Doctor of Philosophy, The Ohio State University, 2015, Electrical and Computer Engineering

This dissertation deals with the analysis and control of the modular multilevel converter (MMC) in order to develop a new control method to be used a wide range of submodules per arm. Ultra-high voltage DC (UHVDC) transmission systems are among the most promising systems to transmit power for distances up to 3000 km and ultra-voltage up to 2200 KVDC. One of the most challenging issues associated with UHVDC is the conversion of power at the receiving end of UHVDC transmission systems. This dissertation focuses on a development on Modular Multilevel Converter (MMC) control strategies. Two control methods are proposed, a direct pulse-width modulation (PWM) algorithm and an approximated arm energy control algorithm, MMCs to be used with a large scale of submodules per arm that can convert UHVDC 2200 KV and more to UHVAC, reducing total harmonics distortion (THD) for UHVAC less than 1%. Generating insertion indices for number of submodule per arm (N) in each control method is derived first. Second, flooring switching PWM is explained to generate number of inserted and bypassed submodules per arm. Third, analysis of the balancing of the submodules voltages and submodules selection, the key technique to achieve insertion and equalization between arm submodules, is proposed and verified by simulation and experiment. Fourth, a set of simulation results for DC bus 2200 KV and 481- level for the output voltage conducted in MATLAB/Simulink environment verify the proposed algorithm. Finally, the prototype's hardware design and software design verify the proposed PWM algorithm experimentally. This presentation shows the experimental results.

Committee: Longya Xu Prof. (Advisor); Jin Wang Prof. (Committee Member); Mahesh Illindala Prof. (Committee Member); Junmin Wang Prof. (Committee Member) Subjects: Electrical Engineering

MS, University of Cincinnati, 2014, Engineering and Applied Science: Mechanical Engineering

Hand-Arm Vibration Syndrome (HAVS) collectively refers to diseases associated with prolonged, intensive exposure to hand-transmitted vibrations. Millions of construction workers who use hand-held power tools are affected by HAVS in the United States. Numerous dynamic models of the hand-arm system were developed to better understand the injury mechanism. One of the problems in dynamic response analysis of the hand-arm system has been difficulty in finding the excitation forces generated by the operation of hand-held tools. Especially, the force transmitted to the hands from the tool and the force interacting between the tool and work-piece are very useful information in hand-arm vibration study; however, they cannot be measured directly. Methods to estimate these forces are developed in this work by utilizing a hand-arm model, the acceleration measured at the hand, and two measured transfer functions of the tool. Experimental validation procedures of the methods are devised, which show the estimated forces are accurate enough to be used for practical applications. The method developed in this work enables estimation of the force acting between the tool and workpiece in a hand-held power tool in operation for the first time. There are many potential applications of the method developed in this work. For example, the methods can be used to make design changes in the handle bar of a grinder to reduce vibration transmission to the hands, ultimately leading to a lower frequency of HAVS.

Committee: J. Kim Ph.D. (Committee Chair); Thomas Richard Huston Ph.D. (Committee Member); David Thompson Ph.D. (Committee Member) Subjects: Engineering

Master of Education (MEd), Bowling Green State University, 2010, Human Movement, Sport and Leisure Studies /Kinesiology

