• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 134
  • 93
  • 43
  • 30
  • 21
  • 10
  • 7
  • 6
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 392
  • 82
  • 51
  • 47
  • 33
  • 29
  • 28
  • 28
  • 26
  • 26
  • 26
  • 25
  • 23
  • 23
  • 22
  • 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.
241

Improved handling of a sample holder goniometer at Uppsala University’s Tandem Laboratory

WU-VIGNOLO, Alexander January 2020 (has links)
Rutherford backscattering spectrometry are performed at the Tandem Laboratory of Uppsala Univer-sity, providing information on thickness and composition of materials. To avoid the channelling effect,a wiggling routine has been created to randomly move the sample holding goniometer during the spec-trum acquisition. The aim of this project is to incorporate this routine into the batch measurement infrastructure.
242

Development of Reliability Test Rigs for Total Artificial Heart Pumps / Utveckling av reliabilitets-testanordningar för totalt artificiella hjärtpumpar

Besic, Alisa, Ogeborg, Martin January 2022 (has links)
The long-term performance of TAH pumps needs to be demonstrated. Reliability tests are performed to measure its ability to operate for months, or years, without failure. Real Heart is currently constructing test rigs for this purpose. Software for documenting test rig conditions is also required. Thus, the objective of this study is to assist in developing reliability test rig software.  The software is written in LabVIEW and is hosted on a CompactRIO controller. Requirements include sampling of sensor data, logging, and alarms. Additionally, a PC dashboard is constructed for monitoring real-time data, reviewing logs, as well as controls for acquisition. Results of this study present a foundation for the test rig software. It features a modular architecture which allows for future scalability. The process of development involves research of hardware/software, establishing a reference design and to build and validate each module through test simulations. Data acquisition is set up with the NI-DAQmx API. It features automatic configuration for thermocouple, as well as custom signal scaling of the pressure and flow transducers. However, grouping of data and synchronization for logging and alarms was a challenge. The producer/consumer design pattern is implemented for grouping data as well as synchronization for logging and alarms. / Det artificiella hjärtats långsiktiga prestanda måste demonstreras. Tillförlitlighetstester utförs för att mäta pumparnas förmåga att fungera i månader eller år utan att gå sönder. Real Heart bygger för närvarande testriggar för detta ändamål. Programvara för att dokumentera testriggens förhållanden behövs också. Därför är syftet med denna studie att hjälpa företaget med att utveckla programvara för tillförlitlighetstestriggar.  Programvaran är skriven i LabVIEW och används på en CompactRIO-kontroller. Den kommer inkludera provtagning av sensordata, loggning och alarm. Dessutom är en PC-instrumentpanel konstruerad för övervakning av realtidsdata, granskning av loggar samt kontroll av datainsamling. Resultaten av denna studie utgör en grund för testriggens programvara. Den har en modulär arkitektur som möjliggör framtida uppskalning. Utvecklingsprocessen involverar studier av hårdvara/programvara, upprättande av en referensdesign, samt att bygga och validera varje modul genom testsimuleringar. Datainsamling genomförs med NI-DAQmx API. Den har automatisk konfiguration för temperatur, samt anpassad signalskalning av tryck- och flödesgivare. Designmönstret producent/konsument implementerades för gruppering av data, samt synkronisering för loggning och alarm.
243

Theoretical and Experimental Study of Active Magnetic Bearing Control Integrated on Bently's Rotor Kit

