Miracle-dz/UniFAR-FTUs huggingface dataset:
4-D constrained depth conversion for reservoir compaction estimation Application to Ekofisk Field

Ekofisk Field (in the Norweigian sector of the North sea) is a remarkable example of a strongly compacted chalk reservoir. Since the start of production in 1971, the water bottom has subsided by over 8 m as a result of reservoir compaction (Hermansen et al.). The field-wide waterflood, begun in 1989, was expected to halt pressure depletion and reservoir compaction. After a few years of waterflooding, Ekofisk reservoir pressure began increasing, but compaction and subsidence continued. Laboratory studies on chalk cores indicated that high-porosity, oil-filled chalk compacts strongly when flushed with seawater. These studies, along with reservoir flow simulation and geomechanic modeling, led to a model of a water-weakening compaction (Sylte et al.). Ongoing efforts deployed to monitor the reservoir compaction and seabed subsidence include twice-a-year compaction logging in a monitoring well, daily GPS measurements at the platforms, and periodic bathymetry surveys (nine surveys from 1970 to 1999).
Patient Satisfaction in US Army Dental Treatment Facilities

Methods. Secondary analyses of 17 fiscal quarters of surveys from fourth quarter, FY 2000 through fourth quarter, FY 2004 were conducted for this project. In total, 69,059 surveys with no missing data from Army respondents were analyzed. The report focuses on a descriptive analysis of the results with mean scores of overall patient satisfaction with the clinical experience and their satisfaction with the individual dentist contact.
A Study of the Growth of the Wave Spectrum with Fetch

Abstract The development of the wave spectrum with fetch in a steady wind has been studied with a line of consecutive wave buoys in the Bothnian Sea in 1976 and 1979. The relationship that was found between dimensionless peak frequency ωm (=ωmU10/g) and dimensionless fetch X (=gX/U102) was close to previous observations. The dimensionless energy ¯σ2 (=g2ω2/U104) was about twice that observed in the JONSWAP experiment. In the saturation range when ¯ω>4 the frequency spectrum was found to have the form S(ω) = αuU10gω−4 where αu=4.5 × 10−3, independent of the dimensionless fetch X. The deviation from the Phillips −5 power law could not be explained by the influence of currents or finite depth. Near the peak, the spectra were satisfactorily described by the JONSWAP spectrum; above frequencies twice the peak frequency the difference becomes significant. A qualitative explanation is proposed for the dependence of the spectrum on the wind speed in the saturation range. The semi-theoretical method of Longuet-Hi.
Comparative Analysis of Chlorophyll-a Distribution from SeaWiFS, MODIS-Aqua, MODIS-Terra and MERIS in the Arabian Sea

The variability of Chlorophyll-a (Chl-a) distribution derived from MODIS (on Aqua and Terra platforms) and MERIS sensors have been compared with SeaWiFS data in the Arabian Sea. MODIS Aqua has overestimated the SeaWiFS Chl-a within 25–32% in the coastal turbid (eutrophic) waters and underestimated in open ocean waters with error within 20%. However, there is no significant bias (−0.1 on log-scale) observed as the slope is well within 0.97-1.1 (log transformed). MODIS-Terra has underestimated the Chl-a concentration in open ocean waters by about 29–31%, which is higher than MODIS-Aqua. MODIS-Terra is observed to be more accurate than MODIS-Aqua in the coastal waters. MERIS is overestimating the SeaWiFS Chl-a with log RMS error of ∼0.15 and log bias of ∼0.13–0.2. The differences in the Chl-a estimates between each sensor are possibly due to differences in the sensor design, bio-optical algorithms and also due to the time differences between the satellites over passes. We have examined that the MERIS is performing similar to SeaWiFS and the MODIS-Aqua (Terra) data are reliable in open ocean (coastal) waters. However, Chl-a retrieval algorithms need to be improved especially for coastal turbid waters to continue with SeaWiFS data for long-term studies.
Long‐term landscape evolution: linking tectonics and surface processes

Research in landscape evolution over millions to tens of millions of years slowed considerably in the mid‐20th century, when Davisian and other approaches to geomorphology were replaced by functional, morphometric and ultimately process‐based approaches. Hack's scheme of dynamic equilibrium in landscape evolution was perhaps the major theoretical contribution to long‐term landscape evolution between the 1950s and about 1990, but it essentially ‘looked back’ to Davis for its springboard to a viewpoint contrary to that of Davis, as did less widely known schemes, such as Crickmay's hypothesis of unequal activity. Since about 1990, the field of long‐term landscape evolution has blossomed again, stimulated by the plate tectonics revolution and its re‐forging of the link between tectonics and topography, and by the development of numerical models that explore the links between tectonic processes and surface processes. This numerical modelling of landscape evolution has been built around formulation of bedrock river processes and slope processes, and has mostly focused on high‐elevation passive continental margins and convergent zones; these models now routinely include flexural and denudational isostasy.
Internal gravity wave frequencies and wavenumbers from single point measurements over a slope

