• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 61
  • 25
  • 11
  • 10
  • 7
  • 7
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 142
  • 21
  • 18
  • 16
  • 15
  • 14
  • 14
  • 13
  • 13
  • 12
  • 12
  • 10
  • 10
  • 10
  • 10
  • 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

The Detection of Ischemic Stroke on the PSD Manifold of EEG Signals

Zhang, Canxiu January 2018 (has links)
The study of ischemic brain stroke detection by Electroencephalography (EEG) signal is the area of binary signal classification. In general, this involves extracting features from EEG signal on which the classification is performed. In this thesis, we investi- gate the employment of Power Spectral Density (PSD) matrix, which contains not only power spectrum contents of each signal which complies with what clinical experts use in their visual judgement of EEG signals, but also cross-correlation between multi-channel (electrodes) signals to be studied, as a feature in signal classification. Since the PSD matrices are structurally constrained, they form a manifold in the signal space. Thus, the commonly used Euclidean distance to measure the similarity/dissimilarity between two PSD matrices are not informative or accurate. Riemannian Distance (RD), which measures distance along the surface of the manifold, should be employed to give more meaningful measurements. Furthermore, two classification methods, binary hypothesis testing and K-Nearest Neighbors (KNN), are applied. In order to enhance the detec- tion performance, algorithms to find optimum weighting matrix for each classifier are also applied. Experimental results show that the performance by the kNN method us- ing PSD matrix as features with RD as similarity/dissimilarity measurements are very encouraging. / Thesis / Master of Applied Science (MASc)
2

A Study on the Displacement Measurement of Meso-objects Using PSDs

Lin, Wei-Ran 27 August 2009 (has links)
Precision measurement technologies have been developed for a long time. Measuring the displacement of meso-scale objects became an important issue in the recent years. In this study, a displacement measurement system for meso-scale objects is developed by combining the measurement technique of using position sensing detectors (PSD) and the grinding skill of fabricating micro scale reflection surfaces on optical fiber tips. This measurement system can be used for detecting the postweld shift (PWS) of a laser-welded butterfly-type laser diode module package. The PWS affects the coupling efficiency of a laser-welded butterfly-type laser diode module package quite a lot. Although there are many papers studied the measurement of PWS, most of the measurements are less than 6 degrees of freedom (DOF). The system developed in this paper can measure the 6 DOF displacement of the PWS. An attachment for carrying 3 micro reflection probes is designed firstly which will be settled on the fiber ferrule of a laser diode module. After all the coordinate transformation matrices of the laser beam light source, micro reflection surfaces, and the position sensing detectors are derived as well as the PSD readings are taken, displacements of the ferrule of a laser diode module can be solved from the displacement equations by using numerical method. The system developed in this paper is implemented on a Newport butterfly-type laser diode module package station (Model LW4200) for demonstration. The testing results show that the resolution of this system is 1£gm and the accuracy is 2£gm. Beside the application of measuring the 6 degrees of freedom PWS of a laser diode module package, the system developed in this paper can also be applied for measurement the displacement of other meso-scale objects.
3

Automatizuotas grafinio internetinio interfeiso sudarymas / Automated graphic web interface creation

Barauskas, Tadas, Balčiūnas, Raimundas 26 August 2013 (has links)
Tiek tinklapio projektuotojui, tiek programuotojui apdoroti ir pritaikyti sukurtą grafinį dizainą internetiniams tinklapiams yra sudėtingas bei laiko sąnaudas suvartojantis procesas. Darbo tikslas palengvinti šį procesą sutaupant tiek darbo, tiek laiko kaštų vartotojams susijusiems su tiriama sritimi. Tikslui įgyvendinti sukurta internetinėje aplinkoje veikiančią programinę įrangą, kuri supaprastina ir palengvina internetinių grafinių šablonų kūrimą. Programinė įranga kurta pasitelkus PHP, CSS ir JAVA programavimo kalbas. Galutinis darbo produktas iš Photoshop įrankiu sukurto grafinio tinklapio eskizo generuoja tiek statinį tinklapio šabloną, tiek pritaiko šio šablono grafinius elementus turinio valdymo sistemos grafiniam atvaizdavimui. Nors jau egzistavo panašių įrankių (atliekančių panašias funkcijas), tokių kaip Adobe Fireworks ir Psd2CssOnline, tačiau šie įrankiai nusileido atpažįstamų elementų kiekiu ir kokybe. Tai patvirtino darbe atliktas tyrimas. / To process and adjust a graphical design for web pages is a difficult and time consuming task for both: designer and developer. The main goal of this work was to make this task less time and effort consuming. To achieve this goal a web accessible software tool was created in our work. This automated tool can analyze graphical project files (made with Adobe Photoshop) and output desired end result, thus preserving time and effort. The developed tool analyzes initial file layer by layer and automatically assigns appropriate parameters to CSS and html patterns. These patterns then can be extracted as static web pages or with a next step these patterns can be adjusted to fit a chosen content managing system. Although there already are some similar products with the same functionality (such as Adobe Fireworks or Psd2CssOnline), the developed tool was greater in quality and quantity of recognizable web elements. This was proven by the research provided in this work.
4