Flores, Arturo Mario 01 August 2023 (has links) (PDF)
This thesis focuses on the comprehensive study of controlling a customized Active Magnetic Bearing (AMB) installed on Bently Nevada’s RK4 rotor kit in Cal Poly’s Vibrations and Rotordynamics Lab. The AMB was uniquely designed and manufactured by a Cal Poly senior project team to fit Bently’s rotor kit and the results of this research are distinctive to the custom system. To achieve practical functionality of the AMB system, we designed a controller a Virtual Instrument (VI) using the National Instrument software, LabVIEW. From the experimental study, we calibrated the programming to find unknown parameters of the AMB system and validated the design using a well-established industrial rotordyanmics software, Bentley Nevada System 1. The development of the control programming consists of theoretical analysis (MATLAB/ Simulink) and simulation validation (MSC ADAMS View). Both linear and non-linear models were implemented in MATLAB and Simulink to effectively tune a Proportional-Integral-Derivative (PID) control developed for various AMB models. To validate the theoretical results, we compared them to results from a co-simulation using MSC Adams VIEW, a multi-body dynamics simulation, and Simulink. From experimental trial and error at a shaft rotational speed of 2800 rpm, a 16% decrease in shaft orbit was achieved. These results demonstrate the practicality of the control program and custom AMB rotor kit that can be used for further research.
244

An integrated real-time system for multimodal monitoring of Traumatic Brain Injury (TBI)

Ramaswamy, Bharat Ram 11 October 2012 (has links)
No description available.
245

Enabling the use of Heterogeneous Computing for Bioinformatics

Bijanapalli Chakri, Ramakrishna 02 October 2013 (has links)
The huge amount of information in the encoded sequence of DNA and increasing interest in uncovering new discoveries has spurred interest in accelerating the DNA sequencing and alignment processes. The use of heterogeneous systems, that use different types of computational units, has seen a new light in high performance computing in recent years; However expertise in multiple domains and skills required to program these systems is causing an hindrance to bioinformaticians in rapidly deploying their applications into these heterogeneous systems. This work attempts to make an heterogeneous system, Convey HC-1, with an x86-based host processor and FPGA-based co-processor, accessible to bioinformaticians. First, a highly efficient dynamic programming based Smith-Waterman kernel is implemented in hardware, which is able to achieve a peak throughput of 307.2 Giga Cell Updates per Second (GCUPS) on Convey HC-1. A dynamic programming accelerator interface is provided to any application that uses Smith-Waterman. This implementation is also extended to General Purpose Graphics Processing Units (GP-GPUs), which achieved a peak throughput of 9.89 GCUPS on NVIDIA GTX580 GPU. Second, a well known graphical programming tool, LabVIEW is enabled as a programming tool for the Convey HC-1. A connection is established between the graphical interface and the Convey HC-1 to control and monitor the application running on the FPGA-based co-processor. / Master of Science
246

Digital Twin Sterilizer

Jacobsson, Sebastian, Johnsson, Marcus January 2024 (has links)
An autoclave is an advanced machine that sterilizes objects using high-pressure and high heat, with water steam as the medium. Autoclaves are frequently found in hospitals and other places where sterility is required. This project aims to meet the company's need to create a digital twin (DT) of an autoclave. The purpose is to test the control unit that controls the physical autoclave by exposing the DT to the same program as a real autoclave. A DT is a virtual model of a physical system, and in this project, it represented the autoclave and its sensors. The model was programmed in a graphical programming language NI LabView, with the same input and output signals as a real autoclave. The model was based on data-driven logic rather than physical based logic. From a real autoclave run where signals were recorded every second, conclusions could be drawn about how much each unique analog signal changed in combination with other signals through interpolation. The interpolation of the analog signals was used to capture the characteristics of these signals.  For validation, the DT was loaded into a Hardware In the Loop (HIL) system that simulates the autoclave with the DT but retains the control unit from the autoclave, which is the unit the company wants to test. The developed DT was tested against three goals describing how closely the values should align over an accumulated time. The results were compared each second between the real run and the DT run. The data-driven DT model met one of the three goals set, however, the DT model's characteristics resembled those of the real run, making the model useful as the control system does not interrupt the simulation for disallowed or deviant values. / En autoklav är en avancerad maskin som rengör objekt till en steril nivå med ett högt tryck och hög temperatur, där vattenånga används som medium. Autoklaven har ett vanligt förekommande på sjukhus och andra platser där sterilitet är ett krav. Det här projektet går ut på att möta företagets behov av att skapa en digital tvilling (DT) av en autoklav. Syftet är att testa kontrollenheten som styr den fysiska autoklaven genom att en DT ska utsättas för samma programkörning som en verklig autoklav. En DT är en virtuell modell av ett fysiskt system och i detta projekt var autoklaven och sensorerna i maskinen en DT. Modellen programmerades i ett grafiskt programmeringsspråk, NI LabVIEW med samma in- och utsignaler som en verklig autoklav. Modellen utgår ifrån en datadriven metod och inte en fysikalisk formulerad logik. Datan samlades in från en körning av en verklig autoklav, där signalerna sparades varje sekund. Slutsatser för hur mycket varje unik analog signal förändrades i kombination med övriga signaler kunde dras med hjälp av interpolering. Interpoleringen av de analoga signalera kunde användas för att fånga deras karakteristik.  För validering integrerades DT i ett Hardware In the Loop (HIL) system som hjälper till att simulera autoklaven. HIL-systemet har kontrollenheten kvar från autoklaven som är den enhet företaget vill utföra tester på. Den framtagna DT testades mot tre mål som beskriver hur nära värdena skall ligga under en ackumulerad tid. Resultatet jämfördes för varje sekund mellan den verkliga och DT körningen. Den datadrivna DT modellen uppfyllde 1 av 3 mål som ställdes, men DT modellens karakteristik efterliknade den från verkliga körningen vilket gör modellen användbar då kontrollsystemet inte avbryter simuleringen för ej tillåtna eller avvikande värden.
247