It is shown that information about the intrinsic frequency of internal inertial gravity waves, together with their vector wavenumber and their steepness spectrum, may be derived using data from a meter recording current and temperature just above a uniform sloping boundary. The analysis assumes that, over the periods of time in which estimates are made, the local mean buoyancy frequency, N, and temperature gradient are uniform, and the bottom slope, ? , is constant over the scale of the observed waves and is known. It is further assumed that, during short periods of analysis, the internal wave field is dominated by waves having a single wavenumber vector at each frequency. Measurements of the temperature and up-slope current spectra can be used to determine the intrinsic frequency and the along-slope wavenumber, l, of the waves provided the mean along-slope current, V, is non-zero. If the internal wave field near the sloping boundary is composed of perfectly reflecting wave rays, it is found that the ratio, R, of the potential energy density of the waves of given frequency to that of their kinetic energy depends on ? and on the ratio, l/k, of waves in the reflecting wave field, where k is the up-slope wavenumber. Since l is already determined if V ? 0, k may be estimated from the measured R. The third component of wavenumber, m, normal to the slope is found from the dispersion relation. The estimated values may be used to test assumptions of small wave steepness and the uniformity of buoyancy frequency over the vertical scale of the waves. Problems of application are revealed by using the analysis on data collected from a mooring located within the hyperlimnion on the sloping side of Lake Geneva. Whilst the along-slope wavenumbers and corresponding intrinsic frequencies can be found, it proves impossible to derive estimates of wave directions for waves in the subcritical frequency range of group velocities having angles to the horizontal, ? , less than ? , and supercritical waves (? > ? ) have inferred wavelength which violate assumptions of the vertical uniformity of N. It is inferred that in the lake the wave propagation is dominated by waves with a modal structure rather than rays, even near the buoyancy frequency. The methodology should however be applicable in the deep ocean, subject to the various assumptions which are made. Fundamental questions are raised about the directional characteristics and persistence of internal waves near sloping boundaries which deserve further investigation in view of their possible relation to mixing.
CAUSES OF ENGLISH SPELLING ERRORS MADE BY THAI FOREIGN LANGAUGE LEARNERS

This paper aims to account for the underlying causes of spelling errors made by Thai university students. It first presents a general overview of writing and definitions of the relevant terminology in the English writing system. Spelling errors made by Thai university students are then categorised into eight major types. The distinction between English and Thai writing systems which tends to be attributed to the occurrence of Thai learners’ spelling mistakes is accounted for. It is important for both teachers and learners to be aware of underlying causes of spelling errors, in order to assist in minimising erroneous spelling. It is argued that understanding these causes could be of great help not only to second/foreign language (L2/FL) learners, but also to university lecturers in this field.
Depleted mantle-plume geochemical signatures: No paradox for plume theories

High-MgO liquids erupted in ocean-island settings and in some continental flood-basalt provinces commonly preserve a "depleted" composition, in terms of both highly incompatible trace elements and isotope ratios. These observations strongly imply that their source is also compositionally depleted. However, in at least one case (Iceland and the North Atlantic volcanic province), it can be shown that this depleted source is not the same as that feeding the present-day North Atlantic mid-ocean ridge. The depleted source must also have been much hotter than the mid-ocean ridge basalt (MORB) source to account for the volume of melt and primitive composition of some magmas that were generated. This depleted character, then, is an intrinsic component of mantle plumes, originating from the deep mantle. We propose that mantle plumes consist of a mixture of enriched or fusible streaks in a depleted, refractory matrix; preferential extraction of the enriched component occurs close to the plume axis. The depleted residue from this melting remains in the upper mantle and may therefore be a major contributor to the source region of MORB.
Hemispheric roles of climate forcings during glacial‐interglacial transitions as deduced from the Vostok record and LLN‐2D model experiments

