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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.
21

Modelování technologických kroků kontaktování čipu mikrodrátkem / Modeling of wirebonding technological steps for chip connection

Houserek, Jiří January 2013 (has links)
This work deals with a theoretical analysis of contacting semiconductor chips using wire-bonding method. There are mentioned basic types of chips packages and their contacts. In the thesis is also described software Ansys. The number of the mechanical stress and deformation simulation within micro-wire during thermocompress process were made.
22

Anotace obrazu a videa formou hry / Image and Video Annotation as a Game

Skowronek, Ondej January 2014 (has links)
This master thesis is oriented on a problem of creating video and image annotations. This problem is solved by crowdsourcing approach. Crowdsourcing games were designed and implemented to make solution of this problem . It was proven by testing that these games are capable of creating high quality annotations. Launching these games on a larger scale could create large database of annotated videos and images.
23

Improving Sinkhole Mapping Using LiDAR Data and Locating Sinkhole Hotspots in Johnson City, TN

Fasesin, Kingsley 01 December 2018 (has links)
Predicting infrastructure damage and economic impact of sinkholes requires high accuracy mapping distribution and development. The study mapped sinkholes and sinkhole hotpsots in Johnson City, TN using LiDAR-derived Digital Elevation Model (DEM) and a database of known sinkholes which were matched to LiDAR-derived depressions. For all matched depressions (n = 404), three metrics were calculated: circularity index, ratio of length to width of the Minimum Bounding Rectangle (MBR) and percent coverage of the MBR by the depression, and 3,634 new sinkholes were identified. Newly developed hotspots were identified in north Johnson City and other areas in the south near the Johnson City Medical Center. The methodology developed can be applied to identify hotspots in other small metropolitan cities and the hotspot map produced can be employed in hazard mitigation planning, resource allocation, and made available publicly to property owners and insurance companies.
24

Development of Autonomous Bounding Box Algorithms for OPIC’s Data Prioritization on the Comet Interceptor Mission

Brune, Eric January 2022 (has links)
The joint European Space Agency and Japan Aerospace Exploration Agency mission Comet Interceptor seeks to perform a flyby of a Small Solar System Body (SSSB), through use of a multi-element spacecraft. It comprises a primary spacecraft and two subspacecraft, the latter of which will encounter the intercepted object at a small enough distance that its end-of-life might occur at an impact of either the object itself or its potential coma. The Optical Periscopic Imager for Comets (OPIC) is an instrument implemented on one of these small probes which will generate monochromatic images during the encounter. Given a limited data budget before the possible impact, there is a need for data prioritization to ensure that only the most scientifically relevant data is collected. To enable this, algorithms for autonomously cropping an object nucleus from an image were developed during this thesis work. As the computational capabilities of OPIC are limited, the algorithms were required to be of low computational complexity. Additionally, given that the close environment of SSSB in general and comets in particular often exhibit considerable quantities of gas and dust which can generate cluttering in images, the algorithms developed were required to be resistant to noise. Three image cropping algorithms were developed with varying computational complexities. These were tested for cropping accuracy and relative execution times on data from both previous space missions as well as simulated photorealistic images. All three algorithms were able to properly find a bounding box of an object nucleus and any of its significant plumes. The accuracy in cropping correctness of the region borders generated increased with the computational complexity of the algorithms.
25

Modeling and Control of a Planar Bounding Quadrupedal Robot

Ward, Patrick John 01 June 2022 (has links) (PDF)
Legged robots have the potential to be a valuable technology that provides agile and adaptive locomotion over complex terrain. To realize legged locomotion's full abilities a control design must consider the nonlinear piecewise dynamics of the systems. This paper aims to develop a controller for the planar bounding of a quadrupedal robot. The bounding of the quadruped robot is characterized by a simplified hybrid model that consists of two subsystems for stance and flight phases and the switching laws between the two states. An additional model, the Multibody model, with fewer simplifications, is used concurrently to best approximate real-world behavior. The bounding gait (periodic orbit) of the robot is predicted by an optimization method based on the numerical integration of the differential equations of subsystems. To stabilize the gait, a switching controller is applied which can be split into two separate phases: stance-phase and swing-phase control. The stance phase implements reaction force control utilizing a body state feedback controller and a gait stabilizer, while the swing phase deploys position control in conjunction with a trajectory planning algorithm to ensure proper footfall. Numerical simulations are carried out for the system with/without control. The control strategy is further validated by simulations of the Simscape multibody model. The overall simulated controller results are promising and demonstrate stable bounding for four system cycles.
26

STRUCTURAL CONTROLS ON EXTENSIONAL-BASIN DEVELOPMENT,TRIASSIC ISCHIGUALASTO FORMATION, NW ARGENTINA

Guthrie, Kristin M. 05 August 2005 (has links)
No description available.
27

Mechanical behaviour of compacted earth with respect to relative humidity and clay content : experimental study and constitutive modelling / Comportement mécanique de la terre compactée par rapport à l'humidité relative et à la teneur en argile : étude expérimentale et modélisation constitutive

