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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

Modelagem de circuitos neurais do sistema neuromotor e proprioceptor de insetos com o uso da transferência de informação entre conexões neurais / Neural circuits modeling of insects neuromotor system based on information transfer approach and neural connectivity

Wagner Endo 31 March 2014 (has links)
Apresenta-se, neste trabalho, o desenvolvimento de um modelo bioinspirado a partir do circuito neural de insetos. Este modelo é obtido através da análise de primeira ordem dada pelo STA (Spike Triggered Average) e pela transferência de informação entre os sinais neurais. São aplicadas técnicas baseadas na identificação dos atrasos de tempo da máxima coerência da informação. Utilizam-se, para esta finalidade, os conceitos da teoria de informação: a DMI (Delayed Mutual Information) e a TE (Transfer Entropy). Essas duas abordagens têm aplicação em transferência de informação, cada uma com suas particularidades. A DMI é uma ferramenta mais simples do que a TE, do ponto de vista computacional, pois depende da análise estatística de funções densidades de probabilidades de segunda ordem, enquanto que a TE, de funções de terceira ordem. Dependendo dos recursos computacionais disponíveis, este é um fator que deve ser levado em consideração. Os resultados de atraso da informação são muito bem identificados pela DMI. No entanto, a DMI falha em distinguir a direção do fluxo de informação, quando se tem sistemas com transferência de informação indireta e com sobreposição da informação. Nesses casos, a TE é a ferramenta mais indicada para a determinação da direção do fluxo de informação, devido à dependência condicional imposta pelo histórico comum entre os sinais analisados. Em circuitos neurais, estas questões ocorrem em diversos casos. No gânglio metatorácico de insetos, os interneurônios locais possuem diferentes padrões de caminhos com sobreposição da informação, pois recebem sinais de diferentes neurônios sensores para o movimento das membros locomotores desses animais. O principal objetivo deste trabalho é propor um modelo do circuito neural do inseto, para mapear como os sinais neurais se comportam, quando sujeitos a um conjunto de movimentos aleatórios impostos no membro do inseto. As respostas neurais são reflexos provocados pelo estímulo táctil, que gera o movimento na junção femorotibial do membro posterior. Nestes circuitos neurais, os sinais neurais são processados por interneurônios locais dos tipos spiking e nonspiking que operam em paralelo para processar a informação vinda dos neurônios sensores. Esses interneurônios recebem sinais de entrada de mecanorreceptores do membro posterior e da junção motora dos insetos. A principal característica dos interneurônios locais é a sua capacidade de se comunicar com outros neurônios, tendo ou não a presença de impulsos nervosos (spiking e nonspiking). Assim, forma-se um circuito neural com sinais de entradas (neurônios sensores) e saídas (neurônios motores). Neste trabalho, os algoritmos propostos analisam desde a geração aleatória dos movimentos mecânicos e os estímulos nos neurônios sensores que chegam até o gânglio metatorácico, incluindo suas respostas nos neurônios motores. São implementados os algoritmos e seus respectivos pseudocódigos para a DMI e para a TE. É utilizada a técnica de Surrogate Data para inferir as medidas de significância estatística em relação à máxima coerência de informação entre os sinais neurais. Os resultados a partir dos Surrogate Data são utilizados para a compensação dos erros de desvio das medidas de transferência de informação. Um algoritmo, baseado na IAAFT (Iterative Amplitude Adjusted Fourier Transform), gera os dados substitutos, com mesmo espectro de potência e diferentes distribuições dos sinais originais. Os resultados da DMI e da TE com os Surrogate Data fornecem os valores das linhas de base quando ocorre a mínima transferência de informação. Além disso, foram utilizados dados simulados, para uma discussão sobre os efeitos dos tamanhos das amostras e as forças de associação da informação. Os sinais neurais coletados estão disponíveis em um banco de dados com diversos experimentos no gânglio metatorácico dos gafanhotos. No entanto, cada experimento possui poucos sinais coletados simultaneamente; assim, para diferentes experimentos, os sinais ficam sujeitos às variações de tamanho de amostras, além de ruídos que interferem nas medidas absolutas de transferência de informação. Para se mapear essas conexões neurais, foi utilizada a metodologia baseada na normalização e compensação dos erros de desvio para os cálculos da transferência de informação. As normalizações das medidas utilizam as entropias totais do sistema. Para a DMI, utiliza-se a média geométrica das entropias de X e Y , para a TE aplica-se a CMI (Conditional Mutual Information) para a sua normalização. Após a aplicação dessas abordagens, baseadas no STA e na transferência de informação, apresenta-se o modelo estrutural do circuito neural do sistema neuromotor de gafanhotos. São apresentados os resultados com o STA e a DMI para os neurônios sensores, dos quais são levantadas algumas hipóteses sobre o funcionamento desta parte do