• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4529-4536
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• 2010

This paper develops an interconnection test devices for photovoltaic(PV) systems composed of distribution system simulator, PV systems simulator and control and monitoring systems using the LabVIEW S/W, and simulates the customer voltage characteristics considering the 3 parameters on the introduction capacity for PV systems, system configuration and load factor. This paper also proposes a new calculation algorithm for voltage profile to make a comparison between calculation values and test device values. The results show that the test results for the normal operation characteristics of PV systems is very practical and effective.

• Anxiety and mood
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• v.7 no.1
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• pp.34-39
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• 2011

Objectives : An early age at onset of obsessive compulsive symptoms in family studies has been strongly associated with a more familial form of obsessive compulsive disorder (OCD). Further, many reports have suggested that early- and late- onset OCD represent separate subtypes of the disorder. The aim of this study was to investigate the associations between the glutamate receptor, the ionotropic, n-methyl-d-aspartate (NMDA) subunit 2B gene (GRIN2B) polymorphisms, and onset of OCD in the Korean population. Methods : We recruited 109 OCD patients and classified them into early- (age of onset <18 years) and late-onset groups (age of onset${\geq}$18). Genomic DNA was extracted from their blood after which the genotypes and allelic frequencies of the two GRIN2B polymorphisms (5072T/G and 5988T/C) were compared in the two groups. We also compared genetic data between child- (age of onset${\leq}$15) and adult-onset groups (age of onset${\geq}$19) using the same protocol. Results : There were no significant differences between the early- and late-onset groups with respect to genotype. Moreover, we could not find any differences in genotype frequencies between child and adult-onset groups. Conclusions : Our study suggested that GRIN2B polymorphisms (5072T/G and 5988T/C) do not affect the onset of OCD in Koreans. However, this finding has resulted from a preliminary study and thus, further study is required.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.53-63
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• 2016

This study aims to verify the feasibility of design by developing pressure flow-controlled swash plate type pump with the use of SimulationX, a computer analysis program. Developing analysis model based on design drawing data has a cost-saving effect because it is possible to figure out the effectiveness of design through the work and it never falls into repeated inaccuracies in the production process. Analysis model is developed in the following order. First, the structure of each part such as valve and rotating unit which have dynamic factor is analyzed and the modeling of single component is carried out, reflecting drawing data. Second, the modeling of pump assembly is carried out with the combination of each analysis model and a work is conducted to determine whether the modeling can perform pressure flow control function according to load condition smoothly based on design intent. At the end of the modeling process, the feasibility of design is verified by showing the parts which are moving as expected mechanism.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.31-42
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• 2016

This study aims to identify the core technology for the automatic impact of the auto-sensing breaker that is one of the construction machinery which do not have a notable development success case yet in Korea. The study has been carried out as follows. Firstly, an analysis model was developed after determining the interconnection of pressure receiving area, opening area and port. And then, a simulation of situation that hard rock and soft rock are mixed was carried out to verify if it is possible to switch between long impact mode and short impact mode continuously. Lastly, the dynamic behavior of automatic control valve induced by the change of impact mode was analyzed based on the analysis result to decipher the core principle of automatic impact control.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.22-27
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• 2019

Nail polish is used to decorate nail beautifully however, it contains lots of toxic materials. Generally, Nail polish consists of film-forming agent, colorant, solvent, surfactant and stabilizer. In this study, to replace toxic chemicals to low irritative, eco-friendly ingredients, we prepared 4 kinds of nail polish and tested safety, stability and performance. Nail polish including shellac/gelatin showed best performance in water-resistance, friability and drying time. When cell toxicity test is done by MTT assay, shellac-gelatin nail polish showed over 70% cell viability at $1,000{\mu}g/mL$ whereas control nail polish in market showed 50% cell viability. At 4 weeks temperature stability test, color was stable at low temperature however it needs formulation improvement at higher temperature.