Xu, Longfei 04 July 2018 (has links)
La terre compactée est considérée comme un mélange granulaire dans lequel l'argile joue un rôle de liant mais cette dernière exhibe une forte interaction avec l'eau. Pendant la durée de vie en service, la terre compactée est soumise aux changements de l’humidité relative. En raison de ces changements des conditions ambiantes perpétuels, la teneur en eau dans la terre varie, impactant leur performance mécanique. Le présent travail a ainsi pour but d’étudier l’impact de l’humidité relative et de la teneur d'argile sur le comportement mécanique de la terre compactée. Il se réalisera au travers d’études expérimentales et d'une modélisation constitutive. Dans la première partie de cette thèse, quatre terres régionales de provenances et de teneurs d'argile différentes sont identifiées. Une étude comparative a été réalisée entre le double compactage statique et le compactage dynamique. En parallèle, trois types d'essais spécifiques : essais de succion par la méthode de papier-filtre, essais de retrait et essais d'absorption d'eau, ont été menés pour donner des indications préliminaires quant aux effets d'interaction entre l'eau et l'argile. Dans la deuxième partie, l’impact de l’humidité relative et de la teneur d'argile sur le comportement de cisaillement a été étudié, prenant en compte des cycles de chargement-déchargement. En adoptant une définition particulière de la contrainte effective de Bishop, il a également été observé que les états de rupture dans le plan (p'-q) pour tous les échantillons sont alignés approximativement à une ligne droite unique passant par l'origine, quelque soit la succion et la pression de confinement. Sur la base des résultats expérimentaux, un nouveau modèle constitutif a été développé pour la simulation du comportement mécanique de la terre compactée. Ce nouveau modèle a ainsi été formulé dans la cadre de la mécanique de l'endommagement des milieux continus et de la théorie de Bounding Surface Plasticity. / Compacted earth is regarded as a granular mixture in which clay plays a role of binder but it also exhibits an important interaction with water. During their service life, compacted earth can be subject to large changes in relative humidity. Those perpetual changes of environmental conditions induce continuous changes of water content of the earth that impact significantly its mechanical performances. The present work aimes at studying the mechanical behavior of compacted earth with respect to relative humidity and clay content. It involves an extensive experimental study and a constitutive modelling. In the first part of this thesis, four kinds of local earth are identified with different clay contents. A comparison of compaction method was then conducted between a double static compaction and dynamic compaction. Three types of specific tests: suction test by filter paper method, shrinkage test and sorption-desorption test were carried out, thereby providing a preliminary insight on the interaction effects between clay and water. In the second part, the impact of clay and moisture contents on the shear behavior of compacted earth was investigated taking into account loading-unloading cycles. Adopting a particular definition of Bishop's effective stress, failure states of all samples were observed to lie approximately on a unique failure line crossing the origin in the (p'-q) plane regardless of matric suction and confining pressure. Finally, based on the above experimental results, a new constitutive model was proposed, based on the theories of Bounding Surface Plasticity and continuum damage mechanics, aiming to simulate mechanical behaviour of compacted earth.
28

Effective Techniques for Stateless Model Checking

Aronis, Stavros January 2018 (has links)
Stateless model checking is a technique for testing and verifying concurrent programs, based on exploring the different ways in which operations executed by the processes of a concurrent program can be scheduled. The goal of the technique is to expose all behaviours that can be a result of scheduling non-determinism. As the number of possible schedulings is huge, however, techniques that reduce the number of schedulings that must be explored to achieve verification have been developed. Dynamic partial order reduction (DPOR) is a prominent such technique. This dissertation presents a number of improvements to dynamic partial order reduction that significantly increase the effectiveness of stateless model checking. Central among these improvements are the Source and Optimal DPOR algorithms (and the theoretical framework behind them) and a technique that allows the observability of the interference of operations to be used in dynamic partial order reduction. Each of these techniques can exponentially decrease the number of schedulings that need to be explored to verify a concurrent program. The dissertation also presents a simple bounding technique that is compatible with DPOR algorithms and effective for finding bugs in concurrent programs, if the number of schedulings is too big to make full verification possible in a reasonable amount of time, even when the improved algorithms are used. All improvements have been implemented in Concuerror, a tool for applying stateless model checking to Erlang programs. In order to increase the effectiveness of the tool, the interference of the high-level operations of the Erlang/OTP implementation is examined, classified and precisely characterized. Aspects of the implementation of the tool are also described. Finally, a use case is presented, showing how Concuerror was used to find bugs and verify key correctness properties in repair techniques for the CORFU chain replication protocol. / UPMARC / RELEASE
29

Detekce kolize objektů v 3D prostoru / Collision detection in 3D space

Grulich, Jan January 2016 (has links)
Práce se zabývá detekcí kolizí v 3D simulačním prostoru. V první části jsou popsány nejpoužívanější algoritmy pro detekci, stejně jako některé knihovny hotových řešení. Druhá část práce obsahuje popis testovacího softwaru vytvořeného na základě knihovny OpenGL, včetně popisu důležitých částí. V poslední části práce jsou také prezentovány výsledky testování a porovnání vybraných algoritmů na vytvořených testovacích úlohách.
30

Safe human-robot interaction based on multi-sensor fusion and dexterous manipulation planning

Corrales Ramón, Juan Antonio 21 July 2011 (has links)
This thesis presents several new techniques for developing safe and flexible human-robot interaction tasks where human operators cooperate with robotic manipulators. The contributions of this thesis are divided in two fields: the development of safety strategies which modify the normal behavior of the robotic manipulator when the human operator is near the robot and the development of dexterous manipulation tasks for in-hand manipulation of objects with a multi-fingered robotic hand installed at the end-effector of a robotic manipulator. / Valencian Government by the research project "Infraestructura 05/053". Spanish Ministry of Education and Science by the pre-doctoral grant AP2005-1458 and the research projects DPI2005-06222 and DPI2008-02647, which constitute the research framework of this thesis.

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