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Estados ligados de Majorana em nanodispositivo com ponto quântico acoplado à cadeia de átomos em zigue zague sobre supercondutor topológico. / Connected states of Majorana in nanodispositivo with quantum dot coupled to the string of zigzag atoms over topological superconductor.BEIRÃO, Antonio Thiago Madeira 11 October 2018 (has links)
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Previous issue date: 2018-10-11 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A pesquisa em física da matéria condensada com isolantes e supercondutores topológicos tem contribuído muito para a caracterização das propriedades de superfície e de modos zero em nanofios. Investigamos teoricamente o transporte de elétrons através do ponto quântico em forma de T (PQ) com um único nível e spinless, conectado a uma cadeia em zigue zague e acoplado a um supercondutor p-wave, utilizando o método analítico recursivo de funções de green no equilíbrio. Este modelo é uma extensão da cadeia de Kitaev para uma rede triangular de tamanho finito com três, quatro e cinco sitios. Observamos que modos zero de Majorana podem ser sintonizados através dos parâmetros de acoplamento do dispositivo e a condutância linear mostra ambos os Estados Ligados de Majorana (MBS) na fase topológica e na fase topológica geral maximamente robusta. Este modelo mais realista permite a detecção de MBS através do controle dos parâmetros que governam o tunelamento eletrônico e pode ser útil para experimentos relevantes. / The research in condensed matter physics with insulators and superconductors topological has contributed greatly to the characterization of the surface properties and modes zero in nanowires. We investigate theoretically, through the recursive Green’s function approach, the electron transport through the T-shaped quantum dot (PQ) with a single level and spinless, connected to a zigue zague chain and coupled to a p-wave superconductor. This model is an extension of the Kitaev chain for a network triangular of finite-size with for three, four, and five sites. We find that the Majorana zero modes can be tuned through the coupling parameters of the device and the linear conductance show both the Majorana Bound States (MBS) in topological phase and in the general topological phase maximally robust. This more realistic model allows the detection of MBS through of the control of the parameters governing
the electronic tunneling and can be helpful for relevant experiments.
Keywords: Majorana Fermions, recursive Green’s function approach, Kitaev chain, class of electronic nanodevices, Quantum Dot, T-shaped, Qubit, Majorana Bound States (MBS).
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Triphenylamine-based hole transport materials for perovskite solar cellsFuentes Pineda, Rosinda January 2018 (has links)
The rapid development in perovskite solar cells (PSC) has generated a tremendous interest in the photovoltaic community. The power conversion efficiency (PCE) of these devices has increased from 3.8% in 2009 to a recent certified efficiency of over 20% which is mainly the product of the remarkable properties of the perovskite absorber material. One of the most important advances occurred with the replacement of the liquid electrolyte with a solid state hole conductor which enhanced PCE values and improved the device stability. Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)- 9,9'-spirobifluorene) is the most common hole transport material in perovskite solar cells. Nevertheless, the poor conductivity, low charge transport and expensive synthetic procedure and purification have limited its commercialisation. Triphenylamines (TPA) like Spiro-OMeTAD are commonly employed due to the easy oxidation of the nitrogen centre and good charge transport. Other triarylamines have similar properties to Spiro-OMeTAD but are easier to synthesise. The aim of this doctoral thesis is to investigate different types of hole transport materials in perovskite solar cells. Three different series of triphenylamine-based HTM were designed, synthesised, characterised and studied their function in perovskite solar cells. A series of five diacetylide-triphenylamine (DATPA) derivatives (Chapter 3) with different alkyl chain length in the para position was successfully synthesised through a five step synthesis procedure. A range of characterisation techniques was carried out on the molecules including; optical, electrochemical, thermal and computational methods. The results show that the new HTMs have desirable optical and electrochemical properties, with absorption in the UV, a reversible redox property and a suitable highest occupied molecular orbital (HOMO) energy level for hole transport. Perovskite solar cell device performances were studied and discussed in detail. This project studied the effect of varying the alkyl chain length on structurally similar triarylamine-based hole transport materials on their thermal, optical, electrochemical and charge transport properties as well as their molecular packing and solar cell parameters, thus providing insightful information on the design of hole transport materials in the future. The methoxy derivative showed the best semiconductive properties with the highest charge mobility, better interfacial charge transfer properties and highest PCE value (5.63%). The use of p-type semiconducting polymers are advantageous over small molecules because of their simple deposition, low cost and reproducibility. Styrenic triarylamines (Chapter 4) were prepared by the Hartwig-Buchwald coupling followed by their radical polymerization. All monomers and polymers were fully characterised through electrochemical, spectroscopic and computational techniques showing suitable HOMO energy levels and desirable optoelectrochemical properties. The properties and performance of these monomers and polymers as HTMs in perovskite solar cells were compared in terms of their structure. Despite the lower efficiencies, the polymers showed superior reproducibility on each of the device parameters in comparison with the monomers and spiro-OMeTAD. Finally, star-shaped structures combine the advantages of both small molecules, like well-defined structures and physical properties, and polymers such as good thermal stability. Two star-shaped triarylamine-based molecules (Chapter 5) were synthesised, fully characterised and their function as hole-transport materials in perovskite solar cells studied. These materials afford a PCE of 13.63% and high reproducibility and device stability. In total this work provided three series of triarylamine-based hole transport materials for perovskite solar cells application and enabled a comparison of the pros and cons of different design structures: small-molecule, polymeric and star-shaped.
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Apport de la morphométrie géométrique et de l'imagerie 3D intra-orale dans l'étude du shoveling des incisives centrales maxillaires / Contribution of geometric morphometry and intra-oral 3D imaging in the study of shoveling of human maxillary central incisorsCarayon, Delphine 19 December 2018 (has links)
Le shoveling de l'incisive centrale maxillaire est une caractéristique dentaire non-métrique utilisée en anthropologie comme indicateur des relations entre les populations. Ce trait morphologique dentaire est défini comme le degré d'élévation des crêtes mésiales et distales marginales sur la surface linguale des incisives maxillaires avec des formes plus prononcées renfermant une fosse. Plusieurs tentatives ont été faites pour classer et évaluer les différences de shoveling entre les populations humaines modernes et fossiles, en utilisant d'abord des approches descriptives détaillées et en élaborant par la suite des systèmes de notation ordinale des traits. A ce jour, la technique gold standard pour l'analyse du shoveling est basée sur une échelle ordinale de sept grades qui a été adaptée et intégrée à un système formel de notation des traits non métriques de la morphologie dentaire: le Arizona State University Dental Anthropology System (ASUDAS). Ce protocole standard est basé sur des plaques de plâtre de référence représentant les moulages de dents sélectionnées montrant un gradient d'expression d'un trait particulier. La notation ordinale, même si elle est contrôlée par des définitions strictes des caractéristiques, des références visuelles et l'expérience de l'observateur, comprend une part inévitable de subjectivité. De plus, les supports d'information conventionnels utilisés par ASUDAS peuvent entrainer des pertes d'information dans le temps. Dans un premier temps, nous avons élaboré une nouvelle approche morphométrique quantitative pour évaluer la variation du shoveling des incisives centrales maxillaires humaines modernes (UI1). Nous avons analysé par imagerie virtuelle 87 UI1 humaines modernes (Europe, Afrique, Asie) et les 7 UI1 