A Constructivist Grounded Theory Study of Airfield Lighting Maintenance Management Strategy

Asset management programs can keep senior airport managers informed of the performance and life-cycle costs of assets critical to airport operations. With this information, managers can adjust operations and maintenance to minimize costs without sacrificing service quality. However, program implementation is costly and time-consuming. In addition to management and information technology changes, the individual maintenance shops must also develop and incorporate new data collection processes into their everyday workflow. Knowledgeable and experienced maintenance managers must evaluate the data, consider alternatives, and find strategies to reduce costs without negative impact. Unfortunately, such managers are rare for highly specialized assets like airfield lighting systems and often gain most of their experience working at one airport. This research investigated the maintenance strategies most often used for airfield lighting, examined which criteria affected strategy choices, and asked how managers make their selections. The researcher interviewed 23 participants from 15 airports, including facility managers, maintenance engineers, and supervisors. Interview statements were first individually coded in detail and then grouped using focused codes to enable the continuous comparison of each organization’s approach to addressing common problems. Ultimately, the analysis identified eight primary criteria that managers should consider when selecting a maintenance strategy. The process used by U.S. commercial service airports for selecting a maintenance management strategy is modeled as a Multi-Criteria Decision-Making (MCDM) problem. The model includes a problem goal, the criteria affecting the decision, and all the possible alternatives. MCDM models can employ various quantitative decision support systems such as Simple Additive Weighting (SAW), which requires subject matter experts to assign weights to the performance of the multiple alternatives for each of the criteria. However, the research shows that airports consistently use an intuitive decision-making process that relies on the expertise and experience of their maintenance staff. Therefore, this research constructed a theory of airfield lighting maintenance strategy selection modeled as an MCDM problem using an intuitive decision support system. Maintenance managers should consider each of the following criteria when considering their work strategy: access, environment, regulations, budget, design, condition, impetus, and staff. Data analysis also found nine alternative maintenance strategies divided into corrective and preventive types. Corrective maintenance involves action after an asset degradation or failure has occurred. Preventive maintenance is the action taken before problems to prevent degradation and failure. Research shows that maintenance managers consider corrective maintenance to be less costly. However, overuse of corrective maintenance results in higher risks of unexpected asset failure and higher costs over the long-term. In comparison, preventive maintenance may require more daily effort but yields more reliable system performance and lower asset life-cycle costs. In practice, successful maintenance requires using both strategies. Asset management practices require maintenance managers to measure and analyze their system performance, then regularly consider how they might change the maintenance program to minimize operating and maintenance costs without sacrificing performance. This research provides information helpful to maintenance managers with their strategy selection. Future research should investigate developing a quantitative decision-support system that maintenance managers could integrate into the current process and potentially deploy to maintenance organizations wanting supplemental guidance

Portuguese airports and their hinterland: a geographical efficiency analysis using analytic network process combined with data envelopment analysis

Os aeroportos e o seu hinterland encontram-se hoje em dia sob o foco de intensa investigação académica em termos de impactos económicos, sociais e ecológicos. Neste trabalho, visamos o estudo da eficiência geográfica dos aeroportos portugueses, usando para o efeito três Análises Envoltórias de Dados (DEA) com Rendimentos Variáveis à Escala (VRS), e uma ponderação das eficiências técnicas obtidas através do VRS DEA. Estes modelos são previamente apoiados por uma selecção de inputs e outputs com base nas prioridades definidas através do Processo Analítico de Rede (ANP). Observa-se que os aeroportos de Lisboa (continental) e de Santa Maria (ilha) se encontram na fronteira eficiente para todos os outputs seleccionados (com rendimentos constantes à escala). Sete aeroportos das ilhas obtêm resultados de eficiência técnica bastante bons, com especial destaque para Santa Maria, Corvo, Graciosa e Horta. O aeroporto de Faro obtém níveis de eficiência técnica especialmente baixos para os outputs número de destinos directos e volume de carga processada. Conclui-se que os aeroportos, ao contrário do que seria expectável, não sofrem de uma dissociação da eficiência consoante a sua localização geográfica, tipo de operação (Carga ou Passageiros) ou tamanho efectivo do aeroporto. Os aeroportos com uma função Low Cost apresentam resultados aquém dos obtidos para os aeroportos com operações ditas mais generalistas, por via do efeito do número de destinos

