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Full-Text Articles in Computer Engineering

Role Of Diffusive, Photovoltaic, And Thermal Effects In Beam Fanning In Linbo3, Jaw-Jueh Liu, Partha P. Banerjee, Q. W. Song Apr 2016

Role Of Diffusive, Photovoltaic, And Thermal Effects In Beam Fanning In Linbo3, Jaw-Jueh Liu, Partha P. Banerjee, Q. W. Song

Partha Banerjee

We analyze the steady-state (Gaussian) beam fanning in LiNbO3 from the nonlinearly coupled Kukhtarev equations by including both diffusive and photovoltaic effects and by adding the thermal effect in the calculation. There is good agreement between theory and experiment. The results show a symmetric beam-fanning pattern whose size depends on the beam waist and the power. Possible applications of our results in nondestructive testing of material parameters and optical limiting are discussed.


Simulation Of Two-Dimensional Nonlinear Envelope Pulse Dynamics By A Two-Step Spatiotemporal Angular Spectrum Method, H. K. Sim, Adrianus Korpel, Karl E. Lonngren, Partha P. Banerjee Apr 2016

Simulation Of Two-Dimensional Nonlinear Envelope Pulse Dynamics By A Two-Step Spatiotemporal Angular Spectrum Method, H. K. Sim, Adrianus Korpel, Karl E. Lonngren, Partha P. Banerjee

Partha Banerjee

We present an extension of our previous nonlinear beam-simulation method to the propagation and interaction of pulse envelopes. The extra time dimension is applied in the context of a dispersive nonlinear medium that is described by a Klein–Gordon equation with an added cubically nonlinear, self-focusing term. Pulse propagation in this medium is modeled as the evolution of a spatiotemporal spectrum—i.e., the frequency-dependent angular spectrum of the pulse envelope—traversing a sequence of self-induced, thin, weak phase filters. Preliminary simulation experiments show agreement with known behavior in the absence of nonlinearity, confirm the existence of an (apparently unstable ...


Theoretical And Experimental Studies Of Propagation Of Beams Through A Finite Sample Of A Cubically Nonlinear Material, Partha P. Banerjee, Raj M. Misra, M. Maghraoui Apr 2016

Theoretical And Experimental Studies Of Propagation Of Beams Through A Finite Sample Of A Cubically Nonlinear Material, Partha P. Banerjee, Raj M. Misra, M. Maghraoui

Partha Banerjee

Propagation of an externally focused or defocused Gaussian beam in a cubically nonlinear material is studied analytically and experimentally. The theoretical analysis is applied to determine the sign and magnitude of n2 for a material by means of a single-beam experiment with a finite nonlinear sample within which propagational diffraction cannot be neglected. Experimental results for a solution of chlorophyll in ethanol are reported. Based on available theory, an average n2 can be defined for a nonlinearity of thermal origin, and this value is found to be in good agreement with experimental results. Finally, the theoretical analysis and ...


On A Simple Derivation Of The Fresnel Diffraction Formula And A Transfer Function Approach To Wave Propagation, Partha P. Banerjee, Ting-Chung Poon Apr 2016

On A Simple Derivation Of The Fresnel Diffraction Formula And A Transfer Function Approach To Wave Propagation, Partha P. Banerjee, Ting-Chung Poon

Partha Banerjee

The Fresnel diffraction formula is straightforwardly obtained by solving a partial differential equation (PDE) for envelope propagation using Fourier transform techniques. The PDE, in turn, can be derived from the dispersion relation of a linear medium by employing a simple operator formalism. The transfer function and impulse response of propagation follows as a spin‐off and is used to solve illustrative problems. Huygens’ principle is visualized as a consequence of the convolution property of linear systems.


Notch Spatial Filtering With An Acousto-Optic Modulator, Partha P. Banerjee, Dongqing Cao, Ting-Chung Poon Apr 2016

Notch Spatial Filtering With An Acousto-Optic Modulator, Partha P. Banerjee, Dongqing Cao, Ting-Chung Poon

Partha Banerjee

The role of acousto-optic (AO) modulators in programmable real-time image processing has recently been demonstrated. For fully investigating the image-processing capabilities of the AO modulator, general techniques to derive spatial transfer functions are needed for a variety of physical situations. We develop a technique to determine the spatial transfer functions numerically for various cases of beam incidence on an AO modulator. Normal incidence and incidence at twice the Bragg angle are investigated as examples for which double-sided and single-sided notch spatial filtering, respectively, are achieved. The observed spatial-filtering characteristics are reconciled with simple intuitive physical arguments.


