• 한국산학기술학회논문지
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• 제22권5호
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• pp.371-378
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• 2021

본 연구는 여성노인을 대상으로 낙상예방을 위한 12주간 복합운동프로그램이 여성노인의 낙상관련 건강체력, 낙상위험도, 자세균형에 미치는 영향을 알아보기 위해 실시하였다. 본 연구의 목적을 달성하기 위해 연구대상자는 운동그룹 16명 통제그룹 16명으로 총 32명이 참여하였다. 운동그룹은 복합운동프로그램을 주 3회 60분씩 12주 동안 실시하였고 통제그룹은 같은 기간 동안 일상적인 생활을 하였다. 여성노인들의 낙상관련 건강체력은 노인체력검사(SFT: senior fitness test)중 동적평형성, 2분 동안 제자리걷기, 30초 동안 일어섰다 앉기 검사를 측정하였다. 여성노인들의 낙상위험도는 Tetrax장비로 측정하고 자세균형능력은 Spine Balance 3D를 이용하여 측정하였다. 본 연구의 자료처리는 SPSS/ver. 21을 이용하여 이원반복측정 변량분석(two-way ANOVA with repeated measures)을 실시하였고, 유의수준은 α=.05로 하였다. 본 연구결과 복합운동을 적용한 운동그룹은 동적평형성(p=.001), 2분 제자리걷기(p=.001), 30초 동안 일어섰다 앉기(p=.001), 낙상위험도(p=.002), 자세균형(p=.034)에서 통계적으로 유의한 차이가 보였지만 통제그룹은 통계적으로 유의한 차이를 보이지 않았다. 이상의 결과를 살펴보면 여성노인들의 12주간 복합운동프로그램 참여가 그들의 건강체력과 자세안정성을 향상시키고 낙상의 위험을 감소시킬 수 있을 것이다.

• 한국식품영양과학회지
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• 제46권5호
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• pp.616-621
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• 2017

시판 우리밀 강력분 밀가루의 품질 특성을 국내 대표적인 제빵용 수입밀 강력분 밀가루와 비교하였다. 우리밀 시판 강력분 제품은 수입밀 밀가루 제품과 비교해 수분 함량, 단백질 함량, 명도 및 색도가 낮게 나타났다. 용매보유능(SRC), gluten performance index(GPI), 수분흡수지수에서 시판 수입밀 강력분 밀가루가 높게 나타났으며, 수분용해지수는 우리밀 강력분 밀가루에서 높게 나타났다. 수입밀 강력분의 경우 전분 손상도와 관련된 SCSRC가 83.5%로 우리밀 강력분의 67.3~74.1%보다 높았으나, 글루텐 형성을 나타내는 LASRC가 낮게 나타났다. 최근 중요하게 인지되고 있는 GPI는 수입밀의 경우 0.65로 나타났으며, 우리밀은 0.5대의 수치를 보여 우리밀의 품질이 낮은 것으로 나타났다. 수분흡수지수에서는 수입밀이 더 많은 수분을 흡수하였으며, 그와 반대로 수분용해지수에서는 수입밀이 더 적은 양의 수용성 고형분이 용출되었다. Rapid visco analyzer를 통한 점도특성에서 전분의 노화 지표인 setback 수치가 수입밀과 우리밀 D3 시료에서 낮게 나타났다. 우리밀 시료 사이의 호화특성에서 유의적인 차이가 나타나, 같은 강력분 밀가루 내에서 점도 특성의 차이가 있었다. 밀가루 전분의 상변이 특성에서는 시판 강력분 수입밀 밀가루의 경우 상변화에 필요한 에너지가 6.2 J/g으로 우리밀의 6.67~7.13 J/g보다 낮았다. 밀가루 반죽 특성 분석 결과 수입밀의 경우 수분흡수율이 높았고, 반죽의 안정도 시간이 길게 나타났다. 우리밀 반죽의 저항도 및 신장성은 수입밀보다 낮았다.

• 디지털융복합연구
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• 제10권2호
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• pp.225-229
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• 2012

소형발전용 연료전지 시스템에 있어 개질장치는 탄화수소계의 연료를 수소가 풍부한 가스로 개질하여 주는 장치이다. 개질장치는 시스템 전체의 안정성과 성능의 관점에서 중요한 핵심 지표를 가지게 되는데 개질기의 핵심평가지표 중 가장 중요한 것은 배출가스 중의 CO농도이다. 시스템의 효율, 성능 및 안정성을 위하여 CO농도를 5ppm 이하로 관리되어야 한다. 본 연구에서는 개질기의 배출가스 내의 CO농도에 영향을 미치는 핵심인자를 도출한다. 개질기의 운전 및 설계에 있어 six-sigma 기법 중의 실험계획법을 도입하여 CO 농도에 영향을 미치는 핵심인자들을 도출해내고 도출된 인자들의 개선을 통하여 최적화된 운전조건을 제시하였다. 연료전지용 개질기에 있어서 가장 중요한 CO의 농도를 제어하기 위하여 도출된 인자들은 MTS, LTS, Prox와 같은 각 개질기내의 온도제어 및 그에 관한 결과로서의 CO 농도에 대한 최적 운전조건을 도출하였다.

