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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Advanced scanning magnetoresistive microscopy as a multifunctional magnetic characterization method / Weiterentwickelte Rastermagnetowiderstandsmikroskopie als multifunktionale magnetische Charakterisierungsmethode

Mitin, Dmitriy 18 May 2017 (has links) (PDF)
Advanced scanning magnetoresistive microscopy (SMRM) — a robust magnetic imaging and probing technique — is presented. It utilizes conventional recording heads of a hard disk drive as sensors. The spatial resolution of modern tunneling magnetoresistive sensors is nowadays comparable with more commonly used magnetic force microscopes. Important advantages of SMRM are the ability to detect pure magnetic signals directly proportional to the out-of-plane magnetic stray field, negligible sensor stray fields, and the ability to apply local bipolar magnetic field pulses up to 10 kOe with bandwidths from DC up to 1 GHz. The performance assessment of this method and corresponding best practices are discussed in the first section of this work. An application example of SMRM, the study on chemically ordered L10 FePt is presented in a second section. A constructed heater unit of SMRM opens the path to investigate temperature-dependent magnetic properties of the medium by recording and imaging at elevated temperatures. L10 FePt is one of the most promising materials to reach limits in storage density of future magnetic recording devices based on heat-assisted magnetic recording (HAMR). In order to be implemented in an actual recording scheme, the medium Curie temperature should be lowered. This will reduce the power requirements, and hence, wear and tear on a heat source — integrated plasmonic antenna. It is expected that the exchange coupling of FePt to thin Fe layers provides high saturation magnetization and elevated Curie temperature of the composite. The addition of Cu allows adjusting the magnetic properties such as perpendicular magnetic anisotropy, coercivity, saturation magnetization, and Curie temperature. This should lead to a lowering of the switching field of the hard magnetic FeCuPt layer and a reduction of thermally induced recording errors. In this regard, the influence of the Fe layer thickness on the switching behavior of the hard layer was investigated, revealing a strong reduction for Fe layer thicknesses larger than the exchange length of Fe. The recording performance of single-layer and bilayer structures was studied by SMRM roll-off curves and histogram methods at temperatures up to 180 °C In the last section of this work, SMRM advantages are demonstrated by various experiments on a two-dimensional magnetic vortex lattice. Magnetic vortex is a peculiar complex magnetization configuration which typically appears in a soft magnetic structured materials. It consists of two coupled sub-systems: the core, where magnetization vector points perpendicular to the structure plane, and the curling magnetization where magnetic flux is rotating in-plane. The unique properties of a magnetic vortex making it an object of a great research and technological interest for spintronic applications in sensorics or data storage. Manipulation of the vortex core as well as the rotation sense by applying a local field pulse is shown. A spatially resolved switching map reveals a significant "write window" where vortex cores can be addressed correctly. Moreover, the external in-plane magnet extension unit allow analyzing the magnetic vortex rotational sense which is extremely practical for magnetic coupling investigations of magnetic coupling phenomena.
92

Proposta de linguagem geradora de imagens em impressoras de página / A page description language for raster non impact printers.

Stefani, Mario Antonio 16 August 1990 (has links)
Uma compacta linguagem descritora de páginas, destinada a impressoras não-impacto de estrutura raster é apresentada. Tal linguagem foi implementada usando o processador gráfico TMS4010, da Texas Instruments e possui uma estrutura muito similar à encontrada nas linguagens interpretativas encadeadas. A linguagem é totalmente modular e interativa, e se utiliza um modelo gráfico simples, visando simular as tarefas normalmente encontradas nas artes tipográficas. São efetuadas comparações com outras linguagens comerciais, visando avaliar suas possibilidades. Uma pequena introdução à tecnologia das impressoras laser é apresentada. / A small Page description language intended for raster non-impact printers is presented. The language is implemented using the Texas Instruments TMS4010 Graphics system processor and its structure is similar that encountered in threaded interpretative languages. The language is fully modular and interactive, and uses a simple graphic model to simulate the same common tasks encoutered in typographical arts. Comparison are made with other comercial languages to perform some evaluations on its possibilities. A small introduction on the laser printer technology is presented.
93

