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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.
91

Utvärdering och vidareutveckling av STAPL för användning inom inbäddad Boundary-Scan-baserad test

Holmqvist, Johan January 2007 (has links)
Antalet kretskort som monteras i multikortssystem, till exempel telekommunikationssystem, ökar ständigt. Samtidigt som ytmonteringstekniken och packningstekniken blir allt bättre utvecklas även tillverkningsmetoderna för olika integrerade komponenter, vilket medför att varje kretskort rymmer allt fler integrerade komponenter. Detta gör att testning av integrerade komponenter och multikortsystem blir alltmer komplex. En förutsättning för att kunna genomföra effektiv testning är standarder. Standarder över hur testning ska genomföras medför att en komponent som uppfyller kraven från en standard är direkt utbytbar mot en komponent från en annan tillverkare som uppfyller kraven från samma standard. En god standard bidrar även till att utvecklingen drivs åt samma håll istället för att varje tillverkare har sin egen lösning och ett eget gränssnitt, vilket dessutom leder till att ett antal olika gränssnittsomvandlare behövs för att koppla samman olika komponenter. Internal Joint Test Action Group (IJTAG) arbetar just nu med att ta fram en standard för inbäddade testinstrument på mikronivå. De inbäddade instrumenten kan stödja karaktärisering av komponenter likväl som strukturell och funktionell testning. På makronivå arbetar System Joint Test Action Group (SJTAG) med att ta fram en standard för testadministration. Den främsta uppgiften är att koppla samman IJTAG-standarden med systemtestadministrationen. Behovet av ett kommunikationsprotokoll mellan dessa båda är stort. I denna rapport utvärderas Standard Test and Programming Language (STAPL) i syfte att se hur det passar som länk mellan testmanager och inbäddade instrument. Vidare identifieras ett antal brister i STAPL och ett förslag på en vidareutveckling av språket tas fram. Denna vidareutveckling syftar till att göra språket mer dynamiskt och passande för inbäddad testning via Boundary-Scan-protokollet. Slutligen implementeras en demonstrator som består av mjukvara som exekveras på en PC och en Field Programmable Gate Array (FPGA) som tjänar som testobjekt.
92

Software Vulnerability Assessment : local search methods / Undersökning av sårbarhet i Mjukvara : lokala söknings metoder

Martinsson, Roy January 2006 (has links)
In this thesis, we analyse different ways of detecting application vulnerabilities on installed software. Based on this research, a prototype will be developed that will validate these findings. The prototype will analyse only known vulnerabilities collected from a database and matched with locally collected data.
93

Comparing Optical Coherence Tomography Radial and Cube Scan Patterns for Measuring Bruch’s Membrane Opening Minimum Rim Width (BMO-MRW) in Glaucoma and Healthy Eyes: Cross-sectional and Longitudinal Analysis

Kabbara, Sami 02 April 2018 (has links)
A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Background and Significance: Spectral Domain-Optical Coherence Tomography (OCT) is one of the most widely used imaging modality in Ophthalmology. It utilizes light waves to visualize the various layers of the retina. The OCT machines offer two different scan patterns, the circular and the cube scan patters. It is important to compare these scan pattern to see if any discrepancy exist in quantifying retinal indices. One of the newer indices is the Bruch’s membrane opening minimum rim width (BMO-MRW), which is the minimum distance between from the BMO to the inner limiting membrane (ILM). The BMO-MRW is being used in the diagnosis of glaucoma. Hypothesis: To compare the cube and radial scan patterns of the SD-OCT for quantifying the BMO-MRW. We hypothesis that there might be some differences between the two scan patterns.
94

Investigating circuits underlying acetylcholine-evoked striatal dopamine release in health and disease

