Daily Flight Research Articles

A strategic flight conflict avoidance approach based on a memetic algorithm

Conflict avoidance (CA) plays a crucial role in guaranteeing the airspace safety. The current approaches, mostly focusing on a short-term situation which eliminates conflicts via local adjustment, cannot provide a global solution. Recently, long-term conflict avoidance approaches, which are proposed to provide solutions via strategically planning traffic flow from a global view, have attracted more attentions. With consideration of the situation in China, there are thousands of flights per day and the air route network is large and complex, which makes the long-term problem to be a large-scale combinatorial optimization problem with complex constraints. To minimize the risk of premature convergence being faced by current approaches and obtain higher quality solutions, in this work, we present an effective strategic framework based on a memetic algorithm (MA), which can markedly improve search capability via a combination of population-based global search and local improvements made by individuals. In addition, a specially designed local search operator and an adaptive local search frequency strategy are proposed to improve the solution quality. Furthermore, a fast genetic algorithm (GA) is presented as the global optimization method. Empirical studies using real traffic data of the Chinese air route network and daily flight plans show that our approach outperformed the existing approaches including the GA based approach and the cooperative coevolution based approach as well as some well-known memetic algorithm based approaches.

Influence of seasonal changes in daily activity and annual life cycle of Geotrigona mombuca (Hymenoptera, Apidae) in a Cerrado habitat, São Paulo, Brazil

The foraging activity of Geotrigona mombuca Smith, 1863 was studied under natural conditions aiming to verify the influence of seasonal changes on daily flight activity and annual cycle of the colony. Daily flight activity was monitored for a year based on the observation and counting of foragers leaving and entering the hive, as well as the kind of material transported and meteorological factors such as day time, temperature and relative humidity. The influence of seasonal changes was evidenced by alterations on daily rhythm of flight activity and by differences on transportation of food resources, building material and garbage. These data indicate that forager behavior is related to daily microclimate conditions and it is synchronized with the requirements of colony annual cycle, which determines an intense pollen collection in the summer. Thus, the recomposition of the intranidal population in spring and summer can be ensured, which is characterized both for a higher intensity of flight activity and increase in garbage and resin transport, as well as the swarming process in the spring. In this way, an action targeting the preservation or management of the species in a natural environment should consider that survival and reproduction of the colony depends greatly on the amount of available pollen in late winter.

A Network-Based Model for the Integrated Weekly Aircraft Maintenance Routing and Fleet Assignment Problem

Most studies in airline operations planning research are focused on the optimization problems that deal with a daily flight schedule, which is considered to be the same for every day in the week. While the weekly schedule is more realistic and practical, it increases the complexity of the optimization problems drastically. In this paper, we present a novel weekly rotation-tour network representation for the weekly aircraft maintenance routing problem (WAMRP). Based on this representation, we propose a new network-based mixed-integer linear programming (LP) formulation for the WAMRP; namely, weekly rotation-tour network model (WRTNM). The main advantage of this formulation is that the size of WRTNM only increases linearly with the size of the weekly schedule, and it provides a very tight LP relaxation. In addition, because of the tight LP relaxation, we develop a diving heuristic to solve WRTNM efficiently and effectively. To assess the performance of WRTNM, we tested the WRTNM using eight real-life test cases. The computational results show that the proposed model is very compact and scalable, and is able to find the optimal solutions to the schedule with 5,700 flights and 330 aircraft, approximately the size of the world's largest airlines fleet, within five minutes. We also propose an integrated model to solve the WAMRP with the weekly fleet assignment problem simultaneously. We tested the integrated model on nine self-constructed test cases. The computational results show that the integrated model generates near-optimal solutions to the schedules with 1,700 flights, 8 fleets with 110 aircraft, and approximately a medium-sized airline, in a reasonable time.

Integrated Flight Scheduling and Fleet Assignment Under Airport Congestion

Airport congestion is a major cause for the large delays that currently affect the air transport industry. These delays have huge cost implications—for the U.S. economy these costs were estimated at $32.9 billion in 2007. In this paper, we present a mixed-integer linear optimization model aimed at assisting airlines in the making of integrated flight scheduling and fleet assignment decisions that take aircraft and passenger delay costs explicitly into account. The objective of the model is to maximize the expected profits of an airline that faces a given origin/destination-based travel demand and operates in congested, slot-constrained airports. Both airline competition and airline cooperation are dealt with in the model, though in a simplified manner. The model was applied to a case study involving the main network of TAP Portugal, which comprises 31 airports and 100 daily flight legs. The results obtained through the model suggest that the Portuguese legacy carrier can improve their expected profits significantly, while diminishing the total number of flights and slightly increasing the passengers' average connecting time. The calculation effort involved in the application of the model even on a desktop computer is small enough to allow its real-time utilization in International Air Transport Association scheduling conferences. These findings clearly indicate that the model is a significant addition to the airline planning toolbox.

