• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.34-38
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• 2005

Effects of pH level and slurry particle size on material removal rate and planarization of langasite single crystal wafer have been examined. Higher material removal rate was obtained with lower pH level slurries while the planarization was found to be determined by average particle size of colloidal silica slurries. Slurries containing 0.045 ㎛ amorphous silica particles showed the best polishing effect without any scratches on the surface. Effective particle number has a strong effect on the surface planarization and the removal rate, so that the lower effective particle numbers produced low removal rate but the better planarization results.

• Journal of Power Electronics
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• v.17 no.1
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• pp.96-105
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• 2017

In this paper, a hybrid modular multilevel converter (MMC) topology with an improved nearest level modulation method is proposed for medium-voltage high-power applications. The arm of the proposed topology contains N series connected half-bridge submodules (HBSMs), one full-bridge submodule (FBSM) and an inductor. By exploiting the FBSM, half-level voltages are obtained in the arm voltages. Therefore, an output voltage with a 2N+1 level number can be generated. Moreover, the total level number of the inserted submodules (SMs) is a constant. Thus, there is no pulse voltage across the arm inductors, and the SM capacitor voltage is rated. With the proposed voltage balancing method, the capacitor voltage of the HBSM is twice the voltage of the FBSM, and each IGBT of the FBSM has a relatively low switching frequency and an equalized conduction loss. The capacitor voltage balancing methods of the two kinds of SMs are implemented independently. As a result, the switching frequency of the HBSM is not increased compared to the conventional MMC. In addition, according to a theoretical calculation of the total harmonic distortion of the electromotive force (EMF), the voltage quality with the presented method can be significantly enhanced when the SM number is relatively small. Simulation and experimental results obtained with a MMC-based inverter verify the validity of the developed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.719-723
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• 2002

The purpose of this study is to suggest the correlation of single-number ratings for sound insulation by floor impact. As a assessment method of impact sound insulation. we selected the IIC contour of ISO, A weighted sound level. Inverse A-weighting curve and L-Index of japanese industrial standard. And we estimated the single-number ratings by application the measured data of impact sound level to each method. The results showed that the coefficients of determination between each two single-number ratings were very high (more than 0.9169). And In the condition of same assessment method, the coefficient of determination for light-weight impact sound was higher than that for heavy-weight impact sound.

• Korean Journal of Child Studies
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• v.34 no.6
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• pp.159-175
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• 2013

The purpose of this study was to explore how the number of network organizations, network continuity and service continuity of community child centers were affected by the charge factors, organizational factors and environmental factors of community child centers. To better understand this, we researched 107 community child centers in Chonbuk Province. The key results are as follows. The interpersonal connections of the charge factors had a strong effect on the number of network organizations, but organizational factors and environmental factors appeared to have no effect on the number of network organizations. The operational type(religious group), organizational support level of the organizational factors and public-private cooperation, regular consultative group operation(no) of the environmental factors appeared to have an effect on the level of network continuity. The region(local), regular consultative group operation(yes) and public-private cooperation of the environmental factors appeared to have an effect on the level of service continuity. It was hoped that the results would enable us to explore how factors related to a network had an effect on the service continuity, the number of network organizations and clients referral network continuity, and they appeared to have an effect on the service continuity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.3
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• pp.193-200
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• 1992

This study was carried out to determine the optimum fertilizer level of phosphate for maximum yield of soiling cowpea(Vigna sinensis Endlicher) in Cheju. The results obtained are summarized as follows:1. Plant length, fresh yield, stem and leaf weight per plant, node number of main stem, primary branch number per plant, pod number per plant and pod weight per plant increased with increasing of phosphate level regardless of growth stage.2. Plant length and node number of main stem did not increase after August 25, 40 days after planting. Leaf weight and fresh yield were greatest on August 25, and then reduced. 3. Stem weight the number of leaves and pods and pod weight per plant increased until September 13, 80 days after planting. 4. Increased level of phosphate delayed leaf weight decrease after August 25. 5. Root length and root weight per plant increased with increasing level of phosphate regardless of growth stage, and they did not increase after Augest 25. 6. Nodule number and nodule weight per plant also increased as phosphate rate increased regardlessof growth stage. Nodule number and nodule weight were greatest on August 5, and then rapidly decreased.

