Dissertations / Theses on the topic 'Directional mapping'

This study combines passive directional dust monitoring methods with ICP-MS analysis, binary mixing modelling and geostatistical modelling to generate dust dispersion maps, enabling a record of Air Pollution Control residue (APC) dust dispersion on and around a hazardous waste landfill site for a complete calendar year. This is therefore, the first study of nuisance dust dispersion on such a scale, using these methods, and the first time these methods have been used in conjunction to accurately visualise dust dispersion data over time. The proportion of APC in fugitive dust at and around the Wingmoor Farm hazardous waste landfill site near Bishop’s Cleeve, Gloucestershire, UK, was quantified and mapped using passive directional samplers, which were deployed both on the site and in farmland to the north and north-east. Samples from 19 monitors, collected fortnightly over the year, were analysed for Absolute Area Coverage (AAC) and Effective Area Coverage (EAC) prior to HF and HNO3 digestion and analysis by ICP-MS. Following geochemical characterisation of the two key “end-members”, background soils (sand and gravel, and clay) and APC, Ca/Fe and Mn/Pb mixing models were developed providing a means of determining the proportion of APC in each sample. Sample proportions derived from each mixing model were mapped using both variograms and kriging, supported through ISATISTM, to build a model of both general dust and APC dispersion over a square kilometre for the year. Meteorological conditions and movements on site were also recorded and their relationships with dust levels in the surrounding area analysed. APC was found at off-site monitoring locations throughout the year, however at far lower levels than previously assumed by prior modelling exercises. The maps presented a visualisation of dust dispersion on- and off-site, demonstrating the viability of this methodology for modelling both fugitive general dust, and, in this case, APC. In combination with the other data collected on-site, factors affecting the dispersion of both general dust and APC were identified. The development of this modelling and mapping method provides a novel, robust and cost-effective technique for both representing and understanding the dispersion of APC, delivering a useful tool for practical application by industry, local government and in the field of Environmental Forensics.