404 Longitudinal associations between flight schedules and occupational accidents among cabin crew

ObjectivesWork schedules of cabin crew involve early starts, long working hours, night flights and the crossing of time zones. This can impose disturbed sleep, fatigue, lack of alertness, and possibly...

Mixed strategies of griffon vultures' (Gyps fulvus) response to food deprivation lead to a hump-shaped movement pattern.

BackgroundThe need to obtain food is a critical proximate driver of an organism’s movement that shapes the foraging and survival of individual animals. Consequently, the relationship between hunger and foraging has received considerable attention, leading to the common conception that hunger primarily enhances a “food-intake maximization” (FIMax) strategy and intensive search. A complementary explanation, however, suggests a trade-off with precautions taken to reduce the risk of physiological collapse from starvation, under a strategy we denote as “energy-expenditure minimization” (EEMin). The FImax-EEmin trade-off may interact with the forager’s hunger level to shape a complex (non-monotonic) response pattern to increasing hunger. Yet, this important trade-off has rarely been investigated, particularly in free-ranging wild animals.We explored how hunger affects the movements of adult griffon vultures (Gyps fulvus) in southern Israel. Transmitters combining GPS and accelerometers provided high-resolution data on vultures’ movements and behavior, enabling the identification of feeding events and the estimation of food deprivation periods (FDPs, measured in days), which is used as a proxy for hunger.ResultsData from 47 vultures, tracked for 339 ± 36 days, reveal high variability in FDPs. While flight speed, flight straightness and the proportion of active flights were invariant in relation to food deprivation, a clear hump-shaped response was found for daily flight distances, maximal displacements and flight elevation. These movement characteristics increased during the first five days of the FDP sequence and decreased during the following five days. These characteristics also differed between short FDPs of up to four days, and the first four days of longer FDP sequences.These results suggest a switch from FIMax to EEMin strategies along the FDP sequence. They also indicate that vultures’ response to hunger affected the eventual duration of the FDP. During winter (the vultures’ incubation period characterized by unfavorable soaring meteorological conditions), the vultures’ FIMax response was less intensive and resulted in longer starvation periods, while, in summer, more intensive FIMax response to hunger resulted in shorter FDPs.ConclusionsOur results show a flexible, non-monotonic response of free-ranging wild animals to increasing hunger levels, reflecting a trade-off between increasing motivation to find food and the risk of starvation. The proposed trade-off offers a unifying perspective to apparently contradictory or case-specific empirical findings.Electronic supplementary materialThe online version of this article (doi:10.1186/2051-3933-1-5) contains supplementary material, which is available to authorized users.

Differences of the Daily Flight Activity Rhythm in two Neotropical Stingless Bees (Hymenoptera, Apidae)

Stingless bees are mainly tropical and subtropical, eusocial bees and perform activities that are both internal and external to the nest. This study aims to investigate and compare the daily flight activities of Melipona scutellaris Latreille and Frieseomelitta doederleini (Friese). The daily flight activities of the two Meliponini species was regular for both initial and final activities and for preferential time of activity throughout the months, which may indicate the presence of a biological rhythm synchronized by the daily light-dark cycle. Temperature, light intensity and relative humidity probably influenced the rhythms of activity during the day, in a way that may act as a modulator of bee rhythms. M. scutellaris was the larger and darker bees and showed earlier activities and in lower temperatures when compared to F. doederleini, which were smaller bees.

