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1
Wright, Paul. "The cognitive responses to UK railway signals during train driving." Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/75682/.
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When a train driver’s error results in a red, stop signal being passed without authority there is the potential for disaster. These events are termed a “SPAD”, signal passed at danger without authority. Occasionally these incidents have led to tragedies such as the Ladbroke Grove accident in 1999. This accident led to 31 fatalities and over 523 injuries. Investigations of incidents have resulted in safety advancements that decreased the number of incidents and accidents. Despite all these efforts SPADs still occur and very little is known about the cognitive effects that the track-side signalling system has on the driver during normal operational conditions. The motivation for understanding the cognitive and behavioural effects of the routine patterns of railway signalling is to identify potential high and low risk situations. The identification of neural correlates that predict the driver’s state of readiness prior to a potentially dangerous situation. The combination of knowledge of these events and the insights into their causes could allow better systems, operational methods and logistics to be designed. This is an Electroencephalograph, (EEG) study to identify neural correlates that are used to identify high and low risk response and perceptual accuracy situations. The behavioural data is recorded from the keyboard responses and used to guide the EEG analysis. The tools applied to solving the research problem are artefact detection and removal from the EEG data, followed by analysis for patterns and features. The phase-locking functional-connectivity reveals repetition priming, antipriming, and neural precursors to correct and erroneous responses. The phase-locking for certain graph metrics are found to vary significantly prior to response errors. The EEG analysis reveals that multiple cortical region coordinated cognitive activity is required to successfully perform multiple paradigm tasks. Certain channels and regions of the brain are important in creating a cognitive state that facilitated future correct responses. Different states are required to promote response accuracy for different forthcoming events.
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Wahlqvist, Emanuel. "Pre-study of new electrical coupling between train cars." Thesis, Uppsala universitet, Signaler och System, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-167452.
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This study is meant to be an initial study of the possibility to replace the discrete control signal wires over the electrical coupler between train cars with a data bus system. The reason for this is that the electrical coupler is large and heavy due to the high amount of contacts it contains. It is also a problem for manufacturers who are upgrading an existing fleet and need to transfer more signals through a coupler with no spare contacts to use. Except the control signals there are also Ethernet and power signals in the electrical coupler. Some trains also use a bus system for control signals and/or signals containing a large amount of data such as passenger information.This report gives a presentation of some common ways to distribute electrical signals throughout a train used by most manufacturers. It also presents some design recommendations for a system that would collect existing signals to a bus system and two different design proposals that should be considered if such a system is to be developed. The study shows that there are already systems on the market for transferringcontrol signals over a bus but they are more aimed for trains under construction. Forthis reason a new bus system would only be suitable for upgrading existing couplersto free up space in the electrical coupler unit.
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Marcoux, Curtis. "Encoding of Sensory Signals Through Balanced Ionotropic Receptor Dynamics and Voltage Dependent Membrane Noise." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34440.
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Encoding behaviorally relevant stimuli in a noisy background is critical for animals to survive in their natural environment. We identify core biophysical and synaptic mechanisms that permit the encoding of low frequency signals in pyramidal neurons of the weakly electric fish Apteronotus leptorhynchus, an animal that can accurately encode miniscule (0.1%) amplitude modulations of its self-generated electric field. We demonstrate that slow NMDA-R mediated EPSPs are able to summate over many interspike intervals of the primary electrosensory afferents (EAs), effectively eliminating the EA spike train serial correlations from the pyramidal cell input. This permits stimulus-evoked changes in EA spiking to be transmitted efficiently to downstream ELL pyramidal cells, where a dynamic balance of NMDA-R and GABA-A-R currents is critical for encoding low frequency signals. Interestingly, AMPA-R activity is depressed and plays a negligible role in the generation of action potentials; instead, cell intrinsic membrane noise implements voltage-dependent stochastic resonance to amplify weak sensory input and appears to drive a significant proportion of pyramidal cell spikes. Together, these mechanisms may be sufficient for the ELL to encode signals near the threshold of behavioral detection.
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McCamey, Morgan R. "Deep Learning for Compressive SAR Imaging with Train-Test Discrepancy." Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1624266549100904.
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Veillard, Damien. "Etude et analyse des signaux d une centrale inertielle MEMS : application à la reconstruction du mouvement d un convoi ferroviaire." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT311.
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La localisation précise d’un train sur la voie ferrée est une information vitale pour la gestion du trafic et la sécurité des passagers. Le système européen de contrôle des trains (ETCS) embarque ainsi un accéléromètre mono axe mesurant l’accélération longitudinale du train. Ce capteur est l’un des nombreux capteurs présents à bord permettant une odométrie précise. Cependant, sa mesure est faussée par la projection de la gravité sur l’axe sensible en fonction de l’inclinaison de la voie. L’objectif de ce mémoire est donc d’augmenter l’intérêt de ce capteur en développant une solution basée sur une centrale inertielle complète dans le but de fournir une accélération longitudinale fiable. Pour cela, un estimateur d’état a été développé à partir d’un filtre de Kalman étendu et de la prise en compte de contraintes sur le vecteur d’état. L’utilisation d’une équation de réactualisation du gain de Kalman force ainsi l’estimation d’état à évoluer dans un espace contraint. De plus, le vecteur d’observation du système a été augmenté par les informations fournies par un estimateur de vitesse et un estimateur d’attitude du train. L’estimateur de vitesse utilise une analyse fréquentielle des mesures accélérométriques et l’estimateur d’attitude exploite la complémentarité fréquentielle des mesures gyrométriques et accélérométriques pour estimer les angles de roulis et de tangage. Ces informations sont ensuite fusionnées avec les mesures de la centrale. Enfin, des expérimentations ont été réalisées en Turquie dans un train et les performances de l’estimateur ont été validées en comparant les résultats obtenus aux données fournies par une centrale de navigation haut de gammeThe precise location of a train on the rail network is vital information for traffic management and passenger safety. The European Train Control System (ETCS) features a single-axis accelerometer which measures the longitudinal acceleration of the train. This sensor is one of many sensors onboard providing a precise odometry. However, its measurement is corrupted by the projection of the gravity on the sensitive axis as a function of the inclination of the track. The purpose of this work is to increase the value of this sensor by developing a solution based on a complete inertial system in order to provide a reliable longitudinal acceleration. For this, a state estimator was developed based on an extended Kalman filter and the consideration of constraints on the state vector. The use of updating equation of the Kalman gain forces the state estimation to evolve in a constrained space. In addition, the observation vector has been increased with the information provided by a velocity estimator and a train attitude estimator. The velocity estimator uses a frequency analysis of the accelerometer measurements and the attitude estimator operates the frequency complementarity of gyro and accelerometer measurements, to estimate the roll and pitch angles. This information is then merged with the measurements of the IMU. Finally, experiments were carried out in Turkey on a train and the estimator's performance was validated by comparing the results with data from a high-performance inertial navigation system
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Larson, P. T., and D. A. Sheaffer. "TRANSIENT REDUCTION ANALYSIS using NEURAL NETWORKS (TRANN)." International Foundation for Telemetering, 1992. http://hdl.handle.net/10150/608892.
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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, CaliforniaOur telemetry department has an application for a data categorization/compression of a high speed transient signal in a short period of time. Categorization of the signal reveals important system performance and compression is required because of the terminal nature of our telemetry testing. Until recently, the hardware for the system of this type did not exist. A new exploratory device from Intel has the capability to meet these extreme requirements. This integrated circuit is an analog neural network capable of performing 2 billion connections per second. The two main advantages of this chip over traditional hardware are the obvious computation speed of the device and the ability to compute a three layer feed-forward neural network classifier. The initial investigative development work using the Intel chip has been completed. The results from this proof of concept will show data categorization/compression performed on the neural network integrated circuit in real time. We will propose a preliminary design for a transient measurement system employing the Intel integrated circuit.
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Hedberg, Erik, and Mikael Hammar. "Train Localization and Speed Estimation Using On-Board Inertial and Magnetic Sensors." Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-121620.
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Positioning systems for trains are traditionally based on track-side infrastructure, implying costs for both installation and maintenance. A reliable on-board system would therefore be attractive. Sufficient reliability for on-board systems is likely going to require a multi-sensor solution. This thesis investigates how measurements from bogie-mounted inertial and magnetic sensors can contribute to such a system. The first part introduces and compares two different methods for estimating the speed. The first one estimates the fundamental frequency of the variations in the magnetic field, and the second one analyses the mechanical vibrations using the accelerometer and gyro, where one mode is due to the wheel irregularities. The second part introduces and evaluates a method for train localization using magnetic signatures. The method is evaluated both as a solution for localization along a given track and at switchways. Overall, the results in both parts show that bogie-mounted inertial and magnetic sensors provide accurate estimates of both speed (within 0.5 m/s typically) and location (3-5 m accuracy typically).
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Tallfors, Mats. "Parameter estimation and model based control design of drive train systems." Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285.
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Pulugurtha, Satya Venkata Sidhi Vinayak, and Kishore Kumar Atragadda. "A Multi-layered Routing Technique for Sensing Train Integrity and Composition." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-19489.
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This thesis deals with an approach to monitor the integrity and composition of cargo wagons withthe help of Wireless Sensor Network (WSN). The WSN is to be fully automated that does notneed any human intervention for gathering information about the composition and integrity ofcargo trains, which are the most necessary factors for Cargo Logistics. The nodes are deployed inevery wagon along with the master node in the main locomotive. The master node in thelocomotive gets the information from the slave nodes placed in the cargo wagons in successivesessions. If there are any unexpected changes in the composition of the wagon, theacknowledgments to the locomotive will be terminated. This approach mainly focuses ondesigning energy-efficient as well as cost-efficient WSN. The designed WSN can accommodateto changes, which are caused by external conditions. The designed approach is also scalable. TheWSN is designed with the usage of Zigbee mesh protocol with Arduino Microcontroller as thebrain of the system that is validated and verified in the indoor, imitating the railway environment.
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Sundberg, Simon. "Localization of eNodeBs with a Large Set of Measurements from Train Routers." Thesis, Karlstads universitet, Institutionen för matematik och datavetenskap (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-75456.