FeCO (Femoral Chordotonal Organ). Para cada tipo de neurônio foram identificados múltiplos caminhos no circuito neural, através dos tempos de atraso e dos valores de máxima coerência da informação. Nos interneurônios spiking obtiveram-se dois padrões de caminhos, enquanto que para os interneurônios nonspiking identificaram-se três padrões distintos. Esses resultados são obtidos computacionalmente e condizem com que é esperado a partir dos modelos biológicos descritos em Burrows (1996). / Herein, we present the development of a bioinspired model by the neural circuit of insects. This model is obtained by analyzing the first order from STA (Spike Triggered Average) and the transfer of information among neural signals. Techniques are applied based on the identification of the time delays of the information maximum coherence. For this purpose we use the concepts of the theory of information: DMI (Delayed Mutual Information) and TE (Transfer Entropy). These two approaches have applications on information transfer and each one has peculiarities. The DMI is a simpler tool than the TE, from the computational point of view. Therefore, DMI depends on the statistical analysis of second order probability density functions, whereas the TE depends on third order functions. If computational resources are a problem, those questions can be taken into consideration. The results of the information delay are very effective for DMI. However, DMI fails to distinguish the direction of the information flow when we have systems subjected to indirect information transfer and superposition of the information. In these cases, the TE is the most appropriate tool for determining the direction of the information flow, due to the conditional dependence imposed by a common history among the signals. In neural circuits, those issues occur in many cases. For example, in metathoracic ganglion of insects, the local interneurons have different pathways with superposition of the information. Therefore, the interneurons receive signals from different sensory neurons for moving the animals legs . The main objective of this work is propose a model of the neural circuit from an insect. Additionally, we map the neural signals when the hind leg is subjected to a set of movements. Neural responses are reflexes caused by tactile stimulus, which generates the movement of femoro-tibial joint of the hind leg. In these neural circuits, the signals are processed by neural spiking and nonspiking local interneurons. These types of neurons operate in parallel processing of the information from the sensory neurons. Interneurons receive input signals from mechanoreceptors by the leg and the insect knees. The main feature of local interneurons is their ability to communicate with others neurons. It can occur with or without of the presence of impulses (spiking and nonspiking). Thus, they form a neural circuit with input signals (sensory neurons) and outputs (motor neurons). The proposed algorithms analyze the random generation of movements and mechanical stimuli in sensory neurons. Which are processing in the metathoracic ganglion, including their responses in the motor neurons. The algorithms and the pseudo-code are implemented for TE and DMI. The technique of Surrogate Data is applied to infer the measures of statistical significance related to the information maximum coherence among neural signals. The results of the Surrogate Data are used for bias error compensation from information transfer. An algorithm, based on IAAFT (Iterative Amplitude Adjusted Fourier Transform), generates Surrogate Data with the same power spectrum and different distributions of the original signals. The results of the surrogate data, for DMI and TE, achieve the values of baselines when there are minimum information transfer. Additionally, we used simulated data to discuss the effects of sample sizes and different strengths of information connectivity. The collected neural signals are available from one database based on several experiments of the locusts metathoracic ganglion. However, each experiment has few simultaneously collected signals and the signals are subjected of variations in sample size and absolute measurements noisy of information transfer. We used a methodology based on normalization and compensation of the bias errors for computing the information transfer. The normalization of the measures uses the total entropy of the system. For the DMI, we applied the geometric mean of X and Y . Whereas, for the TE is computed the CMI (Conditional Mutual Information) for the normalization. We present the neural circuit structural model of the locusts neuromotor system, from those approaches based on STA and the information transfer. Some results are presented from STA and DMI for sensory neurones. Then, we achieve some new hypothesis about the neurophisiology function of FeCO. For each type of neuron, we identify multiple pathways in neural circuit through the time delay and the information maximum coherence. The spiking interneurons areyielded by two pathways, whereas the nonspiking interneurons has revealed three distinct patterns. These results are obtained computationally and are consistent with biological models described in Burrows (1996).
22

