• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.65-66
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• 2017

Early-frost damages easily take place in smaller and thinner walls and slabs. In case of slabs, it is difficult to visually determine the depth of early-frost damage. As such, the current study aims to determine the depth of early-frost damage caused to concrete structures due to bad curing in the winter. As a result, the study found that the depth of early-frost damages increased from the top as the atmospheric temperature on the concrete surface decreased. The changes in the color allowed the observer to easily identify the depth of early-frost damage with the naked eye. In particular, the color difference between potentially damaged parts and undamaged parts were the greatest around thirty minutes of drying after wetting.

• Restorative Dentistry and Endodontics
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• 제12권2호
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• pp.83-90
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• 1987

Composite resins has been widely used in dental clinics because of esthetic restoration. The aim of this study was to assess the effects of the cavity designs on the compressive stress of resin restoration. So, the author made the standardized specimen of four types (Type of speciemen are width 1.5mm, depth 2mm, width 1.5mm, depth 3mm, width 2mm, depth 2mm, width 2mm, depth 3mm). The compressive strength was measured by universal testing machine (Tong Kwang Co.) The results indicating following; 1. There was a statistic significance of compressive strength between four cavity forms. 2. There was no difference of significance of compressive strength between two resins. 3. There was a significance of compressive strength between depth 3mm width 1.5mm and depth 3mm width 2mm.

• Current Optics and Photonics
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• 제5권5호
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• pp.514-523
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• 2021

Methods for absolute depth estimation have received lots of interest, and most algorithms are concerned about how to minimize the difference between an input defocused image and an estimated defocused image. These approaches may increase the complexity of the algorithms to calculate the defocused image from the estimation of the focused image. In this paper, we present a new method to recover depth of scene based on a sharpness-assessment algorithm. The proposed algorithm estimates the depth of scene by calculating the sharpness of deconvolved images with a specific point-spread function (PSF). While most depth estimation studies evaluate depth of the scene only behind a focal plane, the proposed method evaluates a broad depth range both nearer and farther than the focal plane. This is accomplished using an asymmetric aperture, so the PSF at a position nearer than the focal plane is different from that at a position farther than the focal plane. From the image taken with a focal plane of 160 cm, the depth of object over the broad range from 60 to 350 cm is estimated at 10 cm resolution. With an asymmetric aperture, we demonstrate the feasibility of the sharpness-assessment algorithm to recover absolute depth of scene from a single defocused image.

• International Journal of Internet, Broadcasting and Communication
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• 제16권2호
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• pp.169-178
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• 2024

This study aimed to investigate the effects of water depth and speed on the activation of lower muscles during squat exercises, utilizing electromyography(EMG). It involved ten male participants in there. Participants performed 30 squats over a minute at a speed of 60bpm and maximum speed squats until exhaustion within a minute. The Integrated electromyography(iEMG) readings for the rectus femoris showed statistically significant differences due to water depth and speed, with a significant interaction effect between depth and speed during squat exercises. The iEMG readings for the biceps femoris also showed statistically significant differences, with a significant interaction effect between depth and speed during squat exercises. The iEMG readings for the gastrocnemius showed statistically significant differences according to water depth and speed. However, the interaction effect of water depth and speed during squat exercises did not show a statistically significant difference. In contrast, the iEMG readings for the tibialis anterior demonstrated statistically significant differences, with a statistically significant interaction effect during squats. These findings suggest that water depth and speed positively influence the activation patterns of lower muscles. Therefore, appropriately tailored aquatic exercises based on water depth for individuals with musculoskeletal discomfort, including the elderly or those with physical impairments, can effectively reduce physical strain and enhance balance, as well as physical and perceptual aspects. It is concluded that such exercises could provide a safer and more effective method of exercise compared to ground-based alternatives.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.212-217
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• 1993

In this paper, the hardening depth in Laser surface hardening process is estimated using a multilayered neural network. Input data of the neural network are surface temperature of five points, power and travelling speed of Laser beam. A FDM(finite difference method) is used for modeling the Laser surface hardening process. This model is used to obtain the network's training data sample and to evaluate the performance of the neural network estimator. The simulational results showed that the proposed scheme can be used to estimate the hardening depth on real time.

