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There is a clear need for testing targeted drug carrier systems in a more realistic microenvironment where both biochemical interactions and shear forces are present. This is critical both for understanding of the molecular mechanisms involved in this process and during the drug discovery process. Current in vitro models of the leukocyte adhesion cascade cannot be used for real-time studies of the entire leukocyte adhesion cascade including rolling, adhesion and migration in a single assay. In this study, we have developed and validated a novel bioinspired microfluidic device (bMFD) and used it to test the hypothesis that blocking of specific steps in the adhesion/migration cascade significantly affects other steps of the cascade. The bMFD consists of an endothelialized microvascular network in communication with a tissue compartment via a 3 µm porous barrier. Human neutrophils in bMFD preferentially adhered to activated human endothelial cells near bifurcations with rolling and adhesion patterns in close agreement with in vivo observations. Treating endothelial cells with monoclonal antibodies to E-selectin or ICAM-1 or treating neutrophils with wortmannin reduced rolling, adhesion, and migration of neutrophils to 60%, 20% and 18% of their respective control values. Antibody blocking of specific steps in the adhesion/migration cascade (e.g. mAb to E-selectin) significantly downregulated other steps of the cascade (e.g. migration). This novel in vitro assay provides a realistic human cell based model for basic science studies, identification of new treatment targets, selection of pathways to target validation, and rapid screening of candidate agents. / Mechanical Engineering

It has been recognized for some years that the use of computer graphics systems has great potential for improving man/computer communication. In the past, however, the high cost of graphics hardware, and the lack of accepted principles for graphics programming, prevented the widespread use of such systems. Recently, hardware has become more readily available, and efforts have been made to develop graphics software standards. This report presents an overview of one of the proposed standards, the Core System, and also discusses a portable subroutine library, based on the the Core System, that has been developed for use at McMaster University. This library, called SSOCS, is written in Pascal, and allows a user to produce two-dimensional images without regard to the characteristics of the graphics devices being used. / Thesis / Master of Science (MS)

In this research, we aimed to develop thin-film devices on a polymer substrate and an alternative 3D-printed device with macroelectrodes for treating gastrointestinal (GI) conditions. First, the fabrication of thin-film devices was demonstrated on a softening thiol-ene/acrylate polymer utilizing titanium nitride (TiN) as electrode material. This was achieved by utilizing cleanroom fabrication processes such as photolithography, wet and dry etching. The functionality of the device was shown by performing electrochemical characterization tests, mainly cyclic voltammetry, electrochemical impedance spectroscopy, and voltage transient. We synthesized a novel thiol-ene/acrylate polymer based on 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATATO), trimethylolpropanetris (3-mercaptopropionate) (TMTMP), and polyethylene glycol diacrylate (PEGDA). We show that this stretchable shape memory polymer substrate is well suited for cleanroom processes. Finally, for the high throughput of the wearable devices with electrodes size 10 mm in diameter, we implemented single electrode fabrication using printed circuit boards (PCBs) and depositing gold (Au) and TiN on the plated side of PCBs utilizing the sputtering tool. This step was followed by the assembly of those single electrodes on the flexible 3D printed device. We showed that the TiN electrode material performed better in terms of charge storage capacity and charge injection capacity than the widely used stainless steel electrode material for wearables.

The use of systems that span many knowledge domains is becoming more common as technology advances, requiring expert-performance in a domain from users who are usually not experts in that domain. This study examined a means of communicating expertise (in system operation and fault diagnosis) to non-experts and furthering the understanding of expert mental models. It has been suggested that conceptions of abstract models of system-functions distinguish expert performance from non-expert performance (Hanisch, Kramer, and Hulin, 1991). This study examined the effects on performance of augmenting a simple control panel device with a model of the functions of the device, interacting with the model, and augmenting the device with graphically superimposed procedural indicators (directions). The five augmented display conditions studied were: Device Only, Device + Model, Device + Procedural Indicators, Interactive Model, and Interactive Model + Procedural Indicators. The device and displays were presented on a PC workstation. Performance measures (speed and accuracy) and subjective measures (questionnaires, NASA TLX, and structured interviews) were collected. It was expected that participants who interact with the device + procedural indicators would exhibit the shortest performance time and least errors; however, those who interacted with the simplest display (device only) were fastest and exhibited the least errors. Results of this study are discussed in terms of building a mental model and identifying situations that require a mental model. / Ph. D.

