Global ETD Search

91	Analýza registrů Microsoft Windows / Microsoft Windows Registry Analysis Hula, Miroslav January 2011 (has links) Understanding and working with Microsoft Windows registry is an important ability from the perspective of security. This ability is used by malicious software as well as by software, which repaires the damage caused by activity of malicious software. However, applications accessing and working with the registry are platform dependent, which may not always be convenient and it can lead to other problems if the platform is not secure. Therefore, the aim of this work is to create a platform independent application for accessing and working with registry, which makes possible to analyse the effect of malware on registry.
92	Cathode Erosion and Propellant Injection System of a Low-Voltage, Liquid-Fed Pulsed Plasma Thruster Brian Francis Jeffers (15410255) 04 May 2023 (has links) <p>Prior to the mid-20th century, the idea of electric propulsion had been all but a foreign one that manifested itself in the topic of science fiction. It was around this time when companies and agencies like NASA began to take interest in the topic of space propulsion, as most famously seen in the landing of the Apollo 11 mission on the moon. It was not until the early-1960s where the idea of a pulsed plasma thruster was first realized, with its first test being in 1964 aboard the Russian Zond-2 satellite which contained 6 ablative Polytetrafluoroethylene (PTFE, or “Teflon”) pulsed plasma thrusters.</p> <p>In this paper, a new low-voltage, liquid-fed pulsed plasma thruster was developed, tested, and characterized. This project took influence from the previous low-voltage, liquid-fed pulsed plasma thruster in Purdue’s EPPL and desired to transition it from a current gas-fed system to its intended liquid-fed system. The two main objectives for this project included conducting direct studies of the cathode’s erosion rate using a simple weighing method after simulating a lifetime of discharging the thruster, and completing the initial design of the liquid-fed pulsed plasma thruster using AF-M315E as its propellant while gathering data on its required breakdown voltage, exhaust velocity, and specific impulse.</p> <p>Both objectives were successfully completed, with the following parameters being measured or calculated. The required breakdown voltage was seen to be less than 26kV to keep the ignition spark inside the chamber. For the subsequent results measured however, the breakdown voltage was kept between 10-16kV for all successive tests. The peak current measured for all discharges was an average of 11kA, far exceeding similar geometries such as MPD thrusters. The operational voltage was less than 200V, although an operational voltage closer to 100V is expected after further optimization of the system is completed. The erosion rate of the tungsten cathode at this operational setting was found to be 15.4046 +/- 0.592 microgram/Coulomb which is much less than the cathode spot erosion rate reported for tungsten in literature of about 60 microgram/Coulomb and is beneficial for extending system lifetime. The exhaust velocity was calculated to be 30.6 +/- 4.8km/s which is typical of state-of-the-art PPT electric propulsion devices. The specific impulse was also extrapolated from the ion’s exhaust velocity, calculating to be 3,119 +/- 489 seconds. Future work would require optimization of the propellant injection mechanism to minimize propellant loss.</p> Electric propulsion Propulsion Plasma plasma accelerators Plasma Thruster pulsed plasma thruster Magnetoplasmadynamic PPT MPD AF-M315E ASCENT Dual-Mode Low-Voltage Liquid-Fed Pulsed Plasma Thruster LFPPT LF-PPT Erosion Cathode Erosion Electrode Erosion Propellant Injection Liquid Injection EPPL Dr. Shashurin Alex Shashurin Alexey Shashurin Brian Jeffers
93	The Impact of the Lexile Framework on Standardized Literacy Proficiency Scores Gaines, Julia L 24 April 2016 (has links) Upon entering middle school, students within the study district in southeastern Tennessee had low literacy proficiency scores on the Tennessee Comprehensive Assessment Program (TCAP) for 3 consecutive years. Middle school administrators implemented a program called Lexile Framework (LF) into the literacy curriculum in 2011 to improve TCAP scores. However, the change in literacy scores had not been examined following the implementation of LF. The purpose of this quasi-experimental research study was to examine the differences in literacy scores on TCAP of students across the years of pre- and post-LF implementation into the curriculum (2009-2011 and 2012-2014). The theoretical framework for this research study was Vygotsky’s social development theory used within the LF to create student-centered learning in order for students to construct new knowledge by making connections with their literacy experiences. With a convenience sample of 225 students, a repeated-measure analysis of variance determined if there was a significant change in the archived matched literacy TCAP scores before and after the implementation of LF. The multivariate tests indicated a significant (Wilk’s Λ = .21, F (3, 222) = 276.85, p < .01) and linear effect (F (1, 224) = 709.75, p < .01) with partial eta squared (η2 = .76) of LF on literacy TCAP scores of students across the years of pre- and post-LF implementation. Positive social change implications include providing school administrators with research findings to inform district-wide decisions regarding the use of LF in the curricula in their middle schools. Increasing students’ literacy TCAP scores may ultimately improve graduation rates for students. Lexile Framework Literacy Standardized Literacy Proficiency Scores Validation of Reading Interventions Educational Methods Elementary Education and Teaching Higher Education Administration Higher Education and Teaching Scholarship of Teaching and Learning Secondary Education and Teaching Special Education Administration Special Education and Teaching Urban Education
94	Atrial Fibrillation Detection Algorithm Evaluation and Implementation in Java / Utvärdering av algoritmer för detektion av förmaksflimmer samt implementation i Java Dizon, Lucas, Johansson, Martin January 2014 (has links) Atrial fibrillation is a common heart arrhythmia which is characterized by a missing or irregular contraction of the atria. The disease is a risk factor for other more serious diseases and the total medical costs in society are extensive. Therefore it would be beneficial to improve and optimize the prevention and detection of the disease. Pulse palpation and heart auscultation can facilitate the detection of atrial fibrillation clinically, but the diagnosis is generally confirmed by an ECG examination. Today there are several algorithms that detect atrial fibrillation by analysing an ECG. A common method is to study the heart rate variability (HRV) and by different types of statistical calculations find episodes of atrial fibrillation which deviates from normal sinus rhythm. Two algorithms for detection of atrial fibrillation have been evaluated in Matlab. One is based on the coefficient of variation and the other uses a logistic regression model. Training and testing of the algorithms were done with data from the Physionet MIT database. Several steps of signal processing were used to remove different types of noise and artefacts before the data could be used. When testing the algorithms, the CV algorithm performed with a sensitivity of 91,38%, a specificity of 93,93% and accuracy of 92,92%, and the results of the logistic regression algorithm was a sensitivity of 97,23%, specificity of 93,79% and accuracy of 95,39%. The logistic regression algorithm performed better and was chosen for implementation in Java, where it achieved a sensitivity of 97,31%, specificity of 93,47% and accuracy of 95,25%. / Förmaksflimmer är en vanlig hjärtrytmrubbning som kännetecknas av en avsaknad eller oregelbunden kontraktion av förmaken. Sjukdomen är en riskfaktor för andra allvarligare sjukdomar och de totala kostnaderna för samhället är betydande. Det skulle därför vara fördelaktigt att effektivisera och förbättra prevention samt diagnostisering av förmaksflimmer. Kliniskt diagnostiseras förmaksflimmer med hjälp av till exempel pulspalpation och auskultation av hjärtat, men diagnosen brukar fastställas med en EKG-undersökning. Det finns idag flertalet algoritmer för att detektera arytmin genom att analysera ett EKG. En av de vanligaste metoderna är att undersöka variabiliteten av hjärtrytmen (HRV) och utföra olika sorters statistiska beräkningar som kan upptäcka episoder av förmaksflimmer som avviker från en normal sinusrytm. I detta projekt har två metoder för att detektera förmaksflimmer utvärderats i Matlab, en baseras på beräkningar av variationskoefficienten och den andra använder sig av logistisk regression. EKG som kommer från databasen Physionet MIT används för att träna och testa modeller av algoritmerna. Innan EKG-signalen kan användas måste den behandlas för att ta bort olika typer av brus och artefakter. Vid test av algoritmen med variationskoefficienten blev resultatet en sensitivitet på 91,38%, en specificitet på 93,93% och en noggrannhet på 92,92%. För logistisk regression blev sensitiviteten 97,23%, specificiteten 93,79% och noggrannheten 95,39%. Algoritmen med logistisk regression presterade bättre och valdes därför för att implementeras i Java, där uppnåddes en sensitivitet på 91,31%, en specificitet på 93,47% och en noggrannhet på 95,25%. Atrial Fibrillation AF Detection algorithm AF detection Algorithm evaluation Matlab Java Electrocardiogram ECG Heart rate variability HRV Signal processing Pre processing Noise reduction Baseline wander powerline interference wavelet transform DWT R-peak detection Pan-tompkins HRV cleaning Feature selection U-test SDANN SDNN CV RMSSD PNN50 TINN LF HF Logistic regression CV algorithm Receiver operating characteristics ROC Classification Confusion matrix Leave-one-out cross validation Statgraphics Förmaksflimmer detekteringsalgoritm evaluering Matlab Java elektrokardiogram EKG Hjärtfrekvens variabilitet Signalbehandling Brusreducering Logistisk regression Variationskoefficient Klassificering Medical Engineering Medicinteknik

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