Computer Engineering Commons^™

Exploring Eye Tracking Data On Source Code Via Dual Space Analysis, Li Zhang

School of Computing: Dissertations, Theses, and Student Research

Eye tracking is a frequently used technique to collect data capturing users' strategies and behaviors in processing information. Understanding how programmers navigate through a large number of classes and methods to find bugs is important to educators and practitioners in software engineering. However, the eye tracking data collected on realistic codebases is massive compared to traditional eye tracking data on one static page. The same content may appear in different areas on the screen with users scrolling in an Integrated Development Environment (IDE). Hierarchically structured content and fluid method position compose the two major challenges for visualization. We present a …

Asymptotic Orthogonal Space Shift Keying In Massive Mimo Systems, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications

We investigate space shift keying, which is a simple form of spatial modulation. The bit error rate performance of line-of-sight (LOS) multiple-input and multiple-output (MIMO) was obtained in the literature with orthogonal subchannels for indoor millimeter-wave (mmWave) communications. It is essential to impose a rigid restriction on the distance between the transmitter and the receiver and antenna spacing to maintain orthogonal subchannels. However, in wireless communications, it is not viable to meet the strict distance requirements since user equipment is portable. We propose asymptotic orthogonal space shift keying with mobile stations. The asymptotic orthogonal space shift keying approaches orthogonal subchannels …

Dimensional Analysis Of Robot Software Without Developer Annotations, John-Paul W. Ore

School of Computing: Dissertations, Theses, and Student Research

Robot software risks the hazard of dimensional inconsistencies. These inconsistencies occur when a program incorrectly manipulates values representing real-world quantities. Incorrect manipulation has real-world consequences that range in severity from benign to catastrophic. Previous approaches detect dimensional inconsistencies in programs but require extra developer effort and technical complications. The extra effort involves developers creating type annotations for every variable representing a real-world quantity that has physical units, and the technical complications include toolchain burdens like specialized compilers or type libraries.

To overcome the limitations of previous approaches, this thesis presents novel methods to detect dimensional inconsistencies without developer annotations. We …

Absorptive/Transmissive Frequency Selective Surface With Wide Absorption Band, Qingxin Guo, Jianxun Su, Zengrui Li, Lamar Y. Yang, Jiming Song

Department of Electrical and Computer Engineering: Faculty Publications

An absorptive/transmissive frequency selective surface (ATFSS) with absorption bands at both sides of a passband is presented. Equivalent circuits of the ATFSS that consists of a lossy frequency selective surface (FSS) and a lossless FSS were modeled. To improve the rejection at an undesired band, a transmission zero was introduced and controlled by loading the lossless FSS with four-legged loaded slots. The parasitic passband was suppressed when the cross structure in the lossless FSS was loaded with resistance. In order to expand the absorption band, loaded dipoles were utilized for the lossy FSS design. An ATFSS with wide absorption bands …

The Design And Implementation Of Aida: Ancient Inscription Database And Analytics System, M. Parvez Rashid

School of Computing: Dissertations, Theses, and Student Research

AIDA, the Ancient Inscription Database and Analytic system can be used to translate and analyze ancient Minoan language. The AIDA system currently stores three types of ancient Minoan inscriptions: Linear A, Cretan Hieroglyph and Phaistos Disk inscriptions. In addition, AIDA provides candidate syllabic values and translations of Minoan words and inscriptions into English. The AIDA system allows the users to change these candidate phonetic assignments to the Linear A, Cretan Hieroglyph and Phaistos symbols. Hence the AIDA system provides for various scholars not only a convenient online resource to browse Minoan inscriptions but also provides an analysis tool to explore …

Fiber Optic Bolometer, Ming Han, Matthew L. Reinke

Department of Electrical and Computer Engineering: Faculty Publications

The present disclosure is directed to a fiber optic bolometer device . In an implementation , a fiber optic bolometer device includes an optical fiber and a silicon layer that comprises a Fabry - Perot interferometer . The silicon layer includes a first surface and a second surface . The fiber optic bolometer device includes a reflective dielectric film disposed over the first surface of the silicon layer where the reflective dielec tric film is adjacent to an end face of the optical fiber . The fiber optic bolometer device also includes an absorptive coating disposed over the second surface …