Nonlinear Transverse Effects In Second-Harmonic Generation, Pawel Pliszka, Partha P. Banerjee Apr 2016

Nonlinear Transverse Effects In Second-Harmonic Generation, Pawel Pliszka, Partha P. Banerjee

Partha Banerjee

We study a three-dimensional model of interaction of fundamental-frequency and second-harmonic beams in a quadratically nonlinear medium. Numerical simulations of the three-dimensional propagation problem in the presence of diffraction and anisotropy are performed under the paraxial approximation. The role of the transverse effects in various regimes is investigated. We demonstrate the effect of phase modulation and an induced nonlinear focusing during the interaction of the fundamental frequency with the generated second harmonic.


Multiwave Coupling In A High-Gain Photorefractive Polymer, Kenji Matsushita, Partha P. Banerjee, S. Ozaki, Daisuke Miyazaki Apr 2016

Multiwave Coupling In A High-Gain Photorefractive Polymer, Kenji Matsushita, Partha P. Banerjee, S. Ozaki, Daisuke Miyazaki

Partha Banerjee

The characteristics of a new high-gain photorefractive polymer composite with a PNP chromophore are investigated. Competition between beam fanning and two-wave coupling (TWC) is predicted and verified experimentally. The intensity dependence of TWC gain is studied. Higher diffraction order and forward phase conjugation in a TWC geometry are observed and explained.


Linear And Nonlinear Propagation In Negative Index Materials, Partha P. Banerjee, George Nehmetallah Apr 2016

Linear And Nonlinear Propagation In Negative Index Materials, Partha P. Banerjee, George Nehmetallah

Partha Banerjee

We analyze linear propagation in negative index materials by starting from a dispersion relation and by deriving the underlying partial differential equation. Transfer functions for propagation are derived in temporal and spatial frequency domains for unidirectional baseband and modulated pulse propagation, as well as for beam propagation. Gaussian beam propagation is analyzed and reconciled with the ray transfer matrix approach as applied to propagation in negative index materials. Nonlinear extensions of the linear partial differential equation are made by incorporating quadratic and cubic terms, and baseband and envelope solitary wave solutions are determined. The conditions for envelope solitary wave solutions ...


Application Of Up-Sampling And Resolution Scaling To Fresnel Reconstruction Of Digital Holograms, Logan Williams, George Nehmetallah, Rola Aylo, Partha P. Banerjee Apr 2016

Application Of Up-Sampling And Resolution Scaling To Fresnel Reconstruction Of Digital Holograms, Logan Williams, George Nehmetallah, Rola Aylo, Partha P. Banerjee

Partha Banerjee

Fresnel transform implementation methods using numerical preprocessing techniques are investigated in this paper. First, it is shown that up-sampling dramatically reduces the minimum reconstruction distance requirements and allows maximal signal recovery by eliminating aliasing artifacts which typically occur at distances much less than the Rayleigh range of the object. Second, zero-padding is employed to arbitrarily scale numerical resolution for the purpose of resolution matching multiple holograms, where each hologram is recorded using dissimilar geometric or illumination parameters. Such preprocessing yields numerical resolution scaling at any distance. Both techniques are extensively illustrated using experimental results.


Achieving Enhanced Gain In Photorefractive Polymers By Eliminating Electron Contributions Using Large Bias Fields, C. M. Liebig, S. H. Buller, Partha P. Banerjee, S. A. Basun, Pierre-Alexandre Blanche, J. Thomas, Cory W. Christenson, N. Peyghambarian, Dean R. Evans Apr 2016

Achieving Enhanced Gain In Photorefractive Polymers By Eliminating Electron Contributions Using Large Bias Fields, C. M. Liebig, S. H. Buller, Partha P. Banerjee, S. A. Basun, Pierre-Alexandre Blanche, J. Thomas, Cory W. Christenson, N. Peyghambarian, Dean R. Evans

Partha Banerjee

Photorefractive polymers have been extensively studied for over two decades and have found applications in holographic displays and optical image processing. The complexity of these materials arises from multiple charge contributions, for example, leading to the formation of competing photorefractive gratings. It has been recently shown that in a photorefractive polymer at relatively moderate applied electric fields the primary charge carriers (holes) establish an initial grating, followed by a subsequent competing grating (electrons) resulting in a decreased two-beam coupling and diffraction efficiencies. In this paper, it is shown that with relatively large sustainable bias fields, the two-beam coupling efficiency is ...


