Miracle-dz/UniFAR-FTUs huggingface dataset:
Structure detection and statistical adaptive speckle filtering in SAR images

Abstract Current speckle filters attempt to restore the radar reflectivity using only the multiplicative speckle noise assumption. The best known filters, namely the Frost, Lee or Kuan niters are adaptive filters based on the local statistics, computed in a fixed square window. In this way, the speckle is reduced as a function of the heterogeneity measured by the local coefficient of variation. When the radar reflectivity undergoes significant variations due to the presence of strong scatterers or structural features (edges or lines) in the processing window, such speckle filtering is less effective. In this paper it is shown that the filtering process can be controlled both by the coefficient of variation and by various geometrical ratio detectors. Through shape adaptive windowing, these detectors allow the use of large window sizes for better speckle reduction while preserving spatial resolution and structural features. The backscattered intensity is modelled as K-distributed within speckled targets and.
Analysis of Initiation of Sediment Suspension from Bed Load

A theoretical analysis of the initiation of sediment suspension is performed based on the concept of probability of suspension. The proposed condition for the initiation of sediment suspension from the top of the bed-load layer is comparable with most existing empirical relationships for large particle Reynolds numbers. The study shows that a constant Rouse parameter can be used as the critical condition for sediment suspension only for large dimensionless particle diameters. When the probability of suspension is taken to be an infinitesimal value (\iP=10\u-\u7), the derived relationship of the Shields parameter and the particle Reynolds number is in good agreement with the updated Shields diagram.
3D Kirchhoff prestack time migration in average illumination-azimuth and incident-angle domain for isotropic and vertical transversely isotropic media

Conventional offset domain prestack migration tends to bring ambiguity and migration artifacts because it smears energy from different angles at the image point. To avoid this, prestack depth migration implementations in angle domain have been investigated in the past decades. As an efficient imaging tool, angle domain Kirchhoff prestack time migration is still useful and was proposed recently. However, existing algorithms cannot handle ray bending and anisotropy correctly. Practically, azimuth analysis for fractured reservoirs should be carried out after migration for most geological settings. Unfortunately, the existing migration algorithm implicitly involves some kind of binning to source-receiver azimuth, which may not be the real wave-path azimuth, especially for side-scattering or out-of-plane waves. In this paper, we present an algorithm for 3D Kirchhoff prestack time migration in average illumination azimuth and incident angle domain, which matches true wave path naturally and more accurately. To handle ray bending and vertical transversely isotropy, we propose several approaches to estimate two-way traveltime and the corresponding angular attributes through extended offset-to-angle mapping. Based upon these approaches, our 3D prestack time migration can provide high-quality common-image gathers for amplitude variation with incident angle and/or amplitude variation with offset and azimuth analyses, even in media with slight to moderate lateral heterogeneity. The 2D and 3D synthetic examples prove the validity of our methods.
Ecological genetic connectivity between and within southeast African marginal coral reefs.

Marine protected areas (MPAs) have been established along the East African coast to protect coral communities from human and natural disturbance. Their success is dependent on the degree to which resource populations are self-seeding or otherwise connected. Estimates of contemporary gene flow on or between south-east African reefs are thus required to reveal the interdependence of the South African coral communities and those to the north. Accordingly, the ecologically relevant (1 or 2 generations) connectivity of two broadcast-spawning corals, Acropora austera and Platygyra daedalea, was assessed on reefs in the region, from the Chagos Archipelago to Bazaruto Island in Mozambique and Sodwana Bay in South Africa, using hyper-variable genetic markers. Analysis of genetic diversity and differentiation provided evidence for the existence of four discrete genetic populations of A. austera and five of P. daedalea in the sampled area. Higher genetic diversity was found on northern South African reefs (Nine-mile Reef and Rabbit Rock) and migration patterns inferred from assignment tests suggested that, at ecological time scales, South African reefs are disconnected from those in Mozambique and might originate from a source of gene flow that was not sampled. The analysis of fine-scale genetic connectivity conducted on Twomile Reef (TMR) demonstrated the existence of significant spatial genetic structure at the reefal scale that might be related to the non-random dispersal of coral larvae, putatively explaining the genetic discontinuity observed in the region. Altogether, the results are consistent with the isolation observed in other studies using less variable markers, and support the hypothesis that there is demographic discontinuity between the coral populations along the south-east African coast. More importantly, Acropora austera and P. daedalea represent different life strategies in the South African reef communities yet manifested similar genetic patterns, suggesting that these corals are responding similarly to forces that are driving genetic connectivity in the region. For management purposes, the genetically distinct populations identified at each of the spatial scales analysed in this study may correspond to management units, or evolutionarily significant units. Furthermore, since some reefs appear to act as “landing-sites” for migrants (Nine-mile Reef) and there is evidence of significant within-reef genetic structure (TMR), an adaptive management framework would be the best option for the MPA in the region.
Error analysis of corner and center points for image registration