With the increasing speed of the microprocessor and its rapidly increasing demand for power, determining how to power the microprocessors for our computers becomes an important issue. So far, industry has been struggling to operate the VR/VRM at higher and higher switching frequencies while maintaining acceptable power conversion efficiency. As a consequence, the power switches used in the VR/VRM must be able to work efficiently at a higher switching frequency and with a higher current density. To evaluate the performance of the MOSFET for this low-output-voltage, high-current and high-switching-frequency application, a prevalent criterion, the Figure-of-Merit (FOM), is being widely adopted for determining the top switch of the buck converter in the VR/VRM. By comparing the FOMs of different devices, the device with the lowest FOM value should have the best performance and lead to the lowest loss for this device in the circuit. Qgd*Rdson is a widely accepted and widely used FOM for power devices. Due to the lack of accuracy of the power loss model, this FOM is no longer suitable for VRM applications. Furthermore, the question of how to use this FOM to select the right device for different application is another important issue. This work presents an investigation of a new Figure-of-Merit based on a more accurate loss model, which includes the factor of Qgs2, the gate-driving voltage and the packaging parasitics. Furthermore, a simple method is proposed to select the right device and gate-driving voltage for different circuit conditions. A new simple and accurate closeform model for device loss with packing parasitics is derived. This model can provide more physical information for each of the device parameters. The loss influence of the different packaging method is analyzed and discussed at the end of the work. / Master of Science

As farmers continue to get older, they will likely face age-related disabilities that impede their ability to work and increase risk of suffering serious injuries. One of the major age- related diseases is arthritis, which currently accounts for about 40% of disability cases in agriculture nationwide. The effect of arthritis on farmers is profound because it reduces their physical strength, joint range of motion and is a source of joint pain, all culminating in the lack of ability to perform routine activities regularly and safely. One way to decrease the rate of injuries is by reducing the strength and joint loading required to perform these activities through the use of wearable robotics. As opposed to existing solutions that focus only on injury prevention, this thesis will present an active, knee-assist exoskeleton intent on providing 30% of the necessary joint rotation force to perform activities such as sit-to- stand actions and the ascent/descent of stairs and hills. The device will be a lightweight, unobtrusive cable-driven exoskeleton actuated by distally-worn electric motors. We hope that use of the exoskeleton will result in increased ranges of motion and overall reduction of stress on the wearer's body, which will minimize the effects of arthritis and ultimately improve safety and quality of life. / Master of Science / As farmers continue to get older, they will likely face age-related disabilities that impede their ability to work and increase risk of suffering serious injuries. One of the major age-related diseases is arthritis, which currently accounts for about 40% of disability cases in agriculture nationwide. The effect of arthritis on farmers is profound because it reduces their physical strength, joint range of motion and is a source of joint pain, all culminating in the lack of ability to perform routine activities regularly and safely. One way to decrease the rate of injuries is by reducing the strength and joint loading required to perform these activities through the use of wearable robotics. As opposed to existing solutions that focus only on injury prevention, this thesis will present an active, knee-assist exoskeleton intent on providing 30% of the necessary joint rotation force to perform activities such as sit-to-stand actions and the ascent/descent of stairs and hills. The device will be a lightweight, unobtrusive cable-driven exoskeleton actuated by distally-worn electric motors. We hope that use of the exoskeleton will result in increased ranges of motion and overall reduction of stress on the wearer’s body, which will minimize the effects of arthritis and ultimately improve safety and quality of life.

