Havayollarında uçuş aksaklıkları problemi için bir çözüm yaklaşımı ve uygulaması

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Son yıllarda havacılık sektöründe artan rekabet ile birlikte hava yolu şirketleri operasyonlarını daha az kayıp hedefleyen daha dinç şekilde yönetmeye yönelmişlerdir. Havayolu operasyonları karmaşıklığının yanı sıra tam zamanında gerçekleştirilme gerekliliği olan ve her hangi bir bozulma durumunda zincirleme etkisi daha fazla unsuru ilgilendiren operasyonlardır. Uçuş çizelgelerini geliştiren ekipler günlük operasyonlarda meydana gelebilecek aksaklıkları genelde hesaba katmazlar. Ancak mekanik arızalar, kötü hava koşulları, yer problemleri, hava trafik kısıtları gibi durumlar çizelgelerin yeniden iyileştirilmesini gerektirebilir. Bu yüzden şirketlere çok ağır maliyetler getirilebilen bu konu üzerinde son yıllarda daha fazla durulmaktadır. Uçuş aksaklıkları yönetiminin en zor tarafı aylar, haftalar boyunca geliştirilen planların dakikalarla ifade edilebilecek bir süre içerisinde yeniden değerlendirilmesini zorunluluğudur. Bununla beraber etkin bir aksaklık yönetimi, maliyet azaltma ve müşteri iyi niyetini kaybetmeme konusunda önemli avantajlar sağlamaktadır. Daha önce yapılan çalışmalarda uçuş aksaklıkları probleminin çözümünde simülasyon, etmen tabanlı yaklaşımlar, kısıt programlama ve benzeri bir çok teknik kullanılmıştır. Bu çalışmada söz konusu problemin çözümü için bir bilgi tabanlı karar destek sistemi önerilerek bu yaklaşım doğrultusunda bir yazılım geliştirilmiştir. Geliştirilen yazılım uzman deneyimi ve düzenlemelere dayalı bilgi tabanları, model tabanı ve mevcut sistemin veri tabanlarını içermektedir. Aksaklık durumlarına göre uygulanabilecek senaryolar ve ayrıntılı maliyetleri ile birlikte aksaklık sonucu orijinal tarifeye dönüş süresi raporlanmıştır.With the inceasing competition in recent years, airline companies tend to manage their operations aiming fewer loss in a robust manner. Airline operations are complex operations and have the neccessity of being performed just in time and more knockon relevant elements in the event of a disruption. Flight schedule developers generally don’t take into account flight disruptions that may occur in dailiy operations. But, becouse of the mechanical disorders, bad weather conditions, aircraft on ground problems and airport/ air traffic limitations airline companies may have to recover all their schedules. Therefore, this subject causing heavy costs for airline companies is studied more frequently in recent years. The most difficult part of this problem is, the obligation of recovering all schedules developed through months, in a few minutes. Nevertheless an efficient disruption management policy helps to reduce costs and gaining customer goodwill. Simulation, agent based approaches, constraint programming and similar techniques are used in previous studies on flight disruptions problem. In this thesis study a knowledge based decision support system is suggested and a software is developed. The developed software includes knowledge bases which are based on expert experience and government regulations, model bases and data bases. Applicable scenarios and detailed costs according to disruption types and the time for returning the original schedule is reported

Robust Aircraft Routing and Flight Retiming

In this paper, we propose an integrated model for the robust aircraft routing and flight retiming problem. The model optimizes a slack-based robustness measure that explicitly takes heed of passengers in connection and aircraft as well. We provide empirical evidence of the relevance of the proposed approach using computational experiments that were carried out on real-data, provided by Amadeus, SAS.ou

