• 한국항행학회논문지
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• 제27권5호
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• pp.610-620
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• 2023

4차 산업 혁명에 기반한 기술발전 및 항공사들의 고객 유치를 위한 경쟁으로 인해 항공기 인테리어 시장에 대한 관심이 증가하고 있으며, 그 일환으로 국내에서는 FAA Part.25급 민항기를 대상으로 한 CDS (Cabin Display System)이 개발되고 있다. CDS는 IDPM (Integrated Display Processing Module)로 제어되는 대형 Flexible 및 투명 OLED (Organic Light Emitting Diodes)를 활용하여 승객들에게 다양한 멀티미디어 서비스를 제공하는 시스템으로 고품질의 서비스 제공을 위해 대용량의 미디어 콘텐츠 활용이 필수적으로 요구된다. 본 논문에서는 대용량 파일들의 효율적인 Data Load Process를 수행하기 위한 새로운 방안을 제시하고 그 구현 및 성능을 다룬다. 본 연구 결과는 기존 ARINC-615A 대비 Data Load Process 개발 비용의 절감과 더불어 신뢰성 높은 대용량 파일 전송이 필요한 항공 장비의 Data Load Process 개발에 대체 적용이 가능할 것으로 기대된다.

• Progress in Superconductivity
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• 제11권1호
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• pp.42-46
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• 2009

With an aim of comparison, single grain Y-Ba-Cu-O (YBCO) bulk superconductors were fabricated using a liquid infiltration growth (LIG) process and a conventional melt growth (MTG) process with top seeding. The MTG process uses an $YBa_2Cu_3O_{7-x}$(Y123) powder as a precursor, while the LIG process uses $Y_2BaCuO_5(Y211)/Ba_3Cu_5O_8(Y035)$ pre-forms. The growth of a single Y123 domain on the top seed was successful in the both processes. Different feature between the two processes is the interior microstructure regarding the critical current density ($J_c$). The LIG-processed YBCO sample showed a lower porosity, more uniform distribution of Y211 particles and the enhanced Y211 refinement compared to the conventional MTG process. The $J_c$ improvement in the LIG process is attributed to the dispersion of finer Y211 particles as well as lower porosity within the Y123 superconducting matrix.

• 한국군사과학기술학회지
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• 제22권3호
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• pp.332-340
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• 2019

Electronic warfare systems are needed to be advantageous in the modern war. Many radar threat signals with various frequency spectrums and complicated techniques exist. For detecting the threats, a receiver with wide and narrow-band digital processing is needed. To process a wide-band searching mode, a polyphase filter bank has become the architecture of choice to efficiently detect threats. A polyphase N-path filter aligns the re-sampled time series in each path, and a discrete Fourier transform aligns phase and separates the sub-channel baseband aliases. Multiple threats and CW are detected or rejected when the signals are received in different sub-channels. And also, to process a narrow-band precision mode, a direct down converter is needed to reduce aliasing by using a decimation filter. These digital logics are designed in a FPGA. This paper shows how to design and develop a wide and narrow-band digital receiver that is capable to detect the threats.

• 한국전기전자재료학회논문지
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• 제36권3호
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• pp.203-213
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• 2023

Owing to carbon materials' diverse functionalization and versatility, the design and synthesis of carbon-based three-dimensional porous structures have become important foundational research topics across various fields. Among the various methods for producing porous carbon structures, laser-induced graphene (LIG) has garnered attention because of its large surface area, controllable structure, excellent electrical conductivity, scalability, and eco-friendly synthesis process. In addition, recent research results have reported more novel functionalities by advancing further from the unique characteristics of LIG through functionalization or compounding of LIG, making it an attractive material for various applications in electronic devices, sensing, catalysis, and energy storage. This review aims to update the research trends in LIG and its functionalization, providing insights to inspire more interesting studies on functional LIG to expand its potential applications ultimately. Starting with the synthesis method and material characteristics of LIG, we introduce the functionalization of LIG, which is classified into surface modification, heteroatom doping, and hybridization based on the interaction mechanism. Finally, we summarize and discuss the prospects of LIG and its functionalization.

• 전기학회논문지
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• 제67권3호
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• pp.406-412
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• 2018

This paper describes the fabrication process of laser induced graphene (LIG) and its transfer method on to a flexible and stretchable PDMS substrate. By irradiating CO2 laser on a polyimide(PI) film surface, a localized high temperature is created, resulting in a three-dimensional porous graphene network structure with good conductivity. This LIG electrode is relatively easy to fabricate and since it is very weak the LIG electrode was transferred to a flexible PDMS substrate to increase the sturdiness as well as possible use in flexible applications. Sheet resistance, thickness, and electrochemical activity of the fabricated in-situ LIG electrodes have been examined and compared with the LIG electrodes after transferring to PDMS elastomer. The properties of the LIG electrodes were also examined depending on the $CO_2$ laser power. As the irradiated laser power increased, the LIG electrode resistance decreases and the LIG electrode thickness increased. At 4.8 W of laser power, the average sheet resistance and thickness of the fabricated LIG electrodes were approximately $31.7{\Omega}/{\Box}$ and $62.67{\mu}m$, respectively. Moreover, the electrochemical activity of the fabricated LIG electrode at 4.8 W of laser power showed a high oxidation current of $28.2{\mu}A$ after transferring to PDMS.

