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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Comparing airport apron layout designs using computer simulation and the cross-entropy method

Leonard, Trudie 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The demand in air travel is continuously increasing. In order to handle this increase in demand, airports need to physically expand or the management of the airports needs to improve. When the demand at OR Tambo International Airport gets too high, more passengers will need to travel to Lanseria International Airport, which will therefore need to be expanded. The study was done in collaboration with Virtual Consulting Engineers, who decided that the concept of Atlanta International Airport in Georgia, USA, which is ranked the busiest airport in the world, will be used in this expansion. The aim of the study was to minimise passenger walking distances and waiting times at Lanseria International Airport. This was done by comparing di erent airport apron layouts, using simulation, and improving the aircraft gate assignment, using the cross-entropy method. Four di erent designs of airport layouts, all based on that of Atlanta International Airport, were compared in the study. A model of each was developed using simulation. The performance measures used to compare the designs included 1) the average walking distance of arriving and departing passengers at the airport, 2) the average time spent at the airport by arriving and departing passengers, 3) the average distance travelled by aircraft at the airport, 4) the average time by which each aircraft is delayed and 5) the average number of aircraft present at the airport. The walking distance of arriving and departing passengers was largely a ected by the way in which ights were assigned to gates. The gates at the airport are of three di erent sizes: small, medium and large. Small aircraft can park at any of the gates, while medium aircraft can only park at medium or large gates and large aircraft can only park at large gates. Three rules for the ight-to-gate assignment process were developed. In the rst two rules an arriving ight was assigned to the available, suitable gate closest to the terminal building. The constraint that small aircraft cannot be assigned to medium or large gates if there are small gates available and that medium aircraft cannot be assigned to large gates if there are medium gates available, was used in Rule 1 and not in Rule 2. In the third rule, metaheuristic optimisation was used to determine a ight-to-gate assignment schedule with the objective of minimising the passenger walking distances. This metaheuristic optimisation was performed in real-time and was thus repeated every time a delay occurred at the airport. The background of airports, simulation, metaheuristics and relevant case studies were investigated in the literature review. The simulation and metaheuristic optimisation models were then developed. The results identi ed the best of the four designs that were compared. It was also concluded that the use of metaheuristic optimisation, using the cross-entropy method, results in a reduction in passenger walking distances at the airport. / AFRIKAANSE OPSOMMING: Die aantal lugpassasiers neem aanhoudend toe en om in staat te wees om hierdie toename in vraag te hanteer moet lughawens sies uitbrei of die bestuur van die lughawens moet verbeter. Wanneer die vraag by OR Tambo Internasionale Lughawe te hoog raak, gaan meer mense na Lanseria Internasionale Lughawe moet reis. Die lughawe sal dan dus moet uitbrei. Die studie is in samewerking met Virtual Consulting Engineers gedoen. Hulle het besluit dat die konsep van Atlanta Internasionale Lughawe in Georgia in die VSA, wat die besigste lughawe in die w^ereld is, gebruik sal word in die uitbreiding Lanseria Internasionale Lughawe. Die doelwit van die studie was om die loopafstand en die wagtyd van passasiers op Lanseria Internasionale Lughawe te minimeer. Die doelwit is bereik deur verskillende lughawe uitlegte te vergelyk met behulp van simulasie en deur die toekenning van vlugte aan hekke te verbeter, deur gebruik te maak van die "cross-entropy" metode. Die konsep van Atlanta Internasionale Lughawe is gebruik om vier verskillende lughawe uitlegte te ontwerp. Simulasie is gebruik om die vier ontwerpe te vergelyk op grond van 1) die gemiddelde loopafstand van passasiers wat aankom en vertrek, 2) die gemiddelde tyd wat passasiers wat aankom en vertrek spandeer op die lughawe, 3) die gemiddelde afstand wat vliegtuie a ^e op die lughawe, 4) die gemiddelde tyd wat vliegtuie vertraag word, 5) die gemiddelde hoeveelheid vliegtuie teenwoordig op die lughawe. Die loopafstand van passasiers wat aankom en vertrek is grootliks beinvloed deur die manier waarop vliegtuie aan hekke toegeken is. Die hekke op die lughawe is klein, medium of groot. 'n Klein vliegtuig mag by 'n klein, medium of groot hek parkeer, 'n medium vliegtuig mag by 'n medium of groot hek parkeer en 'n groot vliegtuig mag net by 'n groot hek parkeer. Drie reels waarvolgens vliegtuie aan hekke toegeken kan word is ontwikkel. In die eerste twee reels word 'n vliegtuig wat aankom aan die beskikbare hek naaste aan die terminaal gebou toegeken as die hek geskik is vir die vliegtuig. In die eerste reel is die beperking dat klein vliegtuie nie aan medium en groot hekke toegeken mag word as daar klein hekke beskikbaar is nie en dat medium vliegtuie nie aan groot hekke toegeken mag word as daar medium hekke beskikbaar is nie, ingesluit. Hierdie beperking is nie in die tweede reel ingesluit nie. In die derde reel is metaheuristiek optimering gebruik om vliegtuie aan hekke toe te ken. Die doelwit van die metaheuristiek optimering was om die loopafstand van die passasiers te verminder. Elke keer as 'n vliegtuig op die lughawe vertraag was, is die optimering proses is herhaal. Die agtergrond van lughawens, simulasie, metaheuristieke en gevalle studies is bestudeer in die literatuur studie. Daarna is die simulasie en metaheuristiek optimering modelle ontwikkel. Die resultate van die studie het aangedui watter een van die vier lughawe ontwerpe die beste is. Dit is ook beslis dat die gebruik van metaheuristiek optimering, en spesifi ek die "cross-entropy" metode, die loopafstand van passasiers op die lughawe verminder.
12

Impacts of weather on aviation delays at O.R. Tambo International Airport, South Africa

Peck, Lara 11 1900 (has links)
Weather-related delays in the aviation sector will always occur, however, through effective delay management and improved weather forecasting, the impact and duration of delays can be reduced. The research examined the type of weather that caused departure delays, due to adverse weather at the departure station, namely O. R. Tambo International Airport (ORTIA), over the period 2010 to 2013. It was found that the most significant weather that causes such delays are thunderstorms, followed by fog. Other noteworthy elements are rainfall, without the influence of other weather elements, and icing. It was also found that the accuracy of a weather forecast does not impact on the number of departure delays, and thus departure delays due to weather at the departure station are largely unavoidable. However, the length and impact of such delays can be reduced through improved planning. The study highlights that all weather-related delays can be reduced by improved weather forecasts, effective assessment of the weather forecast, and collaborative and timely decision making. A weather impact index system was designed for ORTIA and recommendations for delay reductions are made. / Geography / M. Sc. (Geography)

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