3d Visualization Using Pulsed And Cw Digital Holographic Tomography Techniques, George Nehmetallah, Partha P. Banerjee, D. Ferree, R. Kephart, Sarat C. Praharaj Apr 2016

3d Visualization Using Pulsed And Cw Digital Holographic Tomography Techniques, George Nehmetallah, Partha P. Banerjee, D. Ferree, R. Kephart, Sarat C. Praharaj

Partha Banerjee

We outline the use of digital holographic tomography to determine the three-dimensional (3D) shapes of falling and static objects, such as lenslets and water droplets. Reconstruction of digitally recorded inline holograms is performed using multiplicative and Radon transform techniques to reveal the exact 3D shapes of the objects.


An Ontology And Integration Framework For Smart Communities, Steven Ray, Shishir Kinkar, Mark Hennessy Jan 2016

An Ontology And Integration Framework For Smart Communities, Steven Ray, Shishir Kinkar, Mark Hennessy

Steven R Ray

This paper describes our work concerning the definition of a neutral, abstract ontology, and framework that supports the vision and diverse contexts of a smart community. This framework is composed of a general, core ontology that supports what many are calling the Internet of Things (IoT), a scalable number of extension ontologies to describe various application perspectives, and a mapping methodology to relate external data and/or schemas to our ontology. Finally, we show why this ontology is scalable and generic enough to support a wide range of smart devices, systems, and people.


Dynamic Modeling, Parameter Estimation And Control Of A Leg Prosthesis Test Robot, Hanz Richter, Daniel Simon, William Smith, Sergey Samorezov Dec 2015

Dynamic Modeling, Parameter Estimation And Control Of A Leg Prosthesis Test Robot, Hanz Richter, Daniel Simon, William Smith, Sergey Samorezov

Hanz Richter

Robotic testing can facilitate the development of new concepts, designs and control systems for prosthetic limbs. Human subject test clearances, safety and the lack of repeatability associated with human trials can be reduced or eliminated with automated testing, and test modalities are possible which are dangerous or inconvenient to attempt with patients. This paper describes the development, modeling, parameter estimation and control of a robot capable of reproducing two degree-of-freedom hip motion in the sagittal plane. Hip vertical displacement and thigh angle motion profiles are applied to a transfemoral prosthesis attached to the robot. A treadmill is used as walking ...


Can Declared Strategy Voting Be An Effective Instrument For Group Decision-Making?, Lorrie Cranor Dec 2015

Can Declared Strategy Voting Be An Effective Instrument For Group Decision-Making?, Lorrie Cranor

Lorrie F Cranor

The goal of this research is to determine whether declared strategy voting can be an effective tool for group decision-making. Declared strategy voting is a novel group decision-making procedure in which preference is specified using voting strategies - first-order mathematical functions that specify a choice in terms of zero or more parameters. This research will focus on refining the declared strategy voting concept, developing an accessible implementation of declared strategy voting that can be used for mock elections, assessing the potential impacts of declared strategy voting, and evaluating the effectiveness of declared strategy voting for group decision-making. This proposal describes the ...


Design And Implementation Of A Practical Security-Conscious Electronic Polling System, Lorrie Cranor, Ron Cytron Dec 2015

Design And Implementation Of A Practical Security-Conscious Electronic Polling System, Lorrie Cranor, Ron Cytron

Lorrie F Cranor

We present the design and implementation of Sensus, a practical, secure and private system for conducting surveys and elections over computer networks. Expanding on the work of Fujioka, Okamoto, and Ohta, Sensus uses blind signatures to ensure that only registered voters can vote and that each registered voter only votes once, while at the same time maintaining voters' privacy. Sensus allows voters to verify independently that their votes were counted correctly, and anonymously challenge the results should their votes be miscounted. We outline seven desirable properties of voting systems and show that Sensus satisfied these properties well, in some cases ...


Answer Credibility: A Language Modeling Approach To Answer Validation, Protima Banerjee, Hyoil Han Sep 2015

Answer Credibility: A Language Modeling Approach To Answer Validation, Protima Banerjee, Hyoil Han

Hyoil Han

Answer Validation is a topic of significant interest within the Question Answering community. In this paper, we propose the use of language modeling methodologies for Answer Validation, using corpus-based methods that do not require the use of external sources. Specifically, we propose a model for Answer Credibility which quantifies the reliability of a source document that contains a candidate answer and the Question’s Context Model.


