• Electronics and Telecommunications Trends
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• v.34 no.3
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• pp.65-74
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• 2019

The Earth Stations in Motion (ESIM) system is one of the most modern satellite systems, providing high-speed and high-capacity communication with mobility. To facilitate ESIM in the Ka band, operational, technical, and regulatory studies have been conducted in the International Telecommunication Union Radiocommunication Sector (ITU-R) since 2016. In this paper, we introduce the ESIM and discuss its system characteristics and frequency sharing issues with respect to existing services in the same frequency bands. Taking into account current standardization activity in the ITU-R, we provide the latest study results of ESIM operation based on the Conference Preparatory Meeting Report for the World Radiocommunication Conference-19.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.428-434
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• 2017

In recent years, owing to the growing user demand for the two-way internet service based on the mobile global broadband communications, a new type of satellite terminal has been developed, known as ESIM(Earth Station in Motion). This service was required by Resolution 158(WRC-15) to study on the coexistence with the co-primary FS(Fixed Service) in 27.5-29.5 GHz as a FSS(Fixed Satellite Service) uplink. In this paper, the average received power on ESIM within -10 dB of beam width of FS and its outage probability was analyzed theoretically and also simulated to account for the azimuth angle with uniform distribution. From the results, it can be concluded that this theoretical analysis is very useful to analyze the interference from ESIM into FS based on the statistical and probabilistic method. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the inclination angle of moving path, the operation hours, and the speed of ESIM to protect the co-primary FS.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.503-510
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• 2016

In recent years, owing to the growing user demand for the two-way internet service based on the move global broadband communications, a new type of satellite terminal has developed, known as earth station in motion (ESIM). This service was required by Resolution 158 (WRC-15) to study on the coexistence with the co-primary fixed service (FS) in 27.5-29.5 GHz as a FSS uplink. In this paper, four scenarios was introduced to account for the antenna pointing error and the azimuth for an analysis on the sharing between ESIM and FS. From analysis results, the required separation distance between two systems should be about 32~52 km according to the elevation angles of $20^{\circ}{\sim}40^{\circ}$ using thresholds of 5% and 10% outage probability. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the pointing error of ESIM to minimize the required separation distance and to protect the co-primary FS.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.393-396
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• 1996

This paper studies electrostatically suspended induction motors (ESIM). The ESIM possesses the rotating ability of an ordinary electrostatic induction motor, in addition to providing contactless support by electrostatic suspension. To accomplish these two functions, a feedback control strategy and the operating principle of an ordinary electrostatic induction motor are used. The stator possesses electrodes which exert the electrostatic forces to the rotor and are divided into a part responsible for suspension and one for rotation. Two rotor types are utilized: a polished glass disk without any surface treatment, and a polished glass disk covered with a thin layer of conductive material (ITO layer) on only one side. In this paper, the principle of the ESIM is described, followed by stator electrode design, experimental apparatus, control strategy for stable suspension. Experimental results show that the glass disk has been rotated with a speed of approximately 70 rpm while being suspended stably at a gap length of 0.3 mm.

• Annual Conference on Human and Language Technology
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• 2018.10a
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• pp.40-43
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• 2018

대화 발화 예측(Next Utterance Classification)은 Multi-turn 대화에서 마지막에 올 발화를 정답 후보들 중에서 예측을 하는 연구이다. 기존에 제안된 LSTM 기반의 Dual Encoder를 이용한 모델에서는 대화와 정답 발화에 대한 관계를 고려하지 않는 문제와 대화의 길이가 너무 길어 중간 정보의 손실되는 문제가 존재한다. 본 연구에서는 이러한 두 문제를 해결하기 위하여 ESIM구조를 통한 단어 단위의 attention, 대화의 turn별 문장 단위의 attention을 제안한다. 실험 결과 총 5000개의 검증 대화 데이터에 대하여 1 in 100 Recall@1의 성능이 37.64%로 기존 모델 대비 약 2배 높은 성능 향상을 나타내었다.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.434-439
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• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.262-266
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• 1999

Thirty plants were screened for their antioxidative activity. The extracts of Agastache rugosa, Schizonepeta tenuifolia and Lycopus lucidus had high free radical(2,2-diphenyl-1-picrylhydrazyl) scavenging activities. Methanol extract of Agastache rugosa was fractionated with hexane, chloroform, ethyl acetate, and water. The ethyl acetate fraction showed the highest antioxidant activity in the DPPH test. The ethyl acetate fraction was applied to Sephadex LH-20 column, and the fractions showing antioxidative activity were collected and used for identification of the substance. The purified substance was applied to mass, IR, UV and NMR spectroscopy. The spectra of mass, IR, UV and NMR implied that the substance is a rosmarinic acids as a kind of phenolic compound. The rosmarinic acid has more antioxidative effect than those of BHT and ${\alpha}-tocopherol$ in the Rancimat test.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.135-144
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• 2013

The aim of this study was to evaluate various aspects of Vitex negundo L. leaf extract, such as the antioxidative activity, tyrosinase inhibitory effects, and inhibitory activities on ${\alpha}$-MSH induced melanogenesis, and active component analysis. The DPPH (1, 1-diphenyl-2-picrylhydrazyl) scavenging activities ($FSC_{50}$) of the ethyl acetate fraction and aglycone fraction of V. negundo L. leaf extract were $14.51{\mu}g/ml$ and $13.96{\mu}g/ml$, respectively. A luminol-dependent chemiluminescence assay revealed that the reactive oxygen species (ROS) scavenging activity ($OSC_{50}$) of the aglycone fraction of V. negundo L. leaf extract on ROS generated in an $Fe^{3+}$-$EDTA/H_2O_2$ system was the most prominent at $0.22{\mu}g/ml$. The protective effects of the extracts fractions of V. negundo L. leaf against the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner ($1{\sim}50{\mu}g/ml$). In particular, there were greater protective effects of the aglycone fraction on the cellular membrane than that of the fat-soluble antioxidant (+)-${\alpha}$-tocopherol. The inhibitory effects ($IC_{50}$) on mushroom tyrosinase were the highest for the ethyl acetate fraction ($IC_{50}$ = $48.58{\mu}g/ml$). The inhibitory effect on ${\alpha}$-MSH induced melanogenesis in B16 melanoma cells was 41.80% at $50{\mu}g/ml$ of ethyl acetate fraction. Active component analyses by TLC, HPLC and LC/ESI-MS revealed luteolin and isoorientin. These results indicate that V. negundo L. leaf extract can be used as an antioxidant for ROS scavenging. Particularly, the luteolin and isoorientin of the ethyl acetate fraction may be applicable to new whitening cosmetics because of its inhibitory effect on mushroom tyrosinase and ${\alpha}$-MSH induced melanogenesis in B16 melanoma cells.