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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.
31

A study proposing a data model for a dementia care mapping (DCM) data warehouse for potential secondary uses of dementia care data

Khalid, Shehla, Small, Neil A., Neagu, Daniel, Surr, C. 28 November 2020 (has links)
No / Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. There is growing emphasis on sharing and reusing dementia care-related datasets to improve the quality of dementia care. Consequently, there is a need to develop data management solutions for collecting, integrating and storing these data in formats that enhance opportunities for reuse. Dementia Care Mapping (DCM) is an observational tool that is in widespread use internationally. It produces rich, evidence-based data on dementia care quality. Currently, that data is primarily used locally, within dementia care services, to assess and improve quality of care. Information-rich DCM data provides opportunities for secondary use including research into improving the quality of dementia care. But an effective data management solution is required to facilitate this. A rationale for the warehousing of DCM data as a technical data management solution is suggested. The authors also propose a data model for a DCM data warehouse and present user-identified challenges for reusing DCM data within a warehouse.
32

Psychosocial Concerns of Patients with Dilated Cardiomyopathy

McFaddin, Andrew S. 12 September 2016 (has links)
No description available.
33

Energy Harvesting Circuit for Indoor Light based on the FOCV Method with an Adaptive Fraction Approach

Wang, Junjie 01 October 2019 (has links)
The proposed energy harvesting circuit system is designed for indoor solar environment especially for factories where the light energy is abundant and stable. The designed circuits are intended to power wireless sensor nodes (WSNs) or other computing unit such as microcontrollers or DSPs to provide a power solution for Internet of Things (IoTs). The proposed circuit can extract maximum power from the PV panel by utilizing the maximum power point tracking (MPPT) technique. The power stage is a synchronous dual-input dual-output non-inverting buck-boost converter operating in discontinuous conduction mode (DCM) and constant on-time pulse skipping modulation (COT-PSM) to achieve voltage regulation and maximum power delivery to the load. Battery is used as secondary input also as secondary output to achieve a longer lifecycle, a fast load response time and support higher load conditions. The proposed MPPT technique doesn't require any current sensor or computing units. Fully digitalized simple circuits are used to achieve sampling, store, and comparing tasks to save power. The whole circuits including power stage and control circuits are designed and will fabricate in TSMC BCDMOS 180 nm process. The circuits are verified through schematic level simulations and post-layout simulations. The results are validated to prove the proposed circuit and control scheme work in a manner. / Master of Science / With the growing energy demands, the efficient energy conversion systems caught great attentions. Especially, in the era of Internet of Things, powering those wireless devices can be extremely difficult. Nowadays, lots of devices such as consumer electronics, wireless sensor nodes, computing and mission system etc. are still powered by the batteries. Regular changing the batteries of those devices can be inconvenient or expensive. Energy harvesting provides a good solution to this issue because there are lots of ambient energy source is available. To design an energy efficient energy harvesting circuit system can help extend the device lifecycle per charging cycle. Even with some specific energy source which power scale is high enough, meanwhile the load doesn’t require too much power, the devices can be power-independent or standalone. In this work, the proposed circuit targets for indoor solar energy harvesting via solar panel. The target powering devices are wireless sensor nodes (WSNs). Meanwhile, WSNs can monitor the temperature, humidity, pressure, noise level etc. The proposed circuit design combines the power stage and control circuit on an integrated chip (IC), only few components are off-chip. It provides a very compact, endurable, and economical solution to the current IoT powering issue.
34

Μελέτη και κατασκευή διάταξης διασύνδεσης φωτοβολταϊκής γεννήτριας με το ηλεκτρικό δίκτυο χαμηλής τάσης

