• Journal of Electrical Engineering and Technology
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• v.6 no.3
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• pp.408-413
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• 2011

In this paper, a real-coefficient approach to Adaptive Frequency Sampling (AFS) technique is developed for efficient equivalent circuit modeling of RF components. This proposed method is advantageous than the vector fitting technique and the conventional AFS method in terms of fewer samples leading to a lower order of a rational function on a given data and to a direct conversion to an equivalent circuit for PSPICE(Personal Simulation Program with Integrated Circuit Emphsis) simulation, respectively. To validate the proposed method, the distributed equivalent circuit of a presented multi-layered RF low-pass filter is obtained using the proposed real-coefficient AFS, and then comparisons with EM simulation and circuit simulation for the device under consideration are achieved.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.304-311
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• 2001

The present work examines the influence of surface coating on the temperature and the thermo-mechanical stress field produced by friction due to sliding contact. A two-dimensional transient model of a layered medium submitted to a moving heat flux is prsented. A solution technique based on the boundary element method employing the multiregion technique is utilized. Results are presented showing the influence of coating thickness, thermal properties, Peclet number, and mechanical properties. It has been shown that the mechanical properties and thickness of coating have a significant influence on the stress field, even for low temperature increase. The effects of the ratios of shear modulus become more important for low temperature increase than the effects of the ratios of other mechanical properties.

• Computational Structural Engineering
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• v.9 no.2
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• pp.173-182
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• 1996

The present study proposes a detection technique for delaminations in a laminated compoiste structure. the proposed technique optimizes the spatial distribution of harmonic excitation so as to magnify the difference in response between the delaminated and intact structures. The technique is evaluated by numerical simulation of two-layered aluminum beams. Effects of measurement and geometric noises are included in the analysis. A finite element model for a delaminated beam, based on the layer-wise laminated plate theory in conjunction with a step function to simulate ddelaminations, is used.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.5-21
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• 1998

The purpose of this paper is to show that X-ray absorption spectroscopy (XANES and EXAFS) is a powerful technique for characterizing both crystalline and amorphous solids from structural (local order) and electronic point of view. The principle of this technique is briefly described by showing the main factors which must be considered for recording and fitting the experimental results. Some non-trivial examples have been selected for demonstrating that XAS spectroscopy is the only technique for bringing a definitive answer as for example: the determination of the local distortion of the $NiO_6$ octahedra in the $Li_{1-z}Ni_{1+z}O_2$ layered oxides and the evidence of the presence of copper pairs in the NASICON-type phosphate $CuZr_2 (PO_4)_3$. Are also reported some significant examples for which XAS spectroscopy is decisive with other characterization methods as (i) Raman spectroscopy for glasses (ii) Mossbauer spectroscopy for $LiNi_{1+z-t}Fe_To_2$ oxides (iii) magnetic measurements for Ce-based intermetallic compounds.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.6-14
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• 2007

In this paper, we propose and observe the Adaptive Modulation system with optimal Turbo Coded V-BLAST (Vertical-Bell-lab Layered Space-Time) technique that is applied the extrinsic information from MAP (Maximum A Posteriori) Decoder in decoding Algorithm of V-BLAST: ordering and slicing. The extrinsic information is used by a priori probability and the system decoding process is composed of the Main Iteration and the Sub Iteration. And comparing the proposed system with the Adaptive Modulation system using conventional Turbo Coded V-BLAST technique that is simply combined V-BLAST with Turbo Coding scheme, we observe how much throughput performance has been improved. In addition, we observe the proposed system using STD (Selection Transmit Diversity) scheme. As a result of simulation, Comparing with the conventional Turbo Coded V-BLAST technique with the Adaptive Modulation systems, the optimal Turbo Coded V-BLAST technique with the Adaptive Modulation systems has better throughput gain that is about 350 Kbps in 11 dB SNR range. Especially, comparing with the conventional Turbo Coded V-BLAST technique using 2 transmit and 2 receive antennas, the proposed system with STD (Selection Transmit Diversity) scheme show that the improvement of maximum throughput is about 1.77 Mbps in the same SNR range.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.61-70
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• 2007

In this paper, we propose and observe the Adaptive Modulation system with optimal Turbo Coded V-BLAST(Vertical-Bell-lab Layered Space-Time) technique that is applied the extrinsic information from MAP Decoder in decoding Algorithm of V-BLAST: ordering and slicing. And comparing the proposed system with the Adaptive Modulation system using conventional Turbo Coded V-BLAST technique that is simply combined V-BLAST with Turbo Coding scheme, we observe how much throughput performance and SNR has been improved. In addition, we show that the proposed system using STD(Selection Transmit Diversity) scheme results in on improved result, By using simulation and comparing to conventional Turbo Coded V-BLAST technique with the Adaptive Modulation systems, the optimal Turbo Coded V-BLAST technique with the Adaptive Modulation systems has SNR gain over all SNR range and better throughput gain that is about 350Kbps in 11dB SNR range. Also, comparing with the conventional Turbo Coded V-BLAST technique using 2 transmit and 2 receive antennas, the proposed system with STD scheme show that the improvement of maximum throughput is about 1.77Mbps in the same SNR range and the SNR gain is about 5.88dB to satisfy 4Mbps throughput performance.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.467-470
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• 1999

An analytical method based on the nonlinear layered finite element method is developed to simulate overall load-deflection behavior of bonded and unbonded prestressed concrete beams. The model which uses rather advanced numerical technique for iterative convergence to equilibrium can be regarded as superior one compared to the models mainly based on either load control or displacement control methods. Model predictions were compared with preceding experimental results and it was observed that there were good agreements between them.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.1135-1139
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• 1989

Three layered neural network was applied for the pattern recognition problem of human spermatozoa in clinical test. The goodness of recognition rate was studied in relation to the number of hidden layer cells and of output layer cells. The proposed method provided better results than conventional template matching technique. Parallel processing of the back propagation learning algorithm was also studied using transputers and its performance was evaluated.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.745-747
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• 2001

대역폭이 보장되지 않는 인터넷 상에서 대용량의 멀티미디어 데이터를 실시간으로 서비스하는 것은 여러가지 문제점을 안고 있다. 이에 미디어 데이터의 전송량을 줄이기 위한 연구로서 layered coding을 통한 스케일러블 전송에 대한 연구가 시도되었다. 본 논문에서는 MPEG 비디오 스트림의 스케일러블 전송을 가능케 하기 위하여 Temporal-Fidelity Scaling 기법을 제안하며, MPEG-4 Visual Component에서의 적용 방법에 대해 제안하고자 한다.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.319-326
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• 2002

During the construction period of submarine shield tunnel, which is built firstly in very soft marine clay layer 40m deep in Korea, wide range problems were encountered such as safe launching against high earth pressure at shield entrance, technique of shield face pressure control when passing through complex multi-layered soils This paper introduces successful construction practice through development of state-of-the-art construction method and field monitoring.