Computer Engineering Commons^™

Continuous Human Activity Tracking Over A Large Area With Multiple Kinect Sensors, Akshat C. Hans

ETD Archive

In recent years, researchers had been inquisitive about the use of technology to enhance the healthcare and wellness of patients with dementia. Dementia symptoms are associated with the decline in thinking skills and memory severe enough to reduce a person’s ability to pay attention and perform daily activities. Progression of dementia can be assessed by monitoring the daily activities of the patients. This thesis encompasses continuous localization and behavioral analysis of patient’s motion pattern over a wide area indoor living space using multiple calibrated Kinect sensors connected over the network. The skeleton data from all the sensor is transferred to …

Using Regular Languages To Explore The Representational Capacity Of Recurrent Neural Architectures, Abhijit Mahalunkar, John D. Kelleher

Conference papers

The presence of Long Distance Dependencies (LDDs) in sequential data poses significant challenges for computational models. Various recurrent neural architectures have been designed to mitigate this issue. In order to test these state-of-the-art architectures, there is growing need for rich benchmarking datasets. However, one of the drawbacks of existing datasets is the lack of experimental control with regards to the presence and/or degree of LDDs. This lack of control limits the analysis of model performance in relation to the specific challenge posed by LDDs. One way to address this is to use synthetic data having the properties of subregular languages. …

Vehicle-To-Barrier Communication During Real-World Vehicle Crash Tests, Samil Temel, Mehmet C. Vuran, Mohammad M.R. Lunar, Zhongyuan Zhao, Abdul Salam, Ronald K. Faller, Cody S. Stolle

School of Computing: Faculty Publications

Vehicle-to-barrier (V2B) communication is expected to facilitate wireless interactions between vehicles and roadside barriers in next-generation intelligent transportation systems. V2B systems will help mitigate single-vehicle, run-off-road crashes, which account for more than 50% of roadside crash fatalities. In this work, the characteristics of the wireless channel prior to and during a crash are analyzed using orthogonal frequency division multiplexing (OFDM) techniques, which has been used in existing vehicular communication systems. More specifically, the performance of OFDM-based V2B links are measured in real-world crash tests for the first time. Three crash tests conducted at the Midwest Roadside Safety Facility, Lincoln, Nebraska, …

Uneven-Layered Coding Metamaterial Tile For Ultrawideband Rcs Reduction And Diffuse Scattering, Jianxun Su, Huan He, Zengrui Li, Yaoqing Lamar Yang, Hongcheng Yin, Junhong Wang

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, a novel uneven-layered coding metamaterial tile is proposed for ultra-wideband radar cross section (RCS) reduction and diffuse scattering. The metamaterial tile is composed of two kinds of square ring unit cells with different layer thickness. The reflection phase difference of 180° (±37°) between two unit cells covers an ultra-wide frequency range. Due to the phase cancellation between two unit cells, the metamaterial tile has the scattering pattern of four strong lobes deviating from normal direction. The metamaterial tile and its 90-degree rotation can be encoded as the ‘0’ and ‘1’ elements to cover an object, and diffuse …

Ultraviolet Laser Photolysis Of Hydrocarbons For Nondiamond Carbon Suppression In Chemical Vapor Deposition Of Diamond Films, Li-Sha Fan, Loic Constantin, Da-Wei Li, Lei Liu, Kamran Keramatnejad, Clio Azina, Xi Huang, Hossein Rabiee Golgir, Yao Lu, Zahra Ahmadi, Fei Wang, Jeffrey E. Shield, Bai Cui, Jean-Francois Silvain, Yong-Feng Lu

Department of Electrical and Computer Engineering: Faculty Publications

In this work, we demonstrate that ultraviolet (UV) laser photolysis of hydrocarbon species alters the flame chemistry such that it promotes the diamond growth rate and film quality. Optical emission spectroscopy and laser-induced fluorescence demonstrate that direct UV laser irradiation of a diamond-forming combustion flame produces a large amount of reactive species that play critical roles in diamond growth, thereby leading to enhanced diamond growth. The diamond growth rate is more than doubled, and diamond quality is improved by 4.2%. Investigation of the diamond nucleation process suggests that the diamond nucleation time is significantly shortened and nondiamond carbon accumulation is …

