A hybrid predictive model of unstable rock blocks around a tunnel based on estimated volumetric fracture intensity and circular variance from borehole data sets

Kappa ([Formula: see text]) describes the amplitude decay of acceleration Fourier spectrum at high frequencies. Using the records of K-NET and KiK-net stations during the mainshock of the 2011 Great East Japan Earthquake, we examine if the typical measurement method of [Formula: see text] can be extended to this size of event and how propagation path and site condition affect [Formula: see text]. The strength of the linear relationship between epicentral distance and [Formula: see text] is the most apparent in the KiK-net borehole data; for other data sets, the statistical significance of the best-fitting logarithmic model is more tenuous. Our study on site effects reveals that high-frequency amplitudes diminish about 20% at soft soil stations than they do at hard rock stations. The effect on high-frequency filters is around diminution in most cases. And, the effect of nonlinear site response on [Formula: see text] values can be observed.

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Random forest predictive model development with uncertainty analysis capability for the estimation of evapotranspiration in an arid oasis region

Hydrology Research ◽

10.2166/nh.2020.012 ◽

2020 ◽

Vol 51 (4) ◽

pp. 648-665

Author(s):

Min Wu ◽

Qi Feng ◽

Xiaohu Wen ◽

Ravinesh C. Deo ◽

Zhenliang Yin ◽

...

Keyword(s):

Random Forest ◽

Uncertainty Analysis ◽

Predictive Model ◽

Air Temperature ◽

Model Development ◽

Influential Factor ◽

Weather Data ◽

Data Sets ◽

Oasis Area ◽

Lower Uncertainty

Abstract The study evaluates the potential utility of the random forest (RF) predictive model used to simulate daily reference evapotranspiration (ET0) in two stations located in the arid oasis area of northwestern China. To construct an accurate RF-based predictive model, ET0 is estimated by an appropriate combination of model inputs comprising maximum air temperature (Tmax), minimum air temperature (Tmin), sunshine durations (Sun), wind speed (U2), and relative humidity (Rh). The output of RF models are tested by ET0 calculated using Penman–Monteith FAO 56 (PMF-56) equation. Results showed that the RF model was considered as a better way to predict ET0 for the arid oasis area with limited data. Besides, Rh was the most influential factor on the behavior of ET0, except for air temperature in the proposed arid area. Moreover, the uncertainty analysis with a Monte Carlo method was carried out to verify the reliability of the results, and it was concluded that RF model had a lower uncertainty and can be used successfully in simulating ET0. The proposed study shows RF as a sound modeling approach for the prediction of ET0 in the arid areas where reliable weather data sets are available, but relatively limited.

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Three-dimensional imaging of a Ag-Au-rich epithermal system in British Columbia, Canada, using airborne z-axis tipper electromagnetic and ground-based magnetotelluric data

Geophysics ◽

10.1190/geo2015-0230.1 ◽

2016 ◽

Vol 81 (1) ◽

pp. B1-B12 ◽

Cited By ~ 8

Author(s):

Juliane Hübert ◽

Benjamin M. Lee ◽

Lijuan Liu ◽

Martyn J. Unsworth ◽

Jeremy P. Richards ◽

...

Keyword(s):

British Columbia ◽

Volcanic Rocks ◽

Three Dimensional ◽

Data Sets ◽

Borehole Data ◽

Magnetotelluric Data ◽

Electric Field Amplitude ◽

Epithermal System ◽

Geologic Model ◽

Felsic Volcanic

We have evaluated results from a study combining airborne z-axis tipper electromagnetic (ZTEM) and ground-based magnetotelluric (MT) data to image an epithermal system in British Columbia. The spatially coincident use of these two methods allowed for a direct comparison of both data sets in the overlapping frequency band and showed that both measurements were consistent. Inversion of just the ZTEM data suffered from the lack of electric field amplitude information, which could be provided by the MT data. Three-dimensional inversion modeling of the two individual data sets was performed. Models of electrical resistivity derived from both data sets were consistent and could be correlated with the geological and structural setting of the mineralization. Gold is associated with disseminated pyrite and marcasite in quartz-sericite-altered felsic volcanic rocks and intrusions, especially near the contact with mafic volcanic rocks and a late diorite intrusion. The quartz-sericite alteration yields a conductivity anomaly, relative to the more resistive mafic country rocks. Although ZTEM and MT do not possess the resolution of the geologic model derived from borehole data, our model agrees well with a regional assessment of the deposit.

