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- Imaging systems (4)
- Radar (4)
- Borehole (3)
- FDTD (3)
- Ground penetrating radar (3)
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- Algorithms (2)
- Computer simulation--Technological innovations (2)
- FDFD (2)
- GPR (2)
- Improvised explosive devices - Detection (2)
- PML (2)
- SAMM (2)
- Three-dimensional imaging (2)
- 2D FDTD Model (1)
- Antenna radiation patterns (1)
- Antennas (1)
- Bombs (1)
- Bosnian soil (1)
- Bridge decks (1)
- CWR (1)
- Cancer--Diagnosis (1)
- Cancer--Treatment--Technological innovations (1)
- Civil Infrastructure (1)
- Computer aided simulation (1)
- Conductivity (1)
- Confocal Microscope (1)
- Confocal microscopy (1)
- Contamination (1)
- Cross Borehole Radar (1)
- Cross Well Radar (1)
Articles 1 - 18 of 18
Full-Text Articles in Engineering
Forward Time Domain Ground Penentrating Radar Modeling Of Bridge Decks For Detecting Deterioration, Kimberly Belli, Sara J. Wadia-Fascetti, Carey Rappaport
Forward Time Domain Ground Penentrating Radar Modeling Of Bridge Decks For Detecting Deterioration, Kimberly Belli, Sara J. Wadia-Fascetti, Carey Rappaport
Carey Rappaport
Ground penetrating radar (GPR) for nondestructive testing is a relatively young technology, especially with application to civil infrastructure such as bridges and roadways. Conventional methods of processing and analyzing GPR data for civil infrastructure are often qualitative, using relative reflection amplitude from subsurface boundaries or reinforcing steel (rebars) as an indicator of health. This poster brings well understood electrical engineering analysis tools to the application of nondestructive testing of bridges using GPR. Using iterative forward modeling to improve upon conventional permittivity and depth calculations, a computational model geometry is computed for the assumed bridge deck with no anomalies present. A …
Bomdetec - Wide Area Surveillance And Suicide Bomber Detection, John Beaty, Richard Sullivan, Carey M. Rappaport
Bomdetec - Wide Area Surveillance And Suicide Bomber Detection, John Beaty, Richard Sullivan, Carey M. Rappaport
Carey Rappaport
Amidst the manifold threats currently afflicting society, that of body-worn explosives is significant if not altogether paramount. Veiled under layers of clothing by individual suicide bombers, these explosives are often constructed of non-standard parts, making detection at a safe distance difficult. It behooves us to develop a detection system capable of locating such explosives at distances sufficient to prevent suicide bombers from approaching densely populated or strategically important areas. Funded by the Department of Homeland Security, the intent of this project is to synthesize four technologies--intelligent video, radar, X-ray, and terahertz--into one surveillance system for suicide bomber detection. Ideally, bombers …
Characterization Of Anomaly In Dispersive Background With Random Rough Surface, Reza Firoozabadi, Eric L. Miller, Carey M. Rappaport, Ann W. Morgenthaler
Characterization Of Anomaly In Dispersive Background With Random Rough Surface, Reza Firoozabadi, Eric L. Miller, Carey M. Rappaport, Ann W. Morgenthaler
Carey Rappaport
This work addresses the subsurface imaging of the buried lossy dielectric objects embedded in the dispersive lossy background with unknown rough surface using the data collected by ground penetrated radar. The applications of this problem range from environmental monitoring to nondestructive testing. An iterative inversion algorithm is proposed to reconstruct the geometry and dielectric parameters of the half-space ground as well as the buried object. This approach utilizes the efficient numerical Levenberg-Marquardt algorithm to update the unknowns from a judicious initial guess of boundaries modeled by parametric B-spline curves as well as dielectric parameters. Our approach is based on the …
Wave-Based Modeling, Highlighting Underground Sensing And Imaging, Carey Rappaport, Sara Wadia-Fascetti, Miriam Leeser
Wave-Based Modeling, Highlighting Underground Sensing And Imaging, Carey Rappaport, Sara Wadia-Fascetti, Miriam Leeser
Carey Rappaport
No abstract provided.
