Computer Engineering Commons^™

Luminescence Of Defects In The Structural Transformation Of Layered Tin Dichalcogenides, Peter Sutter, H.P. Komsa, A. V. Krasheninnikov, Y Huang, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Layered tin sulfide semiconductors are both of fundamental interest and attractive for energy conversion applications. Sn sulfides crystallize in several stable bulk phases with different Sn:S ratios (SnS2, Sn2, S3, and SnS), which can transform into phases with a lower sulfur concentration by introduction of sulfur vacancies (VS). How this complex behavior affects the optoelectronic properties remains largely unknown but is of key importance for understanding light-matter interactions in this family of layered materials. Here, we use the capability to induce VS and drive a transformation between few-layer SnS2 and SnS by electron beam irradiation, combined with in-situ cathodoluminescence spectroscopy …

Tiled Time Delay Estimation In Mobile Cloud Computing Environments, Ruairí De Fréin

Conference papers

We present a tiled delay estimation technique in the context of Mobile Cloud Computing (MCC) environments. We examine its accuracy in the presence of multiple sources for (1) sub-sample delays and also (2) in the presence of phase-wrap around. Phase wrap-around is prevalent in MCC because the separation of acoustic sources may be large. We show that tiling a histogram of instantaneous phase estimates can improve delay estimates when phase-wrap around is sig- nificantly present and also when multiple sources are present. We report that error in the delay estimator is generally less than 5% of a sample, when the …

Load Balancing With Energy Storage Systems Based On Co-Simulation Of Multiple Smart Buildings And Distribution Networks, Shaun Duerr, Cristinel Ababei, Dan M. Ionel

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we present a co-simulation framework that combines two main simulation tools, one that provides detailed multiple building energy simulation ability with Energy-Plus being the core engine, and the other one that is a distribution level simulator, Matpower. Such a framework can be used to develop and study district level optimization techniques that exploit the interaction between a smart electric grid and buildings as well as the interaction between buildings themselves to achieve energy and cost savings and better energy management beyond what one can achieve through techniques applied at the building level only. We propose a heuristic …

Condensation And Subsequent Freezing Delays As A Result Of Using A Femtosecond Laser Functionalized Surface, Chongji Huang

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

Femtosecond laser surface processing (FLSP) enhances the anti-icing properties of a commonly used aircraft alloy, Al 7075-O Clad. The wettability of Al 7075-O Clad was altered by changing the surface morphology through FLSP and the surface chemistry through siloxane vapor deposition. Tall mound and short mound FLSP functionalized surfaces were created through two sets of laser parameters. Atmospheric condensation and subsequent freezing of condensates on FLSP Al 7075-O Clad was studied. Results indicate that both structure height and surface wettability play a role in the delay of freezing. Freezing occurred on the FLSP superhydrophilic surface faster than on a unprocessed …

Anti-Icing Properties Of Femtosecond Laser Surface Processed Material, Ryan James Bell

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

In this thesis, the use of femtosecond laser surface processing (FLSP) to enhance the anti-icing properties of a commonly used aircraft alloy, Al 7075-O Clad is described. By changing the surface morphology through FLSP and the surface chemistry through siloxane vapor deposition, the wettability of Al 7075-O Clad was altered.

Condensation and the subsequent freezing of condensates on FLSP Al 7075-O Clad was studied. Both structure height and surface wettability were shown to play a role in the delay of freezing. Freezing occurred on the FLSP superhydrophilic surface faster than on the unprocessed Al 7075-O Clad surface, however, freezing was …

Classification Of Daily Activities For The Elderly Using Wearable Sensors, Jian Liu, Jeehoon Sohn, Sukwon Kim

Computer Sciences and Electrical Engineering Faculty Research

Monitoring of activities of daily living (ADL) using wearable sensors can provide an objective indication of the activity levels or restrictions experienced by patients or elderly. The current study presented a two-sensor ADL classification method designed and tested specifically with elderly subjects. Ten healthy elderly were involved in a laboratory testing with 6 types of daily activities. Two inertial measurement units were attached to the thigh and the trunk of each subject. The results indicated an overall rate of misdetection being 2.8%. The findings of the current study can be used as the first step towards a more comprehensive activity …

When Will Mems Switches Be Ready For Commercial Products?, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.

