대형 립 폴리머 광도파로 브래그 격자를 이용한 두 파장 레이저

성치훈,김준휘,신진수,오민철,Sung, Chi-Hun,Kim, Jun-Whee,Shin, Jin-Soo,Oh, Min-Cheol 한국광학회 2014 한국광학회지 Vol.25 No.1

두 파장 레이저를 구현하기 위해서 폴리머 광도파로 브래그 격자와 초발광 LED로 구성된 외부 공진 구조의 레이저를 제작하였다. 대형 립(oversized rib) 구조의 광도파로와 폴리머 광도파로 브래그 격자는 각각 유효굴절률법과 전송행렬법을 이용하여 설계하였으며, 서로 다른 격자 주기를 가지는 폴리머 광도파로 브래그 격자는 이중 노광 레이저 간섭법을 이용하여 제작하였다. 브래그 격자의 반사율 변화에 따른 외부 공진 레이저의 특성을 보기 위해 2 mm의 고정된 길이를 가지며 537 nm의 주기를 갖는 브래그 격자와 0.5 mm에서 6 mm까지 여러 가지 길이를 가지며 540 nm의 주기를 갖는 브래그 격자를 제작하였다. 격자 주기가 537 nm와 540 nm인 브래그 격자의 길이가 각각 2 mm와 2.2 mm일 때 제작된 두 파장 레이저는 1554 nm 파장과 1564 nm 파장에서 0 dBm에 가까운 출력 파워를 보이며, 45 dB이상의 SMSR(side mode suppression ratio)와 0.2 nm의 20-dB 대역폭 특성을 가짐을 확인하였다. An external cavity laser supporting two wavelengths is demonstrated by incorporating polymer waveguide Bragg reflectors and a superluminescent light-emitting diode. An oversized rib waveguide structure and Bragg gratings are designed by using the effective-index and transmission-matrix methods. Bragg gratings with different periods are inscribed on a polymer waveguide through double-exposure laser interferometry. In order to tune the cavity loss affected by the reflectivity of Bragg gratings, a Bragg reflectors with varying length is incorporated. Two-wavelength-mode lasing is achieved for the device consisting of 2-mm long, 537-nm period gratings and 2.2-mm long, 540-nm period gratings; the lasing wavelengths are 1554 nm and 1564 nm, with an output power close to 0 dBm, a 20-dB bandwidth of 0.2 nm, and a side-mode suppression ratio of 45 dB.

NAFNet을 활용한 RGBW/RGB Color Filter Array 리모자이크 및 디노이즈

성치훈(Chi-Hun Sung),김성열(Seong-Yeol Kim),손승원(Seung-Won Son),신호주(Ho-Ju Shin),김승욱(Seung-Wook Kim) 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6

Raw-image-based image processing and computer vision algorithms usually adopt RGB Bayer patterns. Consequently, an effective approach to make the most existing image processing and computer vision tasks is to use a preprocessing method that converts other color filter arrays (CFAs) to RGB Bayer patterns. In particular, deep learning-based methods should be used to ensure the arrangement structure and image quality of an RGBW CFA. In this paper, we present a data preprocessing method that can produce high-quality RGB Bayer patterns. Extensive experimental results show that the proposed method outperforms conventional U-Net-based methods in terms of PSNR values.

한국정당의 국민참여경선제 도입 적실성과 보완점: `제도`와 `유권자문화`를 중심으로

성치훈 ( Sung Chihoon ),진영재 ( Jin Youngjae ) 한국의회발전연구회 2016 의정연구 Vol.22 No.3

2002년 이후 한국의 주요 정당들은 공직선거 후보선출을 비롯한 당내 선거에 국민참여경선제를 도입했다. 본 논문의 목적은 지금까지 실시된 국민참여경선제의 적실성 여부를 제도와 유권자문화의 적합성을 통해 살펴보고, 이를 바탕으로 한국의 정치상황과 유권자문화에 맞는 더 좋은 형태의 `한국형 국민참여경선제`를 제안하는 것에 있다. 이를 위해 본 논문은 2002년 이후 주요 정당의 대통령 선거, 국회의원 선거, 전당대회에서 실시된 다양한 형태의 국민참여경선제를 정리하고 제도 도입과정에서 유권자 문화와의 차이 속에서 발생한 여러 문제점들을 정리할 것이다. 마지막으로 본 논문은 이러한 문제점들을 바탕으로 `한국형 국민참여경선제`를 위한 실질적 제언들을 다음과 같이 하고자 한다. 이는 제도적 친숙성을 높이기 위한 국민참여경선제의 부분적 도입, 정당들의 당원 권한 확보와 모바일 등을 비롯한 온라인 플랫폼을 활용한 정당정치강화 노력, 신뢰성이 담보되기 전까지 여론조사 방식의 축소, 여성대표성 확보를 위한 제도적 보완 등이다. 이 제안들은 단기적 제안이 아닌 중·장기적 제안이 될 것이며 이러한 현실적인 제안들이 한국정치의 고질적 문제인 정당공천의 문제점들에 대한 해결책이 될 것이다. Since 2002, Korean political parties have partially brought the rule of `open primary system` for candidate nominations. This manuscript seeks to understand whether the adoption of the open primary systems is appropriate for the Korean political circumstances or not, explaining it mainly with the changes of both institutions and voting behaviors. The research question is concerned with and summarized into two things: one is to evaluate the various kinds of open primary systems from the standpoint of empirical appropriateness to Korean political environment; another is to propose the better form of open primary systems based on the actual function of Korean politics. In order to do so, the authors do literature reviews with regard to the grasping the discussion points of Korean open primary systems. Secondly, we deal with the five aspects above in both Presidential Elections and National Assembly Elections from 2002 up to now. Consequently, the paper suggests practical programs for candidate nomination process. Presumably, this kind of proposal would be mid- or long-term perspectives rather than short-term ones.