The Vostok ice contains fingerprints of atmospheric greenhouse trace gases, Antarctic temperature, Northern Hemisphere temperature, and global ice volume/sea level changes during the last glacial-interglacial cycles and thus allows us to investigate the sequences of these climatic events, in particular during the transitions from full glacial to interglacial conditions. The use of the updated CO2 record presented here and a reexamination of the sea level proxy confirm that the succession of changes has been similar through each of the four marked transitions found at Vostok. Antarctic air temperature and CO2 increase in parallel and almost synchronously, while the rapid warmings over Greenland take place during the last half of their change and coincide with the marked decay in continental ice volume. The Vostok results thus emphasize a fundamental difference between South and North in terms of climate dynamics. Our results confirm the role of CO2 as an important amplifier of the glacial-interglacial warming in the South. It appears also that the marked warming observed at high northern latitudes (lagging behind the CO2 increase by several thousand years) is roughly synchronous with the decay of the northern ice sheets, suggesting a major role of climatic feedback due to this decay. Such a climatic scenario is supported by sensitivity experiments performed with the LLN 2-D model forced by the Northern Hemisphere insolation and CO2. Model results indicate that the decay of the northern ice sheets and the Northern Hemisphere temperature depend primarily on the northern summer insolation. These results, nevertheless, could be affected if mechanisms specific to the Southern Hemisphere appear to play a major role in driving the Northern Hemisphere climate. The model also helps to constrain the time response of ice volume to insolation and CO2 changes.
Band Grouping versus Band Clustering in SVM Ensemble Classification of Hyperspectral Imagery

Due to the dense sampling of spectral signatures of land covers, hyperspectral images have a better discrimination among similar ground cover classes than traditional remote sensing data. However, these images are usually composed of tens or hundreds of spectrally close bands, which result in high redundancy and great amount of computation time in hyperspectral image classifi cation. In addition, the large number of spectral bands, but limited availability of training samples creates the problem of Hughes phenomenon. Consequently, traditional classifi cation strategies have often limited performance in classifi cation of hyperspectral imagery. Referring to the limitation of single classifi ers in these situations, classifi er ensemble system may exhibit better performance. This paper presents a method for classifi cation of hyperspectral data based on two concepts of Band Clustering (BC) and Band Grouping (BG) through a Support Vector machine (SVM) ensemble system. The proposed method uses the BC\BG strategies to split data into few band portions. After this step, we applied SVM on each band cluster\group that is produced in previous step. Finally, Naive Bayes as a classifi er fusion method combines the decisions of SVM classifi ers. Experimental results show that the proposed method improves the classification accuracy in comparison to the standard SVM and to feature selection methods.
Inverse AVO problem for a stack of layers

The problem of estimating thin layered model parameters by amplitude variation with offset (AVO) inversion has been studied. The motivation was resolving of the thin layers in inverted prestack seismic data as it contains more information on elastic properties of the subsurface than poststack seismic data. In this paper, an algorithm for solving the prestack inverse AVO problem in the case of multilayered media is derived. This algorithm is based on iterative corrections to the parameters of the initial model which tend to minimise the misfits between observed and synthetic seismograms. The synthetic seismograms are calculated using the reflection–transmission (RT)-matrices method, assuming a plane-wave with respect to the source position. A regularised Gauss-type algorithm for the inversion of prestack seismic data has been used. A differential seismogram computation algorithm to characterise the sensitivity of the seismic signal to the variations of a model parameter was used. The derived solution of the inverse problem is constructed in the time domain. This gives a slight advantage because it allows for visual control of the solution process. One can monitor the amplitude reduction of the data residual (difference between observed and synthetic seismograms) during the iteration process. Numerical examples show the accuracy and efficiency of the method. The problem of estimating thin layered model parameters by amplitude variation with offset (AVO) inversion of prestack seismic data has been studied. An algorithm for solving the prestack inverse AVO problem in the case of multilayered media has been derived. Numerical examples show the accuracy and efficiency of the method.
Obstacle Avoidance Path Design for Autonomous Vehicles – A Review

Autonomous vehicles are the new revolution in the transportation system. They are designed to improve road efficiency and driving safety. Much research has been undertaken over the years involving significant topics, such as autonomous driving stages and safety, road formation control, obstacle detection, and obstacle avoidance strategies. The implementation of an autonomous driving system relies on several stages. Therefore, a range of different planning approaches are required to ensure safety, comfort, and efficiency. The safety aspect is one of the challenges in self-driving cars as it allows autonomous cars to navigate on the roads. Obstacle detection and obstacle avoidance systems have a major impact on autonomous driving safety. Obstacle detection utilizes the Markov random field (MRF) model that combines three potentials to segment obstacles and non-obstacles in a dangerous environment. Obstacle avoidance applies an improved artificial potential field algorithm to create a collision-free path for autonomous vehicles. In this paper, several approaches and methods are discussed for autonomous vehicles obstacle detection and avoidance systems as well as vehicle formation control techniques. A large number of relevant published papers have been systematically reviewed. Obstacle detection methods and obstacle avoidance approaches for autonomous vehicles are summarized. The results illustrate the efficiency of applied models in optimizing and improving a safe navigating path for autonomous vehicles.
Demography of the Dobe! Kung

