• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 600
  • 161
  • 87
  • 83
  • 69
  • 61
  • 24
  • 24
  • 13
  • 11
  • 9
  • 9
  • 7
  • 5
  • 4
  • Tagged with
  • 1394
  • 314
  • 248
  • 235
  • 202
  • 168
  • 158
  • 132
  • 100
  • 99
  • 86
  • 85
  • 84
  • 82
  • 73
  • 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

Development of a Human Accompanying Wheelchair using Ultrasonic Tethering

Pingali, Theja Ram 05 July 2019 (has links)
In social situations, people who use a powered wheelchair must divide their attention between navigating the chair and conversing with people. As a solution that maintains a good conversation distance between the wheelchair and the accompanying person, a wheelchair control system was introduced to provide automated side-by-side following by wirelessly tethering the wheelchair to the person. This thesis designed, developed, and evaluated a wireless tethering system using ultrasonic sensors. Two ping sensors and three piezoelectric ultrasonic transducers were used to identify the accompanying person and determine their pose. A trajectory algorithm determined the person’s direction of motion and a drive control algorithm determined the wheelchair’s required direction by maintaining a comfortable conversation distance between the person and the wheelchair user. A plug-and-play prototype was developed using commercially available components and the firmware was implemented using an open-source platform. The prototype developed in this thesis was mounted to a Permobil F3 Corpus powered wheelchair with a modified Eightfold Technologies SmartChair Remote, which controlled the wheelchair direction. Results demonstrated that the system can navigate a wheelchair beside an accompanying person and maintain a comfortable conversation distance, which is advantageous for users who require hands-free wheelchair control during social activities.
92

Évaluation de méthodes faible consommation contre les attaques matérielles / Evaluation of low power methods against hardware attacks

Ordas, Sébastien 30 November 2015 (has links)
La consommation des circuits intégrés n'a cessé d'augmenter cette dernière décennie. Avec l'augmentation du prix de l'énergie et la démocratisation des systèmes embarqués, des méthodes permettant de gérer le compromis consommation performance, comme la gestion dynamique de la fréquence et de la tension d'alimentation ou encore du potentiel de substrat, ont été élaborées. Ces méthodes, qui sont de plus en plus couramment mises en œuvre dans les systèmes intégrés, permettent de diminuer la consommation de ceux-ci, et mieux de gérer le compromis consommation performance. Certains de ces circuits, embarquant ces méthodes peuvent avoir à effectuer des opérations traitant des informations confidentielles. Il est donc nécessaire de s'interroger sur l'éventuel impact de ces sur la sécurité des systèmes intégrés. Dans ce contexte, les travaux de thèse reportés dans le présent document, ont eu pour objectif d'analyser la compatibilité de ces méthodes de gestion de la consommation avec la conception de circuits robustes aux attaques matérielles. Plus particulièrement, l'objectif a été de déterminer si ces techniques de conception faible consommation, constituent des obstacles réels ou bien facilitent les attaques matérielles par observation et perturbation exploitant le canal électromagnétique. Dans un premier temps, une étude sur l'efficacité des attaques par observation en présence de gestion aléatoire de la tension, de la fréquence et de la polarisation de substrat a été conduite. Dans un deuxième temps, l'impact de la gestion dynamique des tensions d'alimentation et de substrat sur la capacité à injecter des fautes par médium électromagnétique a été étudié. Ce document présente l'ensemble des résultats de ces analyses.Mots-clés : Attaques Matérielles, Attaques par Canaux Auxiliaires, Attaques par fautes, Canal électromagnétique, DVFS, Body-Biasing. / The consumption of integrated circuits has been increasing over the last decade. With the increase of energy prices and the democratization of embedded systems, methods to manage the consumption performance compromise, such as the dynamic management of the frequency and the supply voltage or the substrate potential, were developed. These methods, which are becoming more commonly implemented in integrated systems, allow to reduce the consumption of those latter, and to better manage the tradeoff between consumption and performance.Some of these circuits, embedding these methods, may have to perform some operations with confidential information. It is therefore necessary to consider the possible impact of these methods on the safety of the integrated systems. In this context, the work reported in this thesis aimed to analyze the compatibility of these methods of power management with the design of robust circuits to physical attacks.Specifically, the objective was to determine whether these low-power techniques constitute real obstacles or facilitate the attacks by observation or perturbation exploiting the electromagnetic channel. Initially, a study on the effectiveness of attacks by observation in the presence of random management of voltage, frequency and substrate polarization was done. Secondly, the impact of the dynamic management of supply voltages and substrate polarization on the ability to inject faults by electromagnetic medium was studied. This document presents the overall results of these analyzes. Keyword : Hardware Attacks, Side Channel Attacks, Faults Attacks, Electromagnetic canal, DVFS, Body-biasing
93

