Browsing by Author "Zhang, Yibing"

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    EmoViz - Facial Expression Analysis & Emotion Data Visualization
    Barnett, Matthew; Evans, Thomas; Islam, Fuadul; Zhang, Yibing (Virginia Tech, 2018-05-02)
    The report describes the EmoViz project for the Multimedia, Hypertext, and Information Access Capstone at Virginia Tech during the Spring 2018 semester. The goal of the EmoViz project is to develop a tool that generates and displays visualizations made from Facial Action Coding System (FACS) emotion data. The client, Dr. Steven D. Sheetz, is a Professor of Accounting and Information Systems at Virginia Tech. Dr. Sheetz conducted a research project in 2009 to determine how human emotions are affected when a subject is confronted with analyzing a business audit. In the study, an actor was hired to record a five minute video of a simulated business audit in which they read a pre-written script containing specific visual cues at highlighted points throughout the duration of the audit. Participants of the study were divided into two groups, each of which was given a distinct set of accounting data to review prior to watching the simulation video. The first group received accounting data that had purposely been altered in a way that would indicate the actor was committing fraud by lying to the auditor. The second group received accounting data that correctly corresponded to the actor’s script so that it would appear there was no fraud committed. All participants watched the simulation video while their face movements were tracked using the Noldus FaceReader software to catalog emotional states. FaceReader samples data points on the face every 33 milliseconds and uses a proprietary algorithm to quantify the following emotions at each sampling: neutral, happy, sad, angry, surprise, and disgust. After cataloging roughly 9,000 data rows per participant, Dr. Sheetz adjusted the data and exported each set into .csv files. From there, the EmoViz team uploaded these files into the newly developed system where the data was then processed using Apache Spark. Using Spark’s virtual cluster computing, the .csv data was transformed into DataFrames which helps to map each emotion to a named column. These named columns were then queried in order to generate visualizations and display certain emotions over time. Additionally, the queries helped to compare and contrast different data sets so the client could analyze the visualizations. After the analysis, the client could draw conclusions about how human emotions are affected when confronted with a business audit.
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    Novel Optical Sensors for High Temperature Measurement in Harsh Environments
    Zhang, Yibing (Virginia Tech, 2003-07-24)
    Accurate measurement of temperature is essential for the safe and efficient operation and control of a vast range of industrial processes. Many of these processes involve harsh environments, such as high temperature, high pressure, chemical corrosion, toxicity, strong electromagnetic interference, and high-energy radiation exposure. These extreme physical conditions often prevent conventional temperature sensors from being used or make them difficult to use. Novel sensor systems should not only provide accurate and reliable temperature measurements, but also survive the harsh environments through proper fabrication material selections and mechanical structure designs. This dissertation presents detailed research work on the design, modeling, implementation, analysis, and performance evaluation of novel optical high temperature sensors suitable for harsh environment applications. For the first time to our knowledge, an optical temperature sensor based on the broadband polarimetric differential interferometric (BPDI) technology is proposed and tested using single crystal sapphire material. With a simple mechanically structured sensing probe, in conjunction with an optical spectrum-coded interferometric signal processing technique, the proposed single crystal sapphire optical sensor can measure high temperature up to 1600 oC in the harsh environments with high accuracy, corrosion resistance, and long-term measurement stability. Based on the successfully demonstrated sensor prototype in the laboratory, we are confident of the next research step on sensor optimization and scale-up for full field implementations. The goal for this research has been to bring this temperature sensor to a level where it will become commercially viable for harsh environment applications associated with industries.
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    Observation Of The Enhanced Backscattering Of Light By The End Of A Tilted Dielectric Cylinder Owing To The Caustic Merging Transition
    Marston, Philip L.; Zhang, Yibing; Thiessen, David B. (Optical Society of America, 2003-03-01)
    The scattering of light by obliquely illuminated circular dielectric cylinders was previously demonstrated to be enhanced by a merger of Airy caustics at a critical tilt angle. [Appl. Opt. 37, 1534 (1998)]. A related enhancement is demonstrated here for backward and near-backward scattering for cylinders cut with a flat end perpendicular to the cylinder's axis. It is expected that merged caustics will enhance the backscattering by clouds of randomly oriented circular cylinders that have appropriately flat ends. (C) 2003 Optical Society of America.