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This master thesis investigates the possibility of locating LTE base stations, known as eNodeBs, using signal measurements collected by routers on trains. Four existing algorithms for transmitter localization are adopted: the centroid, strongest signal, Monte Carlo path loss simulation and power difference of arrival (PDoA) methods. An improved version of Monte Carlo path loss simulation called logloss fitting is proposed. Furthermore, a novel localization method called sector fitting is presented, which operates solely on the cell identity and geographical distribution of the measurements. The methods are evaluated for a set of manually located eNodeBs, and the results are compared to other external systems that can be used to locate eNodeBs. It is found that the novel sector fitting algorithm is able to considerably improve the accuracy of the logloss fitting and PDoA methods, but weighted centroid is overall the most accurate of the considered methods, providing a median error of approximately 1 km. The Google Geolocation API and Mozilla Location Service still provides estimates that are generally closer to the true location than any of the considered methods. However, for a subset of eNodeBs where measurements from all sectors are available, the novel sector fitting algorithm combined with logloss fitting outperforms the external systems. Therefore, a hybrid approach is suggested, where sector fitting combined with logloss fitting or weighted centroid is used to locate eNodeBs that have measurements from all sectors, while Google Geolocation API or Mozilla Location Service is used to locate the remaining eNodeBs. It is concluded that while the localization performance for those eNodeBs that have measurements from all sectors is relatively good, further improvements to the overall results can likely be obtained in future work by considering environmental factors, the angular losses introduced by directional antennas, and the effects of downlink power control.
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Khoshniyat, Fahimeh. "Optimization-Based Methods for Revising Train Timetables with Focus on Robustness." Licentiate thesis, Linköpings universitet, Kommunikations- och transportsystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132920.
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With increase in the use of railway transport, ensuring robustness in railway timetables has never been this important. In a dense railway timetable even a small disturbance can propagate easily and affect trains' arrival and departure times. In a robust timetable small delays are absorbed and knock-on effects are prevented effectively. The aim of this thesis is to study how optimization tools can support the generation of robust railway traffic timetables. We address two Train Timetabling Problems (TTP) and for both problems we apply Mixed Integer Linear Programming (MILP) to solve them from network management perspectives. The first problem is how robustness in a given timetable can be assessed and ensured. To tackle this problem, a headway-based method is introduced. The proposed method is implemented in real timetables and evaluated from performance perspectives. Furthermore, the impact of the proposed method on capacity utilization, heterogeneity and the speed of trains, is monitored. Results show that the proposed method can improve robustness without imposing major changes in timetables. The second problem addressed in the thesis is how robustness can be assessed and maintained in a given timetable when allocating additional traffic and maintenance slots. Different insertion strategies are studied and their consequences on capacity utilization and on the properties of the timetables are analyzed. Two different insertion strategies are considered: i) simultaneous and ii) stepwise insertion. The results show that inserting the additional trains simultaneously usually results in generating more optimal solutions. However, solving this type of problem is computationally challenging. We also observed that the existing robustness metrics cannot capture the essential properties of having more robust timetables. Therefore we proposed measuring Channel Width, Channel Width Forward, Channel Width Behind and Track Switching. Furthermore, the experimental analysis of the applied MILP model shows that some cases are computationally hard to solve and there is a need to decrease the computation time. Hence several valid inequalities are developed and their effects on the computation time are analyzed. This thesis contains three papers which are appended. The results of this thesis are of special interests for railway traffic planners and it would support their working process. However, railway traffic operators and passengers also benefit from this study.
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Chaine, Alexis Serge. "The evolution of multiple sexual signals in a passerine : trait structure and selection in a dynamic world /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Tran, Florian [Verfasser]. "Autophagy and endoplasmic reticulum stress coordinate protective interleukin-22 signals in the intestinal epithelium. / Florian Tran." Kiel : Universitätsbibliothek Kiel, 2019. http://d-nb.info/1186706635/34.
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Le, Bouar Philippe. "Surveillance automatique des trains en marche pesage dynamique des circulations /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37615098b.
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Silva, José Vicente da. "Padrões de organização e atributos funcionais de plantas em comunidades em estágio inicial e avançado de sucessão em floresta com araucária." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/54436.
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Em ecologia de comunidades buscam-se padrões reproduzíveis, dentre os quais se destaca a busca por regras de montagem ou padrões de organização de comunidades. Diante disso propomos a avaliação desses padrões, com base em convergência e divergência de atributos (TCAP – trait convergence assembly patterns e TDAP – trait divergence assembly patterns, respectivamente), e da influência filogenética na organização de assembléias de espécies lenhosas em florestas. As comunidades foram descritas a partir de atributos funcionais de espécies vegetais, considerando um gradiente sucessional de Floresta Ombrófila Mista, entre áreas que sofreram supressão total da vegetação (denominadas comunidades iniciais) e áreas que não sofreram intervenções expressivas (comunidades avançadas). Para tal, as espécies amostradas, tanto para o estrato superior (indivíduos com DAP ≥ 10 cm), quanto para o estrato inferior (indivíduos com altura > 0,10 m e até 1 cm de DAP), que apresentaram frequência superior a 10%, considerando a amostragem total, foram descritas a partir de 17 atributos funcionais e por relações filogenéticas. Os dados foram analisados a partir de algoritmos baseados em multiplicação e correlações parciais entre diferentes matrizes, que possibilitam discriminar a relevância de TCAP, TDAP e do sinal filogenético para os padrões. Os resultados indicaram que está ocorrendo estruturação das comunidades vegetais a partir dos padrões avaliados, seja convergência ou divergência, relacionados, também, com a filogenia. Diante disso, avaliamos fatores abióticos (filtros ambientais) e bióticos (filtros bióticos) exercem efeitos distintos em comunidades ao longo de um gradiente sucessional, sendo possível observar, também, o sinal filogenético nessas.In community ecology reproducible patterns are sought, among which stands out the search for assembly rules or assembly patterns. Considering this we propose to evaluate these patterns, based on convergence and divergence of attributes (TCAP – trait convergence assembly patterns and TDAP – trait divergence assembly patterns, respectively) and the phylogenetic influence in the organization of assemblages of woody species in forests. The communities were described from functional traits of plant species, considering a successional gradient of Araucaria Forest, among areas subjected to total removal of vegetation (called initial communities) and areas that haven’t suffered significant interventions (advanced communities). To this end, the species sampled for both the upper stratum (individuals with DBH ≥ 10 cm), and for the lower stratum (individuals with height > 0.10 m and until 1 cm DBH), which had a frequency exceeding 10%, considering the total sampling, were described from 17 functional attributes and phylogenetic relationships. Data were analyzed using algorithms based on multiplication and partial correlations between different matrixes, which permit to discriminate the relevance of TCAP, TDAP and phylogenetic signal to the patterns. The results indicated that is occurring organization of plant communities from the patterns assessed, either convergence or divergence, related also with the phylogeny. Given this, we conclude that abiotic (environmental filters) and biotic (biotic filters) factors exert distinct effects on communities along a successional gradient, and it was possible to observe also the phylogenetic signal in these.
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Marek, Michal. "Tester vlakového zabezpečovače." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-318161.
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The Master´s thesis describes continuous automatic train protection system and its functional properties, principally the transmission of special encoded signal between stationary part and rail vehicle. There is also summarized some important information about the gear rotational speed sensors and its communication with other onboard peripherals. Depends by analysed parameters of electrical signals, the general suggestion of portable electronic device is outlined. Portable electronic device or TESTER will be used to in phase of testing mobile part of automatic train protection system mounted onboard of rail vehicle. Tester will generate equivalent electrical signals to signals in system automatic train protection and the real system response will be possible to evaluate. The generator block allows to model real electrical signals in automatic train protection technology type LS or type EVM and signals rail vehicle odometry.
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Riedel, Philipp, Mark J. Jacob, Dirk K. Müller, Nora C. Vetter, Michael N. Smolka, and Michael Marxen. "Amygdala fMRI Signal as a Predictor of Reaction Time." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-214196.
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Reaction times (RTs) are a valuable measure for assessing cognitive processes. However, RTs are susceptible to confounds and therefore variable. Exposure to threat, for example, speeds up or slows down responses. Distinct task types to some extent account for differential effects of threat on RTs. But also do inter-individual differences like trait anxiety. In this functional magnetic resonance imaging (fMRI) study, we investigated whether activation within the amygdala, a brain region closely linked to the processing of threat, may also function as a predictor of RTs, similar to trait anxiety scores. After threat conditioning by means of aversive electric shocks, 45 participants performed a choice RT task during alternating 30 s blocks in the presence of the threat conditioned stimulus [CS+] or of the safe control stimulus [CS-]. Trait anxiety was assessed with the State-Trait Anxiety Inventory and participants were median split into a high- and a low-anxiety subgroup. We tested three hypotheses: (1) RTs will be faster during the exposure to threat compared to the safe condition in individuals with high trait anxiety. (2) The amygdala fMRI signal will be higher in the threat condition compared to the safe condition. (3) Amygdala fMRI signal prior to a RT trial will be correlated with the corresponding RT. We found that, the high-anxious subgroup showed faster responses in the threat condition compared to the safe condition, while the low-anxious subgroup showed no significant difference in RTs in the threat condition compared to the safe condition. Though the fMRI analysis did not reveal an effect of condition on amygdala activity, we found a trial-by-trial correlation between blood-oxygen-level-dependent signal within the right amygdala prior to the CRT task and the subsequent RT. Taken together, the results of this study showed that exposure to threat modulates task performance. This modulation is influenced by personality trait. Additionally and most importantly, activation in the amygdala predicts behavior in a simple task that is performed during the exposure to threat. This finding is in line with “attentional capture by threat”—a model that includes the amygdala as a key brain region for the process that causes the response slowing.
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Teare, Carolyn J. "Spatial and temporal patterns of chemical solute signals in sixteen small tundra streams of the Trail Valley Creek Watershed in the western Canadian arctic." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ37644.pdf.
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Zniyed, Yassine. "Breaking the curse of dimensionality based on tensor train : models and algorithms." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS330.
