• Journal of the Korea Safety Management & Science
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• v.2 no.3
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• pp.27-36
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• 2000

The Robust Design method uses a mathematical tool called orthogonal arrays to study a large number of decision variables with a small number of experiments. It also uses a new measure of quality, called signal-to-noise (S/N) ratio, to predict the quality from the customer's perspective. Thus, the most economical product and process design from both manufacturing and customers' viewpoints can be accomplished at the smallest, affordable development cost. Many companies, big and small, high-tech and low-tech, have found the Robust Design method valuable in making high-quality products available to customers at a low competitive price while still maintaining an acceptable profit margin. A study to analyze and solve problems of a biochemical process experiment has presented in this paper. We have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/N ratio.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.12
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• pp.771-775
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• 2015

In this paper, we designed and fabricated low cost imprinting process for micro patterning on FCCL (flexible copper clad laminate). Compared to conventional imprinting process, developed fabrication method processing imprint and UV photolithography step simultaneously and it does not require resin etch process and it can also reduce the fabrication cost and processing time. Based on proposed method, patterns with $10{\mu}m$ linewidth are fabricated on $180mm{\times}180mm$ FCCL. Compared to conventional methods using LDI (laser direct imaging) equipment that showed minimum line with $10{\sim}20{\mu}m$, proposed method shows comparable pattern resolution with very competitive price and shorter processing time. In terms of mass production, it can be applied to fabrication of large-area low cost applications including FPCB.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.4
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• pp.103-114
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• 1998

The floors of building structures equipped with vibrating machines can be susceptible to large vibration as a result of resonance or beating. Such a vibration can be reduced efficiently by using tuned mass dampers. However, the effectiveness of the damper depends greatly on the location and the natural frequency of the damper. To determine the optimum damper location is especially important since the dynamic behavior of a building structure varies with the location of the input loading. To this end, it is intended to decide the location and natural frequency of tuned mass dampers for reducing vibration of both loaded floors and floors located nearby the loaded floors considering the location and frequency components of the loading. The Vector composition method and the super elements are used th obtain the responses in steady states, and the optimum damper location and natural frequencies were found with the given damper mass.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.249-252
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• 2008

In recent large-scale structures, as mass concrete type structure is frequently applied to the building, temperature crack due to hydration heat needs to be considered. Since a volume change is internally or externally restricted in a mold after placing concrete, temperature crack of mass concrete takes place. By this reason, the reduction method to control this crack is required. In this study, low heat mixture and hydration heat difference is used to execute the analysis of hydration heat, considering the changes of heat transfer coefficient according to curing conditions and block placement of mass concrete. For the analytical modelling, original portland cement and concrete of low heat mixture are placed in the upper and lower payer, respectively. A convection boundary condition is fixed because mass concrete of block placement is characterized by the difference of mold form and curing condition. Through the analysis results considering the changes of low heat mixture, block placement, and heat transfer coefficient, we check out the temperature and stress distribution and analyze the temperature crack reduction effect.

• Journal of Sensor Science and Technology
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• v.29 no.1
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• pp.33-39
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• 2020

Typically, photoacoustic images are obtained in water or gelatin because the impedance of these mediums is similar to that of the human body. However, these acoustic mediums can have an additional mass effect that changes the resonance frequency of the transducer. The acoustic radiation impedance in air is negligible because it is very small compared to that of the transducer. However, the high acoustic impedance of mediums such as the human body and water is quite large compared to that of air, making it difficult to ignore. Specifically, in a case where the equivalent mass is very small, such as with a micro-machined ultrasound transducer, the additional mass effects of the acoustic medium should be considered for an accurate resonance frequency design. In this study, a piezoelectric micro-machined ultrasonic transducer (pMUT) was designed to have a resonance frequency of 10 MHz in the acoustic medium of water, which has similar impedance as the human body. At that time, the resonance frequency of the pMUT in air was calculated at 15.2 MHz. When measuring the center displacement of the manufactured pMUT using a laser vibrometer, the resonance frequencies were measured as 14.3-15.1 MHz, which is consistent with the finite element method (FEM) simulation results. Finally, photoacoustic images of human hair samples were successfully obtained using the fabricated pMUT.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.4
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• pp.25-30
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• 2000

Ion mass doping method has been implemented for the fabrication of large area electronic devices such as TFT-LCD. In this work, the effect of ion mass doping on the velocity and the behavior of MILC was investigated. When amorphous silicon was either doped or bombarded by accelerated ions, MILC velocity was reduced by over 50% and the front edge of MILC became coarse. In order to analyze the dependence of silicon film's properties on ion mass doping, ultraviolet reflectance and sulfate roughness were investigated. Both the velocity and the behavior of MILC were found to be related with the increase of surface roughness by ion bombardment.