• 산업기술연구
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• 제20권A호
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• pp.139-148
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• 2000

A numerical model is represented to calculate the wave fields such as the reflected waves, the transmitted waves, and depth averaged velocities over submerged breakwaters for the normally incident wave trains of nonlinear monochromatic wave. The numerical model is correctly formulated by using both the finite amplitude shallow water equations with the effects of bottom friction and the explicit dissipative Lax-Wendroff finite difference scheme, also satisfactorily verified by comparison with the other results. The behaviors of reflected and transmitted waves with respect to geometric parameters of submerged breakwater such as the slope, crest depth, and crest width are numerically analyzed in this study. In particular, the reflection and transmission coefficients are quantitatively calculated as the function of geometric parameter of submerged breakwater. It is found that the crest depth among parameters related to practical design may be the most important parameter in designing the submerged breakwater. Therefore, the effective and economic performances of submerged breakwater should be depended on the determination of optimal crest depth.

• 한국의학물리학회지:의학물리
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• 제1권1호
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• pp.91-95
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• 1990

The solid state detector system was constructed using commercially available rectifier diode for the assessment of quality assurance in radiotherapy. Dosimetry system which consists of the electrometer and the water phanton was used for measuring small field size scanning. The measured results, which had linearity in accordance with variation of radiation dose for gamma-ray of Co- 60 and 6 and 10MV photons of linear accelerator, showed quite linear characteristics within 1% error. The percent depth dose of 10MV photon of Mevatron KD linear accelerator was measured in small field size using diode, and the results were compared with that of using ion chambers. The results show that the difference of percent depth dose between the value of diode and that of ion chamber was negligible in large field size. However, in small size less than 4$\times$4cm, the difference of percent depth dose estimated by diode and ion chamber was 4.7% by extrapolation to 0$\times$0cm. Considering the smaller volume of diode than that of ion chamber, it might be more reliable to use diode for estimating percent depth dose. Above results suggest that diode can be used for routine check such as beam profile, flatness, symmetry and energy

• 대기
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• 제22권2호
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• pp.175-186
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• 2012

In this study, we investigate the effects of elliptical shape of Asian dust particles on the estimation of aerosol optical depth by implementing T-matrix method into WRF/Chem Dust Model. The phase function calculated by assuming elliptical particle shape near $110{\sim}160^{\circ}$ of scattering angle showed about 20 times larger than that calculated by assuming spherical particle shape. Significant difference of extinction efficiency was found with an increase of size parameter and aspect ratio. From the simulations of two Asian dust events occurred on 1 April 2007 and 16 March 2010, we found that the difference of extinction efficiency between elliptical and spherical particle shape was about 5~8%. The aerosol optical depth calculated by assuming elliptical particle shape with 1.6, 1.4 and 1.2 of aspect ratio was about $4.0{\pm}0.5%$, $2.0{\pm}0.2%$, and $1.0{\pm}0.1%$ larger than those estimated by assuming spherical particle shape.

• Geomechanics and Engineering
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• 제23권1호
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• pp.71-83
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• 2020

Cantilever sheet pile walls are subjected to surcharge loading located on the backfill soil and at different distances from the top of the wall. The response of cantilever sheet pile walls to surcharge loadings at varying distances under seismic conditions is scarce in literature. In the present study, the influence of uniform surcharge load on cantilever sheet pile wall at varying distances from the top of the wall under seismic conditions are analyzed using finite difference based computer program. The results of the numerical analysis are presented in non-dimensional form like variation of bending moment and horizontal earth pressure along the depth of the sheet pile walls. The numerical analysis has been conducted at different magnitudes of horizontal seismic acceleration coefficient and vertical seismic acceleration coefficients by varying the magnitude and position of uniform surcharge from the top of the wall for different embedded depths and types of soil. The parametric study is conducted with different embedded depth of sheet pile walls, magnitude of surcharge on the top of the wall and at a distance from the top of the wall for different angles of internal friction. It is observed that the maximum bending moment increases and more mobilization of earth pressure takes place with increase in horizontal seismic acceleration coefficients, magnitude of uniform surcharge, embedded depth and decrease in the distance of surcharge from the top of the wall in loose sand.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.139-144
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• 2007

To delineate subglacial and englacial images of the western Fourcade Glacier in Antarctica, GPR data were acquired along a 470 m profile in November 2006. Signature deconvolution, migration velocity analysis, and finite difference depth migration were effective in increasing vertical resolution, obtaining the velocity function, and yielding clear depth images of the mixed-phase single-channel data, respectively. The source signature was extracted through stacking reflection signals from the basement. The deconvolution successfully compressed the source signatures to increase temporal resolution and attenuated reverberations. Medium velocities were analyzed with 112 diffraction events by the constant-velocity migration method based on the Stolt algorithm. Finally, depth migration based on the finite difference algorithm provided clear englacial and subglacial images in the laterally-varying velocity field.