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Accurate measurement circuit and high-frequency sensors with sufficient bandwidth are necessary for the analysis of individual partial discharge (PD) pulses. In this paper, a testbed is designed and constructed for the investigation of DC PD pulses. The testbed is equipped with a 50 ohm transmission line (TL) that terminate to an oscilloscope for measuring the charge displacement current generated by PD pulses. Besides the oscilloscope measurements, two types of electromagnetic field sensors (D-dot and B-dot) were developed to capture the EM fields of the PD pulses propagating through the TL. The main goal of this paper is to investigate the DC PD pulses through the EM fields and the corresponding discharge current pulses that are considered as calibrating signals for the developed D-dot and B-dot sensors. The results of DC cavity discharge measured by the constructed testbed and the EM field sensors demonstrate close agreement with the reference PD pulses measured via oscilloscope.

A finite-difference frequency-domain (FDFD) solver, based on the quasi-TEM approximation, is analyzed to determine the validity of the quasi-TEM approximation as a function of frequency. A full-wave finite-difference time-domain characteristics in a transmission line structure (stripline) at frequencies in the vicinity of the lowest waveguide mode cutoff frequency. Results show that the transverse fields in the stripline are near constant over a wide range of frequencies, even at frequencies above the dominant waveguide mode cutoff frequency.

The shift-invariant properties of the redundant discrete wavelet transform (RDWT) produce spatial correlation between adjacent scales for significant features of a signal. In previous work, edges were detected in medical imaging based directly on the locations of high correlation. The technique presented in this work follows the same principle of spatial correlation between adjacent scales to identify interference in target detection of range-Doppler map applications. A filtering technique is presented to determine the location of interfering targets in constant false alarm rate (CFAR) detection and remove them as a means to reduce mutual target masking. In this paper, the filtering technique is applied to radar detection of 2-D range-Doppler maps produced by LFM pulse-Doppler radar. A CFAR detection algorithm using this filtering technique is presented and the performance is compared with other robust CFAR detectors. It is shown that the proposed CFAR detector utilizing the interference filtering technique performs better in suppressing target masking when compared to the other CFAR detectors.

This study aims to classify and compare AC and DC partial discharge (PD) based on PD pulse waveform analysis. To achieve this goal, we designed a testbed that enables precise measurements of individual PD pulses. The testbed is used for collecting data from four different types of PDs including cavity, surface, corona, and floating potential discharges generated by individual PD source samples. All samples were examined under AC, positive DC, and negative DC electrical stresses, through which we captured thousands of PD pulses. We classify the waveforms of each PD type into representative groups associated to their discharge mechanisms. The statistical data of the measured pulses are utilized to identify the differences between AC and DC PDs while the clustered patterns of PD amplitude versus their temporal characteristics serve as a means to classify the types of PDs under AC and DC electrical stresses.

A finite-difference frequency-domain (FDFD) solver applicable to quasi-TEM applications is defined. The FDFD solver is applicable to a wide variety of transmission line structures where the cross-sectional dimensions govern the frequency range over which the quasi-TEM approximation is valid. The quasi-TEM FDFD solver provides an efficient solution for conductor current distributions involving both skin effect and proximity effect. Simulation results obtained using the quasi-TEM FDFD solver are compared to measurements and other numerical methods.