• Nutrition Research and Practice
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• v.15 no.1
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• pp.95-105
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• 2021

BACKGROUND/OBJECTIVES: The measurement of body composition, including muscle and fat mass, remains challenging in large epidemiological studies due to time constraint and cost when using accurate modalities. Therefore, this study aimed to develop and validate prediction equations according to sex to measure lean body mass (LBM), appendicular skeletal muscle mass (ASM), and body fat mass (BFM) using anthropometric measurement, serum creatinine level, and lifestyle factors as independent variables and dual-energy X-ray absorptiometry as the reference method. SUBJECTS/METHODS: A sample of the Korean general adult population (men: 7,599; women: 10,009) from the Korean National Health and Nutrition Examination Survey 2008-2011 was included in this study. The participants were divided into the derivation and validation groups via a random number generator (with a ratio of 70:30). The prediction equations were developed using a series of multivariable linear regressions and validated using the Bland-Altman plot and intraclass correlation coefficient (ICC). RESULTS: The initial and practical equations that included age, height, weight, and waist circumference had a different predictive ability for LBM (men: R2 = 0.85, standard error of estimate [SEE] = 2.7 kg; women: R2 = 0.78, SEE = 2.2 kg), ASM (men: R2 = 0.81, SEE = 1.6 kg; women: R2 = 0.71, SEE = 1.2 kg), and BFM (men: R2 = 0.74, SEE = 2.7 kg; women: R2 = 0.83, SEE = 2.2 kg) according to sex. Compared with the first prediction equation, the addition of other factors, including serum creatinine level, physical activity, smoking status, and alcohol use, resulted in an R2 that is higher by 0.01 and SEE that is lower by 0.1. CONCLUSIONS: All equations had low bias, moderate agreement based on the Bland-Altman plot, and high ICC, and this result showed that these equations can be further applied to other epidemiologic studies.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.481-489
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• 2023

Purpose: The purpose of this study is to examine the actual disaster response and suggest improvement measures for introduction of an autonomous police system Method: This study suggests the improvement measures by reviewing police disaster response manual, related statistical data, and statutes comprehensively Result: The introduction of autonomous police system enabled effective management of police based on circumstances of each region. However, there are still doubts on police response against situations that require large number of personnel. According to analysis on roles of autonomous police during the mass disasters, the autonomous police controlled disaster site to prevent secondary damage, prevented additional disaster damages, and rescued people. However, it is hard for the autonomous police to respond against the mass disasters due to its structure. Conclusion: To improve the response of autonomous police against mass disasters, this study suggested on disaster scene control and secondary damage prevention by the police, cooperative disaster response with regional autonomous police, and utilization of control tower.

• International Journal of Air-Conditioning and Refrigeration
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• v.10 no.3
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• pp.162-175
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• 2002

To investigate smoke movement with radiation in a room fires, a numerical and experi-mental analysis were performed. In this paper, results from a field model based on a self-developed SMEP (Smoke Movement Estimating Program) were compared with Stockier's ex-periment and the experiments on various sized pool fires in a room with door The SMEP using PISO algorithm solves conservation equations for mass, momentum, energy and species, together with those for the modified k- $\varepsilon$ turbulence model with buoyancy term. Also it solves the radiation equation using the S-N discrete ordinates method (DOM). The result of the cal-culated smoke temperature considering radiation effect has shown good agreement compared with the experimental data, although there are large discrepancy in the hot smoke layer be-tween the temperature predicted by the SMEP with only convection effect and obtained by the experimental result. This large discrepancy is caused from the radiation effect of $H_2O$ and $CO_2$ gas under smoke productions. Hence the radiation effect under smoke in fire is the point to be specially considered in order to produce more realistic result.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.16-21
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• 2003

The very large container ships have been built recently and those ships have very small structural rigidity compared with the other conventional ships. As a result, the destruction of ship hull is occurred by the springing including to warping phenomena due to encounter waves. In this study, the solutions of hydrodynamic coefficients are obtained by solving the three dimensional source distribution method and the forward speed Green function representing a translating and pulsating source potential for infinite water depth is used to calculating the integral equation. The vessel is longitudinally divided into various sections and the added mass, wave damping and wave exciting forces of each section is calculated by integrating the dynamic pressures over the mean wetted section surface. The equations for six degree freedom of motions is obtained for each section in the frequency domain and stiffness matrix is calculated by Euler beam theory. The computations are carried out for very large ship and effects of bending and torsional ridigity on the wave frequency and angle are investigated.