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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.
121

Im Schwerpunkt der Anschlusspunkte – Zur Genauigkeit geodätischer Koordinatentransformationen

Lehmann, Rüdiger January 2010 (has links)
Eine in der Geoda¨sie bekannte Regel besagt, dass die Genauigkeit zu transformierender Neupunkte im Schwerpunkt der Anschlusspunkte am höchsten ist. Weniger bekannt ist, unter welchen Voraussetzungen dies generell gilt. Allgemein unbekannt ist bisher, auf welche Koordinatentransformationen man diese Regel ausdehnen kann. Wir zeigen dies auf und untersuchen einen Fall, in dem diese Regel nicht gilt. Es stellt sich heraus, dass der am genauesten transformierbare Neupunkt theoretisch sogar außerhalb der konvexen Hülle der Anschlusspunkte liegen kann. / A rule well-known in Geodesy states that the accuracy of points to be transformed is best in the centre of gravity of the control points. Less well- known is, under which conditions this rule gen- erally applies. The exact set of coordinate transforms, to which we can extend the validity of this rule, is widelyunknown. We demonstrate this and investigate a case, in which this rule does not apply. It turns out that the most accurately transformable point be even be located outside the convex hull of the control points.
122

Density Functional Theory Study of Vibrational Spectra. 4. Comparison of Experimental and Calculated Frequencies of All-Trans-1,3,5,7-Octatetraene - the End of Normal Coordinate Analysis?

Zhou, Xuefeng, Mole, Susan J., Liu, Ruifeng 01 January 1996 (has links)
Comparison of the observed and calculated vibrational frequencies of all-trans-octatetraene indicates that the density functional theory (DFT) using Becke's exchange and Lee-Yang-Parr's correlation functionals is as accurate as the Hartree-Fock (HF)-based scaled quantum mechanical force field approach in predicting fundamental vibrational frequencies. As the DFT calculation does not use any empirical parameters pertaining to the subject molecule and its computational cost scales more favorably than that of the HF theory, it is a more promising approach to molecular vibrational problems and should replace the empirical normal coordinate analysis for assisting vibrational assignments.
123

Implementation of a Hardware Coordinate Wise Descend Algorithm with Maximum Likelihood Estimator for Use in mMTC Activity Detection / En hårdvaruimplementation av en koordinatvis minimeringsalgoritm baserat på maximum liklihoodestimering för aktivitetsdetektion i mMT

Henriksson, Mikael January 2020 (has links)
In this work, a coordinate wise descent algorithm is implemented which serves the purpose of estimating active users in a base station/client wireless communication setup. The implemented algorithm utilizes the sporadic nature of users, which is believed to be the norm with 5G Massive MIMO and Internet of Things, meaning that only a subset of all users are active simultaneously at any given time. This work attempts to estimate the viability of a direct algorithm implementation to test if the performance requirements can be satisfied or if a more sophisticated implementation, such as a parallelized version, needs to be created.The result is an isomorphic ASIC implementation made in a 28 nm FD-SOI process, with proper internal word lengths extracted through simulation. Some techniques to lessen the burden on hardware without losing performance is presented which helps reduce area and increase speed of the implementation. Finally, a parallelized version of the algorithm is proposed, if one should desire to explore an implementation with higher system throughput, at almost no furtherexpense of user estimation error.
124

Étalonnage d'un espace de travail par multilatération / Calibration of a working space using multilateration

