The marketing literature deals inadequately with markets which show characteristics of both consumer and industrial markets. In this work such markets are called hybrid markets. The research attempts to find an appropriate research approach for the short haul business related air travel market, which has hybrid market characteristics. Recent studies of the business travel market (Stephenson and Fox, 1987, Toh and Hu. 1988 and 1990) have investigated corporate and traveller attitude towards frequent flier programmes (see Glossary). However, as yet the airline marketing literature has not investigated the role the purchasing organisation (the employer of the traveller) has to play in a decision to purchase business related air travel. Market segmentation is selected as a suitable tool to investigate the business travel market. However, a review of the literature on segmentation for both consumer and industrial products reveals that an approach suited to the characteristics of this market is not available. Consequently a two stage research approach for hybrid markets is developed. A case study of nine companies in the first stage of the research is used to develop an understanding of corporate involvement in the purchase of business air travel, and identifies three key stakeholder groups in the purchase. They are the traveller, the travel organiser, and the 'organisation'. The second stage of the research collects data on the stakeholders. Traveller data on the importance of product elements in the purchase are used in a benefit segmentation of the market. The attitude data from 827 business travellers is analysed by factor analysis to identify six principal purchase benefits. These six benefits account for 60.6% of the variance in the data. Six factor scores for each respondent are calculated and then investigated by ak means iterative partitioning cluster analysis. A robust three cluster solution is discovered; i. e. three benefit segments are present in the short haul business travel market, based on traveller attitude. Cross-validation tests are carried out to test the stability of this solution. The three segments are investigated to evaluate the influence in the purchase decision of other organisational stakeholders. Differences between segments are found in the travel policy of the employing organisation, class of travel allowed to travellers, and purchase behaviour. The research indicates that for hybrid markets such as business travel, the role of the employing organisation may be important in purchase decisions. Consequently, it is recommended that future reserach should assess corporate involvement in purchases of products that have both consumer and industrial elements. The evaluation of the influences of various stakeholder groups in purchase decisions in hybrid markets may reveal previously overlooked marketing opportunities.

Bees and wasps perform learning flights when departing their nest for the first few times or a newly discovered food source. Several studies have described the occurances and structure of these flights in several species, but few have examined how the insects systematically vary the characteristics of their learning flights in various conditions in order to aid the acquisition of visual information. This is best done in a species where individuals and nests can be easily manipulated and tested repeatedly. The aim of this thesis was therefore to investigate learning flights in bumblebees, where we have a good understanding of the structure and variability of flights from previous work and can design controlled experiments. I explored the similarities and differences of learning flights of workers and male bumblebees, observing their departures from the nest or an artificial flower. A second objective was to examine how differences in the learning flights affect the bumblebees’ ability to return the learnt location. The experiments were conducted inside a large greenhouse, under natural light regimes, with two large tables placed far apart, one for simulating the ground from which bees emerged when departing their nest, and the other representing a feeding site with an artificial flower. Female bumblebees performed shorter learning flights when leaving a flower than when leaving their nest, although both locations displayed similar visual scenes. At both locations, the duration and trajectory length of learning flights decreased over successive visits, but the decrease was faster at the flower location than at the nest. Bumblebees fixated both their nest and the flower during their learning flights as well as the landmarks available around the two locations, which suggests that they learned the position of the goal relative to these landmarks. When the nest and the flower were hidden and only three cylinders were shown as landmarks in