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Le traitement des données massives, communément connu sous l’appellation “Big Data”, constitue l’un des principaux défis scientifiques de la communauté STIC.Plusieurs domaines, à savoir économique, industriel ou scientifique, produisent des données hétérogènes acquises selon des protocoles technologiques multi-modales. Traiter indépendamment chaque ensemble de données mesurées est clairement une approche réductrice et insatisfaisante. En faisant cela, des “relations cachées” ou des inter-corrélations entre les données peuvent être totalement ignorées.Les représentations tensorielles ont reçu une attention particulière dans ce sens en raison de leur capacité à extraire de données hétérogènes et volumineuses une information physiquement interprétable confinée à un sous-espace de dimension réduite. Dans ce cas, les données peuvent être organisées selon un tableau à D dimensions, aussi appelé tenseur d’ordre D.Dans ce contexte, le but de ce travail et que certaines propriétés soient présentes : (i) avoir des algorithmes de factorisation stables (ne souffrant pas de probème de convergence), (ii) avoir un faible coût de stockage (c’est-à-dire que le nombre de paramètres libres doit être linéaire en D), et (iii) avoir un formalisme sous forme de graphe permettant une visualisation mentale simple mais rigoureuse des décompositions tensorielles de tenseurs d’ordre élevé, soit pour D > 3.Par conséquent, nous nous appuyons sur la décomposition en train de tenseurs (TT) pour élaborer de nouveaux algorithmes de factorisation TT, et des nouvelles équivalences en termes de modélisation tensorielle, permettant une nouvelle stratégie de réduction de dimensionnalité et d'optimisation de critère des moindres carrés couplés pour l'estimation des paramètres d'intérêts nommé JIRAFE.Ces travaux d'ordre méthodologique ont eu des applications dans le contexte de l'analyse spectrale multidimensionelle et des systèmes de télécommunications à relaisMassive and heterogeneous data processing and analysis have been clearly identified by the scientific community as key problems in several application areas. It was popularized under the generic terms of "data science" or "big data". Processing large volumes of data, extracting their hidden patterns, while preforming prediction and inference tasks has become crucial in economy, industry and science.Treating independently each set of measured data is clearly a reductiveapproach. By doing that, "hidden relationships" or inter-correlations between thedatasets may be totally missed. Tensor decompositions have received a particular attention recently due to their capability to handle a variety of mining tasks applied to massive datasets, being a pertinent framework taking into account the heterogeneity and multi-modality of the data. In this case, data can be arranged as a D-dimensional array, also referred to as a D-order tensor.In this context, the purpose of this work is that the following properties are present: (i) having a stable factorization algorithms (not suffering from convergence problems), (ii) having a low storage cost (i.e., the number of free parameters must be linear in D), and (iii) having a formalism in the form of a graph allowing a simple but rigorous mental visualization of tensor decompositions of tensors of high order, i.e., for D> 3.Therefore, we rely on the tensor train decomposition (TT) to develop new TT factorization algorithms, and new equivalences in terms of tensor modeling, allowing a new strategy of dimensionality reduction and criterion optimization of coupled least squares for the estimation of parameters named JIRAFE.This methodological work has had applications in the context of multidimensional spectral analysis and relay telecommunications systems
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Riedel, Philipp, Mark J. Jacob, Dirk K. Müller, Nora C. Vetter, Michael N. Smolka, and Michael Marxen. "Amygdala fMRI Signal as a Predictor of Reaction Time." Frontiers Research Foundation, 2016. https://tud.qucosa.de/id/qucosa%3A29972.
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Reaction times (RTs) are a valuable measure for assessing cognitive processes. However, RTs are susceptible to confounds and therefore variable. Exposure to threat, for example, speeds up or slows down responses. Distinct task types to some extent account for differential effects of threat on RTs. But also do inter-individual differences like trait anxiety. In this functional magnetic resonance imaging (fMRI) study, we investigated whether activation within the amygdala, a brain region closely linked to the processing of threat, may also function as a predictor of RTs, similar to trait anxiety scores. After threat conditioning by means of aversive electric shocks, 45 participants performed a choice RT task during alternating 30 s blocks in the presence of the threat conditioned stimulus [CS+] or of the safe control stimulus [CS-]. Trait anxiety was assessed with the State-Trait Anxiety Inventory and participants were median split into a high- and a low-anxiety subgroup. We tested three hypotheses: (1) RTs will be faster during the exposure to threat compared to the safe condition in individuals with high trait anxiety. (2) The amygdala fMRI signal will be higher in the threat condition compared to the safe condition. (3) Amygdala fMRI signal prior to a RT trial will be correlated with the corresponding RT. We found that, the high-anxious subgroup showed faster responses in the threat condition compared to the safe condition, while the low-anxious subgroup showed no significant difference in RTs in the threat condition compared to the safe condition. Though the fMRI analysis did not reveal an effect of condition on amygdala activity, we found a trial-by-trial correlation between blood-oxygen-level-dependent signal within the right amygdala prior to the CRT task and the subsequent RT. Taken together, the results of this study showed that exposure to threat modulates task performance. This modulation is influenced by personality trait. Additionally and most importantly, activation in the amygdala predicts behavior in a simple task that is performed during the exposure to threat. This finding is in line with “attentional capture by threat”—a model that includes the amygdala as a key brain region for the process that causes the response slowing.
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Monsifrot, Jonathan. "Modélisation de signaux électromyographiques par des processus de renouvellement - Filtre bayésien pour l'estimation séquentielle de paramètres à destination de la commande d'une prothèse d'avant-bras." Phd thesis, Université de Nantes, 2013. http://tel.archives-ouvertes.fr/tel-00921011.
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Nous traitons des signaux électromyographiques intramusculaires (signaux iEMG) relevés dans les muscles de l'avant-bras. Les signaux iEMG représentent une image de la commande du système nerveux central vers les muscles. Ils se composent d'une superposition de trains d'ondelettes, chaque ondelette code un groupe de fibres musculaires et son taux de mise à feu code l'effort produit par ce groupe. L'objectif est d'extraire de façon séquentielle des informations du signal iEMG. Nous espérons que ces informations se révèleront utiles pour la commande d'une prothèse d'avant-bras. En premier lieu, nous modélisons un train d'impulsions comme une chaîne de Markov et nous discutons des lois pouvant caractériser le temps entre deux impulsions. La loi de Weibull discrète a retenu notre attention. Nous avons mis en place une méthode d'estimation en ligne de ses paramètres. En second lieu, nous modélisons le signal iEMG par un modèle de Markov caché s'appuyant sur le modèle de train d'impulsions ci-dessus. La mise en place d'un filtre bayésien nous permet de propager séquentiellement une estimation bayésienne des paramètres du modèle de Markov caché, en particulier la forme des ondelettes et leur taux de mise à feu. Nous proposons finalement une méthode d'estimation du nombre de trains d'ondelettes, un paramètre discret du modèle. Nous validons les méthodes et algorithmes proposés sur des signaux simulés et des signaux iEMG.
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Henry, Mathilde. "Rôle de la signalisation des enképhalines par les récepteurs opioïdergiques delta dans la résilience au stress chronique." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/35776.
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La survie d'un individu repose essentiellement sur sa capacité d’adaptation à des conditions de vie en constante évolution. Il existe une grande variabilité entre les individus concernant leur réponse au stress chronique, définissant le concept de résilience. Il s’agit d’un mécanisme d'adaptation actif correspondant à la capacité d'un individu à éviter les conséquences négatives sociales, psychologiques et biologiques d'un stress extrême, qui compromettraient son bien-être psychologique ou physique. Le phénomène est complexe et fait intervenir de nombreuses structures cérébrales et de nombreux neurotransmetteurs. Parmi les systèmes neuropeptidergiques, les opioïdes endogènes, comme les enképhalines (ENKs), seraient des cibles potentiellement impliquées dans ces variations naturelles et pourraient ainsi, être un élément déterminant de la capacité d'adaptation individuelle, au cours de l'exposition au stress chronique. Dans une précédente étude de l’équipe du Dr Guy Drolet, il avait été démontré que les niveaux d'expression de l'ARNm des ENKs étaient diminués dans le noyau basolatéral de l’amygdale (BLA) chez les rats vulnérables après un stress chronique de défaite sociale (SCDS). De plus, l’inhibition des ENKs dans la BLA permettait de reproduire un phénotype de vulnérabilité chez le rat, démontrant ainsi le rôle prépondérant de la circuiterie des ENKs dans le développement de la résilience. Cette thèse a pour objectif principal de comprendre la contribution dans la résilience au stress chronique du circuit des ENKs via les récepteurs opioïdergiques Delta (DOPr), tant au niveau neuroanatomique que fonctionnel. Nous avons, tout d’abord, examiné par hybridation in situ, les niveaux d’expression des ENKs dans la BLA chez la souris après un SCDS : comme chez le rat, les souris vulnérables présentaient une diminution de l’ARNm des ENKs dans la BLA par rapport aux animaux résilients et contrôles. Ce résultat confirme une conservation entre les rongeurs concernant l’implication des ENKs dans la résilience. Par la suite, nous avons évalué les niveaux d’expression de DOPr dans les structures cibles de la BLA. Nous avons spécifiquement ciblé l’hippocampe qui entretient un dialogue privilégié avec l’amygdale dans la réponse au stress et dans lequel, DOPr est fortement exprimé. L’expression de l’ARNm de DOPr était réduite dans la région CA1 de l'hippocampe ventral (CA1-vHPC) chez les souris vulnérables tandis que le niveau était maintenu chez les animaux résilients comme chez les témoins. Afin de disséquer l’importance de la signalisation DOPr dans le développement de la résilience, une activation pharmacologique a été effectuée : l’administration d’un agoniste de DOPr, le SNC80, dans la circulation systémique, a augmenté la proportion de souris résilientes après le SCDS. Dans un second temps, nous avons fait l’hypothèse que le maintien du niveau d’expression de DOPr au niveau du CA1-vHPC permettait de maintenir un statut oxydatif contrôlé dans les neurones, conduisant au phénotype de résilience. En effet, le rôle neuroprotecteur de l’activation de DOPr contre les dommages oxydatifs cellulaires (i.e. stress oxydatif, SO) a été démontré dans différents contextes, notamment chez le rat ischémique. Nous avons ainsi observé des marqueurs du SO - comme les neurones « sombres » ou la dilatation du réticulum endoplasmique - par microscopie électronique à transmission (MET) après un SCDS, avec ou sans traitement au SNC80. Nous avons spécifiquement ciblé les neurones excitateurs et inhibiteurs du CA1-vHPC. Nous avons pu mettre en évidence que le SNC80 diminuait la proportion de certains marqueurs du SO, autant chez les animaux résilients que vulnérables, tandis que pour d’autres marqueurs, il restaurait les dommages oxydatifs induits par le SCDS, uniquement chez les vulnérables. Enfin, une étude ultrastructurelle des mitochondries - comme leur nombre et leur taille - par MET, a confirmé ces résultats où le SNC80 restaure les effets délétères du stress uniquement chez les souris vulnérables. Ces résultats ont permis de démontrer que l’activation de la signalisation DOPr est responsable de la résilience en maintenant un statut oxydatif contrôlé dans les neurones excitateurs et inhibiteurs du CA1-vHPC. Pour finir, une étude moléculaire a été effectuée par western blot, dans l’hippocampe total, afin de déterminer la cible moléculaire de DOPr impliquée dans le SO permettant la résilience. Les complexes de la chaîne respiratoire mitochondriale et des enzymes antioxydantes ont été ciblés. L’activation de DOPr a résulté en une diminution de l’expression de certains complexes sans dévoiler la cible moléculaire exacte de DOPr permettant la résilience au stress chronique. Collectivement, ces études proposent un nouveau mécanisme par lequel la signalisation ENK-DOPr permettrait le développement de la résilience au stress chronique en favorisant un état oxydatif contrôlé dans les neurones de l'hippocampe.The survival of an individual is essentially based on his ability to adapt to ever-changing living conditions. There is a great variability among individuals regarding their response to chronic stress, defining the concept of resilience. Resilience is an active coping mechanism corresponding to an individual's ability to avoid the negative social, psychological and biological consequences of extreme stress that would compromise their psychological or physical well-being. The phenomenon is complex and recruits many brain structures and several neurotransmitters. Among the neuropeptidergic systems, endogenous opioids, such as enkephalins (ENKs), could be potential targets involved in the occurrence of these natural variations and could thus be a crucial determinant of an individual’s capacity to adapt to chronic stress. In a previous study by Dr Guy Drolet's team, ENK mRNA expression levels were shown to be decreased in the nucleus of basolateral amygdala (BLA) in vulnerable rats after