냉난방 가동 모사에 따른 콘크리트 에너지파일의 열응력 해석에 대한 연구

성치훈(Chihun Sung),박상우(Sangwoo Park),김병연(Byungyeon Kim),정경식(Kyoungsik Jung),최항석(Hangseok Choi) 한국지열·수열에너지학회 2015 한국지열에너지학회논문집 Vol.11 No.2

The energy pile, used for both structural foundations and heat exchangers, brings about heat exchange with the ground formation by circulating a working fluid for heating and cooling buildings. As heat exchange occurs in the energy pile, thermal stress and strain is generated in the pile body and surrounding ground formation. In order to investigate the thermo-mechanical behavior of an energy pile, a comprehensive experimental program was conducted, monitoring the thermal stress of a cast-in place energy pile equipped with five pairs of U-type heat exchanger pipes. The heating and cooling simulation both continued for 30 days. The thermal strain in the longitudinal direction of the energy pile was monitored for a 15 operation days and another 15 days monitoring followed, without the application of heat exchange. In addition, a finite element model was developed to simulate the thermomechanical behavior of the energy pile. A non-linear contact model was adopted to interpret the interaction at the pile-soil interface, and thermal-induced structure mechanics was considered to handle the thermo-mechanical coupled multi-field problem.

Application of Block-centered Finite Difference Formulation for Non-linear Finite Strain Consolidation

이동섭,성치훈,이철호,최항석 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.7

A one-dimensional block-centered finite-difference model has been developed to estimate the rate of non-linear finite strain consolidation. The governing equations including the hydrodynamic and constitutive equations are presented. The hypothesis of the uniqueness of the End-of-Primary (EOP) void ratio – effective stress relationship is adopted to calculate the primary consolidation settlement. The explicit block-centered finite difference formulations and boundary conditions are presented and discussed. The developed model was compared with a point-centered finite-difference program, ILLICON to show the efficiency of the block- centered model. The block-center model provides an efficient tool to deal with interface boundaries and has advantageous ability to take into consideration the time-dependent loading, layered soil systems, and variable soil properties.

대구경 현장타설 에너지파일의 열교환 성능과 시공성 및 경제성분석

박상우,성치훈,이동섭,정경식,최항석 한국지반공학회 2015 지반 : 한국지반공학회지 Vol.31 No.7

적대적 생성 신경망을 이용한 컬러 필터 배열 변환 기법

김성열,성치훈,김승욱 한국통신학회 2024 韓國通信學會論文誌 Vol.49 No.4

서로 다른 카메라 센서에서 동일한 장면을 촬영한정렬된 컬러 필터 배열의 수집이 어렵기 때문에, 관련 데이터셋은 충분한 학습 데이터를 제공하지 못하는 경우가 많다. 본 논문에서는 RGBW와 RGB 컬러필터 배열 변환을 위해 적대적 생성 신경망을 사용하는 새로운 데이터 증강 및 학습 기법을 제안한다. 제안하는 기법은 추가적인 데이터 수집 작업 없이 향상된 컬러 필터 배열의 변환 성능을 보인다. The lack of paired data is a critical problem in raw image mapping since it is hard to capture the color filter arrays (CFAs) of the same scene from different cameras. This paper introduces a novel RGBW/RGB CFA data generation method using generative adversarial networks (GANs). The experimental results confirm that the performance of the RGBW-to-RGB CFA mapping can be improved by using the proposed data generation method based on GANs.

