196,298 research outputs found
Integration of frequency domain wideband antenna nulling and wavenumber domain image formation for multi-channel SAR
No full textA Multichannel Synthetic Aperture Radar (M-SAR) exploiting an antenna nulling based Electronic Counter-Counter Measures (ECCM) technique shall be able to cancel the effects of noise-like interferences over the collected SAR data. Since SAR systems often work with wide bandwidths to provide high resolution images, ECCM technique must account for the presence of wideband interference signal. In this paper we consider a wideband antenna nulling technique based on space-frequency adaptive nulling and we propose an integration of the WB antenna nulling scheme within the focusing algorithm for M-SAR systems, thus allowing a fusion between ECCM and usual SAR processing steps. The computational cost of the integrated algorithm is compared with the cost of more traditional sequence of the wideband extension of the Side-Lobe Canceller and the focusing operation, to show the computational feasibility of the proposed integrated algorithm. The possibility to perform suboptimally the space-frequency adaptive nulling is also considered
Intern experience at CH���M Hill, Inc.: an internship report
No full textIncludes author's vita"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical referencesA review of the author's internship experience with CH���M HILL, Inc.
during the period September 1975 through May 1976 is presented. During this nine month
internship the author worked as an Engineer II in the Industrial Processes discipline of this
large consulting engineering firm... The author's prime responsibility was as one of three
lead design engineers on the design of a large wastewater treatment facility for a pulp mill
in Hoquiam, Washington owned by ITT Rayonier Inc. The work generally consisted of the design
of individual treatment units and associated piping and pumping. The purpose of the project
was to provide wastewater treatment capabilities that would satisfy the effluent limitations
(standards) imposed upon the mill by the State of Washington Department of Ecology and the
U.S. Environmental Protection Agency. The author's assignment also entailed necessary
interaction with the project manager and other CH���M HILL design engineers and support staff
members, the client's representatives, and representatives of two other consulting engineering
firms working on the project. Thus, the internship position at CH���M HILL provided considerable
experience coordinating the author's work with the work of other engineers, guiding the design
and administrative efforts of a support staff, and interacting regularly with the client and
other consulting firms. This broad exposure to a variety of engineering and organizational
problems provided a valuable educational experience
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
Passive multistatic SAR with GNSS transmitters and using joint bi/multi-static CLEAN technique
No full textThis paper explores the capability of GNSS as opportunity transmitters for passive multistatic SAR. The large number of navigation satellites illuminating the same area from multiple view angles enables a single ground-based stationary receiver to combine the individual bistatic images thus achieving multistatic imagery capability with improved spatial resolution. Nevertheless, such a technique introduces artifacts corrupting the quality of the image information space. In this paper, a joint bi/multi-static CLEAN algorithm is exploited in order to correctly recovering the information of the scene. An experimental study is therefore presented, demonstrating the potential of this technology to extract detailed information of an area for persistent monitoring purposes
CLEAN technique for passive bistatic and multistatic SAR with GNSS transmitters
No full textThis paper presents the description and some examples of application of the CLEAN technique to passive SAR based on GNSS emissions, in order to extract the scattering centers in the achieved images and to increase the understanding of the imaged scene. Two different operative scenarios are considered: the bistatic case, involving a single GNSS transmitter and a ground-based receiver, and the multistatic case, achieved by considering the non-coherent combination of the BSAR images obtained by multiple, spatially separated satellites. The effectiveness of the technique in extracting the point scatterers' returns in the bi/multi-static images is proved against simulated and real datasets. Moreover, the inherent capability of rejection of the ghost scatterers arising in the multistatic images from close scattering centers is shown. The application of the proposed technique allows the proper extraction of the amount of information of the observed area. © 2015 IEEE
U.S. newspaper coverage of immigration in 2004: a content analysis
No full textThis study examined the U.S. newspaper coverage of immigration in 2004.
Previous studies have focused on the ideological implication of news coverage,
showing that the news frames conveyed elites?? racism toward immigrants. Little
research has been done to offer an overview of the general U.S. news content on
immigration in the 21st century, such as a study on how topics, themes, and sources
shape news frames. Guided by the principle of framing, this study explored the topics,
themes, sources, frames, and differences of three major U.S. newspapers??The New
York Times, the Los Angeles Times, and the Houston Chronicle??on immigration. One
hundred and twenty-nine articles were examined for this study. The study found that a
frame of ??confrontation and frustration?? emerged from the most dominant topics,
themes, and sources present in the newspapers. The study also showed that the
newspapers were less concerned about differentiating between ??who was legal and
who was illegal.?? Half of the time, the newspapers studied represented immigrants,
regardless of legal status, as one group. The newspapers were found to be more
concerned about reporting the immigrants?? shared experience of living in a non-native
country, including shared problems such as in home ownership and in education.
Differences among newspapers showed The New York Times?? ??unofficial newspaperof record?? reputation, the Houston Chronicle??s local emphasis, and the Los Angeles
Times?? reflection of minority power in California
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Integrated wideband antenna nulling and focusing technique for multi-channel Synthetic Aperture Radar
No full textThe imaging capability of a Synthetic Aperture Radar (SAR) could be seriously limited or denied by an electromagnetic noise-like interference signal impinging on the antenna during the synthetic aperture. A Multi-channel SAR (M-SAR), exploiting an antenna nulling based Electronic Counter-Counter Measures (ECCM) technique, shall be able to cancel the effects of interferences over the collected SAR data. Since SAR systems often work with wide bandwidths to provide high resolution images, the ECCM technique must account for the presence of WB interference signal. In this paper we consider a WB antenna nulling technique based on a space-frequency adaptive nulling and we propose an integration of the WB antenna nulling scheme within the focusing algorithm for MSAR systems, thus allowing a fusion between ECCM and usual SAR processing steps
M-regularity and the fourier-mukai transform
No full textThis is a survey of M-regularity and its applications, expanding on lectures given by the second author at the Seattle conference, in August 2005, and at the Luminy workshop "Geometrie Algebrique Complexe", in October 2005
Polarimetric detectors of extended targets for ship detection in SAR images
No full textThis paper deals with polarimetric detection of ships in SAR images of medium/high resolution (about meters). The aim is to develop detection techniques able to exploit the polarimetric information in order to improve the detection capability of ships or generally man-made targets modelled as extended targets (i.e. occupying multiple pixels). Both a decentralized and a centralized approach are considered for the fusion of the polarimetric information and their performance are characterized
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