Survey Of Word Sense Disambiguation Approaches, Xiaohua Zhou, Hyoil Han Sep 2015

Survey Of Word Sense Disambiguation Approaches, Xiaohua Zhou, Hyoil Han

Hyoil Han

Word Sense Disambiguation (WSD) is an important but challenging technique in the area of natural language processing (NLP). Hundreds of WSD algorithms and systems are available, but less work has been done in regard to choosing the optimal WSD algorithms. This paper summarizes the various knowledge sources used for WSD and classifies existing WSD algorithms according to their techniques. The rationale, tasks, performance, knowledge sources used, computational complexity, assumptions, and suitable applications for each class of WSD algorithms are also discussed. This paper will provide users with general knowledge for choosing WSD algorithms for their specific applications or for further ...


Dense And Switched Modular Primitives For Bond Graph Model Design, K. Seo, Z. Fan, Jianjun Hu, E. Goodman, R. Rosenberg Jun 2015

Dense And Switched Modular Primitives For Bond Graph Model Design, K. Seo, Z. Fan, Jianjun Hu, E. Goodman, R. Rosenberg

Jianjun Hu

No abstract provided.


Automated Synthesis Of Mechanical Vibration Absorbers Using Genetic Programming, Jianjun Hu, E. Goodman, S. Li, R. Rosenberg Jun 2015

Automated Synthesis Of Mechanical Vibration Absorbers Using Genetic Programming, Jianjun Hu, E. Goodman, S. Li, R. Rosenberg

Jianjun Hu

No abstract provided.


System-Level Synthesis Of Mems Via Genetic Programming And Bond Graphs, Z. Fan, K. Seo, Jianjun Hu, R. Rosenberg, E. Goodman Jun 2015

System-Level Synthesis Of Mems Via Genetic Programming And Bond Graphs, Z. Fan, K. Seo, Jianjun Hu, R. Rosenberg, E. Goodman

Jianjun Hu

No abstract provided.


Towards Synthesis Of Platform-Aware Attack-Resilient Control Systems: Extended Abstract, Miroslav Pajic, Nicola Bezzo, James Weimer, Rajeev Alur, Rahul Mangharam, Nathan Michael, George Pappas, Oleg Sokolsky, Paulo Tabuada, Stephanie Weirich, Insup Lee Jun 2015

Towards Synthesis Of Platform-Aware Attack-Resilient Control Systems: Extended Abstract, Miroslav Pajic, Nicola Bezzo, James Weimer, Rajeev Alur, Rahul Mangharam, Nathan Michael, George Pappas, Oleg Sokolsky, Paulo Tabuada, Stephanie Weirich, Insup Lee

Stephanie Weirich

No abstract provided.


Parallel Computation In Communication And Signal Processing, Amean Al_Safi, Bradley Bazuin, Liqaa Alhafadhi May 2015

Parallel Computation In Communication And Signal Processing, Amean Al_Safi, Bradley Bazuin, Liqaa Alhafadhi

Amean S Al_Safi

The powerful computation of GPU has increased the computation speed up of many systems. This paper summarize some of the most important work in the field of communication and signal processing using GPU


Performance Analysis Of A New Computer Aided Detection System For Identifying Lung Nodules On Chest Radiographs, Russell Hardie, Steven Rogers, Terry Wilson, Adam Rogers May 2015

Performance Analysis Of A New Computer Aided Detection System For Identifying Lung Nodules On Chest Radiographs, Russell Hardie, Steven Rogers, Terry Wilson, Adam Rogers

Russell C. Hardie

A new computer aided detection (CAD) system is presented for the detection of pulmonary nodules on chest radiographs. Here, we present the details of the proposed algorithm and provide a performance analysis using a publicly available database to serve as a benchmark for future research efforts. All aspects of algorithm training were done using an independent dataset containing 167 chest radiographs with a total of 181 lung nodules. The publicly available test set was created by the Standard Digital Image Database Project Team of the Scientific Committee of the Japanese Society of Radiological Technology (JRST). The JRST dataset used here ...


A Collaborative Adaptive Wiener Filter For Multi-Frame Super-Resolution, Khaled Mohamed, Russell Hardie May 2015

A Collaborative Adaptive Wiener Filter For Multi-Frame Super-Resolution, Khaled Mohamed, Russell Hardie

Russell C. Hardie

Factors that can limit the effective resolution of an imaging system may include aliasing from under-sampling, blur from the optics and external factors, and sensor noise. Image restoration and super-resolution (SR) techniques can be used to improve image resolution. One SR method, developed recently, is the adaptive Wiener filter (AWF) SR algorithm. This is a multi-frame SR method that combines registered temporal frames through a joint nonuniform interpolation and restoration process to provide a high-resolution image estimate. Variations of this method have been demonstrated to be effective for multi-frame SR, as well demosaicing RGB and polarimetric imagery. While the AWF ...