chronic social defeat stress (CSDS). In addition, the inhibition of ENKs in the BLA reproduced this vulnerability phenotype in rats, thus demonstrating the preponderant role of the ENK circuitry in the development of resilience. The main objective of this thesis was to investigate the contribution of the ENKs circuit via the Delta opioid receptors (DOPr) in the chronic stress resilience, both at the neuroanatomical and functional levels. We first examined, by in situ hybridization, the expression levels of ENKs in BLA in mice after CSDS: as in rats, susceptible mice showed a decrease in ENK mRNA in BLA compared to resilient and controls animals. This result confirmed the implication of the ENKs in resilience in rodents. Subsequently, we evaluated the expression levels of DOPr in the target structures of the BLA. We specifically targeted the hippocampus, which maintains a privileged dialogue with the amygdala in the response to stress and in which DOPr is strongly expressed. DOPr mRNA expression was reduced in the ventral hippocampal CA1 region (CA1-vHPC) in vulnerable mice while the level was preserved in both resilient and control animals. In order to dissect the importance of DOPr signaling in the development of resilience, pharmacological activation was performed: the administration of a DOPr agonist, SNC80, into the systemic circulation, increased the proportion of resilient mice after the CSDS. In a second step, we hypothesized that the maintenance of DOPr mRNA expression in CA1-vHPC allowed the preservation of a controlled oxidative status in neurons, leading to the phenotype of resilience. Indeed, the neuroprotective role of DOPr activation against cellular oxidative damages (i.e. oxidative stress, OS) was demonstrated in different contexts, particularly in ischemic rats. Thus, we observed markers of OS - such as dark neurons and endoplasmic reticulum dilation - by transmission electron microscopy (TEM) after CSDS, with or without SNC80 treatment. We specifically targeted excitatory and inhibitory neurons of CA1-vHPC. We were able to demonstrate that the SNC80 decreased the proportion of some OS markers in both resilient and vulnerable animals, while for other markers, it restored CSDS-induced oxidative damages only in vulnerable mice. Finally, an ultrastructural study of mitochondria by TEM, confirmed these results where the SNC80 restored the deleterious effects of stress only in vulnerable mice. These results demonstrated that activation of DOPr signaling is responsible for resilience by the preservation of a controlled oxidative status in excitatory and inhibitory neurons of CA1- vHPC. Finally, a molecular study was performed by western blot, in the total hippocampus, to determine the molecular target of DOPr involved in OS, allowing stress resilience. Complexes of the mitochondrial respiratory chain and antioxidant enzymes were measured. The activation of DOPr showed a decrease in the expression of certain complexes without revealing the exact molecular target of DOPr allowing resilience to chronic stress. Overall, these studies propose a novel mechanism by which ENK-DOPr signaling promotes resilience to chronic stress by enhancing a controlled oxidative status in hippocampal neurons.
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Sommer, Andrew Patrick. "VIBRATION-BASED HEALTH MONITORING OF MULTIPLE-STAGE GEAR TRAIN AND DIFFERENTIAL PLANETARY TRANSMISSION INVOLVING TEETH DAMAGE AND BACKLASH NONLINEARITY." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/631.
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The objective of this thesis is to develop vibration-based fault detection strategies for on-line condition monitoring of gear transmission systems. The study divides the thesis into three sections. First of all, the local stresses created by a root fatigue crack on a pinion spur gear are analyzed using a quasi-static finite element model and non-linear contact mechanics simulation. Backlash between gear teeth which is essential to provide better lubrication on tooth surfaces and to eliminate interference is included as a defect and a necessary part of transmission design. The second section is dedicated to fixed axis power trains. Torsional vibration is shown to cause teeth separation and double-sided impacts in unloaded and lightly loaded gearing drives. The transient and steady-state dynamic loading on teeth within a two stage crank-slider mechanism arising from backlash and geometric manufacturing errors is investigated by utilizing a non-linear multi-body dynamics software model. The multi-body model drastically reduces the computation time required by finite element methods to simulate realistic operation. The gears are considered rigid with elastic contact surfaces defined by a penalty based non-linear contact formulation. The third section examines a practical differential planetary transmission which combines two inputs and one output. Planetary gears with only backlash errors are compared to those containing both backlash and tooth defects under different kinematic and loading conditions. Fast Fourier Transform (FFT) analysis shows the appearance of side band modulations and harmonics of the gear mesh frequency. A joint time-frequency analysis (JTFA) during start-up reveals the unique vibration patterns for fixed axis gear train and differential planetary gear, respectively, when the contact forces increase during acceleration.
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Ortiz-Rosario, Alexis. "Improved Methodologies for the Simultanoeus Study of Two Motor Systems: Reticulospinal and Corticospinal Cooperation and Competition for Motor Control." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468886309.
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Labat, Christian. "Algorithmes d'optimisation de critères pénalisés pour la restauration d'images : application à la déconvolution de trains d'impulsions en imagerie ultrasonore." Phd thesis, Ecole centrale de nantes - ECN, 2006. http://tel.archives-ouvertes.fr/tel-00132861.
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La solution de nombreux problèmes de restauration et de reconstruction d'images se ramène à celle de la minimisation d'un critère pénalisé qui prend en compte conjointement les observations et les informations préalables. Ce travail de thèse s'intéresse à la minimisation des critères pénalisés préservant les discontinuités des images. Nous discutons des aspects algorithmiques dans le cas de problèmes de grande taille. Il est possible de tirer parti de la structure des critères pénalisés pour la mise en oeuvre algorithmique du problème de minimisation. Ainsi, des algorithmes d'optimisation semi-quadratiques (SQ) convergents exploitant la forme analytique des critères pénalisés ont été utilisés. Cependant, ces algorithmes SQ sont généralement lourds à manipuler pour les problèmes de grande taille. L'utilisation de versions approchées des algorithmes SQ a alors été proposée. On peut également envisager d'employer des algorithmes du gradient conjugué non linéaire GCNL+SQ1D utilisant une approche SQ scalaire pour la recherche du pas. En revanche, plusieurs questions liées à la convergence de ces différentes structures algorithmiques sont restées sans réponses jusqu'à présent. Nos contributions consistent à:- Démontrer la convergence des algorithmes SQ approchés et GCNL+SQ1D.
- Etablir des liens forts entre les algorithmes SQ approchés et GCNL+SQ1D.
- Illustrer expérimentalement en déconvolution d'images le fait que les algorithmes SQ approchés et GCNL+SQ1D sont préférables aux algorithmes SQ exacts.
- Appliquer l'approche pénalisée à un problème de déconvolution d'images en contrôle non destructif par ultrasons.
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Russon, Ryan K. "Computerized Measurement of Psychological Vital Signs in a Clinical Setting." [Tampa, Fla. : s.n.], 2003. http://purl.fcla.edu/fcla/etd/SFE0000097.
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Aubagnac, Stéphanie. "Identification et caractérisation fonctionnelle de gènes de prédisposition à la persistance virale et aux signes cliniques de la maladie démyélinisante induite par le virus de Theiler." Paris 7, 2001. http://www.theses.fr/2001PA077250.
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Saideh, Michel. "Contributions on radio access techniques for future railway communications system." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I092.
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Avec l’automatisation croissante des fonctions de contrôle commande dans le domaine ferroviaire, on assiste aujourd’hui à une augmentation drastique des échanges d’information. Ces échanges sont cruciaux pour le déploiement du train autonome, la réduction des coûts d'exploitation et de maintenance, l’amélioration de la sécurité. En même temps, de nombreux nouveaux services d’information et de divertissement s’appuyant sur des systèmes de communication sont proposés aux passagers. Pourtant, il n’y a pas aujourd’hui de technologie unique qui puisse satisfaire tous les besoins exigeants en termes de performances. En conséquence, différents projets de recherche industrielle et académique sont en cours aux niveaux européen et international pour développer le système de communication mobile ferroviaire de demain (ou Future Railway Mobile Communication Système – FRMCS). Ce système s’appuiera sur la technologie IP et sera adaptatif, agnostique à la technologie radio et résilient aux évolutions technologiques. En outre, il devra offrir des débits de données élevés, une faible latence, une large bande passante et une utilisation efficace du spectre. Le FRMCS devra être en mesure de choisir en temps réel entre différentes technologies d’accès radio disponibles en fonction des besoins des applications et de l’environnement ferroviaire. Parmi les technologies d’accès disponibles, on peut citer le Wi-Fi, le LTE, les satellites et le standard 5G NR en cours de développement. Ainsi, les contributions de cette thèse de doctorat s’inscrivent dans le cadre du développement d’un système de communication adaptatif (ACS- Adaptable Communication System) pour le ferroviaire en considérant des technologies de pointe du futur standard 5G NR et au-delà. Différentes technologies clef ont récemment été proposées dans le cadre de la standardisation 5G et au-delà. Parmi celles-ci, les techniques d'accès radio jouent un rôle majeur sur les métriques clés, telles que l'utilisation efficace du spectre disponible, les débits de données élevés et la complexité du système émetteur-récepteur. Une des évolutions technologiques majeure dans ce domaine consiste en l’introduction de différentes techniques de modulation multi-porteuses (MCM- Multi-Carrier Modulation) et des techniques d’accès multiple non orthogonales (NOMA- Non-Orthogonal Multiple Access).Dans ce mémoire de thèse de doctorat, nous commençons par étudier les techniques MCM dans le contexte des défis posés par la grande vitesse ferroviaire. Une évaluation des performances est réalisée en considérant différents systèmes multi porteuses dans différents scénarios. La forme d'ondes FBMC (Filtered Bank Multi-Carrier) offre une grande robustesse dans des scénarios de forte mobilité tout en exploitant efficacement le spectre disponible. Cependant, les avantages de la modulation FBMC s'accompagnent d'interférences intrinsèques supplémentaires qui remettent en question les techniques de conception des émetteurs-récepteurs traditionnels. Ainsi, nous proposons différentes contributions qui concernent les techniques d’estimation et d’égalisation du canal pour la forme d’onde FBMC. Les contributions visent à augmenter les performances finales au prix d’une complexité supplémentaire négligeable si on compare à la littérature existanteNowadays, a huge amount of data exchanges is needed in the railway system. This is particularly to support autonomous train, reduce operation and maintenance costs, increase safety and security. In the same time, many new services are offered to passengers. There is no unique technology that can satisfy all these needs. Consequently, different industrial and academical research projects are on-going at European and International levels to develop the Future Railway Mobile Communications System (FRMCS). FRMCS will be IP-based, adaptable, agnostic to radio technology and resilient to technological evolutions. In addition, it should support high data rate, low latency, large bandwidth, and efficient spectrum utilization. The FRMCS is expected to be able to choose in real time between different available radio access technologies in function of applications needs and the surrounding railway environment. Among these technologies, we can mention the Wi-Fi, LTE, satellites and the 5G NR standard in development. Thus, the contributions of this PhD thesis are part of the development of an Adaptable Communication System (ACS) for the railway by considering cutting-edge technologies of the future 5G NR system and beyond. Different key enabling technologies have been proposed recently under the umbrella of 5G and Beyond communication systems. Among which, radio access techniques play major role over key metrics, such as the efficient utilization of the available spectrum, the high data rates, and the computational complexity of the transceiver system. One of the major technological evolution in that domain concerns the introduction of different Multi-Carrier Modulation (MCM) and Non-Orthogonal Multiple Access (NOMA) techniques. In this Ph.D thesis, we start by considering the MCM technology in the context of high speed railway. A performance evaluation study is conducted where different MCM schemes are highlighted in different scenarios. The Filtered Bank Multi-Carrier (FBMC) waveform presents high robustness to high mobility scenarios while exploiting the available spectrum efficiently. However, FBMC advantages come with additional built-in interference that challenges traditional transceiver design techniques. Thereby, we propose different contributions that handle the channel estimation and equalization aspects of the FBMC waveform. The contributions aims to assure better performance at the cost of negligible additional complexity compared with the literature
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Bataillon, Jean-Luc. "La métrologie des circuits intégrés par microscopie électronique." Grenoble INPG, 1990. http://www.theses.fr/1990INPG0001.
