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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

Performance Evaluation of Short Time Dead Reckoning for Navigation of an Autonomous Vehicle / Prestandautvärdering av Dödräkning för Navigering av Förarlöst Fordon

Enberg, David January 2015 (has links)
Utilizing a Global Navigation Satellite System (GNSS) together with an Inertial Navigation System (INS) is today a common integration method to obtain a positioning solution for autonomous systems. Both GNSS and INS have benefits and weaknesses where the best parts from both systems can be combined with a Kalman filter. Because of this complementary nature, it is of interest to look at the robustness of the positioning solution when the Global Navigation Satellite System is temporarily not available. The aim of the thesis has been to investigate different vehicle models and to evaluate their short-time performance using a Dead Reckoning approach. The goal has been to develop a system for a Heavy Duty Vehicle (HDV) and to find out for which time interval a specific model can stay within a certain range when the GNSS is lost. A GNSS outage could for example happen when driving on a highway and passing signs, bridges and especially when driving inside tunnels. Also, for a solution to become commercially interesting, it must be cheap. Therefore, is it common to use so called Micro-Electro-Mechanical-Systems (MEMS) sensors which are of low-cost but suffer from biases, scale factors and temperature dependencies which must be compensated for. The results from the tests show that some models are able to estimate the position with good precision during short time GNSS outages whereas other models do not deliver the required accuracy. The main conclusion is that care should be taken when choosing the vehicle model so that it fits its usage area and the complexity needed to describe its motion. There are also lots of parameters to look at when investigating the best solution, where modeling of the low-cost sensors is one of them.
12

Developing SharePoint add-ins

Jansson, Björn, Maghsoudi, Sebastian January 2017 (has links)
Developing a Microsoft SharePoint-based site is, according to marketing, simple and efficient. Efficiency is increased by giving the developer the option to easily add functionality to the site. One way to add functionality is through so called add-ins. An add-in extends the functionality of the site by running independent code on the client, cloud or a server outside the SharePoint farm. Add-ins can be added to the site through a web-based market or by creating new ones. The general question is if creation of new add-ins is worth the effort. This discussion can begin by investigating what implementation detail is reoccurring when developing this add-ins as well as what part of the process the most time is consuming. By attempting to create add-ins and the same time documenting the progress one can make conclusion regarding said questions. The result shows that the most recurring parts of development is how to manage the incoming data. It also seems as if the most time consuming part of add-in development is the research and construction of functionality that fetch data from the SharePoint-based site. Another part of the result is technical and contains information necessary to understand how the example add-ins are created. The add- ins that is presented in this paper concern document management which is a significant aspect of Microsoft SharePoint.
13