• Journal of Acupuncture Research
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• 제31권4호
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• pp.45-55
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• 2014

Objectives : The main aim of this study was to assess the comparative efficiency of two preparation types of Hwangryunhaedok decoction(HRHD-D) using distilled and mixed extraction by measuring the index components and indicators of antioxidant and anti-inflammatory effects. Methods : The antioxidant activity was assessed by comparing distilled and mixed extractions of HRHD-D using an ELISA reader. The anti-inflammatory effect was determined by measuring NO amounts in RAW 264.7 cells. The contents were analyzed with high performance liquid chromatography-diode array detector(HPLC-DAD). Results : The electron donating ability of mixed and distilled extractions obtained with 500 ppm DPPH(1,1-diphenyl-2-picrylhydrazyl assay) solution were 57.8 % and 4.2 %, respectively. The total phenolic content of mixed extraction was 6.9 times that of distilled extraction and total flavonoid content was 51.5 times higher. The anti-inflammatory effect was assessed by NO measurement, and was found to increase significantly dependent on concentration in all mixed extract concentrations(25, 50, 100, 200, $400{\mu}g/mL$), but the difference in distilled extraction by concentration was only significant at 200 and $400{\mu}g/mL$. The HPLC analysis results of mixed extract of HRHD-D showed detection of all four main active constituents of HRHD-D. However, they were not detected in the distilled extract of HRHD-D. Conclusions : Mixed extraction with distillation added to decoction of HRHD-D showed better efficacy in antioxidant and anti-inflammatory effects, and ingredient quantities compared to distilled extraction. Further stability and clinical efficacy studies for standardization of mixed extractions are required.

• 한국인터넷방송통신학회논문지
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• 제14권5호
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• pp.237-242
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• 2014

이 논문은 발전소에서 설치 운전 중인 6.6kV 고전압 케이블이 시간에 따라 성능이 악화되는 현상의 추세를 결정하는 수명지수를 파악하기 위한 논문이다. 우리가 연구한 케이블 시스템은 설치 후 13 년 동안 운전하고 있다. 삼상전력에 연결되는 변류기, 온도센서 LPF 등을 이용한 측정장치를 개발하여 케이블의 절연저항 변화 특성을 해석하였다. 고전압 22kV 케이블과 비교하면 절연체의 두께가 더 두껍기 때문에 특성을 다르게 나타낸다. 동작시간이 경과함에 따라, 절연저항이 계속 감소하지 않음을 확인 하였다. 일정한 값으로 감소하다가 더 이상 감소하지 않고 상하진동하는 특성을 나타내었다. 지난 13 년 동안의 열화과정을 파악할 수 없었지만, 시스템이 안정 상태에서 동작을 하였다는 사실은 열화가 아직 발생하지 않았다는 의미이다. 이런 경우에는, 수명지수를 예측할 수 없기 때문에 케이블의 수명을 정량적으로 예측할 수 없음을 확인하였다.

• 한국자동차공학회논문집
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• 제19권6호
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• pp.30-36
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• 2011

The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situation including the worst case such as rollover, spin-out and so on. Although the known NHTSA Sine with dwell steering maneuvers are applied for the vehicle performance assessment, they aren't enough to estimate other possible worst case scenarios. Therefore, it is crucial for us to verify the various worst cases including the existing severe steering maneuvers. This paper includes useful worst case based upon the existing worst case scenarios mentioned above and worst case evaluation for vehicle dynamic controller in simulation basis and UCC HILS. The only human steering angle is selected as a design parameter here and optimized to maximize the index function to be expressed in terms of both yaw rate and side slip angle. The obtained scenarios were enough to generate the worst case to meet NHTSA worst case definition. It has been concluded that the new procedure in this paper is adequate to create other feasible worst case scenarios for a vehicle dynamic control system.

• 대한기계학회논문집B
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• 제22권9호
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• pp.1317-1324
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• 1998

In general, DI gasoline engine has the advantages of higher power output, higher thermal efficiency, higher EGR tolerance and lower emissions due to the operation characteristics of increased volumetric efficiency, compression ratio and ultra-lean combustion scheme. In order to apply the concept of stratified charge into direct injection gasoline engine, some kinds of methodologies have been adapted in various papers. In this study, a reflector was adapted around the injector nozzle to apply the concept of stratified charge combustion which leads the air-fuel mixture to be rich near spark plug. Therefore, the mixture near the spark plug is locally rich to ignite while the lean mixture is wholly introduced into the combustion chamber. The characteristics of combustion is analyzed with the variations of fuel injection pressure and load in a stratified -charge direct injection single cylinder gasoline engine. The obtained results are summarized as follows ; 1. The MBT spark timing approached to TDC with the increase of load on account of the increase of evaporation energy, but has little relation with fuel injection pressure. 2. The stratification effects are apparent with the increase of injection pressure. It is considered by the development of secondary diffusive combustion and the increase of heat release of same region, but proceed rapidly than diesel engine. Especially, in the case of high pressure injection (l70bar) and high load (3.0kgf m), the diffusive combustion parts are developed excessively and results in the decrease of peak pressure than in the case of middle load. 3. The index of engine stability, COVimep value, is drastically decreased with the increase of load. 4. To get better performance of DI gasoline engine development, staged optimizaion must be needed such as injection pressure, reflector, intake swirl, injection timing, chamber shape, ignition system and so on. In this study, the I50bar injection pressure is appeared as the optimum.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.179-190
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• 2010

