role of Lean in enhancing the value delivery system to enhance competitive positioning is operationalised through a case study. Findings: Using Porter’s forces of competition, this research establishes the competitive MRO landscape revealing the distinct characteristics of the MRO industry and how Lean can be accurately appropriated to enhance competitive advantage. The MRO Value Delivery System (VDS) is also delineated providing the complete system within which Lean is to be deployed (as opposed to the prevalent limited application of Lean in operational context alone). The case exemplar successfully validates and operationalises the approach to Lean application within MRO to enhance competitive advantage. Research Limitations: A case study example was used for this research, and whilst the outcomes were consistent with the research proposal, it still requires wider validation. Practical and Social Implications: This research demystifies and helps MRO organisations in assessing their Lean engagements but also in provide a roadmap and informs their strategy in improving their competitive status through Lean realisation

Connecting air freight services with the road transport network, Case: FREJA Transport & Logistics Oy

This master’s thesis is made as a commission for FREJA Transport & Logistics Oy. Aim of the thesis is to research how the current export air freight process can be improved with DMAIC cycle. Export air freight process needed improvement because process was mostly outsourced and company’s own resources used poorly. Research is limited to consider only export air transports from Finland to outside Europe. Theoretical part of the research was divided to two separate sections. First section handled the concept of business process improvement, which included such issues as Six Sigma, DMAIC cycle, and SCOR metrics. Second section of the theoretical part considered air freight. Air freight was discussed through six themes: demand for air cargo, aircrafts, transport units, air cargo operators, air freight costs, and future in the market. Lastly a common export air freight process was comprised and explained to set basis for the empirical part. In the empirical part, process was improved step by step as per the DMAIC cycle to reveal the issues causing the limited use of own resources. Main reason for variation and inefficient use of resources was outsourcing and by that linking number of intermediaries in the process. The solution was to insource the road transportation from the consignor to the gateway airport. Results revealed that operating costs can be reduced with the improved process and still offer evenly competitive service. Results of the empirical part were validated by process charts, profitability calculations and other supporting documentation created during the DMAIC cycle.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Future Transportation

Greenhouse gas (GHG) emissions associated with transportation activities account for approximately 20 percent of all carbon dioxide (co2) emissions globally, making the transportation sector a major contributor to the current global warming. This book focuses on the latest advances in technologies aiming at the sustainable future transportation of people and goods. A reduction in burning fossil fuel and technological transitions are the main approaches toward sustainable future transportation. Particular attention is given to automobile technological transitions, bike sharing systems, supply chain digitalization, and transport performance monitoring and optimization, among others