Biophysical analysis and NMR structural characterization of the binding between peptidomimetic drug CN2097 and scaffolding protein PSD-95

Hu, Tony Ken 12 June 2019 (has links)
BACKGROUND: At the postsynaptic membrane of neurons there is a dense network of proteins called the postsynaptic density (PSD). One such protein is the postsynaptic density protein 95 (PSD-95), which functions as a molecular scaffold for forming protein complexes at the PSD. PSD-95 is composed of three PDZ domains, which studies have shown to be sequentially and structurally similar. Studies have shown that PSD-95 plays a role in regulating signaling of glutamatergic neurons, as well as the induction of longterm potentiation through an association with TrkB receptors. PSD-95 may be a promising target for treatment of a number of neurological disorders such as depression, epilepsy, and cognitive dysfunction. The cyclic peptidomimetic drug CN2097 was designed based on the PDZ-binding motif of the CRIPT protein that binds to PDZ3. While CN2097 has been shown to affect the binding of PSD-95 to different synaptic proteins, no NMR studies have been performed to characterize the binding of CN2097 to PDZ3. Furthermore, few studies have characterized the inter-domain interactions between PDZ domains or whether the binding of calmodulin (CaM) to the N-terminal region of PSD-95 has any effect on the binding between the PDZ domains and CN2097. OBJECTIVE: To use isothermal titration calorimetry and nuclear magnetic resonance spectroscopy to analyze and characterize how CN2097 binds to PDZ domains and whether inter-domain interactions exist between PDZ domains. METHODS: The gene sequences for the PDZ domains were inserted into the pET28a(+) vector by subcloning. E. coli bacteria were then transformed with the different PDZ plasmids. The bacterial cells were grown and induced to express the proteins of interest, followed by lysis and purification using affinity chromatography and fast protein liquid chromatography (FPLC). Isothermal titration calorimetry (ITC) was used to measure the dissociation constant and thermodynamic binding parameters between the peptidomimetic drug CN2097 and each isolated PDZ domain. Nuclear magnetic resonance (NMR) spectroscopy was used to study how CN2097 binds to PDZ1 and PDZ3, and how the PDZ domains interact with each other. RESULTS: The ITC data showed the dissociation constant between CN2097 and PDZ3 to be 5.12 ± (1.65) μM, and that of PDZ2+3 to be 42.63 ± (6.11)μM. ITC data on other domains was inconclusive. The NMR data showed no interaction between N-terminal region and PDZ1, and between PDZ2 and PDZ3 but significant interaction was seen between PDZ1 and PDZ2, as well as between PDZ3 and the inter-domain linker connecting it to PDZ2. NMR data showed that CN2097 binding perturbs PDZ3 more strongly than PDZ1 and that CN2097 does not bind to PDZ1 in the presence of CaM. Significant NMR chemical shift perturbations are seen on the second α-helix, second β- sheet, and β2-β3 loop. CONCLUSIONS: There are no significant contacts between the N-terminal α-helix and PDZ1. There is inter-domain conformational exchange and interaction between PDZ1 and PDZ2. PDZ3 interacts with the second inter-domain linker. CN2097 binds tighter to PDZ3 than to PDZ1, and does not bind to PDZ1 in the presence of CaM. The β2-β3 loop is a prime target for future development of CN2097.
5

The nanostructural organisation of PSD-95 at the synapse

Broadhead, Matthew James January 2016 (has links)
Synapses are the communication junctions of the nervous system and contain protein machinery necessary for cognitive functions such as learning and memory. Postsynaptic density protein-95 (PSD-95) is a key scaffolding molecule at the PSD of synapses, yet its sub-synaptic organisation in the mammalian brain remains poorly understood. This thesis presents the use of genetically labelled PSD-95 with super-resolution imaging to resolve its nano-architecture in the mouse brain. To visualize PSD-95, two knock-in mouse lines were generated where the fluorescent proteins eGFP or mEos2 was fused to the carboxyl terminus of the endogenous PSD- 95 protein (PSD-95-eGFP or PSD-95-mEos2). Methods were developed by which fixed tissue sections of PSD-95-eGFP mice were examined using gated-stimulated emission depletion (g-STED) microscopy and PSD-95-mEos2 sections were examined with photoactivatable localisation microscopy (PALM) and quantitative image analysis was developed for both methods. From these platforms it was demonstrated that PSD-95 has a two tiered organisation: it is assembled into nanoclusters (NCs) approximately 140 nm diameter, which form part of the greater envelope of the PSD within synapses. Synapse subtypes were observed as characterised by the number of NCs per PSD. Using double colour g- STED microscopy. It was then asked whether PSD-95 nano-architecture remained the same across different sub-regions of the brain. A survey of PSD-95 was performed from seven different sub-regions of the hippocampus, quantifying ~110,000 NCs within ~70,000 PSDs from across the two super-resolution platforms. It was found that synapses displayed structural diversity both within and between different brain subregions as a function of the number of NCs per PSD. PSD-95 NCs were structurally conserved across the hippocampus, but showed molecular diversity in the abundance of PSD-95 molecules within. The findings of this thesis are: 1) genetic labelling of endogenous proteins combined with super-resolution microscopy is a powerful tool to study synaptic protein organisation in tissue. 2) Synaptic structural diversity in the brain is underlined by the number of PSD-95 NC units per synapse 3) PSD-95 NCs are structurally conserved but molecularly diverse synaptic units of synapses throughout the brain. These findings suggest that cognitive processing at the synapse is based upon a conserved, fundamental, molecular architecture.
6

