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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.
11

Radionuklidų savitojo aktyvumo statybinėse medžiagose Lietuvoje eksperimentinis tyrimas, jų sukeltos apšvitos modeliavimas ir vertinimas / Investigation of concentrations of radionuclides in Lithuanian construction materials, modelling and evaluation of exposure due to these radionuclides

Pilkytė, Laima 10 November 2006 (has links)
The study is devoted to problems of exposure caused by radionuclides in construction materials. Results received by gamma measurements and calculations (dose modeling) are used. Construction materials produced and/or used in Lithuania were investigated. The results of measurements (concentrations of natural radionuclides and activity indexes) are given for different types of construction materials. On the basis of these results and peculiarities of use of construction materials they have been classified according to their radiological significance. It helps to determine possible amounts of construction materials to be investigated and priorities of investigations. Relationship between activity indexes of different construction materials and dose rates in premises constructed of these construction materials has been determined. It might be used for increase of precision of personal dosimetric measurements performed in premises constructed of different materials. Possible relationship between absorbed dose rate indoors and concentration of indoor radon is discussed. Results of measurements of concentrations of natural radionuclides in archeological samples of construction materials are also presented and discussed. Dose modeling has been performed with the help of ALARA planning tool Visiplan 3D. Distributions of absorbed dose rate in standard living premises have been determined, relationship between dose rate and different parameters of constructions, such as thickness... [to full text]
12

Indoor location estimation using a wearable camera with application to the monitoring of persons at home / Localisation à partir de caméra vidéo portée

Dovgalecs, Vladislavs 05 December 2011 (has links)
L’indexation par le contenu de lifelogs issus de capteurs portées a émergé comme un enjeu à forte valeur ajoutée permettant l’exploitation de ces nouveaux types de donnés. Rendu plus accessible par la récente disponibilité de dispositifs miniaturisés d’enregistrement, les besoins pour l’extraction automatique d’informations pertinents générées par autres applications, la localisation en environnement intérieur est un problème difficile à l’analyse de telles données.Beaucoup des solutions existantes pour la localisation fonctionnent insuffisamment bien ou nécessitent une intervention important à l’intérieur de bâtiment. Dans cette thèse, nous abordons le problème de la localisation topologique à partir de séquences vidéo issues d’une camera portée en utilisant une approche purement visuelle. Ce travail complète d’extraction des descripteurs visuels de bas niveaux jusqu’à l’estimation finale de la localisation à l’aide d’algorithmes automatiques.Dans ce cadre, les contributions principales de ce travail ont été faites pour l’exploitation efficace des informations apportées par descripteurs visuels multiples, par les images non étiquetées et par la continuité temporelle de la vidéo. Ainsi, la fusion précoce et la fusion tardive des données visuelles ont été examinées et l’avantage apporté par la complémentarité des descripteurs visuels a été mis en évidence sur le problème de la localisation. En raison de difficulté à obtenir des données étiquetées en quantités suffisantes, l’ensemble des données a été exploité ; d’une part les approches de réduction de dimensionnalité non-linéaire ont été appliquées, afin d’améliorer la taille des données à traiter et la complexité associée ; d’autre part des approches semi-supervisés ont été étudiées pour utiliser l’information supplémentaire apportée par les images non étiquetées lors de la classification. Ces éléments ont été analysé séparément et on été mis en œuvre ensemble sous la forme d’une nouvelle méthode par co-apprentissage temporelle. Finalement nous avons également exploré la question de l’invariance des descripteurs, en proposant l’utilisation d’un apprentissage invariant à la transformation spatiale, comme un autre réponse possible un manque de données annotées et à la variabilité visuelle.Ces méthodes ont été évaluées sur des séquences vidéo en environnement contrôlé accessibles publiquement pour évaluer le gain spécifique de chaque contribution. Ce travail a également été appliqué dans le cadre du projet IMMED, qui concerne l’observation et l’indexation d’activités de la vie quotidienne dans un objectif d’aide au diagnostic médical, à l’aide d’une caméra vidéo portée. Nous avons ainsi pu mettre en œuvre le dispositif d’acquisition vidéo portée, et montrer le potentiel de notre approche pour l’estimation de la localisation topologique sur un corpus présentant des conditions difficiles représentatives des données réelles. / Visual lifelog indexing by content has emerged as a high reward application. Enabled by the recent availability of miniaturized recording devices, the demand for automatic extraction of relevant information from wearable sensors generated content has grown. Among many other applications, indoor localization is one challenging problem to be addressed.Many standard solutions perform unreliably in indoors conditions or require significant intervention. In this thesis we address from the perspective of wearable video camera sensors using an image-based approach. The key contribution of this work is the development and the study of a location estimation system composed of diverse modules, which perform tasks ranging from low-level visual information extraction to final topological location estimation with the aid of automatic indexing algorithms. Within this framework, important contributions have been made by efficiently leveraging information brought by multiple visual features, unlabeled image data and the temporal continuity of the video.Early and late data fusion were considered, and shown to take advantage of the complementarities of multiple visual features describing the images. Due to the difficulty in obtaining annotated data in our context, semi-supervised approaches were investigated, to use unlabeled data as additional source of information, both for non-linear data-adaptive dimensionality reduction, and for improving classification. Herein we have developed a time-aware co-training approach that combines late data-fusion with the semi-supervised exploitation of both unlabeled data and time information. Finally, we have proposed to apply transformation invariant learning to adapt non-invariant descriptors to our localization framework.The methods have been tested on controlled publically available datasets to evaluate the gain of each contribution. This work has also been applied to the IMMED project, dealing with activity recognition and monitoring of the daily living using a wearable camera. In this context, the developed framework has been used to estimate localization on the real world IMMED project video corpus, which showed the potential of the approaches in such challenging conditions.
13

