Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 110-115).

Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

Currently available upper-limb prostheses do not meet the needs or aspirations of the amputee. Many technical challenges have been given as the limiting factors on the further development of these prostheses. Generally developments have occurred as incremental developments on three existing moderately successful archetypes; the cosmetic, body-powered and myoelectric prostheses. Continued development on these archetypes appears to be further separating prostheses into those primarily considered cosmetic and those primarily considered functional. However, amputees have a need both for function and cosmesis from their prostheses. Technology currently being developed for actuation and control in other laboratories indicates that the previous limitations placed on prosthesis design may be challenged. Therefore, it is appropriate to look for new design archetypes. This thesis describes the development, implementation and evaluation of mechanical analogies of the skeletal components of the human hand and arm which have the potential to inform the design of a new generation of upper-limb prostheses integrating cosmesis and function in a single device. The research has been undertaken using a form of practice led design research methodology. This iterative methodology uses physical models for both evaluation and also as a means of encouraging end-user involvement in the design process. These evaluations are then used in subsequent cycles of research activity. The research has concentrated on developing mechanical analogies of the joints of the hand, wrist, forearm and elbow. The joints of the hand are shown to have a simple and similar structure. Therefore, a modular mechanical archetype has been elucidated that results in a hand configuration made from multiple similar modules positioned at different points throughout the hand. However, the wrist and forearm contain more complex joints which have been found to be unique to their anatomical position. The selection of appropriate prototyping techniques has been an integral part of the research. Problems have arisen in assessing the degree of analogy achieved because the intact joints of the human skeleton are covered by soft tissue that has not been part of the skeletal analogy implemented. Additionally, it is postulated that there are subtleties to human movement which are not reflected in standard anthropometric measures. Therefore, a two stage evaluation has been undertaken that assesses the quality of the analogy realised in the models. This consists of goniometric measures to quantify basic angular rotations whilst qualitative evaluations by professionals with a good anatomical knowledge have been used to assess the more subtle movements within the joints. The skeletal mechanical analogy developed through this research has been shown through evaluation to simulate the articulations of the human upper-limb. The model embodies design principles that appear to have short and long term significance to the field of prosthetics. The production of a tangible model has not only aided evaluation but has also stimulated research in other centres into ways of actuating and controlling a future upper-limb prosthesis. Additionally, the mechanical analogy may have applications in the field of telepresence robotics, aerospace and the entertainment industry.

A series of cruises was made over 14 months to determine the effect of physical transport on the zooplankton of Indian Arm, whose deep water is separated from the marine influence of the Strait of Georgia by a series of shallow sills. The dominant transport process during the study period was tidal exchange. The topographic features of the inlet, coupled with density stratification found over the year, restricted the exchange of water and plankton to a surface phenomenon. Four copepod species were sampled using horizontally towed Clarke-Bumpus nets and vertically towed SCOR nets and one meter conical nets. These were analysed to determine the relationship between different life history patterns and tidal exchange, and the effect of this relationship on the populations of these species inside Indian Arm. Corycaeus anglicus is a surface water to mid depth organism found in highest numbers in Vancouver Harbour. The population density reaches a peak in the fall and remains high throughout the winter with transport concomittant with this peak. Euchaeta japonica exhibits ontogenetic depth preferences, nauplii and Stage I copepodites are found mainly in deep water below 200 meters, Stages II-IV are found mainly in shallow water, and Stages V and VI (adults) are found scattered over most of the water column. This species reproduces throughout the year in both Indian Arm and the Strait of Georgia. Euchaeta japonica was transported mainly as the Stage III copepodite and primarily during the winter months despite the fact that the species is found in surface waters in large numbers at other times of the year, thus producing an isolated population in Indian Arm during the summer. Metridia pacifica is a strong diel migrator found extensively in the upper 50 meters at night, and from 250 meters to 50 meters during the day. Transport of the species across the sill occurs at all times of the year but is significantly greater at night, regardless of the phase of tide. Eucalanus bungi is an ontogenetic migrator, overwintering in deep water (greater than 150 meters), and coming to the surface in the spring to spawn; juvenile stages are found in surface waters during the summer. The data show that this species is transported only during the summer while it is in surface water. Consequently nauplii and younger copepodites are the dispersal stages. The data suggest that the species does not reproduce in Indian Arm and that transport of the species during the summer months can account for the entire overwintering population found in the inlet. An analysis of the correlation of changes in the zooplankton community with physical parameters varying over the tidal cycle was made. Species known to migrate dielly show significant differences in numbers between day and night samples. Relatively few species show differences which can be correlated to the direction of tidal movement. The most significant changes seen in the zooplankton community occur in association with changes in hydrographic properties. Moreover, these changes are manifested not at the species level, but at the community level as changes in such parameters as diversity and dominance. The effect of transport on the zooplankton community in Indian Arm varies from species to species. Qualitatively, the effect depends upon the organisms' life cycle including a surface dwelling stage, and/or its ability to survive the surface water transport conditions. Quantitatively, the effect depends on the amount of time spent in surface water, which varies with the depth distribution of the organism, determined by its behavioral characteristics. The overall effect of tidal exchange will be to drive towards equilibrium the population of zooplankton found in Indian Arm and the Strait of Georgia. It is the biology of the individual species which determines the extent of interaction with this transport process and hence the amount of exchange which takes place. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