Kosillo, Polina January 2014 (has links)
Dopamine (DA) is a key striatal neuromodulator central to normal functioning of the basal ganglia. Identifying and characterizing circuits governing striatal DA transmission is necessary for understanding DA involvement in adaptive behaviour and pathology. Properties of evoked striatal DA release can be examined using fast-scan cyclic voltammetry at carbon fibre microelectrodes, a technique enabling live monitoring of transmitter release events with sub-millisecond resolution. Experimental work presented in this thesis employed this approach to study regulation of striatal DA by acetylcholine (ACh) in health and disease in acute brain slices. Synchronous activity in a small population of striatal cholinergic interneurons (ChIs) was previously shown to directly drive striatal DA release. Here using optogenetic approach I explore physiological relevance of ChI-evoked drive of striatal DA by examining whether corticostriatal and thalamostriatal afferents to ChIs can trigger ACh-evoked DA events. Following floxed vector injections in motor cortex or caudal intralaminar thalamus of CaMK2a-Cre mice I examine the properties of evoked DA upon light activation of channelrhodopsin-2-transduced inputs to striatal ChIs. These experiments revealed that both cortical and thalamic afferents are capable of driving ACh-evoked DA release, but operate using a different complement of post-synaptic ionotropic glutamate receptors and display distinct release recovery profiles. I further explore if rebound excitation in a population of striatal ChIs could drive DA events by examining whether ACh-evoked DA release follows optical inhibition of striatal ChIs selectively expressing hyperpolarizing halorhodopsin 3.0 or archaerhodopsin 3.0 in ChAT-Cre mice. This work showed that hyperpolarizing ion pumps were not successful in triggering ChI-evoked DA release. I also investigate whether cholinergic brainstem innervation of striatum could contribute to or drive ACh-evoked striatal DA events in ChAT-Cre rat, concurrently showing that ChI-evoked DA release is not a species artefact, and is present in mouse and rat alike. Current results also suggest that cholinergic brainstem afferents do not drive or contribute to striatal ACh-evoked DA events. Close interaction between DA and ACh systems further indicates that ACh could impact dopaminergic dysfunction. To explore this I examined the state of ACh transmission in a mouse model of Parkinson’s disease overexpressing human wild type alpha–synuclein protein. These animals present with impaired striatal DA release from young age, but DA deficits could be mediated by changes in ACh tone. Here I show that impaired striatal DA release is the results of primary DA axon dysfunction, although in ventral striatum DA release deficits could be partially compensated by increased ACh tone at nicotinic receptors. I further show that the functional state of muscarinic ACh receptors in not altered following decreased DA transmission, although the data from aged animals suggest that alpha–synuclein-dependent changes in vesicle handling could contribute to impaired DA releasability. Finally, I show that vesicle handling may indeed be altered in this mouse model as impaired DA release is evident with short stimulation protocols, while with prolonged depolarization of DA axon terminals alpha–synuclein-overexpressor mice are better able to sustain evoked DA release. Overall, the main body of work presented in this thesis examined the processes regulating striatal DA transmission via ACh system. In particular, I show that ChI-evoked drive of striatal DA release can be recruited physiologically and further establish that changes in ACh transmission are not the primary drivers of impaired DA releasability in a mouse model of Parkinson’s disease overexpressing human alpha–synuclein protein.
95

Post-operative computed tomography scans in severe cervicofacial infections

Ngcwama, Yanga January 2015 (has links)
Magister Scientiae Dentium - MSc(Dent) / Purpose: To assess the value of postoperative CT scans in the management of severe cervicofacial infections or deep neck abscesses. Patients and Methods: Thirteen patients underwent post-operative contrast enhanced CT scans after initial incision and drainage followed by a tracheostomy. As per surgical protocol, the CT scans were taken with radiopaque surgical drains in situ from the brain down to the mediastinum and chest/lungs. Data were collected on the presence of abscesses, their location, the location of surgical drains and presence of other pathology. Results: The most common initially affected space was the submandibular space (69%), followed by the submental space (62%). Almost half of the cases studied had two spaces affected and slightly less than a third had three spaces affected. Slightly more than half (54%) of the patients were in good health generally. More than a third (38.5%) of the patients were HIV positive, and thus immuno-compromised. The mean time lapse between the CT and surgery was 2.61 days (SD = 1.56). In the majority (69.23%) of post-operative scans a residual pus collection was found. In just over a quarter (30.8 %) of the patients no residual pus collection was detected on the postoperative CT scan, while in seven patients (53.8%) affected fascial spaces were missed by the surgeon. These spaces included the submasseteric, anteriormediastinum and parotid spaces. Almost half (44.15%) of the patients required a repeatincision and drainage. Conclusion: This study demonstrates clinical value of post-operative CT scans in severe cervicofacial infections. This study also advances the argument for acquisition of preoperative CECT scans for all patients with severe cervicofacial infection.
96