Optimierung des Flugzeugeinsatzes nach Brennstoffeffizienz

Die Arbeit widmet sich der Einsatzplanung von Luftfahrzeugen (LFZ) und fokussiert dabei auf die herausfordernde Thematik des Verschleißes, der zu einer Heterogenität in der Brennstoffeffizienz innerhalb der Flotte führt. Dieser heterogene Effekt wird durch den sogenannten 'Performance Factor' (PF) quantifiziert, der den Verbrauch im Vergleich zu einem nicht verschleißbehafteten Referenz-LFZ adjustiert. Trotz der nachgewiesenen Auswirkungen auf die Effizienz wird der PF bisher in der Einsatzplanung weitgehend vernachlässigt. Das Ziel dieser Forschungsarbeit besteht in der systematischen Untersuchung des Potenzials zur Reduzierung des Brennstoffbedarfs und der damit verbundenen CO2-Emissionen durch eine effizienzorientierte Einsatzplanung mittels Berücksichtigung des PF. Zu diesem Zweck wird ein taktisches Modell, das sogenannte 'TARP-Modell,' entwickelt. Es ermöglicht eine integrierte Lösung der Phasen des Aircraft Routings und des Tail Assignments, wodurch individuelle Flugdurchführungskosten unter Berücksichtigung der Heterogenität der Flüge und der PF-Verteilung in der Flotte ermittelt werden können. Die erzielten Ergebnisse verdeutlichen, dass eine effizienzorientierte Einsatzplanung eine Senkung der Brennstoffkosten um etwa 0,25% bis 0,5% ermöglicht. Selbst bei unvorhergesehenen Flugplanstörungen und der vermehrten Nutzung von sogenannten Aircraft Swaps (TARP-R-Modell) bleibt das Potenzial weitestgehend erhalten, sofern der PF angemessen in die Entscheidungsfindung integriert wird. Es ist jedoch zu beachten, dass das Potenzial mit zunehmender Komplexität in der Flug- und LFZ-Zuordnung durch verstärkte Restriktionen abnehmen kann. Die vorliegende Arbeit leistet somit einen Beitrag zur Ressourcenschonung und zur Verringerung der Klimawirksamkeit des Luftverkehrs. Es ist anzunehmen, dass zukünftige technologische Fortschritte im Bereich des digitalen Zwillings die Berechnung des PF noch präziser gestalten werden, wodurch dessen Bedeutung sowohl wissenschaftlich als auch operationell weiter an Bedeutung gewinnen dürfte.The thesis is dedicated to the aircraft rotation and assignment and focuses on the challenging issue of aircraft performance degradation, which leads to heterogeneity in fuel efficiency within the fleet. This heterogeneous effect is quantified by the so-called 'Performance Factor' (PF), which adjusts fuel consumption in comparison to a non-worn reference aircraft. Despite its proven impact on efficiency, the PF has largely been disregarded in aircraft planning practices. The main objective of this research is to systematically investigate the potential for reducing fuel consumption and associated CO2 emissions through an efficiency-oriented aircraft planning approach, incorporating consideration of the PF. To achieve this goal, a tactical model, referred to as the 'TARP model,' is developed. The model facilitates an integrated solution to the aircraft routing and tail assignment phases, enabling the determination of individual flight execution costs while accounting for the heterogeneity of flights and PF distribution in the fleet. The results obtained underscore that an efficiency-oriented aircraft planning approach can yield a reduction in fuel costs of approximately 0.25% to 0.5%. Even in the presence of unforeseen flight schedule disruptions and increased utilization of aircraft swaps (TARP-R model), the potential remains largely preserved, provided the PF is adequately integrated into the decision-making process. Nevertheless, it should be noted that the potential may diminish with growing complexity in flight and aircraft assignment, stemming from heightened restrictions. Consequently, this study contributes to resource conservation and the mitigation of the aviation industry's climate impact. Anticipated advancements in digital twin technologies are expected to further refine PF calculations, enhancing its significance both from a scientific and operational standpoint

A PSO approach for robust aircraft routing

To mitigate the impact of unpredictable disruptions, airlines are seeking to proactively design schedules that incorporate some robustness features. In this paper, we propose a novel simulation-optimization approach using a particle swarm optimization algorithm for solving the robust aircraft routing and flight retiming problem. The approach requires inserting buffer times between departure times of flights to improve the robustness of both aircraft and passengers connections. The proposed approach is based on discrete-event simulation for the evaluation of the solutions performance and a Particle Swarm Optimization (PSO) routine for guiding the search towards enhanced solutions. The results of computational experiments that were carried out on a real data are presented.Scopu