Modelling the Cross-Country Trafficability with Geographical Information Systems

Gumos, Aleksander Karol January 2005 (has links)
<p>The main objectives of this work were to investigate Geographical Information Systems techniques for modelling a cross-country trafficability. To accomplished stated tasks, reciprocal relationships between the soil deposits, local hydrology, geology and geomorphology were studied in relation to the study area in South-Eastern Sweden.</p><p>Growing awareness of nowadays users of GIS in general is being concentrated on understanding an importance of soil conditions changed after cross-country trafficability. Therefore, in this thesis, constructing of the Soil Knowledge Database introduced to the genuine geological soil textural classes a new, modified geotechnical division with desirable for off-road ground reasoning measurable factors, like soil permeability, capillarity or Atterberg’s consistency limits.</p><p>Digital Elevation Model, the driving force for landscape studies in the thesis, was carefully examined together with the complementary datasets of the investigated area. Testing of the elevation data was done in association to the hydrological modelling, which resulted with the Wetness Index map. The three distinguishable soil wetness conditions: dry, moist and wet, were obtained, and used consequently for creation of the static ground conditions map, a visible medium of soils susceptibility to for example machine compaction.</p><p>The work resulted with a conceptual scheme for cross-country trafficability modelling, which was put into effect while modeling in GIS. As a final outcome, by combining all processed data together, derivatives were incorporated and draped over the rendered 3D animating scene. A visually aided simulation enabled to concretized theoretical, hypothetical and experimental outcomes into one coherent model of apprised under Multicriterial Evaluation techniques standardized factor maps for ground vehicle maneuverability. Also further steps of research were proposed.</p>
94

Modelling the Cross-Country Trafficability with Geographical Information Systems

Gumos, Aleksander Karol January 2005 (has links)
The main objectives of this work were to investigate Geographical Information Systems techniques for modelling a cross-country trafficability. To accomplished stated tasks, reciprocal relationships between the soil deposits, local hydrology, geology and geomorphology were studied in relation to the study area in South-Eastern Sweden. Growing awareness of nowadays users of GIS in general is being concentrated on understanding an importance of soil conditions changed after cross-country trafficability. Therefore, in this thesis, constructing of the Soil Knowledge Database introduced to the genuine geological soil textural classes a new, modified geotechnical division with desirable for off-road ground reasoning measurable factors, like soil permeability, capillarity or Atterberg’s consistency limits. Digital Elevation Model, the driving force for landscape studies in the thesis, was carefully examined together with the complementary datasets of the investigated area. Testing of the elevation data was done in association to the hydrological modelling, which resulted with the Wetness Index map. The three distinguishable soil wetness conditions: dry, moist and wet, were obtained, and used consequently for creation of the static ground conditions map, a visible medium of soils susceptibility to for example machine compaction. The work resulted with a conceptual scheme for cross-country trafficability modelling, which was put into effect while modeling in GIS. As a final outcome, by combining all processed data together, derivatives were incorporated and draped over the rendered 3D animating scene. A visually aided simulation enabled to concretized theoretical, hypothetical and experimental outcomes into one coherent model of apprised under Multicriterial Evaluation techniques standardized factor maps for ground vehicle maneuverability. Also further steps of research were proposed.
95

Elektrochemische Metallabscheidung mit Kapillarsonden

Müller, Anne-Dorothea 21 February 2002 (has links)
Es wird ein Verfahren zur lokalisierten elektrochemischen Abscheidung metallischer Strukturen aus Kapillarsonden vorgestellt. Der experimentelle Aufbau, die Herstellung der Sonden, das Arbeiten im Nahfeld der Probe (Scherkraft-Abstandsdetektion)sowie die verschiedenen Beschaltungmöglichkeiten der elektrochemischen Zelle werden ausführlich beschrieben. Ergänzend zu den experimentellen Arbeiten werden einerseits numerische Simulationen gezeigt, die zur Veranschaulichung der Potentialverteilung in der Apexregion dienen und qualitativ beschreiben, wie sich das Schichtdickenprofil der abgeschiedenen Strukturen mit den einstellbaren Parametern (Elektrodenpotentiale, Spitze-Probe-Abstand) variieren läßt. Andererseits werden die verschiedenen Beschaltungsmöglichkeiten der Zelle anhand von Schaltungssimulationen verglichen und so die Wahl des günstigsten Arbeitspunktes für die in den Experimenten verwendete (bi)-potentiostatische Abscheidung diskutiert. Mit dieser Anordnung wurden lokalisiert Cluster in einer porösen Aluminiumoxidmembran deponiert und anschließend abgebildet. In weiteren Strukturierungsversuchen wurden Kupfer bzw. Gold lokalisiert elektrochemisch auf ITO abgeschieden, wobei das Schichtwachstum simultan optisch in Transmission beobachtet wurde. Es werden u.a. Strukturen erzeugt, deren laterale Abmessungen kleiner als der Kapillardurchmesser sind (Fokussierung, max. Verhältnis 8:1). Die derzeit kleinsten elektrochemisch erzeugbaren Strukturen haben eine laterale Ausdehnung von ca. 5 Mikrometern. / A method for the localized electrochemical deposition of metal structures using capillary tips is presented. The experimental set-up, the tip preparation, the distance detection in near-field operation (shear-force detection), as well as the different types of circuiting of the electrochemical cell are described in detail. In addition to the experimental work, numerical simulations for the qualitative visualization of the potential distribution around the apex region show, how the films thickness profile can be adjusted with the variable parameters (electrode voltages, tip-sample distance). Circuit simulations of the electrochemical cell allow to pre-estimate the optimum working conditions for the used (bi)-potentiostatic electrode set-up. With this method, clusters have been deposited in a thin film of porous alumin oxide and imaged in shear-force mode. Gold and copper structures have been deposited on ITO, while the film growth was observed optically. The lateral dimension of the deposited structures can be smaller than the inner diameter of the capillaries (maximum focus: 8:1). The smallest structures produced in this work have lateral dimensions of 5 micrometers.
96