User Privacy Leakage In Location-Based Mobile Ad Services, Qicheng Lin

School of Computing: Dissertations, Theses, and Student Research

The online advertising ecosystem leverages its massive data collection capability to learn the properties of users for targeted ad deliveries. Many Android app developers include ad libraries in their apps as a way of monetization. These ad libraries contain advertisements from the sell-side platforms, which collect an extensive set of sensitive information to provide more relevant advertisements for their customers. Existing efforts have investigated the increasingly pervasive private data collection of mobile ad networks over time. However, there lacks a measurement study to evaluate the scale of privacy leakage of ad networks across different geographical areas. In this work, we …

Scheduling And Prefetching In Hadoop With Block Access Pattern Awareness And Global Memory Sharing With Load Balancing Scheme, Sai Suman

School of Computing: Dissertations, Theses, and Student Research

Although several scheduling and prefetching algorithms have been proposed to improve data locality in Hadoop, there has not been much research to increase cluster performance by targeting the issue of data locality while considering the 1) cluster memory, 2) data access patterns and 3) real-time scheduling issues together.

Firstly, considering the data access patterns is crucial because the computation might access some portion of the data in the cluster only once while the rest could be accessed multiple times. Blindly retaining data in memory might eventually lead to inefficient memory utilization.

Secondly, several studies found that the cluster memory goes …

A Data Driven Approach To Identify Journalistic 5ws From Text Documents, Venkata Krishna Mohan Sunkara

School of Computing: Dissertations, Theses, and Student Research

Textual understanding is the process of automatically extracting accurate high-quality information from text. The amount of textual data available from different sources such as news, blogs and social media is growing exponentially. These data encode significant latent information which if extracted accurately can be valuable in a variety of applications such as medical report analyses, news understanding and societal studies. Natural language processing techniques are often employed to develop customized algorithms to extract such latent information from text.

Journalistic 5Ws refer to the basic information in news articles that describes an event and include where, when, who, what and why …

Lattice Dynamics Of Orthorhombic Ndgao3, Alyssa Mock, Rafal Korlacki, Sean Knight, Megan Stokey, A. Fritz, Vanya Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A complete set of infrared-active and Raman-active lattice modes is obtained from density functional theory calculations for single-crystalline centrosymmetric orthorhombic neodymium gallate. The results for infraredactive modes are compared with an analysis of the anisotropic long-wavelength properties using generalized spectroscopic ellipsometry. The frequency-dependent dielectric function tensor and dielectric loss function tensor of orthorhombic neodymium gallium oxide are reported in the spectral range of 80–1200 cm⁻¹. A combined eigendielectric displacement vector summation and dielectric displacement loss vector summation approach augmented by considerations of lattice anharmonicity is utilized to describe the experimentally determined tensor elements. All infrared-active transverse and longitudinal …

Lattice Dynamics Of Orthorhombic Ndgao3, A. Mock, Rafal Korlacki, Sean Knight, Megan Stokey, A. Fritz, V. Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A complete set of infrared-active and Raman-active lattice modes is obtained from density functional theory calculations for single-crystalline centrosymmetric orthorhombic neodymium gallate. The results for infraredactive modes are compared with an analysis of the anisotropic long-wavelength properties using generalized spectroscopic ellipsometry. The frequency-dependent dielectric function tensor and dielectric loss function tensor of orthorhombic neodymium gallium oxide are reported in the spectral range of 80–1200 cm⁻¹. A combined eigendielectric displacement vector summation and dielectric displacement loss vector summation approach augmented by considerations of lattice anharmonicity is utilized to describe the experimentally determined tensor elements. All infrared-active transverse and longitudinal …

Your Internet Data Is Rotting, Paul Royster

University of Nebraska-Lincoln Libraries: Faculty Publications

The internet is growing, but old information continues to disappear daily.

Many MySpace users were dismayed to discover earlier this year that the social media platform lost 50 million files uploaded between 2003 and 2015. The failure of MySpace to care for and preserve its users’ content should serve as a reminder that relying on free third-party services can be risky. MySpace has probably preserved the users’ data; it just lost their content. The data was valuable to MySpace; the users’ content less so.

