• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.187-196
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• 2003

Today, the Working Stress Rating (WSR) is being widely used for the capacity-rating and the safety assessment of railroad steel bridges. Since it cannot incorporate the uncertainties, several studies have been carried out in order to get over the incompleteness of the conventional capacity-rating and safety assessment. A system reliability-based equivalent capacity-rating method, which can evaluate the capacity of existing bridges, has been recently proposed. For more efficient reliability analysis, probabilistic parameters of the random variables in the limit-state models should be reasonably evaluated. Especially, uncertainties for live load effects must be realistically included. In this study, an improved limit-state model was used for the system reliability-based equivalent strength method. This model can incorporate the probabilistic parameters obtained from ambient measurement data. To demonstrate the applicability of the improved system reliability-based equivalent capacity rating method, this was applied to the existing steel plate girder bridge for comparison with the conventional capacity-rating and safety assessment.

• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.355-361
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• 2018

In this study, the dimensional stability and mechanical properties of bamboo fiber-based composites (BFBCs) were studied at two pressing manufacturing processes, i.e., hot- and cold- pressing, and were compared with three density parameters (1.0, 1.1, and $1.2kg/m^3$). Width swelling ratio (WSR), thickness swelling ratio (TSR), and water absorption ratio (WAR) were calculated for water immersions of 4 and 28 h. WSR, TSR, and WAR for specimens immersed for 28 h were higher than those for 4 h treatment, which shows that the immersion time has a significant influence on the dimensional stabilities of BFBCs. Moreover, the positive linear relations between density and dimensional were observed at both the pressing ways, indicating that the WSR, TSR, and WAR decreased with an increase in the density of BFBCs. The compressive strength, shear strength, modulus of rupture (MOR), and modulus of elasticity (MOE) were determined. The compressive strength, MOR, and MOE of hot-pressed specimens were significantly higher than those for the cold-pressed specimens, which are also directly proportional to density. Moreover, the samples with the highest density of $1.2kg/m^3$ performed high values on mechanical properties in both the manufacturing methods.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.125-137
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• 2008

Purpose: This study was designed as a epidemiologic study for determining priorities of nursing care in women with high risk groups of coronary heart disease(CHD) using risk factors. Method: Subjects were 1015 women who received health screenings at a hospital in Kyunggi, Korea, over one year period from January to December 2006. Results: The 37.9% of women had multiple risk factors for developing coronary heart disease. The most significant risk factors on CHD were the age older than 70 years (OR=11.45), the age between 60-69 (OR=4.65), the age between 50-59 (OR=3.20), having $HbA_1C$ over 7% (OR=2.38), high risk groups of L/H ratio (OR=1.98), and the waist to stature ratio (WSR) over 0.5 (OR=1.33). Conclusion: The findings suggest that women older than 50 years should be considered as an overt target population for CHD prevention, even in the absence of other risk factors. Also, $HbA_1C$ and WSR can be efficient indicators for CHD screening.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.103-108
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• 2020

RBC (red blood cell) deformability is one of factors inducing blood shear thinning effect. Reduction of RBC deformability increases blood viscosity in high shear region. In this study, 3D printed chip with proper distribution of wall shear rate (WSR) was proposed to measure RBC deformability of blood samples. To fabricate 3D printed chip, the design of 3D printed chip determined through numerical simulation was modified based on the resolution of the 3D printer. For the estimation of pressure drop in the 3D printed chip, two bypass outlets with low and high WSR are exposed to atmospheric pressure through the needles. By positioning the outlet of needles in the gravity direction, the formation of droplets at bypass outlets can be captured by smartphone. Through image processing and fast Fourier transform (FFT) analysis, the frequency of droplet formation was analyzed. Since the frequency of droplet formation is related with the pressure at bypass, high pressure drop caused by reduction of RBC deformability can be estimated by monitoring the formation of blood droplets using the smartphone.

• Korean journal of food and cookery science
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• v.31 no.5
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• pp.544-550
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• 2015

This study investigated the quality characteristics of English muffins made rice flour created using different grinding methods (DPR: powdered type rice flour by dry milling. DSR: soft type rice flour by dry milling. DHR: hard type rice flour by dry milling. WPR: powdered type rice flour by wet milling. WSR: soft type rice flour by wet milling. WHR: hard type rice flour by wet milling). The volume, volume expansion, and specific volume were the highest in WPR. The shape and cross section indicated that WPR, WSR and DPR were the best quality. The L value was the highest in DHR, the b value was the highest in DPR. Hardness, gumminess and chewiness were the lowest in WPR, and the highest in DHR. According to result of the sensory evaluation, the color, flavor, appearance, texture and overall acceptability were the highest in WPR, while the taste preference was the highest in WSR.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.81-89
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• 2013

