The Sony NEX-VG30 video camera: A review for use in language documentation

National Foreign Language Resource Cente

Analysis using surface wave methods to detect shallow manmade tunnels

Multi-method seismic surface wave approach was used to locate and estimate the dimensions of shallow horizontally-oriented cylindrical voids or manmade tunnels. The primary analytical methods employed were Attenuation Analysis of Rayleigh Waves (AARW), Surface Wave Common Offset (SWCO), and Spiking Filter (SF). Surface wave data were acquired at six study sites using a towed 24-channel land streamer and elastic-band accelerated weight-drop seismic source. Each site was underlain by one tunnel, nominally 1 meter in diameter and depth. The acquired surface wave data were analyzed automatically. Then interpretations compared to the field measurements to ascertain the degree of accuracy. The purpose of this research is to analyze the field response of Rayleigh waves to the presence of shallow tunnels. The SF technique used the variation of seismic signal response along a geophone array to determine void presence in the subsurface. The AARW technique was expanded for practical application, as suggested by Nasseri (2006), in order to indirectly estimate void location using a Normalized Energy Distance (NED) parameter for vertical tunnel dimension measurements and normalized Cumulative Logarithmic Decrement (CALD) values for horizontal tunnel dimension measurements. Confidence in tunnel detects is presented as a measure of NED signal strength. Conversely, false positives are reduced by AARW through analysis of sub-array data. The development of such estimations is a promising tool for engineers that require quantitative measurements of manmade tunnels in the shallow subsurface --Abstract, page iii

The Application of Preconditioned Alternating Direction Method of Multipliers in Depth from Focal Stack

Post capture refocusing effect in smartphone cameras is achievable by using focal stacks. However, the accuracy of this effect is totally dependent on the combination of the depth layers in the stack. The accuracy of the extended depth of field effect in this application can be improved significantly by computing an accurate depth map which has been an open issue for decades. To tackle this issue, in this paper, a framework is proposed based on Preconditioned Alternating Direction Method of Multipliers (PADMM) for depth from the focal stack and synthetic defocus application. In addition to its ability to provide high structural accuracy and occlusion handling, the optimization function of the proposed method can, in fact, converge faster and better than state of the art methods. The evaluation has been done on 21 sets of focal stacks and the optimization function has been compared against 5 other methods. Preliminary results indicate that the proposed method has a better performance in terms of structural accuracy and optimization in comparison to the current state of the art methods.Comment: 15 pages, 8 figure

Direct and Indirect Effects of Flood Basalt Volcanism on Reservoir Quality Sandstone

This thesis describes the direct diagenetic effects on porous clean sand substrate due to the emplacement of basalt lava flows. The thesis also describes the effects of the emplacement of basaltic dykes and sills into clean porous sandstone. The primary dataset comes from the Cretaceous Etendeka Group, NW Namibia, where the Etendeka Flood Basalts (and associated subsurface plumbing system) interacted with the aeolian Twyfelfontein Formation sandstone. Secondary datasets from the recent Rekjanes Peninsular basalts, Iceland; the Miocene Columbia River Flood Basalt province and the Miocene Snake River Basalts, NW USA are used to constrain the direct effects of lava on substrates in a variety of palaeoenvironmental conditions. The thesis makes use of a number of analytical techniques including: petrography, scanning electron microscopy, image analysis, X-ray diffraction, X-Ray fluorescence, stable isotope spectroscopy (δ18 O and δ13 C) and gas permeability (Hasler and probe). The findings of this work constrain the degree of porosity reduction in clean sandstones due to intrusion emplacement over a complete range of thermal regimes, controlled by the magma flow pathways and duration. The effects range from mild hydrothermal activity and compaction through to intense pyrometamorphism, sediment melting and segregation. Beneath lava flows, the degree of porosity loss is determined by palaeoenvironment (specifically the availability of free water), the lava thickness and the substrate composition. Together the geometries of the igneous components (intrusions and extrusive flows) of the Etendeka Group compartmentalise the sedimentary components (Twyfelfontein Formation), which can be traced due to their effects on hydrothermal activity. The main compartment forming lithologies are vertical-subvertical intrusions, with the lava flows being a minor contributor. The diagenesis during hydrothermal activity was found to be a natural sequestration mechanism of CO2 derived from igneous activity as well as a highly compartmentalised porosity degradation mechanism

A comparison of three seismic methods in the arid environment

Eight locations in the vicinity of Las Vegas, Nevada, were noise tested using a shotgun, high frequency geophones, and an engineering seismograph. The noise spreads were examined for reflection events to determine shotpoint to geophone offset for an optimum window reflection profile. No reflection events were observed in the noise spreads. Trial optimum offset lines were run at location 1 and location 8. The resulting profiles contain spurious reflecting horizons that appear to be teal reflectors. At the eighth location, a delay time profile and a series of over-lapping refraction soundings were performed at the site of the optimum offset line. The delay time profile contains false structure that is an artifact of error accumulation in data reduction. The over-lapping refraction soundings produced a useful low resolution profile of an alluvial contact approximately five to ten feet deep; The surface geologic environment in the southwestern desert was found to be unfavorable to the optimum offset reflection profiling method and the delay time method. Both yield misleading results when applied to shallow targets in the desert southwest. The refraction sounding technique provided useful profiles and should continue to be used in the southwest for profiling shallow refraction targets

The Embrace of the Ocean - a case study in fulldome content-creation

"The Embrace of the Ocean" is a fulldome (planetarium) film directed and produced by Pekka Veikkolainen and Hannes Vartiainen. The film premiered at The Finnish Science Centre Heureka in March 2019. The film comprises of live footage shot with several different camera types and animated volumetric data visualization from various sources, rendered with custom in-house software. In this thesis I break down the reasoning and decisions made during the production of "The Embrace of the Ocean", from the point of view of the film director responsible for the post-production pipeline and final image quality. Namely, how to counteract cross-reflection all the way from the planning phases of the film, such as choices regarding filming equipment, to the final stages of the post-production: the compositing and color grading of the film. I show that the problem of cross-reflection exists at The Finnish Science Centre Heureka's planetarium through a series of measurements and propose several solutions from shot planning to compositing to minimize the effect through real-world examples implemented in the production of "The Embrace of the Ocean"

Rapid ecosystem-scale consequences of acute deoxygenation on a Caribbean coral reef

Loss of oxygen in the global ocean is accelerating due to climate change and eutrophication, but how acute deoxygenation events affect tropical marine ecosystems remains poorly understood. Here we integrate analyses of coral reef benthic communities with microbial community sequencing to show how a deoxygenation event rapidly altered benthic community composition and microbial assemblages in a shallow tropical reef ecosystem. Conditions associated with the event precipitated coral bleaching and mass mortality, causing a 50% loss of live coral and a shift in the benthic community that persisted a year later. Conversely, the unique taxonomic and functional profile of hypoxia-associated microbes rapidly reverted to a normoxic assemblage one month after the event. The decoupling of ecological trajectories among these major functional groups following an acute event emphasizes the need to incorporate deoxygenation as an emerging stressor into coral reef research and management plans to combat escalating threats to reef persistence