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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

Characteristics of nearside car crashes : an integrated approach to side impact safety

Sunnevång, Cecilia January 2016 (has links)
Introduction: Approximately 1.25 million people globally are killed in traffic accidents yearly. To achieve the UN Global Goal of a 50% reduction of fatal and serious injuries in 2020 a safer infrastructure, as well as new safety technologies, will be needed. Side crashes represent 20% of all serious and 25 % of fatal injuries. The overall aim of this thesis is to provide guidelines for improved side impact protection. First, by characterizing nearside crashes and injury outcome, including injuries from the farside occupant, for non-senior and senior front seat occupants. Second, to determine whether the WorldSID dummy provides opportunities for improved in-crash occupant protection. And third, by relating in-crash occupant protection to pre-crash countermeasures, to explore a holistic approach for side crashes using the integrated safety chain from safe driving to crash. Methods: NASS/CDS data for both older and modern vehicles was used to provide exposure, incidence, and risk for fatal injury as well as detailed injury distribution and crash characteristics. The WorldSID dummy was compared to Post Mortem Human Subjects (PMHS) in impactor tests at high and low severities to demonstrate the possibilities of this tool. Crash tests were performed to evaluate WorldSID crash test dummy assessments of injuries found in the NASS/CDS data. The integrated safety chain was used to demonstrate how to evaluate occupant protection in side crashes from a larger perspective, involving infrastructure and Automated Emergency Braking. Result: Most side crashes occur at intersections. The head, thorax, and pelvis are the most frequently injured body regions, and seniors have a higher risk for rib fractures compared to non-seniors. The WorldSID dummy response was similar to the PMHS response at the higher impact speed, but not at the lower. In conjunction with improved airbags infrastructural change, and the use of Automated Emergency Braking, can effectively reduce the number of fatalities and injured occupants in side impacts. Conclusion: Future focus for side impact protection should be on intersection crashes, improved occupant protection for senior occupants, and protection for and from the farside occupant, reducing injury risk to the head, thorax, and pelvis. The WorldSID dummy has the ability to reproduce humanlike responses in lateral and oblique impacts. However, at a low crash severity, chest deflection could be underestimated, which must be taken into consideration when evaluating, for example, pre-crash inflated side airbags. Analyzing nearside crashes using the integrated safety chain shows that speed management by means of roundabouts is an efficient countermeasure reducing the number of injurious crashes, as well as reducing variations in crash severity. In combination with an Automated Emergency Braking a large part of side crashes could be avoided or crash severity mitigated. Rather than developing structures and airbags for high-speed crashes, it is important to consider alternative countermeasures. Hence the need for an integrated approach to side impacts.
32

Effect of Cyclosporin and Amlodipine on growth and collagen production of human gingival fibroblasts

Varnfield, Marlien 29 March 2006 (has links)
Drug-induced gingival overgrowth is a disfiguring condition that is a side effect encountered in susceptible responder patients common to three groups of drugs - immunosupressants, calcium channel blockers and anticonvulsant agents. The altered overgrown gingiva can be aesthetically displeasing but in severe cases it can cause functional problems and such patients may eventually require excision of excess tissue. The underlying mechanisms that mediate drug-induced gingival overgrowth is uncertain and the various investigations into the pathogenesis of this disease suggest that it is multifactorial. This study investigated the effects of exogenous addition of cycJosporin and amlodipine on the growth and proliferation of human gingival fibroblasts and the production of collagen by these cells. Results showed that these drugs have a direct stimulatory effect on the gingival fibroblasts of responder patients in vitro and there seems to be a synergistic effect between the two drugs. Findings of this study have important relevance as it suggests that fibroblast proliferation and collagen production must play a significant role in the pathogenesis of drug-induced gingival overgrowth. / Dissertation (MSc (Odontology))--University of Pretoria, 2006. / Dental Management Sciences / unrestricted
33

An Efficiency Evaluation of Far-Field Electromagnetic Deep Learning Side-Channel Attacks in Controlled Environments