Abstract Plants and animals colonized Northern Europe after the last Ice Age from different refugia, not covered by the ice sheet. Many plants, such as the northern rock cress (Arabidopsis lyrata ssp. petraea) adapted to the short growing season in the North. We thus expect that colonization of the new environment was accompanied by directional selection for traits conferring this adaptation. In this thesis I studied whether recent directional selection can be detected in two important genes, PHYTOCHROME A (PHYA) and FLOWERING LOCUS C1 (FLC1), related to the flowering time pathway. To detect directional selection, I compared DNA sequence variation from the samples of a southern (Plech, Germany) and a northern (Spiterstulen, Norway) population. I also studied the current response potential to changing conditions in the marginal Spiterstulen population. Adaptation potential was characterized by assessing plasticity and amount of additive genetic variation, focusing on flowering traits. In addition, associations of 21 flowering time candidate genes for phenological and fitness traits were studied. There were several lines of evidence for recent directional selection in both candidate genes, PHYA and FLC1, in the northern Spiterstulen population Variation was strongly reduced around both genes and in addition they were highly differentiated between populations. In the Spiterstulen population there was a remarkable reduction in additive genetic variation for flowering traits, for instance when compared with morphological traits. On the other hand, phenological traits showed high plasticity. Some of the photoperiodic pathway genes showed association to flowering or reproductive fitness. The results suggest that directional selection during the colonization of the northern areas has impacted the two studied genes. Genetic changes were likely involved in altered photoperiodic and vernalization responses which might be adaptive for a short growing season. Further, directional selection was probably responsible for reducing additive genetic variation in flowering traits. Because there was only little genetic variation, adaptation to future environmental change of the marginal Spiterstulen population is likely to rely largely on plastic reactions to environmental signals, or tracking the environment by dispersal
Tiivistelmä Kasvit ja eläimet levittäytyivät Pohjois-Eurooppaan viimeisen jääkauden jälkeen mannerjäätikön ulkopuolella jääneistä refugioista. Useat kasvit, kuten idänpitkäpalko (Arabidopsis lyrata ssp. petraea) sopeutuivat pohjoisen lyhyeen kasvukauteen. On syytä olettaa, että suuntaava valinta vaikutti sopeutumisessa tärkeisiin ominaisuuksiin. Tässä väitöskirjassa tutkin voidaanko suuntaavan valinnan aiheuttamia jalanjälkiä löytää kahdesta tärkeästä kukkimisaikageenistä, FYTOKROMI A (PHYA) ja FLOWERING LOCUS C1 (FLC1) geeneistä. Tätä varten vertasin DNA sekvenssimuuntelua pohjoisessa (Norja) ja eteläisessä (Saksa) populaatiossa, kiinnittäen erityisesti huomiota geneettisen muuntelun määrään ja erilaistumiseen. Lisäksi tutkin miten Spiterstulenin reunapopulaatio voi vastata tulevaisuudessa muuttuvaan ympäristöön. Sopeutumispotentiaalia arvioitiin sekä fenotyyppisen plastisuuden että additiivisen geneettisen muuntelun määrällä. Lisäksi tutkin miten vaihtelu 21 kukkimisaikageenissä liittyy fenologisiin ja kelpoisuusominaisuuksiin. Useat merkit viittasivat siihen, että suuntaava valinta oli vaikuttanut kummassakin tutkitussa geenissä. Muuntelu oli vähentynyt voimakkaasti kumpaakin geeniä ympäröiviltä kromosomialueilta, jotka olivat myös selkeästi erilaistuneet. Additiivinen geneettinen muuntelu oli selvästi vähentynyt kukkimisominaisuuksissa verrattuna morfologisiin ominaisuuksiin, mahdollisesti suuntaavan valinnan johdosta. Kukkimisominaisuudet olivat kuitenkin plastisia. Jotkin valojaksoreitin geenit vaikuttivat sekä kukkimiseen että lisääntymiskykyyn. Nämä tulokset osoittavat että suuntaava valinta vaikutti kahteen tutkittuun geeniin pohjoiseen levittäytymisen aikana. Geneettiset muutokset liittyivät todennäköisesti muuttuneisiin valojakso-, ja vernalisaatiovasteisiin, jotka saattoivat edistää sopeutumista lyhyeen kasvukauteen. Koska geneettistä muuntelua oli vain hyvin vähän, fenotyyppisellä plastisuudella on todennäköisesti tärkeä rooli sopeutumisessa muuttuvaan ympäristöön Spiterstulenin reunapopulaatiossa

Many econometric analyses of commodity futures over the years have been performed using spot or front month contract prices. Using such daily prices without the consideration of the associated contract traded volumes is slightly erroneous because, in reality, traders will typically trade the ‘most liquid’ contract, that is, the contract with the largest average daily volume (ADV). The reason for this is in order to gain the best price when buying or selling. If this ‘true’ time series is to be considered, a mapping procedure is required to account for the price jumps at the time when a trader trades out of the expiring contract and enters the new front month contract. A key finding was that this effect was significant, irrespective of the size of the price jump, sometimes referred to as basis or roll and also due to the accumulated roll over a number of years corresponding to multiple contracts. It was also found that the mapping procedure has a significant effect on the time series and should hence always be employed if the realistic traded time series is to be considered. Given this phenomenon, algorithmically-traded commodities futures must necessarily employ such time series when creating metrics or considering an econometric analysis. The key findings include the importance of diversification in algorithmically-traded portfolios, utilising the AOM and PSI metrics. The mapping of data sets to create realistic ‘live-traded’ time series was found to be significant, while the optimal day of roll over prior to contract expiry was found to be related to the trading volumes for certain commodities. Other key findings include the causalities and spillovers within the metals sector where various relationships are evident once the results were processed and analysed, both pre and post mapping. Interestingly, the key relationships including bidirectional volatility and shock spillovers between the four key metals existed when the unmapped data was used however, many of the feedbacks within these relationships was lost when the mapped data sets were considered. A significant finding was therefore the consistent differences in findings between mapped and unmapped data sets attributed to the optimisation or favourability of the models (whether econometric or algorithmic). This is due to the unmapped data including roll or basis (which the models are fitted to) taking into account the roll or basis and utilising them in finding relationships between data sets. In the mapped data set (the time series seen by traders) the roll or basis is accounted for and hence the relationships found stand in real-time trading situations. The differences in the results show how the effect of mapping can be significant with unmapped data sets displaying results which will not exist in a real time traded time series.