Preserving content or intellectual property on the internet presents a conundrum. If it’s accessible, then it …

Image Processing Algorithms For Elastin Lamellae Inside Cardiovascular Arteries, Mahmoud Habibnezhad

School of Computing: Dissertations, Theses, and Student Research

Automated image processing methods are greatly needed to replace the tedious, manual histology analysis still performed by many physicians. This thesis focuses on pathological studies that express the essential role of elastin lamella in the resilience and elastic properties of the arterial blood vessels. Due to the stochastic nature of the shape and distribution of the elastin layers, their morphological features appear as the best candidates to develop a mathematical formulation for the resistance behavior of elastic tissues. However, even for trained physicians and their assistants, the current measurement procedures are highly error-prone and prolonged. This thesis successfully integrates such …

A Data-Driven Approach For Detecting Stress In Plants Using Hyperspectral Imagery, Suraj Gampa

School of Computing: Dissertations, Theses, and Student Research

A phenotype is an observable characteristic of an individual and is a function of its genotype and its growth environment. Individuals with different genotypes are impacted differently by exposure to the same environment. Therefore, phenotypes are often used to understand morphological and physiological changes in plants as a function of genotype and biotic and abiotic stress conditions. Phenotypes that measure the level of stress can help mitigate the adverse impacts on the growth cycle of the plant. Image-based plant phenotyping has the potential for early stress detection by means of computing responsive phenotypes in a non-intrusive manner. A large number …

Low-Dimensional Materials With Protective Coatings For Applications Under Extreme Conditions, Qiming Zou

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Traditional ceramic-based, conductive materials used under extreme conditions are severely limited due to their conditional electrical conductivity and poor stability under harsh circumstances. Advanced composite structures based on vertically aligned carbon nanotubes (VACNTs) and high-temperature ceramics are expected to address this grand challenge, in which ceramic serves as a shielding layer protecting the VACNTs from the oxidation and erosive environment, while the VACNTs work as a conductor. However, it is still a great challenge to fabricate VACNT/ceramic composite structures due to the limited infiltration of ceramics inside the VACNT arrays. Hence developing a feasible method to infiltrate ceramics into VACNT …

Aerial Base Station Deployment For Post-Disaster Public Safety Applications, Jose Antonio Matamoros Vargas

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Earthquakes and floods are constant threats to most of the countries in the world. After such catastrophes, a rapid response is needed, which includes communications not only for first responders but also for local civilians. Even though there are technologies and specialized personnel for rapid deployment, it is common that external factors will hinder the arrival of help while communication requirements are urgently required. Such communication technologies would aid tasks regarding organization and information dissemination from authorities to the civilians and vice-versa. This necessity is due to protocols and applications to allocate the number of emergency resources per location and …

Gaindroid: General Automated Incompatibility Notifier For Android Applications, Bruno Vieira Resende E Silva

School of Computing: Dissertations, Theses, and Student Research

With the ever-increasing popularity of mobile devices over the last decade, mobile apps and the frameworks upon which they are built frequently change. This rapid evolution leads to a confusing jumble of devices and applications utilizing differing features even within the same framework. For Android apps and devices, representing over 80% of the market share, mismatches between the version of the Android operating system installed on a device and the version of the app installed, can lead to several run-time crashes, providing a poor user experience.

This thesis presents GAINDroid, an analysis approach, backed with a classloader based program analyzer, …

Feasibility And Security Analysis Of Wideband Ultrasonic Radio For Smart Home Applications, Qi Xia

School of Computing: Dissertations, Theses, and Student Research

Smart home Internet-of-Things (IoT) accompanied by smart home apps has witnessed tremendous growth in the past few years. Yet, the security and privacy of the smart home IoT devices and apps have raised serious concerns, as they are getting increasingly complicated each day, expected to store and exchange extremely sensitive personal data, always on and connected, and commonly exposed to any users in a sensitive environment. Nowadays wireless smart home IoT devices rely on electromagnetic wave-based radio-frequency (RF) technology to establish fast and reliable quality network connections. However, RF has its limitations that can negatively affect the smart home user …

A Strategic Audit Of Microsoft Azure, Lee Fitchett

Honors Program: Senior Projects (Public)

This paper looks at Microsoft Azure's current strategies and proposes possible options for the future. It looks at several competitors and explores how Azure will affect and react to Microsoft’s vision.

