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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improving Open Channel Network Operation Using Gate Control Support Model Developed with ArcGIS Geoprosessing Tools

Eskandari Halvaei, Mostafa 2010 August 1900 (has links)
Many efforts have been conducted for improving the operation and management of open channel networks. Implementing simulation models and software is an effective step in achieving better operation of control structures in open channel networks. The purpose of this study was to develop a tool in ArcGIS for assisting the open channel network managers in operating flow control structures. This model presents a time schedule for gate operation based on the demands at turnouts through the water usage schedule of the network. The developed model was designed to be added as a tool to ArcToolbox in ArcGIS. Any ArcGIS user who has access to ArcView or ArcInfo can add this tool to ArcToolbox. Using ArcGIS Geoprocessing tools, ModelBuilder, Scripting and ArcToolbox tools, the proposed model, "Arc-Canal", was created. Arc-Canal is implementable for irrigation networks that open channel network are digitized in ArcGIS. Simulation is for the gravity flow in open channels without any pump in the network. Calculations are based on steady flow. All hydraulic calculations for water level, gates, and weirs are based on the methods defined in "Open-Channel Hydraulics" (Chow 1959). Most of the available flow simulation models are complicated individual software for which user needs to be trained to install and use it. Also most of these software are not free accessible. Arc-Canal is an easy to use tool that anyone with the knowledge of working with ArcGIS can run it. By adding the tool to ArcToolbox and following the described naming method, and entering the required data, model is ready to run. The developed model is a free access tool. Most of the channels in open channel networks in south Texas have mild bottom slope and flow is steady gravity flow. It is desired that the developed model will be a tool to assist irrigation districts in south Texas.
2

Gate Control Theory and its Application in a Physical Intervention to Reduce Children's Pain during Immunization Injections

Mennuti-Washburn, Jean Eleanor 06 August 2007 (has links)
Vaccinations provide protection against deadly diseases and children are scheduled to receive many immunization injections before the age of six. However, painful procedures, such as immunizations cause negative short- and long-term consequences for children. The Gate Control Theory of Pain suggests that physical interventions may be helpful, but they have not yet been validated as an effective intervention to manage children’s acute pain. This randomized trial examined the effectiveness of the ShotBlocker®, a physical intervention designed to decrease children’s injection pain, in a sample of 89 4- to 12- year-old children receiving immunizations at a pediatric practice. An ANOVA revealed no significant effect of treatment group (Typical Care Control, Placebo, and ShotBlocker®) on any measure of child distress. Clinical and theoretical implications are discussed.
3

Rôle de l'inhibition segmentaire dans le traitement de l'information nociceptive cutanée et méningée dans le complexe trigéminal / Role of segmental inhibition in cutaneous and meningeous nociceptive information treatment in medullary dorsal horn