Clutter Suppression Via Hankel Rank Reduction For Dfrft-Based Vibrometry Applied To Sar, Francisco Pérez, Balu Santhanam, Ranlf Dunkel, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

Hankel rank reduction (HRR) is a method that, by prearranging the data in a Hankel matrix and performing rank reduction via singular value decomposition, suppresses the noise of a time-history vector comprised of the superposition of a finite number of sinusoids. In this letter, the HRR method is studied for performing clutter suppression in synthetic aperture radar (SAR)-based vibrometry. Specifically, three different applications of the HRR method are presented. First, resembling the SAR slow-time signal model, the HRR method is utilized for separating a chirp signal immersed in a sinusoidal clutter. Second, using simulated airborne SAR data with 10 dB …

Grouping Environmental Factors Influencing Individual Decision-Making Behavior In Software Projects: A Cluster Analysis, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

An individual’s decision-making behavior is heavily influenced by and adapted to external environmental factors. Given that software development is a human-centered activity, individual decision-making behavior may affect the software project quality. Although environmental factors affecting decision-making behavior in software projects have been identified in prior literature, there is not yet an objective and a full taxonomy of these factors. Thus, it is not trivial to manage these complex and diverse factors. To address this deficiency, we first design a semantic similarity algorithm between words by utilizing the synonymy and hypernymy relationships in WordNet. Further, we propose a method to measure …

Working On A Start-Up: A Case For An Applied Entrepreneurship Oriented Course For Senior Undergraduates, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we describe a new teaching approach whose objective is to implement entrepreneurship-based learning. The proposed teaching approach is essentially a project-based approach, but, with two novel key components that give it the entrepreneurship emphasis. First, the main idea is to divide students into groups of four or five members and have each team go through the process of starting-up a company. This process tries to emulate all steps through which entrepreneurs go when a new start-up idea is taken from concept to product realization. These steps include proposing a novel start-up idea, writing a business plan, coming …

An Advanced Three-Level Active Neutral-Point-Clamped Converter With Improved Fault-Tolerant Capabilities, Ramin Katebi, Jiangbiao He, Nathan Weise

Electrical and Computer Engineering Faculty Research and Publications

A resilient fault-tolerant silicon carbide (SiC) three-level power converter topology is introduced based on the traditional active neutral-point-clamped converter. This novel converter topology incorporates a redundant leg to provide fault tolerance during switch open-circuit faults and short-circuit faults. Additionally, the topology is capable of maintaining full output voltage and maximum modulation index in the presence of switch open and short-circuit faults. Moreover, the redundant leg can be employed to share load current with other phase legs to balance thermal stress among semiconductor switches during normal operation. A 25-kW prototype of the novel topology was designed and constructed utilizing 1.2-kV SiC …

Dynamic Energy Management For Chip Multi-Processors Under Performance Constraints, Milad Ghorbani Moghaddam, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

We introduce a novel algorithm for dynamic energy management (DEM) under performance constraints in chip multi-processors (CMPs). Using the novel concept of delayed instructions count, performance loss estimations are calculated at the end of each control period for each core. In addition, a Kalman filtering based approach is employed to predict workload in the next control period for which voltage-frequency pairs must be selected. This selection is done with a novel dynamic voltage and frequency scaling (DVFS) algorithm whose objective is to reduce energy consumption but without degrading performance beyond the user set threshold. Using our customized Sniper based CMP …

Optimization Of Patch Antennas Via Multithreaded Simulated Annealing Based Design Exploration, James Richie, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we present a new software framework for the optimization of the design of microstrip patch antennas. The proposed simulation and optimization framework implements a simulated annealing algorithm to perform design space exploration in order to identify the optimal patch antenna design. During each iteration of the optimization loop, we employ the popular MEEP simulation tool to evaluate explored design solutions. To speed up the design space exploration, the software framework is developed to run multiple MEEP simulations concurrently. This is achieved using multithreading to implement a manager-workers execution strategy. The number of worker threads is the same …

