A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. University of the Witwatersrand, Johannesburg, 2016 / Given a flight schedule with fixed departure times and cost, solving the fleet assignment problem assists airlines to find the minimum cost or maximum revenue assignment of aircraft types to flights. The result is that each flight is covered exactly once by an aircraft and the assignment can be flown using the available number of aircraft of each fleet type. This research proposes a novel, non-linear integer programming fleet assignment model which differs from the linear time-space multi-commodity network fleet assignment model which is commonly used in industry. The performance of the proposed model with respect to the amount of time it takes to create a flight schedule is measured. Similarly, the performance of the time-space multicommodity fleet assignment model is also measured. The objective function from both mathematical models is then compared and results reported. Due to the non-linearity of the proposed model, a genetic algorithm (GA) is used to find a solution. The time taken by the GA is slow. The objective function value, however, is the same as that obtained using the time-space multi-commodity network flow model. The proposed mathematical model has advantages in that the solution is easier to interpret. It also simultaneously solves fleet assignment as well as individual aircraft routing. The result may therefore aid in integrating more airline planning decisions such as maintenance routing. / MT2017

No description available.

Thesis (PhD)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: For more than a decade there has been an economic need to mitigate the negative effects of the air transport industry's innate sensitivity to cyclical developments as well as the effects of its inherent lack of substantial profits. The past 20 years were additionally marked by a change in policy that prompted various countries to liberalise and privatise their civil passenger air transportation industry. At the same time, airlines' business ambitions became more global, tapping into markets beyond countries' or continents' main gateways. All three aspects started to change the pattern of airline competition and required new business models. Key features of airlines' novel business models are geographic expansion and thus market development. Global expansion strategies and market development activities in passenger air transportation are, however, not easily and fluidly executable. The airline industry is, to some extent, still nationally regulated, thus impeding passenger airlines from fully participating in the global market-scene and from freely entering promising geographies. Concomitantly, the competitive landscape in which scheduled passenger airlines operate changed drastically, with travel value chains occasionally undergoing revolutionary transformations on both the supply and the demand side. Finally, the air transport service reveals several peculiarities that impact its production, distribution and consummation. These characteristics have inspired the execution of novel forms of competitive strategies that are described and critically discussed in this dissertation. Within this context, a main root cause for passenger airline partnerships appears to be its continued regulation and the circumvention thereof through the horizontal joining of forces, thus emulating concentration tendencies that have long been a fixture in other globalising industries. Consequently, horizontal interairline partnerships were induced and identified as a key competitive device with which to weather the challenges of the new air transport rivalry structures, the increasingly deregulated environment, and the impediments of sustained market regulation. All major airlines are now involved in some type of horizontal collaboration. The spectrum of these linkages is wide and ranges from loose, unattached, operative agreements to long-term, far-reaching, strategic ones, the most salient forms and instruments of which are thoroughly scrutinised in this dissertation. This dissertation additionally presents the general core inducing economic drivers of carrier interrelationship, which are cost reduction, revenue generation and corporate power considerations. While these aspects offer a multitude of possible partnership forms and instruments, the bulk of airline linkages, however, is presently constituted of joint revenue generation and, consequently, jointly pursued marketing and market expansion goals. In view of these causes, the present dissertation engages in a profound discussion of the rationales behind interairline partnerships, their likely evolution and effects on management practice. Essentially, the key importance of airline partnerships in meeting basic economic imperatives on the one hand, while circumventing persistent regulation on the other, questions the sustainability of incumbent carriers' current business models. There are clear indications that a structured sequence of events in establishing interairline linkages is a key success factor for horizontal airline partnerships. However, the empirical examination of contemporary partnerships' governance structures and managerial practice strongly points to a lack of ample tools with which to establish airline partnerships, select the appropriate match between alliance goals and intensity, and govern alliances during their entire life-cycles. This drawback seems particularly unacceptable in view of the urgent requirement for more appropriate managerial practice in today's discontinuous air transport business environment, and speaks loudly of the need for a framework with which to enhance airline partnership output. Most ideally, a coherent, structured sequence of events should be followed in partnership formation, organisational set-up and management in order to bring an alliance to fruition. On this basis, the establishment of a collaboration governance organisation, adequately mirroring the specific partnership type and meeting the specific demands of all partners involved, is equally identified and described as a fundamental success driver in this dissertation. Further structural, organisational and functional issues thereafter need to be considered in order to transform the joint business venture of two horizontally allied carriers into a venture for mutual success. The most essential of these are introduced in this dissertation. Synergy plays a central role in this context. Synergy, as the overreaching intention and result of working together towards a common goal, must be anchored as a prime objective of all forms of partnership activities. Synergy through interfirm linkages can be derived from various collaborative areas and is greatly influenced by both internal and external factors. One gauge for synergy, in particular for the transformation of synergy potentials into synergy effects, is partnership intensity. The measurement of partnership intensity can be used to perpetually monitor the benefits of partnership activities. At the same time, inconsistent or uneven partnership intensity can indicate the existence of dissynergies or frailties in the alliance. The underlying theories of collaborative synergy generation, its main drivers and impediments, with particular reference to horizontal partnerships of scheduled passenger airlines, are explored in this dissertation. In recognition of the theoretical and practical background of airline partnerships and the acknowledged problems associated with their establishment and operation, the present dissertation proposes a novel model dynamically supporting the quest for synergy in airline interrelationships. Incorporating the goals of synergy generation and its continual measurement in interairline partnerships, the synergy audit is designed as a dynamic managerial tool. The synergy audit functions as a recurring device for unleashing all the positive partnership benefits of collaborative scope and width. It aids airline alliance management in transforming the desired benefits of partnership activities - synergy potentials - into real, tangible synergy effects during the entire partnership life cycle. The tool A.PIE (Airline Partnership Intensity Evaluator) supports the synergy audit and, which idiosyncratic to the airline industry, multidimensionally applies the deduced relationship of partnership intensity and synergy to the most salient partnership areas and functions. The present dissertation shapes understanding of the true drivers and complexities of today's airline partnerships. It proposes a circular, multidimensional and dynamic model, thus attempting to enhance the set-up, performance and output of horizontal airline collaboration. From this point of view it endeavours to fill the gap identified in contemporary airline partnership management and practice. / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

