Computer Engineering Commons^™

Examination Of Chaotic Signal Encryption And Recovery For Secure Communication Using Hybrid Acousto-Optic Feedback, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

Generation of chaos from acousto-optic (A-O)Bragg cell modulators with an electronic feedback has been studied for over 3 decades. Since an acousto-optic Bragg cell with zeroth- and first-order feedback exhibits chaotic behavior past the threshold for bistability, such a system was recently examined for possible chaotic encryption of simple messages (such as a low-amplitude sinusoidal signal) applied via the bias input of the sound cell driver. Subsequent recovery of the message signal was carried out via a heterodyne-type strategy employing a locally generated chaotic carrier, with threshold parameters matched to the transmitting Bragg cell.

In this paper, we present numerical …

Quasi-Orthogonal Space-Time Block Coding Using Polynomial Phase Modulation, Omar Granados, Jean Andrian

Electrical and Computer Engineering Faculty Publications

Recently, polynomial phase modulation (PPM) was shown to be a power- and bandwidth-efficient modulation format. These two characteristics are in high demand nowadays specially in mobile applications, where devices with size, weight, and power (SWaP) constraints are common. In this paper, we propose implementing a full-diversity quasiorthogonal space-time block code (QOSTBC) using polynomial phase signals as modulation format. QOSTBCs along with PPM are used in order to improve the power efficiency of communication systems with four transmit antennas. We obtain the optimal PPM constellations that ensure full diversity and maximize the QOSTBC's minimum coding gain distance. Simulation results show that …

Behavior-Based Mobility Prediction For Seamless Handoffs In Mobile Wireless Networks, Weetit Wanalertlak, Ben Lee, Chansu Yu, Myungchul Kim, Seung-Min Park, Won-Tae Kim

Electrical and Computer Engineering Faculty Publications

The field of wireless networking has received unprecedented attention from the research community during the last decade due to its great potential to create new horizons for communicating beyond the Internet. Wireless LANs (WLANs) based on the IEEE 802.11 standard have become prevalent in public as well as residential areas, and their importance as an enabling technology will continue to grow for future pervasive computing applications. However, as their scale and complexity continue to grow, reducing handoff latency is particularly important. This paper presents the Behavior-based Mobility Prediction scheme to eliminate the scanning overhead incurred in IEEE 802.11 networks. This …

Scalar Em Beam Propagation In Inhomogeneous Media, John M. Jarem, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

In the previous chapter, we reviewed some of the mathematical preliminaries that will be useful later on in the text. In this chapter, we discuss some of the basic concepts of scalar wave propagation, and discuss an important numerical method, called the beam propagation method (BPM), to study propagation in linear media and in media with induced nonlinearities. Furthermore, we also discuss propagation through induced gratings, both transmission and reflection type, in order to assess energy coupling between participating waves. Finally, we introduce readers to an important characterization method, called the z-scan method, which is often used to determine the …

Binary And Core-Shell Nanoparticle Dispersed Liquid Crystal Cells For Metamaterial Applications, George Nehmetallah, Rola Aylo, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We theoretically explored the feasibility of a tunable metamaterial using binary as well as core-shell nanoparticle dispersed liquid crystal cells in the infrared and optical regimes. Owing to the spatial variation of the permittivity of the liquid crystal host upon the application of a bias voltage, the host was decomposed into a layered medium and the effective refractive index recalculated for each layer due to the distribution of polaritonic and plasmonic nanoparticles.

The scattering, extinction, and absorption of such a nanoparticle dispersed liquid crystal cell were also found. Depending on the applied voltage bias across the liquid crystal host, the …

Anisotropic Electrical Properties Of Nanostructured Metallic Thin Films, Mo Ahoujja, Piyush Shah, Andrew Saragan, Said Elhamri, Elena A. Guliants

Electrical and Computer Engineering Faculty Publications

High surface area, porous, metallic (Ti, Cr) nanorod thin ¯lms with columnar microstructure can be deposited using conventional physical vapor deposition technique of E-beam evaporation. The technique relies on the physical vapor deposition onto a static substrate oriented in a position where °ux from the source material (Ti, Cr) arrives at oblique angle. The adatoms provides geometrical shadowing which results in growth of nanorod columns in the direction of vapor source. Deposition conditions such as angle of the incoming vapor °ux, substrate temperature, surface di®usion etc. have strong in°uence on the shape and arrangement of the columnar thin ¯lms. In …

