• Progress in Superconductivity
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• v.3 no.1
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• pp.36-40
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• 2001

We have studied vortex dynamics in$ Bi_2$$Sr_2$$CaCu_2$O$_{8}$single crystals of unirradiated and irradiated samples by using 100 $\times$ $100\mu\textrm{m}^2$Hall sensor. Doses equivalent magnetic fields are 20 G, 100 G and 1 kG. In the magnetization measurement, a second magnetization peak (SMP) was observed in unirradiated, 20 G dose and 100 G dose samples in contrast to 1 kG dose sample. In the unirradiated sample, the SMP was observed in the range of 18 K ~ 35 K and the amplitude of the SMP decreased with increasing temperature. With increase of the irradiation dose, temperature region and sharpness of the SMP were reduced. In the magnetic relaxation measurement, we observed that the normalized relaxation rate S decreased with increasing the irradiation dose. Our results suggest that the vortex dynamics is not greatly affected by low-density columnar defects.s.

• Annual Conference of KIPS
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• 2022.05a
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• pp.397-400
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• 2022

본 연구에서는 소셜 네트워크 서비스(Social Network Service, SNS) 데이터로부터 약물 부작용 게시글을 추출하기 위한 순환 신경망(Recurrent Neural Network, RNN) 기반 분류 모델을 제안한다. 먼저, 처방 빈도가 높으며 게시글을 많이 확보할 수 있는 케토프로펜 약물에 대하여 국내 최대 소셜 네트워크 플랫폼인 네이버 블로그와 카페의 게시글(2005 년~2020 년)을 확보하고 최종 3,828 건을 분석하였다. 결과적으로 케토프로펜에 대한 3 종(약물, 부작용, 불용어)의 렉시콘을 정의하였으며 이를 기반으로 Bi-LSTM 분류모델 기준 87%의 정확도를 얻었다. 본 연구에서 제안하는 모델은 SNS 데이터가 약물 부작용 정보 획득을 위한 기존 (전자의무기록, 자발적 약물 부작용 보고 시스템 등) 자료원에 대한 보완적 정보원이 되며, 개발된 Bi-LSTM 분류모델을 통해 약물 부작용 게시글 추출의 편리성을 제공할 것으로 기대된다.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.49.1-49
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.289-290
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• 2007

• Bulletin of the Korean Chemical Society
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• v.24 no.7
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• pp.885-886
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• 2003

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.872-879
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• 2010

This paper describes the design for radiation pattern directivity of vehicle license plate RFID tag antenna to improve the readable range. Directivity pattern of the proposed passive antenna is decided by the meander line position and the bumper size attached to the tag antenna. In order to prove the verification of the calculated directivity pattern and readable range of the proposed antenna, the tag antenna has been fabricated and measured at the anechoic chamber. It is shown that the maximum directivity gain of the measured radiation pattern of active and passive tag antenna were observed 2.32 dBi and 3.1 dBi, respectively. The maximum readable range of passive tag antenna was measured about 8.5 m at ${\pm}45^{\circ}$ beam direction on the basis of the driving car direction($0^{\circ}$ of azimuth angle).

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.89-100
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• 2008

In an urban network controlled by traffic signals, there is an interaction between the signal timing and the routes chosen by individual road users. This study develops a bi level programming model for traffic signal optimization in networks with path based traffic assignment. In the bi level programming model, genetic algorithm approach has been proposed to solve upper level problem for a signalized road network. Path based traffic assignment using column generation technique which is proposed by M.H. Xu, is applied at the lower-level. Genetic Algorithm provieds a feasible set of signal timings within specified lower and upper bounds signal timing variables and feeds into lower level problem. The performance of this model is investigated in numerical experiment in a sample network. In result, optimal signal settings and user equilibrium flows are made.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.275-279
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• 2013

Objective : This study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI). Methods : Twenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0). Results : Redlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores. Conclusion : On the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.

• Journal of the Korean Vacuum Society
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• v.14 no.3
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• pp.153-158
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• 2005

The effective mean free path model was adopted to examine the thickness effect on the thermoelectric properties of flash-evaporated n-type $Bi_2Te_{2.4}Se_{0.6}$ thin films. Annealing effects on the electron concentration and mobility were also studied, and their variations were analyzed in conjunction with antisite defects. Seebeck coefficient and electrical resistivity versus inverse thickness showed a linear relationship, and the mean free path was found to be $5120\AA$ Electron mobility was increased by annealing treatment and electron concentration was decreased considerably due to reduction of antisite defects, so that electrical conductivity was decreased and Seebeck coefficient was increased. When annealed at 473k for 1 hour, Seebeck coefficient and electrical conductivity were $-200\;\mu V/k\;and\;510\omega^{-1}cm^{-1}$, respectively. Therefore, the thermoelectric power factor was improved to be $20\times10^{-4}\;W/(mK^2)$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.298-303
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• 2003

Bi$_4$-$_{x}$EU$_{x}$Ti$_3$O$_{12}$ (BET) thin films were etched by inductively coupled CF$_4$/Ar plasma. We obtained the maximum etch rate of 78 nm/min at the gas mixing ratio of CF$_4$(10%)/Ar(90%). The variation of volume density for F and Ar atoms are measured by the optical emission spectroscopy. As CF$_4$increased in CF$_4$/Ar plasma, the emission intensities of F increase, but Ar atoms decrease, which confirms our suggestion that emission intensity is proportional to the volume density of atoms. From X-ray photoelectron spectroscopy, the intensities of the Bi-O, the Eu-O and the Ti-O peaks are changed. By pure Ar plasma, intensity peak of the oxygen-metal (O-M : TiO$_2$, Bi$_2$O$_3$, Eu$_2$O$_3$) bond was seemed to disappear while the intensity of pure oxygen peak showed an opposite tendency. After the BET thin films was etched by CF$_4$/Ar plasma, the peak intensity of O-M bond increase slowly, but more quickly than that of peak belonged to pure oxygen atoms due to the decrease of Ar ion bombardment. Scanning electron microscopy was used to investigate etching Profile. The Profile of etched BET thin film was over 85$^{\circ}$./TEX>.