• 한국산업융합학회 논문집
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• 제26권4_1호
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• pp.517-527
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• 2023

Many techniques have been proposed and investigated for microlens array manufacturing in three-dimensional (3D) structures. We present fabricating a microlens array using selective laser etching and a CO₂ laser. The femtosecond laser was employed to produce multiple micro-cracks that comprise the predesigned 3D structure. Subsequently, the wet etching process with a KOH solution was used to produce the primary microlens array structures. To polish the nonoptical surface to the optical surface, we performed reflow postprocessing using a CO₂ laser. We confirmed that the micro lens array can be manufactured in three primary shapes (cone, pyramid and hemisphere). Compared to our previous study, the processing time required for laser processing was reduced from approximately 1 hour to less than 30 seconds using the proposed processing method. Therefore, micro lens arrays can be manufactured using our processing method and can be applied to mass productionon large surface areas.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2075-2077
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• 2005

• 대한기계학회논문집A
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• 제30권9호
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• pp.1160-1165
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• 2006

In this paper, the 2-dimensional uniaxial force sensors array is introduced to detect the distributed force using fiber Bragg gratings. Uniaxial force transducer was designed to avoid the chirping and micro bending which degrade the performance of the sensor. The Brags wavelength shift of the sensor was estimated using the finite element analysis. Using this uniaxial force sensor, the uniaxial force sensors array $(3{\times}3)$ was fabricated, and the Performance of this sensors array was evaluated. The Presented sensors may has very simple configuration and its wiring is very simple compared with any other force sensors arrays.

• 디지털융복합연구
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• 제13권2호
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• pp.193-204
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• 2015

배열형 DBMS는 배열형 자료의 저장 및 분석이 가능하므로 과학자들로부터 많은 기대를 받고 있다. 본 논문은 배열형 DBMS를 이용하여 위성원격탐사 영상을 처리하는 방법의 기술이다. 하지만 기존의 연구 방법들은 크게 두 가지 문제가 있다. 첫째, 지구곡률 등에 의해 왜곡된 데이터가 그대로 시각화되는 문제를 가진다. 둘째, 기 작성된 질의를 통해 얻어진 시각화 결과를 다른 분석에 활용하기 어렵다. 따라서 본 논문은 이런 문제점을 해소하고 더 나아가 기존의 2차원 시각화가 아닌 위성원격탐사 영상의 3차원 시각화 방법을 제안한다. 아울러 논문의 세부적인 연구내용은 다음과 같다. 첫째, 위성원격탐사 영상을 배열 데이터베이스에 저장, 분석, 가공하는 방법을 기술한다. 둘째, 가공된 결과물의 3차원 시각화 방법을 제안한다. 마지막으로 본 논문의 학술적 기여도는 배열형 DBMS에서의 위성원격탐사 영상의 활용 방법과 함께 위성데이터의 3차원 시각화 기법을 제안했고, 위성원격탐사 영상의 활용범위 확대에 기여할 것으로 요약된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2004년도 춘계학술발표대회 및 제6회 신소재 심포지엄
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• pp.47-47
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• 2004

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.28-29
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• 2004

Optical wireless mobile communications have the potential to provide wide bandwidth and security . We have proposed and designed the 2-dimensional tracking optical receiver systems for optical wireless mobile communication. The receiver system consist of 4${\times}$4 photodiode array can receive optical signal from the transmitter. The room size is 5${\times}$5m$^2$ and the room height is 3m.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2015년도 추계학술대회
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• pp.43-44
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• 2015

LTE-Advanced system has been deployed with 2 and 4 transmission antennas (Tx) while the specification supports up to 8Tx. Due to deployment space, antenna dimension and complexity, the needs of deploying 8Tx system has not been motivated by operators. Recently, three dimensional (3D) beamforming with active antenna has attracted significant attention in the wireless industry. By incorporating 2D active array into LTE-A systems, the system offers freedom in controlling radiation on elevation and horizontal dimension. When the number of antennas increases in the form of 2D arrangement, spatial separation can be realized simultaneously in horizontal and elevation domain and vertical beam-steering can increase SINR of UEs in high floors. In this paper, we study the system operations and implementations for supporting 3D beamforming with 8Tx antennas. In our schemes, by reusing the conventional CSI feedback framework, the system can operate 2D active array without harming the backward compatibility. Evaluation results show that 3D beamforming provides capacity boosting over the conventional 2D beamforming systems while keeping same antenna structure.

• 전자공학회논문지A
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• 제31A권4호
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• pp.127-135
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• 1994

In this paper we propose an EWLD(Enhanced Weighted Levenshtein Distance) algorithm to organize code-string pattern matching linear array processor based on the mappting to an one-dimensional array from a two-dimensional matching matrix, and design a processing element(PE) of the processor, N PEs are required instead of NS02T in the processor because of the mapping. Data input and output between PEs and all internal operations of each PE are performed in bit-serial fashion. The bit-serial operation consists of the computing of word distance (WD) by comparison and the selection of optimal code transformation path, and takes 22 clocks as a cycle. The layout of a PE is designed based on the double metal $1.5\mu$m CMOS rule. About 1,800 transistors consistute a processing element and 2 PEs are integrated on a 3mm$\times$3mm sized chip.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.282-285
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• 2010

We printed a one-dimensional array of metallic wires and a two-dimensional array of metallic split ring resonators on a photo-paper by using a high-dots-per-inch resolution printer and an ink with silver nano-particles. The printed sample sizes are $1.0{\times}1.0cm^2$. The transmission measured by a terahertz time domain spectroscopy system shows that the arrays of wires and split ring resonators could act as polarizers and band-stop filters, respectively, in a terahertz frequency region.

• 한국정보전자통신기술학회논문지
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• 제3권2호
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• pp.31-38
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• 2010

PBG 구조의 메타물질 설계시 패턴 형태와 배열 구조에 따른 금지대역(bandgap)을 정확하게 설계하기 어려운 문제가 있다. 본 논문에서는 2차원 배열구조로 어떤 모양의 패턴에 대해서도 빠르고 정확하게 원하는 금지대역을 설계할 수 있는 방법을 제안한다. 2차원 평면상의 메타물질 구조는 주기배열로 이루어져 있기 때문에 FDTD 수치해석 방법에 주기경계조건을 부여함으로서 계산영역을 줄였다. 또한 각 패턴이 갖는 L, C 값을 2차원적으로 고려하여 계산하였기 때문에 보다 정확한 설계가 가능하였다. 5GHz 대역에서 정사각형 패턴을 갖는 메타물질을 설계하여 기존의 마이크로스트립 선로를 이용한 1차원 메타물질 해석 값과 비교하였을 때 정확도가 평균적으로 14.7% 향상됨을 확인할 수 있었다.