New Model Of Productive Online Discussion And Its Implications For Research And Instruction, Fei Gao, Charles Wang, Yanling Sun May 2015

New Model Of Productive Online Discussion And Its Implications For Research And Instruction, Fei Gao, Charles Wang, Yanling Sun

Fei Gao

We develop a new model of productive online discussion based on a brief review of research literature on online discussion. As compared to previous discussion models, the new model provides a more systematic and comprehensive framework to understand how learning occurs through online discussion. Based on the new model, we propose several directions for research on improving the quality of online discussion and learning.


Student Engagement In Distance Learning Environments: A Comparison Of Threaded Discussion Forums And Text-Focused Wikis, Fei Gao, David Wong May 2015

Student Engagement In Distance Learning Environments: A Comparison Of Threaded Discussion Forums And Text-Focused Wikis, Fei Gao, David Wong

Fei Gao

The purpose of this study was to improve the quality of students’ online discussion of assigned readings in an online course. To improve the focus, depth, and connectedness of online discussion, the first author designed a text–focused Wiki that simultaneously displayed the assigned reading and students’ comments side by side in adjacent columns. In the text–focused Wiki, students were able to read the assigned text in the left column and type their comments or questions in the right column adjacent to the sentence or passage that sparked their interest. In post–participation surveys, data were gathered about students ...


Direction Of Slip Detection For A Biomimetic Tactile Sensor, Erik Engeberg, Morteza Vatani, Jae-Won Choi Apr 2015

Direction Of Slip Detection For A Biomimetic Tactile Sensor, Erik Engeberg, Morteza Vatani, Jae-Won Choi

Dr. Jae-Won Choi

A biomimetic tactile sensor (BTS) is developed from strips of electrically conductive carbon nanotubes (CNTs) mixed in a polymer matrix that is embedded within a flexible polyurethane shell. The mechanical compliance of the BTS is similar to the human fingertip. Experiments are performed which show that the BTS can be used to detect slip and the direction that slip occurs by examining the relative timing among force signals from adjacent strips of CNTs and the frequency content of the force signals. The BTS can also detect forces applied at distinct points on the surface of the BTS.


Diversified Users' Satisfaction With Advanced Mobile Phone Features, Chen Ling, Wonil Hwang, Gavriel Salvendy Apr 2015

Diversified Users' Satisfaction With Advanced Mobile Phone Features, Chen Ling, Wonil Hwang, Gavriel Salvendy

Dr. Chen Ling

Mobile phones are widely used all over the world, and with their increasing number of value-added features, they are becoming far more than a mere mobile voice communication device. Rather, they provide a powerful platform for accessing information universally. This paper reports a study which scrutinized users’ preference levels with five new mobile phone design features facilitating universal information access through mobile phones: camera, colour screen, voice-activated dialing, Internet browsing, and wireless connectivity (e.g. Bluetooth, infrared, etc.). The survey study involved college students and investigated the degree to which each of the above features impacts the users’ overall satisfaction ...


Validating Information Complexity Questionnaires Using Travel Web Sites, Chen Ling, Miguel Lopez, Jing Xing Apr 2015

Validating Information Complexity Questionnaires Using Travel Web Sites, Chen Ling, Miguel Lopez, Jing Xing

Dr. Chen Ling

With the prevalent use of visual interfaces and the increasing demand to display more information, information complexity becomes a major concern for designers. Complex interfaces affect the system effectiveness, efficiency, and even safety. Researchers at the Federal Aviation Administration have developed two sets of psychometric questionnaires to evaluate information complexity of air traffic control displays. This study adapted the questionnaires for commercial visual interfaces and validated them with directed and exploratory tasks on three travel websites. The results confirmed that both complexity questionnaires have satisfactory reliability, validity, and sensitivity. But questionnaire B demonstrated higher sensitivity than Questionnaire A.


A Comparison Between Single And Dual Monitor Productivity And The Effects Of Window Management Styles On Performance, Alex Stegman, Chen Ling, Randa Shehab Apr 2015

A Comparison Between Single And Dual Monitor Productivity And The Effects Of Window Management Styles On Performance, Alex Stegman, Chen Ling, Randa Shehab

Dr. Chen Ling

Several research studies have been published on user opinion and productivity of using dual monitor systems. These studies found that users typically enjoy using multiple monitors, but none found a strong increase in performance and productivity. Other researchers have focused on improving multiple monitor usability, but often without any statistical framework. This study compared single and dual monitor productivity measures: task time, cursor movement, and number of window switches. Additionally, window management styles (WMS) were studied in order to help designers understand user behavior better. WMS were broken into two categories, toggler and resizer, and then compared to the WMS ...