Modeling Dormant Fruit Trees For Agricultural Automation, Henry Medeiros, Donghun Kim, Jianxin Sun, Hariharan Seshadri, Shayan A. Akbar, Noha M. Elfiky, Johnny Park

Electrical and Computer Engineering Faculty Research and Publications

Dormant pruning of fruit trees is one of the most costly and labor‐intensive activities in specialty crop production. We present a system that solves the first step in the process of automated pruning: accurately measuring and modeling the fruit trees. Our system employs a laser sensor to collect observations of fruit trees from multiple perspectives, and it uses these observations to measure parameters needed for pruning. A split‐and‐merge clustering algorithm divides the collected data into three sets of points: trunk candidates, junction point candidates, and branches. The trunk candidates and junction point candidates are then further refined by a robust …

Event And Time-Triggered Control Module Layers For Individual Robot Control Architectures Of Unmanned Agricultural Ground Vehicles, Tyler Troyer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Automation in the agriculture sector has increased to an extent where the accompanying methods for unmanned field management are becoming more economically viable. This manifests in the industry’s recent presentation of conceptual cab-less machines that perform all field operations under the high-level task control of a single remote operator. A dramatic change in the overall workflow for field tasks that historically assumed the presence of a human in the immediate vicinity of the work is predicted. This shift in the entire approach to farm machinery work provides producers increased control and productivity over high-level tasks and less distraction from operating …

Development And Grasp Analysis Of A Sensorized Underactuated Finger, Mahyar Abdeetedal, Mehrdad Kermani Ph.D., P.Eng.

Electrical and Computer Engineering Publications

No abstract provided.

Grasp Evaluation Method For Applying Static Loads Leading To Beam Failure, Mahyar Abdeetedal, Mehrdad Kermani Ph.D., P.Eng.

Electrical and Computer Engineering Publications

This paper deals with the problem of purposefully failing or yielding an object by a robotic gripper. We propose a grasp quality measure fabricated for robotic harvesting in which picking a crop from its stem is desired. The proposed metric characterizes a suitable grasp configuration for systematically controlling the failure behavior of an object to break it at the desired location while avoiding damage on other areas. Our approach is based on failure task information and gripper wrench insertion capability. Failure task definition is accomplished using failure theories. Gripper wrench insertion capability is formulated by modeling the friction between the …

A Novel Real-Time Non-Invasive Hemoglobin Level Detection Using Video Images From Smartphone Camera, Golam Mushih Tanimul Ahsan, Md. O. Gani, Md Kamrul Hasan, Sheikh Iqbal Ahamed, William Chu, Mohammad Adibuzzaman, Joshua Field

Electrical and Computer Engineering Faculty Research and Publications

Hemoglobin level detection is necessary for evaluating health condition in the human. In the laboratory setting, it is detected by shining light through a small volume of blood and using a colorimetric electronic particle counting algorithm. This invasive process requires time, blood specimens, laboratory equipment, and facilities. There are also many studies on non-invasive hemoglobin level detection. Existing solutions are expensive and require buying additional devices. In this paper, we present a smartphone-based non-invasive hemoglobin detection method. It uses the video images collected from the fingertip of a person. We hypothesized that there is a significant relation between the fingertip …

Micro-Contacts Testing Using A Micro-Force Sensor Compatible With Biological Systems, Ronald A. Coutu Jr., Dushyant Tomer

Electrical and Computer Engineering Faculty Research and Publications

This paper presents the performance and reliability testing of microelectromechanical systems (MEMS) switches by using a micro-force sensor which was originally designed/used to conduct mechanical testing of biological cells. MEMS switches are key components for radio frequency (RF) applications due to their extremely low power consumption and small geometries over conventional technologies. However, unstable electrical contact resistance severely degrades the performance and reliability of such micro-switches. Therefore, our focus is to improve the performance and reliability of “cold” switched micro-contacts by using novel contact materials and engineered micro-contact surfaces. The contact metallurgies considered in this work are “similar” thin film …