tests, bees searched as accurately for the nest as for the flower. However, they were more persistent when searching for the nest than for the flower, which was not predicted from the variation of learning flights at the nest and flower locations. Another situation in which bumblebees varied the characteristics of their learning flights, but without an impact on their performance when recalling the learnt information, was after visiting flowers filled with low and high sucrose rewards. The bees performed longer learning flights after drinking at a highly rewarded flower. When departing a poorly rewarded flower, bumblebees did not fixate the flower during their learning flights. Nevertheless, the bees were able to return to both the poorly rewarded flower and the highly rewarded flower equally fast. Given the above findings, it is not evident how different durations or trajectory lengths of bumblebee learning flights might be linked to variations in learning of goal locations. Finally, I show that bumblebees of either sex decide to perform learning flights at locations that are of importance to them. Whilst the female workers always performed learning flights when departing their natal nest, the males did not and simply flew away in a straight line. However, when leaving a flower, the males did perform learning flights with characteristics similar to those of the females’ learning flights. They were also able to return to the flower, showing similar approach trajectories as workers. The thesis discusses these findings in the light of ideas and hypotheses that are linked to differential investment in learning which were observed in the various conditions here. It is also discussed why bumblebees used fixations in different ways when learning about the visual environment surrounding goals that are important to them. Whilst many results are parsimonious with the requirements for learning and active flight control to aid the acquisition of visual information, motivation also seems to play a role in varying the occurances and features of learning flights, such as seen in the bees’ greater persistence to search for their nest than for a flower.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This thesis presents research contributing towards the automatic control of formation flight for commercial airliners. The motivation behind this research is to ultimately reduce fuel consumption of the trailing airliner through the utilisation of the aerodynamic coupling interactions between the trailing airliner and the wake vortices of the leading airliner. A traditional model for an airliner in isolated flight is developed and expanded to include formation flight interactions as functions of the vertical and lateral separation between the trailing and leading airliners. A trim analysis is done, and resulting actuator trims are presented over ranges of lateral and vertical separation. Regions of reduced throttle setting are identified, as well as risks and challenges for maintaining formation within these regions. These regions comprise of a potentially risky and challenging region, coined the "sandwich region"; as well as a safer, more practically viable region, coined the "outer region". The former is a narrow region sandwiched between two regions that are untrimmable with respect to maximum aileron deflection, whereas the latter is only constrained by an inboard untrimmable bound, but has less significant drag reduction. Subsequently, a state space representation is constructed, and a linear dynamics analysis follows. It is determined that the trimmed, uncontrolled trailing airliner is naturally unstable; hence a flight control system is required for stability. Furthermore, the analysis revealed that the dynamics stay essentially constant, especially for conventional modes, within the outer region. In the sandwich region however, the dynamics change much more drastically. Next, a control system for the conventional airliner is designed based on the available information of current representative fly-by-wire systems; and its performance is analysed in formation flight scenarios by means of both linear and non-linear simulations. It is found that, given sufficiently high control law gains, particularly for lateral controllers, the conventional architecture is sufficient for maintaining formation. Additional structures are suggested, such as saturation elements to limit the lateral separation rate and acceleration; and a state machine controller, with states for entering and exiting the wake vortices. Following this, a robustness analysis was done by once again evaluating the linear dynamics over ranges of lateral and vertical separation; this time with the flight controllers augmented into the linear models. The robustness analysis proved that the controllers are robust against