Matlab-Based Finite Difference Frequency-Domain Method For Microwave Breast Imaging, Qiuzhao Dong, Carey Rappaport
Matlab-Based Finite Difference Frequency-Domain Method For Microwave Breast Imaging, Qiuzhao Dong, Carey Rappaport
Carey Rappaport
The FDFD electromagnetic model computes wave scattering by directly discretizing 's equations along with specifying the material characteristics in the scattering volume. No boundary conditions are need except for the outer grid termination absorbing boundary. We use a sparse matrix Matlab code with loose generalized minimum residue (LGMRES) Krylov subspace iterative method to solve the large sparse matrix equation, along with the Perfectly Matched Layer (PML) absorbing boundary condition. The PML conductivity profile employs the empirical optimal value from[1-2]. This method is easily manipulated and general-geometry oriented, it is fast comparing to other models for solving the whole 3D computational …
Cross-Well Radar I: Experimental Simulation Of Cross-Well Tomography And Validation, Arvin Farid, Akram N. Alshawabkeh, Carey M. Rappaport
Cross-Well Radar I: Experimental Simulation Of Cross-Well Tomography And Validation, Arvin Farid, Akram N. Alshawabkeh, Carey M. Rappaport
Carey Rappaport
This paper explains and evaluates the potential and limitations of conducting Cross-Well Radar (CWR) in sandy soils. Implementing the experiment and data collection in the absence of any scattering object, and in the presence of an acrylic plate (a representative of dielectric objects, such as DNAPL (dense non-aqueous phase liquid) pools, etc.), as a contrasting object in a water-saturated soil is also studied. To be able to image the signature of any object, more than one pair of receiving and transmitting antennas are required. The paper describes a method to achieve repeatable, reliable, and reproducible laboratory results for different transmitter-receiver …
The Semi-Analytic Mode Matching (Samm) Algorithm For Efficient Computation Of Nearfield Scattering In Lossy Ground From Borehole Sources, Ann W. Morgenthaler, He Zhan, Carey M. Rappaport
The Semi-Analytic Mode Matching (Samm) Algorithm For Efficient Computation Of Nearfield Scattering In Lossy Ground From Borehole Sources, Ann W. Morgenthaler, He Zhan, Carey M. Rappaport
Carey Rappaport
The three dimensional semi-analytic mode matching (SAMM) algorithm is used to determine nearfield scattering from underground targets in lossy soil, where the source is a dipole placed within a borehole in the ground. Scattering is described by moderately low-order superpositions of spherical modes placed at multiple user-specified coordinate scattering centers (CSCs), the mode coefficients are found numerically by least-squares fitting all boundary conditions at discrete points along the relevant interfaces while at the same time obeying radiation conditions. SAMM results are compared with a completely different method: the Half-Space Born Approximation (HSBA). Good agreement between methods serves to validate both …
Suicide Bomber Detection Using Millimeter-Wave Radar, Richard Sullivan, Morgan Galaznik, Jose Ángel Martinez-Lorenzo, Carey M. Rappaport
Suicide Bomber Detection Using Millimeter-Wave Radar, Richard Sullivan, Morgan Galaznik, Jose Ángel Martinez-Lorenzo, Carey M. Rappaport
Carey Rappaport
Amidst the manifold threats currently afflicting public welfare, that of body-worn explosives is significant if not altogether paramount. Commonly referred to as ""suicide bombers,"" the bearers of body-worn, improvised explosive devices (IEDs) enter crowded public areas in order to detonate the IDE, inflicting lethal damage to themselves and surrounding individuals. Constructed of non-standard parts and veiled under layers of clothing, these body-worn IEDs go frequently undetected. The aim of this research is to examine the feasibility of using millimeter-wave (MMW) radar to detect body-worn IEDs at distances up to 50 meters. In order to achieve a beamwidth capable of illuminating …
Reflector Antenna Discrete Distortion Determination : An Iterative-Field-Matrix Solution, José Ángel Martinez-Lorenzo, Carey M. Rappaport
Reflector Antenna Discrete Distortion Determination : An Iterative-Field-Matrix Solution, José Ángel Martinez-Lorenzo, Carey M. Rappaport
Carey Rappaport
The idealized shapes of satellite reflector antennas are often distorted once they are placed in orbit. The performance of such antennas can be improved by identifying the locations and amount of their surface distortions and then by correcting them using active surface distortion or array feeding. This work presents a method to determine the required discrete surface distortions to correct errors. The algorithm starts by discretizing the entire reflector surface into triangular patches, then by finding a linear relationship between the local distortion and the difference of the distorted and undistorted farfields patterns. A linear system of equations with the …