3D obstacle avoidance for drones using a realistic sensor setup / Hinderundvikande i 3D för drönare med en realistisk sensoruppsättning

Stefansson, Thor January 2018 (has links)
Obstacle avoidance is a well researched area, however most of the works only consider a 2D environment. Drones can move in three dimensions. It is therefore of interest to develop a system that ensures safe flight in these three dimensions. Obstacle avoidance is of highest importance for drones if they are intended to work autonomously and around humans, since drones are often fragile and have fast moving propellers that can hurt humans. This project is based on the obstacle restriction algorithm in 3D, and uses OctoMap to conveniently use the sensor data from multiple sensors simultaneously and to deal with their limited field of view. The results show that the system is able to avoid obstacles in 3D. / Hinderundvikande är ett utforskat område, dock för det mesta har forskningen fokuserat på 2D-miljöer. Eftersom drönare kan röra sig i tre dimensioner är det intressant att utveckla ett system som garanterar säker rörelse i 3D. Hinderundvikande är viktigt för drönare om de ska arbeta autonomt runt människor, eftersom drönare ofta är ömtåliga och har snabba propellrar som kan skada människor. Det här projektet är baserat på Hinderrestriktionsmetoden (ORM), och använder OctoMap för att använda information från många sensorer samtidigt och för att hantera deras begränsade synfält. Resultatet visar att systemet kan undvika hinder i 3D.
14

Analýza ekonomického rizika výstavbového projektu / Analysis of Economic Risk of the Construction Project

Bokorová, Martina January 2013 (has links)
This thesis deals with the risk analysis and risk management of a construction project, their detailed characteristics and classification. In the practical part, knowledge and findings from the theoretical part are applied to a project aimed at the reconstruction and completion of an indoors swimming pool in the town Kuřim. In the course of the risk analysis assessment, important information on the project were given, furthermore, risks were identified, the intensity of their impact and likelihood of their development was established, and measures to reduce the risks were recommended.
15

Undersökning av TRP tak med PIR isolering utan plastfolie / Investigation of TRP-roof construction with PIR insulation without plastic film