lateral and vertical separation perturbation, at least in the outer region. Finally, a series of non-linear simulations prove the success of the control system in maintaining formation in various atmospheric turbulence conditions. Furthermore, the trailing airliner consistently has a reduced throttle setting, though with greater dynamic throttling compared to the leading airliner. Lastly, it is determined that the standard deviations of the control surface defection of the trailing airliner are in the same order of magnitude as those of the leading airliner in simulations with moderate turbulence. Interestingly, it is found that the elevator deflection of the trailing airliner has a lower standard deviation than that of the leading airliner, possibly due to the leading airliner carrying the burden of regulating the formation's altitude. / AFRIKAANSE OPSOMMING: Hierdie tesis handel oor navorsing wat 'n bydrae maak tot die outomatiese vlugbeheer van kommersiële passasiersvliegtuie in formasievlug. Die navorsing is gemotiveer deur die potensiële vermindering in die brandstofverbruik van die volgervliegtuig wat verkry kan word deur voordeel te trek uit die aerodinamiese koppeling tussen die volgervliegtuig en die nasleurvortekse van die voorste vliegtuig. 'n Tradisionele vlugmeganika model vir 'n passasiersvliegtuig is ontwikkel en uitgebrei om formasievluginteraksies in te sluit, as funksies van die vertikale en laterale skeidingsafstande tussen die volgervliegtuig en die voorste vliegtuig. 'n Ewewig-analise is uitgevoer, en die nodige ewewig-instellings is bereken oor die bereik van moontlike laterale en vertikale skeidingsafstande. Twee gebiede van verminderde enjin-krag instellings is gedentifiseer, en die risikos en uitdagings verbonde aan formasievlug in hierdie gebiede is beskou. Twee gebiede is uitgeken: 'n uitdagende, potensieel gevaarlike gebied, genoem die "sandwich" of "ingeperkte" gebied; en 'n veiliger, meer lewensvatbare gebied, genoem die "outer" of buitenste gebied. Die "ingeperkte" gebied is 'n baie nou gebied wat ingedruk is tussen twee ewewig-oninstelbare gebiede, waar aileron de eksie instellings vereis word wat die maksimum moontlike de eksies oorskry. Die "buitenste" gebied is 'n gebied wat net aan die binnekant begrens word deur 'n ewewig-oninstelbare gebied, maar wat nie so 'n groot besparing in brandstofverbruik bied as die "ingeperkte" gebied nie. Vervolgens is 'n toestandsveranderlike voorstelling van die vlugdinamika afgelei, en 'n dinamiese analise is uitgevoer. Die dinamiese analise het gewys dat die ewewig-ingestelde, onbeheerde vliegtuig natuurlik onstabiel is, en dat 'n vlugbeheerstelsel benodig word om vlugstabiliteit te verseker. Daarby het die analise ook onthul dat die vlugdinamika baie min verander oor die bereik van die "buitenste" gebied, maar dat die vlugdinamika baie meer drasties verander oor die bereik van die "ingeperkte" gebied. 'n Konvensionele vlugbeheerstelsel vir die vliegtuig is volgende ontwerp, gebaseer op beskikbare inligting oor die argitektuur van tipiese "fly-by-wire" beheerstelsels wat tans op passasiersvliegtuie gebruik word. Die prestasie van die konvensionele vlugbeheerstelsel in formasievlugtoestande is ontleed deur middel van beide lineêre en nie-lineêre simulasies. Die simulasies het gewys dat die konvensionele vlugbeheerargitektuur in staat is om formasievlug te handhaaf, gegee dat voldoende hoë beheeraanwinste gebruik word. Bykomende strukture is voorgestel, insluitendend versadigingselemente om die koers en versnelling van die laterale skeidingsafstand te beperk; en 'n toestandsmasjien-beheerder, met toestande om die nasleurvortekse binne te gaan en te verlaat. 'n Robuustheidsanalise is ook gedoen, deur die geslotelusdinamika met die beheerders ingesluit te analiseer oor die bereik van laterale en vertikale skeidingsafstande. Die robuustheidsanalise het gewys dat die beheerders wel robuust is oor die bereik van beide laterale en vertikale skeidingsafstande, ten minste in die "buitenste" gebied. Ten slotte is 'n omvattende reeks nie-lineêre simulasies uitgevoer om die vermoë van die vlugbeheerstelsel om formasievlug te behou te bevestig in 'n verskeidenheid van turbulensietoestande. Die simulasies het verder gewys dat die volgervliegtuig deurgaans 'n verminderde enjin-krag instelling het, maar met aansienlik meer dinamiese enjin-krag instelling variasies vergeleke met die voorste vliegtuig. Laastens het die simulasies gewys dat die standaard afwykings van die volgervliegtuig se beheeroppervlakde eksies van dieselfde ordegrootte is as dié van die voorste vliegtuig. Interessant genoeg is bevind dat die elevator defleksies van die volgervliegtuig 'n laer standaardafwyking het as dié van die voorste vliegtuig, waarskynlik omdat die voorste vliegtuig die groter las dra om die formasie se hoogte te reguleer.