Purpose: The purpose of this study was to compare the physiological characteristics and responses of obese and non-obese women to arm ergometry. Some exercises (e.g. walking, cycling, etc.) may be too demanding for obese individuals. Therefore, arm ergometry may be a better exercise in the obese population because it utilizes a smaller muscle mass and is non-weight bearing. This is necessary so that exercise physiologists, physicians, and personal trainers can prescribe individualized exercise programs using the arm ergometer as physical activity in obese individuals who cannot tolerate the stress of other forms of exercise. Methods: Twenty, low risk females aged 18 to 22 years old participated in this study. Anthropometric measurements included were: height, weight, abdominal diameter, arm, waist and hip circumferences, skinfolds, and arm volume. The participants also completed a progressive, continuous, multistage arm ergometry exercise test using a modified Monark cycle ergometer to exhaustion. Oxygen consumption, ratings of perceived exertion, respiratory exchange ratio, ventilation, and heart rate were assessed every minute during the exercise test. Independent-samples t test were calculated. Results: Significant differences were found between the means for the obese and non-obese groups for body weight (kg) t = -5.47, p <.05, df=18, BMI (kg/m2) t = -6.09, p < .05, df =18, body fat % t = -8.25, p <.05, df=18, waist circumference (cm) t = -6.27, p <.05, df=18, hip circumference (cm) t = -5.75, p <.05, df=18, waist to hip ratio t = -2.66, p <.05, df=18, abdominal diameter (cm) t = -6.02, p <.05, df=18, and HRmax (b.min-1) t = -2.15, p <.05, df=18, arm circumference t = -2.9, p<.05, df =18, arm volume t = -3.62, p<.05, df = 18, and upper arm fat mass t = -4.92, p < .05, df = 18 . For VO2 (ml.kg.min-1), a significant interaction was found between Group x Time F = 7.51, p < .0001, df = 5. Differences between the obese and non-obese groups were found at minutes 8, 9, (open full item for complete abstract)

Committee: Lynn Darby PhD (Committee Chair); Amy Morgan PhD (Committee Member); Todd Keylock PhD (Committee Member) Subjects: Anatomy and Physiology; Health; Physical Education

Master of Engineering, Case Western Reserve University, 2013, EECS - System and Control Engineering

ABBY is a mobile industrial manipulator, a mobile robot equipped with an industrial robotic arm. The goal in creating this robot was to demonstrate that a robust research platform for mobile industrial manipulation can be created quickly at low cost. This goal was achieved by leveraging commercially-available mass produced hardware and open source software. The resulting mobile manipulator incorporates a suite of commercially-available sensors and processing hardware to enable the robot to operate as an intelligent agent alongside humans. The robot demonstrated its abilities by performing simple navigation and manipulation tasks in a laboratory setting, and will soon be employed in research on autonomous kitting in industrial environments.

Committee: Gregory Lee PhD (Advisor); Murat Cavusoglu PhD (Committee Member); Roger Quinn PhD (Committee Member) Subjects: Electrical Engineering; Engineering; Industrial Engineering; Robotics; Systems Design

Master of Science in Cyber Security (M.S.C.S.), Wright State University, 2022, Computer Science

Vulnerabilities in source code can be compiled for multiple processor architectures and make their way into several different devices. Security researchers frequently have no way to obtain this source code to analyze for vulnerabilities. Therefore, the ability to effectively analyze binary code is essential. Similarity detection is one facet of binary code analysis. Because source code can be compiled for different architectures, the need can arise for detecting code similarity across architectures. This need is especially apparent when analyzing firmware from embedded computing environments such as Internet of Things devices, where the processor architecture is dependent on the product and cannot be controlled by the researcher. In this thesis, we propose a system for cross-architecture binary similarity detection and present an implementation. Our system simplifies the process by lifting the binary code into an intermediate representation provided by Ghidra before analyzing it with a neural network. This eliminates the noise that can result from analyzing two disparate sets of instructions simultaneously. Our tool shows a high degree of accuracy when comparing basic blocks. In future work, we hope to expand its functionality to capture function-level control flow data.

Committee: Junjie Zhang Ph.D. (Advisor); Lingwei Chen Ph.D. (Committee Member); Meilin Liu Ph.D. (Committee Member) Subjects: Computer Science

PhD, University of Cincinnati, 2022, Engineering and Applied Science: Aerospace Engineering