대구경 현장타설 에너지파일의 열교환 성능과 시공성 및 경제성 분석

박상우,최항석,성치훈,이동섭,정경식 한국지반공학회 2015 한국지반공학회논문집 Vol.31 No.5

An energy pile is a novel type of ground heat exchangers (GHEX’s) which sets up heat exchange pipes inside apile foundation, and allows to circulate a working fluid through the pipe for exchanging thermal energy with thesurrounding ground stratum. Using existing foundation structure, the energy pile can function not only as a structuralfoundation but also as a GHEX. In this paper, six full-scale energy piles were constructed in a test bed with variousconfigurations of the heat exchange pipe inside large-diameter cast-in-place piles, that is, three parallel U-type heatexchangers (5, 8 and 10 pairs), two coil type heat exchangers (with a 500 mm and 200 mm pitch), and one S-typeheat exchanger. During constructing the energy piles, the constructability of each energy pile was evaluated withconsideration of the installation time, the number of workers and any difficulty for installing. In order to evaluate thethermal performance of energy piles, the thermal performance tests were carried out by applying intermittent (8 hoursoperating-16 hours pause) artificial cooling operation to simulate a cooling load for commercial buildings. Through thethermal performance tests, the heat exchange rates of the six energy piles were evaluated in terms of the heat exchangeamount normalized with the length of energy pile and/or the length of heat exchange pipe. Finally, the economicfeasibility of energy pile was evaluated according to the various types of heat exchange pipe by calculating demandedexpenses per 1 W/m based on the thermal performance test results along with the market value of heat exchange pipesand labor cost.

병렬 U형 현장타설 에너지파일의 열교환 효율 및 적용성 평가

박상우,김병연,성치훈,최항석,Park, Sangwoo,Kim, Byeongyeon,Sung, Chihun,Choi, Hangseok 대한토목학회 2015 대한토목학회논문집 Vol.35 No.2

에너지파일은 기존의 수직밀폐형 지중열교환기를 경제적으로 대체할 수 있는 새로운 형태의 지중열교환기이다. 즉, 에너지파일은 건물의 기초 구조물과 지중열교환기의 역할을 동시에 수행하는 에너지 구조체로서, 말뚝 기초 내부에 열교환 파이프를 삽입하고 파이프를 통해 유체를 순환시켜 지반과의 열교환을 유도한다. 본 연구에서는 병렬 U형(5쌍, 8쌍, 10쌍)의 열교환 파이프를 대구경 현장타설 에너지파일에 삽입하여, 3본의 에너지파일을 실규모로 시공하였다. 또한 현장 열응답 시험(In-situ thermal response tests, TRTs)을 수행하고 시공된 현장타설 에너지파일과의 열교환 효율을 비교하기 위하여 30m 깊이의 수직밀폐형 지중열교환기를 별도로 시공하였다. 병렬 U형 현장타설 에너지파일에 대해서는 냉난방 부하를 인공적으로 주입하는 열교환 성능 평가시험을 수행하여 열교환 성능(heat exchange rate)을 평가하였다. 마지막으로 현장타설 에너지파일의 적용성 평가를 위해 산정된 상대 열교환 효율(relative heat exchange efficiency) 및 열교환 성능을 선행 연구 결과와 비교하였으며, 본 연구에서 시공된 현장타설 에너지파일은 안정적이고 효율적인 열성능을 보이는 것으로 나타났다. An energy pile is one of the novel ground heat exchangers (GHEX's) that is a economical alternative to the conventional closed-loop vertical GHEX. The combined system of both a structural foundation and a GHEX contains a heat exchange pipe inside the pile foundation and allows a working fluid circulating through the pipe, inducing heat exchange with the ground formation. In this paper, a group of energy piles equipped with parallel U-type (5, 8 and 10 pairs) heat exchange pipes was constructed in a test-bed by fabricating in large-diameter cast-in-place concrete piles. In addition, a closed-loop vertical GHEX with 30m depth was constructed nearby to conduct in-situ thermal response tests (TRTs) and to compare with the thermal performance of the cast-in-place energy piles. A series of thermal performance tests was carried out with application of an artificial cooling and heating load to evaluate the heat exchange rate of energy piles. The applicability of cast-in-place energy piles was evaluated by comparing the relative heat exchange efficiency and heat exchange rate with preceding studies. Finally, it is concluded that the cast-in-place energy piles constructed in the test-bed demonstrate effective and stable thermal performance compared with the other types of GHEX.

차세대 지능형 소자 구현을 위한 모노리식 3D 집적화 기술 이슈

문제현,남수지,주철웅,성치훈,김희옥,조성행,박찬우,Moon, J.,Nam, S.,Joo, C.W.,Sung, C.,Kim, H.O.,Cho, S.H.,Park, C.W. 한국전자통신연구원 2021 전자통신동향분석 Vol.36 No.3

Since the technical realization of self-aligned planar complementary metal-oxide-semiconductor field-effect transistors in 1960s, semiconductor manufacturing has aggressively pursued scaling that fruitfully resulted in tremendous advancement in device performances and realization of features sizes smaller than 10 nm. Due to many intrinsic material and technical obstacles, continuing the scaling progress of semiconductor devices has become increasingly arduous. As an effort to circumvent the areal limit, stacking devices in a three-dimensional fashion has been suggested. This approach is commonly called monolithic three-dimensional (M3D) integration. In this work, we examined technical issues that need to be addressed and overcome to fully realize energy efficiency, short latency and cost competency. Full-fledged M3D technologies are expected to contribute to various new fields of artificial intelligence, autonomous gadgets and unknowns, which are to be discovered.