LabVIEW implementation of a neural network based solution to the angle of arrival estimation problem

Haralambous, Shinling S. 01 January 1999 (has links)
No description available.
248

Ανάπτυξη ενός "συστήματος τεχνητής νοημοσύνης" ενεργού ελέγχου δονήσεων και θορύβου με τη χρήση ενός τεχνητού νευρωνικού δικτύου και ενός γενετικού αλγορίθμου / Development of an "expert system" for active vibration and noise control by means of an artificial neural network and a genetic algorithm

Ευθήμερος, Γεώργιος 11 August 2011 (has links)
Είναι ευρύτατα γνωστό ότι ο θόρυβος δημιουργείται από δονούμενες επιφάνειες. Για την αντιμετώπιση του θορύβου στην πηγή του, δηλαδή τη δονούμενη επιφάνεια, δύο κυρίως τρόποι έχουν αναπτυχθεί. Ο πρώτος τρόπος αφορά τη χρησιμοποίηση παθητικών μέσων, δηλαδή ηχομονωτικών υλικών που αποσβένουν συγκεκριμένες συχνότητες. Ο δεύτερος τρόπος αφορά τη χρήση ενεργητικών μέσων. Τα ενεργητικά μέσα είναι διατάξεις που αποτελούνται από ένα σύστημα ελέγχου και ένα σύνολο αισθητήρων και ενεργοποιητών. Η λειτουργία ενός τέτοιου Συστήματος Ενεργού Ελέγχου Δονήσεων (ΣΕΕΔ) βασίζεται στην καταγραφή μέσω των αισθητήρων του τρόπου δόνησης της επιφάνειας (πρωτεύον πεδίο δόνησης), την δημιουργία σημάτων ελέγχου από τον ελεγκτή (ίδιου πλάτους αλλά με διαφορά φάσης 180o) και την αποστολή τους στους ενεργοποιητές που θα δημιουργήσουν ένα δευτερεύον πεδίο δόνησης. Η υπέρθεση των δύο πεδίων έχει σαν αποτέλεσμα την δημιουργία ενός εναπομείναντος πεδίου με πλάτη δόνησης αισθητά χαμηλότερα από αυτά του πρωτεύοντος. Το αντικείμενο της παρούσας διατριβής είναι η ανάπτυξη ενός γενικευμένου ΣΕΕΔ, ο έλεγχος του οποίου βασίζεται σε εργαλεία Τεχνητής Νοημοσύνης όπως τα Τεχνητά Νευρωνικά Δίκτυα και οι Γενετικοί Αλγόριθμοι για την αναγνώριση του τρόπου δόνησης οποιασδήποτε επιφάνειας και το βέλτιστο έλεγχο της δόνησής της, χωρίς να απαιτείται καμία πρότερη γνώση της δυναμικής συμπεριφοράς της επιφάνειας. Επιπλέον, το υπό μελέτη ΣΕΕΔ είναι ικανό να ελέγχει τέσσερις συχνότητες αντί μιας που απαντάται συνήθως στην πλειονότητα των εφαρμογών. Ο σκοπός της διατριβής αυτής είναι η απόδειξη της αρχής λειτουργίας ενός τέτοιου συστήματος. Η προσέγγιση για την επίτευξη αυτού του στόχου περιλαμβάνει πειραματικές μετρήσεις ενός πρωτότυπου ΣΕΕΔ σε μία απλοποιημένη πειραματική διάταξη. Τα αποτελέσματα από την εφαρμογή του εν λόγω ΣΕΕΔ δείχνουν ότι παρά τους περιορισμούς που υπεισέρχονται λόγω των δυνατοτήτων του υλικού (hardware) του χρησιμοποιούμενου εξοπλισμού, το υπό μελέτη ΣΕΕΔ λειτουργεί επιτυχώς στη βασική αρχή του, ενώ έχει τις προϋποθέσεις και τη δυναμική για περαιτέρω βελτιστοποίηση και εξέλιξη σε ένα ευρύ φάσμα εφαρμογών. / It is generally approved that noise is created by vibrating surfaces. In order to tackle this phenomenon at its source, mainly two approaches have been followed. The first approach involves passive means, that is sound insulation materials that dampen certain frequencies. The second approach involves the use of active means. The active means are arrangements that consist of a control system and a set of sensors and actuators. The