Parallel-line beamsteering for enhanced anomaly detection

Parallel-line beamsteering, a new seismic processing method, was developed to enhance signal from laterally continuous heterogeneities (e.g. tunnel, mine shaft, etc.) and attenuate scatter from localized non-laterally contiguous heterogeneities (e.g. clay lens, boulder, etc.). This method takes advantage of the linear cross line nature of potential targets. Parallel-line beamsteering applies spatial shifting and vertical stacking to parallel-line seismic data in combination with backscatter analysis of surface waves (BASW) and diffraction imaging processing. A processing flow that optimizes the stack and shift process was empirically determined using the standard BASW and diffraction imaging processing flows. This empirically established processing flow was evaluated on parallel-line data acquired at a tunnel test site at the Yuma Proving Grounds in southwestern Arizona. Results show that this method enhances signal from the tunnel by as much 2.8 dB and attenuates other scatter events by as much as 3.9 dB. Beamsteering analysis also reduced the number of possible tunnel locations interpreted from diffraction imaging results using standard interpretation based on spatial matching criteria by up to 66% and from the BASW imaging results by up to 50%. Interpreting results of parallel-line beamsteering requires a less skilled interpretation than conventional tunnel detection methods. This method can also be used to determine the orientation of a tunnel with respect to the two seismic lines. Additionally, this method maintains the small acquisition footprint of current 2D seismic methods required for tunnel detection applications

Analysis of spatial resolution in phase-sensitive compression optical coherence elastography

Funding: Australian Research Council; the Cancer Council Western Australia; OncoRes Medical; William and Marlene Schrader Trust of the University of Western Australia scholarship.Optical coherence elastography (OCE) is emerging as a method to image the mechanical properties of tissue on the microscale. However, the spatial resolution, a main advantage of OCE, has not been investigated and is not trivial to evaluate. To address this, we present a framework to analyze resolution in phase-sensitive compression OCE that incorporates the three main determinants of resolution: mechanical deformation of the sample, detection of this deformation using optical coherence tomography (OCT), and signal processing to estimate local axial strain. We demonstrate for the first time, through close correspondence between experiment and simulation of structured phantoms, that resolution in compression OCE is both spatially varying and sample dependent, which we link to the discrepancies between the model of elasticity and the mechanical deformation of the sample. We demonstrate that resolution is dependent on factors such as feature size and mechanical contrast. We believe that the analysis of image formation provided by our framework can expedite the development of compression OCE.Publisher PDFPeer reviewe

TERSSE: Definition of the Total Earth Resources System for the Shuttle Era. Volume 2: An Assessment of the Current State-of-the-Art

Results of a state-of-the-art assessment of technology areas which affect the Earth Resources Program are presented along with a functional description of the basic earth resources system. Major areas discussed include: spacecraft flight hardware, remote sensors, data processing techniques and hardware, user models, user interfaces, and operations technology

NASA Oceanic Processes Program annual review

Current flight projects and definition studies, descriptions of individual research activities, and a bibliography of referred journal articles appearing within the past two years are contained

Abstracts for the International Conference on Asteroids, Comets, Meteors 1991

Topics addressed include: chemical abundances; asteroidal belt evolution; sources of meteors and meteorites; cometary spectroscopy; gas diffusion; mathematical models; cometary nuclei; cratering records; imaging techniques; cometary composition; asteroid classification; radio telescopes and spectroscopy; magnetic fields; cosmogony; IUE observations; orbital distribution of asteroids, comets, and meteors; solar wind effects; computerized simulation; infrared remote sensing; optical properties; and orbital evolution

Global Observations and Understanding of the General Circulation of the Oceans

The workshop was organized to: (1) assess the ability to obtain ocean data on a global scale that could profoundly change our understanding of the circulation; (2) identify the primary and secondary elements needed to conduct a World Ocean Circulation Experiment (WOCE); (3) if the ability is achievable, to determine what the U.S. role in such an experiment should be; and (4) outline the steps necessary to assure that an appropriate program is conducted. The consensus of the workshop was that a World Ocean Circulation Experiment appears feasible, worthwhile, and timely. Participants did agree that such a program should have the overall goal of understanding the general circulation of the global ocean well enough to be able to predict ocean response and feedback to long-term changes in the atmosphere. The overall goal, specific objectives, and recommendations for next steps in planning such an experiment are included

Inappropriate development, engineering ideology and the corporatist vision in Italy, 1890-1929

The thesis was conceived as an effort to contribute to three more or less distinct academic discourses, by attempting to analyze the relationship between them. These fields of study are: 1) technology as social and political process, and the related category of scientific management as ideology in industrial capitalism; 2) the corporatist conception of political organization; 3) the contemporary debate on appropriate development and alternative technology for today's poor countries. The historical phenomenon invoked as the mediating element in trying to unite these categories is corporatist reformism in inter-war Italy. The bulk of the thesis is an attempt to examine this reformism as it was expressed by the engineering community. It is argued that the generic tensions in industrial capitalism between technological rationality in the organization of production and the opposing fragmentary pressures applied by economic competition - tensions which emerged in the social philosophy of technocracy - were atao present in the articulation of corporatist ideology in Italy. The historical feature of Italian development which gave the political push to the engineering ideology was, it is suggested, the legacy of dependent and inappropriate industrial development. Thus economic weakness because of an unsuccessful development model which conformed little to factor endourent - the 19th century British model - encouraged social reformism to be conceived in terms of technological solutions. The resulting reform conception - technocratic corporatism - was however merely ideology, and as such emerged to conceal failed practice. Apart from investigating the engineers' conception of reform, therefore, the thesis also traces the failures to implement reform at a technical level, which the success of the corporatist model presupposed