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Joint inversion of surface and three‐component borehole magnetic data

Geophysics ◽

10.1190/1.1444749 ◽

2000 ◽

Vol 65 (2) ◽

pp. 540-552 ◽

Cited By ~ 100

Author(s):

Yaoguo Li ◽

Douglas W. Oldenburg

Keyword(s):

Field Data ◽

Joint Inversion ◽

Magnetic Data ◽

Data Sets ◽

Source Depth ◽

Inversion Algorithm ◽

Borehole Data ◽

Weighting Functions ◽

Surface Data ◽

Geometric Decay

The inversion of magnetic data is inherently nonunique with respect to the distance between the source and observation locations. This manifests itself as an ambiguity in the source depth when surface data are inverted and as an ambiguity in the distance between the source and boreholes if borehole data are inverted. Joint inversion of surface and borehole data can help to reduce this nonuniqueness. To achieve this, we develop an algorithm for inverting data sets that have arbitrary observation locations in boreholes and above the surface. The algorithm depends upon weighting functions that counteract the geometric decay of magnetic kernels with distance from the observer. We apply these weighting functions to the inversion of three‐component magnetic data collected in boreholes and then to the joint inversion of surface and borehole data. Both synthetic and field data sets are used to illustrate the new inversion algorithm. When borehole data are inverted directly, three‐component data are far more useful in constructing good susceptibility models than are single‐component data. However, either can be used effectively in a joint inversion with surface data to produce models that are superior to those obtained by inversion of surface data alone.

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Regional aquifer mapping using combined VES-TEM-AMT/EMAP methods in the semiarid eastern margin of Parnaiba Basin, Brazil

Geophysics ◽

10.1190/1.1444539 ◽

1999 ◽

Vol 64 (2) ◽

pp. 337-356 ◽

Cited By ~ 52

Author(s):

M. A. Meju ◽

S. L. Fontes ◽

M. F. B. Oliveira ◽

J. P. R. Lima ◽

E. U. Ulugergerli ◽

...

Keyword(s):

Large Scale ◽

Structural Information ◽

Integration Scheme ◽

Data Sets ◽

Borehole Data ◽

Eastern Margin ◽

Transient Electromagnetic ◽

Hydrogeological Studies ◽

East West ◽

Parnaíba Basin

As part of a program to evaluate the utility of integrated geoelectrical methods for subsurface structural mapping and groundwater resource investigation in the semiarid eastern margin of the Parnaiba basin in Brazil, several vertical electrical soundings (VES) and transient electromagnetic (TEM) and tensorial audiomagnetotelluric (AMT) measurements were carried out along a 250-km-long east‐west transect (passing through major towns and cities) and a 127-km-long north‐south profile (passing through small farm settlements). The various data sets have been jointly processed using a novel integration scheme and a constrained 1-D inversion technique to yield the resistivity structure underneath each observation station. Regularized 2-D inversion of static‐shift‐corrected, dual‐mode AMT data provided additional deep structural information and, together with the joint 1-D results, enabled an assessment of the distribution of aquifers and major structural controls in the region. The east‐west regional geoelectrical model evokes a picture of a gently dipping succession of conductive and resistive units in good agreement with the alternating shaly and sandy formations evinced from preexisting borehole data and previous geological studies. The geoelectric models also show the presence of the large‐scale Transbrazilian lineament and other graben‐like structures, previously inferred from aeromagnetic data, which may have some control on groundwater distribution. The agreement with geology and aeromagnetic interpretation emphasizes the importance of integrated geoelectrical surveying as a complementary or independent means of obtaining useful stratigraphic and structural information for hydrogeological studies in this region.

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Modeling the Growth of Listeria monocytogenes in Soft Blue-White Cheese

Applied and Environmental Microbiology ◽

10.1128/aem.01865-12 ◽

2012 ◽

Vol 78 (24) ◽

pp. 8508-8514 ◽

Cited By ~ 23

Author(s):

Per Sand Rosshaug ◽

Ann Detmer ◽

Hanne Ingmer ◽

Marianne Halberg Larsen

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Physicochemical Properties ◽

Predictive Model ◽

Growth Conditions ◽

Data Sets ◽

Growth Data ◽

Content Type ◽

White Cheese ◽

Over Time

ABSTRACTThe aim of this study was to develop a predictive model simulating growth over time of the pathogenic bacteriumListeria monocytogenesin a soft blue-white cheese. The physicochemical properties in a matrix such as cheese are essential controlling factors influencing the growth ofL. monocytogenes. We developed a predictive tertiary model of the bacterial growth ofL. monocytogenesas a function of temperature, pH, NaCl, and lactic acid. We measured the variations over time of the physicochemical properties in the cheese. Our predictive model was developed based on broth data produced in previous studies. New growth data sets were produced to independently calibrate and validate the developed model. A characteristic of this tertiary model is that it handles dynamic growth conditions described in time series of temperature, pH, NaCl, and lactic acid. Supplying the model with realistic production and retail conditions showed that the number ofL. monocytogenescells increases 3 to 3.5 log within the shelf life of the cheese.

