• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.226-229
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• 2008

Hot press forming is an advanced forming technology fur manufacturing of complex and crash-resistant automotive parts using ultra high strength steels. The 3-dimensional FE analysis of hot press forming process, in which process the deformation, heat transfer and phase transformation behavior are fully coupled, is carried out. The vast amount of material properties for the FE analysis is obtained from material properties calculation software which is based on thermodynamic calculations. The overall methodology for the FE analysis of HPF process and the analysis results are discussed here.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.2
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• pp.115-121
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• 2002

This paper presents an evolutionary design of digital IIR filters using the genetic algorithm (GA) with modified genetic operators and real-valued encoding. Conventional digital IIR filter design methods involve algebraic transformations of the transfer function of an analog low-pass filter (LPF) that satisfies prescribed filter specifications. Other types of frequency-selective digital fillers as high-pass (HPF), band-pass (BPF), and band-stop (BSF) filters are obtained by appropriate transformations of a prototype low-pass filter. In the GA-based digital IIR filter design scheme, filter coefficients are represented as a set of real-valued genes in a chromosome. Each chromosome represents the structure and weights of an individual filter. GA directly finds the coefficients of the desired filter transfer function through genetic search fur given filter specifications of minimum filter order. Crossover and mutation operators are selected to ensure the stability of resulting IIR filters. Other types of filters can be found independently from the filter specifications, not from algebraic transformations.

• Journal of Sensor Science and Technology
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• v.29 no.2
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• pp.75-81
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• 2020

We introduce a new visible light communication (VLC) method in which three-level return-to-zero (RZ) modulation is used for flicker-free transmission. In the VLC transmitter, the three-level RZ modulation ensures that the average optical power is constant; thus, a flicker-free light-emitting diode (LED) light is achieved. In the VLC receiver, a resistor-capacitor high-pass filter is used for generating spike signals, which are used for data recovery while eliminating the 120 Hz optical noise from adjacent lighting lamps. In transmission experiments, we applied this method for wireless transmission of an air quality sensor message using the visible light of an LED array. This configuration is useful for the construction of indoor wireless sensor networks for air pollution monitoring using LED lights.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.107-109
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• 2003

Optical sensor-based land cover categories produce spectral signature confusion along with degraded classification accuracy. In the classification tasks, the goal of fusing data from different sensors is to reduce the classification error rate obtained by single source classification. This paper describes the result of land cover/land use classification derived from solely of Landsat TM (TM) and multisensor image fusion between JERS 1 SAR (JERS) and TM data. The best radar data manipulation is fused with TM through various techniques. Classification results are relatively good. The highest Kappa Coefficient is derived from classification using principal component analysis-high pass filtering (PCA+HPF) technique with the Overall Accuracy significantly high.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.522-527
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• 2000

본 논문은 그레이이미지를 컬러이미지로 변환하는 의사칼라이미지 향상에 관한 연구이다. 적용기법은 그레이이미지의 시간영역신호를 주파수영역으로 변환하고 LPF, BPF, HPF 2차원필터를 통과시켜 시간영역으로 역 변환한 후 각각에 대해 히스토그램 평활화하여 RGB 신호를 구하는 과정에서 의사 칼라를 얻는다. 실험 결과 필터주파수가 증가함에 따라 PSNR도 증가하고 낮게 설정하면 경계부분의 화질이 좋아진다. 2차원 주파수필터의 사용은 칼라 변환 시 강조하고자 하는 부분을 보다 자유롭게 변환할 수 있고 다양한 컬러 이미지로 향상되어 영상분석에 효과가 있다. 의사칼라의 변환에 의한 식별 인식능력은 9dB 정도 향상된다.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.3-5
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• 2004

Balanced input 단을 갖는 IC chip과의 interface를 위하여 2.4GHz 대역의 Balun BPF를 설계하였다. $2.4{\times}2.0 (mm)$ 크기의 LTCC chip 형태로 제작하기위하여 LPF-HPF 형태를 응용한 집중소자형 Balun을 설계하고 Comb-line 형태의 BPF를 접합하여 설계 및 시뮬레이션을 하였다. 시뮬레이션 결과 Balun BPF의 삽입손실은 3.03dB, 위상차는 $170^{\circ}$, Amplitude balance는 0.09dB이다.

