| Designing a Sensorless Torque Estimator for Direct Torque Control of an Induction Motor |
Sep-2009 |
87 pages |
| Authors:
Athanasios Tsoutsas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
 | Nowadays, transportation is a major cause of air pollution. Electric propulsion could replace the internal combustion engines of automobiles and reduce the emission of exhaust gases. The propulsion of an electric vehicle requires the design of an accurate electromagnetic torque estimator and an efficient control system in order to control the speed of the vehicle. This concept is conveyed through this thesis. An electromagnetic torque calculator of an induction motor ... |
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| Modeling and Simulation of a Non-Coherent Frequency Shift Keying Transceiver Using a Field Programmable Gate Array (FPGA) |
01-Sep-2008 |
125 pages |
| Authors:
Konstantinos Voskakis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In this thesis, the principals of Software Defined Radio are demonstrated by implementing a Binary Frequency Shift Keying (BFSK) receiver-transmitter in a Field Programmable Gate Array (FPGA). After introducing the theory behind the Non- Coherent BFSK demodulation implemented at the receiver, the design of transmitter and receiver is illustrated. The design environment of choice is Mathworks Simulink and Xilinx System Generator, a dedicated library for Mathworks Simulink. The design is ... |
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| Deriving a Computational Theory of Visual Spatial Attention |
05 FEB 2008 |
3 pages |
| Authors:
GEORGE SPERLING; CALIFORNIA UNIV IRVINE
|
| This research effort developed a computational theory for the control of human attention in two-dimensional visual tasks. Theory and experiments focused on the role of the spatial modulation transfer function for human vision, and on the characteristics and limitations of cortical receptive field processes. |
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| High-Order Methods For Wave Propagation |
JAN 2008 |
72 pages |
| Authors:
Miguel R. Visbal; Scott E. Sherer; Michael D. White; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
|
| In order to meet the demanding accuracy requirements in the simulation of wave propagation phenomena, a numerical approach based on high-resolution spatial schemes is presented. The time-domain AFRL code, FDL3DI, solves either the time-dependent Maxwell's equations (for CEM) or the Euler equations (for acoustics) employing 6th-order accurate compact-differences and low-pass spatial filters of up to 10th-order accuracy. The solver has been made applicable to general curvilinear grids through the incorporation ... |
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| Thrust Measurement of a Split-Path, Valveless Pulse Detonation Engine |
DEC 2007 |
115 pages |
| Authors:
Brady J. Bartosh; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Theory predicts ideal pulse detonation technology offers significant fuel efficiency advantages over ramjet/scramjet architecture within a range from high subsonic to low hypersonic velocities. In practice, Pulse Detonation Engines (PDE) require implementation of loss-inducing techniques such as turbulence-generation devices to achieve and sustain detonation events, which effectively narrows the efficiency gap between the two technologies. Pressure losses associated with such obstacles lower system specific thrust (Isp) and reduce overall system ... |
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| A Follow-up Study on Wireless Power Transmission for Unmanned Air Vehicles |
DEC 2007 |
109 pages |
| Authors:
Leng H. Toh; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis was a continuation in part of a NPS project relating to microwave wireless power transmission for micro air vehicles (MAVs). The concept of using microwaves for transferring power in free space has existed since the beginning of the 20th century. The emphasis of this thesis is the experimental study of powering micro air vehicles via the use of using a microstrip rectenna (rectifying antenna) at 10 GHz. A ... |
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| Inverted Echo Sounder Data Processing Manual |
JUN 2007 |
89 pages |
| Authors:
Maureen Kennelly; Karen Tracey; D. R. Watts; RHODE ISLAND UNIV NARRAGANSETT GRADUATE SCHOOL OF OCEANOGRAPHY
|
| The Inverted Echo Sounder (IES) is an ocean bottom-moored instrument that measures the vertical acoustic travel time (VATT) round-trip from the sea floor to the sea surface and back. The VATT varies principally due to changes in the temperature profile of the water column, making the IES well-suited for monitoring changes in temperature structure and dynamic height (baroclinic signal). Currently, the Model 6.2, a combined IES, data-logger, and acoustic release, ... |
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| Advanced Filters and Components for Power Applications |
31 AUG 2006 |
135 pages |
| Authors:
Timothy C. Neugebauer; Brandon J. Pierquet; David J. Perreault; MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR ELECTROMAGNETIC AND ELECTRONIC SYSTEMS
|
| The objective of the research presented in this report is to improve the high frequency performance of power filters and components by better compensating the parasitic effects of practical components. A major application for this improvement is in design of low pass filters for power electronics, although some other applications are also explored. In power electronics, the input and output filters are the dominant consideration in limiting electromagnetic interference and ... |
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| Infrasound Modeling Using Soviet Explosion Data and Instrument Design Criteria from Experiments and Simulations |
FEB 2006 |
70 pages |
| Authors:
Jeffry L. Stevens; David A. Adams; G. E. Baker; Heming Xu; John R. Murphy; igor Divnov; Vadim N. Bourchik; TITAN CORP SAN LEANDRO CA PULSE SCIENCES DIV
|
| This report covers two major topics: evaluation of International Monitoring System (IMS) network performance using data from historic Soviet nuclear tests and analysis of infrasound instrumentation design. The Institute for the Dynamics of the Geospheres has digitized 220 infrasound waveforms from 22 atmospheric nuclear tests conducted in 1961. We compare measurements from this data set with infrasound scaling and attenuation relations and find best agreement with a relation developed by ... |
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| Position Localization with Impulse Ultra Wide Band |
2005 |
|
| Authors:
Guoping Zhang; S. V. Rao; INSTITUTE FOR INFOCOM RESEARCH (SINGAPORE) RADIO AND COMMUNICATION DEVICE
|
 | In this paper, a low cost UWB-based position localization experiment system is designed and tested in the indoor environment. And a delayed-correlation detector and ultra-highspeed 1bit ADC are proposed to mitigate the estimation error of time difference of arrival (TDOA). And an algorithm using parallel processing and direct path tracking is also proposed to remove the timing-of-arrival (TOA) bias and clock jittering error of TDOA measurement. In our prototype design, ... |
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| Investigation of Outer Length Scale In Optical Turbulence Using an Acoustic Sounder |
SEP 2004 |
53 pages |
| Authors:
Jeffrey T. Douds; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The horizontal separations between convective thermal plumes, and features within a thermal plume, were determined through the use of an acoustic sounder, an anemometer and extensive data analysis. The mean, standard deviation, median and mode were calculated for the computed correlation lengths of the acoustic sounder data sampled in time intervals of 2, 5 and 10 minutes. The data sampled at 2 and 5-minute intervals emphasized features within an individual ... |
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| Selectivity of Local Field Potentials in Macaque Inferior Temporal Cortex |
SEP 2004 |
42 pages |
| Authors:
Gabriel Kreiman; Chou Hung; Tomaso Poggio; James DiCarlo; MASSACHUSETTS INST OF TECH CAMBRIDGE COMPUTER SCIENCE AND ARTIFICIAL INTELLIGENCE LAB
|
| While single neurons in inferior temporal (IT) cortex show differential responses to distinct complex stimuli, little is known about the responses of populations of neurons in IT. We recorded single electrode data, including multi-unit activity (MUA) and local field potentials (LFP), from 618 sites in the inferior temporal cortex of macaque monkeys while the animals passively viewed 78 different pictures of complex stimuli. The LFPs were obtained by low-pass filtering ... |
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| Beamforming for Radar Systems on COTS Heterogeneous Computing Platforms |
20 AUG 2004 |
33 pages |
| Authors:
Jeffrey A. Rudin; MERCURY COMPUTER SYSTEMS INC CHELMSFORDMA
|
| The introduction of high-speed, analog-to-digital converters has resulted in many of the traditional front-end and sub-array combining functions of multi-function, phased-array radar systems being performed in the digital rather than in the analog domain. Due to the intense amount of processing that is required, many of these functions had to be realized in hardware. This was originally accomplished using VLSI ASICs. However, the advent of multi-million, gate field-programmable gate arrays ... |
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| Theoretical and Experimental Study of Micro Air Vehicle Powered by RF signal at 10 GHz |
DEC 2003 |
133 pages |
| Authors:
George Tsolis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The concept of using electromagnetic energy in the form of microwaves for transferring power from one point to another through free space is very old. However, the idea for powering micro air vehicles using microwaves is less than a decade old. This thesis presents a theoretical and experimental study of powering a micro air vehicle, using electromagnetic energy at the frequency of 10 GHz. Two micro air vehicle prototypes were ... |