Data Improving In Time Series Using Arx And Ann Models, Hermine Nathalie Akouemo Kengmo Kenfack, Richard J. Povinelli

Electrical and Computer Engineering Faculty Research and Publications

Anomalous data can negatively impact energy forecasting by causing model parameters to be incorrectly estimated. This paper presents two approaches for the detection and imputation of anomalies in time series data. Autoregressive with exogenous inputs (ARX) and artificial neural network (ANN) models are used to extract the characteristics of time series. Anomalies are detected by performing hypothesis testing on the extrema of the residuals, and the anomalous data points are imputed using the ARX and ANN models. Because the anomalies affect the model coefficients, the data cleaning process is performed iteratively. The models are re-learned on “cleaner” data after an …

Forensic State Acquisition From Internet Of Things (Fsaiot): A General Framework And Practical Approach For Iot Forensics Through Iot Device State Acquisition, Christopher S. Meffert, Devon R. Clark, Ibrahim Baggili, Frank Breitinger

Electrical & Computer Engineering and Computer Science Faculty Publications

IoT device forensics is a difficult problem given that manufactured IoT devices are not standardized, many store little to no historical data, and are always connected; making them extremely volatile. The goal of this paper was to address these challenges by presenting a primary account for a general framework and practical approach we term Forensic State Acquisition from Internet of Things (FSAIoT). We argue that by leveraging the acquisition of the state of IoT devices (e.g. if an IoT lock is open or locked), it becomes possible to paint a clear picture of events that have occurred. To this end, …

Breaking Into The Vault: Privacy, Security And Forensic Analysis Of Android Vault Applications, Xiaolu Zhang, Ibrahim Baggili, Frank Breitinger

Electrical & Computer Engineering and Computer Science Faculty Publications

In this work we share the first account for the forensic analysis, security and privacy of Android vault applications. Vaults are designed to be privacy enhancing as they allow users to hide personal data but may also be misused to hide incriminating files. Our work has already helped law enforcement in the state of Connecticut to reconstruct 66 incriminating images and 18 videos in a single criminal case. We present case studies and results from analyzing 18 Android vault applications (accounting for nearly 220 million downloads from the Google Play store) by reverse engineering them and examining the forensic artifacts …

Security For 5g Mobile Wireless Networks, Dongfeng Fang, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications

The advanced features of 5G mobile wireless network systems yield new security requirements and challenges. This paper presents a comprehensive survey on security of 5G wireless network systems compared to the traditional cellular networks. The paper starts with a review on 5G wireless networks particularities as well as on the new requirements and motivations of 5G wireless security. The potential attacks and security services with the consideration of new service requirements and new use cases in 5G wireless networks are then summarized. The recent development and the existing schemes for the 5G wireless security are presented based on the corresponding …

Observation And Understanding Of The Initial Unstable Electrical Contact Behaviors, Wanbin Ren, Nan Jiang, Cheng Chang, Shengjun Xue, Yu Chen, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Reliable and long-lifetime electrical contact is a very important issue in the field of radio frequency microelectromechanical systems (MEMS) and in energy transmission applications. In this paper, the initial unstable electrical contact phenomena under the conditions of micro-newton-scale contact force and nanometer-scale contact gap have been experimentally observed. The repetitive contact bounces at nanoscale are confirmed by the measured instantaneous waveforms of contact force and contact voltage. Moreover, the corresponding physical model for describing the competition between the electrostatic force and the restoring force of the mobile contact is present. Then, the dynamic process of contact closure is explicitly calculated …

On-Chip Detection Of Gel Transition Temperature Using A Novel Micro-Thermomechanical Method, Tsenguun Byambadorj, Erfan Dashtimoghadam, Mohamadali Malakoutian, Benyamin Davaji, Lobat Tayebi, James E. Richie, Chung-Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

