• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.121-125
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• 2014

This paper presents a successful stand-alone pico-hydro generation system using a high-efficiency interior permanent-magnet (IPM) synchronous generator. A 1-kW 4-pole V-type IPM generator with low voltage regulation is used for laboratory test in stand-alone hydro energy conversion system. It has been found from experimental results that the constant output voltage is supplied stably by the proposed system under wide speed range.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.383-388
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• 2003

The stand alone PV system's stability and cost is influenced by a design method, as its application products are various. In order to systematize the the stand alone PV system's design method based on experience, this research settled the capacity computation method of PV module and battery and developed a simulator. And Its characteristic is confirmed by applying to PV street lamp design.

• The Korean Journal of Ecology
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• 제6권2호
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• pp.145-151
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• 1983

The epiphytic lichen communities were analysed in terms of cluster analysis on forty two stands and eight environmental variables in Mt. Duckyoo. Ordination of stand and species by principal component analysis (PCA) and sum of square algorithm (SSA) gave similar results. Species cluster showed three groups(I, II, III) and stand revealed three groups (A, B, C). Interaction of stand and species cluster was interpreted by analysis of concentration technique. The results indicated a significant cluster structure at the level of different environment variable.

• Journal of Plant Biology
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• 제23권2호
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• pp.45-48
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• 1980

Effects of habitat and substrate quality on decomposition rate of litters of Larix kaempferi and Quercus serrata were estimated in Kwangnung forest. The amount of organic matter under the canopy of Quercus serrata stand was higher than that under the canopy of Larix kaempferi. The loss constant of litters in the Larix kaempferi stand was higher than that in the Quercus serrata stand.

• 한국산림과학회지
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• 제6권1호
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• pp.32-36
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• 1967

The stand table need to replenish the yield table. It is the distibution of trees in D.B.H. class. Therefore this table was made of sample which was collected to prepared the yield table. The stand table for 6-26 cm was prepared to 2cm interval by method of alinement charts.

• Journal of Power Electronics
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• 제17권2호
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• pp.389-397
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• 2017

A control scheme for stand-alone inverters that utilizes an inductor current observer (ICO) is proposed. The proposed method measures disturbance load currents using a current sensor and it estimates the inductor current using the ICO. The filter parameter mismatch effect is analyzed to confirm the ICO's controllability. The ICO and controllers are designed in a continuous-time domain and transferred to a discrete-time domain with a digital delay. Experimental results demonstrate the effectiveness of the ICO using a 5-kVA single-phase stand-alone inverter prototype. The experimental results demonstrate that the observed current matches the actual current and that the proposed method can archive a less than 2.4% total harmonic distortion (THD) sinusoidal output waveform under nonlinear load conditions.

• The Journal of Korean Physical Therapy
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• 제24권6호
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• pp.383-387
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• 2012

Purpose: Rising from a chair is important for activities of daily living. Several factors have influence on sit-to-stand movement. We studied the effect of inclination of seat surface of on the movement of rising from a chair with electromyographic (EMG). Methods: Twelve subjects performed the sit-to-stand movement on anterior-inclined, standard, and posterior inclined chair. We measured onset time of tibialis anterior and rectus femoris with EMG on each inclination chair. Results: The onset time at the anterior-inclined chair is significantly faster than it at the standard chair (p<0.05). And the onset time at the posterior-inclined chair is significantly slower than it at the standard chair (p<0.05). Conclusion: Rising from anterior inclined chair appeared to be more effective than rising from the standard and posterior inclined chair. Therefore, this finding suggests that the selection of set surface inclination must be considered for activities of daily living during rehabilitation.

• 한국전산유체공학회지
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• 제17권4호
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• pp.69-74
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• 2012

Hypersonic flowfields over a sphere is calculated by using a nonequilibrium flow solver. The flow solver features a two-temperature model and finite rate chemical reaction models to describe nonequilibrium thermochemical processes. For the purpose of validation, the calculated shock stand-off distance is compared with the experimental data which is measured in a ballistic range facility. The present nonequilibrium calculation well reproduced the experimental shock stand-off distance in the cases where the experimental flowfields are expected to be nearly equilibrium, as well as in the cases to be nonequilibrium flowfields in the velocity range 4000 to 5500 m/s.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1635-1645
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• 2015

This study proposes high-performance voltage controller design that employs a capacitor current control model for single-phase stand-alone inverters. The single-phase stand-alone inverter is analyzed via modeling, which is then used to design the controller. A design methodology is proposed to maximize the bandwidth of the feedback controller. Subsequently, to compensate for the problems caused by the bandwidth limitations of the controller, an error transfer function that includes the feedback controller is derived, and the stability of the repetitive control scheme is evaluated using the error transfer function. The digital repetitive controller is then implemented. The simulation and experimental results show that the performance of the proposed controller is high in a 1.5 kW single-phase stand-alone inverter prototype.

• 한국멀티미디어학회논문지
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• 제18권10호
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• pp.1231-1240
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• 2015

Nowadays, in islands where electricity should be provided autonomously, stand-alone microgrid technologies using renewable energy such as sunlight generation and wind power generation come into wide use. The microgrid electricity generation using renewable energy is greatly affected by the natural environment of a site. In order to maintain stable electricity supply for fluctuating electricity generation due to natural environment, the energy management via EMS is positively necessary. In existing stand-alone microgrid EMS, system operation logic is not changeable flexibly because compiled or builded codes are released into the EMS of a site, respectively. In this paper, we designed a flexible operating script-based microgrid EMS Framework for various sites and applied it to some island sites. We could confirm its usability.