de la plaque de référence ASU-UI1 en utilisant la morphométrie géométrique et le positionnement de points de repères glissants. Les résultats de la répartition du shoveling en fonction des populations selon notre nouvelle méthode morphométrique sont en étroite corrélation avec la répartition du shoveling largement décrite dans la littérature. En outre, nos résultats ont mis en évidence certaines limites dans l'utilisation des plaques ASUDAS, laissant supposer qu'elles ne représentent pas nécessairement un gradient objectif d'expression de cette caractéristique dentaire non métrique. [...] / The shoveling of the maxillary central incisor is a non-metric dental characteristic frequently used in anthropology as an indicator of population relations for its taxonomic and phylogenetic relevance for many decades. This dental morphological feature is defined as the degree of elevation of the mesial and distal marginal ridges on the lingual surface of the maxillary incisors, canines and mandibular incisors, with more pronounced pit-like forms. From the 19th century until today, several attempts have been made to classify and assess the shoveling differences between fossil and modern human populations, first using detailed descriptive approaches and later developing ordinal feature notation systems. The standard gold technique for shoveling analysis is based on a seven-grade ordinal scale that has been adapted and integrated into a formal system for scoring non-metric features of dental morphology: the Arizona State University Dental Anthropology System (ASUDAS). This widely-used standard protocol is based on reference plaster plaques representing the casts of selected teeth showing a gradient of expression of a particular trait. Ordinal notation, even if controlled by strict definitions of characteristics, visual references, and observer experience, includes an inevitable element of subjectivity. Moreover, the conventional information support used by ASUDAS can lead to loss of information over time. Some researchers have attempted to reduce visual subjectivity by measuring the depth of lingual shoveling, but with little success in their results due to method accuracy problems. First, we developed a new quantitative morphometric approach to assess the shoveling variation of modern human maxillary central incisors (UI1). We analyzed by virtual imaging 87 modern human UI1 (Europe, Africa, Asia) and the 7 UI1 of the ASU-UI1 reference plaque using geometric morphometry and the positioning of sliding reference points. The results of the distribution of shoveling according to populations according to our new morphometric method are in close correlation with the distribution of shoveling widely described in the literature. In addition, our results showed some limitations in the use of ASUDAS plaques, suggesting that they do not necessarily represent an objective gradient of expression of this non-metric dental characteristic. [...]
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A Recreation and Ballistic Evaluation of Otto Schneeloch's Firearm Curiosity - The .307 TriangularShukitis, Amber Nicole 05 March 2014 (has links)
Otto Scheeloch's U.S. Patent No. 134,442 of 1872 describes a unique firearm that uses triangular bullets. The current research effort evaluates the ballistic performance of Otto's disclosure for the very first time. To achieve this goal it was necessary to seek out surviving artifacts and scour the historical record in search of all the parameters needed to meticulously recreate the curious triangular cartridges and the corresponding gun barrel, with its matching twisted triangular bore. Every aspect of the resulting reproduction ammunition was made to be as authentic as possible, including the use of vintage civil war era bullet lead, bullet grease of period recipe, and the correct type of black powder propellant. 3D CAD (SolidWorksTM) was employed in designing the components, while advanced rapid prototyping (FDM & DMLS) techniques and investment casting were used in the physical construction of the ammunition and barrel. The ballistics testing was performed from a shooting rest over a range of 10-feet. Data was obtained for five rounds using a chronograph, paper targets and ballistic gel. The triangular bullets proved to be surprisingly accurate, consistent, and stable in flight. Data was recorded for sectional density, ballistic coefficient, muzzle velocity and energy, group size and penetration.
