• Smart Structures and Systems
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• 제10권4_5호
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• pp.313-329
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• 2012

A challenging issue in design and implementation of an effective structural health monitoring (SHM) system is to determine where a number of sensors are properly installed. In this paper, research on the optimal sensor placement (OSP) is carried out on the Canton Tower (formerly named Guangzhou New Television Tower) of 610 m high. To avoid the intensive computationally-demanding problem caused by tens of thousands of degrees of freedom (DOFs) involved in the dynamic analysis, the three dimension finite element (FE) model of the Canton Tower is first simplified to a system with less DOFs. Considering that the sensors can be physically arranged only in the translational DOFs of the structure, but not in the rotational DOFs, a new method of taking the horizontal DOF as the master DOF and rotational DOF as the slave DOF, and reducing the slave DOF by model reduction is proposed. The reduced model is obtained by IIRS method and compared with the models reduced by Guyan, Kuhar, and IRS methods. Finally, the OSP of the Canton Tower is obtained by a kind of dual-structure coding based generalized genetic algorithm (GGA).

• Geomechanics and Engineering
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• 제16권1호
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• pp.85-95
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• 2018

Water affects the mechanical properties of coal and stress wave propagation. To comprehensively investigate the effect of water content on the properties of coal, laboratory tests including X-Ray Diffraction (XRD) analysis, P-wave test, S-wave test, static and dynamic compression test with different water contents were conducted. The compressive strength, elastic modulus and failure strain and their mechanism of coal specimen under coupled static-dynamic load with the increased water content were observed. Meanwhile, energy transmission and dissipation characteristics of a stress wave in coal specimens with different water contents under dynamic load and its relation with the failure features, such as fragmentation and fractal dimension, of coal was analyzed. Furthermore, the dynamic interpretation of water infusion to prevent coal burst based on water infusion model of coal seam roadway was provided.

• Journal of Power Electronics
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• 제14권6호
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• pp.1166-1177
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• 2014

A new type of topology with medium-frequency-transformer (MFT) isolation for medium voltage wind power generation systems is proposed in this paper. This type of converter is a high density power conversion system, with high performance features suitable for next generation wind power systems in either on-shore or off-shore applications. The proposed topology employs single-phase cascaded multi-level AC-AC converters on the grid side and three phase matrix converters on the generator side, which are interfaced by medium frequency transformers. This avoids DC-Link electrolytic capacitors and/or resonant L-C components in the power flow path thereby improving the power density and system reliability. Several configurations are given to fit different applications. The modulation and control strategy has been detailed. As two important part of the whole system, a novel single phase AC-AC converter topology with its reliable six-step switching technique and a novel symmetrical 11-segment modulation strategy for two stage matrix converter (TSMC) is proposed at the special situation of medium frequency chopping. The validity of the proposed concept has been verified by simulation results and experiment waveforms from a scaled down laboratory prototype.

• 한국전기전자재료학회논문지
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• 제18권10호
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• pp.941-944
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• 2005

In this experiment, OLEDs(Organic Light Emitting Diodes) was fabricated to confirm effect of Plasma treatment which increase the hole injection characteristic from anode. Device structure was $ITO/2-TNATA/{\alpha}-NPD/DPVBi/BAlq/Alq_3/Al:Li$. We used DPVBi (4, 4 - Bis (2,2-diphenylethen-1-yls) - Biphenyl) as a blue emitting material. To optimize the process condition of plasma treatment, we used 2 gases of the oxygen and nitrogen gas under 120 mTorr with 100 W, 200 W, and 400 W plasma power. The current efficiency of $N_2$ plasma is more efficient than that of $O_2$ plasma. At $1000 cd/m^2$, we obtained the maximum current efficiency of 6.45 cd/A using $N_2$ gas with 200 W plasma power.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.62-65
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• 2010

ITS는(지능형 교통 시스템: Intelligent Transport System)을 이용한 대중교통을 더욱 편리하게 이용하기 위하여 본 논문은 버스와 지하철의 도착 정보를 공용으로 서버처리 시스템을 연동하여 관리하고 네트워크로 실시간 정보를 사용자에게 전송하여 그로 인해 사용자가 편리하게 사용하며, 대중 교통 이용의 효율성을 위해서 관련된 기술이 최근 동향을 분석 간다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.124-127
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• 2000