Risk based assessment of subsynchronous resonance in AC/DC systems

Adrees, Atia January 2014 (has links)
This thesis investigates the phenomenon of subsynchronous resonance (SSR) in meshed series compensated AC/DC systems in the presence of operational uncertainties. The main contribution of this research is the novel application of risk assessment methods to SSR studies. In terms of network topology, future electric power transmission networks alongside the current power networks are expected to be meshed, and consequently, exposed to relative low risk of subsynchronous resonance. However, power systems are increasingly operated closer to stability limits in order to enhance efficiency and economics of their use. These stressed operating conditions may contribute to the deterioration in the system reliability. Uncertainty associated with the loads will also further diversify in the future due to new type of devices connected to the network whilst the integration of stochastic renewable generation sources will add another layer of uncertainty to system operation. There is a growing necessity to explore the challenges created by the increased uncertainty in generation and loads, and quantify risk to keep a balance between avoiding potentially catastrophic systems failures and mitigating for extremely rare event. This research work introduces risk assessment in subsynchronous resonance studies. Two indices are developed to quantify the severity of dynamic instability and transient torque amplification. Using these indices generators in the network can be ranked based on potential exposure to SSR. Following the development of indices, a methodology is proposed to evaluate the risk of SSR. The developed methodology takes into account the severity of SSR problem and probabilities of different contingencies and different operating conditions of a turbine generator. A robust investigation, into the effect of uncertainties on both aspects of SSR with symmetrical and asymmetrical compensation schemes, is also performed. The results of the analysis reveal that a critically compensated system in normal meshed network configuration may become dynamically unstable with as low as ±5% uncertainty in mechanical parameters. The critical compensation level with asymmetrical compensation in normal network configuration and each contingency becomes higher. It is also shown that the risk level assessed with the developed methodology does not change under the influence of ±5% uncertainties in the mechanical parameters. After establishing, that risk, based approach provides a better picture of all credible scenarios and risk of SSR in compensated power network, a methodology based on risk evaluation of SSR for selecting an optimal combination of TCSCs and fixed series capacitors for compensation of transmission lines is presented. This proposed methodology maximizes the use of fixed capacitors whilst maintaining the risk of SSR within an acceptable level in all credible contingencies and operating conditions.
97

Experimental and numerical analysis of the dynamic load distribution in a corrugated packaging system

Jamialahmadi, Arsalan January 2008 (has links)
It is well known that transportation means high and varying loads for products as well as packages. To develop corrugated boxes with optimal design and efficient use of raw materials is crucial. Vibrations and shocks acting on pallets during transportation are transferred to the corrugated boxes and considerably reduce the integrity and life time of the boxes. The development of experimental and analytical tools for measurement and prediction of the influence of dynamic loads on the box performance, such as stacking strength and conservation of stacking pattern would therefore be of large practical importance. In order to develop such tools, it is important to know the load distribution between different boxes. This master thesis presents a technique for investigating these stresses based on a pressure sensitive film, which gives many data points. A series of tests using random and sinusoidal vibration testing have been done utilising this technique and results are presented for different positions on the pallet and for different box filling methods. Investigations performed on the vibrations of the boxes also demonstrate a pitch type of motion. A level-crossing study on the forces existing between the boxes shows a Rayleigh force distribution. A mathematical model is also proposed for simulation of a stacking system. Advantages and disadvantages with this technique and with the model are described. Comparison between the experimental and numerical results shows a proper correlation. Using the pressure sensitive film as a quantitative sensor and applying the recorded data for the statistical study of the contact forces existing in a stack of boxes gives useful and important results for further analysis of the fatigue life and vulnerable positions of boxes.
98

Novel Electroanalytical Approaches for Investigating the Dynamic Release of Guanosine Ex Vivo

Cryan, Michael January 2021 (has links)
No description available.
99

The effect of Woody Breast Disease on behavior in broiler chickens

Ross, Lauren S. January 2019 (has links)
No description available.
100

Defect Detection Microscopy

Rogers, Stuart Craig 02 September 2010 (has links) (PDF)
The automotive industry's search for stronger lighter materials has been hampered in its desire to make greater use of Magnesium alloys by their poor formability below 150°C. One current challenge is to identify the complex structure and deformation mechanisms at work and determine which of these are primary contributors to the nucleation of defects. Orientation Imaging Microscopy has been the most accessible tool for microstructural analysis over the past 15 years. However, using OIM to analyze defect nucleation sites requires prior knowledge of where the defects will occur because once the defects nucleate the majority of microstructural information is destroyed. This thesis seeks to contribute to the early detection of nucleation sites via three mechanisms: 1. Detection of cracks that have already nucleated, 2. Detection of surface topography changes that may indicate imminent nucleation and 3. Beam control strategies for efficiently finding areas of interest in a scan. Successive in-situ OIM scans of a consistent sample region while strain is increased, while using the three techniques developed in this thesis, will be employed in future work to provide a powerful defect analysis tool. By analyzing retrieved EBSD patterns we are able to locate defect / crack sites via shadowing on the EBSD patterns. Furthermore, topographical features (and potentially regions of surface roughening) can be detected via changes in intensity metrics and image quality. Topographical gradients are currently only detectable in line with the beam incidence. It is therefore suggested that the tensile specimens to be examined are orientated such that the resulting shear bands occur preferentially to this direction. The ability to refine the scan around these areas of interest has been demonstrated via an off-line adaptive scan routine that is implemented via the custom scan tool. A first attempt at a defect detection framework has been outlined and coded into MATLAB. These tools offer a first step to accessing the information about defect nucleation that researchers are currently seeking.

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