A Cooperative Diversity-Based Robust Mac Protocol In Wireless Ad Hoc Networks, Sangman Moh, Chansu Yu

Electrical and Computer Engineering Faculty Publications

In interference-rich and noisy environment, wireless communication is often hampered by unreliable communication links. Recently, there has been active research on cooperative communication that improves the communication reliability by having a collection of radio terminals transmit signals in a cooperative way. This paper proposes a medium access control (MAC) algorithm, called Cooperative Diversity MAC (CD-MAC), which exploits the cooperative communication capability of the physical (PHY) layer to improve robustness in wireless ad hoc networks. In CD-MAC, each terminal proactively selects a partner for cooperation and lets it transmit simultaneously so that this mitigates interference from nearby terminals, and thus, improves …

Single-Beam Holographic Tomography Creates Images In Three Dimensions, George Nehmetallah, Partha P. Banerjee, Nickolai Kukhtarev

Electrical and Computer Engineering Faculty Publications

In digital holography (DH), the interference between light scattered from an object and a reference wave is recorded using a CCD camera. DH has various advantages over analog holography: no film processing is needed, reconstruction is performed using numerical methods, and no further experimental setup is necessary. However, one of the disadvantages of DH is that current CCDs have a resolution of approximately 1,000 lines/mm, which is less than that of photographic film.

On Reducing Communication Energy Using Cross-Sensor Coding Technique, Kien Nguyen, Thinh Nguyen, Sen-Ching Cheung

Electrical and Computer Engineering Faculty Publications

This paper addresses the uneven communication energy problem in data gathering sensor networks where the nodes closer to the sink tend to consume more energy than those of the farther nodes. Consequently, the lifetime of a network is significantly shortened. We propose a cross-sensor coding technique using On-Off keying which exploits (a) the tradeoff between delay and energy consumption and (b) the network topology in order to alleviate the problem of unequal energy consumption. We formulate our coding problem as an integer linear programming problem and show how to construct a number of codes based on different criteria. We show …

Fluorinated Templates For Energy-Related Nanomaterials And Applications, Mohammed J. Meziani, Fushen Lu, Li Cao, Christopher E. Bunker, Elena A. Guliants, Ya-Ping Sun

Electrical and Computer Engineering Faculty Publications

Fluorinated ionomer membranes, as represented by the commercially available Nafion films, are macroscopically homogeneous and optically transparent but microscopically inhomogeneous with the presence of nanoscale hydrophilic cavities. These cavities serve as nanoscale reactors for the synthesis of nanoparticles from a variety of materials. The membranes with embedded nanoscale semiconductors, still optically transparent, have been used as sheet-photocatalysts for energy conversion applications, while those with embedded reactive metals used as nano-energetic materials for hydrogen generation and beyond. This chapter provides an overview on the templated synthesis of nanomaterials in fluorinated ionomer membranes and the various energy-related applications of this unique class …

Comparison Of Turbulence-Induced Scintillations For Multi-Wavelength Laser Beacons Over Tactical (7 Km) And Long (149 Km) Atmospheric Propagation Paths, Mikhail Vorontsov, Venkata S. Rao Gudimetla, Gary W. Carhart, Thomas Weyrauch, Svetlana Lachinova, Ernst Polnau, Joseph Rierson, Leonid A. Beresnev, Jony Jiang Liu, Jim F. Riker

Electrical and Computer Engineering Faculty Publications

We report results of the experimental analysis of atmospheric effects on laser beam propagation over two distinctive propagation paths: a long-range (149 km) propagation path between Mauna Loa (Island of Hawaii) and Haleakala (Island of Maui) mountains, and a tactical-range (7 km) propagation path between the roof of the Dayton Veterans Administration Medical Center (VAMC) and the Intelligent Optics Laboratory (IOL/UD) located on the 5th floor of the University of Dayton College Park Center building. Both testbeds include three laser beacons operating at wavelengths 532 nm, 1064 nm, and 1550 nm and a set of identical optical receiver systems with …

Multi-Pose Face Recognition And Tracking System, Binu Muraleedharan Nair, Jacob Foytik, Richard Tompkins, Yakov Diskin, Theus Aspiras, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

