• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.254-259
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• 2014

In this paper, we describe construction of a wind stabilization demo-site and effects of output power control of wind turbines for suppression of ramp rate using ESS (Energy Storage System). It is difficult to control the output power of distributed generator such as wind turbine which of variation is very large. If the large capacity wind farm be interconnected into power system may cause blackout due to Power Quality. For these reasons, the international standards such as Grid-Code is limited to less than 10 [%/min] of renewable energy ramp rate. The case of Korea, government actively conducts propagating large-scale renewable energy for green growth policy, to interconnecting more renewable energy into power system is necessary for stabilization technology. For these reasons, the POSCO consortium has constructed a wind stabilization demo-site that is configured as 500 [kWh] battery energy storage systems can output up to 3 [C-Rate] and two wind turbines rated 750 [kW]. In POSCO consortium, which implements various methods stabilizing output power of wind turbine such as smoothing, section firming and ramp control, we derive the results of long-term demonstration that can be controlled to satisfy to the international standard about ramp rate [%/kW] of wind turbine output power.

• Journal of Environmental Health Sciences
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• v.41 no.4
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• pp.223-230
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• 2015

Objectives: There is considerable evidence that polluted ambient air contributes to the risk of cardiovascular morbidity and mortality. Heart rate variability (HRV) is defined as the variation in heartbeat intervals and has been reported as a biological marker of cardiovascular disease. This article reviews the existing literature in order to examine the association between air pollution and HRV. Methods: Literature was searched using Web of Science with the key words of "air pollution", "heart rate variability" and other related terms. A total of 156 articles were listed. For review, 21 of those listed publications were chosen after excluding studies regarding chamber studies, occupational environment, secondhand smoke and automobile exhaust. Results: Research methods employed in the publications were classified by type of participants (elderly/adult), air pollution monitoring (ambient/personal) and HRV monitoring (continuous/spot). Among HRV parameters, power in the low frequency range (LF), power in the high frequency range (HF) and standard deviation of all NN intervals (SDNN) were all associated with air pollutants. The chosen studies were mostly based on elderly populations. In studies based on continuous HRV monitoring, LF and SDNN significantly decreased when $PM_{2.5}$ exposure increased. Conclusion: Continuous HRV monitoring combined with personal exposure monitoring has been one of the most common study methods in recent publications. We expect that this review will be useful for the study of the association between air pollution and cardiovascular effects using HRV.

• Journal of the Korean Society of Costume
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• v.51 no.7
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• pp.147-165
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• 2001

The objective of this study was to develop the Jeogori Pattern for 9 to 10 year-old boys To determine the measurement items for the Jeogori Pattern making, applied factor analysis, correlation analysis and regression analysis to the 37 measurement items of the 9 to 10 year-old boys classified as a standard somatotype. To understand the shape and variation of the body surface, analyzed the replica of the upper body surface that was obtained by the method of using surgical tape. Be based on the results of the above studies, designed the Jeogori Pattern. The designed pattern was evaluated by the sensory test. The drafting methods of Jeogori Pattern obtained are as follows. $\circled1$ The measurement items are Bust Girth, Center Back Waist Length, Neck Width, and Hwajang Length. $\circled2$ Jeogori Length Center Back Waist Length$\times$4/3 $\circled3$ Front Body Girth(1/2) : B/2 + 1.5cm Back Body Girth(1/2) : B/2 + 3.5cm $\circled4$ Jin-Dong : B/4 + 3cm $\circled5$ Back Godae Width(1/2) : Neck Width/2 + 1.7cm Front Godae Width(l/2) : Back Godae Width(1/2) - 2cm $\circled6$Back Godae Point is 1.5cm higher than shoulder line, and Front Godae Point is 1.5cm lower than shoulder line. $\circled7$ Back Godae Depth: 1.2cm + 1.5cm = 2.7cm The Jeogori Pattern designed by the above method Is as (fig. 8) The results of the sensory test of the new pattern are as fellows. Except for 2 items, every mark of 24 test items has over 5.0 point and a total average mark is 5.25 point. Witch is a good mark. Therefore the new pattern is valid. Especially, the parts of Git, sleeves and back face have a high mark, so the appearances of those parts are excellent.