• 한국추진공학회지
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• 제19권6호
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• pp.91-97
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• 2015

HTPB/AP/Al 계열의 혼합형 열경화 추진제를 적용한 로켓 연구개발에 있어서의 추진제 기계물성 규격을 정하는 일련의 과정을 고찰하고, 공정지수를 통하여 추진제 제조에서의 공정관리를 분석하였다. 이를 근간으로 기계물성간의 종속성을 분석하고 최적화 물성을 제시함으로서 불량률을 제거하는 공정 안전도 향상뿐만 아니라 추진제 그레인의 구조적 안전도 상승에도 기여할 것이다.

• 한국멀티미디어학회논문지
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• 제22권9호
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• pp.1000-1010
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• 2019

Image semantic segmentation and dehazing are key tasks in the computer vision. In recent years, researches in both tasks have achieved substantial improvements in performance with the development of Convolutional Neural Network (CNN). However, most of the previous works for semantic segmentation assume the images are captured in clear weather and show degraded performance under hazy images with low contrast and faded color. Meanwhile, dehazing aims to recover clear image given observed hazy image, which is an ill-posed problem and can be alleviated with additional information about the image. In this work, we propose a deep multi-task network for simultaneous semantic segmentation and dehazing. The proposed network takes single haze image as input and predicts dense semantic segmentation map and clear image. The visual information getting refined during the dehazing process can help the recognition task of semantic segmentation. On the other hand, semantic features obtained during the semantic segmentation process can provide cues for color priors for objects, which can help dehazing process. Experimental results demonstrate the effectiveness of the proposed multi-task approach, showing improved performance compared to the separate networks.

• 시스템엔지니어링학술지
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• 제17권1호
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• pp.1-10
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• 2021

In this paper we proposed the alternative analysis of reliability design using redundancy technique. First, we presented the process for establishing the reliability design alternative analysis process considering the active redundancy and the standby redundancy. and then, the case analysis of A driving equipment was performed in accordance with the reliability design alternative analysis process presented. In case the series reliability design result is not met with the reliability target value. so, the target item for redundancy design of A driving equipment were selected as items with a severity of two or higher. The redundancy design applied with active and standby redundancy techniques were analyzed using BlockSim software. As a result, it was analyzed that reliability design to active redundancy with one of two elements required for A driving equipment is the most efficient compared to the target value of reliability. The results of this study can be usefully used before the reliability design is performed.

• 한국항행학회논문지
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• 제22권2호
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• pp.84-89
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• 2018

국내 기술의 발달로 인하여 다양한 항공기 발사 무장이 개발되고 있으며, 항공기-무장통합 인증에 대한 중요성 역시 높아지고 있다. 항공기-무장 통합 인증은 표준감항인증기준 (Standard ACC; standard airworthiness certification criteria)에서 제시하는 무장/장착물 통합 기준에 대한 적합성을 검증하여 안전 비행에 문제가 없다는 것을 증명하는 것으로, 무장 개발 후 항공기 통합 과정에서 요구되는 다양한 기준을 만족시켜야 함을 의미한다. 따라서 항공기의 요구사항을 무장 개발 과정에서 반영하여야 적합성 검증 단계에서 설계 변경 소요를 줄일 수 있다. 본 논문에서는 표준감항인증기준과 항공기-무장적합성 기준문서인 MIL-HDBK-1763, 그리고 순항유도무기 개발 프로세스간의 상관성을 분석하였다. 분석 결과 설계 초기 단계부터 공력 및 구조설계 분야에서 항공기 요구사항을 반영하여 개발을 진행하는 경우 항공기-무장 통합 인증 단계에서의 설계 변경 발생을 줄일 수 있다고 판단하였다.

• International Journal of Internet, Broadcasting and Communication
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• 제12권2호
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• pp.30-36
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• 2020

We demonstrated a successful fabrication of 4" Gallium Nitride (GaN)/Diamond High Electron Mobility Transistors (HEMTs) incorporated with Inner Slot Via Hole process. We made in manufacturing technology of 4" GaN/Diamond HEMT wafers in a compound semiconductor foundry since reported [1]. Wafer thickness uniformity and wafer flatness of starting GaN/Diamond wafers have improved greatly, which contributed to improved processing yield. By optimizing Laser drilling techniques, we successfully demonstrated a through-substrate-via process, which is last hurdle in GaN/Diamond manufacturing technology. To fully exploit Diamond's superior thermal property for GaN HEMT devices, we include Aluminum Nitride (AlN) barrier in epitaxial layer structure, in addition to conventional Aluminum Gallium Nitride (AlGaN) barrier layer. The current collapse revealed very stable up to Vds = 90 V. The trapping behaviors were measured Emission Microscope (EMMI). The traps are located in interface between Silicon Nitride (SiN) passivation layer and GaN cap layer.