We propose a real time system for person detection, recognition and tracking using frontal and profile faces. The system integrates face detection, face recognition and tracking techniques. The face detection algorithm uses both frontal face and profile face detectors by extracting the 'Haar' features and uses them in a cascade of boosted classifiers. The pose is determined from the face detection algorithm which uses a combination of profile and frontal face cascades and, depending on the pose, the face is compared with a particular set of faces having the same range for classification. The detected faces are recognized by projecting …

Performance Measures In Acousto-Optic Chaotic Signal Encryption System Subject To Parametric Variations And Additive Noise, Monish Ranjan Chatterjee, Anjan K. Ghosh, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

Signal encryption and recovery using chaotic optical waves has been a subject of active research in the past 10 years. Since an acousto-optic Bragg cell with zeroth- and first-order feedback exhibits chaotic behavior past the threshold for bistability, such a system was recently examined for possible chaotic encryption using a low-amplitude sinusoidal signal applied via the bias input of the sound cell driver.

Subsequent recovery of the message signal was carried out via a heterodyne strategy employing a locally generated chaotic carrier, with threshold parameters matched to the transmitting Bragg cell. The simulation results, though encouraging, were limited to relatively …

Consideration Of Dispersion And Group Velocity Dispersion In The Determination Of Velocities Of Electromagnetic Propagation, Monish Ranjan Chatterjee, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Electromagnetic (EM) propagation velocities play an important role in the determination of power and energy flow in materials and interfaces. It is well known that group and phase velocities need to be in opposition in order to achieve negative refractive index.

Recently, we have shown that considerable differences may exist in phase, group and signal/energy velocities for normal and anomalous dispersion, especially near dielectric resonances. This paper examines the phase and group velocities in the presence of normal and anomalous dispersion, and group velocity dispersion (GVD), which requires introduction of the second order coefficient in the permittivity and permeability models.

Harvesting Single Ferroelectric Domain Stressed Nanoparticles For Optical And Ferroic Applications, Gary Cook, J. L. Barnes, S. A. Basun, Dean R. Evans, Ron F. Ziolo, Arturo Ponce, Victor Yu. Reshetnyak, Anatoliy Glushchenko, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We describe techniques to selectively harvest single ferroelectric domain nanoparticles of BaTiO3 as small as 9 nm from a plethora of nanoparticles produced by mechanical grinding. High resolution transmission electron microscopy imaging shows the unidomain atomic structure of the nanoparticles and reveals compressive and tensile surface strains which are attributed to the preservation of ferroelectric behavior in these particles.

We demonstrate the positive benefits of using harvested nanoparticles in disparate liquid crystal systems.

Characterization Of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons, Mikhail Vorontsov, Gary W. Carhart, Venkata S. Rao Gudimetla, Thomas Weyrauch, Eric Stevenson, Svetlana Lachinova, Leonid A. Beresnev, Jony Jiang Liu, Karl Rehder, Jim F. Riker

Electrical and Computer Engineering Faculty Publications

We describe preliminary results of a set of laser beam propagation experiments performed over a long (149 km) near-horizontal propagation path between Mauna Loa (Hawaii Island) and Haleakala (Island of Maui) mountains in February 2010. The distinctive feature of the experimental campaign referred to here as the Coherent Multi-Beam Atmospheric Transceiver (COMBAT) experiments is that the measurements of the atmospheric-turbulence induced laser beam intensity scintillations at the receiver telescope aperture were obtained simultaneously using three laser sources (laser beacons) with different wavelengths (λ1 = 0.53 μm, λ2 = 1.06 μm, and λ3 = 1.55 μm). The presented experimental results on …

Adaptive Multicast On Mobile Ad Hoc Networks Using Tree-Based Meshes With Variable Density Of Redundant Paths, Sangman Moh, Sang Jun Lee, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Multicasting has been extensively studied for mobile ad hoc networks (MANETs) because it is fundamental to many ad hoc network applications requiring close collaboration of multiple nodes in a group. A general approach is to construct an overlay structure such as multicast tree or mesh and to deliver a multicast packet to multiple receivers over the overlay structure. However, it either incurs a lot of overhead (multicast mesh) or performs poorly in terms of delivery ratio (multicast tree). This paper proposes an adaptive multicast scheme, called tree-based mesh with k-hop redundant paths (TBM _k ), …

Scene-Based Nonuniformity Correction With Reduced Ghosting Using A Gated Lms Algorithm, Russell C. Hardie, Frank Orion Baxley, Brandon J. Brys, Patrick C. Hytla

