• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.48-48
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• 2009

최근 나노광전소자 응용에 큰 관심을 받는 물질인 산화물 나노선은 앞으로 불어 올 나노소재 시대를 여는 선두 물질이다. 이러한 산화물 나노선 가운데 가장 큰 관심을 받는 물질로는 산화아연 나노선을 들 수 있다. 삼화아연 나노선은 상온에서 큰 엑시톤 결합에너지 및 큰 밴드갭을 가지고 있으며 투명성 및 소자구동시 안정성을 지니고 있어 그 응용이 기대된다. 하지만 이러한 나노선을 이용한 광전소자 응용은 bottom-up 방식을 기초로 한 대면적 소자제작이 어렵다. 이러한 bottom-up 방식의 나노소자 제작에서 필요한 나노선 성장기술은 금속 catalyst 없이 대면적 성장, 나노선 수직어레이, 나노선의 고온성장, 기판 사이에 발생하는 자발적 계면층 제거 등으로 대표된다. 또한 나노선의 결정성 및 광특성 향상을 위해서는 고온성장이 불가피한데, 실리콘 기판과 같이 격자상수 불일치도가 큰 기판에서는 나노선 성장이 이루어지지 않고 다시 탈착되어 구조물이 성장되지 않는다. 본 연구에서는 선택적 삼원계 단결정 씨앗층을 이용하여 길이/직경 비가 매우 향상된 MgZnO 나노와이어를 interfacial layer 없이 수직으로 고온에서 성장하여 산화물 전계방출 에미터로서의 가능성을 확인하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.49-55
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• 2013

A high-voltage highly-integrated analog front-end (AFE) IC for medical ultrasound imaging applications is implemented using standard 0.18-${\mu}m$ CMOS process. The proposed AFE IC is composed of a high-voltage (HV) pulser utilizing stacked transistors generating up to 15 Vp-p pulses at 2.6 MHz, a low-voltage low-noise transimpedance preamplifier, and a HV switch for isolation between the transmit and receive parts. The designed IC consumes less than $0.15mm^2$ of core area, making it feasible to be applied for multi-array medical ultrasound imaging systems, including portable handheld applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1046-1055
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• 1994

In this paper, to design high speed 1 line VRAM(Video RAM) suitable for image signal processing with ASIC(Application Specific IC) method, the VRAM memory core has been designed using 3-TR dual-port dynamic cell which has excellent access time and integration characteristics. High speed pipeline operation was attained by separating the first row from the subarray 1 memory core and the simultaneous I/Q operation for a selected single address was made possible by adopting data-latch scheme. Peripheral circuits were designed implementing address selector and 1/2V voltage generator. Integrated ASIC has been optimized using 1.5[ m] CMOS design rule.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.95-100
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• 2016

We suggest and simulate an optical filter that a red wavelength range cannot transmit to protect the psychological stress that originates from the cognition of red color in emergency medical technicians. When a nanohole hexagonal array is fabricated on gold film using Anodic Aluminum Oxide (AAO), the blocked wavelength can be tuned by the hole diameter and film thickness. The characteristic of the transmittance for normal incident white light is simulated with Finite Element Method (FEM) in the MATLAB platform. Although the transmittance of the overall wavelength is reduced by 50% by the gold film, the transmittance of the red wavelength range is decreased by over 87%.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.5
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• pp.77-86
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• 1995

In this paper in order to reduce the encoding complexity required in the full search vector quantization(VQ), a new classified vector quantization(CVQ) technique is described employing the minimum-distance classifier. The determination of the optimal subcodebook sizes for each class is an important task in CVQ designs and is not an easy work. Therefore letting the subcodebook sizes be equal. A CVQ technique. Which satisties the optimal CVQ condition approximately, is proposed. The proposed CVQ is a kind of the partial search VQ because it requires a search process within each subcodebook only, and the minimum encoding complexity since the subcodebook sizes are the same in each class. But simulation results reveal while the encoding complexity is only O(N$^{1/2}$) comparing with O(N) of the full-search VQ. A simple systolic array, which has the through-put of k, is also proposed for the implementation of the VQ. Since the operation of the classifier is identical with that of the VQ, the proposed array is applied to both the classifier and the VQ in the proposed CVQ, which shows the usefulness of the proposed CVQ.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.93-102
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• 2000