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| Construction Techniques for LC Highpass and Lowpass Filters Used in the 1 MHz to 1 GHz Frequency Range |
OCT 2003 |
|
| Authors:
W. Martinsen; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION SALISBURY (AUSTRALIA) INFO SCIENCES LAB
|
| This technical note describes construction techniques for building passive LC highpass and lowpass filters whose intended use spans several octaves of bandwidth. It examines limitations in the frequency domain of the two basic components, inductors and capacitors, used to build these filters, the unwanted effects of the distributed reactance of opposite sign to the wanted within these components and the electro-magnetic coupling between these components when used to build a ... |
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| Adjustable Bandwidth Concept (ABC) Performance Evaluation |
JUL 2003 |
44 pages |
| Authors:
Andrew J. Noga; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| Foundational work is presented regarding the objective performance analysis of the Adjustable Bandwidth Concept (ABC) Signal Energy Detector, U.S. Patent 5,257,211. The ABC pre-detection process is an effective method of combining time and frequency domain averaging to enhance the automated spectral survey task. |
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| Automatic Detection Algorithm of Intracranial Pressure Waveform Components |
25 OCT 2001 |
|
| Authors:
Mateo Aboy; James McNames; Brahm Goldstein; PORTLAND STATE UNIV OR
|
| We describe an automated detection algorithm that may be used to identify the percussion peak (P), tidal peak (T), dichrotic notch (N), and dichrotic peak (D) components of the intracranial pressure (ICP) signal. The algorithm uses a moving average filter to remove quantization error, a lowpass filter to identify the beat series, and a local search to identify the components of each beat. The algorithm was compared with two experts' ... |
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| A Multi Channel Chopper Modulated Neural Recording System |
25 OCT 2001 |
|
| Authors:
Mustafa Dagtekin; Wentai Liu; Rizwan Bashirullah; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Presented herein is a fully integrated low-noise CMOS multi-channel amplifier for neural recording applications The circuit employs the chopper modulation technique to reduce the effect of flicker noise and DC offset, A reduced area design implementation is achieved by trading off the increased noise margin performance of the chopper modulator for minimal amplifier area and analog multiplexing of the recording sites, A fully differential topology is used for the signal ... |
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| High-Order Schemes for DNS/LES and CAA on Curvilinear Dynamic Meshes |
AUG 2001 |
12 pages |
| Authors:
M. Visbal; D. Gaitonde; D. Rizzetta; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
|
| In order to reduce the severe computational requirements of standard low-order schemes, higher-order formulations, as well as massively parallel approaches are being actively pursued. Due to their spectral-like resolution and ease of extension to multiple disciplines, high-order compact schemes represent an attractive choice for reducing dispersion, anisotropy and dissipation errors associated with spatial discretizations. Until recently, these schemes have mostly been used in conjunction with explicit time-integration methods to address ... |
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| Discrete Filtering on Unstructured Grids Based on Least-Squares Gradient Reconstruction |
AUG 2001 |
8 pages |
| Authors:
A. Haselbacher; ILLINOIS UNIV AT URBANA CENTER FOR SIMULATION OF ADVANCED ROCKETS
|
| The equations for Large-Eddy Simulation (LES) of turbulent flows are formally derived by applying a low-pass filter to the Navier-Stokes equations. In doing so, it is often tacitly assumed that the filtering and differentiation operations commute. This assumption is invalid if the filter width is not uniform as is the case if wall-bounded flows are computed unless special filter operators are constructed, see, e.g, Vasilyev et at. (1998). The goal ... |
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| Computational Constrains on Large Eddy Simulation of Inhomogeneous Turbulent Complex Geometry Flows |
AUG 2001 |
12 pages |
| Authors:
Oleg V. Vasilyev; MISSOURI UNIV-COLUMBIA
|
| This paper presents a systematic approach for large eddy simulation to be consistent, i.e. to satisfy all the assumptions used in the derivation of the LES equations. We demonstrated that a solution, consistent with the true filtered Navier-Stokes equations, can be achieved by means of explicit filtering. We have shown that explicit filtering not only provides the means for both assessing and minimizing the effects of numerical error in practical ... |
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| A Study of the Effect of Smooth Filtering in LES |