Αραβανής, Θεοφάνης 31 May 2012 (has links)
Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη, την ανάλυση καθώς και την κατασκευή μιας νέας τοπολογίας για τη διασύνδεση φωτοβολταϊκών (Φ/Β) γεννητριών, μικρής ισχύος, με το ηλεκτρικό δίκτυο των αστικών περιοχών. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Στόχος της διπλωματικής εργασίας είναι η συμβολή της στον τομέα των Φ/Β μονάδων διεσπαρμένης παραγωγής, με την κατασκευή μιας ηλεκτρονικής διάταξης, η οποία θα χρησιμοποιηθεί για τη διασύνδεση φωτοβολταϊκών (Φ/B) γεννητριών μικρής ισχύος, στο ηλεκτρικό δίκτυο χαμηλής τάσης. Συγκεκριμένα, διερευνάται και κατασκευάζεται ένας υψίσυχνος αντιστροφέας ρεύματος τοπολογίας Flyback, ο οποίος θα είναι κατάλληλος για εφαρμογές «Φωτοβολταϊκών Πλαισίων Εναλλασσόμενου Ρεύματος» (AC-PV Modules), δηλαδή Φ/Β διατάξεων, ηλεκτρικής ισχύος έως 300W, στις οποίες ενσωματώνεται ένας ηλεκτρονικός μετατροπέας συνεχούς τάσης σε μονοφασική εναλλασσόμενη (Micro-inverter). Ιδιαίτερα χαρακτηριστικά του αντιστροφέα που κατασκευάστηκε είναι ο μικρός βαθμός πολυπλοκότητας του κυκλώματος ισχύος με άμεση συνέπεια την υψηλή αξιοπιστία του, η γαλβανική απομόνωση που παρέχει ανάμεσα στη Φ/Β γεννήτρια και το ηλεκτρικό δίκτυο εναλλασσόμενου ρεύματος (Ε.Ρ.), η ικανότητα σημαντικής ανύψωσης της τάσης εισόδου του, ο υψηλός συντελεστής ισχύος, καθώς και ο υψηλός βαθμός απόδοσης (ο οποίος αγγίζει το 94,25%) για ένα ευρύ φάσμα λειτουργίας του. Ο μικρός όγκος και το μικρό βάρος (σε περίπτωση βιομηχανοποίησης), είναι επιπρόσθετα χαρακτηριστικά της συγκεκριμένης τοπολογίας. Αρχικά, αναλύεται διεξοδικά η λειτουργία του αντιστροφέα ρεύματος τοπολογίας Flyback, η οποία έχει αναπτυχθεί στη Διδακτορική Διατριβή του Αναστάσιου Χ. Κυρίτση, «Βέλτιστος Σχεδιασμός Υψίσυχνου Μονοφασικού Αντιστροφέα για τη Διασύνδεση Φωτοβολταϊκών Συστημάτων Μικρής Ισχύος με το Δίκτυο Χαμηλής Τάσης». Ταυτόχρονα, διερευνώνται δύο διαφορετικές τεχνικές ελέγχου, οι οποίες οδηγούν σε διαφορετικές καταστάσεις λειτουργίας (λειτουργία σε ασυνεχή αγωγή, DCM - λειτουργία στο όριο μεταξύ συνεχούς και ασυνεχούς αγωγής, BCM) και εξασφαλίζουν τη δημιουργία εναλλασσόμενου ημιτονοειδούς ρεύματος συμφασικού με την τάση του ηλεκτρικού δικτύου. Αναπτύσσονται τα κυκλώματα ελέγχου του αντιστροφέα, ενώ παρουσιάζεται ένας αποτελεσματικός τρόπος μέτρησης του υψίσυχνου διακοπτικού ρεύματος που διαρρέει τα τυλίγματα του μετασχηματιστή του αντιστροφέα. Τέλος, πραγματοποιείται η κατασκευή της διάταξης στο εργαστήριο, με σκοπό τη διεξαγωγή πειραματικών μετρήσεων για την επιβεβαίωση και αξιολόγηση