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Le memoire traite des problemes rencontres lors de l'utilisation de la microscopie electronique a balayage pour effectuer les controles dimensionnels au cours de la fabrication des circuits integres vlsi. L'eventail des techniques de metrologie est presente en preambule de cette etude. Une etude quantitative de la resolution du meb a ete developpee a l'aide des techniques de l'analyse spectrale afin d'evaluer les variations des performances instrumentales en fonction de la tension d'acceleration et du courant de faisceau. Pour connaitre le biais entre la dimension mesuree et la largeur exacte, une nouvelle technique de reconnaissance topographique des traits clives a ete mise au point sur le meb de metrologie. On determine ainsi avec une precision mesurable le profil geometrique des traits. La methode de mesure dimensionnelle retenue est l'estimation par autocorrelation du profil electronique filtre. Cet estimateur est valide sur le plan de la fiabilite et de la repetabilite par une etude experimentale approfondie. La justesse des resultats est assuree grace a la calibration d'une plaquette representative du niveau mesure. Les deux methodes mises en uvre pour determiner les conditions experimentales optimales, la comparaison des mesures de traits isolants et conducteurs, et la minimisation de la dispersion des courbes de calibration, s'accordent sur le choix des tensions d'acceleration inferieures a 1,2 kvolt
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Eskiizmirliler, Tevfik Selim. "Modélisation de la fusion des informations sensori-motrices dans les voies cérébelleuses : application à la prédiction des cinétoses dans les trains pendulaires et au contrôle d'un actionneur mû par des muscles pneumatiques." Paris, ENST, 2000. http://www.theses.fr/2000ENST0047.
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Tahri, Tarik. "Systèmes radars coopératifs multimodes pour la détection, l'identification des obstacles sur les voies, la localisation et la transmission de données trains-infrastructures." Thesis, Valenciennes, 2014. http://www.theses.fr/2014VALE0024/document.
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Le domaine des télécommunications ferroviaires est en perpétuelle évolution, ses axes d’investigation sont principalement motivés par un besoin toujours grandissant en termes de débit de données, qualité de transmission et fiabilité de localisation, mais restent freinés par un environnement fréquentiel de plus en plus encombré. Dans ce contexte, la conception d’un système qui assure à la fois, les besoins de localisation, d’identification des obstacles, et de communication, semble primordiale. Aussi, la technologie ultra large bande s’avère très prometteuse comme technologie de base pour ce système. Dans ce travail de thèse, un système radar coopératif pour la localisation, la détection d’obstacles, l’identification d’obstacles et la communication basé sur la technologie ULB, est proposé. Dans ce cadre, différentes techniques de multiplexage basées sur le principe de plusieurs techniques de modulation et d’accès multiple telles que la PPM, l’OAM, la 2πM, et la DS-CDMA ont été développées. Ces techniques ont pour buts, de séparer les signaux de communication et les signaux de localisation, ainsi que d’augmenter le débit des transmissions de données en augmentant le nombre des paramètres véhiculant l’information à envoyer. Des études théoriques alliées à des simulations ont été réalisées, afin de les comparer en termes de taux d’erreur binaire et de débit. Les résultats théoriques et de simulations du système proposé ont été validés par des expérimentations menées dans un environnement réelTelecommunication in railway land is in perpetual evolution, its investigation axes are mainly motivated by a growing need in term of data rates, quality of transmission, accuracy and reliability of the localization, but it remains slowed by a frequentiel environment, which is increasingly crowded. In this context, the design of a system that ensure in same time, localization, obstacles recognition and communication, seems a very critical. In this thesis, to design such a sensor, we propose the use of so-called spectral diversity techniques also found under the name of Ultra Wideband radio (UWB). To separate localization signal and communication signal and to increase communication data rate, several multiplexing techniques based on the principle of multiple modulation techniques and multiple access such as PPM, the OAM, the 2πM, and DS-CDMA have been developed. Theoretical studies combined with simulations were performed to evaluate and compare these techniques in term of binary error rate and data rate communication. Theoretical results and simulations of the proposed system have been validated by experiments conducted in a real environment
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Hawari, Haitham M. "Minimising track degradation through managing vehicle/track interaction." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16366/.
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The rate at which a railway track deteriorates depends on the response of the track under different static and repeated dynamic forces. These wheel/rail forces lead to imperfections in the rail surface and deviation in track geometry alignment. The wheel/rail forces are dependent upon the quality of maintenance of the characteristics of both train and track. If train components such as wheelsets and suspensions are maintained to a high standard, less dynamic forces are generated at the wheel/rail interface and less damage is caused over time. Therefore, the amount and cost of maintenance of track are reduced. However, there is little known about how the characteristics of train components affect time-dependent track degradation. Track degradation through deviation of track from its ideal position has the most effect on maintenance costs. Therefore, the present research aims to investigate this track degradation and improve understanding of the effects of train characteristics (such as train mass and speed, suspension stiffness and damping) on railway tracks. The research is conducted by looking into the relationship between wheel/rail forces and track degradation on one hand and between wheel/rail forces and train characteristics on the other hand, with the objective of assisting in managing vehicle/track interaction in order to minimise track degradation. This aim is achieved by investigating the above two relationships to attain the desired relationship between track degradation and train characteristics. The research focuses on wheel/rail vertical forces (both amplitudes and frequencies), vertical track alignment (longitudinal vertical profile), and rail head defects. The study started by collecting wheel/rail vertical forces data in addition to data on vertical track degradation under sustained traffic loads on a heavy haul railway section of track in Central Queensland. Also, five years of degradation and maintenance history data were collected on three other test sections of railway track under variety of traffic conditions and loads in Central Queensland. There were four main analyses of this data employed to probe the study. The first analysis was performed by examining the track degradation history data. The standard deviation method was used in this first analysis to acquire the rate of deterioration in terms of its relationship to track profile (roughness). The second analysis was accomplished by correlating the vertical wheel/rail forces to both vertical track profile and rail roughness using signal processing principles and a function know as coherence. The third analysis was carried out by using the computer simulation software NUCARS to obtain the link between wheel/rail forces and the deterioration of the vertical track profile. The fourth analysis was achieved by combining the results obtained from the above three analyses to acquire the rate of track deterioration in terms of its relationship to varying train characteristics. The first analysis mentioned above quantified the relationship between the level of roughness of the track and rate at which that roughness deteriorated. An important outcome of this relationship is that there is a threshold of roughness below which track deterioration is minimal. The track maintenance planners can now use that threshold for cost effective targeting of tamping activities. The correlation study between track roughness and wheel/rail forces using the coherence function found, surprisingly, that the overall deterioration of the track roughness, in the absence of frequencies of forces above 30 Hz, is due to the so-called quasi-static lower frequency oscillations of dynamic forces. This conclusion together with the relationship between vehicle characteristics and track forces, established in the analyses above, has significant implications for the design of wagon bogies and for charges track owners might levy on trains using their tracks. This research is part of a larger Rail CRC project 11/4 called 'Enhancing the Optimisation of Maintenance/Renewal' being carried out in the School of Urban Development in Queensland University of Technology.
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Kakuschke, Chris. "Entwicklung alternativer Auswerteverfahren für Mikrowellendopplersignale bei der Geschwindigkeitsbestimmung im Bahnverkehr." Doctoral thesis, Universitätsbibliothek Chemnitz, 2004. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200400877.