AUG 2001 |
8 pages |
| Authors:
Giuliano de Stefano; Oleg V. Vasilyev; NAPLES UNIV (ITALY) DEPT OF AEROSPACE ENGINEERING
|
| The large eddy simulation equations of turbulent flows are formally derived by applying a low-pass filter to the Navier-Stokes equations. As a result the subgrid-scale stress tensor strongly depends on the assumed filter shape, which causes a subgrid scales model to be filter dependent. Depending on the choice of the filter, the corresponding model should satisfy very different requirements in terms of large scale dynamics and kinetic energy budget. In ... |
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| Covariance Matrix Filtering for Adaptive Beamforming with Moving Interference |
14 MAR 2001 |
7 pages |
| Authors:
Bruce K. Newhall; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An approach is developed for adaptive beamforming for mobile sonars operating in an environment with moving interference from surface shipping. It is assumed that the sound source of each ship is drawn from an ensemble of Gaussian random noise, but each ship moves at constant speed along a deterministic course. An analytic expression for the ensemble mean covariance is obtained. In practice the location, course, speed, mean noise level, and ... |
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| Wavelet Domain Image Interpolation via Statistical Estimation |
2001 |
|
| Authors:
Ying Zhu; Stuart C. Schwartz; Michael T. Orchard; PRINCETON UNIV NJ DEPT OF ELECTRICAL ENGINEERING
|
| We propose a new wavelet domain image interpolation scheme based on statistical signal estimation. A linear composite MMSE estimator is constructed to synthesize the detailed wavelet coefficients as well as to minimize the mean squared error for high-resolution signal recovery. Based on a discrete time edge model we use low-resolution information to characterize local intensity changes and perform resolution enhancement accordingly. A linear MMSE estimator follows to minimize the estimation ... |
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| Fusion of Image Data for Human Understanding Using Array Architectures |
OCT 2000 |
3 pages |
| Authors:
Leon O. Chua; CALIFORNIA UNIV BERKELEY
|
| We have been pursuing the development of image and video fusion algorithms suitable for implementation on analog array hardwares, such as the CNN Universal Machine. We are attempting to develop source independent algorithms which produce a fused image which contains all the features from the source images which are relevant to a human observer. |
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| A Graphically Based Test Signal Generator |
SEP 2000 |
31 pages |
| Authors:
Timothy M. Hughes; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| A digital test signal generator has been developed in the Mathwork's MATLAB environment, to allow for evaluation of the Adjustable Bandwidth Concept Algorithm, U.S. patent #5,257,211. The signal generator incorporates a graphical user interface for the optional graphical placement of signals on the time- frequency signal display. Signal components include tones, binary phase shift keyed signals, band limited gaussian noise and additive white gaussian noise. ... |
|
| A Signal Energy Detection Implementation |
DEC 1999 |
30 pages |
| Authors:
Timothy M. Hughes; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| The Adjustable Bandwidth Concept (ABC) signal energy detector has been implemented in the Mathwork's MATLAB environment, with a graphical user interface. The ABC algorithm, U.S. patent #5,257,211 can be applied to a variety of digitized signals, including both audio and basebanded RF communications signals. The implementation allows for easy re-configuration of the algorithm through graphical parameter control, which facilitates signal energy detection tests. ... |
|
| Depthimeter |
13 SEP 1999 |
32 pages |
| Authors:
Brian S. Bourgeois; Michael M. Harris; Andrew B. Martinez; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The depthimeter comprises a heave sensor, a mean path compensator and a combiner. The mean path compensator comprises a ranging device which measures the instantaneous distance of the vehicle from a fixed point on the vehicle to ocean surface as a function of time; a range compensator to compensate for signal dropouts in the ranging devices data, for sensor offset angle, and vehicle pitch and roll, thereby providing a signal ... |
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| Method and Apparatus for Generating Modified Speech from Pitch-Synchronous Segmented Speech Waveforms |
03 AUG 1999 |
|
| Authors:
George S. Kang; Lawrence J. Fransen; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A system that synchronously segments a speech waveform using pitch period and a center of the pitch waveform. The pitch waveform center is determined by finding a local minimum of a centroid histogram waveform of the low-pass filtered speech waveform for one pitch period. The speech waveform can then be represented by one or more of such pitch waveforms or segments during speech compression, reconstruction or synthesis. The pitch waveform ... |