La reconstruction du mouvement du squelette : l'enjeu de l'artefact des tissus mous / The reconstruction of skeletal movement : the soft tissue artefact issue

Bonci, Tecla 08 May 2015 (has links)
Lors de l'analyse 3D du mouvement humain basée sur des marqueurs cutanés, la position des os ne peut être qu'indirectement estimée. Au cours d'une tâche, les déformations des tissus mous génèrent des déplacements des marqueurs par rapport à l'os : les artefacts de tissus mous (STA), entraînant des effets dévastateurs sur l'estimation de la position. La compensation des STA demeure une question ouverte. L'objectif de cette thèse est de contribuer à la solution de cette question cruciale. La modélisation des STA en utilisant des variables spécifiques mesurables est une condition préalable à son élimination. Un modèle corrigeant les trajectoires individuelles de marqueurs de la cuisse, calibré par des mesures directes des STA, est d'abord présenté. Les STA sont modélisés comme une combinaison linéaire des angles articulaires impliqués. Trois représentations des STA par une série de modes sont proposées : déplacements de marqueurs individuels, transformations géométriques de clusters de marqueurs (MCGT), et variations de forme de l'enveloppe de peau. Le MCGT permet de dissocier les composantes rigides et non rigides. Il a été démontré que seule la composante rigide affecte la cinématique articulaire. Un modèle de cette composante est alors défini pour les clusters cuisse et jambe. Un compromis acceptable entre la correction des STA et le nombre de paramètres a ainsi été obtenu. Les principales applications sont de générer une simulation réaliste des STA ; et surtout, en se concentrant sur la composante rigide, le modèle permet une reconstruction satisfaisante des STA avec moins de paramètres, ce qui facilite son incorporation dans un algorithme d'estimation de la position osseuse / In 3D human movement analysis performed using stereophotogrammetry and skin markers, bone pose can be only indirectly estimated. During a task, soft tissue deformations make the markers move with respect to the underlying bone generating soft tissue artefacts (STA), causing devastating effects on pose estimation and its compensation remains an open issue. The thesis’ aim was to contribute to the solution of this crucial issue. Modelling STA using measurable trial-specific variables is a prerequisite for its removal from marker trajectories. Two STA model architectures are proposed. A thigh marker-level model is first presented. STA was modeled as a linear combination of joint angles involved in the task. The model was calibrated with direct STA measures. The considerable number of model parameters led to defining STA approximations. Three definitions were proposed to represent STA as series of modes : individual marker displacements, marker-cluster geometrical transformations (MCGT), and skin envelope shape variations. Modes were selected using two criteria : modal energy and selecting them a priori. The MCGT allows to select either rigid or non-rigid components. It was also demonstrated that only the rigid component affects joint kinematics. A model of thigh and shank rigid component at cluster-level was then defined. An acceptable trade-off between STA compensation and number of parameters was obtained. These results lead to two main potential applications : generate realistic STAs for simulation
23

