• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권4호
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• pp.217-224
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• 2004

A novel anti-islanding method for the distributed power generation system (DPGS) is proposed in this paper. Three different islanding scenarios are explored and presented based on the analysis of real and reactive power mismatch. It is shown via investigation that islanding voltage is a function of real power alone, where its frequency is a function of both real and reactive power. Following this analysis, a robust anti-islanding algorithm is developed. The proposed algorithm continuously perturbs ($\pm$5%) the reactive power supplied by the DPGS while simultaneously monitoring the utility voltage and frequency. In the event of islanding, a measurable frequency deviation takes place, upon which the real power of the DPGS is further reduced to 80%. A drop in voltage positively confirms islanding and the DPGS is then safely disconnected. This method of control is shown to be robust: it is able to detect islanding under resonant loads and is also fast acting (operable in one cycle). Possible islanding conditions are simulated and verified through analysis. Experimental results on a 0.5kW fuel cell system connected to a utility grid are discussed.

• 소음진동
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• 제7권5호
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• pp.765-772
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• 1997

This paper presents the swing motion analysis of the container crane headblock with the passive control device using hydraulic motors and anti-swing ropes. The device hauls at the headblock to opposite direction of its swing motion using the tension difference between anti-swing ropes connected to the headblock. To consider this control mechanism, the headblock is modelled as the rigid bar suspended by two hoist ropes at the overhead trolley and its non-linear equation of motion is derived using Lagrange's equation. Some numerical experiments using the equation are carried out to investigate the swing motion characteristics of the headblock under the variation of geometric relation among the cargo handling components and to evaluate the performance of the anti-swing device.

• Mass Spectrometry Letters
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• 제14권2호
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• pp.25-35
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• 2023

Plants are a traditional source of many chemicals used as biochemical, flavors, food, color, and pharmaceuticals in various countries, especially India. Most herbal medicines and their derivatives are often made from crude extracts containing a complex mixture of various phytochemical chemical components (secondary metabolites of the plants). This study aimed to identify bioactive compounds from the different parts of the plant from the ethanolic extract of Gymnema sylvestre, Senna auriculata, and Cissus quadrangularis (leaves, flower, stem) by gas chromatography-mass spectroscopy (GC-MS). The gas chromatography - mass spectrometry analysis revealed the presence of various compounds like 3,4-dimethylcyclohexanol, hexanoic acid, D-mannose, and N-decanoic acid. Hence, the Gymnema sylvestre, Senna auriculata, and Cissus quadrangularis may have chemopreventive, anti-cancer, anti-microbial activity, antioxidant, anti-diabetic activity, anti-inflammatory, and antifungal due to the presence of secondary metabolites in the ethanolic extract. These phytochemicals are supported for traditional use in a variety of diseases.

• 동아시아식생활학회지
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• 제18권3호
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• pp.322-330
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• 2008

This study was performed to the possibility of developing anti-aging convenient food that is to Koreans' taste. Editor: this abstract appears to describe a study of public opinion and not related to the development of anti-aging convenient foods. In total, The 150 adults, living in Seoul (Korea), participated in this study in the capacity of subjects. Editor: You really have to mention the age-range of the subjects, as senility is an old age disease. In particular, you talk about the intention of subjects (discussed below) to buy anti-aging food products. This would be directly related to their age, as I assume that older people would be more concerned about senility that relatively younger subjects. They were randomly assigned to 25 groups. In result initial descriptive analysis revealed that, 82 percent of subjects awoke to were aware of senility, and the while 26.7 percent were seriously thought of it concerned. Furthermore, The 58.7 percent said that believed food has the possibility has a role in of controlling senility, and the while 64.0 percent said stated that senility may be controlled by eating constitutional foods. Further comparative analysis of In the case of the group of which members subjects have been who were trying to control senility revealed that their, the reliance on food general and constitutional food was significantly higher than those who have not tried to do so did nothing. The From the 61.3 percent have been of subject who were trying to control senility, from among them, the 74.0 percent and the 22.7 percent were relied on physical taking exercises and anti-aging foods, respectively. Likewise, it was ascertained When asked whether subjects intend to purchase anti-aging convenient food if it was is developed. The 67.3 percent and the 72.7 percent indicated their intentionded to purchase the normal product and constitutional products, respectively. Resultantly, anti-aging convenient food was in demand to some extent. Given that anti-aging products are in high demand, In such a case, senile severity (p<0.05), anti-aging possibility in constitutional foods (p<0.001) and anti-aging action (p<0.001) are regarded as variables in the purchase of the normal products. In the case of relation to constitutional products, anti-aging possibility in constitutional food (p<0.001) and anti-aging action (p<0.001) were regarded as variables.