Mechanisms of Adaptive and Maladaptive Plasticity After Spinal Cord Injury

Goltash, Sara 08 January 2024 (has links)
Spinal cord injury (SCI) is a debilitating condition that disrupts the communication between the brain and the spinal cord. Several studies have sought to determine how to revive dormant spinal circuits caudal to the lesion to restore movements in paralyzed patients. So far, recovery levels in human patients have been modest at best. In contrast, animal models of SCI exhibit more recovery of lost function. Recovery of lost function could arise from structural changes in spinal circuits following spinal cord injury. Previous work from our lab has identified dI3 interneurons as a spinal neuron population central to the recovery of locomotor function in spinalized mice. We seek to determine the changes in the circuitry of dI3 interneurons and motoneurons following SCI in adult mice. After a complete transection of the spinal cord at T9-T11 level in transgenic Isl1:YFP mice and subsequent treadmill training at various time points of recovery following surgery, we examined changes in three key circuits involving dI3 interneurons and motoneurons: 1) Sensory inputs from proprioceptive and cutaneous afferents, 2) GABAergic inputs onto sensory afferents (GABApre), 3) Central excitatory glutamatergic synapses from spinal neurons onto dI3 INs and motoneurons. Furthermore, we examined the possible role of treadmill training on changes in synaptic connectivity to dI3 interneurons and motoneurons. Our data suggests that sensory inputs from the periphery labelled by VGLUT1⁺ to dI3 interneurons decrease transiently or only at later stages after injury, whereas levels of VGLUT1⁺ remain the same for motoneurons after injury. Levels of central excitatory inputs labelled by VGLUT2⁺ to dI3 INs and MNs may show transient increases but fall below levels seen in sham-operated mice after a period of time. Levels of GABApre boutons onto the VGLUT1⁺ sensory afferents that project onto to dI3 INs and MNs can rise shortly after SCI, but those increases do not persist. However, levels of these GABApre boutons onto VGLUT1⁺ inputs never fell below levels observed in sham-operated mice. For some synaptic inputs studied, levels were higher in spinal cord-injured animals that received treadmill training, but these increases were observed only at some time points. Changes in spinal circuitry could be maladaptive. For example, spasticity is a common consequence of SCI, disrupting motor function and resulting in significant discomfort. Spasticity may arise from maladaptive changes in spinal circuits. Current models of hindlimb spasticity are lacking, hindering the study of mechanisms or treatments of spasticity. Therefore, we have generated a novel mouse model of SCI-related spasticity that utilizes optogenetics to activate a subset of cutaneous VGLUT2⁺ sensory afferents to produce reliable incidences of hindlimb spasticity. To examine the efficacy of this optogenetic spasticity model, a T9-T10 complete transection injury was performed in Isl1-Vglut2ᒼᵃᵗᒼʰ mice, followed by the implantation of EMG electrodes into the left and right gastrocnemius and tibialis anterior muscles. Beginning at 9 days post-injury, EMG recordings were performed during episodic optogenetic stimulation. During each recording session, an optic fiber coupled to a 470nm wavelength LED was used to deliver light pulses to the palmar surface of each hindpaw. The results of these recordings demonstrated significant increases in the amplitude of EMG responses to the light stimulus from 2 weeks post-injury to 5 weeks post-injury, indicating hyperreflexia. Interestingly, this hyperreflexia was significantly greater in the female cohort in comparison to the males. Incidences of prolonged involuntary muscle contraction and clonus were also detected through EMG and visual observation during the testing period, supporting the presence of spasticity. Overall, the results in my thesis suggest remodelling of spinal circuits involving spinal interneurons that have previously been implicated in the recovery of locomotor function after spinal cord injury in mice. In addition, we have developed an optogenetic mouse model that appears to reliably elicit spasticity in SCI mice and may be valuable for the study of SCI-related limb spasticity mechanisms due to the maladaptive changes within the spinal cord.
14

INS v. Chadha: A Study in Judicial Implementation

Wheeler, Darren A. 19 December 2003 (has links)
No description available.
15

GNSS Signal Processing Techniques for Spoofing Resiliency

Esswein, Michael Craig 03 November 2023 (has links)
Global Navigation Satellite Systems (GNSS) for vehicle navigation and timing are widely relied upon by many users in a variety of different sectors such as transit, financial, military, and many others. There are a number of ways for an agent to purposefully degrade a GNSS user's navigation performance. One such attack is a spoofing attack where the agent transmits signals with the same signal structure as GNSS signals, but they are modified to produce an incorrect navigation solution. Resiliency to these attacks is important for GNSS navigation. Two methods for GNSS resiliency are explored in this dissertation. The first method uses a Controlled Reception Pattern Antenna and receiver in order to obtain direction of arrival estimates of all visible signals and their computed pseudoranges. Two contributions were produced for this method. The first contribution is an optimization of a DoA cost metric that use DoA estimates along with known GNSS ephemerides to distinguish authentic signals from spoofed signals. The second contribution of this work is a combined DoA/pseudorange cost metric to improve the classification of authentic signals from spoofed signals as well as improve its robustness to multi-transmitter spoofing attacks. The second method uses a method known as Chimera, which involves authenticating the civilian L1C GPS signal using a digital signature in the navigation message and punctures in the spreading code. This method can be used to distinguish authentic and spoofed signals, however, a delay between the time the signal is tracked by the receiver and the time when it can be determined authentic is inherent in Chimera and degrades navigation performance. This delay can range from 2 seconds to 3 minutes. Four additional contributions have been made in support of Chimera. The first Chimera contribution is the design and evaluation of a navigation system for Chimera using a tightly coupled GPS/INS extended SRIF that accounts for the Chimera authentication delays. The second Chimera contribution is an investigation into staggering of the authentication times of the GPS satellites in order to improve navigation results. The third Chimera contribution is the development of a RMS or maximum steady-state position error metric to compare the accuracy achieved by different authentication group designs when used in conjunction with the previously discussed filter from the first Chimera contribution. The fourth Chimera contribution investigates different authentication group designs to find groups that will produce low value metrics. These investigations included local authentication group optimization, synthesizing a global design using local designs, and the effects of time and IMU grade. Each of these contributions has a significant impact on improving either the resilience of a GPS receiver to spoofing or the navigation accuracy of a GPS receiver that is inherently resilient to spoofing. / Doctor of Philosophy / Global Positioning System (GPS) navigation and timing plays a pivotal role in a variety of different sectors such as transit, financial, military, and many others. There have been instances where a signal is purposefully generated to look similar to a GPS signal in order to mislead a GPS user of their true position, velocity, and timing. This type of attack is known as a spoofing attack. This dissertation discusses two methods to identify these spoofed signals so that they are not used to disrupt nominal navigation and timing. The first method uses multiple GPS antennas to determine the direction of all visible signals. This dissertation provides an algorithm to distinguish the authentic GPS signals from the spoofed signals using the determined signal directions. The second method is for the GPS satellites to watermark the GPS signal they transmit, using modern encryption techniques, to be able to authenticate incoming signals. This method, however, produces a delay between when the signal is received by a GPS user and when it can be deemed authentic. This delay is a problem for navigation. This dissertation develops techniques for dealing with this delay by incorporating an Inertial Measurement Unit (IMU). This dissertation also proposes the idea to stagger the time that the digital signature, which is needed for signal verification, is sent from different GPS satellites. Lastly, this dissertation investigates how different staggered groupings of GPS satellites improve navigation performance and provides a metric for quantifying the navigation performance of different groupings. Overall, the dissertation's contributions to the first method improve the resilience of a receiver to spoofing attacks while the contributions to the second method improve navigation performance of an inherently resilient method.
16