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| On the Application of the Parks-McClellan Algorithm to the Design of Quadrature Demodulation Filters |
JUN 1999 |
|
| Authors:
R. Inkol; D. P. Nguyen; DEFENCE RESEARCH ESTABLISHMENT OTTAWA (ONTARIO)
|
| New results are presented concerning the use of the Parks-McClellan algorithm to design filters for digital quadrature demodulators based on quadrature mixing and lowpass filtering concepts. The use of a 4:1 ratio between the sampling rate and intermediate frequency to reduce computational cost complicates this problem. Since the in-phase (I) and quadrature (Q) filters become odd and even length filters, respectively, the matching of the passband gains becomes an important ... |
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| Amplification of Signals from high Impedance Sources |
02 MAR 1999 |
|
| Authors:
Timothy B. Straw; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An analog signal conditioner for signals from high impedance sources adapted for ready implementation as an integrated circuit. The signal conditioner includes a preamplifier, a step gain amplifier and a low-pass filter. A calibration generator can inject a calibration signal into the system. The step gain amplifier includes analog switches that control paths through a voltage divider network to provide negative feedback on both sides of a fully differential operational ... |
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| The VLSI Implementation of a GIC Switched Capacitor Filter |
MAR 1998 |
153 pages |
| Authors:
Mickey Joe D. Wilbur; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In this research, the design and VLSI implementation of a digitally programmable active analog filter, based on the Generalized Immittance Converter (GIC) circuit, are presented. The programmable features include the filter type (bandpass, high pass, low pass or notch), the center or cut off frequency, and the quality factor. Switched capacitor networks are used to implement resistances. The design was first simulated and then implemented on a wire wrap board ... |
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| Analyses of Near-Field and Near-Regional Signals from the Black Thunder Mine |
FEB 1998 |
52 pages |
| Authors:
Terrance G. Barker; Keith L. McLaughlin; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
|
| In this report we present analyses of seismic data recorded at the Black Thunder coal strip mine in the Powder River Basin of Wyoming. The data (collected by Stump et al, 1996) are a set of recordings at distances of a few kilometers from mining activity at that mine. Our objective was to determine whether these near-field data revealed features of quarry blasting that were ... |
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| Applications of On-Chip Samplers for Test and Measurement of Integrated Circuits |
1998 |
2 pages |
| Authors:
Ron Ho; Bharadwaj Amrutur; Ken Mai; Bennett Wilburn; Toshihiko Mori; Mark Horowitz; STANFORD UNIV CA CENTER FOR INTEGRATEDSYSTEMS
|
| Displaying the real-time behavior of critical signals on VLSI chips is difficult and can require expensive test equipment. The authors present a simple sampling technique to display the analog waveforms of high bandwidth on- chip signals on a laboratory oscilloscope. It is based on the subsampling of periodic signals as proposed in "Measuring High-bandwidth Signals in CMOS circuits (Electronics Letters, v29 n20, p1761-1762, Sep 1993). This circuit was used to ... |
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| Radiation Transport Effects and the Interpretation of Infrared Images of Gravity Waves and Turbulence |
1998 |
15 pages |
| Authors:
John Gruninger; James W. Duff; James H. Brown; William A. Blumberg; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Radiation transport modulates the spatial frequencies of atmospheric structures, acting as a low pass filter, which causes the power spectra of the accumulated radiance to have different power spectral slopes than the underlying atmospheric structure. Additional effects arise because of the non-stationarity of the atmosphere. The SHARC atmospheric radiance code is used to model both equilibrium and non-equilibrium radiance and radiance fluctuation statistics. It predicts two dimensional radiance spatial covariance ... |
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| Ultra-Broadband Hydrophone |
02 DEC 1997 |
|
| Authors:
Roger L. Woodall; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The present invention relates to an ultra broadband hydrophone which has two major electronic components and one mechanical component. The first electronic component comprises a flux gate magnetometer for sensing changes in an ambient magnetic field and for creating an electrical signal representative of the ambient magnetic field. The second electronic component comprises an electrical circuit for demodulating the electrical signal and a low pass filter for smoothing the demodulated ... |