In this study, an appearance reconstruction method based on extraction of material re&
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ectance properties of a three-dimensional (3D) object from its twodimensional (2D) images is explained. One of the main advantages of this system is that the reconstructed object can be rendered in real-time with photorealistic quality in varying illumination conditions. Bidirectional Re&
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ectance Distribution Functions (BRDFs) are used in representing the re&
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ectance of the object. The re&
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ectance of the object is decomposed into di&
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use and specular components and each component is estimated seperately. While estimating the di&
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use components, illumination-invariant images of the object are computed from the input images, and a global texture of the object is extracted from these images by using surface particles. The specular re&
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ectance data are collected from the residual images obtained by taking di&
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erence between the input images and corresponding illumination-invariant images, and a Lafortune BRDF model is &
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tted to these data. At the rendering phase, the di&
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use and specular components are blended into each other to achieve a photorealistic appearance of the reconstructed object.

Tato práce se zaměřuje na autonomní lokalizaci radiologických zdrojů v definované oblasti zájmu. Jejím cílem je vyvinout lokalizační strategie a platformu, na které je bude možné vyzkoušet. Platforma je sestavena z průzkumného robotu Orpheus-X3, scintilačních detektorů a přesného GNSS přijímače. Algoritmus pro vytváření mapy distribuce radiačního pole je rozšířen. Jsou představeny nové metody založené na směrové citlivosti navrhovaného detekčního systému. Počáteční průzkum oblasti zájmu je uskutečněn pomocí kružnicových trajektorií. Všechny algoritmy byly otestována jak simulacemi, tak reálnými experimenty. Dosažená přesnosti lokalizace je v řádu desítek centimetrů. Časová efektivita je použitím nových algoritmů zvýšena přibližně dvakrát až pětkrát. Jedním z~přínosů práce je vývoj modulárního systému, který může být přesunut a uzpůsoben na jiné platformy. Výhodou použitého systému je vysoký stupeň autonomie a bezpečnost pro lidského operátora.

Fyzikálně přijatelné osvětlení v reálném čase je často dosaženo použitím aproximací. Současné metody často aproximují globální osvětlení v prostoru obrazu s využitím schopností moderních grafických karet. Dva techniky z této kategorie, screen-space ambient occlusion a screen-space directional occlusion jsou popsány detailněji v této práci. Screen-space directional occlusion je zobecněná verze screen-space ambient occlusion s podporou jednoho difúzního odrazu a závislostí na směrové informaci světla. Hlavním cílem projektu bylo experimentování s těmito metodami. Pro uniformní distribuci náhodných vzorek pro obě metody byla použita Halton sekvence. Pro potlačení šumu je použita bilaterální filtrace, která bere do úvahy geometrické vlastnosti scény. Metody jsou dál zrychleny použitím nižších rozlišení pro výpočet. Rekonstrukce výsledků do původní velikosti pro vytvoření konečného obrazu je realizována pomoci joint bilateral upsamplingu. Kromě metod globálního osvětlení byly v práci použity aj metody pro mapování stínů a HDR osvětlení.

Dimmuborgir is thought to be a former rootless shield volcano, which was fed with lava from a nearby crater row, 2170 ± 38 calendar years before present. In this study, the orientation of striations on the sides of lava channels, collapse structures and lava pillars were measured to find out how the enigmatic ~2 km by 2 km volcanic structure at Dimmuborgir was drained. During one week of field work 149 striations were found and measured, with respect to their dip angle, dip direction and elevation. Their locations were recorded with a GPS (Global Positioning System) receiver. The orientations of the striations were visualized on Google Earth satellite images and on images from a Digital Terrain Model (DTM) of Dimmuborgir. Resulting visualizations show that Dimmuborgir was drained radially and in multiple stages. It is concluded that Dimmuborgir was drained towards the west, the northeast and the southeast. The drainage towards the west was channeled. The drainage towards the northeast and the southeast was radially inwards, towards the collapsed parts of Dimmuborgir.