The side-by-side model of DNA: logic in a scientific invention

Stokes, Terence Douglas January 1983 (has links)
Watson and Crick’s double-helical model of DNA is considered to be one of the great discoveries in biology. However, in 1976, two groups of scientists, one in New Zealand, the other in India, independently published essentially the same radical alternative to the double helix. The alternative, Side-By-Side (SBS) or ‘warped zipper’ conformation for DNA is not helical. Rather than intertwine, as do Watson and Crick’s helices, its two exoskeletal strands are topologically independent. Thus, unlike the double helix, they may separated during replication without unwinding. This dissertation presents, but does not arbitrate among scientific arguments. Its concerns are meta-scientific; in particular, why and how the individuals who invented the & ‘warped zipper’ came to do so. Against Popper and most recent philosophers of science, it is taken to be “the business of epistemology to produce what has been called a ‘rational reconstruction’ of the steps that have led the scientist to a discovery [Popper (1972), p.31, emphasis in the original].” On the received view, the invention of the ‘warped zipper’ must be irrational or, at best, non-rational thereby excluding from philosophical investigation. I establish that this philosophical dogma is not true a priori, as is usually supposed, and, in the case of the SBS structure of DNA, false a posteriori. The motivation for, and development of the SBS structure for DNA reveals a process best characterized as significantly, though not entirely, rational.
94

The side-by-side model of DNA: logic in a scientific invention

Stokes, Terence Douglas January 1983 (has links)
Watson and Crick’s double-helical model of DNA is considered to be one of the great discoveries in biology. However, in 1976, two groups of scientists, one in New Zealand, the other in India, independently published essentially the same radical alternative to the double helix. The alternative, Side-By-Side (SBS) or ‘warped zipper’ conformation for DNA is not helical. Rather than intertwine, as do Watson and Crick’s helices, its two exoskeletal strands are topologically independent. Thus, unlike the double helix, they may separated during replication without unwinding. This dissertation presents, but does not arbitrate among scientific arguments. Its concerns are meta-scientific; in particular, why and how the individuals who invented the & ‘warped zipper’ came to do so. Against Popper and most recent philosophers of science, it is taken to be “the business of epistemology to produce what has been called a ‘rational reconstruction’ of the steps that have led the scientist to a discovery [Popper (1972), p.31, emphasis in the original].” On the received view, the invention of the ‘warped zipper’ must be irrational or, at best, non-rational thereby excluding from philosophical investigation. I establish that this philosophical dogma is not true a priori, as is usually supposed, and, in the case of the SBS structure of DNA, false a posteriori. The motivation for, and development of the SBS structure for DNA reveals a process best characterized as significantly, though not entirely, rational.
95

Dynamic analysis of multiple-body floating platforms coupled with mooring lines and risers

Kim, Young-Bok 30 September 2004 (has links)
A computer program, WINPOST-MULT, is developed for the dynamic analysis of a multiple-body floating system coupled with mooring lines and risers in the presence of waves, winds and currents. The coupled dynamics program for a single platform is extended for analyzing multiple-body systems by including all the platforms, mooring lines and risers in a combined matrix equation in the time domain. Compared to the iteration method between multiple bodies, the combined matrix method can include the full hydrodynamic interactions among bodies. The floating platform is modeled as a rigid body with six degrees of freedom. The first- and second-order wave forces, added mass coefficients, and radiation damping coefficients are calculated from the hydrodynamics program WAMIT for multiple bodies. Then, the time series of wave forces are generated in the time domain based on the two-term Volterra model. The wind forces are separately generated from the input wind spectrum and wind force formula. The current is included in Morison's drag force formula. In case of FPSO, the wind and current forces are generated using the respective coefficients given in the OCIMF data sheet. A finite element method is derived for the long elastic element of an arbitrary shape and material. This newly developed computer program is first applied to the system of a turret-moored FPSO and a shuttle tanker in tandem mooring. The dynamics of the turret-moored FPSO in waves, winds and currents are verified against independent computation and OTRC experiment. Then, the simulations for the FPSO-shuttle system with a hawser connection are carried out and the results are compared with the simplified methods without considering or partially including hydrodynamic interactions.
96

A study on the impacts of the economic and trade policies of Taiwan on the development of the automobile industry of Taiwan