Melin, Céline 13 December 2011 (has links)
Une réduction de l'inhibition segmentaire contribue vraisemblablement à l'hypersensibilité douloureuse persistante – qui se manifeste par l'hyperalgie, l'allodynie, et la douleur spontanée – au cours d'états douloureux chroniques. L'association fréquente d'une allodynie avec la migraine – une céphalée épisodique – suggère qu'une perte de l'inhibition synaptique contribue aussi à la manifestation de la douleur migraineuse. Cependant, la grande prévalence de la migraine – plus de 10% de la population générale – soulève la question de savoir si le traitement des informations méningées par le réseau neuronal – associant interneurones excitateurs et inhibiteurs – dans le complexe trigéminal, premier relais sur les voies nociceptives de la face et des méninges, est le même que celui des autres informations, par exemple cutanées. Nous avons caractérisé l'effet du blocage pharmacologique des récepteurs à la glycine (GlyR) et des récepteurs GABAA (GABAAR) sur la transmission synaptique entre fibres afférentes primaires, cutanées ou méningées, et neurones de second ordre en enregistrant des potentiels de champ dans le sous-noyau caudal superficiel (Sp5C). Une stimulation électrique transcutanée évoque trois potentiels de champ négatifs dus à l'activation, du plus précoce au plus tardif, de fibres afférentes primaires de type Aβ, Aδ et C. Bloquer les GlyRs et/ou GABAARs segmentaires facilite les potentiels de champ polysynaptiques excitateurs évoqués par l'activation des fibres afférentes primaires de type A et, au contraire, inhibe, ou même abolit, les potentiels de champ C. Bloquer les récepteurs GABAB (GABABR) segmentaires prévient cette suppression. Il est intéressant de noter que bloquer les GABABRs, potentialise aussi les potentiels de champ C en condition controle. Une stimulation électrique méningée évoque deux potentiels de champ négatifs dus à l'activation, du plus précoce au plus tardif, des fibres afférentes primaires de type Aδ et C. Au contraire du potentiel de champ C cutané, le potentiel de champ C méningé est potentialisé après blocage des GlyRs et/ou GABAARs segmentaires. Ces résultats démontrent que le traitement des informations cutanées et méningées par le Sp5C est différent. Seule l'activation des fibres afférentes primaires cutanées de type A inhibe les inputs cutanés de type C vers le Sp5C par l'intermédiaire d'un circuit polysynaptique excitateur, d'interneurones GABAergiques de dernier ordre et de GABABRs présynaptiques. La théorie du "gate control" postule que l'activité des afférences non-nociceptives ferme la porte à la transmission des inputs nociceptifs vers les centres supérieurs. Nos résultats suggèrent que l'état de la porte dépend de l'activité non seulement dans les fibres afférentes primaires de type A mais aussi dans les circuits polysynaptiques excitateurs de la corne dorsale. / Pathological disruption of segmental inhibition is thought to contribute to persistent pain hypersensitivity – including hyperalgesia, allodynia and spontaneous pain – that occurs during chronic pain states. That allodynia is also often associated with migraine – an episodic headache – suggests that a loss of synaptic inhibition is also involved in the manifestation of headache pain. However, the very high prevalence of migraine – more than 10% of the general population – raises the question as to whether processing of meningeous inputs by local neuronal network – consisting of excitatory and inhibitory interneurons – within the trigeminal nucleus, the first relay station for incoming nociceptive signals of the face and meninges, is the same as that of others, for instance cutaneous. We sought to characterize how pharmacological blockade of glycine and GABAA receptors modifies synaptic transmission between either cutaneous or meningeous primary afferent fibers and second order neurons by recording field potentials in the rat superficial medullary dorsal horn (MDH). Transcutaneous electrical stimulation evokes three negative field potentials elicited by, from the earliest to the latest, Aβ-, Aδ- and C-fiber primary afferents. Blocking segmental glycine and/or GABAA receptors strongly facilitates A-fiber-activated polysynaptic excitatory field potentials but, conversely, inhibits, or even abolishes, C-fiber field potentials. Blocking segmental GABAB receptors reverses such suppression. Interestingly, it also potentiates C-fiber field potentials under control conditions. Meningeous electrical stimulation evokes two negative field potentials elicited by, from the earliest to the latest, Aδ- and C-fiber primary afferents. Unlike cutaneous C-fiber field potentials, meningeous ones are facilitated by blocking segmental glycine and/or GABAA receptors. These results demonstrate that MDH processing of cutaneous and meningeous inputs are different. Only activation of cutaneous A-fiber primary afferents inhibits cutaneous C-fiber inputs to the MDH by the way of polysynaptic excitatory pathways, last-order GABAergic interneurons and presynaptic GABAB receptors. In view of the gate control theory postulating that afferent volleys in non-nociceptive afferents close the gate to central transmission of nociceptive inputs, our results suggest that the state of the gate depends on firing activities of both A-fiber primary afferents and polysynaptic excitatory circuits, i.e. the inhibitory tone, within the dorsal horn.
4

