• Smart Structures and Systems
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• v.13 no.5
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• pp.755-773
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• 2014

The natural frequency of a bridge is an important parameter in many engineering applications such as bridge seismic design and modal-based bridge health monitoring. The natural frequency of a bridge vibrating alone may differ from that vibrating along with a vehicle. Although such vehicle-induced variability in bridge frequency is revealed in several experimental and numerical simulation studies, few attempts have been made on the theoretical descriptions. In this study, both theoretically and experimentally, the variability in the bridge frequency induced by a parked vehicle is verified, and is therefore suggested to be considered in bridge-related engineering, especially for those cases with near vehicle-bridge resonance conditions or with large vehicle-to-bridge mass ratios. Moreover, the variability ranges could be estimated by an analytical formula presented herein.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.482-484
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• 2003

GLI on boarded ADEOS-II satellite allows us to observe vegetation status in the two different resolutions simultaneously, because of thirty 1km resolution channels and six 250m resolution channels. There are four GLI land higher level products from these channels ; those are PGCP (Precise Geometric Correction Parameter), L2A_LC (TOA reflectance), ACLC (atmospheric corrected reflectance), and VGI (NDVI and EVI). This paper shows ADEOS-II GLI land data processing, and some of the latest results.

• Journal of the Korean GEO-environmental Society
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• v.20 no.9
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• pp.13-19
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• 2019

Dynamic earth pressure is considered an important parameter in the design of embedded structures. In current engineering design simplified methods developed either for yielding or non-yielding structures are utilized to predict resultant dynamic pressure. The applicability of these equations to embedded structures have not yet been reported. In this study we perform a suite of equivalent linear time history analysis for a range of embedded structure configurations. Numerically calculated dynamic pressure is shown to depend on the flexibility ratio (F), aspect ratio (L/H) of the embedded structure, and ground motion. Increase in L/H and intensity increases the magnitude of dynamic pressure. An increase in F decreases the dynamic pressure. Overall, the trends highlight the need for development of new method that accounts for F and L/H to calculate the dynamic pressure for the performance-based design of embedded structures.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.397-400
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• 2007

For mapping the distribution of heavy metals in the mining area, field spectroscopy and hyperspectral remote sensing were used in this study. Although heavy metals are spectrally featureless from the visible to the short wave infrared range, possible variations in spectral signal due to heavy metals bound onto minerals can be explained with the metal binding reaction onto the mineral surface. Variations in the spectral absorption shapes of lattice OH and oxygen on the mineral surface due to the combination of heavy metals were surveyed over the range from 420 to 2400 nm. Spectral parameters such as peak ratio and peak area were derived and statistically linked to metal concentration levels in the streambed samples collected from the dry stream channels. The spatial relationships between spectral parameters and concentrations of heavy metals were yielded as well. Based on the observation at a ground level for the relationship between spectral signal and metal concentration levels, the spectral parameters were classified in a hyperspectral image and the spatial distribution patterns of classified pixels were compared with the product of analysis at the ground level. The degree of similarity between ground dataset and image dataset was statistically validated. These techniques are expected to support assessment of dispersion of heavy metal contamination and decision on optimal sampling point.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.12-15
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• 2004

Groundwater contamination susceptibility studies have many advantages in groundwater monitoring, management and future planning. Several methods have been developed and applied to the groundwater regime through out the world. However, each and every method has some limitations. In this study, a detailed review was carried out about the already existing methods for groundwater contamination susceptibility studies. Additionally, a new parameter called mineral dissolution factor is recommended for groundwater contamination susceptibility studies. This parameter is applied for groundwate contamination susceptibility studies in Namwon area, Korea. The result of this approach suggests that mineral dissolution parameter could overcome the limitations as observed in the earlier methods.

• Journal of the Korean Geophysical Society
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• v.4 no.3
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• pp.175-182
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• 2001

We consider the problem of determining smoothing parameters of Gibbs priors for Bayesian methods used in the medical imaging application of emission tomographic reconstruction. We address a simple smoothing prior (membrane) whose global hyperparameter (the smoothing parameter) controls the bias/variance tradeoff of the solution. We base our maximum-likelihood (ML) estimates of hyperparameters on observed training data, and argue the motivation for this approach. Good results are obtained with a simple ML estimate of the smoothing parameter for the membrane prior.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.88-91
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• 2009

For lightning currents, a grounding system shows the transient grounding impedance characteristics. A grounding system for protection against lightning should be evaluated by the transient grounding impedance, not it's ground resistance. The transient grounding impedance varies with the shape of ground electrode and earth characteristics as well as the waveform of lightning surge current. For the analysis and practical use of transient grounding impedance, the characteristics of transient grounding impedance should be analyzed theoretically and this paper suggests the theoretical analysis for the transient grounding impedance of counterpoise by using the distributed parameter circuit model. EMTP and Matlab are used to simulate the distributed parameter circuit model of counterpoise and the adequacy of the distributed parameter model of counterpoise is examined by comparing the simulated results with the measured results.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1212-1214
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• 2003

The usual technique of correction and positioning of film image of RS require enough control points to provide the geographic coordinate. Some distortion and error caused by earth curvature and terrain and photograph tilt can't be eliminated by these ways. In this paper a set of technique of systemic correction and positioning of remote sensing image base on orbit parameter is described, some questions in its realization and their solvent also included.

• Geomechanics and Engineering
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• v.23 no.2
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• pp.165-178
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• 2020

This paper investigates the effect of the jaw's curvature, also known by contact angle and jaw arc central angle (2α), of the Brazilian test apparatus on indirect tensile strength of various rock types. That's why, ten rock samples including limestone, marble, skarn, granite, diorite, and granodiorite were collected from some quarries in different provinces of Iran. Petrographic, mineralogical and textural investigations were performed using thin section analyses. Physical properties of the selected rock samples namely dry and saturated unit weights, porosity, water absorption, and specific gravity were determined for the rock samples. In addition, Brazilian tensile strength at different 2α angles (i.e., 2α = 0°, 10°, 15°, 20°, 45°, and 60°) were determined for the rocks in the laboratory. Results show that the parameter for the rocks is between 3.81 MPa at 2α=0° and 54.76 MPa at 2α=60°. This means that Brazilian tensile strength increased with increasing 2α angle from 0° to 60°. Also, it was found that the highest change rate of the Brazilian tensile strength occurs in range of 2α=15°-30° for most studied rock samples. In some tested samples, the parameter is decreased only at 2α = 60°. The values of Brazilian tensile strength of the rocks tested by flat and standard jaws are near to each other.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.231-239
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• 2022

The irregular shape of the disturbances is a fundamental issue for mining engineers at the Sidi Chennane phosphate deposit in Morocco. A precise classification of disturbed areas is therefore necessary to understand their part in the overall volume of phosphate. In this paper, we investigate the theoretical and practical aspects of studying and measuring multifractal spectrums as a defining and representative parameter for distinguishing between the phosphate deposit of a low rate of disturbances and the deposit of a high rate. An empirical multifractal approach was used by analyzing the disturbed areas through the geoelectric images of an area located in the Sidi Chennane phosphate deposit. The Generalized fractal dimension, D(q), the Singularities of strength, α(q), the local dimension, f(α) and their conjugate parameter the mass exponent, τ(q) as well as f(α)-α spectrum were the common multifractal parameters used. The results reported show wide variations of the analyzed images, indicating that the multifractal analysis is an indicator for evaluate and characterize the disturbed areas within the phosphates deposits through the studied geoelectric images. This could be the starting point for future work aimed at improving phosphate exploration planning.