• Computers and Concrete
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• v.7 no.3
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• pp.203-220
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• 2010

In the present study, exterior beam-column sub-assemblage from a regular reinforced concrete (RC) building has been considered. Two different types of beam-column sub-assemblages from existing RC building have been considered, i.e., gravity load designed ('GLD'), and seismically designed but without any ductile detailing ('NonDuctile'). Hence, both the cases represent the under-designed structure at different time frame span before the introduction of ductile detailing. For designing 'NonDuctile' structure, Eurocode and Indian Standard were considered. Non-linear finite element (FE) program has been employed for analysing the sub-assemblages under cyclic loading. FE models were developed using quadratic concrete brick elements with embedded truss elements to represent reinforcements. It has been found that the results obtained from the numerical analysis are well corroborated with that of experimental results. Using the validated numerical models, it was proposed to correlate the energy dissipation from numerical analysis to that from experimental analysis. Numerical models would be helpful in practice to evaluate the seismic performance of the critical sub-assemblages prior to design decisions. Further, using the numerical studies, performance of the sub-assemblages with variation of axial load ratios (ratio is defined by applied axial load divided by axial strength) has been studied since many researchers have brought out inconsistent observations on role of axial load in changing strength and energy dissipation under cyclic load.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.237-250
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• 2011

The train transportation has a lot of advantages-energy efficiency is high, it is eco-friendly, safety is better than normal roads and it is possible for people to arrive on time. In these days, the valuation of ride comfort, which is only limited to road transportation, is newly recognized in order to having competitiveness from other transportation. Especially, in the development of the Korean high-speed railroad business, the ride comfort enhancement of train is very important problem to be solved. Currently, there are international standards of ride comfort such as UIC13, ISO2631. In Korea case, although it has own standard like KS R9216, it mainly depends on the physical parameter such as vibration and noise. So recently, in the valuation of ride comfort, the movements of living parameter technique introduction are increasing on the base of Japan and many developed countries of Europe techniques. Presently, the method of train ride comfort is mainly based of vibration, that is, mechanical parameter adding selection of variable acceleration and noise. This paper would like to show biological parameter; heart rate and blood pressure variation. This method is more direct, based on human body response, than mechanical parameter method. In this experiment, the variability of heart rate and blood pressure of passengers according to tilting angle change of Train, the Korean tilting train, we are supposed to know that the extent of tilting on the simulation has influence on variability of heart rate and blood pressure, which are living parameter of heart's blood.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.112-123
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• 2017

The accurate forecasting of the public transportation's transit and arrival time has become increasingly important as more people use buses and subways instead of personal vehicles under the government's public transportation promotion policy. Using bus management system (BMS) data, which provide information on the real-time bus location, operation interval, and operation history, it is now possible to analyze the bus schedule reliability. However, the punctuality should always be considered together with the operation safety. Therefore, this study suggests a new methodology to secure both reliability and safety using the BMS data. Unlike other studies, we calculated the bus travel time between two bus stops by dividing the total travel length into 6 sections using 5 different measuring points. In addition, the optimal travel time for each bus route was proposed by analyzing the mean, standard deviation and coefficient of variation of the each section's measurement. This will ensure the reliability, safety and mobility of the bus operation.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.137-144
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• 2009