The introduction of input devices with natural user interfaces in gaming hardware has changed the way we interact with games. Hardware with motion-sensing and gesture recognizing capabilities remove the constraint of interacting with games through typical traditional devices like mouse-keyboard and gamepads. This changes the way we approach games and how the game communicates back to us as the player opening new levels of interactivity. This thesis covers how eye tracker technology can be used to affect rendering effects in games.

Les compétences sont des objets de gestion complexes mais indispensables à l’employeur pour spécifier ses besoins et au travailleur pour tracer son profil. Agrégées en postes, emplois, métiers, elles forment des cadres transactionnels dans un espace constitué d’objets abstraits et de leurs liens. Cette thèse vise à affirmer la centralité d’un dispositif cartographique à travers l’examen : des bénéfices d’une mise au net de cet espace, notamment face à la transformation numérique ; du recours indispensable à un artefact médiateur technologique ; du rôle de cartographe, le maître d’oeuvre de la fonction RH, investie de la médiation et de la régulation sociales. La recherche s’appuie sur un parcours professionnel dans le domaine RH et, sur le plan méthodologique, croise les besoins de la gestion des compétences avec les apports de la cartographie moderne. Elle aboutit à une proposition méthodologique pour cartographier des espaces abstraits, appuyée par un démonstrateur internet SaaS
Skills are complex management objects which are essential to define employers’ needs and draw one’s profile and wishes. Aggregated in positions, jobs, professions, they form a transactional framework in a space of abstract artefacts and their links. This thesis aims to assert the centrality of a mapping device by examining: the benefits of a clearing of this space, especially trough digital transformation; the indispensable support of technological artefacts to help a person or a group, to identify, decide, evolve in this space; the role of cartographer to be taken by the human resources function. The research is based on a professional career in the field of human resources and methodologically, crosses needs around the notion of competence with the contributions of modern cartography (GIS, geomatics, data visualisation). It leads to a synthesis by the design of a SaaS platform demonstrator, and a cartographic methodology for abstract space

The statistics of the amplitude, time and angle of arrival of multipaths in an indoor environment are all necessary components of multipath models used to simulate the performance of spatial diversity in receive antenna configurations. The model presented by Saleh and Valenzuela, was added to by Spencer et. al., and included all three of these parameters for a 7 GHz channel. A system was built to measure these multipath parameters at 2.4 GHz for multiple locations in an indoor environment. Another system was built to measure the angle of transmission for a 6 GHz channel. The addition of this parameter allows spatial diversity at the transmitter along with the receiver to be simulated. The process of going from raw measurement data to discrete arrivals and then to clustered arrivals is analyzed. Many possible errors associated with discrete arrival processing are discussed along with possible solutions. Four clustering methods are compared and their relative strengths and weaknesses are pointed out. The effects that errors in the clustering process have on parameter estimation and model performance are also simulated.

碩士
國立交通大學
電機與控制工程系所
96
This study investigates robot localization and mapping using omni-directional images. A method is proposed to use an omni-directional camera to realize simultaneous localization and mapping (SLAM) algorithm based on extended Kalman filter (EKF). Because of the 360° field of view, an omni-directional camera is suitable for simultaneous localization and mapping (SLAM) for detecting and tracking environmental features. A new algorithm is developed adopting scale invariant feature transform (SIFT) method to match features in environment between two images. This thesis also presents a switching method of visual reference scans. In this method, reference scan can be added to a database or switched automatically among reference scans. These scans can be used repeatedly to reduce the complexity of extended Kalman filter (EKF). Experiments results show that the matching rate of landmark features is 90%. A long range indoor navigation experiment revealed that the proposed localization algorithm can help robot to navigate in indoor environment and build the features map simultaneously.