της θεωρητικής ανάλυσης. / This degree thesis deals with the study, the analysis and the manufacture of a new topology that will be used for the interconnection of small photovoltaic (PV) generators with the electric network of urban regions. This work was conducted in the Laboratory of Electromechanical Energy Conversion, Department of Electrical and Computer Engineering, School of Engineering, University of Patras. The goal of the present thesis is to contribute in the sector of Dispersed Power Generation PV systems, with the development of an electronic device that will be used for the interconnection of small photovoltaic (PV) generators with the low voltage electric network. Specifically, a high frequency current source Flyback inverter is investigated and manufactured, that will be suitable for “Alternative Current Photovoltaic Modules” (AC-PV Modules) applications. An AC-PV Module is the combination of a single PV module (whose power production varies under 300W) and a single-phase power electronic micro-inverter in a single electrical device. Special characteristics of the inverter are the simple power electronic circuit structure, having high reliability as an immediate consequence, the electrical isolation provided between the PV generator and the electric network, the high power factor and the high efficiency (reaching 94.25%) for a wide range of its power. Moreover, small volume and weight are particular characteristics, attributes very important considering its applications (incorporation in PV generators that will be placed in aspects or roofs of buildings). For this topology - whose theory is in the Ph.D. thesis of A. Ch. Kyritsis “Optimum Design of a High Frequency Singe - Phase Inverter for the Interconnection of Small Power PV Systems with the Low Voltage Network” developed - two different control techniques were investigated, leading to different operation modes (Discontinuous Conduction Mode - DCM, Boundary between Continuous and Discontinuous Mode - BCM) and ensuring alternative sinusoidal current, in phase with the electric network voltage. Simultaneously, their suitability is studied for different power levels. Moreover, the control circuits of the inverter were developed and an effective way of measuring the high - frequency switching currents of the inverter’s transformer is presented. Last but not least, the design of the whole system is completed in the laboratory, in order to carry out the experimental measurements required, to confirm and evaluate the studied theory.
35