Patterns of Lacewing (Neuroptera: Chrysopidae) Flight Activity, Flight Height and Spatial Distribution of Eggs on Maize Plants

Lacewings (Chrysopidae) are important beneficial insects in nearly all cropping systems. However, monitoring of lacewing numbers is difficult due to the nocturnal behaviour of adults and the difficulty of finding eggs and larvae on plants. Techniques facilitating easy finding of eggs and adults will result in improved pest management decisions and monitoring of these beneficial organisms. This study was conducted to determine flight activity patterns as well as preferred oviposition sites of lacewings on maize plants to facilitate time-effective searching for eggs. The daily flight activity pattern and flight height of lacewings were recorded and sweep-net samples were taken to determine lacewing numbers in different adjacent vegetation types (maize, lucerne, natural veld). The preferred area of oviposition was determined by inspecting maize plants for lacewing eggs and recording the distribution of eggs on leaves. Chrysoperla pudica (Navas) was the predominant species in maize. Lacewings were most active between 16:00 and 22:00 and flew largely between 0.5 and 2.5 m above ground level. Oviposition occurred predominantly on leaves near maize ears. Data on spatial distribution of eggs facilitate monitoring of eggs numbers in maize cropping systems and is also of use in general pest management.

The influence of rainfall on the seasonal abundance and flight activity of the maize stalk borer, Busseola fusca in South Africa

This study attempts to demonstrate the extent to which seasonal fluctuations in the number of Busseola fusca (Fuller) moths can be explained by precipitation data. Daily flight activity is shown to be enhanced by cool, humid conditions and restricted by rain. Humidity was shown experimentally to be of importance in the survival of moths under laboratory conditions. It is suspected that the observed relationship between seasonal moth numbers and rainfall is an indirect one and that survival of moths is rather determined by the direct influence of humidity. More serious infestations can therefore be expected during years with favourable rains.

Um modelo integrado de simulação-otimização para a avaliação de um novo negócio de aeronaves de propriedade compartilhada

Este artigo descreve um modelo integrado de simulação-otimização para auxiliar na avaliação de uma nova operação de jatos de propriedade compartilhada, que surge na fase de planejamento de um novo negócio, quando é necessário avaliar localizações alternativas para as bases onde ficam os jatos (quantas e onde), assim como estimar a mínima frota requerida e a quantidade de viagens vazias (“deadhead”) que não geram receita. O problema de determinação da frota ótima e alocação das aeronaves aos voos é modelado como um problema de fluxo em rede espaço-tempo de mínimo custo, com base em demandas diárias de vôos geradas a partir de simulação de Monte Carlo. O modelo foi implementado em ambiente de planilha Excel com automatização de todos dos procedimentos de simulação e de montagem e resolução do modelo de otimização, de tal modo que os dados possam ser alimentados, atualizados e modificados, e os modelos processados por qualquer pessoa sem conhecimento ou domínio de pesquisa operacional.

Strain- and sex-specific differences in daily flight activity and the circadian clock of Anopheles gambiae mosquitoes

Anopheles gambiae, the primary African malaria vector, is currently speciating into two incipient species, the so-called “molecular forms” M and S. While some geographic areas may contain only one form, in many areas both forms are found coexisting, but reproductively isolated. It appears that spatial segregation of mating swarms may contribute significantly to reproductive isolation as in many locales single-form swarms exist almost exclusively even though they are in close geographic proximity. The mechanism causing this spatial segregation is not well understood. Here, we compare the locomotor flight activity of M and S form male and female An. gambiae mosquitoes with the goal of identifying potential strain-specific temporal differences that could potentially serve as a mating barrier. We use an infrared beam break method to monitor flight activity of individual mosquitoes with a minute-to-minute time resolution under both LD cycle and constant dark conditions. We compare daily total flight activity, activity onset, peak in early nocturnal activity, the build up of dusk-related activity, and the free-running circadian period length. Our investigations revealed strain- and sex-specific differences in total daily activity. In both forms, males commenced nightly flight activity earlier than females, and this corresponded with a significantly shorter circadian period length in males compared to females. We note strain-specific differences in this response to dusk as males of the M form have a pronounced build up in flight activity relative to the S form males prior to complete darkness. This is likely driven by a differential response to the decreasing light intensity at dusk. We hypothesize that this behavioral difference could be a temporal factor contributing to the assembly of single-form swarms.