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To measure the speed of a vehicle, the revolution of a wheel or a rigid axle is traditionally used. Therefore non corrigible systematic errors occur which are caused by slip, spin and by the change of wheel diameter due to fretting. Train control and traction systems require new robust as well as precise methods of speed measurement. Because of their physical properties, Doppler-radar-sensors attached to the vehicle and measuring ground speed are first choice for this range of applications. Currently used sensors cannot fulfil the high demands under all operating conditions, because they are unable to completely compensate the various interferences and systematic deviations. This is the starting point of this dissertation. Two independent diverse methods with optimised reliability and accuracy must be used to meet all requirements. Limited resources of the embedded digital signal processor system under real-time conditions have to be taken into account. According to the boundary conditions, the introductory chapters critically discuss the frequency analysis methods currently used and describe starting points for further development. This leads to the design of a new, robust, wide-band spectral analysis which combines techniques of the dyadic wavelet transformation with the fast Fourier transformation. At the same time a new frame procedure and general model for the estimation of motion parameters is developed which features short delays. The disadvantages of the block-based discrete spectral analysis applied over continuous approaches are extensively compensated. The block structure of spectral data enables the selective use of new knowledge-based spectral filters for the compensation of the remaining intense interferences which are typical of this kind of applicationDie Fahrzeuggeschwindigkeitsmessung über die Drehzahl eines Rades weist in Schlupf- und Schleuderzuständen erhebliche systematische Abweichungen auf. Deshalb erfordern Zugbeeinflussungs- und Antriebssysteme neue gleichzeitig robuste und präzise Geschwindigkeitsmessmethoden. Die Mikrowellensensorik unter Nutzung des Dopplereffekts zwischen Fahrzeug und Gleisbett wird wegen ihrer physikalischen Eigenschaften für dieses Einsatzgebiet favorisiert. Bisherige Sensorapplikationen erfüllen aber die hohen Ansprüche nicht in allen Betriebszuständen. Hier setzt die in dieser Arbeit beschriebene Sensorentwicklung auf. Zwei getrennt hergeleitete und nach Zuverlässigkeit und Genauigkeit optimierte neue Verfahren können bei gleichzeitiger Anwendung die gestellten Anforderungen erfüllen. Dabei müssen auch die beschränkten Ressourcen des eingebetteten digitalen Signalverarbeitungssystems unter Echtzeitbedingungen berücksichtigt werden. Entsprechend dieser Randbedingungen findet einleitend eine kritische Betrachtung bestehender Frequenzanalysemethoden statt und Ansätze für die Weiterentwicklung werden herausgearbeitet. Einerseits führt dies zur Konstruktion einer neuen störunempfindlichen Weitbereichsspektralzerlegung, welche Ansätze der dyadischen Wavelettransformation mit der Diskreten Fourier-Transformation verbindet. Andererseits wird ein neues Rahmenverfahren für die verzögerungsarme Schätzung der Bewegungsparameter des Fahrzeuges aufgrund seines physikalischen Bewegungsmodells hergeleitet und mit einem hochgenauen Frequenzauswerteverfahren kombiniert. Beide Verfahren basieren auf blockweisen diskreten Spektralzerlegungen, deren prinzipielle Nachteile gegenüber kontinuierlichen Ansätzen weitgehend kompensiert werden können. Durch die Blockorganisation lassen sich neuartige wissensbasierte Spektralfilter selektiv zur Unterdrückung starker bahnanwendungstypischer Störeinflüsse einsetzen
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Svoboda, Lukáš. "Monitorování dynamických soustav s využitím piezoelektrických senzorů vibrací." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-432742.
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The aim of this diploma thesis is to describe localization and calculation load identification of dynamic systems using piezoelectric sensors. Finding methods, which would allow us to evaluate loads on simple systems is the key to their application in the structural health monitoring of more complex systems. A theory necessary for understanding and application in aerospace, civil engineering, automobile industry, and train traffic of presented methods is given in the first part of the thesis. In these applications, the methods of wave propagation and different types of neural network methods are used to evaluate load identification. It is possible to evaluate loads by using a time reverse method, a method based on signal deconvolution, and a method based on a voltage amplitude ratio of the piezoelectric sensor. In the next part, the methods are described, the suitable place for gluing of a sensor, and the number of sensors for using method is given. These methods were verified and compared to a simple experimental system. In the following part, the model of the piezoelectric sensor is presented. It is possible to use the model for calculating voltage output from the strain. For methods verification, the problem of train passage in a specific place of the railway is chosen. The speed of the train and its load on the railway was calculated by using these methods.
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Snuffer, Moira Calligan. "A Study of the Watershed Management in the Headwaters of the Hocking River: Environmental Communication in the City." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1597266102553851.
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Pai, Hong Jin. "Efeitos da acupuntura sobre os pacientes com asma leve e moderada persistentes: um estudo randomizado, controlado e cruzado." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/5/5144/tde-05052014-121907/.
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Introdução: Este estudo foi realizado com o intuito de avaliar efeitos da acupuntura sobre os pacientes com asma leve e moderada persistentes com o uso de beta-2 agonista ou corticoide inalatório. Métodos e casuística: Trata-se de um estudo prospectivo, duplo-cego, randomizado e cruzado com dois braços. Os 74 pacientes com diagnóstico de asma leve/moderada, de acordo com a classificação de GINA 2002/2003, foram divididos em dois grupos, sendo 31 do Grupo I, e 43 do Grupo II inicialmente. Foram realizadas consultas médicas e exames que incluíram espirometria, citologia de escarro induzido, NO expirado, preenchimento de escala de sintoma, questionários de qualidade de vida de asma e de SF 36, e realização de peak-flow, dependendo da Fase do protocolo. A Fase I constituiu-se dos exames pré-intervenção. Na Fase II, foram realizadas 10 sessões de Acupuntura Real no Grupo I e 10 sessões de Acupuntura Sham no Grupo II, na Fase III, houve 4 semana de washout, na Fase IV, houve a troca de técnicas de acupuntura, sendo uma sessão por semana e, na Fase V, realização dos exames. Resultados: Não há diferença nos critérios de avaliação no pré-tratamento entre dois grupos, com exceção de maior celularidade inflamatória no Grupo II. No entanto, houve uma redução significativa de eosinófilos (p = 0,035) e neutrófilos (p = 0,047), e aumento de macrófagos (p = 0,001), melhora da medida de volume do peak-flow (p = 0,01) na fase IV do Grupo II. No Grupo I, na avaliação de escala de sintomas diária, havia menor uso de medicação de resgate (p = 0,043) na Fase II, e, depois de receber a Acupuntura Sham na Fase IV, havia menos tosse (p = 0,007), menos chiado (p = 0,037), menos dispneia (p < 0,001) e menor uso de medicação de resgate (p < 0,001). No Grupo II, após receber o tratamento com a Acupuntura Sham na Fase II, houve diminuição de tosse (p = 0,037), de chiado (p = 0,013) e de dispneia (p = 0,014), e, na Fase IV, havia menos tosse (p = 0,040), sibilos (p = 0,012), dispneia (p < 0,001) e menos despertares noturnos (p = 0,009). Nos questionários de qualidade de vida de asma e de SF 36, foram encontrados alguns aspectos de melhora significantes na Acupuntura Sham dos dois grupos em relação à Fase I, mas os resultados da Acupuntura Real tiveram maiores índices de melhora em relação aos resultados da Acupuntura Sham nos dois grupos. Mas não há diferença significativa entre os dois na qualidade de vida de SF 36. Entretanto, não houve alteração de avaliação de espirometria e de óxido nítrico expirado. Conclusão: Este estudo demonstrou que o uso de Acupuntura Real num grupo de pacientes com a celularidade mais inflamatória teve melhor resultados de sintomas diários, tais como dispneia e despertar noturno, de medida de volume de peak-flow matutina, e de avaliação de qualidade de vida em asma e SF36, além da diminuição quantitativa de neutrófilos e de eosinófilos, com aumento de macrófagos, que justificam os efeitos anti-inflamatórios e imunitários. A acupuntura é uma terapia segura, não havendo nenhum efeito colateral observado neste projeto que possa interferir com a vida cotidiana e pode ser de grande auxílio no alívio de sintomas, com melhora de qualidade de vida e, possivelmente, pode ter uma ação na modulação do processo inflamatório de vias aéreasIntroduction: This survey has been conducted in order to evaluate the effects of acupuncture in patients with persistent mild and moderate asthma (according to GINA criteria 2003), using beta agonist and/or inhaled glucocorticoid. Methods and patients: This is a prospective, double blinded, randomized and cross-over study with two branches: 74 patients diagnosed with mild and moderate asthma were divided into two groups: Group I with 31, initiating with real acupuncture and Group II, starting with sham acupuncture. Medical interview and laboratory tests including spirometry, induced sputum citology, exhaled NO measurement, quality of life questionnaire (SF-36 and QQL), besides, daily symptom scores and measurement of peak-flow were performed, in the beginning of the study, and in the end of each phase of treatment. Phase I: laboratory tests and other qualitative measurements. There were 10 real acupuncture weekly sessions to Group I and 10 sham acupuncture sessions to Group II in Phase II. On the other hand, in the Phase IV, there was an exchange between Group I and Group II, which was receiving real acupuncture started to receive sham, and vice-versa, the number of sessions remained the same (10 weekly sessions). Phase III, during the interval between Phase II and Phase IV, there was an interval of 4 weeks of washout. Phase V: laboratory tests and other qualitative measurements. Results: There was no difference beween both the groups in all criteria of evaluation pré treatment, with only na exception: in the Group II there was large inflammatory cell counts. However, there was a significant reduction in eosinophils (p = 0.035) and neutrophils (p = 0.047), and increase of macrophages (p = 0.001), improved peak-flow measurement in the morning (p = 0.01) in Group II (started with sham) in Phase IV. In Daily Symptons Score, there was a significant reduction in use of rescue medication (p = 0.043) in Group I (real acupuncture) in Phase II and after received sham acupuncture (Phase IV), there were less cough (p = 0.007), less wheezing (p = 0.037), less dyspnea (p < 0.001) e less use of rescue medication (p < 0.001). In Group II, after received sham (Phase II), there were less cough (p = 0.037), less wheezing (p = 0.013) and less dyspnea (p = 0.014). In Phase IV, less cough (p = 0.040), wheezing (p = 0.012), dyspnea (p < 0.001) and less nocturnal awakening (p = 0.009). In the questionnaires of quality of life SF-36 and QQL, several domains were found to be improved after received sham acupuncture in both groups, comparing phase II against phase I, but the results found after received real acupuncture were better than sham in both groups. Although there was no statistic difference between both groups. However, there was no difference in exhaled NO and spirometry measurement. Conclusion: This survey demonstrated that the use of real acupuncture in a group of patients with large inflammatory cells counts could have contributed to reduce symptoms, improve quality of life, improved peak-flow measurement in the morning and reduced inflammatory cells count in induced sputum, therefore, acupuncture is a safe healing techniques, presented no adverse effects observed in this study, and could of great help in treatment of patients with mild and moderate asthma
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Pham, The Anh. "Détection robuste de jonctions et points d'intérêt dans les images et indexation rapide de caractéristiques dans un espace de grande dimension." Thesis, Tours, 2013. http://www.theses.fr/2013TOUR4023/document.
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Les caractéristiques locales sont essentielles dans de nombreux domaines de l’analyse d’images comme la détection et la reconnaissance d’objets, la recherche d’images, etc. Ces dernières années, plusieurs détecteurs dits locaux ont été proposés pour extraire de telles caractéristiques. Ces détecteurs locaux fonctionnent généralement bien pour certaines applications, mais pas pour toutes. Prenons, par exemple, une application de recherche dans une large base d’images. Dans ce cas, un détecteur à base de caractéristiques binaires pourrait être préféré à un autre exploitant des valeurs réelles. En effet, la précision des résultats de recherche pourrait être moins bonne tout en restant raisonnable, mais probablement avec un temps de réponse beaucoup plus court. En général, les détecteurs locaux sont utilisés en combinaison avec une méthode d’indexation. En effet, une méthode d’indexation devient nécessaire dans le cas où les ensembles de points traités sont composés de milliards de points, où chaque point est représenté par un vecteur de caractéristiques de grande dimensionLocal features are of central importance to deal with many different problems in image analysis and understanding including image registration, object detection and recognition, image retrieval, etc. Over the years, many local detectors have been presented to detect such features. Such a local detector usually works well for some particular applications but not all. Taking an application of image retrieval in large database as an example, an efficient method for detecting binary features should be preferred to other real-valued feature detection methods. The reason is easily seen: it is expected to have a reasonable precision of retrieval results but the time response must be as fast as possible. Generally, local features are used in combination with an indexing scheme. This is highly needed for the case where the dataset is composed of billions of data points, each of which is in a high-dimensional feature vector space
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Van, Der Merwe Johannes Hendrik. "Train driver automation strategies to mitigate signals passed at danger on South African railways." Thesis, 2018. https://hdl.handle.net/10539/25972.