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Finkalibriga projektiler, RSV och penetrerande stridsvagnsminor : vad krävs av ett ballistiskt skydd för att undvika penetration från dessa stridsdelar? / Small-caliber projectiles, shaped charged projectiles and penetrating anti-tank mines : what is required of a ballistic protection to prevent penetration from these warheads?Petersson, Jimmy January 2010 (has links)
<p>Detta arbete syftar till att undersöka vilket konventionellt ballistiskt skydd som krävs för att undvika penetration från finkalibriga projektiler, RSV-stridsdelar samt penetrerande stridsvagnsmina. Arbetet tar sitt ursprung i en handbok utgiven av FMV där stridsdelar som kan förekomma i Afghanistan behandlas. Handboken anger data och prestanda för dessa stridsdelar och det är därifrån arbetet tar uppgifter om genomslagsförmåga för stridsdelen. Skyddsprinciper och verkansprinciper för stridsdelar hämtas i huvudsak från rapporter utgivna av FOI samt från litteratur utgiven av FHS. Arbetets beskrivande delar inleds med en redogörelse för homogena ballistiska skyddsmaterial av metall samt keramer. Därefter beskrivs verkans principer för finkalibriga projektiler, strålbildande RSV, projektilbildande RSV samt penetrerande stridsvagnsminor. Arbetet fortgår med en beskrivning av en finkalibrig projektil med kaliber 7,62*54R mm, hot av typen RPG-7 med tillhörande ammunition samt stridsvagnsmina TMK-2. Avslutningsvis presenteras resultat på vilket ballistiskt skydd som krävs för att skydda sig mot dessa stridsdelar samt en diskussion kring resultatet och alternativa lösningar på problemet. Det presenteras även några förslag på ny forskning inom området verkan och skydd.</p> / <p>This essay aims to investigate which conventional ballistic protection required preventing penetrationof small-caliber projectiles, shaped charged warheads and anti-tank mine. The essay takes its originin a handbook published by the Swedish Defense Material Administration, (FMV), where the warheads that can occur in Afghanistan are presented. The handbook present data of the warheads and it is from here information regarding the warheads penetration capabilities is taken. Effect principles and protection principles of the warheads are primarily gathered from reports published bythe FOI and from literature published by the National Defense College of Sweden, (FHS). The essays descriptional parts begin with an explanation of homogeneous ballistic protection materials fabricated in metal and ceramics. It then continues with a description of effect principles of small caliber projectiles, shaped charge projectiles, explosively formed projectiles and anti-tank mines. The essay then continues with a description of a small caliber projectile with caliber 7.62*54R mm, threats of RPG-7 type with its ammunition and the anti-tank mine TMK-2. In the end of the essay, results are presented according to the ballistic protection required to protect against the presented warheads, and a discussion of the result and alternative solutions to the problem.</p>
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Regional and local variation in plant species richnessDupré, Cecilia January 2001 (has links)
In this thesis, I examine the variation in plant species richness along gradients of productivity and disturbance in grasslands and forest habitats in southern Sweden, and I compare the documented patterns with theoretical predictions. Moreover, I evaluate the relative importance of habitat quality and habitat configuration for the occurrence of field layer species in deciduous forests. Finally, I present a new method for the determination of the regional species pool. To examine regional and local variation in plant species richness, I gathered data on species composition in plots of different size (0.001 - 1000 m2) in three vegetation types (deciduous forests, dry grasslands and coastal meadows) in four regions of southern Sweden (Öland, Gotland, Småland and Uppland). As predicted by the species pool hypothesis, differences in small-scale species richness of deciduous forests and dry grasslands were correlated with differences in the size of the regional species pool. Moreover, among plots large-scale diversity was predictive of small-scale diversity. Species diversity showed a hump-shaped relationship with productivity in forests, and was related to environmental heterogeneity and the size of the 'habitat-specific' species pool. In the two types of grassland examined, grazed sites were richer in species than abandoned sites. Moreover, both species composition and the representation of plants with different life-history characteristics differed between grazed and abandoned sites. As predicted by the intermediate disturbance hypothesis, species richness was highest at intermediate levels of grazing in coastal meadows. However, all the above patterns were scale-dependent, and not observed at all plot sizes. The occurrence of field layer species in deciduous forests was more strongly related to habitat quality (mainly soil factors) than to habitat configuration (forest area and isolation). Across species, low seed production, clonal reproduction and habitat specificity were negatively associated with isolation.