Analysis of splice-defect associated cardiac diseases using a patient-specific iPSC-cardiomyocyte system

Rebs, Sabine 28 September 2021 (has links)
No description available.
36

Vliv výběru souřadnic regionů na výsledky dynamického kauzálního modelování / Influence of region coordinates selection on dynamic causal modelling results

Klímová, Jana January 2013 (has links)
This thesis deals with functional magnetic resonance imaging (fMRI), in particular with dynamic causal modelling (DCM) as one of the methods for effective brain connectivity analysis. It has been studied the effect of signal coordinates selection, which was used as an input of DCM analysis, on its results based on simulated data testing. For this purpose, a data simulator has been created and described in this thesis. Furthermore, the methodology of testing the influence of the coordinates selection on DCM results has been reported. The coordinates shift rate has been simulated by adding appropriate levels of various types of noise signals to the BOLD signal. Consequently, the data has been analyzed by DCM. The program has been supplemented by a graphical user interface. To determine behaviour of the model, Monte Carlo simulations have been applied. Results in the form of dependence of incorrectly estimated connections between brain areas on the level of the noise signals have been processed and discussed.
37

Electrical investigations of hybrid OLED microcavity structures with novel encapsulation methods

Meister, Stefan, Brückner, Robert, Fröb, Hartmut, Leo, Karl 30 August 2019 (has links)
An electrical driven organic solid state laser is a very challenging goal which is so far well beyond reach. As a step towards realization, we monolithically implemented an Organic Light Emitting Diode (OLED) into a dielectric, high quality microcavity (MC) consisting of two Distributed Bragg Reflectors (DBR). In order to account for an optimal optical operation, the OLED structure has to be adapted. Furthermore, we aim to excite the device not only electrically but optically as well. Different OLED structures with an emission layer consisting of Alq3:DCM (2 wt%) were investigated. The External Quantum Efficiencies (EQE) of this hybrid structures are in the range of 1-2 %, as expected for this material combination. Including metal layers into a MC is complicated and has a huge impact on the device performance. Using Transfer-Matrix-Algorithm (TMA) simulations, the best positions for the metal electrodes are determined. First, the electroluminescence (EL) of the adjusted OLED structure on top of a DBR is measured under nitrogen atmosphere. The modes showed quality factors of Q = 60. After the deposition of the top DBR, the EL is measured again and the quality factors increased up to Q = 600. Considering the two 25-nm-thick-silver contacts a Q-factor of 600 is very high. The realization of a suitable encapsulation method is important. Two approaches were successfully tested. The first method is based on the substitution of a DBR layer with a layer produced via Atomic Layer Deposition (ALD). The second method uses a 0.15-mm-thick cover glass glued on top of the DBR with a 0.23-µm-thick single-component glue layer. Due to the working encapsulation, it is possible to investigate the sample under ambient conditions.
38