Electrical and Computer Engineering Faculty Publications

In this paper, we present a scene-based nouniformity correction (NUC) method using a modified adaptive least mean square (LMS) algorithm with a novel gating operation on the updates. The gating is designed to significantly reduce ghosting artifacts produced by many scene-based NUC algorithms by halting updates when temporal variation is lacking. We define the algorithm and present a number of experimental results to demonstrate the efficacy of the proposed method in comparison to several previously published methods including other LMS and constant statistics based methods. The experimental results include simulated imagery and a real infrared image sequence. We show that …

Design Of Acousto-Optic Chaos Based Secure Free-Space Optical Communication Links, Anjan K. Ghosh, Pramode K. Verma, Samuel Cheng, Robert C. Huck, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

We discuss the design of an acousto-optic cell based free space optical communication link where the data beam is made secure through chaos encryption. Using external signal modulation of the diffracted light from a hybrid acousto-optic cell chaos (or directly via incorporation in the sound-cell driver's bias voltage) encryption of data is possible. We have shown numerically that decryption of the encoded data is possible by using an identical acousto-optic system in the receiver.

Design And Implementation Of A Byzantine Fault Tolerance Framework For Web Services, Wenbing Zhao

Electrical and Computer Engineering Faculty Publications

Many Web services are expected to run with high degree of security and dependability. To achieve this goal, it is essential to use a Web services compatible framework that tolerates not only crash faults, but Byzantine faults as well, due to the untrusted communication environment in which the Web services operate. In this paper, we describe the design and implementation of such a framework, called BFT-WS. BFT-WS is designed to operate on top of the standard SOAP messaging framework for maximum interoperability. It is implemented as a pluggable module within the Axis2 architecture, as such, it requires minimum changes …

Proactive Service Migration For Long-Running Byzantine Fault-Tolerant Systems, Wenbing Zhao, H. Zhang

Electrical and Computer Engineering Faculty Publications

A proactive recovery scheme based on service migration for long-running Byzantine fault-tolerant systems is described. Proactive recovery is an essential method for ensuring the long-term reliability of fault-tolerant systems that are under continuous threats from malicious adversaries. The primary benefit of our proactive recovery scheme is a reduced vulnerability window under normal operation. This is achieved in two ways. First, the time-consuming reboot step is removed from the critical path of proactive recovery. Second, the response time and the service migration latency are continuously profiled and an optimal service migration interval is dynamically determined during runtime based on the observed …

Minimizing Spatial And Time Reservation With Collision-Aware Dcf In Mobile Ad Hoc Networks, Lubo Song, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Carrier sensing is widely adopted in wireless communication to protect data transfers from collisions. For example, distributed coordination function (DCF) in IEEE 802.11 standard renders a node to defer its communication if it senses the medium busy. For the duration of deferment, each frame carries, in its MAC header, a 16-bit number in microseconds during which any overhearing node must defer. However, even if the carrier signal is detected, both ongoing and a new communication can be simultaneously successful depending on their relative positions in the network or equivalently, their mutual interference level. Supporting multiple concurrent communications is …

Inhibition Of Linear Absorption In Opaque Materials Using Phase-Locked Harmonic Generation, Marco Centini, Vito Roppo, Eugenio Fazio, Federico Pettazzi, Concita Sibilia, Joseph W. Haus, John V. Foreman, Neset Akozbek, Mark J. Bloemer, Michael Scalora

Electrical and Computer Engineering Faculty Publications

We theoretically predict and experimentally demonstrate inhibition of linear absorption for phase and group velocity mismatched second- and third-harmonic generation in strongly absorbing materials, GaAs, in particular, at frequencies above the absorption edge.

A 100-fs pump pulse tuned to 1300 nm generates 650 and 435 nm second- and third-harmonic pulses that propagate across a 450−μm-thick GaAs substrate without being absorbed.

We attribute this to a phase-locking mechanism that causes the pump to trap the harmonics and to impress on them its dispersive properties.