• Journal of the Korean housing association
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• v.25 no.6
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• pp.39-47
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• 2014

The background of this study is to examine the structure of housing price of which characteristics are not equal but hierarchical in the apartment complexes. So, the purpose of this study is to analyze the influences of apartment complex characteristics on the housing price within the same regional boundary by HLM. The data used as dependent variables were the market prices of 938 units from 29 apartment complexes by stratified sampling. The 2nd level independent variables is the Housing complex characteristics which are composed of the housing complex & locational variables and the 1st level independent variables are the unit characteristics. The results are as follows. First, the first model shows that the 2nd level variables explains 68% of the housing prices. Second, the influential variables of the 1st level unit variable are 'dwelling exclusive area', 'floor of dwelling' and 'direction of dwelling'. Third, the influential variables of the housing complex variables in the 2nd level are 'lot area', 'the building-to-land ratio', 'the number of unit', 'the number of parking lots per unit', 'Green space area' and 'open space area per unit'. The last, the influential variables of the housing locational variables in the 2nd level are 'distance to subway and park' and the number of school and park within a radius of 1km.

• Journal of Korean Academy of Nursing Administration
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• v.14 no.4
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• pp.404-412
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• 2008

Purpose: To analyse hospital nurse staffing level of the general nursing unit, ICU, ER and OR in general hospitals. Method: The study sample was 105 acute general hospitals which had reported the bed size and number of nurses by the nursing units. Number of bed per nurse was analysed by the hospital characteristics and the staffing levels of the doctors and the nursing assistant personnels using t-test or ANOVA and Pearson's correlation. Results: Number of bed per nurse was 3.86 in general nursing units and 0.95 in ICU. Tertiary hospitals employed more nurses in general nursing units and ICU than general hospitals. Hospitals located in Seoul and public hospitals employed more ICU nurses. OR nurse staffing level was higher in academic hospitals. Hospital size was positively correlated with nurse staffing level of the general nursing unit, ICU, ER and OR respectively. Total nurse staffing level of the hospital was positively correlated with doctor and nursing assistant personnels staffing levels. Conclusion : Differentiated nursing fee schedule was needed to implement in ER or OR. Regulation policy should be needed for the hospitals which violated hospital nurse staffing level of the law.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.3
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• pp.27-36
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• 2015

This research studies the adequate size standard of Seogwipo cruise terminal CIQ facility that is scheduled to be built around Gangjeong harbor area in Seogwipo-city. In order to respond to the highly increasing number of passenger cruise ships compared to Seogwipo cruise terminal design in 2010, the adequate size standard of Seogwipo cruise terminal CIQ facility was examined for passenger service level grade. Based on size computation elements such as the number of passengers of cruise ships with the largest size of port entry, ship landing rate, passenger processing ratio, and surge factor, the CIQ facility size for each service level grade was reviewed. As a result, the area of 2,971m2 (A grade), 2,409 m2 (B grade), and 2,088 m2 (C grade) were computed. This showed that the area of B grade was about 82% and C grade 70% compared to the area of A grade. The CIQ facility size computed for each service level grade in this research was analyzed that its area needed to be increased by 322% at least and 458% at most, compared to the CIQ facility area of 649m2 of the existing design (2010). In order to respond to the increasing number of cruise passengers, provide high-level passenger service, and improve the international image of Jeju, Seogwipo cruise terminal should secure the size that is equal to or higher than the B grade of service level.

• Journal of the military operations research society of Korea
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• v.24 no.1
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• pp.176-188
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• 1998

In this paper, it is identified that the optimal level of each performance measures (service and inventory level) is not sensitive to an uncertain environment under JIT Kanban system designed by Moeeni. Moreover, it is proposed that the optimal design method considering multiple performance characteristics is the optimal level decision method according to the relative importance differences of each performance when there exist multiple performance characteristics. The result from the simulation analysis shows that the number of Kanban for stage 3 (final process) and stage 2 is increased at the service level. It is found that the expected loss is minimal when the cycle time decreases and the container size increases. However, the stage 1 is not affected by the number and cycle time of Kanban. It is thus important to consider carefully the cycle time and the container size of the Kanban to satisfy the demand in right time. In case of inventory level, the working inventory level decreases when the container size is decreased and the working inventory level also decreases slightly when the cycle time of the Kankban is increased in stage 1 and 2.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.659-662
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• 2005

In this paper, we proposed the novel hybrid multi-level inverter using combination of the output voltage of transformers to reduce the THD(Total Harmonic Distortion) and improve the waveform of output voltage. The proposed multi-level inverter used the output of transformer which is 1times, 2times, 4times of input of the transformers. So we increased the output voltage from the reduce the number of switching component and transformer. Also, we tested the proposed prototype 15-level inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed multi -level PWM inverter.