Image registration is an active research topic in the fields of remote sensing, photogrammetry, computer vision, pattern recognition, and medical image processing. Both corner and geometric center points are used for image registration, but not much attention has been paid to date to the differences in the outcome of image registration when these different types of points are used. Such differences have the potential to directly affect the success of multiresolution or multimodal image registration. The goal of this paper is to compare the characteristics of corner and center points in image registration and to quantify the differences in the registration accuracy when different features are used. Corners and geometric centers were compared in two cases: registration of images with the same resolution and registration of images with different resolutions. The results show that geometric centers provide more accurate results for image registration in both cases. Quantitative analysis revealed that the position error of the centers is only about 47%–63% of the position error of the corners. Experiments confirmed this finding.
Instability of Baroclinic Tidal Flow in a Stratified Fjord

Abstract The Taylor–Goldstein equation is used to investigate the stability of a baroclinic tidal flow observed in a stratified fjord. The flow is analyzed at hourly intervals when turbulent dissipation measurements were made. The critical gradient Richardson number is often close to the Miles–Howard limit of 0.25, but sometimes it is substantially less. Although during 8 of the 24 periods examined the flow is marginally stable, it is either very stable or very unstable in others. For the unstable flow, the e-folding period of the fastest growing disturbances is 83–455 s, about 46% of the buoyancy period at the levels where the fastest growing disturbances have their maximum amplitude. These disturbances to the flows have wavelengths about 20%–72% of the water depth and have mostly a second-mode structure. Simultaneous measurements of the flow and turbulence allow for testing of the hypothesis that the growth rates of the most unstable disturbances are related to the turbulent dissipation rates. Dissipati.
Diurnal and Seasonal Variations of Strato-Mesospheric Ozone.

The J= 6 1,5 -6 0,6 (110.836 GHz) line of strato-mesopheric ozone has been measured employing a millimeterwave ozone sensor equipped with an SIS mixer receiver. The receiver noise of the SIS mixer is 34 K (SSB), and the spectrometer covers 70 MHz with a frequency resolution of 35 kHz at the present. From these observations, diurnal and seasonal variations of mixing ratio of day and night, and the day/ night ratio of mixing ratio are discussed.
SPATIAL AND STRATIGRAPHIC VARIATION OF MARINE PALEOENVIRONMENTS IN THE MIDDLE-UPPER MIOCENE GATUN FORMATION, ISTHMUS OF PANAMA

ABSTRACT The middle–upper Miocene (Serravallian-Tortonian) Gatun Formation of Panama is one of the most diverse marine fossil assemblages in the Caribbean, and has been widely used as a baseline in studies investigating the effects of the late Neogene closure of the Central American Seaway. Despite being the focus of exhaustive paleoecological sampling studies, previous studies have not revealed the fine-scale spatial and temporal variation in the composition of the Gatun fauna. High-resoluton faunal inventories were conducted from over 600 stratigraphic horizons in the Gatun Formation, capturing more than 200 species, which represent mostly widespread or common, and typically macroscopic taxa. Cluster and detrended correspondence analyses (DCA) reveal a stratigraphic pattern of variation in the faunal composition of individual horizons as well as differences between sampling sites. Stratigraphic curves of DCA axis scores indicate relative shifts in water depth and sedimentation through the stratigraphy and among localities. Overall the Gatun reveals both coarse- and fine-scale temporal variations in paleobathymetry, reflecting long-term shifts in basin subsidence and accommodation space that is potentially overprinted by fifth- or sixth-order glacio-eustatic cycles. The formation accumulated during an overall phase of increasing accommodation space, with major intervals of transgression (lower Gatun), regression (middle Gatun), and further transgression to mid-shelf depths (upper Gatun). Shallowing through the middle part of the Gatun is largely the result of an increase in supply of pyroclastic and volcaniclastic sediments from the adjacent volcanic arc. These findings have implications for understanding the tectonic evolution of the Canal Basin.
Fossil spring deposits in the southern Great Basin and their implications for changes in water-table levels near Yucca Mountain, Nevada, during Quaternary time