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A research project report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfillment of the requirements for the degree of Masters in Engineering.
Date 2018/04/18Train derailments or collisions have the potential to result in catastrophic loss of life and/or destruction of property. Ever higher demands for train density (i.e. trains per hour for a given section of track) as well as the catastrophic results when accidents do occur have given rise to the development of railway signalling systems as mitigation measures (Rolt, 2009; Theeg & Vlasenko (2009b). Signals Passed At Danger (SPADs) refers to when a train driver passes a stop signal without authority and is one of the typical causes of such accidents resulting in significant damages reported within Transnet Freight Rail (TFR) in recent years. Studies have shown human train driver error and violation of signals to be a significant cause of SPAD events. This study investigated the application of train driver automation as a mitigation measure against SPADs within the South African railway environment in general and TFR in particular. The study was qualitative in nature, following a model development methodology and used in-depth, semi-structured interviews with railway signalling engineers for data collection. The primary goal was defined to be the development of a train driver function automation method that could be considered the most appropriate within the TFR operational environment. The study determined the most appropriate method to be that of having a human driver with technical supervision. In this arrangement, the human driver could remain in his conventional role of driving the train but with a technical supervision system superimposed that automatically intervenes if a train driver exceeds his movement authority (e.g. Automatic Train Protection or ATP). This approach mitigates many of the costs imposed by human failure associated with SPAD events, yet retains the value of human flexibility which is especially useful under abnormal circumstances.
MT 2018
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Huang, Kuo-lung, and 黃國隆. "A Study & Design on the Simulation and Control of High Speed Railway Signals and Train Movement." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/27701530166451201564.
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碩士大葉大學
電機工程研究所
88
This thesis describes the application of signals in the traffic system for executing automatic control to provide a safe, comfortable and convenient system through the theory and coordination of signal system and block device. In aspects of blocking theory and automatic train control, two fixed train-passing points will be emphasized in this article to demonstrate the application of moveable automatic block system of which the safe brake distance section is used to controls the traffic of train. Regarding the incoming line control process, including choice of incoming lines, switch shift, inspection of incoming lines, locking, signal release and de-locking of incoming line, the concept of digital logic is used to carry out the analysis and installation. In addition, the railway circuit is also analyzed in this article by using rails as part of the circuit so as to control, directly or indirectly, the circuit system of signals, turnouts or other security devices by the short circuit effect of axle shaft. Finally, PID control system is also employed in this article to simulate the train on the one hand and on the other, the adaptive control system is also applied to simulate the follow-up characteristics of train and its automatic brake reaction under the effect of automatic protection.
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Mao, Chia-Wei, and 茅家瑋. "Novel Pulse Train Generation Method and Signal analysis." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/05173154496851168093.
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碩士國立中山大學
光電工程學系研究所
99
In this thesis we use pulse shaping system to generate pulse train. Using empirical mode decomposition(EMD) and short-time Fourier transform(STFT) to analyze the signal of terahertz radiation. we use pulse shaping system to modulate the amplitude and phase of light which provide for pulse train generation. Compare with other method, first, our method will improve the stability of time delay control. Second this method is easier to control the time delay and number of pulse in the pulse train. In the past, people find the occur time of high frequency by observed the time domain of terahertz radiation directly, but if the occur time near the time of the peak power of terahertz radiation, we can’t find out the occur time of high frequency. Using STFT can find out the relationship between intensity and time, but if the modes in signal have different width of frequency STFT have to use different time window to get the best frequency resolution and time resolution. However the time window with different width will have different frequency resolution, and the relationship between intensity and time will change with different frequency resolution, therefore using different frequency resolution will get different result, so we need a new signal analysis method. To solve this problem we use EMD to decompose different mode in the signal of terahertz radiation into different intrinsic mode function(IMF), and analyze the signal of terahertz by STFT to find the occur time of high frequency of terahertz radiation. Because the modes are separated in to different IMF, we can use STFT with the same time window. We expect this method applied to narrow-band frequency-tunable THz wave generation will be better.
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Parsaei, Hossein. "EMG Signal Decomposition Using Motor Unit Potential Train Validity." Thesis, 2011. http://hdl.handle.net/10012/6299.
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Electromyographic (EMG) signal decomposition is the process of resolving an EMG signal into its component motor unit potential trains (MUPTs). The extracted MUPTs can aid in the diagnosis of neuromuscular disorders and the study of the neural control of movement, but only if they are valid trains. Before using decomposition results and the motor unit potential (MUP) shape and motor unit (MU) firing pattern information related to each active MU for either clinical or research purposes the fact that the extracted MUPTs are valid needs to be confirmed.
The existing MUPT validation methods are either time consuming or related to operator experience and skill. More importantly, they cannot be executed during automatic decomposition of EMG signals to assist with improving decomposition results. To overcome these issues, in this thesis the possibility of developing automatic MUPT validation algorithms has been explored. Several methods based on a combination of feature extraction techniques, cluster validation methods, supervised classification algorithms, and multiple classifier fusion techniques were developed. The developed methods, in general, use either the MU firing pattern or MUP-shape consistency of a MUPT, or both, to estimate its overall validity.
The performance of the developed systems was evaluated using a variety of MUPTs obtained from the decomposition of several simulated and real intramuscular EMG signals. Based on the results achieved, the methods that use only shape or only firing pattern information had higher generalization error than the systems that use both types of information. For the classifiers that use MU firing pattern information of a MUPT to determine its validity, the accuracy for invalid trains decreases as the number of missed-classification errors in trains increases. Likewise, for the methods that use MUP-shape information of a MUPT to determine its validity, the classification accuracy for invalid trains decreases as the within-train similarity of the invalid trains increase. Of the systems that use both shape and firing pattern information, those that separately estimate MU firing pattern validity and MUP-shape validity and then estimate the overall validity of a train by fusing these two indices using trainable fusion methods performed better than the single classifier scheme that estimates MUPT validity using a single classifier, especially for the real data used. Overall, the multi-classifier constructed using trainable logistic regression to aggregate base classifier outputs had the best performance with overall accuracy of 99.4% and 98.8% for simulated and real data, respectively.
The possibility of formulating an algorithm for automated editing MUPTs contaminated with a high number of false-classification errors (FCEs) during decomposition was also investigated. Ultimately, a robust method was developed for this purpose. Using a supervised classifier and MU firing pattern information provided by each MUPT, the developed algorithm first determines whether a given train is contaminated by a high number of FCEs and needs to be edited. For contaminated MUPTs, the method uses both MU firing pattern and MUP shape information to detect MUPs that were erroneously assigned to the train. Evaluation based on simulated and real MU firing patterns, shows that contaminated MUPTs could be detected with 84% and 81% accuracy for simulated and real data, respectively. For a given contaminated MUPT, the algorithm on average correctly classified around 92.1% of the MUPs of the MUPT.
The effectiveness of using the developed MUPT validation systems and the MUPT editing methods during EMG signal decomposition was investigated by integrating these algorithms into a certainty-based EMG signal decomposition algorithm. Overall, the decomposition accuracy for 32 simulated and 30 real EMG signals was improved by 7.5% (from 86.7% to 94.2%) and 3.4% (from 95.7% to 99.1%), respectively. A significant improvement was also achieved in correctly estimating the number of MUPTs represented in a set of detected MUPs. The simulated and real EMG signals used were comprised of 3–11 and 3–15 MUPTs, respectively.
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WANG, TING-FANG, and 王廷芳. "TRAIL transduced reverse signals in T cell activation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/99666307916030568207.
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碩士國立臺灣大學
免疫學研究所
90
TRAIL is a novel member of TNF superfamily molecules, selective induces apoptosis in transformed cell lines, but only with little cytotoxic effect on normal cells. Five TRAIL receptors has been identified and it will transduce signal when engaged with its ligand, TRAIL. Recently studies have found that many TNF superfamily members have ability to transduce reverse signals through ligand itself. Previous studies in our laboratory had proved that TRAIL also can transduce reverse signals after engaging its receptor. According to previous studies in this libratory, it has demonstrated that TRAIL could enhance mouse T cell proliferation after TCR engagement and signal the augmentation of IFNg secretion. To investigate what T cell subsets are involved in TRAIL reverse signals and whether this phenomena also occurs in human PBMC, we isolated both mouse and human CD4+ T cells and CD8+ T cells, stimulated with immobilize DR4-Fc and suboptimal anti-CD3 in vitro. Our results demonstrate that it is CD4+ T cell but not CD8+ T cell responding to TRAIL co-stimulation. Increased production of IFNg is also observed in CD4+ T cells activated with anti-CD3 and DR4. When CD4+ T cells were co-stimulated with TRAIL, there is also increased phosphorylation level of p38 MAP kinase in CD4+ T cells. For further explore the molecules involved in TRAIL reverse signals pathway, we use DR4-Fc to co-immunoprecipitate the possible molecules associated with TRAIL. We were able to detect some possible candidate proteins in Jurkat cells in immunoprecipitation. It still need further characterization to identify the proteins involved in TRAIL reverse signaling. On the other hand, we compared the TRAIL reverse signals with CD28 co-stimulation signals. Our results indicated that CD28 co-stimulation were stronger than TRAIL induced T cell activation at the same level of TCR stimulation in induction of T cell proliferation. To investigate the differences in signal transduction mechanisms between CD28 and TRAIL co-stimulation, we study the tyrosine kinase phosphorylation pattern between T cells activated by CD28 and TRAIL, and we found that there were tyrosine phosphoryaltion induced after TRAIL and CD28 co-stimulation and the phosphorylated tyrosine kinase level were higher in CD28 co-stimulation signals than TRAIL reverse signals. Our results suggest that typrosine kinase may play a role in TRAIL reverse signaling.
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Chen, Chiuan-De, and 陳全德. "TRAIL / TRAIL-R2 as a Potential Termination Signal of Mouse Liver Regeneration." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/76526738233695802997.