碩士
國立中央大學
遙測科技碩士學位學程
99
Radar interferometry is a powerful technique for extracting information about the Earth’s surface using the phase difference between the signals arriving at the sensor antenna during repeated observations from the same platform. However, the problematic issue is that since radar senses and measures in slant range, it does not tell whether the displacement comes from horizontal or vertical direction, namely, a directional ambiguity inherently exists. A method based on weighted least squares is proposed to resolve it by integrating both ascending and descending orbits in order to determine whether the deformation is of uplift type or of subsidence. The resolved deformation pattern into three directions is useful to understand the movement mechanism and also to facilitate the direct comparison with ground leveling or measurements. Assuming that all the measurements, whether descending or ascending, are uncorrelated and independent but with different phase variances depending on the coherence, best linear unbiased estimator may be derived. To better confirm the subsidence map derived from series ALOS-PALSAR image data takes, comparisons with the precision leveling survey were made. Excellent agreement was obtained on both the spatial pattern and scale at centimeter resolution. Both ascending and descending mapping results indicate that the maximum subsidence rate in that period as about 6.7 cm/yr (at an epicenter). It was suggested that reliable deformation estimate is contingent upon the combination of long-term and short-term observations using dual-beam SAR image data sets preferably at different inclination angles.

碩士
國立臺灣大學
電子工程學研究所
97
In this Thesis, we propose a performance-aware task mapping algorithm for BiNoC (bi-directional network-on-chip) architecture. The whole framework contains two phases: task clustering and task mapping. For a given task graph and a BiNoC topology, the task clustering phase partitions a task graph into appropriate clusters to minimize the system parallelization time. The task mapping phase employs an SA-based (simulated annealing-based) algorithm which maps clusters of TCG (task communication graph) to PEs (processing elements) injectively. The SA-based algorithm uses real execution time as the cost function and considers the negative effect caused by contentions. Since the channel direction is configurable in a BiNoC, our approach makes use of this characteristic to allocate channel admission to the communication demands and lead to a low system execution time. Experimental results show that, compared to other existing mapping approaches for performance-aware purpose, our approach achieves a significant decrease in packet latency.

碩士
國立交通大學
電機與控制工程系所
96
This thesis investigates simultaneous localization and mapping (SLAM) of an omni-directional mobile robot. A method is proposed to use an omni-directional camera to realize SLAM algorithm based on extended Kalman filter (EKF). This study focus on the use of 360° of view of the omni-directional camera to reduce the accumulative error from odometer and to achieve simultaneous localization and mapping of the omni-directional platform. The method of visual reference scans is adopted in this design. Features of previously visited places can be used repeatedly to reduce the complexity of extended Kalman filter. Experimental results show that the matching rate of landmark features is 93%. The localization error is less than 0.10m for traveling 16 meters of “8” shaped route. Indoor navigation experiments revealed that the proposed localization system can navigate the omni-directional robot in an indoor environment and build the feature map simultaneously.

Thesis (Ph.D.)--York University, 2006. Graduate Programme in Computer Science.
Typescript. Includes bibliographical references (leaves 266-281). Also available on the Internet. MODE OF ACCESS via web by entering the following URL: http://proquest.umi.com/pqdweb?index=0&did=1306835141&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1195136081&clientId=5220

碩士
逢甲大學
應用數學所
98
In computational field simulation, the techniques of adjusting grid are frequently used to obtain highly accurate numerical solutions. In the past, it is difficult to adjust the surface grids within three-dimensional space. In this thesis, we developed a new strategy that applies the technique of dimensionality reduction to overcome this problem. This new strategy can perform a bi-directional nonlinear mapping between three-dimensional surface and two-dimensional plane that can be applied to the study of adaptive grid, multigrid and so on. Either the structured surface grid or the unstructured surface grid, both can be mapped from three-dimensional space into two-dimensional space via Isomap which is based on manifold learning. The related position in two-dimensional data points will be kept the same as they are in its corresponding three-dimensional space. According to this relation, we can adjust the grid points directly in two-dimensional space. There are two kinds of methods for adjustment: one is the grid redistribution, the other is refining the grid locally. After adjusting strategy, bilinear interpolation (for structured grid) or barycentric interpolation (for unstructured grid) can be used to find the relation between the adjusted grid and the non-adjusted grid. And then the new three-dimensional surface grid can be constructed completely via this relation by remapping the adjusted plane grid into the original three-dimensional grid. This process can get the effect of adaptation.