Life Cycle Assessment of a Road Ferry / Livscykelanalys av en Vägfärja

Ringström, Anna January 2019 (has links)
On a national level, the Swedish Transport Administration (STA) constitute the responsibleauthority for national long-term infrastructure planning in Sweden and therefore has animportant role for limit the environmental load from domestic transport. STA Road Ferries isresponsible actor within STA, for national infrastructure planning connected to public marinetransport and has formulated the goal of net zero GHG emissions by year 2045 for the ferryfleet. Today, yearly operation causes around 38,400 tons CO2-equivalents. Emissions fromconstruction, maintenance and deconstruction of road ferries are yet unknown. In order to reachclimate neutrality, identification of emissions from a life cycle perspective is needed. This study analyses environmental performance of a standard road ferry from an LCAperspective to be used as a baseline in future work towards climate neutrality. The LCA wasconducted in SimaPro 8.4.0 and evaluated thorough EPD (2013) methodology according to theEN 15804 standardisation. The report gives initial baseline values for the road ferry Neptunus and identifies daily operationas major hotspot in terms of total environmental impact from analysed impact categories, butalso construction phase is of importance to consider. The study further concludes that based onlong term goal and vision as STA Road Ferries has formulated them to today, a combination ofchange in construction in terms of material choices and design, together with changed fuelalternative is considered necessary in order to reach Vision 45. Future studies are recommended on this subject to reach the long term goal and vision. Forexample, studies that complement the developed model with more project specific process dataand include more components, and comparative LCA’s between different fuel alternatives. / Trafikverket är den aktör och myndighet som ansvarar för den långsiktiga, nationellainfrastrukturplaneringen i Sverige och som därför har en viktig roll i begränsandet avmiljöpåverkan från landets transportsektor. Färjerederiet är ansvarig aktör inom Trafikverketför nationell infrastrukturplanering och drift kopplat till den statliga inrikessjöfarten i form avfärjedrift. Färjerederiet har idag formulerat det långsiktiga målet att nå nollnetto utsläpp förfärjeflottan till år 2045. Idag orsakar färjedriften 38,400 ton CO2 ekvivalenter årligen vilket dåenbart är utsläpp kopplat till driften. Emissioner från konstruktion, underhåll ochdekonstruktion är dock fortfarande okänt. För att nå total klimatneutralitet behövs såledesidentifiering av emissioner ur ett livscykelperspektiv. Den här studien analyserar miljöprestandan av en standardfärja från Färjerederiets färjeflotta urett livscykelperspektiv med syfte att använda detta som utgångsläge i framtida arbete motklimatneutralitet. Livscykelanalysen genomfördes i SimaPro 8.4.0 och metoden EPD (2013)användes för utvärdering av potentiell miljöbelastning enligt EN 15804 standardiseringen. Resultaten från denna rapport är en utgångspunkt för vidare specialisering, och är baserat pådata från vägfärjan Neptunus. Studien identifierade den dagliga driften som en betydandehotspot för den totala miljöpåverkan utifrån de analyserade påverkanskategorierna, men ävenatt konstruktionen är en viktig del av livscykel att ta hänsyn till. Studien visar vidare att ettkombination av en förändrad konstruktion samt val av bränsle är nödvändigt för att nå delångsiktigt uppsatta målen som finns inom Färjerederiet i form av Vision 45. Framtida studier inom detta område är rekommenderat för att nå de långsiktigt uppsatta målen.Till exempel kan vidare studier göras för att komplettera den upprättade modellen med merprojektspecifik processdata och inkludera fler komponenter, samt utföra jämförandelivscykelanalyser mellan olika bränslealternativ.
24

Analysis of Communication Architecture of GCDC 2011 / Analysis of Communication Architecture of GCDC 2011

Khaksari, Mohammadreza January 2011 (has links)
This thesis report presents a method to analyze the communication architecture for the Intelligent Transportation Systems (ITS). The report also includes a case study on ASN.1 notation and analysis of its encoding rules. Included in the report is also: (i) accompanying instruction on how to use ASN.1 compilers to produce the C/C++ message encoder/decoder, and (ii) analysis of Non-IP communications of Communication Access for Land Mobiles (CALM-FAST) protocol stack in ITS. The thesis is a part of the research project entitled “SCOOP”, a joint project between SCANIA CV AB and KTH. The purpose of this thesis is to contribute to the ultimate goal, which is to equip a vehicle with necessary hardware and software technology to provide a platooning behavior in the GCDC 2011 competition. This goal is achieved by the means of wireless communication system for both vehicle to vehicle and vehicle to road side units communications in the platoon. Overall, this thesis introduces the important usage of ASN.1 in implementation of cut-edge telecommunication systems especially in V2V and V2I communication; and clarifies the CALM-FAST protocol stack in mobile nodes. / Kartlägga CALM-FAST protokollet och hur det användes tillsammans med den i tävlingen GCDC 2011 fastslanga kommunikationsprotokollet. GCDC var ett tävling i kooperativ körning arrangerad och initierad av Hollänska TNO och gick ut på att få fordon att agera tillsammans beserat på information sänt via WLAN 802.11p. ASN.1 användes och ingick i analysen.
25

Perceptions of Educators' Use of English as a Second Language Strategies and Research-Based Practices with English Language Learners in Northeast Tennessee.