Camboulives, Martin 11 December 2015 (has links)
Les travaux présentés dans cette thèse ont pour but la maîtrise des méthodes d'étalonnage par multilatération. Ils s'inscrivent dans une collaboration entre le Laboratoire national de métrologie et d'essais (LNE) et le Laboratoire Universitaire de Recherche en Production Automatisée (LURPA). Dans ces travaux, la multilatération est dite séquentielle car réalisée avec un unique Laser Tracer positionné successivement plusieurs points de l'espace. La détermination de ces positions ainsi que des bras-morts de l'interféromètre est le point clef de la méthode. Pour l'évaluation des incertitudes, le raccordement aux étalons est fait via les longueurs interférométriques délivrées par le Laser Tracer. Elles sont associées à des défauts caractéristiques d'une cinématique particulière ou aux coordonnées des points mesurés. Elles sont évaluées au travers de la stratégie de mesure et des performances de chaque composant intervenant lors de la procédure d'étalonnage. Mesurer les coordonnées d'un point cible de l'espace par multilatération implique de connaître les positions des points de vue depuis lesquels le point est visé, ainsi que les longueurs qui le séparent des points de vue qui en pratique sont les centres des Laser Tracer. La méthode que nous proposons permet d'identifier les positions et bras-morts des Laser Tracer qui constituent un repère de mesure qualifié de Système Mesurant de Référence (SMR), puis de réaliser la multilatération. Ensuite, l'extraction de défauts volumiques permet éventuellement d'identifier les défauts cinématiques d'une chaîne de solides particulière associée au volume de mesure. Dans cette optique, nous proposons une procédure type inspirée des travaux du LNE axés sur l'utilisation d'une barre à trous pour identifier les défauts cinématiques d'une MMT à trois axes cartésiens. Cette méthode se démarque des approches actuellement proposées car le SMR est construit indépendamment de l'identification des défauts de l'appareil de mesure. De plus, la procédure d'étalonnage que nous proposons repose sur une investigation axe par axe plutôt que par une optimisation globale du problème d'étalonnage. En nous focalisant sur les machines à mesurer tridimensionnelles (MMT), nous proposons un bilan d'incertitudes qui a inclus des facteurs dont le rôle n'était auparavant pas pris en compte dans la littérature. Ces facteurs sont liés au fait de n'utiliser qu'un seul Laser Tracer pour étalonner la MMT. Nous proposons un module d'évaluation des incertitudes qui permet, grâce à des simulations de Monte Carlo, d'identifier l'influence de chacun de facteurs d'incertitude. La pertinence d'une stratégie d'étalonnage peut donc être évaluée à priori de la mise en œuvre de la procédure. L'outil de simulation proposé s'appuie sur la simulation du comportement de la MMT et de celui du Laser Tracer lors de la mesure. Deux indicateurs d'incertitude sont proposés pour l'étude des incertitudes. L'un est lié à l'exactitude de calcul du SMR construit sur les positions successives du Laser Tracer, l'autre est une image de l'incertitude obtenu sur les profils des défauts cinématiques calculés. Cet outil de simulation a permis de valider l'importance des sources d'incertitudes établies initialement pour l'étalonnage d'une MMT à trois axes cartésiens. L’ensemble de la démarche a été appliqué et validé pour une MMT à 3 axes cartésiens en conditions de laboratoire chez un industriel. Cependant, l’approche proposée découple la construction du SMR de l’identification des défauts cinématiques. Elle peut donc être facilement étendue à des systèmes de mesure 3D variés. Nous montrons donc que la démarche globale peut s’appliquer à des espaces de mesure sans cinématique machine. Il s’agit alors d’identifier les défauts volumiques associés à l’espace de mesure, ainsi que les incertitudes associées à la méthode d’étalonnage mise en œuvre. Afin d’illustrer notre propos, nous traitons le cas d’espaces de travail associés à un système de mesure optique. / This thesis aims at developing calibration procedures and methods for measuring tools such as coordinate measuring machines (CMMs) and stereovision devices. This work is incorporated within the framework of a collaboration between the Laboratoire national de métrologie et d’essais (LNE) and the Automated Production Research Laboratory (LURPA). In the scope of this thesis, multilateration is qualified as sequential because it is carried out by a single tracking interferometer (Laser Tracer) that is placed in different positions during the calibration procedure. In order to assess the calibration uncertainties, the link to the length standards is obtained through the measured lengths provided by the interferometer. Each one of these measured lengths is linked to the kinematic chain parametric errors that cause the volumetric errors of the CMM or directly to the measured points coordinates. They are assessed thanks to the study of both the calibration procedure and the performance of each component that takes part in the calibration procedure.Performing multilateration to obtain the spatial coordinates of a point requires to know both the stand points from which the point is measured and the distances between the stand points and the measured point. Practically, the stand points are the Laser Tracer positions. The proposed method aims at identifying the Laser Tracer’s positions and dead-paths lengths first in order to build a reference measuring frame, then performing multilateration. Then, if the measuring device is a CMM, its kinematic chain parametric errors are identified. For this matter, we propose a specific procedure based on the LNE knowledge on CMM calibration carried out using hole-bars. The originality of the proposed method lies in the fact that the reference measuring frame and the measuring device errors are calculated independently from each other. Plus, when addressing the case of a CMM calibration, the kinematic chain parametric errors are extracted one by one when a global optimization algorithm is usually performed nowadays.We focus on the case of CMMs calibration and we propose a precise analysis of all the sources of errors. It includes factors which influence was not studied before. They appear to result from the fact that a single tracking interferometer is used to calibrate the CMM. A simulation module based on a Monte Carlo approach has been developed. It enables the study of the influence of each source of errors independently from the other ones. Hence, the relevance of a measuring strategy can be assessed beforehand. This module simulates the behaviour of both the CMM and the Laser Tracer to evaluate uncertainties. We propose two indicators to observe the relative influence of each uncertainty factor. The first one is linked to the reference frame that is built on the successive positions of the Laser Tracer. The second one represents the global uncertainty one the kinematic chain parametric errors. This uncertainty assessment module has been successfully used to highlight the importance of sources of errors which role used to not be studied.The calibration procedure and uncertainty assessment module we propose have been successfully applied to a 3-axis cartesian CMM in laboratory conditions. Plus, since the reference measuring frame and the kinematic chain parametric errors identification are performed separately, the method we propose can be applied to other measuring devices. We especially explain how to apply it in the case of a measuring device based on stereovision.
125