• The Journal of Korean Institute of Next Generation Computing
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• v.14 no.6
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• pp.66-74
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• 2018

Recently, there has been active studies on hand gesture recognition to increase immersion and provide user-friendly interaction in a virtual reality environment. However, most studies require specialized sensors or equipment, or show low recognition rates. This paper proposes a hand gesture recognition method using Deep Learning technology without separate sensors or equipment other than camera to recognize static and dynamic hand gestures. First, a series of hand gesture input images are converted into high-frequency images, then each of the hand gestures RGB images and their high-frequency images is learned through the DenseNet three-dimensional Convolutional Neural Network. Experimental results on 6 static hand gestures and 9 dynamic hand gestures showed an average of 92.6% recognition rate and increased 4.6% compared to previous DenseNet. The 3D defense game was implemented to verify the results of our study, and an average speed of 30 ms of gesture recognition was found to be available as a real-time user interface for virtual reality applications.

• Korean Chemical Engineering Research
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• v.62 no.2
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• pp.142-146
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• 2024

There is growing interest in natural cosmetic ingredients as natural cosmetics become popular. As a part of effort to look for natureal cosmetic agent, seaweed Sargassums were tested for functional cosmetic agents. Effective materials were extracted from Sargassum coreanum. Sargassum hemiphyllum, and Sargassum patens by simple hot water extraction. Antioxidation, whitening, anti-wrinkle, UV absorption and anti-inflammation effects were studied for functional cosmetic agents. Sargassum extracts indicated excellent cell viability, strong anti-oxidation effect by DPPH radical scavenging activity and showed significant whitening effect from tyrosinase inhibition. However, effects of antiwrinkle, UV absorption and anti-inflammation were negligible. In conclusion, Sargassum coreanum extracts showed good possibility for anti-oxidation and whitening cosmetic agent.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.662-671
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• 2020

Recently, for the purposes of reducing carbon dioxide(CO₂) emissions in the island area, countermeasures to decrease the operation rate of diesel generator(DG) and to increase one of renewable energy sources(RES) is being studied. In particular, the demonstration and installation of stand-alone micro-grid(MG) system which is composed of DG, RES and energy storage system(ESS) has been implemented in some island areas such as Gapa-do, Gasa-do and Ulleung-do island. However, many power quality(PQ) problems may be occurred due to an intermittent output of RES including photovoltaic(PV) system and wind power(WP) system in a normal operating of constant voltage & constant frequency(CVCF) inverter-based MG system. Therefore, this paper presents a modeling of the 30kW scale MG system using PSCAD/EMTDC, and also implements a 30kW scale CVCF inverter-based MG system as test devices to analyze normal operating characteristics of MG system. From the simulation and test results, it is confirmed that the proposed methods are useful and practical tools to improve PQ problems such as under-voltage, over-voltage and unbalanced load in CVCF inverter-based MG system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.42-51
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• 2017

This paper deals with the power supply facility providing wireless power transmission for a type of electric vehicles called the on-line electric vehicle(OLEV) and proposes optimal protection coordination methods which analyze the faultsin the 60Hz and 20kHz bands using PSCAD/EMTDC, which is the typical commercial software for the distribution system. The simulation results show that the proposed methods can reduce the fault current by introducing an NGR (Neutral Ground Resistor) in the 60Hz band and prevent the malfunctioning of the protection device by installing a CT in the neutral wire in the 20kHz band when a ground fault occurs.

• Journal of the Korea Convergence Society
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• v.2 no.4
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• pp.29-37
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• 2011

Dispersed generation (DG) such as wind power (WP) and Photovoltaic systems (PV) that has been promoted at the national level recently is mainly being introduced into distribution systems adjacent to consumers because it is generation on a small scale when compared to current generation. Due to its characteristics, DG can be operated by interconnection with distribution systems to present security of more stable power and efficient use of power facilities and resources. Problems on protection coordination of distribution systems by reverse flow of DG can roughly be divided into three possibilities: excess in rated breaking capacity (12.5KA) of protective devices by a fault in DG current supply, failure to operate protective devices by an apparent effect that can occur by reduction in impedance parallel circuit fault current due to interconnection of DG, and malfunction of protective devices by interconnection transformer connection type. The purpose of this study is to analyze problems in protection coordination that can occur when DG is operated by interconnection with distribution systems by conducting modeling and simulations by using theoretical symmetrical components and MATLAB/SIMULINK to present methods to improve such problems.