Modeling framework for socioeconomic analysis of managed lanes

Khoeini, Sara 08 June 2015 (has links)
Managed lanes are a form of congestion pricing that use occupancy and toll payment requirements to utilize capacity more efficiently. How socio-spatial characteristics impact users’ travel behavior toward managed lanes is the main research question of this study. This research is a case study of the conversion of a High Occupancy Vehicle (HOV) lane to a High Occupancy Toll (HOT) lane, implemented in Atlanta I-85 on 2011. To minimize the cost and maximize the size of the collected data, an innovative and cost-effective modeling framework for socioeconomic analysis of managed lanes has been developed. Instead of surveys, this research is based on the observation of one and a half million license plates, matched to household locations, collected over a two-year study period. Purchased marketing data, which include detailed household socioeconomic characteristics, supplemented the household corridor usage information derived from license plate observations. Generalized linear models have been used to link users’ travel behavior to socioeconomic attributes. Furthermore, GIS raster analysis methods have been utilized to visualize and quantify the impact of the HOV-to-HOT conversion on the corridor commutershed. At the local level, this study conducted a comprehensive socio-spatial analysis of the Atlanta I-85 HOV to HOT conversion. At the general scale, this study enhances managed lanes’ travel demand models with respect to users’ characteristics and introduces a comprehensive modeling framework for the socioeconomic analysis of managed lanes. The methods developed through this research will inform future Traffic and Revenue Studies and help to better predict the socio-spatial characteristics of the target market.
97

Defining GeoDesign and the emergent role of the sustainable sites initiative (SITES) for integrative project management

Risinger, Emily Diane 16 March 2015 (has links)
This report is a discussion of the multifarious applications of the modern day geographic information system and how the universal merit of the technology across disciplines has led to the emergence of GeoDesign. The purpose of this Master’s Professional Report was to retrace the core conceptual framework and landmark events occurring in the evolution GIS technology, and how these factors have led to recent creation of new performance based rating systems and evidence-based design techniques. The Sustainable Sites Initiative (SITES), a new performance based rating system that has emerged in response to the call for increased knowledge and best practices lacking in LEED, is discussed; along with integrated project management. This professional report was intended to be an exploratory discussion of the larger theoretical implications fueling the shift towards mandating greater standards for sustainable design. It offers some ideas for how we should continue evolving GeoDesign moving into the next century; and outlines the importance of all new rating systems needing to acknowledge the growing importance of GeoDesign and ever advancing imagery technologies in understanding complex system processes in the future. / text
98

Rašalinio spausdintuvo spalvų gamos tyrimas / Investigation of colour gamut of ink – jet printer

Šperbelis, Gediminas 21 June 2005 (has links)
It was investigated the colour reproduction on prints made in ink-jet printer. Experimentally investigated gradation characteristics of CMYK colours. It was made a 26 step strip with raster dots from 0 to 100 %. Prints were made at different printing regimes on papers with different whiteness. Zone optical densities were measured, compared with theoretical density values and gradational distortions were determined. Also were measured 100% raster strips in CIE L*a*b* coordinate system and defined the maximum reproduction of colours in ink-jet printer.
99

