• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.518-521
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• 1989

Recently, PWM cycloconverters that are frequency conversion system have been studied for eliminating do links of conventional converter and inverter systems. A new real-time method for generating PWM patterns is proposed in this paper. This method realizes sinusoidal input and output currents, controllable input displacement factor regardless of load power factor, and maximum output voltage range. Finally, feasibility of the proposed method is confirmed by simulation and experiments.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.6 no.1
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• pp.44-50
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• 2003

If the accelerometers are used in measuring the response, the absolute values of the velocity and displacement are not usually obtainable because their initial values are not accounted for in the integration of the acceleration response. A new dynamic response conversion algorithm of both the time domain and the frequency domain is proposed for the problem in estimating the displacement data by defining the transformed responses. In this algorithm, the displacement response can be obtained from the measured acceleration records by integration without requiring the knowledge of the initial velocity and displacement information. The applicability of the technique is tested by an example problem using the real bridge's superstructure under several cases of moving load. In the response conversion procedure of the frequency domain, the identified response according to the frequency can be estimated by changing over the limits of integration. If the reliability of the identified responses is ensured, it is expected that the proposed method for estimating the impact factor can be useful in the bridge's dynamic test. This method can be useful in those practical cases when the direct measurement of the displacement is difficult as in the dynamic studies of huge structure.

• Korean Institute of Interior Design Journal
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• v.16 no.2 s.61
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• pp.40-50
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• 2007

This study started from my concern over maintenance and renewal of existing buildings and other seriously damaged Modern Architecture under the urban development. Above all, we must face up to reality of an increasing need of renovation of old buildings that are in its physical, social, and economical decrepitude. Currently, 25% of total buildings come under renovation period within 20 years, which means that we do not have enough time to decide the destiny of old buildings. In the city, there has been endless controversy over conversation and development. Recently the Cultural property Registration System made it possible a positive usage of non-designated cultural property with historical value. This very useful system renewed our perception on Modern Architecture as cultural property and also triggered peoples' interest in recreating new value beyond economical one. So we really need a balanced view that can bring into both growth of contemporary city and renewal use of Modern Architecture. Here, in this study I tried to solve that problem with Conversion Design and define what a realistic design way for them is. To get more reasonable result, I chose a factor analysis for 20 conversion projects in Japanese Modern Architecture. Conversion Design is a proper way to restore the identity of old buildings and the most effective way to sustainable use of Modern Architecture.

• Journal of Environmental Science International
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• v.26 no.9
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• pp.999-1011
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• 2017

In this study, the Chiu-2D velocity-flow rate distribution based on theoretical background of the entropy probability method was applied to actual ADCP measurement data of Gangjung Stream in Jeju from July 2011 to June 2015 to predict the parameter that take part in velocity distribution of the stream. In addition, surface velocity measured by SIV (Surface Image Velocimeter) was applied to the predicted parameter to calculate discharge. Calculated discharge was compared with observed discharge of ADCP observed during the same time to analyze propriety and applicability of depth of water velocity average conversion factor. To check applicability of the predicted stream parameter, surface velocity and discharge were calculated using SIV and compared with velocity and flow based on ADCP. Discharge calculated by applying velocity factor of SIV to the Chiu-2D velocity-flow rate distribution and discharge based on depth of water velocity average conversion factor of 0.85 were $0.7171m^3/sec$ and $0.5758m^3/sec$, respectively. Their error rates compared to average ADCP discharge of $0.6664m^3/sec$ were respectively 7.63% and 13.64%. Discharge based on the Chiu-2D velocity-flow distribution showed lower error rate compared to discharge based on depth of water velocity average conversion factor of 0.85.

• Current Photovoltaic Research
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• v.4 no.2
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• pp.48-53
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• 2016

We report the effect of physical load on the stability of organic solar cells under physical loads. The active layers in organic solar cells were fabricated with bulk heterojunction films (BHJ) films of poly (3-hexylthiophene) and phenyl-$C_{61}$-butyric methyl ester. The loading time was varied up to 60 s by keeping the physical load constant. Results showed that the open circuit voltage was not influenced by the physical load but other solar cell parameters were sensitive to the loading time. The fill factor was very slightly increased at 15 s, while short circuit current density was well kept for 30 s. The power conversion efficiency was reasonably maintained for 45 s but became significantly decreased by the continuous loading for 60 s.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.514-517
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• 2008