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Finkalibriga projektiler, RSV och penetrerande stridsvagnsminor : vad krävs av ett ballistiskt skydd för att undvika penetration från dessa stridsdelar? / Small-caliber projectiles, shaped charged projectiles and penetrating anti-tank mines : what is required of a ballistic protection to prevent penetration from these warheads?Petersson, Jimmy January 2010 (has links)
Detta arbete syftar till att undersöka vilket konventionellt ballistiskt skydd som krävs för att undvika penetration från finkalibriga projektiler, RSV-stridsdelar samt penetrerande stridsvagnsmina. Arbetet tar sitt ursprung i en handbok utgiven av FMV där stridsdelar som kan förekomma i Afghanistan behandlas. Handboken anger data och prestanda för dessa stridsdelar och det är därifrån arbetet tar uppgifter om genomslagsförmåga för stridsdelen. Skyddsprinciper och verkansprinciper för stridsdelar hämtas i huvudsak från rapporter utgivna av FOI samt från litteratur utgiven av FHS. Arbetets beskrivande delar inleds med en redogörelse för homogena ballistiska skyddsmaterial av metall samt keramer. Därefter beskrivs verkans principer för finkalibriga projektiler, strålbildande RSV, projektilbildande RSV samt penetrerande stridsvagnsminor. Arbetet fortgår med en beskrivning av en finkalibrig projektil med kaliber 7,62*54R mm, hot av typen RPG-7 med tillhörande ammunition samt stridsvagnsmina TMK-2. Avslutningsvis presenteras resultat på vilket ballistiskt skydd som krävs för att skydda sig mot dessa stridsdelar samt en diskussion kring resultatet och alternativa lösningar på problemet. Det presenteras även några förslag på ny forskning inom området verkan och skydd. / This essay aims to investigate which conventional ballistic protection required preventing penetrationof small-caliber projectiles, shaped charged warheads and anti-tank mine. The essay takes its originin a handbook published by the Swedish Defense Material Administration, (FMV), where the warheads that can occur in Afghanistan are presented. The handbook present data of the warheads and it is from here information regarding the warheads penetration capabilities is taken. Effect principles and protection principles of the warheads are primarily gathered from reports published bythe FOI and from literature published by the National Defense College of Sweden, (FHS). The essays descriptional parts begin with an explanation of homogeneous ballistic protection materials fabricated in metal and ceramics. It then continues with a description of effect principles of small caliber projectiles, shaped charge projectiles, explosively formed projectiles and anti-tank mines. The essay then continues with a description of a small caliber projectile with caliber 7.62*54R mm, threats of RPG-7 type with its ammunition and the anti-tank mine TMK-2. In the end of the essay, results are presented according to the ballistic protection required to protect against the presented warheads, and a discussion of the result and alternative solutions to the problem.
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Dödsfärd och livsrum : skeppssättningar och hussymbolik på den yngre bronsålderns gravfält i SydskandinavienSöderström, Ulrika January 2008 (has links)
Many archaeologists have been intrigued by how often symbolic houses of varying forms are used on the burialgrounds of the Scandinavian Bronze Age. Some scholars even claim that to deal with the dead did not mean to set them apart from the world of the living during this period. Since several examples show that there seem to be an active connection between the ship-setting and different types of symbolic houses, this study seek to demonstrate and interpret how the ideology behind these symbols vary between three regionally different Swedish areas: Halland, Småland and Gotland. The purpose is to show that the way chosen to shape the symbols materially not only had fundamental impact on the organization of the burialground itself, but also on how the surrounding world came to comprenhend and use them. This study suggests that even though the special shapes of the graves and the gravefield itself can carry meaning, the materialization of the monuments can be interpreted as incorporated in a practice of remembrance in where the individual shaping of the grave most probably formed part of a greater story.