Model Based Optimization of Spinal Cord Stimulation

Zhang, Tianhe January 2015 (has links)
<p>Chronic pain is a distressing, prevalent, and expensive condition that is not well understood and difficult to treat. Spinal cord stimulation (SCS) has emerged as a viable means of managing chronic pain when conventional therapies are ineffective, but the efficacy of SCS has improved little since its inception. The mechanisms underlying SCS, in particular the neuronal responses to SCS, are not well understood, and prior efforts to optimize SCS have focused on electrode design and spatial selectivity without considering how the temporal aspects of SCS (stimulation frequency, pattern) may affect neuronal responses to stimulation. The lack of a biophysical basis in prior attempts to optimize therapy may have contributed to the plateau in the clinical efficacy of SCS over time. This dissertation combines computational modeling and in vivo electrophysiological approaches to investigate the effects of SCS on sensory neuron activity in the dorsal horn and uses the insights gained from these experiments to design novel temporal patterns for SCS that may be more effective than conventional therapy.</p><p>To study the mechanisms underlying SCS, we constructed a biophysically-based network model of the dorsal horn circuit consisting of interconnected dorsal horn interneurons and a wide dynamic range (WDR) projection neuron and representations of both local and surround receptive field inhibition. We validated the network model by reproducing cellular and network responses relevant to pain processing including wind-up, A-fiber mediated inhibition, and surround receptive field inhibition. To quantify experimentally the responses of spinal sensory projection neurons to SCS, we recorded the responses of antidromically identified sensory neurons in the lumbar spinal cord during 1-150 Hz SCS in both healthy rats and neuropathic rats following chronic constriction injury (CCI). In a subset of rats, we additionally assessed the impact of GABAergic inhibition on spinal neuron responses to SCS by conducting SCS experiments following the intrathecal administration of bicuculline, a GABAA receptor antagonist, and CGP 35348, a GABAB receptor antagonist. Finally, we used the computational model to design non-regular temporal patterns capable of inhibiting sensory neuron activity more effectively than conventional SCS and at lower equivalent stimulation frequencies than clinical standard 50 Hz SCS, and we experimentally validated model predictions of the improved efficacy of select patterns against conventional SCS.</p><p>Computational modeling revealed that the response of spinal sensory neurons to SCS depends on the SCS frequency; SCS frequencies of 30-100 Hz maximally inhibited the model WDR neuron consistent with clinical reports, while frequencies under 30 Hz and over 100 Hz excited the model WDR neuron. SCS-mediated inhibition was also dependent on GABAergic inhibition in the spinal cord: reducing the influence GABAergic interneurons by weakening their inputs or their connections to the model WDR neuron reduced the range of optimal SCS frequencies and changed the frequency at which SCS had a maximal effect. Experimentally, we observed that the relationship between SCS frequency and projection neuron activity predicted by the Gate Control circuit described a subset of observed SCS-frequency dependent responses but was insufficient to account for the heterogeneous responses measured experimentally. In addition, intrathecal administration of bicuculline, a GABAA receptor antagonist, increased spontaneous and evoked activity in projection neurons, enhanced excitatory responses to SCS, and reduced inhibitory responses to SCS, consistent with model predictions. Finally, computational modeling of dual frequency SCS, implemented by delivering two distinct frequencies simultaneously to distinct fiber populations, revealed frequency pairs that were more effective at inhibiting sensory neuron activity than equivalent conventional SCS and at lower average frequencies than clinically employed 50 Hz SCS. Experimental assessments of the effect of dual frequency SCS on spinal sensory neurons confirmed model predictions of greater efficacy at lower equivalent stimulation frequencies and suggest the use of non-regular temporal patterns as a novel approach to optimizing SCS. The outcomes of this dissertation are an improved understanding of the mechanisms underlying SCS, computational and experimental tools with which to continue the development and improvement of SCS. The insights and knowledge gained from the work described in this dissertation may result in translational applications that significantly improve the therapeutic outcomes of SCS and the quality of life of individuals affected by chronic pain.</p> / Dissertation
5

Differences in Outcomes after Spinal Cord Stimulator Device Placement in the Ohio Board of Workers' Compensation

RABENHORST, ARTHUR E. 22 August 2008 (has links)
No description available.
6

Series-Connection of Silicon Carbide MOSFET Modules using Active Gate-Drivers with dv/dt Control

Raszmann, Emma Barbara 04 December 2019 (has links)
This work investigates the voltage scaling feasibility of several low voltage SiC MOSFET modules operated as a single series-connected switch using active gate control. Both multilevel and two-level topologies are capable of achieving higher blocking voltages in high-power converter applications. Compared to multilevel topologies, two-level switching topologies are of interest due to less complex circuitry, higher density, and simpler control techniques. In this work, to balance the voltage between series-connected MOSFETs, device turn-off speeds are dynamically controlled on active gate-drivers using active gate control. The implementation of the active gate control technique (specifically, turn-off dv/dt control) is described in this thesis. Experimental results of the voltage balancing behavior across eight 1.7 kV rated SiC MOSFET devices in series (6 kV total dc bus voltage) with the selected active dv/dt control scheme are demonstrated. Finally, the voltage balancing performance and switching behavior of series-connected SiC MOSFET devices are discussed. / Master of Science / According to ABB, 40% of the world's power demand is supplied by electrical energy. Specifically, in 2018, the world's electrical demand has grown by 4% since 2010. The growing need for electric energy makes it increasingly essential for systems that can efficiently and reliably convert and control energy levels for various end applications, such as electric motors, electric vehicles, data centers, and renewable energy systems. Power electronics are systems by which electrical energy is converted to different levels of power (voltage and current) depending on the end application. The use of power electronics systems is critical for controlling the flow of electrical energy in all applications of electric energy generation, transmission, and distribution. Advances in power electronics technologies, such as new control techniques and manufacturability of power semiconductor devices, are enabling improvements to the overall performance of electrical energy conversion systems. Power semiconductor devices, which are used as switches or rectifiers in various power electronic converters, are a critical building block of power electronic systems. In order to enable higher output power capability for converter systems, power semiconductor switches are required to sustain higher levels of voltage and current. Wide bandgap semiconductor devices are a particular new category of power semiconductors that have superior material properties compared to traditional devices such as Silicon (Si) Insulated-Gate Bipolar Junction Transistors (IGBTs). In particular, wide bandgap devices such as Silicon Carbide (SiC) Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) have better ruggedness and thermal capabilities. These properties provide wide bandgap semiconductor devices to operate at higher temperatures and switching frequencies, which is beneficial for maximizing the overall efficiency and volume of power electronic converters. This work investigates a method of scaling up voltage in particular for medium-voltage power conversion, which can be applied for a variety of application areas. SiC MOSFET devices are becoming more attractive for utilization in medium-voltage high-power converter systems due to the need to further improve the efficiency and density of these systems. Rather than using individual high voltage rated semiconductor devices, this thesis demonstrates the effectiveness of using several low voltage rated semiconductor devices connected in series in order to operate them as a single switch. Using low voltage devices as a single series-connected switch rather than a using single high voltage switch can lead to achieving a lower total on-state resistance, expectedly maximizing the overall efficiency of converter systems for which the series-connected semiconductor switches would be applied. In particular, this thesis focuses on the implementation of a newer approach of compensating for the natural unbalance in voltage between series-connected devices. An active gate control method is used for monitoring and regulating the switching speed of several devices operated in series in this work. The objective of this thesis is to investigate the feasibility of this method in order to achieve up to 6 kV total dc bus voltage using eight series-connected SiC MOSFET devices.
7