• Journal of Chest Surgery
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• v.34 no.1
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• pp.97-100
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• 2001

흉막의 고립성 섬유성 종양은 중피하에 존재하는 미분화 중배엽성 기원의 섬유 세포에서 기원하는 종양으로 알려졌다. 이 종양은 대부분 양성으로 보고되고 있으나 병리학적으로 높은 세포 밀도, 유사분열의 수가 많고(10개의 고배율 시야에서 4개 이상), 핵의 다양성, 출혈, 괴사등이 있으며 악성의 판단기준으로 보고된다. 환자는 62세 여자로 호흡곤란 및 기침을 주소로 본원에 입원하였으며 단순 흉부 방사선 및 전산화 단층 촬영상 우측 흉강내에 거대한 종양소견이 보였다. 이 종양은 23$\times$18$\times$12 cm, 2 kg의 크기와 무게를 가졌으며 우측폐 하엽과 중엽은 압박되어있었으나 종양 절개 후 재 팽창됨을 확인하였다. 또한 횡경막과 심하게 유착되어 박리도중 손상이 동반되어 봉합술이 필요하였다. 병리학적으로 종괴는 세포밀도가 높았고 방추형세포의 다발로 이루어져 있었으며 유사분열의 수가 많이(27 mitosis/10HPF)보였다. 면역 조직 화학 검사상 vimentin과 CD34에 양성 반응을 보였다. 이에 악성 고립성 섬유성 종양으로 확진되었다. 본 교실에서는 흉막에 발생한 악성 고립성 섬유성 종양을 치험하였기에 문헌 고찰과 함께 보고한다.

• Transactions of Materials Processing
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• v.25 no.4
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• pp.242-247
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• 2016

CFD simulation with FlowVision^® is used to evaluate the capability of cooling channel in hot press forming dies. Two different types of cooling channels, dry drilled and pocket types are considered for comparison. Two different approaches for simulating cooling channel are considered. One is single-phase velocity calculation for coolant only and the other is multiphase thermal and velocity calculation for die, blank and coolant all together. Both approaches show better cooling performance in pocket type cooling channel. Also both approaches show their own effectiveness in designing cooling channel of hot press forming dies.

• Animal cells and systems
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• v.13 no.4
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• pp.411-418
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• 2009

We are reporting the identification, expression patterns, and possible biological functions of zebrafish kif3b (kif3bz) encoding 475 amino acids. Kif3Bz contains the kinesin motor domain, catalytic domain, KISc domain, and one single coiled coil domain. Phylogenetic analysis indicates that kif3bz is a highly conserved gene among the tested vertebrates. First of all, both maternal and zygotic messages of kif3bz were evenly distributed in the blastomeres at 2-cell stage. Its ubiquitous expression throughout the blastomeres continued till 40% epiboly. However, kif3bz transcripts became restricted in Kupffer's vesicle at tailbud and 6-somite stages. At 13-somite stage, kif3bz expression pattern became specific to the telencephalon, diencephalon, trigeminal placode, and somites. Such expression patterns were further intensified in the telencephalon, diencephalons, hind brain, pronephric ducts, optic vesicles, and spinal cord neurons in the 23-somite stage embryos, and last till 24 hpf. We discussed possible functions of Kif3Bz related to the vertebrate embryonic development.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.584-586
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• 2005

The stroke of piston in the linear compressor driven by LPMSM can be obtained from integrating the input voltage and current of LPMSM, and may be diverged due to dc components In the voltage and current. The strategy to prevent the divergence of stroke using both the high-pass filter and dc offset compensation was suggested. The equations for the magnitude and phase of the stroke and also dc offset including the stroke are derived as a function of the cut-off frequency of HPF. The performance of stroke calculation scheme has been verified by experimentally on a linear compressor drive system, where the control was implemented by a 16-bit DSP.