Phonon Order And Reststrahlen Bands Of Polar Vibrations In Crystals With Monoclinic Symmetry, Mathias Schubert, Alyssa Mock, Rafal Korlacki, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

In this Rapid Communication, we present the order of the phonon modes and the appearance of the reststrahlen bands for monoclinic symmetry materials with polar lattice vibrations. Phonon modes occur in associated pairs of transverse and longitudinal optical modes, and pairs either belong to inner or outer phonon modes. Inner modes are nested within outer modes. Outer modes cause polarization-dependent reststrahlen bands. Inner modes cause polarization-independent reststrahlen bands. The directional limiting frequencies within the Born-Huang approach are bound to within outer mode frequency regions not occupied by inner mode pairs. Hence, an unusual phonon mode order can occur where both …

Phonon Order And Reststrahlen Bands Of Polar Vibrations In Crystals With Monoclinic Symmetry, Mathias Schubert, Alyssa Mock, Rafał Korlacki, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

In this Rapid Communication, we present the order of the phonon modes and the appearance of the reststrahlen bands for monoclinic symmetry materials with polar lattice vibrations. Phonon modes occur in associated pairs of transverse and longitudinal optical modes, and pairs either belong to inner or outer phonon modes. Inner modes are nested within outer modes. Outer modes cause polarization-dependent reststrahlen bands. Inner modes cause polarization-independent reststrahlen bands. The directional limiting frequencies within the Born-Huang approach are bound to within outer mode frequency regions not occupied by inner mode pairs. Hence, an unusual phonon mode order can occur where both …

Jitana: A Modern Hybrid Program Analysis Framework For Android Platforms, Yutaka Tsutano, Shakthi Bachala, Witawas Srisa-An, Gregg Rothermel, Jackson Dinh

School of Computing: Faculty Publications

Security vetting of Android apps is often performed under tight time constraints (e.g., a few minutes). As such, vetting activities must be performed “at speed”, when an app is submitted for distribution or a device is analyzed for malware. Existing static and dynamic program analysis approaches are not feasible for use in security analysis tools because they require a much longer time to operate than security analysts can afford. There are two factors that limit the performance and efficiency of current analysis approaches. First, existing approaches analyze only one app at a time. Finding security vulnerabilities in collaborative environments such …

Femtosecond Photon-Mediated Plasma Enhances Photosynthesis Of Plasmonic Nanostructures And Their Sers Applications, Peng Ran, Lan Jiang, Xin Li, Bo Li, Pei Zuo, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Laser ablation in liquid has proven to be a universal and green method to synthesize nanocrystals and fabricate functional nanostructures. This study demonstrates the superiority of femtosecond laser-mediated plasma in enhancing photoredox of metal cations for controllable fabrication of plasmonic nanostructures in liquid. Through employing upstream high energetic plasma during laser-induced microexplosions, single/three-electron photoreduction of metallic cations can readily occur without chemical reductants or capping agents. Experimental evidences demonstrate that this process exhibits higher photon utilization efficiency in yield of colloidal metal nanoparticles than direct irradiation of metallic precursors. Photogenerated hydrated electrons derived from strong ionization of silicon and water …

Manipulation Of Lipss Orientation On Silicon Surfaces Using Orthogonally Polarized Femtosecond Laser Double-Pulse Trains, Wei Liu, Lan Jiang, Weina Han, Jie Hu, Xiaowei Li, Ji Huang, Shenghua Zhan, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Laser-induced periodic surface structures (LIPSS) provide an easy and costeffective means of fabricating gratings and have been widely studied in recent decades. To overcome the challenge of orientation controllability, we developed a feasible and efficient method for manipulating the orientation of LIPSS in real time. Specifically, we used orthogonally polarized and equal-energy femtosecond laser (50 fs, 800 nm) double-pulse trains with time delay about 1ps, total peak laser fluence about 1.0 J/cm², laser repetition frequency at 100 Hz and scanning speed at 150 μm/s to manipulate the LIPSS orientation on silicon surfaces perpendicular to the scanning direction, regardless …