Water gas shift(WGS) is an important step in fuel process for fuel cells, and improperness of commercial WGS catalysts for use in fuel cell systems has prompted numerous researches on noble metal catalysts. A selected noble metal catalyst for water gas shift reaction(WGS) was prepared with various metal loadings. The prepared catalysts were tested under two feeding conditions. At moderate residence time, carbon monoxide conversion was much higher on the noble metal catalysts as compared to commercial high-temperature shift catalyst. Effects of metal loading were examined by activity tests at short residence time. Higher metal loading effected higher reaction rate. The kinetic data was fitted to simple reaction equations and effectiveness factor was estimated. The results suggest the necessity of a structural design for the highly active noble metal catalysts.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.252-256
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• 2007

A series of spherical porous carbons were prepared via resorcinol-formaldehyde (RF) sol-gel polymerization in the presence of cationic surfactant (CTAB, cetyltrimethylammonium bromide), wherein the carbon sphere size was controlled by varying the CTAB introduction time after a pre-determined period of addition reaction (termed as "pre-curing"). The sphere size gradually decreases with an increase in the pre-curing time within the range of 30-150 nm. The carbons possess two types of pores; one inside carbon spheres (intra-particle pores) and the other at the interstitial sites made by carbon spheres (inter-particle pores). Of the two, the surface exposed on the former was dominant to determine the electric double-layer capacitor (EDLC) performance of porous carbons. As the intra-particle pores were generated inside RF gel spheres by gasification, the pore diameter was similar for all these carbons, thereby the pore length turned out to be a decisive factor controlling the EDLC performance. The charge-discharge voltage profiles and complex capacitance analysis consistently illustrate that the smaller-sized RF carbons deliver a better rate capability, which must be the direct result of facilitated ion penetration into shorter pores.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.403-406
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• 1998

There are two cases of error occurrence of STT(Smart Temperature Transmitter). One is that because of unstable reference voltage, data from A/D converter is not reliable. The other is that because of change of room temperature, this change affects conversion of A/D converter. In this paper, we show algorithms be adapted to STT for reliable conversion of A/D converter through a experiment and compensation for temperature change. In a experiment, we collect data from reference voltage and ground then calculate nominal value of these at constant temperature during A/D converter initialization or at any conversion time. Algorithm for compensation for unstable reference voltage calculates a correction factor and adapts it to compensation for malfunction of A/D converter. Algorithm for compensation for variation of room temperature is come from linearization of thermistor but is adapted to zener diode, not thermistor, therefor we have less effort for compensation for temperature and have a idea that it can be adapted to A/D converter system.

• Korean Journal of Adult Nursing
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• v.25 no.3
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• pp.275-288
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• 2013

Purpose: The purpose of this study was to perform an economic analysis and estimate the fee for the practices that carried out by Emergency Nurse Practitioner (ENP) using relative value scale (RVS) and its conversion factor. Methods: First, we developed ENP's RVS for 25 advanced nursing services based on ENP's workload and its time spent by survey. A cost analysis was performed to evaluate the conversion factor of ENP's RVS. The share of ENP's contribution to fee-for-service in emergency setting was also analyzed. Results: Calculation of the RVS of 25 advanced nursing practices showed a range of points from 73.4 to 296.3 and an average of 145.1 points. The relevant conversion factor for advanced nursing practices among ENP was estimated at 12.2~15.9 won. The contribution rate of ENP's advanced nursing practices in the relative value scale of the national health insurance was estimated at 13.1~17.0%. Conclusion: The practices of ENP are not compensated separately and its reimbursement is usually included in physician fee. An estimation of nursing fee and an independent fee related to ENP's services shows the contribution rate to total revenue. It suggests that emergency nurse practitioners be considered as a revenue source the in emergency room.

• Solar Energy
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• v.7 no.1
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• pp.35-41
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• 1987

This paper presents a comprehensive computer simulation of hydrogenated amorphous p-i-n silicon solar cells. The physical mechanism governing solar cell operation has been modeled and solved numerically by Runge-Kutta-Gill method. Effects of gap state density, dopant impurity, diffusion length and interface recombination velocity on solar cell performance are investigated. Numerical results show that the electric field in i-region is not uniform but depends strongly on voltage and position. A rather poor fill factor may be due to the electric field variation and short diffusion length. It is found out that the life time should be improved in order to increase a fill factor and a conversion efficiency.