Optimal Computational Power Allocation In Multi-Access Mobile Edge Computing For Blockchain, Yuan Wu, Xiangxu Chen, Jiajun Shi, Kejie Ni, Liping Qian, Liang Huang, Kuan Zhang

Department of Electrical and Computer Engineering: Faculty Publications

Blockchain has emerged as a decentralized and trustable ledger for recording and storing digital transactions. The mining process of Blockchain, however, incurs a heavy computational workload for miners to solve the proof-of-work puzzle (i.e., a series of the hashing computation), which is prohibitive from the perspective of the mobile terminals (MTs). The advanced multi-access mobile edge computing (MEC), which enables the MTs to offload part of the computational workloads (for solving the proof-of-work) to the nearby edge-servers (ESs), provides a promising approach to address this issue. By offloading the computational workloads via multi-access MEC, the MTs can effectively increase their …

Structure-Mediated Excitation Of Air Plasma And Silicon Plasma Expansion In Femtosecond Laser Pulses Ablation, Qingsong Wang, Lan Jiang, Jingya Sun, Changji Pan, Weina Han, Guoyan Wang, Feifei Wang, Kaihu Zhang, Ming Li, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Femtosecond laser-induced surface structures upon multiple pulses irradiation are strongly correlated with the pulse number,which in turn significantly affects successive laser-material interactions. By recording the dynamics of femtosecond laser ablation of silicon using time-resolved shadowgraphy, here we present direct visualization of the excitation of air plasma induced by the reflected laser during the second pulse irradiation.The interaction of the air plasma and silicon plasma is found to enhance the shockwave expansion induced by silicon ablation in the longitudinal direction, showing anisotropic expansion dynamics in different directions. We further demonstrate the vanishing of air plasma as the pulse number increases because …

Deformation Behavior Of Foam Laser Targets Fabricated By Two-Photon Polymerization, Ying Liu, John H. Campbell, Ori Stein, Lijia Jiang, Jared Hund, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Two-photon polymerization (2PP), which is a three-dimensional micro/nano-scale additive manufacturing process, is used to fabricate component for small custom experimental packages (“targets”) to support laser-driven, high-energy-density physics research. Of particular interest is the use of 2PP to deterministically print millimeter-scale, low-density, and low atomic number (CHO) polymer matrices (“foams”). Deformation during development and drying of the foam structures remains a challenge when using certain commercial acrylic photo-resins. Acrylic resins were chosen in order to meet the low atomic number requirement for the foam; that requirement precludes the use of low-shrinkage organic/inorganic hybrid resins. Here, we compare the use of acrylic …

Bias-Dependent Scanning Tunneling Microscopy Signature Of Bridging-Oxygen Vacancies On Rutile Tio2(110), Willie B. Maddox, Danda P. Acharya, G. Jeremy Leong, Peter Sutter, Cristian V. Ciobanu

Department of Electrical and Computer Engineering: Faculty Publications

The rutile TiO₂(110) surface has long-served as a wellcharacterized, prototypical transition-metal oxide surface used in heterogeneous catalysis and photocatalytic water splitting. Naturally occurring defects on this surface, called bridging-oxygen (BO) vacancies, are important as they determine the overall reactivity of the surface. Herein, we report a bias-dependent, scanning tunneling microscopy (STM) signature of the BO vacancies on TiO₂(110): for sample bias voltages past a threshold of +3 V, the bright vacancies are flanked on either side (along the oxygen row) by two dark spots approximately shaped like half-moons. The BO vacancies have a bright aspect below …

Experimental Analyses On Multiscale Structural And Mechanical Properties Of Ε-Si/Gesi/C-Si Materials, Wei Qiu, Lu-Lu Ma, Hong-Tao Wang, Ren-Rong Liang, Yu-Cheng Zhao, Yun-Shen Zhou