This paper describes the architecture and characteristics of the satellite modem unit (SMU) developed for the DAMA-SCPC Ground System(DGS), which is a Demand Assignment Multiple Access-Single Channel per Carrier (DAMA-SCPC) satellite network. There are several requirements for the SMU from the system architecture and design concept. To meet these requirements the SMU was designed and implemented by extensively applying digital signal processing (DSP) technique and field programmable gate array (FPGA). The developed SMU met the functional and performance requirements, and has been working well. The measured BER was about 1 $\times$10E-4 in continuous mode(at Eb/No=4.7, FEC=3/4).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1575-1582
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• 1998

Reed-Solomon(RS) code which is especially effective against burst error is studied as a forward error correction technique in this ppaer. The circuits of RS encoder and decoder for ASIC implementation are designed and presented employing modified Euclid's algorithm. The functionalities of the designed circuits are verified though C programs which simulates the circuits over the various errors and erasures. The pipelined circuits using systolic arrays are designed for ASIC realization in VHDL, and verified through the logic simulations. Finally the circuit synthesis of RS encoder and decoder can be achieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.399-406
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• 2011

Adaptive beamformers, which utilize a priori information on the arrival angle of the desired signal. suppress interferences while maximizing their gains in the desired signal direction. However, if there exist errors in the direction information, they can suffer from severe performance degradation since the desired signal is treated as an interference. A robust adaptive beamforming method is presented which exploits the signal-blocking structure of the Duvall beamformer. The proposed method finds an interference signal space directly from correlations of received signals and then obtains a weight vector such that it is orthogonal to the space. Applying the weight vector to two sub arrays which consist of one less sensors than the original uniform lineal array (ULA), the beamformer efficiently estimates the arrival angle of the desired signal. Its computational complexity is lower than existing methods, which require matrix inversion or eigendecomposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.415-416
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• 2008

The finite element model was used to simulate the temperature distribution of a arrayed vertical-cavity surface-emitting laser (VCSEL). In this work, the dimension of AlGaAs/GaAs based VCSEL array was $50{\mu}m$ active diameter and $250{\mu}m$ pitch, and AuSn solder of 80wt%Au-20wt%Sn was included to flip-chip bond. The results of the thermal simulation will be applied to predict the thermal cross-talk in high speed parallel optical interconnects.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.195-198
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• 2002

현재의 광통신, 이동통신 및 디지털 시대에서는 보다 소형화되고, 대용량의 데이터 저장 및 다기능 소자에 대한 요구가 많아지고 있다. 이러한 전자 산업 환경에서 MEMS 소자는 여러 요구조건을 만족시킬 수 있는 특징을 갖추고 있으며 실제 소자의 제작에 있어서 MEMS 소자를 이용하여 여러 물리 및 화학 센서 및 Actuator 제작에 응용이 되어지고 있고 Optical switch, Gyroscope, 적외선 어레이 센서, 가속도 센서, 위치 센서 등 여러 분야에서 실용화가 진행되어지고 있다. MEMS 구조물의 packaging 방법에 있어서는 내부 MEMS 소자의 동작을 위한 외부 환경으로부터의 보호를 위하여 Hermetic sealing에 대한 요구를 만족시켜야 한다. 본 발표에서는 이와 같은 MEMS device의 진공 패키지를 구현함에 있어서 기판 내부에 수동소자를 실장할 수 있는 LTCC 기술을 이용하여 진공 패키징하는 방법에 대하여 소개한다. 본 기술을 이용하는 경우 기존의 Hermetic sealing 이외에 향후 적층 기판 내부에 수동소자를 내장시켜 배선 길이 및 노이즈 성분을 감소시켜 더욱 전기적 성능을 향상시킬 수 있는 장점이 있게된다. 본 논문에서는 LTCC 기판을 이용하여 패키징 시킨 후, 내부 진공도에 영향을 줄 수 있는 계면들에서의 시간에 따른 진공도 변화의 특성치를 측정하여 LTCC 기판의 Hermetic sealing 특성에 관하여 조사하였다.