We present a new thermomechanical method and a platform to measure the phase transition temperature at microscale. A thin film metal sensor on a membrane simultaneously measures both temperature and mechanical strain of the sample during heating and cooling cycles. This thermomechanical principle of operation is described in detail. Physical hydrogel samples are prepared as a disc-shaped gels (200 μm thick and 1 mm diameter) and placed between an on-chip heater and sensor devices. The sol-gel transition temperature of gelatin solution at various concentrations, used as a model physical hydrogel, shows less than 3% deviation from in-depth rheological results. …

On-Chip Training Of Memristor Crossbar Based Multi-Layer Neural Networks, Raqibul Hasan, Tarek M. Taha, Christopher Yakopcic

Electrical and Computer Engineering Faculty Publications

Memristor crossbar arrays carry out multiply-add operations in parallel in the analog domain, and so can enable neuromorphic systems with high throughput at low energy and area consumption. On-chip training of these systems have the significant advantage of being able to get around device variability and faults. This paper presents on-chip training circuits for multi-layer neural networks implemented using a single crossbar per layer and two memristors per synapse. Using two memristors per synapse provides double the synaptic weight precision when compared to a design that uses only one memristor per synapse. Proposed on-chip training system utilizes the back propagation …

Data Extraction From Web Tables: The Devil Is In The Details, George Nagy, Sharad C. Seth, Dongpu Jin, David W. Embley, Spencer Machado, Mukkai Krishnamoorthy

CSE Conference and Workshop Papers

We present a method based on header paths for efficient and complete extraction of labeled data from tables meant for humans. Although many table configurations yield to the proposed syntactic analysis, some require access to semantic knowledge. Clicking on one or two critical cells per table, through a simple interface, is sufficient to resolve most of these problem tables. Header paths, a purely syntactic representation of visual tables, can be transformed (“factored”) into existing representations of structured data such as category trees, relational tables, and RDF triples. From a random sample of 200 web tables from ten large statistical web …

End-To-End Conversion Of Html Tables For Populating A Relational Database, George Nagy, David W. Embley, Sharad C. Seth

CSE Conference and Workshop Papers

Automating the conversion of human-readable HTML tables into machine-readable relational tables will enable end-user query processing of the millions of data tables found on the web. Theoretically sound and experimentally successful methods for index-based segmentation, extraction of category hierarchies, and construction of a canonical table suitable for direct input to a relational database are demonstrated on 200 heterogeneous web tables. The methods are scalable: the program generates the 198 Access compatible CSV files in ~0.1s per table (two tables could not be indexed).

Application-Aware Cognitive Multi-Hop Wireless Networking Testbed And Experiments, Trenton T. Evans

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

In this thesis, we present a new architecture for application-aware cognitive multihop wireless networks (AC-MWN) with testbed implementations and experiments. Cognitive radio is a technique to adaptively use the spectrum so that the resource can be used more efficiently in a low cost way. Multihop wireless networks can be deployed quickly and flexibly without a fixed infrastructure. In presented new architecture, we study backbone routing schemes with network cognition, routing scheme with network coding and spectrum adaptation. A testbed is implemented to test the schemes for AC-MWN. In addition to basic measurements, we implement a video streaming application based on …

Multi-View Face Recognition From Single Rgbd Models Of The Faces, Donghun Kim, Bharath Comandur, Henry P. Medeiros, Noha M. Elfiky, Avinash Kak

Electrical and Computer Engineering Faculty Research and Publications

This work takes important steps towards solving the following problem of current interest: Assuming that each individual in a population can be modeled by a single frontal RGBD face image, is it possible to carry out face recognition for such a population using multiple 2D images captured from arbitrary viewpoints? Although the general problem as stated above is extremely challenging, it encompasses subproblems that can be addressed today. The subproblems addressed in this work relate to: (1) Generating a large set of viewpoint dependent face images from a single RGBD frontal image for each individual; (2) using hierarchical approaches based …