<div> <p>Calibration of crop models is an expensive and time intensive procedure, which is essential to accurately predict the possible crop yields given changing climate conditions. One solution is the utilization of unmanned aircraft systems (UAS) deployed with Red Green Blue Composite (RGB), and multispectral sensors, which has the potential to measure and collect in field biomass and yield in a cost and time effective manner. The objective of this project was to develop a relationship between remotely sensed data and crop indices, similar to biomass, to improve the ability to parametrize crop models for local conditions, which in turn could potentially improve the quantification of the effect of hydrological extremes on predicted yield. An experiment consisting of 750 plots (350 varieties) was planted in 2018, and a subset of 18 plots (9 varieties) were planted in 2019. The in-situ above ground biomass along with multispectral and RGB imagery was collected for both experiments throughout the growing season. The imagery was processed through a custom software pipeline to produce spectrally corrected imagery of individual plots. A model was fit between spectral data and sampled biomass resulting in an R-square of 0.68 and RMSE of 160 g when the model was used to estimate biomass for multiple flight dates flights. The VIC-CropSyst model, a coupled hydrological and agricultural system model, was used to simulate crop biomass and yield for multiple years at the experiment location. Soybean growth was parametrized for the location using CropSyst’s Crop Calibrator tool. Biomass values generated from UAS imagery, along with the in-situ collected biomass values were used separately to parametrize soybean simulations in CropSyst resulting in very similar parameter sets that were distinct from the default parameter values. The parametrized crop files along with the default files were used separately to run the VIC-CropSyst model and results were evaluated by comparing simulated and observed values of yield and biomass values. Both parametrized crop files (using in-situ samples and UAS imagery) produced approximately identical results with a max difference of 0.03 T/Ha for any one year, compared to a base value of 3.6 T/Ha, over a 12-year period in which the simulation was ran. The parametrized runs produced yield estimates that were closer to in-situ measured yield, as compared to unparametrized runs, for both bulk varieties and the run experiments, with the exception of 2011, which was a flooding year. The parametrized simulations consistently produced simulated yield results that were higher than the measured bulk variety yields, whereas the default parameters produced consistently lower yields. Biomass was only assessed for 2019, and the results indicate that the biomass after parametrization is lower than the default, which is attributed to the radiation use efficiency parameter being lower in the parametrized files, 2.5 g/MJ versus 2.25 g/MJ. The improved accuracy of predicting yield is evidence that the UAS based methodology is a suitable substitute for the more labor intensive in-situ sampling of biomass for soybean studies under similar environmental conditions.</p> </div><p> <br></p>

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The aim of this study is to outline circumstances and reasons which caused a birth of an ambitious plan which enabled the USA to land a man on the Moon and return him safely to the Earth. The impact of this thesis is to chart individual pilot expeditions also from the eyes of real participants. One part of this study is a chapter dealing with astronauts' preparation and training. The thesis also reminds the fact that among people who landed on the Moon was also the astronaut of the Czech origin, Eugene A. Cernan. In the end the study deal with technology that helped to include program Apollo among the greatest events of the 20th century.

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O turismo tem apresentado uma demanda mundial cada vez maior e, por conseguinte, há uma crescente necessidade de preservar o meio ambiente com vistas às gerações futuras. O geoturismo e a roteirização, são ferramentas que podem ser utilizadas para este fim. Este trabalho visa, portanto, integrar dados turísticos, através do Sensoriamento Remoto com dados altimétricos representados por um Modelo Digital de Elevação - MDE. Desta forma, esta sistemática permite desenvolver um ambiente virtual onde o usuário pode realizar vôos cênicos em 3D (terceira dimensão) sobre o município de Três Cachoeiras e realizar, com isso um planejamento eficaz de suas atividades turísticas antes mesmo de ir a campo. Com a imagem de alta resolução espacial IKONOS (1m) sobreposta ao MDE é possível caracterizar a região e definir critérios, como por exemplo, a declividade do terreno para avaliar cada percurso. Estas ferramentas permitem, portanto, o estabelecimento de critérios de deslocamento e aos níveis de dificuldade para cada percurso. Os dados de campo, bem como aqueles provenientes da análise das imagens orbitais e do MDE, resultaram em uma roteirização turística sobre dois temas distintos: o Geoturismo e o Turismo Rural. / The tourism has presented a world-wide demand (2008). Representing an increasing necessity to preserve the environment with sights to the future generations, by the geotourism and the route planning, as well as the scientific research. This work aims at, therefore, to integrate tourist and de Remote sensing with altimetric data, represented by a Digital Elevation Model - DEM. In such a way, this systematics, allows to develop a virtual environment where the user can to visualize through scenic flights in 3D (third dimension) the city of Três Cachoeiras and make an efficient planning of tourist activities before exactly to go the field. With high resolution space image IKONOS (1m) overlapped to the DEM, is possible to characterize the region and to define criteria, as for example, the declivity of the land for evaluate each passage. These tools allow the establishment of criteria of displacement and the levels of difficulty for each passage. The field data, as well as those proceeding from the analysis of the orbital images and the DEM, had resulted in a touristic route on two distinct subjects: the Geotourism and the Rural Tourism.