• Progress in Medical Physics
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• v.15 no.1
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• pp.39-44
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• 2004

The energy distributions for clinically used electron beams from measured and calculated mono energetic depth dose values were calculated. The energy distributions having the minimum difference between the measured and reduced values of depth dose are determined by iterations based on least square method. The nominal energies of 6, 9, 12, 15 MeV clinical electron beams were examined. The Monte Carlo depth dose calculations with determined energy distributions were peformed to evaluate those distributions. In a comparison of the calculated and measured depth dose data, the standard errors are estimated within $\pm$ 3% from surface to R$_{80}$ depth and within $\pm$4% from the surface to near the range for all electron beams. This can be practically applied to determine the energy distributions for clinically used electron beams.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.177-184
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• 2013

This study analyzed the hydraulic characteristics of a venturi flume with a circular cone using a 3-D numerical model which uses RANS(Reynolds-Averaged Navier-Stokes Equation) as the governing equation. The venturi flume with the circular cone efficiently measures the discharge in the low-flow to high-flow range and offers the advantage of accurate discharge measurements in the case of a low flow. With no influence of the tail-water depth, the stage-discharge relationship and the flow behaviors were analyzed to verify the numerical simulation results. Additionally, this study reviewed the effect of the tail-water depth on the flow. The stage-discharge relationship resulting from a numerical simulation in the absence of an effect by the tail-water depth showed a maximum margin of error of 4 % in comparison to the result of a hydraulic experiment. The simulation results reproduced the overall flow behaviors observed in the hydraulic experiment well. The flow starts to become influenced by the tail-water depth when the ratio of the tail-water depth to the total head exceeds approximately 0.7. As the ratio increases, the effect on the flow tends to grow dramatically. As shown in this study, a numerical simulation is effective for identifying the stage-discharge relationship of a venturi flume with various types of venturi bodies, including a venturi flume with a circular cone.

• Computers and Concrete
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• v.27 no.1
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• pp.1-12
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• 2021

This work presents a safety assessment of an underground tunnel subjected to a ballistic missile attack employing the numerical approach. For the impact simulation, a box shaped reinforced concrete (RC) structure with a cross section dimension of 8.0×10.0 m under a soil layer that was attacked by a SCUD missile was modeled using finite element (FE) software LS-DYNA. SCUD missile is one of a series of tactical ballistic missiles developed by Soviet Union during the Cold War, which is adopted for a short-range ballistic missile. The developed FE simulation for the penetration depth of the missile impacting into the soil structure was verified from the well-known formula of the penetration prediction. The soil-structure interaction, the soil type, and the impact missile velocity effects on the penetration depth of the missile into the different soil types were investigated. The safety assessment of the underground tunnel was performed with regard to the different depths of the underground tunnel. For each missile velocity and soil type, a specific depth called the unsafe depth was obtained from the analysis results. The structure beneath the soil beyond this depth remains safe. The unsafe depth was found to be increased with the increasing missile velocity.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.97-101
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• 2021

In this study, Insertion loss according to the structural variant of interposer to Through Silicon Via (TSV) and Redistributed Layer (RDL) was studied through design of experiment. 3-Factors was considered as a variant, TSV depth, TSV diameter, RDL width with factor arrangement method and the response surface method from 400 MHz to 20 GHz. As a result, it was confirmed that as the frequency increased, the effect of RDL width was decreased and the effect of TSV depth and TSV diameter was increased. Also within the analysis range, to increasing RDL width, decreasing TSV depth, and fixing TSV diameter about 10.7 ㎛ was observed optimal result of Insertion loss.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.315-322
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• 2001

Underground flexible pipes for electric cables are subject to external loads and surrounding soil pressure. Particularly, strain of flexible pipes is of great concern in terms of safety and maintenance for electric cables. In this paper, stress and strain of flexible pipes with various depth are calculated using traditional formula and FEM analysis. The results show that theoretical values are more conservative in strain whereas FEM analysis gives larger stress. Considering the strain criteria - 3.5 %, maximum, flexible pipes can be buried at the range of 50cm to 5m in depth without additional soil improvement.

• Journal of Multimedia Information System
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• v.3 no.2
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• pp.43-46
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• 2016

This article will compare the following visual categories: visual angle, distinguishable details, sensitivity, and dynamic range. These categories are often considered within the subject of the maximum deviation from the camera eye, an issue which has generated much controversy. Other characteristics such as depth of field, three-dimensional vision, white balance and color, are not considered in this article.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1103-1106
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• 2009

In this paper, we investigated the properties of hypostereoscopic condition in mobile circumstance and simulated the main factors to embody an effective presence to the reconstructed depth image, which are both the limited disparity for fusible stereo and the object space possible for quantifying.

• Magazine of the Korea Concrete Institute
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• v.20 no.3
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• pp.20-25
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• 2008

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.294-299
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• 2007

For efficient and accurate diagnosis of ultrasound images, appropriate time gain compensation(TGC) and dynamic range(DR) control of ultrasound echo signals are important. TGC is used for compensating the attenuation of ultrasound echo signals along the depth, and DR controls the image contrast. In recent ultrasound systems, these two factors are automatically set by a system and/or manually adjusted by an operator to obtain the desired image quality on the screen. In this paper, we propose an algorithm to find the optimized parameter values far TGC and DR automatically. In TGC optimization, we determine the degree of attenuation compensation along the depth by dividing an image into vertical strips and reliably estimating the attenuation characteristic of ultrasound signals. For DR optimization, we define a novel cost function by properly using the characteristics of ultrasound images. We obtain experimental results by applying the proposed algorithm to a real ultrasound(US) imaging system. The results verify that the proposed algorithm automatically sets values of TGC and DR in real-time such that the subjective quality of the enhanced ultrasound images may be sufficiently high for efficient and accurate diagnosis.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.68-71
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• 2001

This paper has been studied for a comparison of the propagation and noise characteristics between ultrasonic and electromagnetic wave for the high speed communication of the short range telemetry. We analyze the propagation depth of electromagnetic and ultrasonic wave by skin depth effect and by ultrasonic loss ratio. We also studied several effects such as near field effect in electromagnetic wave and Rayleigh scattering noise of ultrasonic wave, etc. We show the experimental results of their propagation loss and modulation experiments in water. The experimental results show that both method is good for the implementation of short range telemetry.