application of such an arrangement for vibration control is called Active Vibration Control (AVC) and is based on the sampling (by means of sensors) of the primary field of vibration of the surface, the creation of control signals by the controller (secondary field - of the same amplitude but with phase difference of 180o) and finally applying these control signals on the vibrating surface, by means of the actuators. The superimposing of the two vibration signals (primary and secondary) results to a residual field where the amplitudes of vibration are significantly lower than in the primary. The objective of the thesis at hand is to develop a Generic AVC with the controller developed using Artificial Intelligence tools such as the Artificial Neural Networks (ANNs) and Genetic Algorithms (GAs), in order to identify the vibration patterns of any surface and the optimal control of its vibration, without any prior knowledge of the dynamic behavior of the surface. Moreover, the developed AVC system will be able to identify and control four dominating frequencies instead of one that is usually the choice in the majority of similar applications. The scope of this work is the ‘Proof of Concept’ of the successful operation of such a generic AVC system. The approach to this end includes experimental testing of a prototype AVC system on a simplified experimental set-up. The results of the application of the developed AVC system, performed also by independent parties in the framework of a EC-funded Basic Research project, prove the successful operation of the developed AVCS, even within the limitation of the contemporary data acquisition platform (hardware and software) used, imposes limitations in the efficiency of the AVCS, and provide the basis for its further development and application in a multitude of problems.
249

Automatizace trati pro měření vodních ventilů / Automation of track for measurement of water valves characteristics

Lekeš, Pavel January 2014 (has links)
My diploma thesis describes upgrade of flowbench serving as test rig for regulation valves characteristic measurement. At the beggining, there is an introduction to the water regulation valves theory followed by current machine condition description. Next chapter defines needed improvements and at the end follows proposition of improvements and necessary component definition and final realization. Final chapter summarizes complete project.
250

Automatizace trati pro měření vodních ventilů / Automation of track for measurement of water valves characteristics

Lekeš, Pavel January 2014 (has links)
My diploma thesis describes upgrade of flowbench serving as test rig for regulation valves characteristic measurement. At the beggining, there is an introduction to the water regulation valves theory followed by current machine condition description. Next chapter defines needed improvements and at the end follows proposition of improvements and necessary component definition and final realization. Final chapter summarizes complete project.

Page generated in 0.0171 seconds