Pourfeiz, Hani, Karmanji, Yadgar January 2015 (has links)
Idag ligger fokus på energieffektivisering av byggnader. I och med detta ligger tung vikt på fuktsäkerhetsprojektering i konstruktioner som i sin tur måste vara lufttäta och diffusionstäta. Kombinationen av svenska vinterperioder och övertrycket som uppstår inomhus medför att taken utsätts för stora påfrestningar. Luften inomhus innehåller alltid mer fukt än luften utomhus. Då fukt alltid strävar efter att jämna ut sig går den varma och fuktiga inomhusluften till utrymmen med lägre fukthalt eller lägre lufttryck. Det är bland annat av dessa anledningar man använder ångspärr i ytterväggar och takkonstruktioner. Syftet med detta projekt är att genomföra en fuktteknisk bedömning för takkonstruktioner uppbyggda av TRP plåt, PIR isolering utan plastfolie. Anledningen till att bygga tak utan plastfolie är att sätta fuktfrågorna i fokus vid nybyggnadsprojekt samt att eftersträva skapandet av fuktsäkra och sunda konstruktioner. För att analysera takkonstruktionen samt genomföra fukttekniska bedömningar har simuleringar av konstruktionen under olika förutsättningar i WUFI Pro 5.1. genomförts. Därefter har resultatet analyserats ur diffusions- och konvektionssynpunkt. Resultaten visar inga större skillnader ur diffusionssynpunkt. Dock är skillnaderna mer uppenbara ur konvektionssynpunkt. Fuktmängden i konstruktionen utan plastfolie var betydligt större än konstruktion med plastfolie. Resultaten visar på att luftläckaget och fuktmängden har ett proportionellt förhållande med luftspaltbredden som bildas mellan PIR isoleringselementen. Detta gäller om ingen plastfolie används i konstruktionen. Slutsatsen är att det råder en större risk för luftläckage hos takkonstruktionen utan plastfolie på grund av otätheter i skarvar och spalter. För att få en fuktsäker och sund konstruktion rekommenderar författarna att plastfolie används. / Nowadays there is a high focus on energy efficiency of buildings. Therefore, a lot of resources are dedicated to moisture management in order to ensure that constructions stay airproof and diffused.  The combination of Swedish winter periods and the overpressure that occurs indoors means that the ceilings are subjected to the great stress. Indoor air contains more moisture than the air outdoors. As moisture is always striving to even out, the hot and humid indoor air moves to spaces with lower moisture content or lower air pressure. It is partly for these reasons why it is necessary to use a vapor barrier in the outer wall and roof construction. The purpose of building roofs without plastic foil is to put moisture issues in focus for new construction projects, but also, seek to create moisture proof and healthy construction designs. Further the goal of this project is to conduct a moisture technical assessment of roof structures built by TRP plate and PIR insulation without plastic film. Additionally, investigate if PIR-insulation can act as diffusion and convection protection. In order to analyze the roof structure and conduct moisture technical assessments, the design has been simulated using WUFI Pro 5.1 during different conditions. The result has then been analyzed from diffusion and convection perspectives. The results showed no major differences when compared from diffusion point of view. However, the differences are more obvious from convection perspective. The amount of moisture in the construction without plastic foil was considerably larger than the construction with a plastic foil. The results also showed that the air leakage and moisture amount has proportional ratio to the air gap width between the PIR-insulation elements. This is the case if no plastic foil used in the construction. The conclusion is that there is a greater risk of air leakage in the roof construction without the plastic foil because of leaks in the joins or gaps. For a moisture-proof and healthy design, the authors recommend that a plastic foil should be used.
16

Responsive Textile Geometries : Vanadisbadet Revised

Aidas, Nina January 2011 (has links)
How can principles found in textile behaviour be translated into architectural expression? With water as a program in context of a new bath in Vanadislunden, Stockholm, this project studies how a rigid material can be percieved as soft and flexible.

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