As time progresses, small mobile devices become more prevalent for both personal and industrial use, providing malicious network users with new and exciting venues for security exploits. Standard security applications, such as Norton Antivirus and MacAfee, require computing power, memory space, and operating system complexity that are not present in small mobile devices. Recently, the Battery-Sensing Intrusion Protection System (B-SIPS) was devised as a means to correct the inability of small mobile devices to protect themselves against network attacks. The B-SIPS application uses smart battery data in conjunction with process and network information to determine whether the mobile device is experiencing a battery depletion attack. Additionally, B-SIPS provides mobile device statistics to system administrators such that they can analyze the state of the wireless network more thoroughly. The research presented in this thesis collaborates with and extends the B-SIPS research through optimizations and validation. Areas of focus include ensuring public acceptance of the application through the implementation of a usability study and verifying that the deployment of the application will not jeopardize the performance of external mobile device applications. Additionally, this thesis describes how GUI optimizations are realized for both the B-SIPS client and CIDE server, how future smart battery hardware implementations are introduced for increased effectiveness with the B-SIPS application, and it discusses how an optimum deployment data transmission period is determined. / Master of Science

Embedded sensors are a fixture of most devices in the current computer industry. These small devices are used for a variety of purposes throughout many fields to collect whatever kind of information is needed by the user. From data on device acceleration to data on position relative to the Earth's magnetic field, embedded sensors can provide it for any number of tasks. The advent of these devices has made work and research in the computer industry significantly easier but they are not without their drawbacks. Most of these sensors operate by drawing external data from the environment through send and receive signals. This mode of operation leaves them vulnerable to external malicious users who seek access to the data being stored and handled by the sensors. Concerns over security and privacy of embedded sensor data has become a topic of great concern with the continued digitization of sensitive personal data. Within the last five years, studies have shown the ability to manipulate embedded magnetic sensors in order to gain access to various forms of sensitive personal data. This is of great concern to the developers of mobile devices as most mobile devices possess embedded magnetic sensors. The vulnerability of sensors to external influence leads to concerns for both data privacy and degradation of public trust in the ability of their devices to keep their personal information safe and out of the wrong hands. Degradation of public trust in security methodologies is a major concern to many in the research and tech industry as much of the work conducted to advance both security and technology depends on large amounts of public data. If the public loses trust in the ability of the devices used by researchers to protect and ensure the safety of the data provided to them, then they may stop providing data which would then make the work of researchers and other tech workers considerably more difficult. To address these concerns, this thesis will present an introduction to Magnetic sensor devices (a prominent tool for data collection), how these sensors work and the ways they handle data. We shall then examine the techniques used to interfere with the functioning and output of magnetic sensors employed by mobile devices. Finally, we shall examine existing techniques for defending against these kinds of attacks as well as propose potential new techniques. The end goal of this work is to provide a broader perspective on the nature of environmental/natural interference and its relationship to scientific study and technological advancement. Literature around this topic does exist, however, all existing works currently in the literature focus exclusively on one form of interference i.e., light which leads to a smaller/narrower perspective which this work seeks to remedy. The end result is meant to give a broader perspective of multiple forms of interference and their interrelations between each other than is possible by current perspectives due to their narrow lens. / Master of Science / Embedded sensors are small devices integrated into many mobile devices currently in the public market. These devices serve to collect environmental data of all kinds in order to perform a variety of functions. From directional calibration to magnetic orientation in relation to the magnetic north pole, sensors perform it all. This has led to a massive increase in computer power and quality of life for the general public but not without issue. The increase in storing personal/sensitive data to be processed by these devices has prompted a new breed of privacy concerns and problems to confront. In this thesis, we seek to show the influence and effects of five distinct types of interference rooted in the natural world on the functioning of magnetic sensor devices. Through the experiments conducted in this work, it was found that the interference forms of sound, temperature, and electromagnetism could induce a 32-36 percent average decrease in standard deviation in the data being processed by the sensor. Temperature shifting as an interference form also showed the potential for sizeable impacts on sensor functioning in terms of both increases and decreases. The largest decrease in standard deviation observed was 122 percent from the experiments with low temperature shifting. This work shows the incredible power and influence that the forces of nature can have on everyday devices and their need for data from their environment. The results observed from the temperature shift experiments also highlight the danger of leaving temperature based cyber-attacks under researched. The main use of this work is to fill the void in the current literature created by temperature based cyber-attacks and hopefully spur more research to be conducted into this method of cyber threat.