Elektro mechaninių jutiklių taikymo navigacijai patalpų viduje tyrimas / Research of MEMS Application for Indoor Navigation

Leckas, Darius 16 June 2014 (has links)
Pastarųjų metų technologinė puslaidininkinių trimačių mikro struktūrų gamybos procese pažanga leidžia sukurti vis tikslesnius ir patikimesnius tokio tipo elektromechaninius jutiklius. Gerėjanti tokio tipo jutiklių kokybė atveria naujas jų panaudojimo galimybes. Vena jų – vidaus navigacinė sistema. Tokio tipo sistema reikalauja tikslių pagreičio, kampinio greičio ir kitokio tipo duomenų judėjimo trajektorijai nustatyti. Šiame darbe yra apžvelgtos pagrindinės problemos su kuriomis susiduriama kuriant inercines vidaus navigacines sistemas. Apžvelgti, patikrinti ir pasiūlyti alternatyvūs šių problemų sprendimo metodai. Mechaninių jutiklių taikymo navigacijai patalpų viduje tyrimas. Magistro baigiamasis darbas elektronikos inžinerijos magistro laipsniui. Vilniaus Gedimino technikos universitetas. 2014 m. / Recent technological improvements in micromachining process allows to produce smaller, cheaper and more accurate MEMS sensors. Better accuracy/size ratio increases MEMS sensors application field. One of most precise sensors looking for field is MEMS based indoor navigation system, which requires precise accelerometer/gyros, to ensure error free estimated position. Current gyros and accelerometers are much less precise than standard laser based gyros and bulk accelerometers. This work describes the main problems of using MEMS for inertial navigation and possible solutions, to minimize estimated position error. Research of MEMS application for indoor navigation. Master thesis for electronics engineer master degree. Vilnius Gediminas Technical University. Vilnius 2014 m.
17