Optimisation des procédures de tests pour simulation de transport des systèmes d'emballage, à partir de l'analyse statistique et fréquentielle du signal vibratoire excitateur / Development of specific procedures for testing dynamic packaging systems, from data acquisition and in-situ modeling of the dynamic behavior of these systems

Otari, Suzan 13 December 2011 (has links)
Parmi les tests utilisés dans un plan de qualification destiné à qualifier un emballage ou un système d’emballage pour résister pendant le transport, l’essai en vibrations aléatoires est un moyen efficace pour reproduire les effets mécaniques vibratoires dus au transport. La méthode habituelle s’intéresse uniquement à la répartition fréquentielle du signal en utilisant la densité spectrale de puissance (PSD) et la répartition statistique des niveaux du signal est complètement négligée.Dans ce travail nous avons proposé une loi de distribution de ces niveaux d’accélération qui identifie et caractérise statistiquement le signal vibratoire. L’enregistrement en continu du signal d’accélération tout au long d’un trajet a permis de montrer que cette distribution statistique n’est pas une gaussienne mais une gaussienne modifiée dont les paramètres sont estimés et discutés. Par suite, il est possible de caractériser la sévérité d’un trajet par une comparaison avec la distribution gaussienne qui a la même valeur efficace. Ce modèle retenu nous permet de le comparer aux autres signaux actuellement utilisés pour simuler de tels trajets. L’objectif étant à terme de proposer une méthode alternative de pilotage sur certains systèmes de vibrations (chapitre VI).En générale on utilise un enregistrement partiel du signal vibratoire afin de simuler ses effets mécanique en laboratoire de test sans connaître les conséquences d’un tel mode d’enregistrement sur les caractéristiques du signal étudié. Au cours de ce travail (chapitre 3 et 4) l’effet d’enregistrement partiel du signal est étudié sur les caractéristiques statistiques et fréquentielles de celui-ci. Nous avons montré que lors d’un trajet routier en France 10% du temps total du trajet est représentatif de sa totalité. Si l’enregistrement est effectué avec des taux inférieurs à 10%, nous somme capables d’estimer l’erreur introduite sur la distribution des valeurs du signal et aussi sur le niveau de le PSD. Ainsi cette erreur peut être corrigée au moment de la simulation en laboratoire.Enfin nous avons proposé une méthode alternative pour simuler le signal non-stationnaire et non-gaussien par un système de vibration habituellement utilisé pour cet effet qui consiste à une séquence des signaux gaussiens. Cette méthode a été proposée en vu des moyens et matériels que dispose la société Metropack et leur permet de simuler des effets vibratoires à la façon la plus proche de la réalité du transport. / Several tests are used to qualify a packaging or a packaging system aimed for transportation. This is called qualification plan. Random vibration tests are an efficient way to simulate the mechanical vibratory effects caused by transportation. The usual method is only concerned with the frequency distribution pattern of the signal using the average power spectral density (PSD) but statistical distribution of levels is totally ignored.In this work we have proposed a statistical model based on analyse of instantaneous acceleration levels of road transport, which identify and characterise the vibration signal. Continuous recording of acceleration signal all along the journey permits confirmation that this statistical distribution is not a Gaussian distribution but a modified Gaussian distribution, for which parameters are estimated and discussed. Therefore, it is possible to evaluate the transport severity by working out the appearance probability of acceleration levels greater than a fixed threshold and also the difference between the experimental distribution and the Gaussian distribution with the same rms value. This model is used to correcting the way of simulation in a test laboratory (chapter 5).Usually to recreate the mechanical effects of a vibration signal in the test laboratory, we use a partial recording of this signal without any adequate attention on effects of the recording parameters on characteristics of signal recorded in this way. In this work (chapter 3 and 4), the effects of partial recording is studied on statistical and frequency characteristics of acceleration signal. We have shown that for a road transport in France only 10% of the total duration of a journey must be taken to represent the whole journey. If the recording is performed with rates below 10%, we are able to estimate the error introduced on the distribution of signal and also on the level of the PSD. So this error can be corrected when the journey is simulated in laboratory.Finally we have proposed an alternative method for simulating the non-stationary and non-Gaussian signal with a typically used vibration system for this purpose which consists of a sequence of Gaussian signals. This method was proposed considering the means and materials available at company (Metropack) and enables them to simulate vibration effects in the most realistic way.
7