The aim of this dissertation is to explore the flight and control characteristics of advanced multirotors. This dissertation mainly considers three advanced multirotor designs i) Tilt-rotor quadcopter ii) Re-configurable tilt-rotor quadcopter, and iii) Sliding-Arm Quadcopter system. The traditional multirotors have many structural and operational limitations such as under-actuation, fault-tolerance during flight, disturbance rejection, limited control bandwidth. This dissertation aims to identify and resolve these issues by different hardware and software enhancements. This research addresses the fundamental information gaps in the design of the flight controllers for the tilt-rotor quadcopter. It covers detailed information on the impact of propeller spin configurations on the dynamics and structure of the flight controller. The flying capabilities of the tilt-rotor quadcopter are explored for commanding the UAV to maintain a specified orientation while navigating across the way points. Linearization approach has been utilized to drive an accurate control allocation for the tilt-rotor system. This research also highlights the application of the quaternion state feedback in the attitude controller design for the tilt-rotor quadcopter by eliminating the conventional Euler angle based approach which could cause singularities in the system. In the conventional quadcopters, propeller or motor failure is a primary fault during flight. This research introduces the concept of structural and control reconfiguration in the system where the UAV can continue to fly and complete the flight mission after the failure of one propeller. The structural reconfiguration is achieved by extending the arm length of the quadcopter opposite to the failed rotor in a passive manner. It causes a shift in the center of gravity and the moment of inertia of the system and the tilt-rotor system is converted into a T-Copter. This methodology has shown that the UAV can continue to fly after a motor (open full item for complete abstract)

Committee: Manish Kumar Ph.D. (Committee Member); Rajnikant Sharma Ph.D. (Committee Member); Ou Ma Ph.D. (Committee Member); Kelly Cohen Ph.D. (Committee Member) Subjects: Aerospace Materials

Master of Sciences, Case Western Reserve University, 0, EECS - Computer and Information Sciences

Humanity is expanding its reach into space, underseas, and hostile environments through robotics. It is desired that remote, robotic workers are competent at increasingly sophisticated tasks, including servicing, assembly and manufacturing. A key ingredient in this pursuit is for machines to sense, interpret and respond effectively to contact forces and torques. The present research describes the development and testing of low-level, compliant-motion behaviors for robots performing contact tasks. The behaviors are evaluated in a variety of useful tasks, commanded by a human operator invoking supervisory controls. The approach is shown to be tolerant of communication latencies, and makes the robotic operations inherently safe for the robot and its environment. It is further shown that the human interface is easy to master, and that low-level behaviors can be combined to achieve higher levels of robot autonomy.

Committee: Wyatt Newman (Advisor) Subjects: Computer Science; Robotics; Robots; Systems Design; Technology

Doctor of Philosophy, The Ohio State University, 2021, Computer Science and Engineering

Side-channel attacks are attacks that make use of peripheral information, e.g., timing, power, etc, to infer private information. Recent studies have shown that attackers can learn sensitive information (e.g., cryptographic keys) through side channels, which jeopardizes the user's security and privacy. In this work, we aim to 1) study the recent advances of side-channel attacks on modern platforms (e.g., smartphones), 2) propose mitigation mechanisms to close the network side channels. In particular, to study the side-channel attack vectors on smartphones, first, we present a systematic study of Flush-Reload side-channel attacks on ARM processors and show that the attacks can be constructed in a return-oriented fashion. We also demonstrate practical attacks on Android systems. Second, we present the first exploration of OS-level side channels on iOS, which are side channels exposed by public APIs. We show three categories of side-channel attacks on iOS to demonstrate that iOS is also vulnerable to such attacks. Our proposed mitigations have been integrated into the recent versions of iOS/MacOS. Besides investigating the attack vectors, we also propose defense mechanisms to defeat network side-channel attacks. We show how to adopt adversarial machine learning and differential privacy to defeat streaming traffic analysis attackers.