A Study on Web Search based on Coordinate Relationships / 同位関係に基づくウェブ検索に関する研究

Meng, Zhao 23 September 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第20030号 / 情博第625号 / 新制||情||109(附属図書館) / 33126 / 京都大学大学院情報学研究科社会情報学専攻 / (主査)教授 田中 克己, 教授 吉川 正俊, 教授 黒橋 禎夫 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
126

Integration of eye tracking device and 3D motion capture for simultaneous gaze and body movement analysis / Integrering av ögonspårningsenhet och 3D-rörelsefångst för samtidig blick-och kroppsrörelseanalys

Narasappa, Deepa January 2022 (has links)
The purpose of this project was to analyze the coordination between gaze and the upper limb movement while performing a predefined task. We implemented a method to simultaneously compute and visualize recorded gaze data from a head mounted eye tracker and motion data from a motion capture system in the same coordinate system.  A python script was implemented to temporarily synchronize the two systems and then proceed with the spatial/coordinate transformation which was validated with the data acquired while the subject was asked to perform specific tasks. Task 1 was to fixate his gaze on a block placed in the center of a table and the Task 2 was to stack the blocks by picking it up and placing it on top of each other. Wrist and elbow flexion-extension angles were tracked simultaneously based on reflective markers trajectories while performing the task. This was visualized and discussed on how the results of our study suggest that the eye movements play a vital role in planning, estimating, coordinating and providing feedback for the body to perform a motor task.
127

Geo-Enabling Piste Maps Using Anchor Points / Platsbestämning av geografiska koordinater på pistkartor med hjälp av ankarpunkter

Pei, Lou-Lou January 2021 (has links)
Piste maps have been used as navigational aids by winter sports enthusiasts for decades. These maps are often hand drawn and are designed to be visually pleasing while still providing an overview of the terrain of a ski resort. As smartphones have become the go-to tool when satisfying our daily navigational needs, the expectations of a digital map have changed. One of these expectations is being able to position yourself and others on the map. With the existing GPS functionality of smartphones, there is a great potential for bringing classical piste maps into the digital age. This project proposes a solution which can position a user given their geographical position on a piste map. The solution includes a process for identifying anchor points which tie geographical coordinates to piste map coordinates, a suitable method of triangulating these points, combined with an algorithm that finds the most suitable triangle to use for finding the transformation parameters, and finally an affine transformation that yields the corresponding piste map coordinates for a given geographical position. The solution also proposes a method to find the smallest but sufficient set size of anchor points for a resort to create a useful and cost efficient model of transformation. The thesis work also presents possible implementations of the positioning algorithm, such as creating a smooth transition between a piste map view and a satellite map view in an Android device. This includes automatic panning and rotation of the satellite map in response to the centering of the piste map on the device screen. Geo-enabling piste maps enables many more interesting applications, such as recording and displaying skiing statistics, providing suggestions of new unexplored areas, keeping track of family or friends, selective location sharing, location-tagged weather and disaster information, and in the wake of the COVID-19 pandemic, providing a user- friendly interface for displaying localized congestion levels. / Skidåkare och andra vintersportsentusiaster har använt pistkartor som standarden för navigering i skidorter i flera decennier. Dessa kartor är ofta handritade av en konstnär, och är designade för att vara visuellt tilltalande samtidigt som de förser användaren med en abstraherad översikt av skidanläggningen. När mobiltelefonen tog över våra dagliga navigeringsbehov har också förväntningarna av en digital karta förändrats. En av dessa förväntningar är att kunna positionera sig själv och andra på kartan. Med hjälp av den nuvarande GPS teknologin som finns tillgänglig i mobiltelefoner finns ett stort potential för att vidareutveckling och digitalisering av den klassiska pistkartan. Detta projekt beskriver en digital lösning som kan positionera en användare givet deras geografiska koordinater på en pistkarta. Lösningen består av en process för att identifiera ankarpunkter som binder samman geografiska koordinater och pistkarte-koordinater, samt en metod för att triangulera dessa punkter. Detta är kombinerat med en algoritm som hittar den mest passande triangeln vars transformationsmatris kan användas för att transformera de givna geografiska koordinaterna till pistkarte-koordinater. Lösningen föreslår också en metod för att hitta det minsta tillräckliga antalet ankarpunkter som krävs för att skapa en användbar och kostnadseffektiv transformationsmodell. Examensarbetet föreslår också möjliga implementationer av positioneringslösningen, som att skapa en sammanhängande transition mellan pistkarta och satellit-vy i en Android app. Detta innefattar automatiska förflyttningar och rotationer av satellit-kartan beroende på hur pistkartan är positionerad i relation till skärmens centrum. Positioneringsalgoritmen möjliggör flera andra intressanta tillämpningar, som att visualisera inspelade åk-statistik, ge förslag på tidigare outforskade backar och skidområden, visa upp var vänner och familj befinner sig, selektiv platsdelning, platsrelaterad väder- och snödata, samt förutsättningar för att skapa en användarvänlig visualisering av områdesspecifika trängselnivåer.
128