Evensen, Gabriel January 2022 (has links)
As more and more modern systems and products use built-in microcontrollers, hardware security becomes more important to protect against cyber-attacks. Internet of things devices, like Bluetooth devices, usually use an encryption algorithm to keep data safe from hackers. Advanced Encryption Standard (AES) is a commonly used encryption algorithm. AES itself is hard to break. However, it is possible to utilize the information leaking from a system during the execution of encryption, called side-channel, to recover the key or part of the key used by the encryption algorithm. This kind of attack is called a side-channel attack (SCA). In this study, two deep learning (DL) models are trained to attack the Bluetooth microcontroller unit Nordic nRF52 development kit equipped with an nRF52832 chip. The DL models are trained using the far-field electromagnetic emissions that the microcontroller unintentionally generates and transmits through the antenna while encrypting data. All encryptions are executed with a fixed key and random plaintext. The attack is conducted in two stages: the profiling and attack stages. In the profiling stage, where the attacker is assumed to have full system control, 100 000 traces holding encryption information are sampled and used to train the DL models to classify a sub-byte of the fixed key given a trace. In the attack stage, traces are captured in two different environments. The first is an entirely isolated environment, while the second adds a specific Wi-Fi access point and client connection that execute HTTP requests and responses in this isolated environment referred to as the system environment. Given traces obtained from one of the two attack environments, the performance of the trained models at classifying the correct sub-key is evaluated.  To summarize the results of this study, twelve SCAs are performed on six datasets captured in two different environments using two different DL models for each dataset. The correct key byte can be retrieved in three of these SCAs. All three successful attacks are made in an isolated environment without any interfering noise. The best performance is achieved with the multi-layer perceptron DL architecture, processing traces each composed of 10 averaged traces of the identical encryption, and the correct key-byte is recovered after 8198 traces.
34

Identifying and understanding the historical extent of side channels on the Missouri River

Hook, Lisa January 1900 (has links)
Master of Arts / Department of Geography / Melinda Daniels / The US Army Corps of Engineers (USACE) has begun side channel restoration projects on the Missouri River as part of the Missouri River Recovery Program. The USACE acquires land on the Missouri River needed to develop fish and wildlife habitat. There is a need to prioritize which land to purchase on the Missouri River. High priority land would be areas that had side channels and can be constructed to restore ecosystems to a more natural state. Much of the river has since been dammed, straightened, and channelized starting heavily in the mid 1890’s, and historical side channels have been eliminated, leaving little information to guide USACE efforts to restore them. My thesis documents the historical distribution of side channels on the Missouri River between St. Louis and Kansas City and explores the relationships between side channel location and a variety of potential driving variables, including channel sinuosity, valley width, valley slope and the presence of large confluences. This is the first know study to document the historical extent of side channels on a major river system, and it is also the first to quantitatively explore driving variables of side channel formation. The historical analysis revealed abundant side channels in the late 1800’s, with a dramatic decline into the early 1920’s as engineering works on the river began in earnest. Results also show that high channel sinuosity and the presence of a large confluences are the two variables most correlated with side channel formation. Based on documented frequencies and locations of historical side channels, recommendations for specific side channel restoration opportunities are also highlighted.
35