ARM is becoming more popular in desktops and data centers. This opens a new realm in terms of security attacks against ARM, increasing the importance of having an effective and efficient defense mechanism for ARM. ARM has released Pointer Authentication, a new hardware security feature that is intended to ensure pointer integrity with cryptographic primitives. Recently, it has been found to be vulnerable. In this thesis, we utilize Pointer Authentication to build a novel scheme to completely prevent any misuse of security-sensitive pointers. We propose PACTight to tightly seal these pointers from attacks targeting Pointer Authentication itself as well as from control-flow hijacks. PACTight utilizes a strong and unique modifier that addresses the current issues with PAC and its implementations. We implement four defenses by fully integrating with the LLVM compiler toolchain. Through a robust and systemic security and performance evaluation, we show that PACTight defenses are more efficient and secure than their counterparts. We evaluated PACTight on 30 different applications, including NGINX web server and using real PAC instructions, with an average performance and memory overhead of 4.28% and 23.2% respectively even when enforcing its strongest defense. As far as we know, PACTight is the first defense mechanism to demonstrate effectiveness and efficiency with real PAC instructions. / M.S. / ARM is slowly but surely establishing itself in the market for desktops and data centers. Intel has been the dominant force for some time but ARM’s entrance into that realm opens up new avenues and possibilities for security attacks against ARM machines. Thus, it is becoming increasingly important to develop an effective and efficient defense mechanism for ARM against possible security threats, particularly against memory corruption vulnerabilities. Memory corruption vulnerabilities are still very prevalent in today’s security realm and have been for the past thirty years. Different hardware vendors have developed a variety of hardware features to combat them and ARM is no different. ARM has released Pointer Authentication, a new hardware security feature that is intended to ensure pointer integrity with cryptographic primitives. Pointer Authentication allows developers to utilize the unused bits of a pointer and add a cryptographic hash that can ensure the pointer hasn’t been tampered with. Pointer Authentication has been utilized in other solutions by security researchers. However, these solutions are either incomplete in their coverage or lack enough randomness for the cryptographic hash. In this thesis we utilize Pointer Authentication to build a novel scheme to completely prevent any misuse of security-sensitive pointers in memory corruption attacks. This thesis presents PACTight to tightly seal these pointers from attacks abusing the limited randomness of the hash as well as control-flow hijack attacks. PACTight implements four defenses by fully integrating with the LLVM compiler toolchain. Through a robust and systemic security and performance evaluation, this thesis show that PACTight defenses are more efficient and secure than their counterparts.

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Telemanipulators allow a user to interact with a potentially dangerous environment remotely. Deploying a robot arm from a UAV would allow an operator to reach farther and quicker than he or she would with a ground robotics system alone. This thesis will discuss the design and fabrication of a compact, light, 3 degree of freedom robot arm using common off the shelf products and machined components that in combination can pick up half pound samples and has a reach of 260 mm. Also addressed is making the telemanipulator interface easier to use. One of the challenges in using a robot arm with a single camera in a beyond line-of-sight scenario is the difficulty of interacting with the environment because of a loss of depth information. This lack of information can be remedied with additional sensors. Once depth to an object of interest is known, the sampler can automatically pick up objects of interest. The manipulator arm will be used in conjunction with systems developed by the Unmanned Systems Laboratory at Virginia Tech. This group is developing a unmanned ground vehicle to be carried in the payload pod of a unmanned aerial vehicle. The robot's ultimate objective is to collect shrapnel and bomb material from potentially dangerous environments. / Master of Science

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