This paper describes a new stochastic heuristic algorithm in engineering problem optimization especially in power system applications. An improved particle swarm optimization (PSO) called adaptive particle swarm optimization (APSO), mixed with simulated annealing (SA), is introduced and referred to as APSO-SA. This algorithm uses a novel PSO algorithm (APSO) to increase the convergence rate and incorporate the ability of SA to avoid being trapped in a local optimum. The APSO-SA algorithm efficiency is verified using some benchmark functions. This paper presents the application of APSO-SA to find the optimal location, type and size of flexible AC transmission system devices. Two types of FACTS devices, the thyristor controlled series capacitor (TCSC) and the static VAR compensator (SVC), are considered. The main objectives of the presented method are increasing the voltage stability index and over load factor, decreasing the cost of investment and total real power losses in the power system. In this regard, two cases are considered: single-type devices (same type of FACTS devices) and multi-type devices (combination of TCSC, SVC). Using the proposed method, the locations, type and sizes of FACTS devices are obtained to reach the optimal objective function. The APSO-SA is used to solve the above non.linear programming optimization problem for better accuracy and fast convergence and its results are compared with results of conventional PSO. The presented method expands the search space, improves performance and accelerates to the speed convergence, in comparison with the conventional PSO algorithm. The optimization results are compared with the standard PSO method. This comparison confirms the efficiency and validity of the proposed method. The proposed approach is examined and tested on IEEE 14 bus systems by MATLAB software. Numerical results demonstrate that the APSO-SA is fast and has a much lower computational cost.

• Journal of Korea Trade
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• 제23권7호
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• pp.147-155
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• 2019

Purpose - As the U.S.-China trade war has become considerably worse, the Chinese government is considering applying non-tariff barriers to trade, especially local contents rule. The main purpose of this research is to check whether it is suitable for Korean investors to invest in the current Chinese capital market. Design/methodology - In order to check the stability of the recent Chinese capital market, we investigated the behavior of foreign equity investment (including Korean equity investment) in the Chinese capital market after China announced the Shanghai-Hong Kong Stock Connect (SH-HK Connect). In this paper, we researched whether international portfolio investment would or would not contribute to an increase the volatility of an emerging market's stock market (Chinese capital market) when foreign investors make investment decisions based on the objective of short-term gains by rushing into countries whose markets are booming and fleeing from countries whose markets are falling. Findings - The empirical results indicate that foreign investors show strong, negative feedback trading behavior with regard to the stock index of the Shanghai Stock Exchange (SSE), and when the performance of foreign investors in the Chinese stock market was fairly good. Also, we found evidence that the behavior of foreign investors significantly decreased volatility in SSE stock returns. Consequently, the SH-HK Connect brought on a win-win effect for both the Chinese capital market and foreign investors. Originality/value - It appeared that the Chinese capital market was very suitable for Korean investors after the China's declaration of the SH-HK Connect. However, the win-win effect was brought on by the Chinese government's aggressive capital control but the capital controls could possibly cause financial turmoil in the Chinese capital market. Therefore, Chinese reform in industrial structure and the financial sector should keep pace with suitable capital control policies.

• 품질경영학회지
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• 제51권2호
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• pp.171-184
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• 2023

Purpose: First, this paper suggests an alternative approach to find optimal portfolio (stocks, bonds and ESG stocks) under the maximizing utility of investors. Second, we include ESG stocks in our optimal portfolio, and compare improvement of welfares in the case with and without ESG stocks in portfolio. Methods: Our main method of analysis follows Brennan et al(2002), designed under the continuous time framework. We assume that the dynamics of stock price follow the Geometric Brownian Motion (GBM) while the short rate have the Vasicek model. For the utility function of investors, we use the Power Utility Function, which commonly used in financial studies. The optimal portfolio and welfares are derived in the partial equilibrium. The parameters are estimated by using Kalman filter and ordinary least square method. Results: During the overall analysis period, the portfolio including ESG, did not show clear welfare improvement. In 2017, it has slightly exceeded this benchmark 1, showing the possibility of improvement, but the ESG stocks we selected have not strongly shown statistically significant welfare improvement results. This paper showed that the factors affecting optimal asset allocation and welfare improvement were different each other. We also found that the proportion of optimal asset allocation was affected by factors such as asset return, volatility, and inverse correlation between stocks and bonds, similar to traditional financial theory. Conclusion: The portfolio with ESG investment did not show significant results in welfare improvement is due to that 1) the KRX ESG Leaders 150 selected in our study is an index based on ESG integrated scores, which are designed to affect stability rather than profitability. And 2) Korea has a short history of ESG investment. During the limited analysis period, the performance of stock-related assets was inferior to bond assets at the time of the interest rate drop.