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| CNN Universal Chip |
31 OCT 97 |
7 pages |
| Authors:
J. Bokor; Leon Chua; CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB
|
| The goal of designing and building a high performance CNN Universal Machine integrated circuit with demonstrable image processing capabilities was achieved during the contract funding period. The design of the CNN Universal Chip architecture was conducted under the guidance of theoretical results explicating the robust elemental processing capabilities of such cellular analog hardwares, which were developed under this contract. Furthermore, the analogic algorithms needed for implementing the specific image processing ... |
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| Method for Data Gap Compensation |
07 OCT 1997 |
|
| Authors:
Francis J. O'Brien Jr.; Chung T. Nguyen; Sherry E. Hammel; Bruce J. Bates; Steven C. Nardone; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The present invention comprises a method for filling in missing data intervals in a quantized time-dependent data signal that is generated by, e.g., an underwater acoustic sensing device. In accordance with one embodiment of the invention, this quantized time-dependent data signal is analyzed to determine the number and location of any intervals of missing data, i.e., gaps in the time series data signal caused by noise in the sensing equipment ... |
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| Differential Preamplifier and Pre-Emphasis Network. |
29 APR 1997 |
|
| Authors:
James D. Hagerty; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A preamplifier and pre-emphasis network is provided having a differential amplifier exhibiting common mode noise rejection. The preamplifier is particularly suited for use with a double-sided sensor element and it includes a double-sided, balanced calibration circuit. First and second variable gain buffers are joined to the differential amplifier for preventing current noise degradation at the differential amplifier inputs. A pre-emphasis network is further provided in conjunction with the variable gain ... |
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| A Direct-Sequence-Code Division Multiple Access/Differential Phase-Shift Keying (DS-CDMA/DPSK) Modem Design |
MAR 97 |
|
| Authors:
Onder Kara; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The development of a differential phase-shift keying (DPSK), direct sequence, spread spectrum modem is conducted for the purpose of creating a prototype design to be implemented in a multi-user environment. In this design, a maximal length sequence of 31 chips is used to spread the information data. The multi-user performance analysis is performed by using Bit Error Rate (BER) test equipment (1645 Hewlett Packard data error analyzer). A multi-user interference ... |
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| Feasibility of Implementing Near-Field Acoustic Holography at Large Scale |
MAR 97 |
47 pages |
| Authors:
Gerard P. Carroll; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SHIP HYDROMECHANICS D EPT
|
| This report presents the results of a numerical investigation into the technical feasibility of implementing near-field acoustic holography (NAH) at large scale using the Intermediate Scale Measurement System (ISMS) . Results are presented using two data sets, one corresponding to numerically generated hologram plane pressures for the Whitefish model and the other to actual experimental data for the Naval Research Laboratory (NRL) C-50 model. The numerically generated hologram plane pressures ... |
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| Method and Apparatus for Spectrum Analysis by Complex Cumulants. |
11 FEB 1997 |
|
| Authors:
David J. Edelblute; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A method for spectrum analysis by complex cumulants comprises the steps of receiving a signal, Fourier transforming the signal to form a series of complex Fourier coefficients, forming complex cumulants from the series of complex Fourier coefficients, and displaying the cumulants in a form wherein the non-Gaussian components of the signal are emphasized. |
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| In-Situ Testing of Radiation Effects on VLSI Capacitors Using the NPS linear Accelerator |
DEC 96 |
109 pages |
| Authors:
Duane Salsbury; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The study of radiation effects on VLSI components is a very heavily researched topic. There are several reasons for this research, one of which is the application of VLSI components to space related vehicles. One component essential to Analog VLSI elements is the capacitor. The purpose of this paper is to better define the actual effects of radiation on the MOS VLSI capacitor. The radiation testing is conducted using the ... |