Bimodal Detection Of Underground Contamination In Two Dimensional Systems, Maria Fernanda Serrano G., Ingrid Padilla, Rafael Rodriguez Solis, Carey Rappaport
Bimodal Detection Of Underground Contamination In Two Dimensional Systems, Maria Fernanda Serrano G., Ingrid Padilla, Rafael Rodriguez Solis, Carey Rappaport
Carey Rappaport
An environmental issue that has reached interest in the academic and industry is groundwater contamination. Moreover, government agencies are concerned, for example, about the widespread of dense non-aqueous phase liquids (DNAPLs) in the underground due to incorrect disposal of this substance. Over the last five years we have done a great effort to enhance Cross Well Radar as a technology for detection of compounds which can be used to predict the mobility and persistence of chemicals in the unsaturated near surface. Image acquisition and processing has also been applied for contaminant detection and monitoring. In this poster, we describe a …
Experimental Validation Of A Numerical Forward Model For Tunnel Detection Using Cross-Borehole Radar, Arvin Farid, Jose A. Martinez-Lorenzo, Akram N. Alshawabkeh, Carey M. Rappaport
Experimental Validation Of A Numerical Forward Model For Tunnel Detection Using Cross-Borehole Radar, Arvin Farid, Jose A. Martinez-Lorenzo, Akram N. Alshawabkeh, Carey M. Rappaport
Carey Rappaport
The goal of this research is to develop an experimentally validated twodimensional (2D) finite difference frequency domain (FDFD) numerical forward model to study the potential of radar-based tunnel detection. Tunnel detection has become a subject of interest to the nation due to the use of tunnels by illegal immigrants, smugglers, prisoners, assailants, and terrorists. These concerns call for research to nondestructively detect, localize, and monitor tunnels. Nondestructive detection requires robust image reconstruction and inverse models, which in turn need robust forward models. Cross-Well Radar (CWR) modality is used for experimentation to avoid soil-air interface roughness. CWR is not a versatile …
The Semi-Analytic Mode Matching (Samm) Algorithm For Efficient Computation Of Near Field Scattering From Borehole Antennas In Lossy Ground, Ann W. Morgenthaler, He Zhan, Carey M. Rappaport
The Semi-Analytic Mode Matching (Samm) Algorithm For Efficient Computation Of Near Field Scattering From Borehole Antennas In Lossy Ground, Ann W. Morgenthaler, He Zhan, Carey M. Rappaport
Carey Rappaport
The 3D semi-analytic mode matching (SAMM) algorithm is used to determine nearfield scattering from realistic targets buried in lossy, possibly rough soil where the source is a dipole placed within a borehole in the ground. SAMM has been successfully implemented as a forward model for inverse scattering algorithms, and can be used as a GPR design tool which is both cheaper and more efficient than experimentation. SAMM can be (and has been) used for geophysical, medical, and biological applications, including mine detection, pollution detection, microwave tumor detection. Other possible applications that could utilize SAMM are cell structure characterization, wall penetrating …
Fdtd Simulation Of A Confocal Microscope Using A Theta Line Scan, Blair Simon, Charles Dimarzio, Milind Rajadhyaksha, Carey Rappaport
Fdtd Simulation Of A Confocal Microscope Using A Theta Line Scan, Blair Simon, Charles Dimarzio, Milind Rajadhyaksha, Carey Rappaport
Carey Rappaport
We describe a 2-D computational model of the optical propagation in human skin from a confocal reflectance theta microscope. As an effect of decreasing the size of the microscope so that it is more clinically useful, the usual point source and detector with a raster scan is changed to a line source with a 1-D array detector. Because there is only one dimension of scanning, the microscope is confocal in one direction, but not in the other, however, this results in additional localized decreases in signal. We hypothesize that these result from the interaction of the bi-static imaging configuration with …
Introducing The Nufdtd Software Package, Seth Baum, Carey Rappaport
Introducing The Nufdtd Software Package, Seth Baum, Carey Rappaport
Carey Rappaport
FDTD is a successful technique for numerically simulating electromagnetic wave propagation. Our group at Northeastern does research to improve the performance of various aspects of the technique and has built these improvements into its own FDTD software package, "NUFDTD," making the code in some ways more powerful than those available commercially. These improvements include a frequency dispersion model and handling of stratified layers. Recent work (Mr. Baum's Masters thesis) has built this code into a user-friendly software package. This package is currently available via free download and is ready for use by both the academic community and the commercial sector.