Les intéractions d'échange dans le semi-conducteur magnétique dilué ZnO.Co

Ambrosio, Sophie d' 26 June 2013 (has links)
Le travail sur le ZnO:Co rapporté dans ce manuscrit, donne une meilleure compréhension des interactions d'échange dans ce composé. La question des interactions spin-spin dans les DMS est abordée à la fois sur le plan théorique et expérimental. Du point de vue théorique, le modèle du superéchange d'Anderson a été utilisé et étendu, afin d'obtenir les valeurs des constantes d'échange sur l'ensemble de la série des DMS II-VI dopés Mn ou Co. Du point de vue expérimental, la combinaison inédite de trois méthodes expérimentales, la diffusion inélastique de neutrons (ou INS), la résonance paramagnétique électronique (ou EPR), et la méthode de mesure des marches d'aimantation sous champ magnétique intense (ou méthode MST), a permis d'établir, pour la première fois, la valeur des dix plus grandes constantes d'échange du ZnO:Co.Les observations faites par INS permettent de mettre en évidence de façon directe une très forte anisotropie spatiale concernant l'intégrale d'échange des premiers voisins. On établit ainsi J(1)=-25,6K et J(2)=-8,5K, correspondant respectivement à la paire des premiers voisins dans le plan (ab), et à la paire des premeirs voisins hors de ce plan. Ce résultat s'explique, en partie, par la présence dans la structure wurtzite d'une contribution ferromagnétique dans le calcul du superéchange, issue d'un chemin formant une boucle et faisant intervenir deux anions distincts.Les mesures effectuées par EPR et par MST permettent d'établir les constantes d'échange entre voisins à plus grande distance. Ainsi, on obtient: J(3)=-1,07K , J(4)=-0,38K , J(5)=0,35K , J(6)=0,17K , J(7)=-0,16K , J(8)=-0,04K , J(9)=-0,03K , |J(10)|=0,013K. / The work performed on ZnO:Co enables a better understanding of exchange constants. The question of the spin-spin interactions in the Diluted Magnetic Semiconducteur (DMS) is studied from both theoretical and experimental approaches. On the théoretical side, a exchange constants for all the II-VI series doped Mn et CO. On the experimental side, the use of three techniques, Inelastic Neutron Scattering (INS), Electron Paramagnetic Resonance (EPR), and the Magnetization Steps (MST) method, has made it possible to establish, for the first time, the ten largest exchange constants in ZnO:Co.The INS experiments show, in direct way, astrong spatial anisotropy of the nearest enighbor exchange integral J(1)=-25.6 K and J(2)=-8.5 K. This result can be explained, in part, by the presence, in the wurtzite structure, of a looped exchange path which involves two distinct anions and is ferromagnetic. To justify this explanation, our model was expanded to cover the entire II-VI series doped Mn and Co. The concurrent results, for the complete series, between the known experimental data and the theoretical exchange values permit the justification and the validation of our hypotheses.The measures performed by EPR and MST enable, for their part, the establisment of the distant neighbor exchange constants. the two techniques give complementary information, and make it possible to directly observe the exchange constants of ZnO:Co going from the third to the tenth largest value, J(3)=-1.07 K ,J(4)=-0.38 K , J(5)=+0.35 K , J(6)=+0.17 K , J(7)=-0.13 K , J(8)=-0.04 K , J(9)=-0.03 K , |J(10)|=0.01 K.
18

O uso de sistema inercial para apoiar a navegação autônoma. / The usage of inertial system to support autonomous navigation.

Mori, Anderson Morais 17 May 2013 (has links)
A proposta deste trabalho é contribuir com a construção de uma plataforma de veículo autônomo para viabilizar as pesquisas na área pelo Departamento de Engenharia de Transportes da USP. Até o momento o departamento dispõe de uma plataforma que, a partir de sua posição conhecida, consegue navegar autonomamente até um ponto de destino utilizando apenas uma solução GNSS, no caso, GPS. Para ampliar a mobilidade da plataforma, está sendo sugerida aqui, a adição de sensores inerciais ao veículo, para que ele consiga obter uma solução de posição mesmo em áreas sem cobertura GNSS. Um Sistema de Navegação Inercial não depende de infraestrutura externa, exceto para inicializar suas variáveis, o que neste caso pode ser feito com auxílio de um receptor GPS. Sensores inerciais de alto desempenho são caros, tem alta complexidade mecânica e em geral são de grande porte. A alternativa é o uso de sensores do tipo MEMS que são pequenos, fáceis de serem manipulados e apresentam baixo consumo de energia. A contrapartida é que a solução é mais susceptível a ruído do que seus pares que custam na faixa de centena de milhões de dólares. / The proposal of this paper is to build an autonomous vehicle platform to enable the researches in this area by the Transport Engineering Department of the USP. Until now the Department has a platform that, once its initial position is known, it can navigate autonomously to a destination point using only the GNSS, in this case, GPS. To expand the mobility resources of the platform, it is being suggested here the addition of inertial sensors to the vehicle, enabling it to acquire a position solution even in areas where there is no coverage of the GNSS. An Inertial Navigation System does not depend on an external infra-structure, with the exception on the initial setup, where the GPS can be used to provide this kind of initialization. High performance inertial sensors are expensive, have high mechanical complexity and in general are big. The alternative is the usage of MEMS sensors, which are small, easy to handle and has low power consumption. In the opposite side this solution is more susceptible to noises in comparison to those High performance sensors that cost hundreds of thousands of dollars.
19

O transporte de ânions em células INS-1E não compõe parte do mecanismo da via de amplificação da secreção de insulina estimulada pela glicose. / The anion transport in INS-1E cell line do not composes part of the mechanism of the amplification pathway of glucose stimulated insulin secretion.