Diversity ofStomoxysspp. (Diptera: Muscidae) and diurnal variations of activity ofStomoxys indicusandS. Calcitransin a farm, in Wang Nam Khiao District, Nakhon ratchasima Province, Thailand

A study of species diversity of Stomoxys spp. and diurnal variations of activity of the most abundant was performed during a one year period at a local dairy cattle farm in Wang Nam Khiao District, Nakhon Ratchasima Province, Thailand. Four species of stomoxyine flies were morphologically identified, including Stomoxys indicus Picard 1908, S. calcitrans (Linnaeus 1758), S. sitiens Rondani 1873 and S. uruma Shinonaga and Kanao 1966. The most common species were S. indicus (50.2%) and S. calcitrans (49.5%). S. sitiens and S. uruma were found in small proportions (< 1%). The number of flies captured was significantly different among the three seasons with the greatest number in the rainy season (mean = 66%; df = 2, P < 0.05). The variations of diurnal activity were observed during different period of times (06:00 to 18:00) during three seasons. Both sexes of S. indicus and males of S. calcitrans showed unimodal activity pattern in cool and summer seasons. But a bimodal activity pattern was recorded in rainy season. For females S. calcitrans, a unimodal peak of activity was observed in cool season and a constant variation of activity all along the day in summer and rainy seasons, with an increase from the morning to the evening. A better understanding of stomoxyine fly behavior, especially the daily flight activity, can assist in prioritization and design of appropriate vector prevention and control strategies.

Seasonal pattern of daily activity of Aedes caspius, Aedes detritus, Culex modestus, and Culex pipiens in the Po Delta of northern Italy and significance for vector-borne disease risk assessment

The increasing concern about vector-borne diseases such as West Nile disease in northern Italy motivated our analysis of data on the mosquito fauna and the seasonal and daily flight patterns collected in 1998 in the Po Valley. Collections were performed once a week from May to November, with human landing collections and CO(2) traps. Culex pipiens was present from July to October and showed a clearly unimodal nocturnal flight habit. Culex modestus appeared in July-August and showed a bimodal flight pattern, (main peak during the evening and a minor one in the morning). Aedes caspius was present from May to November (highest densities in July-August) and showed a bimodal flight pattern with a major crepuscular peak and a minor dawn peak in the morning. Aedes detritus was the most abundant species in May, with a crepuscular sharply bimodal flight pattern, particularly according to human landing collections. Sunset and sunrise time, in combination with the solar phase (that determines daylight duration and its trend of changing) were the main factors affecting flight behavior. Temperature, relative humidity, and wind speed differently affected the flight behavior of mosquito females according to the species.

Relationship between civil aircraft noise and community annoyance near Dubai International Airport

According to Airport Council International (ACI) traffic statistics for 2002, Dubai International Airport is the second fastest growing airport in the world. In 2007, it catered to more than 36 million passengers, with approximately 1,000 daily flight events, including takeoffs and landings. In this paper, we report the first assessment of community annoyance caused by civil aircraft noise exposure at nine sites around Dubai International Airport (United Arab Emirates). Our aim is to assess the relationship between aircraft noise levels and annoyance responses in Dubai. To accomplish our goal, we have adapted the WECPNL and Ldn as the aircraft noise indices in Dubai, and the percentage of highly annoyed responses (%HA) has been used to assess the dose–response relationship of aircraft noise. %HA was obtained using social surveys that were carried out at nine sites within close proximity of the airport utilizing the ISO/TS 15666-2003 questionnaire. Subjects ranging between 20 and 65 years in age were randomly selected. Results show that 41% of the respondents said that they are highly annoyed, a percentage considered high but in agreement with similar studies carried out near major airports in other countries.

Aircraft Maintenance Planning Using Fuzzy Critical Path Analysis

Abstract Aircraft's availability is certainly one of the most important features of modern avionic industry. The aircraft maintenance scheduling is one of the major decisions an airline has to make during its operation. When an aircraft maintenance event occurs, the overhaul tasks management process requires the execution of all tasks to perform and has to guarantee the on-time aircraft delivery and the respect of the daily flight schedule. Though maintenance scheduling comes as an end stage in an airline operation, it has potential for cost savings. Maintenance scheduling is an easily understood but difficult to solve problem. Given a flight schedule with aircraft assigned to it, the aircraft maintenance-scheduling problem is to determine which aircraft should fly which segment and when and where each aircraft should undergo different levels of maintenance check. The objective of this paper is to minimize the aircraft maintenance planning time and to show how to create a plan with critical path analyses ...