The purpose of this study is to research and develop PAn-Carbon composite electrode for Supercapacitor. Supercapacitor cell of PAn-Carbon composite electrode with 1M $LiClO_{4}/IPC$ brings out good capacitor performance below 4.0V. The radius of semicircle of PAn-Carbon composite electrode adding 30wt% Acetylene Black was absolutely small. The total resistance of Supercapacitor cell mainly depended on internal resistance of he electrode. The discharge capacitance of PAn-Carbon on composite with 30wt% Acetylene Black in 1st and 50th cycles was 29 and 31F/g at current density of $1mA/cm^2$. The capacitance of PAn-Carbon composite with 30wt% Acetylene Black capacitor was larger than that of PAn capacitor without Acetylene Black. The coulombic efficiency of supercapacitor at discharge process of 1 and 50 cycles were 94 and 100%. respectively. PAn-Carbon composite Supercapacitor with 30wt.% Acetylene Black content showed good capacitance and stability with cycling.

• 천문학회보
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• 제42권2호
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• pp.52.3-53
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• 2017

Identification of gravitational wave (GW) sources in electromagnetic (EM) wave observations is important because it enables us to understand the property of the GW-emitting sources/mechanisms much better than the GW detection. For that reason, a large number of astronomers are working on observations to identify the position and the nature of GW sources. We give a short overview of the expected EM signals from GW sources and the current EM follow-up observations that have been undertaken in Korea and the world.

• 동의생리병리학회지
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• 제34권2호
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• pp.97-101
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• 2020

Oral leukoplakia is the most common premalignant lesion of the oral mucosa. This case report presents the effect of acupuncture on Oral leukoplakia. The 67 years old male patient who has suffered for 2 years was treated with Right side Saam acupucture Damjeonggyeok(BL66, GB43, LI1, GB44) without other treatment. Acupuncture was performed for 15 minutes. The effect of acupuncture was evaluated as photographic change and visual analog scale(VAS) of subjective symptoms in oral cavity. After 87th acupunture treatment during 226 days, Leukoplakias were decreased at the right side of ventral tongue and the left border of the tongue and the lower lip. Furthermore, ulcer, erosion at the left border of the tongue were disappeared and VAS of Burning pain in the tongue decreased from 8 to 2. Although acupuncture is unusual treatment for Oral Leukoplakia, this case report suggested the effectiveness of using Damjeonggyeok on Oral Leukoplakia according to Saam acupuncture method.

• Structural Monitoring and Maintenance
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• 제3권2호
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• pp.115-127
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• 2016

It is a challenging problem of assessing the location and extent of structural damages with vibration measurements. In this paper, an improved Extended Kalman filter (EKF) with Tikhonov regularization is proposed to identify structural damages. The state vector of EKF consists of the initial values of modal coordinates and damage parameters of structural elements, therefore the recursive formulas of EKF are simplified and modal truncation technique can be used to reduce the dimension of the state vector. Then Tikhonov regularization is introduced into EKF to restrain the effect of the measurement noise for improving the solution of ill-posed inverse problems. Numerical simulations of a seven-story shear-beam structure and a simply-supported beam show that the proposed method has good robustness and can identify the single or multiple damages accurately with the unknown initial structural state.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.4153-4156
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• 2012

Purpose: To investigate the efficacy and toxicity of a combination of gemcitabine with nedaplatin (GN) or cisplatin (GC) for patients with unresectable or recurrent esophagus squamous cell carcinoma. Methods: Gemcitabine was administered at 1 g/m2 intravenously on days 1 and 8; and nedaplatin or cisplatin were administered at 80 mg/m2 intravenously on day 1. We analyzed the response rate, overall survival time, progression-free survival time, and toxicity in 21 patients treated with GN and 27 patients treated with GC. Results: In patients treated with gemcitabine plus nedaplatin, the ORR was 47.6%, the median progression-free survival time was 4.1 months, and the median survival time was 9.3 months. In patients treated with gemcitabine plus cisplatin, the ORR was 48.2%, the median progression-free survival time was 3.9 months, and the median survival time was 9.1 months, respectively. There were no statistically significant differences in ORR, PFS and OS between the two groups. In both, the most commonly observed toxicities were thrombocytopenia and fatigue. Nausea and vomiting was more frequent in the GC group than in the GN group. Conclusion: Gemcitabine based chemotherapy was effective and tolerable for patients with unresectable or recurrent esophagus squamous cell carcinoma refractory to first line chemotherapy.