In this study, quantitative and pattern recognition analyses for the quality evaluation of Herba Epimedii using HPLC was developed. For quantitative analysis, five major bioactive constituents, hyperin, epimedin A, epimedin B, epimedin C, and icariin were determined. Analysis was carried out on Capcell pak $C_{18}$ column ($250{\time}4.6$ mm, 5 ${\mu}m$) with a mobile phase of mixture of acetonitrile and 0.1% formic acid, using UV detection at 270 nm. The linear behavior was observed over the investigated concentration range (2-50 ${\mu}g/mL;\;r_2\;>$ 0.99) for all analytes. The intraand inter-day precisions were lower than 4.3% (as a relative standard deviation, RSD) and accuracies between 95.1% and 104.4%. The HPLC analytical method for pattern recognition analysis was validated by repeated analysis of one reference sample. The RSD of intra- and inter-day variation of relative retention time (RRT) and relative peak area (RPA) of the 12 selected common peaks were below 0.8% and 4.7%, respectively. The developed methods were applied to analysis of twenty Herba Epimedii extract samples. Contents of hyperin, epimedin A, epimedin B, epimedin C, and icariin were calculated to be 0$\sim$0.79, 0.69$\sim$1.91, 0.93$\sim$9.58, 0.65$\sim$3.05, and 2.43$\sim$11.8 mg/g dried plant. Principal component analysis (PCA) showed that most samples were clustered together with the reference samples but several apart from the main cluster in the PC score plot, indicating differences in overall chemical composition between two clusters. The present study suggests that quantitative determination of marker compounds combined with pattern-recognition method can provide a comprehensive approach for the quality assessment of herbal medicines.

• Survey Research
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• v.11 no.1
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• pp.123-144
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• 2010

In new sample design for Korea Housing Survey to research about housing policy, total strata are forty five because individual results of sixteen regions are estimated. The sample size is determined by sample errors of several variables which are the living area, family income, householder income, and living expenses. The sample size of each region is determined by relative standard error of existing result, and the strata sample size is to use the square root proportion allocation. Enumeration districts are sampled by the probability proportion to size systematic sampling in proportion to the enumeration district size, and the systemic sampling to use assortment characteristics. We considered a new apartment complex because of variation reflections which are rebuilder and redevelopment of houses. To get estimators of mean and variance, we used the design weighting, non-response adjusting, and post-stratification. In order to consider estimation efficiency, we calculate the design effect using estimators of variance.

• Wind and Structures
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• v.25 no.6
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• pp.507-535
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• 2017

In the strong wind shutdown state, the blade position significantly affects the streaming behavior and stability performance of wind turbine towers. By selecting the 3M horizontal axis wind turbine independently developed by Nanjing University of Aeronautics and Astronautics as the research object, the CFD method was adopted to simulate the flow field of the tower-blade system at eight shutdown positions within a single rotation period of blades. The effectiveness of the simulation method was validated by comparing the simulation results with standard curves. In addition, the dynamic property, aerostatic response, buckling stability and ultimate bearing capacity of the wind turbine system at different shutdown positions were calculated by using the finite element method. On this basis, the influence regularity of blade shutdown position on the wind-induced response and stability performance of wind turbine systems was derived, with the most unfavorable working conditions of wind-induced buckling failure of this type of wind turbines concluded. The research results implied that within a rotation period of the wind turbine blade, when the blade completely overlaps the tower (Working condition 1), the aerodynamic performance of the system is the poorest while the aerostatic response is relatively small. Since the influence of the structure's geometrical nonlinearity on the system wind-induced response is small, the maximum displacement only has a discrepancy of 0.04. With the blade rotating clockwise, its wind-induced stability performance presents a variation tendency of first-increase-then-decrease. Under Working condition 3, the critical instability wind speed reaches its maximum value, while the critical instability wind speed under Working condition 6 is the smallest. At the same time, the coupling effect between tower and blade leads to a reverse effect which can significantly improve the ultimate bearing capacity of the system. With the reduction of the area of tower shielded by blades, this reverse effect becomes more obvious.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.218-227
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• 2014

In this paper, it performed to the elastic-plastic large deflection series analysis using the experimental model and predicted a failure mode and ultimate strength. The collapse mode of numerical analysis model is formed a plastic hinge on loaded flange and consistent with the collapse mode of experimental model. Also, The yield line is formed in the web could observed that have occurred the crippling collapse mode and the ultimate loads of the experimental model and numerical analysis model have maintained linearly Means 1.07, Standard deviation 0.04, Coefficient of variation(COV) 0.04 and the result of ultimate loads have appeared approximately 8% error rate. it was found that very satisfied to the experimental results and the applied rules. if it is considered to be maintain a reasonable safety level, it is possible to predict the failure modes of aluminium alloy plate girders and ultimate loads.