Balloon-borne air traffic management (ATM) as a precursor to space-based ATM

The International Space University—Balloon Air traffic control Technology Experiment (I-BATE 1 1 I-BATE: International Space University—Balloon Air traffic control Technology Experiment. ) has flown on board two stratospheric balloons and has tracked nearby aircraft by receiving their Automatic Dependent Surveillance-Broadcast (ADS-B) transmissions. Air traffic worldwide is facing increasing congestion. It is predicted that daily European flight volumes will more than double by 2030 compared to 2009 volumes. ADS-B is an air traffic management system being used to mitigate air traffic congestion. Each aircraft is equipped with both a GPS receiver and an ADS-B transponder. The transponder transmits an equipped aircraft's unique identifier, position, heading, and velocity once per second. The ADS-B transmissions can then be received by ground stations for use in traditional air traffic management. Airspace not monitored by these ground stations or other traditional means remains uncontrolled and poorly monitored. A constellation of space-based ADS-B receivers could close these gaps and provide global air traffic monitoring. By flying an ADS-B receiver on a stratospheric balloon, I-BATE has served as a precursor to a constellation of ADS-B-equipped Earth-orbiting satellites. From the ∼30 km balloon altitude, I-BATE tracked aircraft ranging up to 850 km. The experiment has served as a proof of concept for space-based air traffic management and supports a technology readiness level 6 of space-based ADS-B reception.

Are mist nets a menace for threatened insects? A first attempt to gather quantitative data

We attempt to identify the threat to flying beetles imposed by mist nets deployed for bird studies in an area of Mediterranean mosaic of evergreen scrub and deciduous forest in Italy. The present paper is the first attempt to identify the non-target species which die in these artificial traps. A large number of large scarab beetles was entangled in mist nets during a complete ringing session. The seasonal trend of beetle populations and their daily flight activity were also recorded. The results lead us to suggest that the populations of some threatened dung beetles can be impoverished at local level and represent a bycatch of mist net techniques, especially in early spring and at sunrise, when their swarming and reproductive activity is high. When summed with other factors affecting these beetles, such as habitat loss and fragmentation, this tool may represent a threat for vulnerable insect populations. Trapping effects may also represent a depletion of food resource for some insectivorous birds. For these reasons we recommend cooperative research between ornithologists and entomologists to fully study the bycatch effects of mist netting on flying insects and their effects on food availability for insectivorous birds.

Estimating unconstrained customer choice set demand: A case study on airline reservation data

A good demand forecast should be at the heart of every Revenue Management model. Yet most demand models do not incorporate customer choice behavior under offered alternatives. We are using the ideas of customer choice sets to model the customer's buying behavior. The demand estimation method, as described in Haensel and Koole (2011), is based on maximum likelihood and the expectation maximization (EM) algorithm. The main focus of the paper is the application case on real airline reservation data. The reservation data, consisting of the airline's daily flight offers, is used to unconstrain the underlying customer demand in terms of price sensitivity. Using this demand information per choice sets, the revenue manager obtains a clear view of the real underlying demand.

The diurnal flight activity and influential factors of Frankliniella occidentalis in the greenhouse

Abstract The daily flight activity of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) was examined using color, yellow‐light and chemical attractant traps in a cucumber greenhouse and under controlled laboratory conditions. In the greenhouse, flying thrips were most abundant between hours 08:00–10:00, declined at mid‐day, and then slightly increased during hours 14:00–16:00; however they decreased to a very low level at 18:00. The use of light traps showed no thrip flight activity during the night. The total number of thrips that flew onto cards on rainy or cloudy days was higher than that on sunny days. We reconfirmed that traps treated with attractant attracted 4.0–9.4 times more thrip than the untreated traps. Under laboratory controlled conditions, thrip flight activity was highest under light intensity between 4 000 and 6 000 lux, air temperature of 28°C, and RH of 70%. In addition, starved thrips flew more readily than non‐starved thrips.

Light-attraction flight of the giant water bug, Lethocerus deyrolli (Hemiptera: Belostomatidae), an endangered wetland insect in East Asia

The giant water bug, Lethocerus deyrolli, is an endangered wetland insect found throughout East Asia. In 2006, the light-attraction flight of L. deyrolli was studied in Gyodong Island, Korea, using artificial light. The flight of L. deyrolli was observed from early June to late October, and two peaks in the numbers of attracted insects were noted in the middle of June and September. L. deyrolli begins to exhibit flight behaviour at a daily mean air temperature of 15°C and above, but optimal flight temperatures for the insect are between 17°C and 19°C, with a wind speed of less than approximately 1.8 m/sec and a relative humidity of around 80%. The length of daylight did not substantially influence the flight pattern. Daily flight occurred principally between 9 pm and 10:30 pm. L. deyrolli individuals attracted by the artificial light were frequently consumed by magpies or house rats. It appears most probable that artificial lights, such as street lights and tennis court lights, constitute a critical factor in the local extinction of L.deyrolli.