First published in 1979, this is a classic study of the population of the Bushmen of the Kalahari Deselt of Botswana. Using methods that are simple and fully illustrated, the author presents empirical descriptions of the fertility, mortality, and marriage patterns of the now famous ! Kung hunter-gatherers. The ! King "Bushman" people of the Kalahari desert in Africa occupy an anomalous position in the world of science. They have been selected for intensive study precisely because they are geographically, socially, and economically removed from modern, industrialized society, living in a sparsely settled and remote portion of an enormous semidesert. The ! Kung maintain the language and culture of a fully develop hunting and gathering society with (until very recently) no dependence on cultivated plants, no domesticated animals other than the dog, no stratification system based on kinship or occupation, no power or authority structure extending further than the local bands composed of a few related families, no wage labor, no use of money, and no settled sites of occupation. At the same time, the ! Kung have become well-known figures to students--both undergraduate and professional--of Western social science. The faces of ! Kung informants gaze from the covers and the illustrations of many texts in anthropology and sociology. Why has all this attention been developed around the ! Kung people? Part of the answer lies in the people themselves. The ! Kung are a physically attractive people, with slender, graceful bodies and open small-featured faces that are appealing and photogenic. Their culture is simple and has its striking features. The struggle for subsistence, the click language, the emphasis on sharing and humility, the drama of the curing dances in which individuals go into trance and speak directly to spirits to cure sickness, and the pervasive humor, teasing, and playfulness of the ! Kung style are all features that are relatively easy to convey and interesting to l earn about. This work covers areas such as marriage, fertility, disease, mortality, history, and the projected future of the ! Kung. This book will be of interest to students of demographic studies, anthropology, and African studies.
Linear and global space‐time dependence and Taylor hypotheses for rainfall in the tropical Andes

[1] The space-time linear and global dependence of tropical rainfall in an intra-Andean valley of Colombia is estimated using 15 min of resolution data, recorded by 18 raingauges, through correlation (ρ) and mutual information (MI) analysis of the entire record (1998–2006) and at seasonal and interannual (ENSO) timescales. Spatial dependence analyses are developed for increasing (1) time aggregation intervals T = 15 min to T = 24 hours, and (2) time lags τ = 15 min to τ = 120 min. Results for (1) indicate that both spatial MI and ρ decay as I(λ, T) = A(T)λ−α(T), but also that A(T) = aTμ and α(T) = bT−ω. Maps of MI and ρ for increasing values of T are discussed in terms of geographical and few known meteorological features. Regarding (2), exponential functions fit better the spatial decay rates of both MI and ρ, such that I(λ, τ) = F(τ)exp[−ϕ(τ)λ], with F(τ) = exp[−dτ], and ϕ(τ) = j−kτ. Maps of MI and ρ for increasing values of τ suggest that MI may be better suited than ρ to capture highly localized singularities of tropical mountain rainfall. Estimated power laws are highly dependent on both the seasonal cycle and ENSO phases, consistently with temporal dynamics of rainfall at both timescales. We tested the validity of Taylor hypothesis ρ(0, τ) = ρ(Uτ, 0) and found it rejected in 11 of 18 raingauges, which prompted us to introduce a global Taylor hypothesis using the space-time MIs as I(0, τ) = I(Uτ, 0). Results indicate that power laws characterize the decay of both the temporal I(0, τ) and the space-transformed I(λ, 0) with respect to τ. A rigorous statistical test indicates that the global Taylor hypothesis is valid in 14 of 18 raingauges within the 20–180 min time range.
Prestack Depth Migration In Angle-domain Using Beamlet Decomposition: Local Image Matrix And Local AVA

A method of local AVA (amplitude versus angle) analysis during the process of prestack depth migration in angle domain is proposed based on the local image matrix obtained through beamlet decomposition (wavelet transform along spatial axis) of both the incident and scattered wave field at the image locality. The local image matrices can be reduced to common refection-angle image (CRAI) gathers and common dip-angle image (CDAI) gathers. CDAI gathers can be used to determine the dip-angle of the reflector and CRAI gathers are then used for local AVA analysis. Preliminary numerical tests demonstrate the feasibility of the method.