Creative trans-border cooperation in the field of operations research and sustainable development in civil engineering

The paper presents an overview of the history and achievements of trans-border cooperation in the Lithuania-Germany-Poland triangle in planning instruments in Construction Management, decision-making theory, application of Operational Research, and Multiple Criteria Decision Making (MCDM) methods in Civil Engineering and sustainable development. The cooperation and results of the Colloquiums with 35 years of tradition, their multidimensional nature is underlined. The research instruments, methods, studied phenomena are reviewed and characteristic applications in engineering and economics are presented. The knowledge and combined efforts of three academic centers have created a synergy which set in motion many original methods and spectacular implementations. The Colloquium calendar and the evolution of organizational forms are presented along with the inclusion of the informal EURO Working Group on Operations Research in Sustainable Development and Civil Engineering

12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin

A framework for technology exploration of aviation environmental mitigation strategies

The goal of this thesis was to develop a framework for modeling relevant environmental performance metrics and objectively simulating the future environmental impacts of aviation given the evolution of the fleet, the development of new technologies, and the expansion of airports. By exchanging fidelity for computational speed, a screening-level framework for assessing aviation's environmental impacts can be developed to observe new insights on fleet-level trends and inform environmental mitigation strategies. This was accomplished by developing per class average ``generic-vehicle" models that can reduce the fleet to a few representative aircraft models for predicting fleet results with reasonable accuracy. The method for Generating Emissions and Noise, Evaluating Residuals and using Inverse method for Choosing the best Alternatives (GENERICA) expands a previous generic vehicle formulation to additionally match DNL contours across a subset of airports. Designs of experiments, surrogate models, Monte Carlo simulations, and ``desirability" scores were combined to set the vehicle design parameters and reduce the mean relative error across the subset of airports. Results show these vehicle models more accurately represented contours at busy airports operating a wide variety of aircraft as compared to a traditional representative-in-class approach. Additionally, a rapid method for assessing population exposure counts was developed and incorporated into the noise tool, and the generic vehicles demonstrated accuracy with respect to population exposure counts for the actual fleet in the baseline year. The capabilities of the enabled framework were demonstrated to show fleet-level trends and explore placement of new runways at capacity constrained airports.Ph.D

Sustainable Mobility and Transport

This Special Issue is dedicated to sustainable mobility and transport, with a special focus on technological advancements. Global transport systems are significant sources of air, land, and water emissions. A key motivator for this Special Issue was the diversity and complexity of mitigating transport emissions and industry adaptions towards increasingly stricter regulation. Originally, the Special Issue called for papers devoted to all forms of mobility and transports. The papers published in this Special Issue cover a wide range of topics, aiming to increase understanding of the impacts and effects of mobility and transport in working towards sustainability, where most studies place technological innovations at the heart of the matter. The goal of the Special Issue is to present research that focuses, on the one hand, on the challenges and obstacles on a system-level decision making of clean mobility, and on the other, on indirect effects caused by these changes

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

Incorporating declared capacity uncertainty in optimizing airport slot allocation

Slot allocation is the mechanism used to allocate capacity at congested airports. A number of models have been introduced in the literature aiming to produce airport schedules that optimize the allocation of slot requests to the available airport capacity. A critical parameter affecting the outcome of the slot allocation process is the airport’s declared capacity. Existing airport slot allocation models treat declared capacity as an exogenously defined deterministic parameter. In this presentation we propose a new robust optimization formulation based on the concept of stability radius. The proposed formulation considers endogenously the airport’s declared capacity and expresses it as a function of its throughput. We present results from the application of the proposed approach to a congested airport and we discuss the trade-off between the declared capacity of the airport and the efficiency of the slot allocation process

Symmetric and Asymmetric Data in Solution Models

This book is a Printed Edition of the Special Issue that covers research on symmetric and asymmetric data that occur in real-life problems. We invited authors to submit their theoretical or experimental research to present engineering and economic problem solution models that deal with symmetry or asymmetry of different data types. The Special Issue gained interest in the research community and received many submissions. After rigorous scientific evaluation by editors and reviewers, seventeen papers were accepted and published. The authors proposed different solution models, mainly covering uncertain data in multicriteria decision-making (MCDM) problems as complex tools to balance the symmetry between goals, risks, and constraints to cope with the complicated problems in engineering or management. Therefore, we invite researchers interested in the topics to read the papers provided in the book