Numerisk beräkning av krypsättningar i pelarförstärkt lera / Numerical calculation of creep settlements in deep cement mixing

Johansson, Emil, Granlund Hedén, Victor January 2021 (has links)
I detta examensarbete har en utredning gjorts med syftet att undersöka lämpligheten att genomföra en djupstabilisering med multicementpelare (MC-pelare) i ett område med högt ställda sättningskrav. Detta genom att numeriskt simulera hur djupstabiliserad lera kan bete sig vid belastning med avseende på långtidsdeformationer. Vidare utvärderas hur väl olika materialmodeller kan simulera sättningar med hänsyn till kryp samt huruvida krypsättningar bör beaktas vid denna typ av dimensionering. Simuleringarna är genomförda enligt de geotekniska förutsättningarna och den planerade byggnationen på Galoppfältet i Täby Park. Som en grund för beräkningarna genomfördes en litteraturstudie där bland annat valet att simulera pelarna med Mohr-Coulomb (MoC), Soft Soil Creep (SSC) och Concrete Model (CM) i Plaxis 2D motiveras. Pelarna simulerades med en axissymmetrisk 2D-modell och i samtliga beräkningar simulerades leran med kryp medan pelarna simulerades både med och utan krypsättningar. En kalibrering mot tidigare forskning på området samt sättningsberäkningar av lera på Galoppfältet genomfördes för att säkerställa den valda modellens lämplighet. Därefter simulerades pelare med olika geometriska förutsättningar och varierande uppfyllnadshöjd. En sensitivitetsanalys gjordes även för att åskådliggöra vilka av de osäkra parametrarna som ger stor påverkan på resultatet. Simuleringarna visade att det antagligen är lämpligt att djupförstärka leran med multicementpelare för att uppnå låga sättningar över tid. För en pelardiameter på 800 mm och ett centrumavstånd på 1200 mm uppnåddes följande sättningar med de olika uppfyllnadshöjderna samt de olikamaterial modellerna. Av de testade pelarna ansågs denna geometri mest lämplig för de givna förutsättningarna på Galoppfältet. Detta baseras på den totala sättningen och att vissa pelare gick till brott i simuleringarna för övriga geometrier med större centrumavstånd och mindre pelardiameter. Beräkningarna där pelarna simulerades med SSC- och CM med kryp visade på stor variation sinsemellan. Resultaten med SSC anses felaktigt låga på grund av bristfälliga materialdata och visas därför inte i sammanfattningen. Resultaten med CM utan kryp och MoC utan kryp anses mest trovärdiga om än dock potentiellt för låga eftersom krypsättningar i pelarna inte är inkluderade. Vidare anses CM överlag vara en lämplig modell för att simulera sättningar med kryp i djupförstärkt lera förutsatt att ett tillräckligt underlag för val av materialparametrar finns att tillgå. SSC kan potentiellt vara lämplig enligt resultat från sensitivitetsanalysen förutsatt att materialparametrar kan undersökas för de lokala förutsättningarna. Dock förordas CM för fortsatta studier med krypsättningar i djupförstärkt lera. MoC anses som en god modell om kryp försummas. Med hänsyn till detta anser författarna att kryptester på multicementpelare bör övervägas för att skapa bättre förutsättningar för dimensionering av djupförstärkt lera med krypsättningar. Något som kan ge underlag för dimensionering med högre precision och potentiellt ekonomisk vinning. / This master thesis investigates the suitability of using multicement, a mixture of cement and cement kiln dust (CKD), for deep cement mixing (DCM) as soil improvement in an area with high requirements regarding the maximum allowed settlements. This was done by numerical modelling of long-term settlement behaviour for a DCM improved soil. Furthermore, the usability of different material models when considering creep behaviour are studied. The report also investigates whether creep behaviour should be considered or not in this type of simulation. The simulations are done according to the geotechnical conditions and the planned design for an old gallop track in Täby Park, Sweden. A literature review is done as a basis for the simulations performed in Plaxis 2D with an axis symmetric 2D-model. The use of Mohr-Coulomb (MoC), Soft SoilCreep (SSC) and Concrete Model (CM) for the columns are motivated. Creep settlements are included in the clay for all simulations while the columns are simulated both with and without creep settlements. To ensure the suitability of the model, a calibration is done by replication of a research study as well as replication of settlement calculations of the unimproved clay on Galoppfältet. Thereafter different geometric options for the columns and varying fill depths are simulated. Lastly a sensitivity analysis is conducted to display how much the uncertain material properties affect the result. Using multicement columns (MC columns) for DCM seems to be a good method for stabilizing the soil in Galoppfältet to achieve small settlements over time. For columns with a diameter of 800 mm and a center distance of 1200 mm the following settlements were calculated with the different material models for different fill heights. This geometry was considered most suitable for the conditions at Galoppfältet.  The two material models which account for creep in the columns show significantly different levels of total settlement. Due to lack of material data the results from simulations with SSC is deemed incorrect and thus not shown in the abstract. Thereby the results from MoC and CM without creep are deemed most credible even though they may be slightly low since they do not consider creep settlements in the columns. Furthermore, the Concrete Model is considered a good model to simulate settlements including creep in improved clay given that the material properties are carefully selected based on testing of the material. Soft Soil Creep may potentially be suitable for columns according to the calibration given that the different material parameters are investigated for the local conditions. However, CMare favoured. Mohr-Coulomb is deemed as a good model if creep settlements are neglected. With regards to this, the authors believe that creep tests of multicement columns should be considered to create improved preconditions for dimensioning of DCM columns with creep. This to improve the accuracy of design and potentially create cost reductions.
39