Fossil spring deposits are common in the southern Great Basin, and their distribution provides important constraints on the hydrologic response of the regional water table to climate change. This information is crucial, because the proposed high-level nuclear waste repository at Yucca Mountain will be located ∼200–400 m above the modern water table. Water tables will rise in response to a future return to glacial climates, but the magnitude of the change—and the consequences for radionuclide travel times and overall repository integrity—are key uncertainties. Increased recharge during past pluvial periods in the Spring Mountains and Sheep Range caused water tables to rise and ground water to discharge over broad expanses of the Las Vegas Valley system, and in nearby Pahrump, Sandy, and Coyote Springs Valleys. In contrast, other valleys in the region contain only small areas of Pleistocene discharge resulting from local damming of ground water by faults that cut valley alluvium. In these instances, which include the Valley Wells area, and Piute and northern Coyote Springs Valleys, smaller ranges such as the Clark and New York Mountains supplied the moisture. The change in water-table levels since the last full glacial period varies between and within valleys, from as little as 10 m in several areas to 95 m in the Coyote Springs Valley. At Yucca Mountain, the water table has probably changed by ≤115 m in response to climate change. The spring deposits and the mollusk faunas found with them, often misinterpreted as lacustrine in origin, share many essential features with active spring systems in northeast Nevada. Deposits associated with discharge mainly consist of pale brown silt and sand that is entrapped by dense stands of phreatophytes covering valley bottoms when water tables are high. Pale green mud, containing a mix of aquatic, semiaquatic, and moist terrestrial mollusks, accumulates in wet meadows and marshes associated directly with spring discharge. The record in subbasins of the Las Vegas Valley system is dominated by late Wisconsin–age sediments, although pond sediments and alluvium belonging to at least one older (pre-Wisconsin? ) pluvial period are also locally exposed. Deposits from two even earlier episodes of spring discharge, both of which also occurred during Rancholabrean time (10 to <450 ka), are exposed in the Pahrump, Chicago, Piute, and Coyote Springs Valleys, and in the Valley Wells. The records from the Pahrump and Coyote Springs Valleys are especially well exposed and likely extend back to at least early Pleistocene time.
Heterogeneities in D” beneath the southwestern Pacific inferred from scattered and reflected P‐waves

We investigate the fine structure of the D” layer beneath the southwestern Pacific using short‐period data from 7 deep events in the Fiji‐Tonga region recorded at the J‐Array in Japan. We use a double array migration method which integrates source array beamforming with receiver array beamforming. The phase‐weighted stacking technique, which reduces incoherent noise by employing complex trace analysis, is also applied. This combination greatly enhances small phases common to the source and receiver beams. We present coherent phases originating from the lowermost mantle using these new array techniques. The results indicate that seismic energy is reflected at two negative discontinuities near 2550 and 2650 km. The migration shows only weak evidence for scattering objects which may be an indication that scattering in the D” layer beneath the southwestern Pacific is weak.
Application of AquaCrop model in deficit irrigation management of cabbages in Keiyo Highlands

Crop growth can be simulated under different water application using simulation models. The main purpose of deficit irrigation is high water productivity with less application of water to plants. In this research, the potential of AquaCrop to simulate the growth of cabbages in Keiyo Highlands (0°22’45’’N and 35°32’9”, 2586 m.a.s.l) under nine different irrigation treatments in the dry season between December to February was studied. Statistical comparisons of observed and simulated biomass showed that R2 = 0.96, Root mean square error (RMSE) = 0.38 tons and coefficient of residuals = -0.17. The results showed that the model overestimated the biomass of cabbages. The model also provided excellent simulation of canopy and yield. In this study water productivity of 17 g/cm2 and Harvest index of 76% were found for cabbages. Key words: Deficit irrigation, AquaCrop, cabbage ‘Riana’ and water productivity.
Horizontal Mergers: An Equilibrium Analysis

The authors analyze horizontal mergers in Cournot oligopoly. They find general conditions under which such mergers raise price, and show that any merger not creating synergies raises price. The authors develop a procedure for analyzing the effect of a merger on rivals and consumers and, thus, provide sufficient conditions for profitable mergers to raise welfare. They show that traditional merger analysis can be misleading in its use of the Herfindahl Index. Their analysis stresses the output responses of large firms not participating in the merger. Copyright 1990 by American Economic Association.
Mapping the irrigated rice cropping patterns of the Mekong delta, Vietnam, through hyper-temporal SPOT NDVI image analysis