Estimation of fatigue life of welded joint using vibration-fatigue computational model

Subramanian, Eniyavan 12 April 2016 (has links)
Heavy vehicle structures are made from welded carbon steel frames. During operation these frames are subjected to random dynamic loads, which induce fatigue at the welded joints. A Finite Element based process for calculating fatigue life of welded joint under single excitation random loading is proposed in this study. The proposed method com-bines Equivalent Equilibrium Structural Stress (E2S2) method for weld fatigue and PSD based vibration fatigue technique for handling random loads. Fatigue life of a welded T-joint is analysed using the proposed method in frequency domain and validated against a transient dynamic analysis. The main advantage of the proposed method is the analysis run time is reduced almost 12 times compared to transient analysis. Effect of geometric changes on weld fatigue life is studied. It is found the tube thickness increase at lower thickness ranges significantly increases the fatigue life compared to higher thickness ranges. / May 2016
8

Marknadsstrategier för andningslarm, ett samarbete med F.O.V. Fabrics AB / Marketing strategies for breathing alarms, in cooperation with F.O.V. Fabrics AB

JING, HAST, ELISABETH, GRÖNBERG, JOSEFIN, CARLSSON January 2011 (has links)
Varken läkare eller forskare har kunnat lösa gåtan kring fenomenet plötslig spädbarnsdöd. Detta syndrom drabbar spädbarn, vanligtvis när de är 8-12 veckor gamla, utan att någon förklaring kan ges. Endast i Sverige dör cirka 13 spädbarn per år. Läkare har under åren kommit med förebyggande råd men någon säker metod som förhindrar syndromet existerar inte. Samtidigt finns det olika former av andningslarm som alternativ om föräldrarna vill övervaka spädbarnets andningsrörelser. F.O.V. Fabrics AB i Borås har en produktprototyp under utveckling och vi har på uppdrag av dem analyserat marknaden och dess möjligheter. Av de undersökningar som gjorts framgår det att kunskapen om plötslig spädbarnsdöd är relativt liten, främst hos män. Att det finns produkter på marknaden är inte heller allmänt känt. Målgruppen har i denna rapport definierats och en marknadsmix har sammanställts, dessutom redovisas förslag på olika distributionsmöjligheter. Produkten måste även stå för kvalitet så att konsumenterna känner sig trygga med den. Skulle barnet sluta andas kommer larmet, inom 20 sekunder, att ljuda och i det läget är det viktigt att kunden har fått rätt information om hur första hjälpen ska utföras för att kunna rädda barnet. Av den orsaken är det viktigt att inte bara information om produkten sprids, information om hur man ska använda den är minst lika viktigt. / Program: Textil produktutveckling med entreprenörs- och affärsinriktning
9

Defferential expression of isoforms of PSD-95 binding protein (GKAP/SAPAP1) during rat brain development / PSD-95結合蛋白質(GKAP/SAPAP1)のラット脳発育過程における発現の多様性

川嶋, 望 25 March 1998 (has links)
共著者あり。共著者名:Takamiya Kogo(高宮考悟), Sun Jie(孫傑), Kitabatake Akira(北畠顕), Sobue Kenji(祖父江憲治). / Hokkaido University (北海道大学) / 博士 / 医学
10

Termostat pro měření pasivních součástek řízený AVR / Thermostat for measuring passive component controlled of AVR

Demjanics, Ferenc January 2011 (has links)
The aim of this work is to familiarize with the design of the thermal test chamber to measuring passive components. Show features and involvement of selected circuits that ensure reliable operation of the device. For the realization of the role are the most important the Peltier cells and temperature sensors. But they can not work without the control unit. The control unit provides the necessary communication with each component and also with user. For this purpose we made a selection of suitable type of microcontroller and communication equipment (matrix keypad, LCD, buttons and LEDs). Subsequently was designed the algorithm to control the thermostat suitable for using in students training. The algorithm was written in the microcontroller in form of a program. There is also implemented a PSD controller in the program, which evaluates the data collected by a sensor. Then set the correct function of Peltier cells. After the thermostat was designed and realized, test measurements were performed and the results were documented and evaluated.

Page generated in 0.0631 seconds