Demand-Supply Chain Management

Hilletofth, Per January 2010 (has links)
Purpose: This research aims to enhance the current understanding and knowledge of the demand-supply chain management (DSCM) concept by determining its elements, benefits, and requirements, as well as by analyzing key elements of the concept. Methodology: This research has utilized the case study strategy and the survey strategy, however, the case study strategy dominates. The case study research has involved five companies originating from Sweden and the collection of empirical data mainly from in-depth interviews with key persons representing senior and middle management. The survey research targeted the largest firms in Sweden and Finland and empirical data was collected through an online questionnaire. Findings: This research has established that the main elements of DSCM include market orientation, coordination of the demand and supply processes, viewing the demand and supply processes as being equally important, as well as value creation, differentiation, innovativeness, responsiveness, and cost-efficiency in the demand and supply processes. It has also been revealed that the main benefits of DSCM include enhanced competiveness, enhanced demand chain performance, as well as enhanced supply chain performance, while the main requirements of DSCM include organizational competences, company established principles, demand-supply chain collaboration, and information technology support. A key element of DSCM further investigated is differentiation focused supply chain design. It has been shown that these efforts can be organized into a process of five stages. In addition, it is important that this process is addressed in parallel with the new product development (NPD) process, that information is exchanged between them, and that they are directed on the basis of the same segmentation model. Another key element of DSCM further investigated is coordination between NPD and SCM. This research has identified several significant linkages between these management directions, which motivate the use of an integrative NPD process where the NPD functions are aligned with the main supply functions in the company and other sales-related functions supporting the commercialization. A final key element of DSCM further investigated is the significance of regarding the demand processes and the supply processes as being equally important. This research has revealed that logistics outsourcing can be risky, if it results in the supply processes being considered less important. Nevertheless, if senior management regards the outsourced processes as equally important as the in-house processes, the effect of logistics outsourcing on company strategies and direction in SCM could be reduced and logistics outsourcing could instead provide an opportunity to improve the design and differentiation of the supply chain. Research limitations/implications: This research has proposed, described, and further analyzed a demand-supply oriented management approach. Such a management approach stresses that the demand processes and the supply processes have to be coordinated and directed at an overlying level, in order to gain and sustain a competitive advantage in competitive and fragmented markets. This research is mainly explorative in nature, and more empirical data, from similar and other research settings, is needed to further validate the findings. Another limitation of the research is that it is essentially limited to Swedish companies (even if some Finnish companies are involved in the survey), however, many of the case companies have a large international presence and are among the top three in their industries, facts which provide some grounds for generalization. Practical implications: This research provides researchers and practitioners with insights into how to develop a demand-supply oriented business. It shows that companies should organize themselves around understanding how customer value is created and delivered, as well as how these processes and management directions can be coordinated. In order for this to occur, the demand and supply processes must be considered as being equally important and the firm needs to be managed jointly and in a coordinated manner by the demand- and supply-side of the company. It is also important that value creation is considered in both the demand and supply processes. Originality/value: Despite strong arguments from both researchers and practitioners for a demand-supply oriented management approach only a minority of companies appear to have effectively coordinated the demand and supply processes. This might be influenced by the lack of research examining how the demand and supply processes can be coordinated, what benefits can be gained by coordinating them, and what requirements are necessary to succeed. This research contributes by investigating these types of aspects further.
40

Dominance of the Unaffected Hemisphere Motor Network and Its Role in the Behavior of Chronic Stroke Survivors

Bajaj, Sahil, Housley, Stephen N., Wu, David, Dhamala, Mukesh, James, G. A., Butler, Andrew J. 27 December 2016 (has links)
Balance of motor network activity between the two brain hemispheres after stroke is crucial for functional recovery. Several studies have extensively studied the role of the affected brain hemisphere to better understand changes in motor network activity following stroke. Very few studies have examined the role of the unaffected brain hemisphere and confirmed the testretest reliability of connectivity measures on unaffected hemisphere. We recorded blood oxygenation level dependent functional magnetic resonance imaging (fMRI) signals from nine stroke survivors with hemiparesis of the left or right hand. Participants performed a motor execution task with affected hand, unaffected hand, and both hands simultaneously. Participants returned for a repeat fMRI scan 1 week later. Using dynamic causal modeling (DCM), we evaluated effective connectivity among three motor areas: the primary motor area (M1), the premotor cortex (PMC) and the supplementary motor area for the affected and unaffected hemispheres separately. Five participants manual motor ability was assessed by Fugl-Meyer Motor Assessment scores and root-mean square error of participants tracking ability during a robot-assisted game. We found (i) that the task performance with the affected hand resulted in strengthening of the connectivity pattern for unaffected hemisphere, (ii) an identical network of the unaffected hemisphere when participants performed the task with their unaffected hand, and (iii) the pattern of directional connectivity observed in the affected hemisphere was identical for tasks using the affected hand only or both hands. Furthermore, paired t-test comparison found no significant differences in connectivity strength for any path when compared with one-week follow-up. Brain-behavior linear correlation analysis showed that the connectivity patterns in the unaffected hemisphere more accurately reflected the behavioral conditions than the connectivity patterns in the affected hemisphere. Above findings enrich our knowledge of unaffected brain hemisphere following stroke, which further strengthens our neurobiological understanding of stroke-affected brain and can help to effectively identify and apply stroke-treatments.

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