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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Array analysis of radio frequency interference cancelation requirements for a land mine detection system /

Pratt, Devin Baker, January 2005 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2005. / Includes bibliographical references (p. 91-93).
12

Wingbeat modulation detection of honey bees using a continuous wave laser system

Scheppele, Ryan Hall. January 2006 (has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2006. / Typescript. Chairperson, Graduate Committee: Joseph A. Shaw. Includes bibliographical references (leaves 42-43).
13

Landmines on the table : a negotiations analysis of the global campaign to ban landmines /

Moody, Eric M. January 2008 (has links)
Thesis (Ph. D.)--University of Florida, 2008. / Vita. Includes bibliographical references (p. 361-380). Also available on the Internet.
14

Nonlinear acoustical detection of buried landmines using pulsed standoff excitation

Copenhaver, Benjamin Joseph 23 July 2014 (has links)
To help resolve certain practical issues with acoustical methods for landmine detection, experiments were performed using a pulsed, standoff source consisting of sixteen speakers mounted on a circular arc. This source, as well as a pair of 18-inch subwoofers, were used separately for acoustical excitation of the buried mine, and the response of the target site was examined as a function of source frequency, sound pressure level, and excitation signal type, with a particular focus on multitone signals. In addition, modeling was undertaken to investigate the effects of nonlinearity, including bimodular nonlinearity, on frequency generation. A numerical, time-domain solution based on a lumped-element model proposed by Donskoy et al. [J. Acoust. Soc. Am. 117, 690 (2005)] was developed and used to simulate pulsed excitation and the effects of bimodular nonlinearity, which allowed experimentally observed spectra to be compared with modeled results. / text
15

Broadband counter-wound helix antenna for land mine detection

Shivandas, Dilipkumar 03 1900 (has links)
Approved for public release, distribution is unlimited. / Ground penetrating radars (GPRs), also known as subsurface radars, are used in many applications including detection of land mines and unexploded ordnance (UXO). Despite significant long-term investment in GPRs for mine and UXO detection, it remains true that no GPR system that meets operational requirements has yet been fielded; however, recent advances in several mine detection radars under development have produced significant improvements in detection performance and false-alarm mitigation over what was achievable only a few years ago. This research examines the suitability of modeling helical antennas to achieve a broadband characteristic for GPR implementation. Although the two-arm counter-wound helix provides the required spot illumination, it is expected that more arms may have to be added to reduce the radiation in the back direction and to match the input impedance to the feed line. Microwave Design Studio (MDS) has been used extensively to simulate the broadband characteristics of the helical antenna. An overall design strategy is outlined, together with a more detailed treatment of the ground penetrating radar subsystems and topics that are relevant to effective subsurface radar operation. These include soil characterization, the choice of the frequency of operation, as well as the design and construction of suitable helical antennas. Finally, a new antenna structure called the counter-wound quadrifilar helical antenna (CQHA), which is suitable for subsurface radar applications, is examined. The counter-wound quadrifilar helical antenna has a broad bandwidth and a linear polarization with a controllable plane of polarization from a planar geometry. / Major, Republic of Singapore Air Force
16

Development of a 2-degree-of-freedom transverse line source for a seismo-acoustic SONAR

Wang, Shu-Kang. 12 1900 (has links)
This thesis describes the beach field-testing of a 2-degree-of-freedom (2-DOF) transverse line Rayleigh wave source for use in a seismo-acoustic SONAR for buried mine detection. The source is composed of six identical modules, each composed of two radial and two vertical inertial mass shakers, all mounted to a common base plate. The vertical and horizontal excitation of each module is independent. Electrically, the six modules are organized into three independent sets of two. The length of the source is 46 inches (1.17m), the width 6 inches (0.15m) and the weight 126 pounds (562N). Field tests were conducted using a 5-cycle, (smooth-)amplitude-modulated transient excitation signal. Based on past and present experience that the Rayleigh wave speed at the beach test site is approximately 90 m/s, a carrier frequency of 100 Hz was employed, producing a Rayleigh wavelength and surface penetration depth of approximately 1 m (approximately equal to the source aperture length), which is appropriate for the intended application. The source radiation directional characteristics were investigated for various relative amplitudes and phases of vertical and horizontal shaker excitation. A null result was obtained, that is, no unambiguous evidence of directivity was observed in any of the experiments conducted using this source. These included measurements wherein the source modules were removed from the common base plate and emplaced on the sand. The reason for this result is unknown, but it is suspected that a good possibility is that the beach sand medium just below its surface, whereupon the present source and receivers were deployed, is not homogeneous enough to support coherent spatial beamforming. Based upon the past success of a 4-element end-fire line array in producing directional Rayleigh wave radiation (10-15 dB front-to-back rejection), it is suggested that, if such a source can be made mobile, it may well be the best source candidate for a seismo-acoustic SONAR for buried mine detection.
17

Localization of Subsurface Targets using Optimal Maneuvers of Seismic Sensors

Alam, Mubashir 10 May 2006 (has links)
The use of seismic waves to detect subsurface targets such as landmines is a very promising technology compared to existing methods like Ground Penetrating Radar (GPR) and Electromagnetic Induction (EMI) sensing. The fact that seismic waves induce resonance in man-made targets, and hence more scattering, gives this method a natural ability to discriminate landmines from common types of clutter like rocks, wood, etc. Reflection and resonance from the targets can be used in imaging to detect the location of targets. However, existing methods require a large number of measurements for imaging and detection, which are expensive and time consuming. To reduce the number of measurements and enable faster detections, a new sensing strategy is proposed based on optimally maneuvering sensors. The system would operate in two main modes. In search mode, the goal would be to move on top of a target using the minimum number of measurements. Once the target is found, the system would switch to a detection mode to make its final decision. The seismic sensor system is an active system, where a seismic source generates the probing pulse. The waves reflected from buried targets are collected by an array of sensors placed on the surface, and then an imaging algorithm is used to estimate the target position. The performance bounds for this position estimate are derived in terms of the Fisher information matrix (FIM). This matrix gives the dependence of the target position estimate on the array position. Based on the FIM, the next optimal array position is determined by using the theory of optimal experiments. The next array position will be the one that reduces the uncertainty of the target position estimate the most. The whole array is moved to this new position, where the same steps are repeated. In this way, the target can be localized in a few iterations.
18

Characterization of nonlinearities in the propagation of high frequency seismic waves

Albert, Blace Chandler 05 1900 (has links)
No description available.
19

Correlation based landmine detection technique /

Mata, Raman Deep. January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 75-78). Also available on the Internet.
20

Correlation based landmine detection technique

Mata, Raman Deep. January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 75-78). Also available on the Internet.

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