Araujo, Daniel Blanc 22 August 2016 (has links)
A via de amplificação da secreção de insulina estimulada por glicose (GSIS) é um fenômeno discutido na literatura, cujos componentes são amplamente debatidos. Evidências sugerem que a condutância a Cl- compõe parte desta via. Porém, o mecanismo pelo qual essa condutância desempenharia papel na via de amplificação ainda é debatido, e, além disso, as ferramentas farmacológicas para estudo dessas afeta o transporte de outros ânions, como bicarbonato (HCO3-). Buscamos neste trabalho compreender a contribuição do transporte desses ânions para a via de amplificação da GSIS levando em consideração a distribuição de Cl- e HCO3- extracelular em células INS-1E. Concluímos que o transporte de ânions nas células INS-1E não contribui para a via de amplificação da GSIS, porém essas células não expressaram os canais CFTR e Anoctamina 1 que foram relacionados com esse fenômeno. Acreditamos que em células secretoras de insulina que expressem esses canais, o transporte de ânions possua alguma relevância funcional. / The amplification pathway of glucose stimulated insulin secretion (GSIS) is a phenomenon discussed in the literature, which components are broadly debated. Evidence suggests that Cl- conductance composes part of this pathway. However, the mechanism that this conductance would play role on the amplification pathway still is debated, and, besides that, the pharmacological tools to study these affects transport of other anions, such as bicarbonate (HCO3-). We aimed in this study to understand the contribuition of anion transport for the amplification of GSIS considering the Cl- and HCO3- extracellular distribuition in INS-1E cells. We concluded that anion transport in INS-1E cell line do not contribute for the amplification pathway of GSIS, however those cells do not express CFTR and Anoctamin 1 channels which were related with this phenomenon. We believe that in insulin secretin cells that express those channels, the anion transport may have a functional relevance.
20

O transporte de ânions em células INS-1E não compõe parte do mecanismo da via de amplificação da secreção de insulina estimulada pela glicose. / The anion transport in INS-1E cell line do not composes part of the mechanism of the amplification pathway of glucose stimulated insulin secretion.

Daniel Blanc Araujo 22 August 2016 (has links)
A via de amplificação da secreção de insulina estimulada por glicose (GSIS) é um fenômeno discutido na literatura, cujos componentes são amplamente debatidos. Evidências sugerem que a condutância a Cl- compõe parte desta via. Porém, o mecanismo pelo qual essa condutância desempenharia papel na via de amplificação ainda é debatido, e, além disso, as ferramentas farmacológicas para estudo dessas afeta o transporte de outros ânions, como bicarbonato (HCO3-). Buscamos neste trabalho compreender a contribuição do transporte desses ânions para a via de amplificação da GSIS levando em consideração a distribuição de Cl- e HCO3- extracelular em células INS-1E. Concluímos que o transporte de ânions nas células INS-1E não contribui para a via de amplificação da GSIS, porém essas células não expressaram os canais CFTR e Anoctamina 1 que foram relacionados com esse fenômeno. Acreditamos que em células secretoras de insulina que expressem esses canais, o transporte de ânions possua alguma relevância funcional. / The amplification pathway of glucose stimulated insulin secretion (GSIS) is a phenomenon discussed in the literature, which components are broadly debated. Evidence suggests that Cl- conductance composes part of this pathway. However, the mechanism that this conductance would play role on the amplification pathway still is debated, and, besides that, the pharmacological tools to study these affects transport of other anions, such as bicarbonate (HCO3-). We aimed in this study to understand the contribuition of anion transport for the amplification of GSIS considering the Cl- and HCO3- extracellular distribuition in INS-1E cells. We concluded that anion transport in INS-1E cell line do not contribute for the amplification pathway of GSIS, however those cells do not express CFTR and Anoctamin 1 channels which were related with this phenomenon. We believe that in insulin secretin cells that express those channels, the anion transport may have a functional relevance.

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