The deregulation of the airline industry created a myriad of changes in the U.S. air transport system that has both defended and sparked debate on the wisdom of such policy change for over three decades. One of the promises of deregulation from its proponents in the 1970s was increased competition that would lead to a reduction in fares for consumers. Historic data and literature has indeed shown this to be to the case as average airfares have trended downward especially over the last twenty years. Nonetheless, the industry has become much more complex since deregulation in terms of pricing to the point that very sophisticated yield management computer models are used to achieve an optimum balance between load factors and price. Consequently, this has in turn translated into a haphazard experience for most air travelers in the United States; for instance, the cost of a ticket is sometimes lower traveling from coast to coast than within a particular region of the U.S. and paid fares for the exact same trip can deviate dramatically, often based on variation in the date of purchase. Additionally, this has also resulted in a spatial pattern where certain regions throughout the country have enjoyed lower airfares more so than others. This research seeks to identify this regional disparity using a geographically weighted regression and spatial autoregressive models in a sample of 6,200 routes between 80 primary U.S. airports. The results from the global model showed that variables which measure competition (airlines), operating cost (flights, distance) and elasticity (layover time) proved to be statistically significant and had a positive relationship with airfare The GWR results indicated that while some factors like distance, and hub size, were statistically significant almost nationwide, other factors such as frequency, presence of low cost carriers, and numbers of airlines were only statistically significant at certain airports. Finally, the spatial regressions models indicate that the spatial autocorrelation found in U.S. airfares resemble the first order properties of spatial autocorrelation (i.e. spatial heterogeneity) and not the second order properties (i.e. spatial dependence). / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