• 한방안이비인후피부과학회지
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• 제34권4호
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• pp.1-11
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• 2021

Objectives : The aim of this study was to investigated the anti-aging and anti-wrinkles effects of the pinus koreaiensis seed(PKS) oil. Methods : The anti-oxidant effect was performed by beta-carotene bleaching assay and the intracellular proteome was analyzed expression of each 15 proteins by 2-D electrophoresis. And fatty acid was analysed by gas chromatography. Anti-wrinkle effect was analyzing human skin by the PRIMOS system. Results : Fatty acid analysis of PKS oil has shown oleic acid was 49.7% and linoleic acid was 34.1%. And the antioxidant effect was about 125% compared with alpha-tocoperol(0.1%) by beta carotene bleaching assay. In 2D PAGE analysis, fifteen protein changes in five mechanisms which was collagen synthesis pathway, MMPs, ECM-cell interaction, cytokine, antioxidant enzymes were analyzed. In case of anti-wrinkle effect was proved in vivo by analyzing human skin by the PRIMOS system. The analysis results of eye wrinkles for 4 weeks showed an improvement effect of over 6%. Conclusions : In this study, the amount of protein change in the five mechanism through the cell experiment and the skin anti wrinkle efficacy by the human in vivo test were investigated. As a result pinus koreaiensis seed oil by supercritical extraction could be used as a anti-aging and anti-wrinkle substance for the skin.

• Journal of Positioning, Navigation, and Timing
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• 제8권1호
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• pp.19-29
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• 2019

This paper analyzes the design factors for GNSS anti-jamming receiver system in which the adaptive beamforming algorithm is applied in GNSS receiver system. The design analysis factors used in this paper are divided into three: antenna, beamforming algorithm, and operation environment. This paper analyzes the above three factors and presents numerical simulation results on antenna and beamforming algorithm.

• 한국위성정보통신학회논문지
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• 제10권4호
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• pp.46-51
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• 2015

본 논문에서는 항재밍 GPS(Global Positioning System) 시스템을 위한 선형 어레이 안테나(linear array antenna) 시뮬레이터(simulator)를 설계하고 시뮬레이션을 통해 다양한 성능 평가를 수행하였다. 먼저 GPS 위성의 신호 구조 분석을 통해 모의 송신신호를 발생시키고, 선형 어레이 안테나 고려시 잡음 환경하에서의 어레이 수에 따른 SNR(Signal to Noise power Ratio) 성능을 분석하였다. 또한 MMSE(Minimum Mean Square Error) 방식의 신호처리 시스템을 통해 재머(jammer) 수에 따른 항재밍 빔패턴(beam pattern) 성능을 분석하였으며, 안테나 칼리브레이션(calibration) 문제를 고려하여 어레이간 지연이 존재하는 경우에서의 항재밍 성능을 분석하였다.

• 국제강구조저널
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• 제18권5호
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• pp.1801-1817
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• 2018

This paper presents the numerical parametric analysis on the loading capacity of Channel purlins with screw-fastened sheeting, in which the effects of anti-sag bar and corrugated steel sheet on the ultimate capacity are studied. Results show that the setup of anti-sag bars can reduce the deformations and improve the ultimate capacity of C purlins. The traditional method of setting the anti-sag bars in the middle of the web is favorable. The changing of sheeting type, sheeting thickness and rib spacing has significant effects on the ultimate capacity of C purlins without anti-sag bars, compared with those with anti-sag bars. The proposed design formulas are relatively consistent with the calculations of EN 1993-1-3:2006, which is different from those of GB 50018-2002.

• 대한조선학회논문집
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• 제50권6호
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• pp.450-457
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• 2013

For the design guide of a vessel operating in cold region, numerical analysis was carried out to evaluate the weather-tight door which installed the heating cables by using ANSYS 13.0 Transient Thermal. The numerical analysis was performed by considering Advection-Diffusion equation. This study based on the experimental results of 'A study on Anti-Icing Technique for Weather-Tight Door of Ice-Strengthened Vessels'(Jeong, et al., 2011a) in KIOST. For validation of the numerical analysis results, the cold chamber experimental data measured by the heat sensors in certain location of the weather-tight door was used. The external environmental temperature which varies from $5^{\circ}C$ to $-55^{\circ}C$ was considered in numerical analysis. Also three different heating cables which have the heat capacity of 33W/m, 45W/m and 66W/m were adapted for the design parameters to be the most efficient and guidelines for anti-icing design of the weather tight door.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.850-853
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• 2008

In the motorized retractor of the smart seat belt system, anti-overload clutch is a very important element to prevent the excessive belt tensional force. Anti-overload clutch is the essential device to protect drivers from chest damage by the excessive belt tension. It generates slipping motion under excessive webbing moment and the belt tensional force is limited below critical value. In this study, slipping mechanism in the antioverload clutch is investigated by analysis and experiment. On the prototype model, finite element analysis is performed to identify the slipping condition and to determine the critical load. Analysis result is compared with the experimental result and the validity of the analysis model is verified. The purpose of the study is to provide the analytical background for the systematic design of the anti-overload clutch mechanism.