|
| Experimental and Theoretical Aspects of Corrosion Detection and Prevention |
31 OCT 96 |
83 pages |
| Authors:
W. R. Madych; O. F. Devereux; CONNECTICUT UNIV STORRS DEPT OF MATHEMATICS
|
| This report summarizes activities and work completed between September 1, 1993 and October 31, 1996. In addition to this summary it contains two parts consisting of various details. The experimental portion of this project is supervised by 0. F. Devereux and conducted by P. C. Su. It is devoted to the investigation of initiation and growth kinetics of corrosion in airframe alloys, including joined and protectively coated specimens. The goal ... |
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| TWO APPROACHES TO HIGH-FIDELITY, PHYSICS-BASED MODELING: SSGM & E2DIS, |
OCT 1996 |
|
| Authors:
BRUCE WILCOXEN; HARRY HECKATHORN; NAVAL RESEARCH LAB WASHINGTON DC
|
| (U) THIS PAPER DISCUSSES TWO NRL EFFORTS DESIGNED TO IMPROVE THE FIDELITY AND HEIGHTEN THE CONFIDENCE IN TWO CLASSES OF SIMULATIONS. FIRST ARE THOSE BEING DONE IN SUPPORT OF THE BALLISTIC MISSILE DEFENSE ORGANIZATION (BMDO) THAT ARE PRIMARILY USED FOR THE TRADITIONAL PURPOSE OF SYSTEM ENGINEERING, OPERATIONAL TEST, AND EVALUATION. SECOND ARE THOSE BEING PURSUED FOR THE DEFENSE MODELING AND SIMULATION OFFICE (DMSO) THAT INVOLVE DISTRIBUTED INTERACTIVE SIMULATIONS, USED PRIMARILY ... |
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| PASSIVE EXPLOITATION OF THE ELECTRO-MAGNETIC ENVIRONMENT FOR IMPROVED TARGET TRACKING, SITUATION ASSESSMENT AND THREAT REFINEMENT, |
SEP 1996 |
|
| Authors:
DAVID L. HALL; Robert F. Ogrodnik; PENNSYLVANIA STATE UNIV STATE COLLEGE
|
| (U) THIS PAPER ADDRESSES THE CAPABILITIES AND PERFORMANCE OF A NONINTRUSIVE, PASSIVE SURVEILLANCE AND IMAGING SENSOR TECHNOLOGY WHICH HAS BEEN APPLIED TO THE DETECTION AND TRACKING OF COVERT, SMALL SIGNAL TARGETS. THE FUSION MODEL IS USED AS A CONTEXTUAL BASIS TO EXPLAIN THE SEQUENCE AND STRUCTURE OF SUPPORT OF THE SYNTHESIS OF A BROAD AREA SURVEILLANCE ARCHITECTURE WHICH DRAWS FROM MULTIFREQUENCY FUSION BASED TECHNOLOGIES AND CAN CREATE A POWERFUL YET ... |
|
| Underwater Imaging with Acoustic Lenses: Image Processing and Visualization |
30 AUG 96 |
29 pages |
| Authors:
Behzad Kamgar-Parsi; NAVAL RESEARCH LAB WASHINGTON DC ADVANCED INFORMATION TECHNOLOGY BRANCH
|
| This report discusses image processing, scene reconstruction, and visualization techniques used for underwater acoustic images taken with lens- based systems from a stationary platform. These systems are designed for high- resolution imaging of objects from distances of a few meters. The acoustic lenses used for beamforming in the imaging systems are made of crystal polystyrene and are cut in cylindrical or spherical shapes. The cylindrical lens has a fan-shaped beam ... |
|
| Method for Data Gap Compensation. |
28 JUN 1996 |
30 pages |
| Authors:
Francis J. O'Brien; Chung E. Nguyen; Sherry E. Hammel; Bruce Bates; Steven C. Naroone; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The present invention comprises a method for filling in missing data intervals in a quantized time-dependent data signal that is generated by, e.g., an underwater acoustic sensing device. In accordance with one embodiment of the invention, this quantized time dependent data signal is analyzed to determine the number and location of any intervals of missing data, i.e., gaps in the time series data signal caused by noise in the sensing ... |
|
| Triaxial Magnetic Heading Sensing Apparatus Having Magnetaresistors and Nulling Coils. |
21 MAY 1996 |
|
| Authors:
Steven J. Koerner; Anthony E. Lifur; Michael J. Wall; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A triaxial magnetic heading sensing apparatus includes nulling coils and magnetoresistive sensors having inputs and outputs. The nulling coils are arranged in parallel relation to three orthogonal planes intersecting at a common center point. The sensors are disposed along orthogonal axes in parallel relation to the orthogonal planes and in close proximity to the center point. Each sensor has a bridge configuration balanced in the absence of an applied external ... |
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| Image Reconstruction From Strongly Scattering Penetrable Objects Using a Differential Cepstral Filter |
MAY 1996 |
118 pages |
| Authors:
John B. Morris; ROME LAB HANSCOM AFB MA
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| Conventional algorithms for media characterization in diffraction tomography rely on weakly scattering approximations such as the Born or Rytov methods. In this report, we investigate the utility of a nonlinear filtering procedure applied to single-view backpropagated images of strongly scattering two-dimensional objects. With a single illumination direction and constant wave number k0, exact scattered far fields are backpropagated to form an image of the scattering potential times the total field. ... |
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LOW PASS FILTERS