机票超售,即售出的機票多於飛機客艙座位的數量，已經作為“國際慣例“被航空公司廣泛採用。但是这种做法是有争议的，因為其容易導致航班超售，使得旅客被拒登機而滯留，影響航空公司的聲譽。在這篇論文中，我們使用逆向拍賣的機制尋找自願放棄登機資格的旅客以收回部份已預售的低端機票來滿足高端旅客的需求，并同時根據拍賣實現的結果來賠償被拒絶登機旅客。具體地說，我們建立一個二期的機票銷售模型，並且假定低端與高端旅客分別在第一第二個銷售期到來，而航空公司通過決定其在兩個銷售期的銷售策略，使得其利潤最大化。在模型中，航空公司可利用逆向拍賣的方法，要求低端旅客在購買機票的時候，提交一個其在因為航班超售時，自願放棄座位的赔偿要求。當航班超售時，航空公司可根據低端旅客的競投信息，從中挑選出價最低的旅客，通過滿足他們的賠償要求，收回他們的機票以滿足高端旅客的需求。我们发现我们的机制在大多数情况下，可以提高航空公司的利润，改善航班的登機效率，同时，也能滿足部份低端旅客通過改變計劃行程獲取賠償的需求。我們也會比較逆向拍賣機制與其他現有機制，例如固定價格補償機制。此外，我們也會就逆向拍賣機票銷售模型中的定價问题进行研究。 / With increasing applications of revenue management, airline companies often oversell their tickets. This practice is controversial because some passengers would not be able to board when the number of show-up customers exceeds the available seats. And this might make the affected customers upset and thus affect the future revenue of the airline. In this paper, we propose a new mechanism - a call-back auction, in which the passengers are asked to submit a bid to indicate the compensation they would like to receive for giving up their seats and changing their original flight schedule. This could provide the airline with information to select passengers with the lowest compensation requirements and also reduce the negative impact on customer relationship. We develop a model with booking limit decision and examine the impact of this call-back auction mechanism on the airline's profitability and compare it with other existing mechanisms such as fixed-price compensation. We find that our mechanism can lead to higher profit for the airlines in most cases. In this study, pricing issues are also examined. / Detailed summary in vernacular field only. / Zhong, Zhiheng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 72-76). / Abstracts also in Chinese. / Table of Contents --- p.vii / Chapter 0 --- Notation / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Literature Review --- p.7 / Chapter 3 --- Call-back Auction --- p.13 / Chapter 3.1 --- The Concept --- p.13 / Chapter 3.2 --- Implementation --- p.14 / Chapter 4 --- A Two-Period Model with Call-back Auction --- p.19 / Chapter 4.1 --- Uniform Price Call-back Auction --- p.21 / Chapter 4.2 --- Numerical Examples --- p.27 / Chapter 4.3 --- First-price Call-back Auction --- p.35 / Chapter 4.4 --- Revenue Comparison --- p.39 / Chapter 4.5 --- Call-back Auction with Reserve Compensation --- p.41 / Chapter 4.6 --- Alternative Information Structure --- p.50 / Chapter 5 --- Endogenous High-fare Price --- p.59 / Chapter 5.1 --- Additive Demand Function --- p.60 / Chapter 6 --- Conclusion --- p.68 / Bibliography --- p.72

Thesis (Ph.D)--Industrial and Systems Engineering, Georgia Institute of Technology, 2009. / Committee Co-Chair: George L. Nemhauser; Committee Co-Chair: Martin W. P. Savelsbergh; Committee Member: Bruce K. Sawhill; Committee Member: Joel Sokol; Committee Member: Ozlem Ergun. Part of the SMARTech Electronic Thesis and Dissertation Collection.

The thesis begins by examining the evolution of human performance modeling from the initial stimulus-response methods introduced during the industrial revolution to model factory worker productivity, continues with a discussion of the information processing model where human cognition was modeled as a series of actions carried out in a predefined order, and ends with the concept of cognitive control whereby cognition is not considered a context-free mental process but modeled as an individual's ability to maintain control under varying contexts and to counter the effects of disturbances. The results from a preliminary evaluation conducted to determine if CCMs could be measured and if they provided any additional insight cognitive work are presented, and reveal that CCMs could be measured and the self-assessed CCM varied as predicted. A design process is developed which utilizes the CCMs as representing specific patterns of activity, thus specifying the design requirements. Following this design process, a prototype is created and evaluated using a controlled experiment to examine the effectiveness of the CWSS. The experiment examines performance, workload, and patterns of activity, and has several interesting findings. The first is that performance was independent of the almost all of the predictors and covariates including participant's Self-assessed CCM, with the exception of CCM transitions. As in the preliminary study, participants who reported transitioning between CCMs also reported decreased performance, increased frustration and actually performed worse. Second, perceived performance varied linearly with a participant's self-assessed CCM, but not with the actual performance. Third, participants report lower levels of effort when using a CWSS DM that matched their operational CCM. Finally, the design process successfully created a CWSS with DMs which support strategic and tactical CCMs. Unfortunately, no specific performance improvements were found for cases where the participant's CCM matched the DM as hypothesized, calling into question the effectiveness of creating different design modes for performance improvement. This thesis presents two methods for measuring CCMs: one direct single scale and one indirect composite scale. The measurements correlate highly. Both have a high degree of face validity and user acceptance. In the end, the composite measure may be a more robust measure of CCM because it provides a greater degree of diagnosticity by specifically inquiring after different aspects of CCM and is less susceptible to an individual's interpretation of the relative importance of the multiple dimensions of CCMs included in the definitions.