Successful identification and mapping of different cropping patterns under cloudy conditions of a specific crop through remote sensing provides important baseline information for planning and monitoring. In Vietnam, this information is either missing or unavailable; several ongoing projects studying options with radar to avoid earth observation problems caused by the prevailing cloudy conditions have to date produced only partial successes. In this research, optical hyper-temporal Satellite Pour l'Observation de la Terre (SPOT) VEGETATION (SPOT VGT) data (1998–2008) were used to describe and map variability in irrigated rice cropping patterns of the Mekong delta. Divergence statistics were used to evaluate signature separabilities of normalized difference vegetation index (NDVI) classes generated from the iterative self-organizing data analysis technique algorithm (ISODATA) classification of 10-day SPOT NDVI image series. Based on this evaluation, a map with 77 classes was selected. Out of these 77 mapped classes, 26 classes with prior knowledge that they represent rice were selected to design the sampling scheme for fieldwork and for crop calendar characterization. Using the collected information of 112 farmers’ fields belonging to the 26 selected classes, the map produced provides highly accurate information on rice cropping patterns (94% overall accuracy, 0.93 Kappa coefficient). We found that the spatial distributions of the triple and the double rice cropping systems are highly related to the flooding regime from the Hau and Tien rivers. Areas that are highly vulnerable to flooding in the upper part and those that are saline in the north-western part of the delta mostly have a double rice cropping system, whilst areas in the central and the south-eastern parts mostly have a triple rice cropping system. In turn, the duration of flooding is highly correlated with the decision by farmers to cultivate shorter or longer duration rice varieties. The overall spatial variability mostly coincides with administrative units, indicating that crop pattern choices and water control measures are locally synchronized. Water supply risks, soil acidity and salinity constraints and the anticipated highly fluctuating rice market prices all strongly influence specific farmers’ choices of rice varieties. These choices vary considerably annually, and therefore grown rice varieties are difficult to map. Our study demonstrates the high potential of optical hyper-temporal images, taken on a daily basis, to differentiate and map a high variety of irrigated rice cropping patterns and crop calendars at a high level of accuracy in spite of cloudy conditions.
Space-assisted irrigation management: an operational perspective

Irrigation Advisory Services (IAS) are the natural management instruments to achieve a better efficiency in the use of water for irrigation. IAS help farmers to apply water according to the actual crop water requirements and thus, to optimize production and cost-effectiveness. The project DEMETER (DEMonstration of Earth observation TEchnologies in Routine irrigation advisory services) aims at assessing and demonstrating how the performance and cost-effectiveness of IAS is substantially improved by the incorporation of Earth observation (EO) techniques and Information Society Technology (IT) into their day-to-day operations. EO allows for efficiently monitoring crop water requirements of each field in extended areas. The incorporation of IT in the generation and distribution of information makes that information easily available to IAS and to its associated farmers (the end-users) in a personalized way. This paper describes the methodology and selected results.
Ecohydrological effects of management on subalpine grasslands: From local to catchment scale

Grassland and pastures are important land uses in subalpine and alpine environments. They are typically subjected to management practices that can change the biophysical structure of the canopy through defoliation and can alter soil hydraulic properties. These modifications have the potential to impact hydrological and energy fluxes as well as the primary productivity of grasslands. We investigate how a series of management practices, such as grass cut, grazing, and the consequent soil compaction due to treading by animals are affecting water resources, flood generation, and grassland productivity in a subalpine region. Results are obtained using a mechanistic ecohydrological model, Tethys‐Chloris. The model is first confirmed using energy, water, and carbon fluxes measured at three eddy covariance stations over grasslands in Switzerland and discharge measured in a small experimental catchment. A series of virtual experiments are then designed to elucidate the importance of various management scenarios at the plot and catchment scales. Results show that only severe management actions such as low grass cuts or heavy grazing are able to influence considerably the long‐term hydrological behavior. Moderate management practices are typically unable to modify the system response in terms of energy and water fluxes. An important short‐term effect is represented by animal‐induced soil compaction that can reduce infiltration capacity leading to peak flow considerably higher than in undisturbed conditions. The productivity of vegetation in absence of nutrient limitation is considerably affected by the different management scenarios with tolerable disturbances that lead to higher aboveground net primary production.
Mexico City ozone concentrations as a function of readily-available meteorological parameters

Daily maximum ozone concentrations measured at four sites within the Mexico City basin during the winter months are plotted as functions of different meteorological parameters that are routinely measured at surface stations. We found that ozone concentrations are most strongly correlated to the increase in daytime temperature and the maximum daytime wind speed. We also discovered that high ozone values at the sites in the southern end of the basin occur when winds come out of the northeast. In contrast, wind direction was found to be uncorrelated with high ozone values at the northern sites. From straightforward combinations of the meteorological variables, we derived some simple rules for estimating lower and upper bounds on the ozone concentration. Scatter in the data was too long to give significance to best-fit equations and statistics. Additionally, a small rawinsonde data set was used to investigate ozone`s dependence on boundary-layer height and near-surface temperature gradient. Results were inconclusive, however, due to the small size of the data set.
Language and National Identity in Asia

Contents List of Maps Notes on Contributors 1. Language and National Identity in Asia: A Thematic Introduction PART I SOUTH ASIA 2. Bangladesh 3. India 4. Nepal and the Eastern Himalayas 5. Pakistan 6. Sri Lanka PART II EAST ASIA 7. China 8. Hong Kong 9. Japan 10. North and South Korea 11. Taiwan PART III SOUTHEAST ASIA 12. Burma/Myanmar 13. Cambodia 14. Indonesia 15. Malaysia 16. The Philippines 17. Singapore 18. Thailand and Laos 19. Vietnam References Index