Gao, Jin-lai 26 August 2007 (has links)
In the past 10 years, the automobile market of Taiwan has been about 400,000 automobiles per year, and the average output per automaker in Taiwan has been in the range from 30,000 to 50,000 automobiles per year. According to the relevant studies, to reach the goal of economic size of production, 100,000 automobiles should be produced per model per year and the total output of an automaker should be more than 400,000 automobiles. There are 10 automakers in Taiwan. What are the economic and trade policies that have brought about so many automakers in Taiwan? Is this an example of extreme loosening of the control of the automobile industry or if this has something to do with the big profit margin in the industry? Taiwan has entered the WTO; the economic and trade policies of Taiwan should be so set that they can further the development of the automobile industry of Taiwan in the Chinese market and other parts of the world by utilizing the trade advantages of Taiwan. In this study, we look into the changes of the economic and trade policies of Taiwan in terms of their impacts on the automobile industry of Taiwan; we also try to assess the causes of such changes. What are the policies that have caused the evolution of the automobile industry of Taiwan? Why can¡¦t the automakers in Taiwan develop their own brand like the manufacturers in the microelectronic industry, motorcycle industry and bicycle industry in Taiwan? In this study, from the economic perspective and the perspective of the relevant policies, we examine the consumer market and buyers¡¦ preferences on the demand side; while, on the supply side, we look into the competition strategies adopted by the automakers and their competitiveness through the R & D, production technologies and competitiveness of these automakers. We also examine the impacts of the relevant government policies on the automobile industry and the challenges posed by Taiwan¡¦s entry into the WTO. Our aim is to understand the problems and difficulties found in the government policies and the evolution of the automobile industry of Taiwan so that we infer how the government policies will be evolved into and the crucial factors that have caused the changes in the policies. In this study, we look into how the crucial factors have caused the changes in the automobile industry. Through the previously described approaches and the assessment of the policies relating to the automobile industry, we can identify the successful and failure experience in the past and infer the competitive advantages and the policies in the future. Also, through the simulation of the optimal development direction of the policies relating to the automobile industry, we bring forth the future development direction of the automobile industry for the reference of the relevant government agencies so as to create an environment that allows the manufacturers of the industry to establish production facilities in China and to enter other markets of the world and so that the goals of autonomous product development and the sustainable development of the automobile industry of Taiwan may be reached and the products of these manufacturers may be more competitive in terms of the global market.
97

Drivers of eco-innovation

Ahmed, Shohana, Kamruzzaman, Mohammad January 2010 (has links)
Contemporary business world is now facing a challenge, a shift from traditional innovation to eco-innovation. Organizations need to recognize the importance of environment in any aspect of innovation. This paper aims to deduce the drivers of eco-innovation from the overview of existing literature and empirical study to provide an understanding of the organization aiming towards eco-innovation. The aim of this thesis is to identify the drivers of eco-innovation and objectives being able to understand and review the contribution of innovation and eco-innovation as separate entities.This research is limited to the investigation of drivers of eco-innovation in one single organization i.e. Tekniska Verken, Linköping. Conceptual model of drivers of eco-innovation is created from previous research and verified through empirical study. The model of this research is to outline the three categories of drivers within the limit and scope of this analysis. However modification of the model on the basis of additional drivers has been duly appreciated and elucidated to reflect reality of the research.
98

Dynamic analysis of multiple-body floating platforms coupled with mooring lines and risers

Kim, Young-Bok 30 September 2004 (has links)
A computer program, WINPOST-MULT, is developed for the dynamic analysis of a multiple-body floating system coupled with mooring lines and risers in the presence of waves, winds and currents. The coupled dynamics program for a single platform is extended for analyzing multiple-body systems by including all the platforms, mooring lines and risers in a combined matrix equation in the time domain. Compared to the iteration method between multiple bodies, the combined matrix method can include the full hydrodynamic interactions among bodies. The floating platform is modeled as a rigid body with six degrees of freedom. The first- and second-order wave forces, added mass coefficients, and radiation damping coefficients are calculated from the hydrodynamics program WAMIT for multiple bodies. Then, the time series of wave forces are generated in the time domain based on the two-term Volterra model. The wind forces are separately generated from the input wind spectrum and wind force formula. The current is included in Morison's drag force formula. In case of FPSO, the wind and current forces are generated using the respective coefficients given in the OCIMF data sheet. A finite element method is derived for the long elastic element of an arbitrary shape and material. This newly developed computer program is first applied to the system of a turret-moored FPSO and a shuttle tanker in tandem mooring. The dynamics of the turret-moored FPSO in waves, winds and currents are verified against independent computation and OTRC experiment. Then, the simulations for the FPSO-shuttle system with a hawser connection are carried out and the results are compared with the simplified methods without considering or partially including hydrodynamic interactions.
99

Chloramphenicol-induced toxicity on haemopoiesis

江卓庭, Kong, Cheuk-ting. January 1998 (has links)
published_or_final_version / Pathology / Master / Master of Philosophy
100

Real time bidding jako nový způsob nákupu plošné reklamy / Real time bidding as a new way of buying media

Götthans, Ondřej January 2017 (has links)
The thesis presents RTB as a new way of buying media. The theoretical part defines the display advertising market, compares different ways of buying media and deeper describes functions of individual entities within the RTB ecosystem. In the application part are used methods such as the deep interviewing, the primary data analysis from the Adform DSP platform and the content analysis, to characterize the Czech market which is also compared with selected markets of Central and Eastern Europe. A future development of RTB on the Czech market is outlined by means of expert interviews. Shortcomings of the current solution are identified based on comparison and analysis of results of retargeting campaigns for the selected subject. Furthermore, an appropriate modification of a retargeting strategy is proposed with support of experts.

Page generated in 0.1696 seconds