Study project (MEcon) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This assignment explains the search for a mechanism that can increase tourism flow by improved utilisation of airline capacity. The inherent characteristics of air transport indicate that the industry is subject to low short term marginal costs and that it is very tempting to award discount tariffs for last minute bookings. The challenge to management is to attract new passengers with discount tariffs without loosing full tariff passengers. Travel clubs are one of the mechanisms that are utilised to achieve aforementioned objective. These clubs offer mainly discount tariffs on hotel accommodation, car hire and airline tickets to their members. The acceptability of a travel club that applies restricting measures such as for example short notice periods, adaptable depart and return dates and shortened lead times have been tested in the South African market. The majority of respondents surveyed were in favour of such a travel club. An important finding is that South Africans are prepared to travel in a chosen month but that the travel dates within that month are adaptable in exchange for discount tariffs. The research also indicate that the availability of funds was decisive in the decision to travel or not to travel over seas. In order to overcome this problem the introduction of a providence account is recommended as part of the travel club's products. The challenge for the travel club is thus to consolidate the demand and to match it with the excess airline capacity. / AFRIKAANSE OPSOMMING: Hierdie werkstuk beskryf die soeke na 'n meganisme wat toerismevloei kan verhoog deur die verbeterde kapasiteitsbenutting van lugvervoer. Die inherente kenmerke van lugvervoer toon dat die bedryf onderhewig is aan lae korttermyn marginale koste en dat die versoeking groot is om afslagtariewe vir op die nippertjie besprekings toe te staan. Die uitdaging vir die bestuur is om nuwe passasiers met afslagtariewe te lok sonder om voltariefpassasiers prys te gee. Reisklubs is een van die meganismes wat gebruik word om die voorgenoemde doelwit te bereik. Hierdie klubs bied hoofsaaklik afslagtariewe op hotelverblyf, motorhuur en vliegtuigkaartjies aan hul lede. Die aanvaarbaarheid van 'n reisklub wat beperkende rnaatreels soos, byvoorbeeld, kort kennisgewingstydperke, aanpasbare vertrek en terugkeer datums en verkorte leityd toepas, is in die Suid-Afrikaanse mark getoets. Die meerderheid van respondente in die ondersoek was ten gunste van so 'n reisklub. 'n 8elangrike bevinding is dat Suid-Afrikaners bereid is om in 'n gekose maand te reis, maar dat die spesifieke reisdatums in daardie maand aanpasbaar is in ruil vir afslagtariewe. Die navorsing toon ook dat die beskikbaarheid van fondse deurslaggewend is in die besluit om oorsee te reis of nie. Om hierdie probleem te oorkom word die instelling van 'n voorsieningsrekening aanbeveel as dee I van die reisklub se produkte. Die uitdaging aan die reisklub is dus om die vraag te konsolideer en dan af te stem op die oormaatkapasiteit van die lugrederye.

This thesis addresses two planning problems motivated by the operations of PSOD air transportation: scheduled maintenance planning, and base location and fleet allocation. In the first part of the thesis, we study tactical planning for scheduled maintenance which determines the daily maintenance capacities for two operating conditions: a growth phase and the steady state. We model tactical maintenance capacity planning during the growth phase as an integer program and develop an optimization-based local search to solve the problem. Tactical planning of steady state maintenance capacity concerns a special case for which we determine the optimal and the long run capacities with a pseudo-polynomial time algorithm. In the second part of the thesis, we address operational planning for scheduled maintenance which is concerned with assigning itineraries to jets and determining the specific jets to be scheduled for maintenance on a daily basis given a certain maintenance capacity. We present a solution methodology that employs a look-ahead approach to consider the impact of our current decisions on the future and decomposes the problem exploiting the differences between jets with respect to the proximity to their next maintenance. We further develop an integrated framework in order to capture the interaction between operational level maintenance decisions and flight scheduling. In the third and final part of the thesis, we present the tactical level base location and fleet allocation problem. As PSOD air transportation experiences changes in travel demand and fleet size, decisions regarding where to open new bases and how to allocate the number of jets among the bases are made. We first present a solution approach in which high level information about flight scheduling is used in a traditional facility location problem. We next develop a model that works directly with transportation requests and integrates a simplified version of flight scheduling with the base location and fleet allocation decisions in order to capture more detail.

Doctorat en sciences sociales, politiques et économiques / info:eu-repo/semantics/nonPublished