Simulating Gpr For Diagnosis Of Civil Infrastructure, Laura Carey, Kimberly Belli, Carey M. Rappaport, Sara J. Wadia-Fascetti
Simulating Gpr For Diagnosis Of Civil Infrastructure, Laura Carey, Kimberly Belli, Carey M. Rappaport, Sara J. Wadia-Fascetti
Carey Rappaport
At the present, a large proportion of our nation's bridges and roadways are falling into disrepair. About 27.5% of U.S. bridges are structurally deficient or functionally obsolete (ASCE, 2001, 2003). Nondestructive testing methods, such as GPR, are becoming more and more important in diagnosing the condition of such concrete structures. GPR is a high-resolution electromagnetic technique used to investigate the immediate subsurface of the earth, building materials, roads, and bridges. This poster shows my work in GPR modeling during a summer undergraduate experience through CenSSIS. A specialized MATLAB toolbox designed by Kim Belli created all data presented here. The use …
Comparison And Application In 3d Matlab-Based Finite-Difference Frequency-Domain Method, Qiuzhao Dong, He Zhan, Ann Morgenthaler, Carey Rappaport
Comparison And Application In 3d Matlab-Based Finite-Difference Frequency-Domain Method, Qiuzhao Dong, He Zhan, Ann Morgenthaler, Carey Rappaport
Carey Rappaport
The FDFD electromagnetic model computes wave scattering by directly discretizing Maxwell's equations along with specifying the material characteristics in the scattering volume. No boundary conditions are need except for the outer grid termination absorbing boundary. We use a sparse matrix Matlab code with generalized minimum residue (GMRES) Krylov subspace iterative method to solve the large sparse matrix equation, along with the Perfectly Matched Layer (PML) absorbing boundary condition. The PML conductivity profile employs the empirical optimal value from[4-6]. The sparse Matlab-based model is about 100 times faster than a previous Fortran-based code implemented on the same Alpha-class supercomputer. The 3D …
Validating Four-Zeros 2d Fdtd Model, Maryam Jalalinia, Carey M. Rappaport
Validating Four-Zeros 2d Fdtd Model, Maryam Jalalinia, Carey M. Rappaport
Carey Rappaport
In this work we model wave propagation in two-dimensional dispersive medium using FDTD (Finite Difference Time Domain) method. For a lossy, dispersive medium, it is significant to model the wave velocity and attenuation over a wide RF bandwidth with a simple and efficient model. Using a four-zeros single-pole rational function of the Z-transform variable (Z = exp(j??t)) to model conductivity with constant real dielectric constant, we generate a discretized time domain equation which matches measured values over more than two decades of frequency. The simulations show that there is a good agreement between measureed and modeled propagation constant and attenuation …
Tunnel Detection Using Cross Borehole Radar, Clay Kurison, Arvin M. Farid, Akram N. Alshawabkeh, Carey M. Rappaport
Tunnel Detection Using Cross Borehole Radar, Clay Kurison, Arvin M. Farid, Akram N. Alshawabkeh, Carey M. Rappaport
Carey Rappaport
Shallow tunnels present both military and homeland security threats. Smugglers with intentions of avoiding border security have turned tunnels into transit routes for trafficking weapons, people, drugs and other illegal materials. Shallow tunnels are also used by prisoners to escape prisons. While drug and human trafficking have long been border concerns, the threat of international terrorism has transformed the effort to detect tunnels into a national security priority. Imminent threats include assailants entering military fortifications by burrowing under buildings, detonation of high grade explosives from foundations of high security facilities, and high level prisoners escaping detention centers through tunnels. Real-time …