Modeling And Characterization Of Adaptive Lanthanum-Modified Lead Zirconate Titanate (Plzt) Microlenses, Yasser A. Abdelaziez, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We report the modeling and characterization of adaptive voltage controlled electro-optic microlenses. First, we utilize finite element analysis (FEA) to simulate the induced electro-optic effect in lanthanum-modified lead zirconate titanate (PLZT). FEA simulation provides microlens parameters such as phase and focal length. A simple z-scan method is developed to fully characterize the adaptive voltage controlled linear lens. Experimental z-scan results are shown to match the theoretical predictions from FEA.

Tailoring Metallodielectric Structures For Superresolution And Superguiding Applications In The Visible And Near-Ir Ranges, Domenico De Ceglia, Maria Antonietta Vincenti, M. G. Cappeddu, Marco Centini, Neset Akozbek, Antonella D'Orazio, Joseph W. Haus, Mark J. Bloemer, Michael Scalora

Electrical and Computer Engineering Faculty Publications

We discuss propagation effects in realistic, transparent, metallodielectric photonic band gap structures in the context of negative refraction and super-resolution in the visible and near infrared ranges. In the resonance tunneling regime, we find that for transverse-magnetic incident polarization, field localization effects contribute to a waveguiding phenomenon that makes it possible for the light to remain confined within a small fraction of a wavelength, without any transverse boundaries, due to the suppression of diffraction. This effect is related to negative refraction of the Poynting vector inside each metal layer, balanced by normal refraction inside the adjacent dielectric layer: The degree …

A Reservation-Based Extended Transaction Protocol, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith

Electrical and Computer Engineering Faculty Publications

With the advent of the new generation of Internet-based technology, in particular, web services, the automation of business activities that are distributed across multiple enterprises becomes possible. Business activities are different from traditional transactions in that they are typically asynchronous, loosely coupled, and long running. Therefore, extended transaction protocols are needed to coordinate business activities that span multiple enterprises. Existing extended transaction protocols typically rely on compensating transactions to handle exceptional conditions. In this paper, we identify a number of issues with compensation-based extended transaction protocols and describe a reservation-based extended transaction protocol that addresses those issues. Moreover, we define …

Examination Of Energy And Group Velocities In Positive And Negative Index Chiral Materials With And Without Dispersion, Monish Ranjan Chatterjee, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Concepts of energy and group velocities, Poynting and propagation vectors are examined for both positive and negative index materials. Known definitions for these entities are explored in terms of the interplay of chirality and dispersion.

Analysis Of Beam Propagation In 90-Degree Holographic Recording And Readout Using Transfer Functions And Numerical 2-D-Laplace Inversion, Monish Ranjan Chatterjee, Partha P. Banerjee, George Nehmetallah

Electrical and Computer Engineering Faculty Publications

Recently, 2-D-Laplace analysis of recording and readout of edge-holograms was reported. Numerical Laplace inversion was examined for simple test cases. Inversion algorithms are applied to examine beam shaping and distortion in photovoltaic and photorefractive materials.

Maximizing Communication Concurrency Via Link-Layer Packet Salvaging In Mobile Ad Hoc Networks, Chansu Yu, Kang G. Shin, Lubo Song

Electrical and Computer Engineering Faculty Publications

Carrier-sense medium access control (MAC) protocols such as the IEEE 802.11 distributed coordination function (DCF) avoid collisions by holding up pending packet transmission requests when a carrier signal is observed above a certain threshold. However, this often results in unnecessarily conservative communication, thus making it difficult to maximize the utilization of the spatial spectral resource. This paper shows that a higher aggregate throughput can be achieved by allowing more concurrent communications and adjusting the communication distance on the fly, which needs provisions for the following two areas. On the one hand, carrier sense-based MAC protocols do not allow aggressive communication …

Atmospheric Turbulence Compensation Of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique On Amos 3.6 M Telescope, Mikhail Vorontsov, Jim F. Riker, Gary W. Carhart, Venkata S. Rao Gudimetla, Leonid A. Beresnev, Thomas Weyrauch

Electrical and Computer Engineering Faculty Publications

The Stochastic Parallel Gradient Descent Technique-based Adaptive Optics (SPGD-AO) system described in this presentation does not use a conventional wavefront sensor. It uses a metric signal collected by a single pixel detector placed behind a pinhole in the image plane to drive three deformable mirrors (DMs). The system is designed to compensate the image for turbulence effects. The theory behind this method is described in detail in [1]. However this technique, while widely simulated and tested in the laboratory, was not yet verified in astronomical field site experiments. During the month of May 2007, a series of experiments with SPGD-AO …