In this dissertation, image feature extraction quality is enhanced through the introduction of two feature learning techniques and, subsequently, feature-level fusion strategies are presented that improve classification performance. Two image/signal processing techniques are defined for pre-conditioning image data such that the discriminatory information is highlighted for improved feature extraction. The first approach, improved Evolution-COnstructed features, employs a modified genetic algorithm to learn a series of image transforms, specific to a given feature descriptor, for enhanced feature extraction. The second method, Genetic prOgramming Optimal Feature Descriptor (GOOFeD), is a genetic programming-based approach to learning the transformations of the data for feature extraction. GOOFeD offers a very rich and expressive solution space due to is ability to represent highly complex compositions of image transforms through binary, unary, and/or the combination of the two, operators. Regardless of the two techniques employed, the goal of each is to learn a composition of image transforms from training data to present a given feature descriptor with the best opportunity to extract its information for the application at hand. Next, feature-level fusion via multiple kernel learning (MKL) is utilized to better combine the features extracted and, ultimately, improve classification accuracy performance. MKL is advanced through the introduction of six new indices for kernel weight assignment. Five of the indices are measured directly from the kernel matrix proximity values, making them highly efficient to compute. The calculation of the sixth index is performed explicitly on distributions in the reproducing kernel Hilbert space. The proposed techniques are applied to an automatic buried explosive hazard detection application and significant results are achieved.

A detailed formulation is provided for an efficient finite-difference frequency-domain (FDFD) scheme which is applicable to low-frequency structures where the quasi-TEM approximation is valid. The FDFD scheme is applied to large cross-section low-frequency transmission line structures where both skin effect and proximity effect are present. Results are compared to measurements and other numerical methods.

Oriented strandboard (OSB) is a wood-based composite product with the largest market share for residential and commercial construction. Reliable in-line nondestructive evaluation devices are needed to rapidly determine OSB panel moisture content (MC) and specific gravity (SG) after hot pressing. In this report a radio frequency (RF) scanning technique was used to evaluate the MC and SG of OSB. RF scanning apparatuses were built to test OSB specimens at various MC and SG levels. Statistical models of the results were generated with the multiple linear regression method for estimating OSB MC and SG. The results indicated that the MC and SG of OSB can be estimated using RF responses in using voltage attenuation and signal phase shift.

Reports on the IEEE Special Interest Group on Humanitarian Technology (SIGHT) program, a network of volunteers from around the globe that teams with underserved communities and local organizations to leverage technology for sustainable development.

If a job search is in your near future, you should take advantage of the IEEE ResumeLab. Much more than a highly effective resume builder, the IEEE ResumeLab is actually a diverse suite of career management tools. In addition to the professional resume builder, the suite contains a portfolio builder; training in interview skills; tools to assist in writing effective letters, developing a video resume, and skills assessment; and a website builder for the online presentation of proficiencies and abilities.

A fast method for determining the fields scattered from a perfect electric conductor (PEC) strip or PEC semicircular cylinder loaded with semicircular dielectric cylinders illuminated by a TE/TM plane wave or an electric/magnetic line source is presented. The method is based on expanding the field on the circle containing the scatterer in terms of a Neumann series, which satisfies the continuity of the tangential electric field. The continuity of the tangential magnetic field is satisfied by using the orthogonality of Gegenbauer polynomials. Some numerical results are presented to demonstrate the efficacy of the proposed solution.

This paper describes an experiment that demonstrates Gauss’s law for electric fields. The experiment utilizes easily obtained equipment and requires simple electrostatic field measurements. The field measurements are obtained for azimuthally symmetric electrodes located over a conducting ground plane. The measurements are shown to be consistent with the image theory solution for a spherical electrode over a ground plane. The relation between Gauss’s law and the concept of capacitance is also demonstrated.

The simulation of 60 Hz current distributions on non-segregated phase bus structures requires that both the skin effect and the proximity effect be modeled accurately, given the large currents flowing on the three-phase bus bars in close proximity, which are normally configured in a side-by-side configuration. The phase bus conductors are assumed to be air insulated and a conducting enclosure is assumed for the non-segregated phase bus system. The simultaneous impacts of skin effect and proximity effect on the bus bar current distributions preclude the use of simple skin effect approximations when analyzing the bus performance relative to conductor heating in an attempt to eliminate hot spots.

The IEEE's Student Professional Awareness Experience (SPAx) program is aimed at developing key nontechnical skills that are crucial for success in the workplace but are not taught in the classroom. Engineering is broader than the various technical skills covered in the typical engineering curriculum. Nontechnical competencies are just as critical to engineers as their technical training. The student professional awareness activities of the SPAx program are oriented to enhance the leadership, career, and professional development skills of engineering students.