Committee: Yinqian Zhang (Advisor); Radu Teodorescu (Advisor); Zhiqiang Lin (Committee Member) Subjects: Computer Engineering; Computer Science

Doctor of Philosophy, Case Western Reserve University, 2021, Biomedical Engineering

Cervical level spinal cord injuries often result in paralysis of all four limbs - a condition known as tetraplegia. Tetraplegia severely limits patient independence and quality of life. Previous studies have demonstrated that coordinated functional electrical stimulation (FES) of the neuromuscular system can restore limited motor function to people with tetraplegia. However, to fully restore upper-limb motor function, controllers for FES systems must be able to coordinate the many actuators and many mechanical degrees of freedom of the human upper extremity. Several FES controller architectures have already been identified. However, most of these architectures required patient-specific manual tuning, which may not be practical to perform for all 175,000 people in the United States living with tetraplegia due to spinal cord injuries. Here, I propose an FES controller for the human upper extremity that learns automatically via reinforcement learning without the need for patient-specific manual tuning. I demonstrate that the reinforcement learning controller can quickly learn to control a horizontal planar model of the human arm with high accuracy. In the future, I hope that reinforcement learning controllers will enable efficient and efficacious restoration of motor function to people with spinal cord injuries.

Committee: Robert Kirsch PhD (Advisor); Jonathan Miller MD (Committee Member); Dustin Tyler PhD (Committee Member); Antonie van den Bogert PhD (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Engineering

Master of Science (MS), Wright State University, 2020, Human Factors and Industrial/Organizational Psychology MS

Social interactions are complex and constantly changing decision making environments. Prior research (Mayer, Davis, & Schoorman, 1995) has found that people use their trust in others as a criterion for decision making during social interactions. Trust is not only relevant for human-human interaction, but has also been found to be important for human-machine interaction as well, which is becoming a growing feature in many work domains (De Visser et al., 2016). Prior research on trust has attempted to identify the behavioral characteristics an individual (trustor) uses to assess the trustworthiness of another (trustee) to determine the trustor's level of trust. Experimental findings have been used to develop into various models of trust (Mayer et al., 1995; Juvina, Collins, Larue, Kennedy & de Mello, 2019) to explain how a trustor comes to trust a trustee. An aspect of trust that has not been investigated is how or if trust changes when a trustor attempts to interact with a trustee, but cannot interact with the trustee. Under such situations Juvina et al.'s (2019) trust model makes the novel prediction that trust will decrease. To assess the prediction of Juvina et al. (2019) model, a new experimental design (the multi-arm trust game) was developed to evaluate how trust is affected under conditions where an individual variably interacts with multiple trustees. Additionally, the identity the trustee (human and machine) was manipulated to examine differences between human-human and human-machine trust. Before data were collected, the model made ex-ante predictions of the participants' behavior. The accuracy of these predictions was then evaluated after the data were collected. The results from our experiment found that our model was able to predict general characteristics of the data confirming the necessity of the model's discounting mechanism, while also highlighting model limitations that are areas for future research.

Committee: Ion Juvina Ph.D. (Advisor); Kevin A. Gluck PhD. (Committee Member); Joseph Houpt Ph.D. (Committee Member); Valerie L. Shalin Ph.D. (Committee Member) Subjects: Psychology

Master of Sciences (Engineering), Case Western Reserve University, 2020, EECS - Electrical Engineering

Robots are ideal for work in inhospitable environments. These environments are often far away, under water, or in space, and robots operating there are susceptible to communications lag between the operator and the robot. This results in long missions, which are tedious for robot operators and hard on remote energy sources. Autonomous skills solve this problem. Using a six DOF robotic arm, a six DOF force-torque sensor, Robot Operating System (ROS), and Natural Admittance Control (NAC), skills have been developed that are stable, robust, gentle, and quick. A robot supervisor using these skills can quickly perform assembly tasks such as removing a child-proof medicine bottle cap and inserting a cylinder over a peg even under effort constraints and two second communication lag.