Concerns have been raised over the impact of nano materials on soil and groundwater environment with the increasing attention to the potential applications of carbon nano materials in various fields. Particularly, carbon nano materials introduced into water environment readily make complexes with humic acid (HA) due to their hydrophobic nature, so there have been increasing numbers of studies on the interaction between HA and carbon nano materials. In this study, we investigated the solubility of HA and multiwalled carbon nanotubes (MWCNT) in three different surfactant solutions of sodium dodecyl sulfate (SDS), Brij 30 and Triton X-100, and evaluated whether the HA can be effectively desorbed from the surface of MWCNT by surfactant. The objective of this study was to determine the optimal adsorption condition for HA to MWCNT. Futhermore, sodium dodecyl sulfate (SDS), Brij 30, Triton X-100 were used to elucidate the effect of desorption and separation on adsorbed HA on MWCNT. As a result, HA solution with 12.7 mg of total organic carbon (TOC) and 5 mg of MWCNT showed the highest adsorption capacity at pH 3 reacted for 72 hrs. Weight solubilizing ratio (WSR) of surfactants on HA and MWCNT was calculated. HA had approximately 2 times lower adsorption capacity for the applied three surfactants compared to those of MWCNT, implying that the desorption of HA may occur from the HA/MWCNT complex. According to the results of adsorption isotherm and weight solubilizing ratio (WSR), the most effective surfactants was the SDS 1% soluiton, showing 53.63% desorption of HA at pH 3.

• Journal of Nutrition and Health
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• v.33 no.8
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• pp.873-881
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• 2000

Recent research reported health risks associate with high carbohydrates diets. Objectives of this study were to evaluate in a cross-sectional study if high carbohydrate diet is associated with coronary heart disease(CHD) risk factors: examined blood concnetration of triglyceride(TG), total cholesterol, high density lipoprotein cholesterol(HDL-C), plasma glucose, systolic blood pressure(BP), body mas index(BMI), wasit-hip ratio(WHR) and waist-stature ratio(WSR). Using the most recent US National Health and Nutrition Examination Survey(IIINHANES III) data, the nationally representative US population (3772 men, 4095 women of 25-64 years of age) was divided into low vs. high carbohydrate diet groups(below 40% vs. above 60% energy intake from cab carbohydrates) and compared by the CHD risk factors. Triglyceride was higher(p<0.001) in the high carbohydrate group, whereas high density-lipoprotein cholesterol(HDL-C)was lower(p<0.01) in the high carbohydrate diet group. In plasma glucose, there was no significant differences between high carbohydrate diet and low carbohydrate diet. In adiposity(BMI, WHR and WSR), it also showed no significant differences, After adjustment for age, ethnicity, alcohol and smoking in upper 60%-carbohydrate diet, Odds Ratio of TG and HDL-C were 1.42 and 1.23 in men and 1.22 and 1.17 in women. 50-60% carbohydrate diet was associated with decreased risk of CHD. Dietary guidelines for Koreans recommend 60-70% of total energy from carbohydrate, as Koreans traditionally consumed high carbohydrate diets. In a cross-sectional population of adults, diets containing 55-60% energy from carbohydrate were suggested as a dietary guideline of carbohydrate intake for Koreans. (Korean J Nutrition 33(8) : 873-881, 2000)

• Wind and Structures
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• v.12 no.4
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• pp.349-381
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• 2009

Since 1998, several institutions have deployed mobile instrumented towers to collect research-grade meteorological data from landfalling tropical cyclones. This study examines the wind flow characteristics from seven landfalling tropical cyclones using data collected from eight individual mobile tower deployments which occurred from 1998-2005. Gust factor, turbulence intensity, and integral scale statistics are inspected relative to changing surface roughness, mean wind speed and storm-relative position. Radar data, acquired from the National Weather Service (NWS) Weather Surveillance Radar - 1988 Doppler (WSR-88D) network, are examined to explore potential relationships with respect to radar reflectivity and precipitation structure (convective versus stratiform). The results indicate tropical cyclone wind flow characteristics are strongly influenced by the surrounding surface roughness (i.e., exposure) at each observation site, but some secondary storm dependencies are also documented.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.21-25
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• 2009

Extinguishing limits of laminar ethylene/oxygen flames in both normal and inverse co-flow jet burner have been determined experimentally and computationally. An inert gas($N_2$, Ar, $CO_2$) was added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the physical aspect of inert gases was main mechanism for flame blow-out as same as cup burner test, but the flow effect should be considered to determine the extinction concentration. The numerical prediction was performed with modified WSR model and the result was in good agreement with the measurements. The experimental and numerical methods could be used for the assessment of various flame suppression agents such as minimum extinguishing concentration.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.36-44
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• 2010

When multi-user MIMO (Multiple-Input Multiple-Output) systems utilize a sum-rate maximization (SRM) scheduler, the throughput of the systems can be enhanced. However, fairness problems may arise because users located near cell edge or experiencing poor channel conditions are less likely to be selected by the SRM scheduler. In this paper, a weighted sum-rate maximization (WSRM) scheduler is used to enhance the fairness performance of the MIMO systems. Closed-form expressions for the optimal transmit power allocation of WSRM and corresponding weighted sum-rate (WSR) are derived in the 6-sector collaborative transmission system. Using the derived results, we propose an algorithm which searches the optimal power allocation for WSRM in the 3-sector collaborative transmission system. Based on the derived closed-form expressions and the proposed algorithm, we perform computer simulations to compare performance of the WSRM scheduler and the SRM scheduler with respect to the sum-rate and the log-sum-of-average rates. We further verify that the WSRM scheduler efficiently improves fairness performance by showing the enhanced performance of average transmission rates in low percentile region.