Hernandez, Marisol 19 August 2009 (has links) (PDF)
The purpose of the study was to investigate the level of use of English as a second or subsequent language strategies and research-based practices in the instruction of ELL students in Northeast Tennessee. The researcher sought to ascertain the perceptions of educators in Northeast Tennessee about teaching practices and beliefs in regard to the instruction of ELL students and to determine to what level these educators include ESL strategies and ESL research-based practices when teaching ELL students. Participants in the study consisted of regular classroom teachers, English as a second language teachers, and principals from districts identified as ELL low density districts and ELL high density districts. A survey instrument was used to collect the data. The survey instrument was developed using a framework based on published research on proven practices identified and delineated in the literature review. The survey consisted of 45 questions and encompassed 5 dimensions: (a) instructional practices, (b) ESL strategies, (c) principles for building English language learners responsive learning environments, (d) staff development, and (e) instructional strategies. The survey used a 5-point Likert scale with 3 open-ended questions. Findings from the Research-Based Practices Survey were analyzed by using descriptive and inferential statistics. The study used 2-way ANOVA to analyze the data and answer the research questions. The finding of the study revealed significant difference in the mean scores for staff development between administrators and ESL strategies as a function of density and significant difference in the mean scores for staff development between administrators and all teachers (ESL teachers and regular classroom teachers) as a function of density.
26

Biologic Activity of Selected Chemotherapeutic Agents and Small Molecule Inhibitors in Canine Lung Cancer Cell Lines

Clemente-Vicario, Francisco 21 May 2015 (has links)
No description available.
27

An In Vitro Male Germ Cell Assay and Its Application for Detecting Phase Specificity of Genotoxins/Mutagens

Habas, Khaled S.A., Brinkworth, Martin H., Anderson, Diana 29 September 2017 (has links)
No / Genotoxic agents can interact with DNA in germ cells possibly resulting in a heritable trait (germline mutation). Thus, in vitro male germ cell tests, which can detect phase specificity of such agents, could be used by regulatory agencies to help evaluate the potential risk of mutation. The male germ cell system now has a well-established model for studying phase specificity using the STA-PUT velocity sedimentation. On treatment with genotoxic agents, differences in chemical structure and metabolic differences in types of male germ cell lead to differing susceptibilities to genotoxicity, so careful investigation is required for phase specificity. This can yield valuable information about the potential mechanisms involved in the genotoxicity responses and thus increase the significance of the findings. This is especially important because mutations induced in the germline could also affect future generations. In this chapter, we briefly review the field of the male germ cell DNA damage response.
28

Zpracování DPS silových a datových rozvodů pro historickou a památkově chráněnou budovu / Creation of Documentation for construction of power and data wiring for a historical and a listed building

Nestrojil, Martin January 2018 (has links)
This thesis is describing DPS power and data circuits installations for a historical listed building. Firstly, the theory describes requirements for architects and designs, the types of designs, the laws and directives. This part also contains instructions on how to lay the circuits, how to create environmental report and other topics closely related to design and architecture. Secondly, there is description of the design of the power and data installations for the building. The third practical section contains full project design documentation for power and data circuits for this building including technical drawing, environmental report, ground plans of the building, drawings of switchboards and block drawings. The outcome of this report is to present the theory and then create all relevant documentation for this historical building.
29

Modelování elektrických obvodů ve specializovaném paralelním systému / Electric Circuits Simulations in a Specialized Parallel System