Committee: Wyatt Newman (Advisor); Greg Lee (Committee Member); Cenk Cavusoglu (Committee Member) Subjects: Computer Science; Electrical Engineering; Engineering; Robotics; Robots

Bachelor of Science, Ashland University, 2019, Sport Sciences

Softball pitchers are subjected to repetitive shoulder movements in a single game, and typically, there is minimal rest between games during the season. Repeated muscle damage needs adequate nutrients for repair, especially protein and iron, yet, nutrient requirements are already elevated in this population due to age and gender of the group (Kerksick, Wilborn, Roberts, Smith-Ryan, Kleiner, Jager,…Krieder, 2018; Thane, Bates, & Prentice, 2002; Willows, Grimston, Smith, & Hanley, 1995). This age group is at even greater risk due to potential restricted eating behaviors that would decrease total nutrient intake (Mathias, K., Jacquier, E., Eldridge, A. L., 2015). Developing adolescents experience rapid cellular growth, which demands increased iron in the body. Furthermore, athletic training also increases the demand for iron due to an increase of muscle mass, blood volume, myoglobin, and erythrocyte mass (Willows, Grimston, Smith, & Hanley, 1995). Both adolescent and athletic growth increases the need for iron in the blood, which puts adolescents at an even greater risk of becoming iron deficient. Therefore, they are at greater risk for upper arm impairment and athletic injury if their nutrient intake falls below what their bodies need.

Committee: David Vanata Dr. (Advisor); Denise Reed (Advisor); Christopher Swanson Dr. (Committee Chair) Subjects: Nutrition; Physical Therapy

Doctor of Philosophy (PhD), Wright State University, 2018, Computer Science and Engineering PhD

The world's ageing population has significantly increased over the last decades, which will result in one of the most significant transformations of the twenty-first century. As people age, they become more vulnerable to diseases and their health may need constant monitoring. At the same time, the number of people who have some kind of disability is also increasing. These people with disabilities may need daily assistance and monitoring of their health condition that is provided by specialists (health providers) at a high cost. A possible solution to the aforementioned problem comes from the assistive and intelligent robotics research area. The profound importance of this research area derives from several necessities of the people that belong in these groups when in hospitals or at homes. The most important necessity is to have a more independent life with increased personal autonomy. However, although assistive and intelligent robotics have significantly advanced, they are still far from completely replacing the human provider. In an effort to advance the potential and capabilities of assistive-intelligent robotics, we proposed an intelligent robotic wheelchair that is able to assist people in need. In particular, the system will assist the user to stand up, turn around, sit down or perform rehabilitation exercises. Therefore, the goal of such a system is real time response in assisting users in daily activities with active participation, that leads to quality of life improvement for certain categories of people in need.

Committee: Nikolaos Bourbakis Ph.D. (Advisor); Soon Chung Ph.D. (Committee Member); Yong Pei Ph.D. (Committee Member); Sherry Farra Ph.D. (Committee Member); Miltiadis Alamaniotis Ph.D. (Committee Member) Subjects: Computer Engineering; Computer Science; Mechanical Engineering; Robotics

MS, University of Cincinnati, 2018, Engineering and Applied Science: Aerospace Engineering

Dual-arm robots have several unique capabilities that make them very attractive for many applications, such as task flexibility, and the ability to perform “two-handed” object manipulation tasks that other systems cannot. Additionally, humanoid systems have the ability to access workspaces and use tools designed for humans. However, in order for these dual-arm systems to be utilized in particularly challenging environments – such as human-shared environments, outer space, or disaster zones – these systems will need to become much more capable than they are today. Currently, the control of these systems is made difficult due to their complex planning, dynamics, and control, and current dual-arm robotic systems are nowhere near resilient enough to handle the uncertainty and risk that are found in these use cases. A separate issue (one which is found in other areas of robotics as well) is that the control architectures are seldom shared, and are so specialized and hardcoded to their particular use cases that they cannot be easily reused even when shared. Extensive development effort, therefore, goes into redeveloping new systems for each particular application with limited ability for reuse.