Zur Erzeugung hochauflösender datenschutzkonformer Mischrasterkarten

Dießelmann, Markus, Meinel, Gotthard 10 February 2015 (has links) (PDF)
Die zunehmende Verfügbarkeit adressbezogener Daten im Zusammenhang mit der Nutzung geometrischer Raster zur Raumuntergliederung haben die Voraussetzungen für kleinräumige Analysen deutlich verbessert. Bei der Verwendung personenbezogener Daten müssen datenschutzrechtliche Vorgaben eingehalten werden, falls die Rasterzellen zu wenig Fallzahlen enthalten. Vielfach werden diese Rasterzellen ausgeblendet, wodurch Informationen in der Karte verloren gehen. Eine datenschutzkonforme Alternative stellt die Aggregation von Rasterzellen dar, bis die Fallzahlen einen vorgegebenen Grenzwert überschreiten. In diesem Beitrag werden Möglichkeiten vorgestellt und bewertet, nach denen sich datenschutzkonforme Mischrasterkarten erzeugen lassen. Besonderes Augenmerk wird auf die Auflösungsverluste der erzeugten Mischrasterkarten gelegt, um geeignete Datengrundlagen für kleinräumige Analysen zu schaffen.
100

TOWARDS THE AUTOMATIC CREATION OF VECTORISED MAPS FOR URBAN AREAS FROM MEDIUM RESOLUTION AIRBORNE LASER SCAN DATA

Clode, Simon Paul Unknown Date (has links)
This dissertation addresses the problem of automated vector extraction from Airborne Laser Scanner (ALS) data in urban areas. The recent popularity of Geographic Information Systems (GIS) has stimulated research on automated object extraction in order to simplify the data acquisition and update process. By automatically generating GIS inputs and updates from a single data source, the cost of data acquisition and processing will be kept to a minimum. Compared with other remote sensing techniques, extraction of objects from ALS data is in its infancy. ALS sensor technology has evolved rapidly and now allows the acquisition of very dense point clouds in a short period of time. ALS data is unique in that it explicitly contains 3D information and is acquired from an active sensor. As such, there are several benefits that can be immediately realised by using an ALS only data approach; data acquisition will not be limited to daylight hours as with other sensors and accurate height information is contained in the data. This means that registration of different data sources is not required and as only one data source is used, acquisition costs are minimised. Apart from these facts, ALS data has some other unique properties that have not been utilised to their full potential. An ALS sensor can record both height and intensity information from multiple returns in a single swath. To date, all the available information has rarely been used. For example, the intensity of a laser return has regularly been dismissed as it was considered under-sampled and noisy. This data still contains usable information and until this information is used, the optimum object recognition results will not be achieved; thus the use of as much of this information as possible is a major focus of this thesis. As ALS is an explicit 3D data source, the early stages of development were primarily focused on topographic mapping of terrain in forested areas in order to generate Digital Terrain Models (DTMs). As sensor technology has improved, so has the achievable resolution of point clouds from ALS data, and methods to extract objects from stand-alone ALS data have emerged. Attempts have been made to create city models and maps from ALS data that included buildings, roads, trees and powerlines. Each of these spatial object types has unique attributes, which means that automatic map creation is not an easy task. For example, buildings in general are easily detected in ALS data but the building outline is not easily delineated. Another difficulty with building detection is the separation of buildings and bridges as they have many of the same properties as observed by an ALS system. Bridges can usually be found in a road network but road extraction techniques typically produce poor detection rates and often require existing data and / or user interaction in semi-automatic techniques. These simple examples highlight the complexity of automatically generating vectorised maps from ALS data or in fact any data source. In this thesis, new methods are presented for the automatic creation of vectorised maps from ALS data. A two-step processing paradigm is adopted for this purpose, namely the classification of the ALS data and the vectorisation of the classification results. A classification strategy is introduced that creates a hierarchy for object detection with respect to the ALS data itself. This approach develops an ontology between the spatial object classes and the ALS data. The hierarchical framework highlights the fact that one object might not be discernable within the data without considering another. New classification algorithms are then presented within this framework. Each algorithm attempts to exploit the attributes of the data that are consistent within the spatial object class being considered as described by the classification framework. New algorithms for the classification of roads, trees and powerlines are all introduced whilst an extension to existing building classification methods is presented. Once classification is complete, a vectorisation process specific to the task at hand can be employed to yield vectorised results. These developed vectorisation processes are new and include an algorithm that has been generalised to allow the vectorisation of thick lines in images by detecting the centreline, direction and width. The primary goal of this thesis is to present a framework of new algorithms that will allow automatic spatial object detection and vectorisation whilst providing results of an acceptable quality. The algorithms presented rely solely on ALS data and require minimal operator knowledge. Each algorithm has been designed to exploit the way in which the object exhibits itself in the data. The new algorithms are integrated into a software package called JTD (Join The Dots) that will facilitate the effective automatic processing of ALS data. The results of the new algorithms have been evaluated over four 2 x 2 km areas that have been sampled with medium resolution ALS data. The results for each area are displayed and analysed to show the applicability of the whole process in an exemplary way.

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