Department of Electrical and Computer Engineering: Faculty Publications

Strained silicon (ε-Si) is a promising material that could extend Moore’s law by enhancing electron mobility. A ε-Si material is usually composed of multiscale, multilayer heterostructures, where the strained-silicon film or strap is tens-of-nanometers thick, and its buffer layers are of the micrometer scale. The structural properties determine the electrical performance and reliability of ε-Si-based devices. Inhomogeneous residual stress is induced during the preparation, which induces ε-Si structure failure. In this work, biaxial strained-silicon films that contain graded and relaxed germanium-silicon buffer layers were prepared on monocrystalline silicon wafers through reduced-pressure chemical-vapor epitaxy. The layer components and thicknesses were measured …

Adaptive Transmission Range Based Topology Control Scheme For Fast And Reliable Data Collection, Haojun Teng, Kuan Zhang, Mianxiong Dong, Kaoru Ota, Anfeng Liu, Ming Zhao, Tian Wang

Department of Electrical and Computer Engineering: Faculty Publications

An Adaptive Transmission Range Based Topology Control (ATRTC) scheme is proposed to reduce delay and improve reliability for data collection in delay and loss sensitive wireless sensor network. The core idea of the ATRTC scheme is to extend the transmission range to speed up data collection and improve the reliability of data collection.The main innovations of our work are as follows: (1) an adaptive transmission range adjustment method is proposed to improve data collection reliability and reduce data collection delay. The expansion of the transmission range will allow the data packet to be received by more receivers, thus improving the …

Integrated Vacuum-Ultraviolet, Mid And Near-Ultraviolet, Visible, Near, Mid And Far Infrared And Terahertz Optical Hall Effect (Ohe) Instrument, And Method Of Use, Tino Hofmann, Mathias M. Schubert, Stefan Schoeche, Philipp Kuehne, Craig M. Herzinger, John A. Woollam, Gregory K. Pribil, Thomas E. Tiwald, Sean R. Knight

Department of Electrical and Computer Engineering: Faculty Publications

Optical Hall Effect (OHE) method for evaluating such as free charge carrier effective mass, concentration, mobility and free charge carrier type in a sample utilizing a permanent magnet at room temperature.

Fiber - Optic Temperature And Flow Sensor System And Methods, Ming Han, Guigen Liu, Weilin Hou

Department of Electrical and Computer Engineering: Faculty Publications

A fiber optic sensor, a process for utilizing a fiber optic sensor, and a process for fabricating a fiber optic sensor are described, where a double-side-polished silicon pillar is attached to an optical fiber tip and forms a Fabry-Perot cavity. In an implementation, a fiber optic sensor in accordance with an exemplary embodiment includes an optical fiber configured to be coupled to a light source and a spectrometer; and a single silicon layer or multiple silicon layers disposed on an end face of the optical fiber, where each of the silicon layer(s) defines a Fabry-Perot interferometer, and where the sensor …

Non-Vacuum Preparation Of Wse2 Thin Films Via The Selenization Of Hydrated Tungsten Oxide Prepared Using Chemical Solution Methods, Christopher L. Exstrom, Scott A. Darveau, Megan E. Falconer, Jessica R. Blum, Whitney M. Colling, Natale J. Ianno

Department of Electrical and Computer Engineering: Faculty Publications

It is known that tungsten oxide may be reacted with selenium sources to form WSe₂ but literature reports include processing steps that involve high temperatures, reducing atmospheres, and/or oxidative pre-treatments of tungsten oxide. In this work, we report a non-vacuum process for the fabrication of compositionally high quality WSe₂ thin films via the selenization of tungsten oxide under milder conditions. Tungsten source materials were various hydrated WO₃ and WO_2.9 compounds that were prepared using chemical solution techniques. Resulting films were selenized using a two-stage heating profile (250 °C for 15 minutes and 550 °C for 30 …