Summary form only given. A finite-difference frequency-domain (FDFD) scheme is implemented to solve for 60 Hz current distributions in non-segregated phase bus structures commonly used in high voltage connections such as (1) switchgear to switchgear (2) switchgear to transformers and (3) generators to auxiliary compartments. The three-phase bus bars in these applications, normally configured in a side-by-side configuration, carry large currents in close proximity. Thus, the current distributions on the bus bars are simultaneously impacted by the skin effect and the proximity effect, so that simple approximations based solely on the skin effect are inaccurate. Accurate models of the bus bar current distributions are required to design the non-segregated phase bus such that excessive conductor heating is prevented.A FDFD scheme is selected to simulate the bus bar current distributions due to the low-frequency limitation of the commonly-used finite-difference time-domain (FDTD) scheme. Highly resolved structures containing fine grids require very small time-steps in FDTD simulations that make a low-frequency solution impractical. Only the spatial variation of the current is involved in the single frequency FDFD solution, which yields an efficient solution scheme at lowfrequency. The FDFD formulation is implemented as a two-dimensional solution appropriate for the current distributions away from the ends of the bus bars. Maxwell's equations are manipulated into a modified wave equation for the electric field given the imperfectly conducting and nonmagnetic bus bars that are air-insulated. Simple finite-difference approximations to the spatial derivatives of the governing differential equation are incorporated and continuity of the tangential electric field is enforced at all air-conductor interfaces. A conducting enclosure is assumed for the non-segregated phase bus system. Examples of bus bar current distributions are presented for different geometries of interest. The interaction of the proximity and skin effects in the bus bar current distributions are examined for different conductor spacings.

The effects of wall moisture on the characteristics of matched illumination waveforms for use in through the wall radar imaging (TWRI) are examined via simulation. Various wall moisture profiles are considered for solid adobe-like walls including a uniform moisture profile, moisture concentrated in the interior region of the wall, and moisture concentrated at the exterior surface. Specific characteristics of the typical optimum waveform are noted for each of the moisture profiles considered. Techniques for experimentally validating the performance of the matched illumination waveforms are also summarized.

All three spectral sums in the cylindrical harmonic eigenfunction expansion of the Lorentz gauge-free space magnetic vector potential dyadic Green's function are closed. The specific techniques used to close the radial, azimuthal, and axial spectral sums are detailed. The magnetic vector potential dyadic Green's function spectral closure process is paralleled with that of the corresponding scalar Green's function eigenfunction expansion. Fundamental relationships between the scalar and dyadic spectral closures are noted. The cancellation of static and traveling wave pole contributions is noted in order to achieve reduced expressions at each stage of the spectral closure process. The techniques used here to close the spectral sums in the free space eigenfunction expansion are also applicable to certain scattering geometries when the method of scattering superposition is employed. Thus, the complexity of the dyadic Green's function computation may be reduced.

As an emerging technology, autonomous Unmanned Vehicle Systems (UVS) have found not only many military applications, but also various civil applications. For example, Google, Amazon and Facebook are developing their UVS plans to explore new markets. However, there are still a lot of challenging problems which deter the UVSs development. We study two important and challenging problems in this dissertation, i.e. localization and 3D reconstruction. Specifically, most GPS based localization systems are not very accurate and can have problems in areas where no GPS signals are available. Based on the Received Signal Strength Indication (RSSI) and Inertial Navigation System (INS), we propose a new hybrid localization system, which is very efficient and can account for dynamic communication environments. Extensive simulation results demonstrate the efficiency of the proposed localization system. Besides, 3D reconstruction is a key problem in autonomous navigation and hence very important for UVS. With the help of high-speed Internet and powerful cloud servers, the light-weight computers on the UVS can now execute computationally expensive computer vision based algorithms. We develop a 3D reconstruction scheme which employs cloud computing to perform realtime 3D reconstruction. Simulations and experiments show the efficacy and efficiency of our scheme.