Det gör ont : Läkemedelsfri smärtlindring med stöd av grindteorin ur ett patientperspektiv. / IT HURTS : Non-pharmacological pain relief with support of the gate-control from a patient perspective

Larsson, Britt-Marie, Crantz, Maria January 2013 (has links)
SYFTE: Syftet är att belysa patienternas upplevelse av läkemedelsfri smärtlindring med stöd av grindteorin. DESIGN: Litteraturstudie BAKGRUND: Kunskap om hur patienterna upplever läkemedelsfri smärtbehandling baserad på grindteorin, kan göra det lättare för den enskilda sjuksköterskan att fatta beslut om användande av dessa metoder. URVAL: Vetenskapliga artiklar med empiriska studier på vuxna publicerade mellan åren 2000-2012. METOD: Databassökningar och manuella sökningar RESULTAT: 14 studier med sammanlagt 1771 deltagarevisar att smärtlindringsmetoderna med stöd av grindteorin hade avsedd effekt på smärta. De gav även patienterna lindring vad avser oro och rädsla. Några av studierna tar även upp att patienterna fick en känsla av att själv kunna påverka smärtan. Metoderna som användes var såväl hudstimulerande, som kognitiva. SLUTSATS: Smärtlindring baserad på grindteorin, såväl hudstimulering som kognitiva metoder, är något som sjuksköterskan bör ha kunskap om och använda för att lindra smärta och oro/rädsla. Metoderna är även ett sätt att låta patienten känna sig delaktig, då speciellt de kognitiva metoderna. / PURPOSE: The aim is to illuminate the patients experience of non-pharmacological pain relief with support of the gate-control theory. DESIGN: Literature review/over-view BACKGROUND: Knowledge of how the patients experience non-pharmacological pain treatment based on the gate-control theory can make it easier for the individual nurse to make decisions on the use of these methods. SAMPLE: Scientific studies with empirical studies on adults, published in articles between 2000-2012 METHOD: Database- and manual searches FINDINGS: 14 studies with in total 1771 participants show that the pain relief methods with support of the gate-control theory had the intended effect on pain. They also gave the patients relief with regard to anxiety. Some of the studies also mention that the patients got a feeling of being able to affect the pain themselves. The methods used were skin-stimulating as well as cognitive. CONCLUSIONS: Pain relief based on the gate-control theory, skin-stimulating as well as cognitive methods, is something that the nurse should have knowledge about and use to relieve pain and anxiety. The methods are also a way of letting the patient feel involved, especially the cognitive methods.
8

IoT systém pro domácnost / IoT Home System

Kovařík, Viktor January 2020 (has links)
The aim of this thesis was to learn and summarize basic information about IoT systems, which protocols are used and introduction of Google Home system. The first part of the thesis describes the individual parts of the system --- microcontrollers, sensors, light elements and possible systems for backend. In the implementation part of the thesis was designed a solution for smart home controling using Google Home technology. Based on data from the weather station, the system controls and adjusts the intensity of outdoor lighting and controls the blinds. Furthermore, a control module for gate and garage door control is implemented. The system also takes care of vacuum cleaning in the house using iRobot Roomba vacuum cleaners with custom Wi-Fi module. The final part of the thesis summarizes the achieved results.

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