Non-Vacuum Preparation Of Wse2 Thin Films Via The Selenization Of Hydrated Tungsten Oxide Prepared Using Chemical Solution Methods, Christopher L. Exstrom, Scott A. Darveau, Megan E. Flaconer, Jessica R. Blum, Whitney M. Colling, Natale J. Ianno

Department of Electrical and Computer Engineering: Faculty Publications

It is known that tungsten oxide may be reacted with selenium sources to form WSe2 but literature reports include processing steps that involve high temperatures, reducing atmospheres, and/or oxidative pre-treatments of tungsten oxide. In this work, we report a non-vacuum process for the fabrication of compositionally high quality WSe2 thin films via the selenization of tungsten oxide under milder conditions. Tungsten source materials were various hydrated WO3 and WO2.9 compounds that were prepared using chemical solution techniques. Resulting films were selenized using a two-stage heating profile (250 oC for 15 minutes and 550 oC for 30 minutes) under a static …

Mathematically Predicting The Aleut Tribe Population Using Archaeological Data, Jack Conrad Kiefer Ii, Paden Allen Thompson

Research on Capitol Hill

Sanak Island, located off the southern Alaska Peninsula, was home to the native Aleut peoples for thousands of years. Their hunter-gatherer society depended heavily on the arctic and marine ecosystem for food resources.

In 2015, a team of archaeologists from Idaho State and Utah State universities went to the island and collected data about the Aleut population size and their diet.

This study constructed a dynamical model to mathematically predict the Aleut population over time in order to gain insights into how food resources affected the Aleut people’s ability to survive.

Categorical Range Reporting In 2d Using Wavelet Tree, Swathi Kanthareddy Sumithra

Electronic Theses and Dissertations

The research involved optimizing the space and bounding the output time by the output size in categorical range reporting of points within the given rectangle query Q in two dimension using wavelet trees and range counting. The time taken to report those points and space to tore n points in set S can be done using wavelet tree and range counting. Consider set S consisting of n points in two-dimension. An orthogonal range reporting query rectangle Q = [a,b] x [c,d] on set S is sent to report the set of points in S which interacts with the query rectangle[Q]. …

Managing Io Resource For Co-Running Data Intensive Applications In Virtual Clusters, Dan Huang

Electronic Theses and Dissertations

Today Big Data computer platforms employ resource management systems such as Yarn, Torque, Mesos, and Google Borg to enable sharing the physical computing among many users or applications. Given virtualization and resource management systems, users are able to launch their applications on the same node with low mutual interference and management overhead on CPU and memory. However, there are still challenges to be addressed before these systems can be fully adopted to manage the IO resources in Big Data File Systems (BDFS) and shared network facilities. In this study, we mainly study on three IO management problems systematically, in terms …

Cyber Security And Risk Society: Estonian Discourse On Cyber Risk And Security Strategy, Lauren Kook

Copyright, Fair Use, Scholarly Communication, etc.

The main aim of this thesis is to call for a new analysis of cyber security which departs from the traditional security theory. I argue that the cyber domain is inherently different in nature, in that it is lacking in traditional boundaries and is reflexive in nature. Policy-makers are aware of these characteristics, and in turn this awareness changes the way that national cyber security strategy is handled and understood. These changes cannot be adequately understood through traditional understanding of security, as they often are, without missing significant details. Rather, examining these changes through the lens of Ulrich Beck’s risk …

Security Of Autonomous Systems Under Physical Attacks: With Application To Self-Driving Cars, Raj Gautam Dutta

Electronic Theses and Dissertations

The drive to achieve trustworthy autonomous cyber-physical systems (CPS), which can attain goals independently in the presence of significant uncertainties and for long periods of time without any human intervention, has always been enticing. Significant progress has been made in the avenues of both software and hardware for fulfilling these objectives. However, technological challenges still exist and particularly in terms of decision making under uncertainty. In an autonomous system, uncertainties can arise from the operating environment, adversarial attacks, and from within the system. As a result of these concerns, human-beings lack trust in these systems and hesitate to use them …