A reduced size antiresonant antenna for underground object detection is presented. The reduced size antenna is shown to provide improved differential impedance properties to that of a full size antiresonant dipole while providing a factor of eight reduction in the maximum dimension of the antenna.

Improvements in through-the-wall radar imaging (TWRI) rely on understanding the phenomenology of the interaction between the radar signal and the wall structure. Propagation of the pulse through the wall adversely affects the resulting target return signatures through attenuation and time dispersion. One technique of improving TWRI performance is through optimal waveform design. The matched illumination concept has been shown to improve target detection and discrimination for TWRI by optimally shaping the transmission waveform to maximize the signal-to-interference and noise ratio of the radar's transmitter-receiver pair [H. Estephan et.al, IEEE Trans. on Geoscience and Remote Sensing, Vol. 48, No. 7, pp. 2930-2941, 2010].

Small antennas are absolutely essential for implantable medical telemetry systems since they dictate the overall size of the system. Earlier, we designed a miniaturized implantable antenna based on the leaky wave properties of the wave travelling along the interface (which happens in case of a slot along the interface) between two different dielectric media. The leaky wave is radiated in the medium with higher wave number. The property is extremely useful for implantable antennas since the dielectric properties of biological tissues are extremely high. The designed antenna had dimensions of 10mm × 12 mm × 1mm and was printed on FR4 substrate. This antenna is not biocompatible and it can be made so by coating the antenna with biocompatible materials like silica (er=3.8). Coating the antenna with permittivity less than FR4 does not produce leaky waves and hence no radiation. This problem can be averted by coating the antenna with a higher permittivity biocompatible material. The additional layer complicates the antenna design in addition to increasing the size of the implant.

The changes in input impedance for a simple antenna or transmission line located over a soil containing a conducting object are examined near antiresonance. The near-field coupling of the underground object to the antenna or transmission line is investigated using the complex Poynting vector in order to identify the contribution of traveling and/or standing waves.

Epsilon-near-zero (ENZ) narrow channels inspired by super coupling are proposed to (1) match two dissimilar coaxial lines, (2) match a coaxial line to a rectangular waveguide and (3) to implement a directional coupler. The designs presented here are inherently narrowband in operation, but broadband implementation is possible using cascaded sections as presented in [10].

When utilizing an antenna over ground as a near-field probe for detecting underground conducting objects, maximizing the variation in the antenna input impedance due to the buried object is the primary concern. Using the example of a horizontal dipole and a buried cylinder, significant variation in the dipole input impedance is obtained by carefully positioning the antiresonant dipole to excite the dominant cylinder resonance.

A simple horizontal dipole over ground can be used as a near-field probe for buried object detection if changes in the dipole impedance produced by the presence of the buried object can be correlated to the characteristics of the object. In this paper, the wideband variation in the input impedance of a horizontal dipole over ground caused by the presence of a nearby underground anomaly (tunnel) is investigated via finite difference time-domain (FDTD) simulation. The correlation of the periodic variation in the dipole impedance difference to the location of the tunnel is demonstrated.

Oriented strandboard (OSB) is a wood composite product with the largest market share in U.S. residential and commercial construction. Wood specific gravity (SG) and moisture content (MC) play an important role in the OSB manufacturing process. They are the two of the critical variables that manufacturers are required to monitor, locate, and control in order to produce a product with consistent quality. In this study, radio frequency scanning nondestructive evaluation (NDE) technologies evaluated the local area MC and SG of OSB panels following panel production by hot pressing. A finite element software simulation tool was used to optimize the sensor geometry and for investigating the interaction between electromagnetic field and wood dielectric properties. Our results indicate the RF scanning response is closely correlated to the MC and SG variations in OSB panels. Radio frequency NDE appears to have potential as an effective method for insuring OSB panel quality during manufacturing.