Committee: Catharine McGhan Ph.D. (Committee Chair); Ou Ma Ph.D. (Committee Member); Rajnikant Sharma Ph.D. (Committee Member) Subjects: Robots

Master of Science, Miami University, 2018, Mechanical and Manufacturing Engineering

The study of human-machine interaction is a field with rapidly increasing applications due to the proliferation of cell phones and other mobile devices, and the increase in the number of touch-screen devices has created a need for understanding of how people interact with them. Fitts' Law is a psychological law relating the physical aspects of pointing task completion to its difficulty as determined by movement amplitude and target size. This research seeks to model the biomechanics of this task using a four degree of freedom arm to simulate the completion of pointing tasks in accordance with Fitts' Law using a PID controller. Results were compared with data gathered by the Wright Patterson Air Force Research Laboratory's Human Effectiveness labs under Dr. Leslie Blaha's direction. Preliminary results show similar movement times between the data and simulation, but further refinement of the model is required to match the paths taken. Piecewise gravitational compensation and adaptive control schemes are implemented with mixed results. The effects of parametric adjustments are investigated.

Committee: James Chagdes (Advisor); Timothy Cameron (Committee Member); Giancarlo Corti (Committee Member) Subjects: Mechanical Engineering

Master of Science (MS), Ohio University, 2017, Electrical Engineering & Computer Science (Engineering and Technology)

Body Area Networks are beneficial in many applications including fitness tracking and remote healthcare monitoring. This thesis discusses system enhancements to the award-winning Ohio University Body Area Network system which senses heart rate, integrates an inertial measurement unit, and measures ambient temperature. An upgraded ARM-based Nordic microprocessor was implemented to collect and process biometric sensor data and utilize low-energy Bluetooth (BLE) to transmit data via a Bluetooth antenna. Data is received on an updated Android application running on a handheld Nexus 5 Smartphone. Power received measurements were performed to compare the Baseline and Enhanced systems using several Bluetooth antenna solutions including an e-textile spiral antenna, a traditional inset-fed patch antenna, and a printed monopole antenna.

Committee: Chris Bartone (Advisor); Savas Kaya (Committee Member); Maarten Uijt De Haag (Committee Member); David Drozek (Committee Member) Subjects: Computer Engineering; Electrical Engineering

Master of Science, The Ohio State University, 2017, Mechanical Engineering

This thesis presents the development details of a human safety robotic arm design with variable stiffness, starting from an initial conceptual design to prototype validations. Instead of changing the compliance of the joint, this design concept introduces compliance to the robotic link itself. The mechanism of the design is a parallel guided beam with a slider linear actuated by a power screw and a DC motor. By controlling the slider position, the effective length of the robotic arm link can be adjusted to achieve necessary stiffness change. The stiffness variation capability of the effective length concept was first validated on a physical conceptual model by experiments. For comparison, a simulation model was also created for the structure of the robotic arm in Abaqus using finite element methods. All the analysis, simulation and tests performed in this research were based on small beam bending deflections. A prototype was developed based on the conceptual model, having transmission and actuation module integrated. Simple and accurate PID position control using Arduino for rapid prototyping is also demonstrated in this thesis. The performance of the prototype was evaluated by two categories of experiments: stiffness tests and PID position calibration. The overall stiffness change ratio achieved was around 20 times by static stiffness test results. The position steady state error and the overshoot of the system was within 0.5mm.

Committee: Haijun Su (Advisor); Junmin Wang (Committee Member) Subjects: Mechanical Engineering