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The Study of Expendiency & Benefit for Consumers Who Procure Vehicles from Second-hand Vehicles Vendors in A Propensity of Asymmetrical Information of Supply/Demand Market¡Xby way of examples of the market in Taiwan & JapanChen, Ching-kuo 31 August 2005 (has links)
The second-hand vehicle market in Europe, America, and Japan has entered the mature period and showed the following market characteristic:
1.Large business volume and has formed effect of scale
Volume of the second-hand vehicle business in developed countries is lot more than the volume of the new vehicle. Generally it is above a time. According to the summary statistics, the annual sales volume of American second-hand vehicle is already 2.5 times of its new vehicle sales volume, and the year sales volume of Japanese second-hand vehicle has continuously surpassed its new vehicle the sales volume for many years. Just because of huge second-hand vehicle market, the developed countries can maintain a stable and huge market of new vehicle market. The related data demonstrated that, in a mature auto market, the average of vehicle discard cycle is about 8 - 12 years, but the average of vehicle renew cycle is less than 4 years. It is obvious that the second-hand vehicle market has quite a few of the spaces to operate.
2.Lower price and balance the supply and demand quantity in the market
The 21st century has become "the automobile society". Cars have become an essential transportation for the modern families, but consumers from different levels have different demands for cars.
Part of the consumers, which from middle class and above mainly buy new cars. They pay more attention to the reliability of the vehicles instead of the price. Most of them would consider changing cars after four or five years when the reliability of the vehicle go down and the chance of accidental breakdown increase.
But consumers, which are below the middle class, then take the second-hand car as the main consideration. It is because of the lower price consideration. The price of second-hand car is about half of a new car. It's still quite reliable to be used for two to four years. And the loss of depreciation value would be smaller than buying a new car. Such second-hand car is still possible to be sold once more after using. The price then would be only 20%-30% of a new one. Those cars are mainly sold to the people who have lower income or students who have no income.
Moreover there are some older cars that even cost less, which costs only about 5%-10% of a new car. Although it is a must to spend certain money on maintenance costs, the total cost would still be the lowest. It is quite beneficial. Therefore the supply of second-hand vehicle is a little bit larger than the demand quantity. The price of the second-hand cars is also lower. That is to balance the supply and demand quantity in the market
3.The system organize well and promote the market to be developed
Second-hand vehicle markets in the developed countries generally form a perfect purchasing and selling system. And that promotes the organization of second-hand auction and wholesale. Governments formulate related laws of second-hand vehicle trading to protect consumer's rights and interests. Each organization runs fairly and effective and that makes the price in second-hand vehicle markets of the developed countries tend to be stable. Consumers do not have to worry about the loss which is from the unstable value of vehicles. The value of second-hand vehicles affects the guarantee value of vehicles and the stimulation of buying new cars deep and far. The steady of second-hand vehicle markets has made new- and second-hand vehicle markets promote fairly well.
The generality of second-hand vehicle markets in developing countries are:
1. Less source and higher price
Because of the average income of the developing countries is lot more lower than the developed countries, the proportion of wanting to buy second-hand cars is lot more than the developed countries. Furthermore, vehicle renew cycle of these countries is longer than the developed countries. Therefore make the source of second-hand vehicle to be limited. And the situation of supply is unable to meet the demand is very common. It has made the price of second-hand vehicle become lot higher than the developed countries. Even though, the price of second-hand cars is still lower than new cars. Considering from the economy, second-hand cars are still popular.
2. The trading is flexible and the management is tend to be ruled day by day
The main characteristic of the second-hand vehicle markets in developing countries is flexible trading. There are direct personal trading, store trading, and also auction trading. Anyhow they regulate and run by the market rules themselves.
Although the second-hand vehicles markets have go along for many years, it is still immature. There is still a certain difference in scale, price, market standard, and market operation from developed countries. These countries have already realized this and are now trying to improve. They are endeavoring to regulate the law and the policy and also coordinating with the new- and second-hand markets. They are trying to regulate the price and balance the supply and demanding. These have made their trading way become closer to the developed countries.
Market of Taiwan has also followed this tendency to Europe, America, and Japan. Comparing with the developed countries, the second-hand vehicle markets in Taiwan starts later but develops faster. The trading way is like the Eight Immortals crossing the sea, each one showing his special prowess. The trading pattern and the legal rules are still not soundness. The disputes happen quite often. Before the information of a new car has not fully exposed, it is risky to purchase second-hand car. Consumer could just be the last white mouse for the sellers and can only pray for himself.