Use of Web-Based Technology to Enhance Instruction of Virginia's Seventh and Eighth Grade Geometry Standards of Learning.

Fields, Lisa Ann 05 May 2007 (has links) (PDF)
The purpose of this thesis is to develop web-based modules for enhancing instruction of the geometry sections of the Virginia Standards of Learning in the seventh and eighth grades. While all of Virginia's seventh and eighth grade Standards of Learning strands are certainly worthy of these types of modules, geometry appeals to me most because of the vast amount of web-based resources that will be valuable when organized into modules. It is my hope that teachers of these grades will find this useful in their instruction of geometry.
129

Sparse Ridge Fusion For Linear Regression

Mahmood, Nozad 01 January 2013 (has links)
For a linear regression, the traditional technique deals with a case where the number of observations n more than the number of predictor variables p (n > p). In the case n < p, the classical method fails to estimate the coefficients. A solution of the problem is the case of correlated predictors is provided in this thesis. A new regularization and variable selection is proposed under the name of Sparse Ridge Fusion (SRF). In the case of highly correlated predictor, the simulated examples and a real data show that the SRF always outperforms the lasso, eleastic net, and the S-Lasso, and the results show that the SRF selects more predictor variables than the sample size n while the maximum selected variables by lasso is n size.
130

Towards A Self-calibrating Video Camera Network For Content Analysis And Forensics

Junejo, Imran 01 January 2007 (has links)
Due to growing security concerns, video surveillance and monitoring has received an immense attention from both federal agencies and private firms. The main concern is that a single camera, even if allowed to rotate or translate, is not sufficient to cover a large area for video surveillance. A more general solution with wide range of applications is to allow the deployed cameras to have a non-overlapping field of view (FoV) and to, if possible, allow these cameras to move freely in 3D space. This thesis addresses the issue of how cameras in such a network can be calibrated and how the network as a whole can be calibrated, such that each camera as a unit in the network is aware of its orientation with respect to all the other cameras in the network. Different types of cameras might be present in a multiple camera network and novel techniques are presented for efficient calibration of these cameras. Specifically: (i) For a stationary camera, we derive new constraints on the Image of the Absolute Conic (IAC). These new constraints are shown to be intrinsic to IAC; (ii) For a scene where object shadows are cast on a ground plane, we track the shadows on the ground plane cast by at least two unknown stationary points, and utilize the tracked shadow positions to compute the horizon line and hence compute the camera intrinsic and extrinsic parameters; (iii) A novel solution to a scenario where a camera is observing pedestrians is presented. The uniqueness of formulation lies in recognizing two harmonic homologies present in the geometry obtained by observing pedestrians; (iv) For a freely moving camera, a novel practical method is proposed for its self-calibration which even allows it to change its internal parameters by zooming; and (v) due to the increased application of the pan-tilt-zoom (PTZ) cameras, a technique is presented that uses only two images to estimate five camera parameters. For an automatically configurable multi-camera network, having non-overlapping field of view and possibly containing moving cameras, a practical framework is proposed that determines the geometry of such a dynamic camera network. It is shown that only one automatically computed vanishing point and a line lying on any plane orthogonal to the vertical direction is sufficient to infer the geometry of a dynamic network. Our method generalizes previous work which considers restricted camera motions. Using minimal assumptions, we are able to successfully demonstrate promising results on synthetic as well as on real data. Applications to path modeling, GPS coordinate estimation, and configuring mixed-reality environment are explored.

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