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Parallel structural interpretation of drill cores and microresistivity scanner images from gas-bearing shale (Baltic Basin, Poland)

Interpretation ◽

10.1190/int-2017-0211.1 ◽

2018 ◽

Vol 6 (3) ◽

pp. SH25-SH38 ◽

Cited By ~ 6

Author(s):

Kinga Bobek ◽

Marek Jarosiński

Keyword(s):

Striking Difference ◽

Data Sets ◽

Fracture Density ◽

Baltic Basin ◽

Structural Interpretation ◽

The Core ◽

Calcite Veins ◽

Fracture Intensity ◽

Core Profile ◽

Drill Cores

Having access to drill cores and microresistivity scanner images from five shale gas exploration boreholes, we were able to compare the results of structural interpretation based on two data sets. The most frequent structures observed in shale complexes are subvertical strata-bound joints that commonly create calcite veins. We have applied a modified approach for statistical analysis of strata-bound fractures taking into account their height. For comparison of cores and scanner image log structural interpretations, we used the fracture number and fracture intensity parameters. We found significant discrepancies between results of cores and image log interpretations. The much greater number of fractures recognized in the image log than in the core is explained by differences in the observation space related to the core and borehole diameters. To predict which fracture that was visible in the scanner image should be represented in the core, we introduced a “critical angle” parameter and used it in the filtering procedure, which gave satisfactory results. In general, the systematically observed superiority of fracture intensity in the scanner image over the core profile is explained by a large number of tiny noncracked veins that are better recorded by a scanner then are visible by the unaided eye. The most striking difference was found in carbonate-rich formations, in which noncracked veins are more numerous. On the contrary, fracture intensity in intervals enriched in total organic carbon (TOC) is always higher in core than in the scanner image, due to a resistivity enhancement related to gas presence. We also compared a record of en echelon arrays of open fractures that allow us to discriminate enhanced natural fractures from borehole-induced tensile fractures. A major difference in the bedding fracture density between the core and image log we attribute to core relaxation during its extraction to the surface. A tectonic inversion phase was also possible to recognize based on the integrated core and scanner interpretation.

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3-D inversion of induced polarization data

Geophysics ◽

10.1190/1.1444877 ◽

2000 ◽

Vol 65 (6) ◽

pp. 1931-1945 ◽

Cited By ~ 87

Author(s):

Yaoguo Li ◽

Douglas W. Oldenburg

Keyword(s):

Wavelet Transforms ◽

Joint Inversion ◽

Linear Equations ◽

Induced Polarization ◽

Dc Resistivity ◽

Data Sets ◽

Bound Constraints ◽

Borehole Data ◽

Resistivity Data ◽

Logarithmic Barrier

We present an algorithm for inverting induced polarization (IP) data acquired in a 3-D environment. The algorithm is based upon the linearized equation for the IP response, and the inverse problem is solved by minimizing an objective function of the chargeability model subject to data and bound constraints. The minimization is carried out using an interior‐point method in which the bounds are incorporated by using a logarithmic barrier and the solution of the linear equations is accelerated using wavelet transforms. Inversion of IP data requires knowledge of the background conductivity. We study the effect of different approximations to the background conductivity by comparing IP inversions performed using different conductivity models, including a uniform half‐space and conductivities recovered from one‐pass 3-D inversions, composite 2-D inversions, limited AIM updates, and full 3-D nonlinear inversions of the dc resistivity data. We demonstrate that, when the background conductivity is simple, reasonable IP results are obtainable without using the best conductivity estimate derived from full 3-D inversion of the dc resistivity data. As a final area of investigation, we study the joint use of surface and borehole data to improve the resolution of the recovered chargeability models. We demonstrate that the joint inversion of surface and crosshole data produces chargeability models superior to those obtained from inversions of individual data sets.

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An Efficient Classification Model using Fuzzy Rough Set Theory and Random Weight Neural Network

Lahore Garrison University Research Journal of Computer Science and Information Technology ◽

10.54692/lgurjcsit.2021.0503224 ◽

2021 ◽

Vol 5 (3) ◽

pp. 92-108

Author(s):

Rana Aamir Raza

Keyword(s):

Neural Network ◽

Predictive Model ◽

Set Theory ◽

Rough Set ◽

Large Scale ◽

Rough Set Theory ◽

Classification Model ◽

Data Sets ◽

Fuzzy Rough Set ◽

Random Weight

In the area of fuzzy rough set theory (FRST), researchers have gained much interest in handling the high-dimensional data. Rough set theory (RST) is one of the important tools used to pre-process the data and helps to obtain a better predictive model, but in RST, the process of discretization may loss useful information. Therefore, fuzzy rough set theory contributes well with the real-valued data. In this paper, an efficient technique is presented based on Fuzzy rough set theory (FRST) to pre-process the large-scale data sets to increase the efficacy of the predictive model. Therefore, a fuzzy rough set-based feature selection (FRSFS) technique is associated with a Random weight neural network (RWNN) classifier to obtain the better generalization ability. Results on different dataset show that the proposed technique performs well and provides better speed and accuracy when compared by associating FRSFS with other machine learning classifiers (i.e., KNN, Naive Bayes, SVM, decision tree and backpropagation neural network).

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