Making a comprehensive survey of second-hand vehicle markets in developed countries like America and Japan, the policy, the law and the coordination between the new- and second-hand vehicle markets are the main reason to make second-hand vehicle markets become prosperous in these countries.
Because of the legal standard is incomplete in our country. The problem of asymmetric information exists in the market. And that makes the rights and the interests of consumers can not be protected when they purchase cars. This research is mainly investigating via interviews, related documents, and theories, and also case study and analyze. Then induces the system which can promote consumers' rights and interests and also to make consumers' rights and interests to be protected. Therefore they can feel at ease buying cars and also trying to provide proprietors a way to make reference of the system establishment.
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Planar Array Structures For Two-dimensional Direction-of-arrival EstimationFilik, Tansu 01 May 2010 (has links) (PDF)
In this thesis, two-dimensional (2-D) direction-of-arrival (DOA) estimation problem is considered. Usually, DOA estimation is considered in one dimension assuming a fixed elevation angle. While this assumption simplifies the problem, both the azimuth and elevation angles, namely, the 2-D DOA estimates are required in practical scenarios. In this thesis, planar array structures are considered for 2-D DOA estimation. In this context, V-shaped arrays are discussed and some of the important features of these arrays are outlined. A new method for the design of V-shaped arrays is presented for both isotropic and directional beam patterns. The design procedure is simple and can be applied for both uniform and nonuniform V-shaped sensor arrays. Closed form expressions are presented for the V-angle in order to obtain isotropic angle performance. While circular arrays have the isotropic characteristics, V-shaped arrays present certain advantages due to their large aperture for the same number of sensors and inter-sensor distance. The comparison of circular and V-shaped arrays is done by considering the azimuth and elevation Cramer-Rao Bounds (CRB). It is shown that V-shaped and circular arrays have similar characteristics for the sensor position errors while the uniform isotropic (UI) V-array performs better when there is mutual coupling and the sources are correlated.
In the literature, there are several techniques for 2-D DOA estimation. Usually, fast algorithms are desired for this purpose since a search in two dimensions is a costly process. These algorithms have a major problem, namely, the pairing of the azimuth-elevation couples for multiple sources. In this thesis, a new fast and effective technique for this purpose is proposed. In this technique, a virtual array output is generated such that when the ESPRIT algorithm is used, the eigenvalues of the rotational transformation matrix have the 2-D angle information in both magnitude and phase. This idea is applied in different scenarios and three methods are presented for these cases. In one case, given an arbitrary array structure, array interpolation is used to generate the appropriate virtual arrays. When the antenna mutual coupling is taken into account, a special type of array structure, such as circular, should be used in order to apply the array interpolation. In general, the array mutual coupling matrix (MCM) should have a symmetric Toeplitz form. It is shown that the 2-D DOA performance of the proposed method approaches to the CRB by using minimum number of antennas in case of mutual coupling. This method does not require the estimation of the mutual coupling coefficients. While this technique is effective, it has problems especially when the number of sources increases. In order to improve the performance, MCM is estimated in the third approach. This new approach performs better, but it cannot be used satisfactorily in case of multipath signals. In this thesis, the proposed idea for fast 2-D DOA estimation is further developed in order to solve the problem when mutual coupling and multipath signals jointly exist. In this case, real arrays with some auxiliary sensors are used to generate a structured mutual coupling matrix. It is shown that the problem can be effectively solved when the array structure has a special form. Specifically, parallel uniform linear arrays (PULA) are employed for this purpose. When auxiliary sensors are used, a symmetric banded Toeplitz MCM is obtained for the PULA. This allows the application of spatial smoothing and ESPRIT algorithm for 2-D DOA estimation. The proposed algorithm uses triplets and presents closed form paired 2-D DOA estimates in case of unknown mutual coupling and multipath signals. Several simulations are done and it is shown that the proposed array structure and the method effectively solve the problem.
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