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碩士國立陽明大學
醫學生物技術研究所
89
The adult hepatocyte is normally a quiescent and highly differentiated cell. In rodents, experimental partial hepatectomy (PHx) elicits a rapid and precisely controlled series of gene activation, which occurs prior to cellular proliferation. It offers a highly reproducible and precise in vivo system to study the cell cycle regulation of the liver. Transcription activation of various genes including 70 immediate-early genes, growth factors, cytokines, their corresponding receptors and transcription factors has been characterized during liver regeneration. Nonetheless, a comprehensive understanding of the signals for cell cycle regulation during liver regeneration is still lacking. In order to obtain insight into the early regulatory events, our laboratory took a microarray approach in an attempt to obtain a global view of the regulatory network and to identify the early G1 signaling events that were not recognized previously with the conventional methods. At least 10 members of the TNF superfamily were identified from the microarray analysis. Among them, TNF-a, TNF-R1, FasL and Fas have been implicated as important priming and proliferating factors for liver regeneration, while TRAIL, TRAIL-R2, CD40L, BCMA and HVEM were not reported to be involved in the process. Combining RT-PCR, Northern blot and Western blot analyses, we verified the results of microarray hybridization. Both transcription activity and protein profile of TRAIL and TRAIL-R2 were uniquely associated with the late stage (G2-M) of the regenerating liver, suggesting that TRAIL and TRAIL-R2 may serve as a terminating signal. In order to understand how TRAIL and TRAIL-R2 are regulated, we also analyzed the transcription activity and protein profile of IFN-γ, p53 and FLIP. Interestingly, we found that the expressions of IFN-γ,p53 and FLIP and TRAIL-R2 are coordinately regulated. Therefore, it is highly likely in the regenerating liver that TRAIL and TRAIL-R2 are also regulated by IFN-γand p53, respectively as reported in other systems. FLIP was known to suppress the apoptotic signaling downstream of TRAIL /TRAIL-R. Based on the preliminary results, it is difficult to ascertain the biological significance of FLIP in the process of liver regeneration. According to the literature and my preliminary findings, a working hypothesis for TRAIL and TRAIL-R2 as terminating signal was formed. To support the hypothesis, we intended to show a delayed time course of liver regeneration by blocking the signaling pathway of TRAIL and TRAIL-R2. Expression of recombinant soluble TRAIL-ECD and TRAIL-R2/Fc was attempted by using E.coli and Baculovirus systems. Souble TRAIL-R2/Fc was successfully expressed and recovered from the culture supernatant of Sf21 cells. The soluble TRAIL-R2/Fc was also demonstrated its blocking activity in TRAIL-mediated apoptosis in Jurkat cells. With this recombinant protein in hand, one can then demonstrate that TRAIL can elicit apoptosis of hepatocytes taken from late stages of regenerating liver and that soluble TRAIL-R2 can partially suppress the apoptosis observed in the late-stage of regenerating liver by blocking the TRAIL-mediated signaling pathway.
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Lin, Ling-Li, and 林伶俐. "Study of TRAIL Mediated Apoptosis and Reverse Signal." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/48357172095567637494.
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碩士國立臺灣大學
免疫學研究所
88
TRAIL (also called Apo2L), a novel member of the TNF family, induces apoptosis in transformed cell lines of diverse origin. TRAIL mRNA was found in a variety of tissues and cells, but little is known about the expression of TRAIL at the protein level or its physiological function. Recent studies revealed that TRAIL could interact with at least four receptors, TRAIL-R1/DR4, TRAIL-R2/DR5, TRAIL-3/DcR1 and TRAIL-R4/DcR2. Both DR4 and DR5 contain cytoplasmic death domain and mediate apoptosis. In contrast, DcR1 completely lacks a cytoplasmic death domain and exists as a GPI- anchored protein. DcR2 contains a truncated death domain. Neither DcR1 nor DcR2 mediates apoptosis. In this study, we made functional soluble human TRAIL and DR4 recombinant protein from E. coli and Baculovirus expression system. Murine splenic T cells were activated by sub-optimal concentration of anti-CD3 and were incubated with DR4-IgG1Fc recombinant protein to cross-link TRAIL on T cells. We found that cross-linking of TRAIL by sDR4-IgG1Fc recombinant protein induces maximal T cell proliferation and IFN-g production with sub-optimal anti-CD3 stimulation. The increase of T cell proliferation by DR4-IgG1Fc was dose-dependent and can be blocked by soluble TRAIL recombinant protein. In conclusion, our data suggest that TRAIL can itself transduce a reverse signal and which may provide an insight into the biological function for TRAIL.
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Huang, Shih-Chia, and 黃世嘉. "Signal transduction pathways in TRAIL-mediated T cell costimulation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/58564581570796467595.
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博士國立臺灣大學
免疫學研究所
99
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, has been demonstrated to mediate costimulation effect in T cell activation. However, the intra-cellular signaling transduced by TRAIL and the TRAIL costimulatory signaling complementing to TCR stimulation-induced T cell activation remain largely unknown. Aims of this study were to investigate the signaling pathway transduced by TRAIL and the mechanism of TRAIL costimulation to TCR stimulation-induced T cell activation. Our results demonstrated that TRAIL costimulation-induced NF-kappaB activation depended on the PKCtheta-IKK-IkappaB signaling pathway. The PLCgamma1-calcium-NFAT signaling pathway and PI3K-Akt pathway were also activated in TRAIL costimulation. We also demonstrated that TRAIL costimulation amplified TCR proximal kinases signaling. Furthermore, we demonstrated that TRAIL associated with Lck during TRAIL costimulation and the association was required for downstream signaling. DR4-Fc alone stimulation without anti-CD3 mAb also induced the phosphorylation of TCR proximal tyrosine kinases and activated the downstream PI3K-Akt, NFAT and NF-kappaB signaling pathways, but these effects were insufficient for T cell proliferation. Finally, we demonstrated that the TRAIL costimulation induced Lck and PKCtheta recruitment and resulted in lipid rafts reorganization, while these events did not occur in TCR or DR4-Fc alone stimulation. Blocked TRAIL costimulation-induced T cell activation by disruption of lipid rafts indicated the kinases-enriched lipid rafts provided the platform for TRAIL costimulatory signaling integrating into TCR signaling. These results demonstrate that TRAIL costimulation regulates the reorganization of signaling molecules of lipid rafts and then Lck recruitment into lipid rafts integrates the multiple signals from TRAIL and TCR resulting in T cell activation.
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"The Effectiveness of Trail Mitigation and Theory-Grounded Signage in an Economical Approach to Reducing Social Trail Behaviors." Master's thesis, 2018. http://hdl.handle.net/2286/R.I.51687.
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abstract: Trails perform an essential function in protected lands by routing visitors along planned, sustainable surfaces. However, when visitors deviate from official trails in sufficient numbers, it can lead to the creation of social trails. These visitor-created pathways are not sustainably designed and can severely degrade both the stability and appearance of protected areas. A multitude of recreation motivations among visitors and a lack of resources among land management agencies have made the mitigation and closure of social trails a perennial concern. A sustainable, economical strategy that does not require the continual diversion of staff is needed to address social trails. In this study, two techniques that stand out in the research literature for their efficacy and practicality were tested on a social trail closure in South Mountain Park, a high-use, urban-proximate mountain park in Phoenix, AZ. A research design with additive treatments utilizing the site management technique known as trail mitigation, sometimes referred to as brushing in the literature, followed by theory-grounded signage incorporating injunctive-proscriptive wording, an attribution message, and a reasoning message targeting visitor behavioral beliefs, norms, and control was applied and assessed using unobtrusive observation. Both treatments reduced observed off-trail hiking from 75.4% to 0%, though traces of footsteps and attempts to re-open the trail revealed the existence of unobserved “entrenched” users. With entrenched users attempting to reopen the trail, trail mitigation represented an effective but vulnerable approach while the signage represented a long-lasting “hardened” approach that provides an educational message, management’s stance on the closure, and which might put social pressure on the entrenched user(s).Dissertation/Thesis
Masters Thesis Community Resources and Development 2018
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Chen, Ting-Wen. "Assembly processes in soil animal communities: Integrating phylogeny and trait-based approaches." Doctoral thesis, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E372-9.
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Cheng, Yao-Chung, and 鄭燿忠. "Theory and Practice Research on Interpretive Signage Planning and Design: A Case Study on Fencihu-Rueili Historic Trail in Chai-Yi County." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/41695291389259003633.
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碩士中國文化大學
景觀學系碩士班
94
Interpretive signage is the most used interpretive media; it’s also the important agency between human and environment of environmental education system. It could guide tourism to look and observe the environmental phenomenon, to admonish tourist the softy and manage information betimes and to inspire the behavior of environmental protection. It’s an important approach to carry out the environmental sustainable management and eco-tourism. In Taiwan, the resource of the mountain and forest is richness. People could walk into the forest through the trail system. Besides recreation, the trail’s valuations also include environmental experience, landscape and interpretation. So, the trail system needs completely software and hardware facility. At present, interpretive signage only operated by basic theory, that absence distinct process of planning and design. What the interpretive resource is almost subject the designer’s cognizance. Therefore, the research reviewed the theory and method of interpretive signage first and to build the practical process that used on Fencihu-Rueili historic trail in Chai-Yi county. The research join aged person and interpreter of community, administrator and mountain patrol of trail system in the field survey, that conduced to dominate the feature of the trails’ resource and management demand. In the planning phase, the research applied GPS to set the position of interpretive site, and decided the theme, panel’s size, support’s form of interpretive signage. In the design phase, the process included writing content, editing pictures and writing, choosing the material of panels and supports that performed the feature and background of trails. The study is being the critical reference for the scheming and designing steps whereas it is also presents the designing process of the diversified interpreting subjects and outlines the decision flow chart of the design planning for interpretive signage. Furthermore, it is suggested that the study shall be more involved in the aspects of the volume of interpreting words, preferences of reader, color analysis, construction costs, the user’s evaluation and the material development as the future direction.
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DOBNEROVÁ, Karla. "Návrh cyklostezky v okolí obce Kamenný Újezd." Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-54757.
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The main objective of my thesis was to project a design of a concrete chosen section of the cycling trail in the vicinity of the village of Kamenný Újezd, which is located in Southern Bohemia, south-west of České Budějovice. I propose two alternative cycling trails in accordance with the applicable standards, laws and technical conditions. A better alternative in terms of transport, economy, ecology and aesthetics, I elaborated to the phase of documentation for the notification of the construction of road according to Decree 104/1997 Sb.. In the project, I propose a direction solution, vertical solutions, width layout, road construction, earthworks, drainage, equipment and traffic signs. I analyzed property relations in the proposed cycling route and existing bicycle trails in the given locality. I suggested a cycling communication, which is multifunctional, therefore not only used by cyclists but also pedestrians, in-line skaters, and when appropriate, for occasional agricultural transport.