Growth Of Nitride Films, Yongfeng Lu, Hossein Rabiee Golgir, Yunshen Zhou

Department of Electrical and Computer Engineering: Faculty Publications

A gallium nitride thin film can be formed on a substrate at a low temperature (e.g., not higher than 600°C .) by applying a laser to resonantly excite molecules of a first precursor that contains nitrogen, in which the laser has a wavelength that is selected to match a vibration mode and/or a vibrational rotational mode of the molecules of the first precursor. A second precursor is provided in which the excited first precursor and the second precursor react to form a nitride that is deposited on the substrate. For example, the second precursor may include gallium, and the nitride …

Fabrication Of Highly Homogeneous And Controllable Nanogratings On Silicon Via Chemical Etching-Assisted Femtosecond Laser Modification, Ji Huang, Lan Jiang, Xiaowei Li, Andong Wang, Zhi Wang, Qingsong Wang, Jie Hu, Liangti Qu, Tianhong Cui, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Femtosecond laser direct writing is widely exploited in surface periodic structures processing. However, this technique still faces challenges in obtaining high surface homogeneity and flexible morphology controllability. In this study, a flexible and efficient approach has been proposed to fabricate highly homogeneous and controllable nanogratings on silicon via chemical etching-assisted femtosecond laser modification. By precisely manipulating the laser-material interaction process, alternating amorphous-crystalline nanofringes are generated when employing femtosecond laser scanning over a Si sample, with almost no material removal. Following auxiliary chemical etching, highly homogeneous nanograting structures are obtained, and the morphology of the nanogratings can be flexibly managed through …

Overview Of Extreme Manufacturing, Dongming Guo, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Today we live in a new era of economic globalization and rapid technological growth. The advancement of both our society and standard of living require us to delve into this new world and unleash the possibilities our future. We need to broaden the horizons of our universe to discover a new realm where the future of humanity can flourish. We need to be unafraid to unveil the mysteries hidden within the depths of our oceans to unearth treasures that will benefit not only us, but the generations to come.

Effect Of Titanium And Zirconium Carbide Interphases On The Thermal Conductivity And Interfacial Heat Transfers In Copper/ Diamond Composite Materials, Clio Azina, Inaki Cornu, Jean-Francois Silvain, Yongfeng Lu, Jean-Luc Battaglia

Department of Electrical and Computer Engineering: Faculty Publications

Thermal properties of metal matrix composite materials are becoming ever more relevant with the increasing demand for thermally efficient materials. In this work, the thermal conductivity and heat transfers at the interfaces of copper matrix composite materials reinforced with diamond particles (Cu/D) are discussed. The composite materials contain either ZrC or TiC interphases and exhibit, respectively, higher and lower thermal conductivities with respect to their pure Cu/D counterparts. These thermal conductivities are accounted to the presence of strong covalent bonds and increased relative densities. The role of these interphases is also discussed regarding the phonon transmission at the interfaces.

A Novel Method Of Near-Miss Event Detection With Software Defined Radar In Improving Railyard Safety, Subharthi Banerjee, Jose Santos, Michael Hempel, Pejman Ghasemzadeh, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications

Railyards are one of the most challenging and complex workplace environments in any industry. Railyard workers are constantly surrounded by dangerous moving objects, in a noisy environment where distractions can easily result in accidents or casualties. Throughout the years, yards have been contributing 20–30% of the total accidents that happen in railroads. Monitoring the railyard workspace to keep personnel safe from falls, slips, being struck by large object, etc. and preventing fatal accidents can be particularly challenging due to the sheer number of factors involved, such as the need to protect a large geographical space, the inherent dynamicity of the …

Self-Organized Twist-Heterostructures Via Aligned Van Der Waals Epitaxy And Solid-State Transformations, Peter Sutter, Rina Ibragimova, Hannu-Pekka Kosma, Bruce A. Parkinson, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Vertical van der Waals (vdW) heterostructures of 2D crystals with defined interlayer twist are of interest for band-structure engineering via twist moiré superlattice potentials. To date, twist-heterostructures have been realized by micromechanical stacking. Direct synthesis is hindered by the tendency toward equilibrium stacking without interlayer twist. Here, we demonstrate that growing a 2D crystal with fixed azimuthal alignment to the substrate followed by transformation of this intermediate enables a potentially scalable synthesis of twisted heterostructures. Microscopy during growth of ultrathin orthorhombic SnS on trigonal SnS2 shows that vdW epitaxy yields azimuthal order even for non-isotypic 2D crystals. Excess sulfur drives …