• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4849-4854
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• 2015

It has been often occurred for the outside components(BU, SVaC, DB) of UM71c AF track circuits to be broken down caused by some pieces of falling ice in the winter time or by infrastructure repairing equipments while facility maintenance works since 2004, opening of Kyeongbu High Speed Rail Express. In this paper, we proposed that we could move the outside components of UM71c track circuit out of wayside from present place. Then we can assure that the life time of those components would be extended. So we simulated the electrical characteristics by changing cable length using MATLAB Simulinks and we designed the compensation capacitor. Also, we obtained the same results as those of simulation by field demonstration test on site. The design specifications obtained from this field verification test could be applied in the absent section of track circuit, if only have a little more intensified research to compensate changed electrical characteristics and to redesign inner impedance of the track circuit.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1130-1131
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• 2006

본 논문은 고속선에 사용 중인 UM71-C 궤도회로에 대한 전기적인 특성에 관한 시뮬레이션 실행결과를 나타낸다. 고속선 운행선상의 샘플개소를 선정하여 환경에 따른 선로정수를 구하고 전송라인의 특성임피던스와 전파정수를 반영시켜 레일전압과 전류에 대한 시뮬레이션을 수행하였으며, 차상검측시스템에서 측정되어진 검측데이터 파형과 비교하였다. 이러한 모델링 작업은 궤도회로 구성요소의 기능저하를 사전 예측하여 열차의 안전운행을 확보하기 위한 기초자료로 사용되어 질 수 있으며, 또한 차상검측시스템에서 얻어진 검측데이터와의 비교를 통해 유지보수에 활용 가능한 활용지침 및 분석기준을 작성하기 위해 필요하다.

• 한국해양학회지
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• v.26 no.1
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• pp.77-82
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• 1991

Phytoplankton chlorophyll-a concentrations and primary productivities were measured and analyzed in the adjacent waters of Kori Nuclear Power Plant where thermal effluent is being discharged chlorophyll-a concentrations were ranged from 1.89 to 12.8 ug/l. Nanoplankton 9cell size; 3∼20 um) fractions of the total chlorophyll-a concentrations were ranged from 4.60 to 65.95% and picoplankton (cell size<3um) fractions contributed from 15.71 to 83.20%. Primary productivities measured by C 14 method were ranged from 165.17 to 645.79 mgC/m$^2$ /day and, nanoplankton and picoplankton contribution rate to the total primary productivity were ranged from 8.06 to 43.98% and from 19.64 to 81.45% respectively. these results imply that very tiny cell sized phytoplankton population are important in point of biomass and primary productivity of phytoplankton communities.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.779-785
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• 2006

This paper introduces a result of internal signal modeling for a defect diagnosis of the UM-71C track circuit using on HSL. Actually, We fixed a sample area within operating section on HSL and performed the simulations for short circuit current that is reflected characteristic impedance and propagation factor. We compared the measuring data with the result of the simulation. These modeling can be used as the basic data for secure of the safety. Also, It need to make a criteria of analysis for the maintenance through comparison simulation data and inspection data.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.27-35
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• 2008

This work proposes a 14b 150MS/s 0.13um CMOS ADC for SDR systems requiring simultaneously high resolution, low power, and small size at high speed. The proposed ADC employs a calibration-free four-step pipeline architecture optimizing the scaling factor for the input trans-conductance of amplifiers and the sampling capacitance in each stage to minimize thermal noise effects and power consumption at the target resolution and sampling rate. A signal- insensitive 3-D fully symmetric layout achieves a 14b level resolution by reducing a capacitor mismatch of three MDACs. The proposed supply- and temperature- insensitive current and voltage references with on-chip RC filters minimizing the effect of switching noise are implemented with off-chip C filters. The prototype ADC in a 0.13um 1P8M CMOS technology demonstrates a measured DNL and INL within 0.81LSB and 2.83LSB, at 14b, respectively. The ADC shows a maximum SNDR of 64dB and 61dB and a maximum SFDR of 71dB and 70dB at 120MS/s and 150MS/s, respectively. The ADC with an active die area of $2.0mm^2$ consumes 140mW at 150MS/s and 1.2V.

• 대한생식의학회:학술대회논문집
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• 1999.11a
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• pp.71.2-72
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• 1999

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.69-75
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• 2004

This work proposes an 8b 220 MS/s 230 mW 3-stage pipeline CMOS ADC with on-chip filers for temperature- and power- insensitive voltage references. The proposed RC low-pass filters improve switching noise performance and reduce reference settling time at heavy R & C loads without conventional off-chip large bypass capacitors. The prototype ABC fabricated in a 0.25 um CMOS occupies the active die area of 2.25 $\textrm{mm}^2$ and shows the measured DNL and INL of maximum 0.43 LSB and 0.82 LSB, respectively. The ADC maintains the SNDR of 43 dB and 41 dB up to the 110 MHz input at 200 MS/s and 220 MS/s, respectively, while the SNDR at the 500 MHz input is degraded as much as only 3 dB than the SNDR at the 110 MHz input.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1656-1664
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• 2007

This paper introduces a study of improvement for a defect diagnosis of the UM71C track circuit using on HSL. The track circuit on HSL has long operation section. Therefore, when the worker maintain, many times and efforts are spent. So, periodically, we have operated a inspection car. However, we don't know exactly the state changed of the inspection data when track circuit has defect. Actually, We fixed a sample area within operation section on HSL and performed the simulations for short circuit current that is reflected characteristic impedance and propagation factor. We compared the measuring data with the result of the simulation. Using verified simulation program, we estimated inspection data as the malfunction number and the change of capacity of compensation capacitor. These study need to secure of the safety as the train operation. Also, It needs to make a criteria of analysis for the maintenance through comparison simulation data and inspection data.

• Natural Product Sciences
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• v.19 no.1
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• pp.71-75
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• 2013

Actinofuranone C (1), a new 3-furanone-bearing polyketide, was isolated from an actinobacterium (Amycolatopsis sp.) associated with a female of the dung beetle, Copris tripartitus Waterhouse. The structure of actinofuranone C was elucidated by the spectroscopic interpretation of NMR, mass, UV, and IR data. The discovery of actinofuranone C indicates that chemical investigation of insect-associated microorganisms would be an effective strategy to explore natural chemical diversity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.71-75
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• 2005

For the damage tolerance improvement of conventional laminated composites, stitching process have been utilized for providing through-thickness reinforcements. 2D preforms were stacked with S-2 glass plain weave and S-2 glass MWK (Multi-axial Warp Knit) L type. 3D preforms were fabricated using the stitching process. All composite samples were fabricated by RTM (Resin Transfer Molding) process. To examine the damage resistance performance the low speed drop weight impact test has been carried out. For the assessment of damage after the impact loading, specimens were examined by scanning image. CAI (Compressive After Impact) tests were also conducted to evaluate residual compressive strength. Compared with 2D composites, the damage area of 3D composites was reduced by 20-30% and the CAI strength showed 5-10% improvement.