Master of Science, University of Akron, 2017, Polymer Science

The objective of the research was to study the effects on surface segregation in binary polymer blends of both chain end functionalization of linear chains, and changes in architecture. An important question for the formation and application of a polymer thin film is the degree to which end group functionalization can influence the segregation of a chain to the air/polymer and polymer/substrate interfaces. For the first part of this study, well-defined polystyrene and hydroxyethylated functionalized polystyrene of exactly the same molecular weight (Mn = 6000 g/mol) were synthesized using anionic polymerization in order to minimize the impact of factors other than end group functionalization in the study of the segregation driven by the functionalization. Thin (90 nm) films of blends of these two chains spun cast on silicon substrates were investigated. Key to the study was use of a new method called Surface Layer Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (SL-MALDI-TOF-MS) which determines the composition at the surface (< 2 nm depth) of entire polymer chains, rather than the segment or chain end composition measured with other techniques. This technique requires no isotopic labeling. The most striking finding is that the surface region is not only depleted in the high energy chain end functionality, but, in fact, depleted in chains containing the functional group. Thus, for the first time, depletion of the entire chain, driven by only a single functionalized end group, was observed directly. The depletion of the surface in functionalized chains varies with composition and is more pronounced for blends of near-symmetric composition. For the study of the effect of architecture on surface segregation, star-branched polymers with two different architectures were synthesized. Well-defined 5.5k 4-arm star was successfully synthesized using a combination of anionic polymerization and silane linking chemistry. The structure (open full item for complete abstract)

Committee: Mark Foster (Advisor); Li Jia (Committee Member) Subjects: Physics; Polymer Chemistry; Polymers

Doctor of Philosophy, The Ohio State University, 2017, Physics

Central to the advancement of many biomedical and nanotechnology capabilities is the capacity to precisely control the motion of micro and nanostructures. These applications range from single molecule experiments to cell isolation and separation, to drug delivery and nanomachine manipulation. This dissertation focuses on actuation of biological micro- and nano-entities through the use of weak external magnetic fields, superparamagnetic beads, and ferromagnetic thin films. The magnetic platform presents an excellent method for actuation of biological systems due to its ability to directly control the motion of an array of micro and nanostructures in real-time with calibrated picoNewton forces. The energy landscape of two ferromagnetic thin film patterns (disks and zigzag wires) is experimentally explored and compared to corresponding theoretical models to quantify the applied forces and trajectories of superparamagnetic beads due to the magnetic traps. A magnetic method to directly actuate DNA nanomachines in real-time with nanometer resolution and sub-second response times using micromagnetic control was implemented through the use of stiff DNA micro-levers which bridged the large length scale mismatch between the micro-actuator and the nanomachine. Compared to current alternative methods which are limited in the actuation speeds and the number of reconfiguration states of DNA constructs, this magnetic approach enables fast actuation (~ milliseconds) and reconfigurable conformations achieved through a continuous range of finely tuned steps. The system was initially tested through actuation of the stiff arm tethered to the surface, and two prototype DNA nanomachines (rotor and hinge) were successfully actuated using the stiff mechanical lever. These results open new possibilities in the development of functional robotic systems at the molecular scale. In exploiting the use of DNA stiff levers, a new technique was also developed to investigate the emergence of the mag (open full item for complete abstract)

Committee: Ratnasingham Sooryakumar (Advisor) Subjects: Physics

Master of Sciences (Engineering), Case Western Reserve University, 2017, EECS - Electrical Engineering

Hand-arm vibration syndrome has been an occupational hazard for a long time. However, a detail understanding of its vibration exposure inset is not yet available, largely because instrumentation for its in situ monitoring has been difficult to implement. With the development of wearable electronics, new solutions for its monitoring and study have become possible. This work studies the usefulness of monitoring vibration magnitude, EMG (electromyography) signal, PPG (photoplethysmogram) signal and finger skin temperature in quantifying continuous hand-arm vibration exposure. A commercial orbital sander was used. The results show that vibration magnitude and median frequency of EMG signal do not lead to better measurements than finger skin temperature and PPG signal for such monitoring. The finger skin temperature decreases 8.8% on average during 25 minutes of vibration exposure and increases 6.2% on average during 15 minutes of rest. The pulsatile component of PPG signal decreases 4.8% and increases 35% on average during vibration and rest, respectively. The non-pulsatile component of PPG signal decreases 28% and increases 5% on average during vibration and rest, respectively. Finger skin temperature and PPG signal can be effective indicators in HAV monitoring but have to be treated carefully.

Committee: Mehran Mehregany (Committee Chair); Michael Fu (Committee Member); Yeongae Heo (Committee Member) Subjects: Biomedical Engineering; Electrical Engineering; Industrial Engineering; Medicine