Janko, Roman January 2013 (has links)
This work provides an overview of methods for the numerical solution of differential equations. Options of their parallelization, a division of computational operations on multiple microprocessors, are provided with emphasis placed on the Taylor series. The next part of the work is devoted to the description of a specialized parallel system, which was design to fast solving of these equations. Differential equations are appropriate to describe electrical circuits. An important characteristic of each circuit is its behavior in the frequency domain. The aim of this thesis was to design and implement a program which investigate frequency characteristics of AC circuits. A method for analyzing a circuit and automatically assembling corresponding equations is presented. These differential equations are then solved in TKSL. At the end of this work a time consumption is evaluated and compared with Matlab.
30

Evaluation of a Motion Simulation Platform for Vestibulo-Ocular Research / Utvärdering av en rörelsesimuleringsplatform för vestibulo-okulär forskning

Lundberg, Simon January 2014 (has links)
The vestibuloocular reflex can be manually elicited by tilting or rotating the head. Manual techniques serve their purpose well and is the golden standard in the clinical work, but they lack control of velocity and movement pattern. However, motion simulation platforms enable automatic control of both velocity and movement pattern. One motion simulation platform, named BIRGIT, has been built at the Department of Clinical Neurosciences at Karolinska Institutet but has not yet been in service and require a performance evaluation. The objectives with this thesis is to evaluate the accuracy and precision of BIRGIT and evaluate how bodyweight and movement direction impact the performance. The thesis also evaluate whether it is possible to stabilize the head of the patient during the acceleration phase. Repeated measurements of acceleration with different loads, desired ac- celeration, direction and motion type (rotational and translational), are per- formed. Dummies are used to simulate bodyweight in the performance study and real persons are used in the head stabilization study. Analysis of variance (ANOVA) is the main statistical tool. The results suggest that the platform does not perform equally at dif- ferent load or directions and that there is a bias between desired and true acceleration. The main problems are an inclination of the rails, upon which the chair is mounted, that causes differences between directions and an un- desirable performance characteristic for rotational motions. The stabilization study suggest that the head can be stabilized. / Den vestibulo-okul ̈ara reflexen kan framkallas genom att manuellt rotera eller rycka p ̊a huvudet. Att manuellt framkalla reflexen fungerar i de flesta sam- manhang va ̈l och a ̈r standard i m ̊anga underso ̈kningar. Dock g ̊ar det inte att till fullo kontrollera vare sig hastighet eller ro ̈relsebana perfekt. Emellertid g ̊ar detta att kontrollera genom att anva ̈nda sig av en s ̊a kallad ro ̈relsesimu- leringsplatform. En s ̊adan platform, d ̈opt till BIRGIT, har byggts vid Institutionen f ̈or kliniska neurovetenskaper vid Karolinska Institutet. Denna har ej bo ̈rjat anva ̈ndas ̈annu d ̊a dess prestanda fo ̈rst beho ̈ver utv ̈arderas. Syftet med denna uppsats ̈ar att utva ̈rdera precision och noggrannhet hos BIRGIT. Dessutom, att utv ̈ardera hur kroppsvikt och ro ̈relseriktning inverkar p ̊a prestandan. I arbetet ing ̊ar ̈aven att testa om det a ̈r m ̈ojligt att stabilisera huvudet under accelerationsfasen. Repeterade ma ̈tningar av sann acceleration med olika last, riktning, bo ̈rac- celeration och r ̈orelsetyp (rotation eller sidledes) genomfo ̈rdes. Testdockor anva ̈ndes fo ̈r att simulera lasten i prestandatesterna och riktiga testpersoner anva ̈ndes i huvudstabiliseringsdelen. Variansanalys (ANOVA) var det hu- vudsakliga statistiska verktyget. Resultatet antyder att last och ro ̈relseriktning inverkar p ̊a acceleratio- nen och prestandan och att den sanna accelerationen alltigenom a ̈r la ̈gre a ̈n bo ̈raccelerationen. Det finns tv ̊a sto ̈rre problem hos plattformen, det fo ̈rsta a ̈r att uppha ̈ngningen till stolen lutar och detta resulterar i en skillnad mellan riktningarna (det g ̊ar fortare nedf ̈ors). Det andra problemet a ̈r ett cykliskt uppfo ̈rande na ̈r flera rotationsr ̈orelser skall fo ̈lja p ̊a varandra. Stabiliseringsstudien visade att det g ̊ar att stabilisera huvudet.

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