• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.205-215
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• 2001

Continuously variable transmission(CVT) mechanisms considered here combine the functions of a 2K-H I type differential gear unit and a V-belt continuously variable unit(CVU). One shaft of the V-belt CVU is connected directly to the differential gear unit and remaining shaft of it is linked to the output shaft. These mechanisms have many advantage which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. In this paper six different mechanisms of output coupled type CVT are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed, and theoretical analysis are proven by various experiments.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.199-208
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• 2003

Continuously variable transmission (CVT) mechanisms considered here combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit (CVU). As combining the functions of a K-H-V type differential gear unit and a V-belt type CVU, 24 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. These mechanisms have many advantages which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.386-387
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• 2013

This paper provides a comparison of high power semiconductor devices in 5MW-class Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) wind turbines. High power semiconductor devices of IGBT module type, IGBT press-pack type, and IGCT of both 4.5kV and 6.5kV are considered in this paper. Benchmarking is performed based on neutral-point clamed 3-level back-to-back type voltage source converter supplied from grid voltage of 4160V. The feasible number of semiconductor devices in parallel is designed through the loss analysis considering both conduction and switching losses under the given operating conditions of 5MW-class PMSG wind turbines, particularly for the application in offshore wind farms. The loss analysis is confirmed through PLECS simulations. The comparison result shows that IGBT press-pack type semiconductor device has the highest efficiency and IGCT has the lowest cost factor considering the necessary auxiliary components.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.5
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• pp.389-399
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• 2016

This study was performed to investigate the hepatotoxicity reducing effect of ethanol extracts from Youngia denticulata Houtt Kitamura (YD) fermented by Aspergillus oryzae, which is well known as a Korean traditional meju microbe. Experimental rats were divided into 4 diets groups (six rats/group) (NC: normal control group, EC: ethanol supplemented control group, ENY: ethanol extracts 0.5% supplemented diets of the non-fermented YD group, EFY: ethanol extracts 0.5% supplemented diets of the fermented YD group). After feeding them for four weeks, the activities GOT and GPT in serum, contents of neutral lipid, total cholesterol, LPO and GSH, and activities of XO (O type) enzyme, SOD and GST in liver tissue were observed. Compared to the NC group, the GOT and GPT activities in the EC group were markedly increased by 87.91% and 57.02%, and the contents of neutral lipid, total cholesterol and LPO were increased by 77.51%, 18.56% and 193.86%, respectively. On the other hand, the GSH content was decreased by 29.52%. The activities of SOD and GST which are anti-oxidation-related enzymes, were decreased by 42.78% and 0.94%, respectively, compared to the NC group, but the XO (O type) enzyme activity was significantly increased by 70.83%. These results confirmed that the liver tissue and anti-oxidation system of the EC group had been damaged. Compared to the EC group, the GOT and GPT activities of the ENY and EFY groups were significantly decreased by 24.73~41.99% and 22.91~30.11%, respectively. The contents of neutral lipid, total cholesterol and LPO were decreased by 16.65~33.33%, 22.44~23.11% and 63.34~66.13%, respectively, but the GSH content was significantly increased by 24.61~35.60%. The GST activity was not significantly affected, but the SOD activity was significantly increased by 214.94~261.19%. The XO (O type) enzyme activity was significantly decreased by 40.34~51.20%. Compared to the ENY group, the GOT and GPT activities of the EFY group were significantly decreased by 22.93% and 9.34%, respectively. The plasma contents of neutral lipid, total cholesterol and LPO were decreased by 20.01%, 0.86% and 7.59%, respectively. The SOD activity was significantly increased by 21.52%, and the XO (O type) enzyme activity was decreased by 18.19%. Given decreasde TG, total cholesterol, LPO contents of liver tissue, GOT, GPT and XO activity, and increased SOD activity, these study results that ethanol extracts from fermented Youngia denticulata Houtt Kitamura may be effective in reducing hepatotoxicity.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.72-80
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• 2004

Electrolytic dissolution study was carried out to evaluate the applicability of electrochemical decontamination process using a neutral salt electrolyte as a decontamination technology for the recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant using SUS-304 and Inconel-600 specimen as the main materials of internal system components of the plant. The effects of type of neutral salt as an electrolyte, current density, and concentration of electrolyte on the dissolution of the materials were evaluated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as $UO_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion plant were peformed in $Na_2SO_4$ and $NaNO_3$ solution. It was verified that the electrochemical decontamination of the dismantled metallic wastes was quite successful in $Na_2SO_4$ and $NaNO_3$ neutral salt electrolyte by reducing $\beta$ radioactivities below the level of self disposal with authorization within 10 minutes regardless of the type of contaminants and the degree of contamination.