Low level aureomycin contamination in a pelleted pony ration

Burch, Lonie L January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
36

A network-based asynchronous architecture for cryptographic devices

Spadavecchia, Ljiljana January 2006 (has links)
The traditional model of cryptography examines the security of the cipher as a mathematical function. However, ciphers that are secure when specified as mathematical functions are not necessarily secure in real-world implementations. The physical implementations of ciphers can be extremely difficult to control and often leak socalled side-channel information. Side-channel cryptanalysis attacks have shown to be especially effective as a practical means for attacking implementations of cryptographic algorithms on simple hardware platforms, such as smart-cards. Adversaries can obtain sensitive information from side-channels, such as the timing of operations, power consumption and electromagnetic emissions. Some of the attack techniques require surprisingly little side-channel information to break some of the best known ciphers. In constrained devices, such as smart-cards, straightforward implementations of cryptographic algorithms can be broken with minimal work. Preventing these attacks has become an active and a challenging area of research. Power analysis is a successful cryptanalytic technique that extracts secret information from cryptographic devices by analysing the power consumed during their operation. A particularly dangerous class of power analysis, differential power analysis (DPA), relies on the correlation of power consumption measurements. It has been proposed that adding non-determinism to the execution of the cryptographic device would reduce the danger of these attacks. It has also been demonstrated that asynchronous logic has advantages for security-sensitive applications. This thesis investigates the security and performance advantages of using a network-based asynchronous architecture, in which the functional units of the datapath form a network. Non-deterministic execution is achieved by exploiting concurrent execution of instructions both with and without data-dependencies; and by forwarding register values between instructions with data-dependencies using randomised routing over the network. The executions of cryptographic algorithms on different architectural configurations are simulated, and the obtained power traces are subjected to DPA attacks. The results show that the proposed architecture introduces a level of non-determinism in the execution that significantly raises the threshold for DPA attacks to succeed. In addition, the performance analysis shows that the improved security does not degrade performance.
37

BROADLEAF WEED CONTROL IN SEEDLING FIELDS OF SIDEOATS GRAMA AT VARIOUS STAGES OF DEVELOPMENT.

AL-MASHHDANY, SHOWKET ABDULLAH. January 1982 (has links)
Two varieties of sideoats grama (Vaughn and NM-28) were planted in late summer of 1980. The seedlings were treated with a variety of broadleaf weed control treatments at 1-, 3-, 5-leaf, and tillering stages of grass seedling growth to determine the effectiveness of these treatments for controlling weeds and the appropriate stages of grass seedling growth to apply them and consequently on grass establishment, density, forage production and plant height. Four months after seeding, NM-28 stands were more dense, produced more forage and the plants were taller than Vaughn. Treatments of dicamba at 0.28 and 0.56 kg/ha were the most effective herbicidal treatments in controlling weeds and resulted in highest stand densities and yields when applied at the 1- and 3-leaf seedling growth. Both treatments gave over 90% control of weeds at the earlier stages but control decreased at later stages of treatment. Lower control resulted when 2,4-D at 0.56 and 1.12 kg/ha were applied. Even though hand weeding treatment resulted weed-free plots during the first four months of seedling development, it resulted in less stand densities and yields when compared to herbicidal treatments. One year after treatment, Vaughn established into taller stands and produced higher yields than NM-28. Dicamba 0.28 kg/ha and 2,4-D 0.56 kg/ha effectively aided in better stand density and yield. Treatments applied at earlier stages of growth resulted in better establishment of both varieties. Dicamba at 0.28 kg/ha was the most effective herbicidal treatment for both varieties. However, hand weeding evaluated one year after seeding, effectively increased both accessions' yield and was the most effective treatment. Greenhouse and laboratory experiments were conducted to determine the uptake and distribution of ('14)C-2,4-D in both sideoats grama accessions and palmer amaranth seedling plant parts at 1, 4, 8 and 24h after treatment. Over all harvest times, 25.3, 2.8 and 3.1% activity were recovered in Vaughn treated leaf, tillers and crown, respectively. That was compared to 33.9, .68 and 6.8% in the same NM-28 plant parts, respectively. Higher percentages of activity were recovered in palmer amaranth plant parts; 50.5% in treated leaf, 8.5% above treated leaf and 5.4% below.
38

GENERATION OF HALOTHANE INDUCED ANTIBODY IN GUINEA PIGS AND ITS POSSIBLE ROLE IN THE PATHOGENESIS OF HALOTHANE INDUCED LIVER INJURY

Siadat Pajouh, Majid, 1959- January 1986 (has links)
No description available.
39

SAR modelling for ecological applications

Darling, Paul Simon January 1998 (has links)
No description available.
40

Analysis and prediction of protein-protein recognition

Betts, Matthew James January 1999 (has links)
No description available.

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