• Language and Information
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• v.10 no.1
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• pp.1-20
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• 2006

We can distinguish two different groups of 'fusion expressions' depending on whether the verb (-ko) ha- 'do' can be recovered from the contracted expression concerned or not: recoverable and unrecoverable fusion expressions. Many expressions belonging to the former group show alternations between the [da]-type and the [dae]-type: e.g., o-nta-nta and o-ntae-nta '...says... is coming.' On the other hand, some expressions like ka-ntae can only be realized as the [dae]-type. The main purpose of this paper is to account for these [dae]-type expressions. First, we assume that they have an inaudible/invisible quotation $verb\;{\phi}-$, which takes as its complement a verb phrase with a neutral speech-level ending. This quotation verb is derived from the quotation verb ha-. Second, we assume that the quotation $verbs\;{\phi}-$ and ha- have the [j] sound as their stem-final element, which means that these verbs are actually represented as ${\phi}-j-$ and ha-j-, respectively. In this system, the [tae]-type expressions come out naturally from the behavior of the [j] sound. We do not employ any ad hoc phonological rules to derive the [dae]-type expressions from the corresponding [da]-type expressions.

• Applied Microscopy
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• v.27 no.2
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• pp.155-163
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• 1997

Ultrastructural and histochemical studies were carried out on the prostate gland of a Korean slug (Incilaria fruhstorferi) with light and electron microscopes. The results are as follows. The endothelial tissue of the prostate gland is constituted with tall and narrow ciliated columnar cells, irregularly shaped cells and gland cells in which are included the elongated oval or ellipsoid nucleus those are surrounded by curved membrane. The endothelial tissue of the prostate gland is composed by type-A, B, C and type-D gland cells, and the glanules of type-A, B, and D gland cells are certified to neutral mucopolysaccharide because are related by PAS-alcian blue (pH 2.5) , but the other hand type-C gland cell is only weakly reacted to PAS, but strongly reacted by Million reaction. The glanules of type-A gland cell are small size (about $0.4{\mu}m$) and are seen high electron density, but the glanules of type-B gland cell are large size (about $0.7{\mu}m$) and glanule density is same type-A glanules. Long ellipsoid type-C gland cell contained round nucleus which is well developed beterochromatin in, and that small oval glanules (size, about $0.9{\mu}m$) of moderate high electron density which are formed a group of large glanule together with $4\sim5ea$, but type-D gland cell possessed round small nucleus are seen high electron dense glanules (size, $0.8{\mu}m$).

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.213-224
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• 2023

Type II solar radio bursts show frequency drifts from high to low over time. They have been known as a signature of coronal shock associated with Coronal Mass Ejections (CMEs) and/or flares, which cause an abrupt change in the space environment near the Earth (space weather). Therefore, early detection of type II bursts is important for forecasting of space weather. In this study, we develop a deep-learning (DL) model for the automatic detection of type II bursts. For this purpose, we adopted a 1-D Convolution Neutral Network (CNN) as it is well-suited for processing spatiotemporal information within the applied data set. We utilized a total of 286 radio burst spectrum images obtained by Hiraiso Radio Spectrograph (HiRAS) from 1991 and 2012, along with 231 spectrum images without the bursts from 2009 to 2015, to recognizes type II bursts. The burst types were labeled manually according to their spectra features in an answer table. Subsequently, we applied the 1-D CNN technique to the spectrum images using two filter windows with different size along time axis. To develop the DL model, we randomly selected 412 spectrum images (80%) for training and validation. The train history shows that both train and validation losses drop rapidly, while train and validation accuracies increased within approximately 100 epoches. For evaluation of the model's performance, we used 105 test images (20%) and employed a contingence table. It is found that false alarm ratio (FAR) and critical success index (CSI) were 0.14 and 0.83, respectively. Furthermore, we confirmed above result by adopting five-fold cross-validation method, in which we re-sampled five groups randomly. The estimated mean FAR and CSI of the five groups were 0.05 and 0.87, respectively. For experimental purposes, we applied our proposed model to 85 HiRAS type II radio bursts listed in the NGDC catalogue from 2009 to 2016 and 184 quiet (no bursts) spectrum images before and after the type II bursts. As a result, our model successfully detected 79 events (93%) of type II events. This results demonstrates, for the first time, that the 1-D CNN algorithm is useful for detecting type II bursts.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.131-138
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• 2013

In this paper, I propose and evaluate the method that classifies emotional type of characters with their emotional words. Emotional types are classified as three types such as positive, negative and neutral. They are selected by classification of emotional words that characters speak. I propose the method to extract emotional words based on WordNet, and to represent as emotional vector. WordNet is thesaurus of network structure connected by hypernym, hyponym, synonym, antonym, and so on. Emotion word is extracted by calculating its emotional distance to each emotional category. The number of emotional category is 30. Therefore, emotional vector has 30 levels. When all emotional vectors of some character are accumulated, her/his emotion of a movie can be represented as a emotional vector. Also, thirty emotional categories can be classified as three elements of positive, negative, and neutral. As a result, emotion of some character can be represented by values of three elements. The proposed method was evaluated for 12 characters of four movies. Result of evaluation showed the accuracy of 75%.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1458-1469
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• 2018

This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT2Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the $3LT^2Is$ can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.