Polarization Insensitive CWDM Optical Demultiplexer Based on Polarization Splitter-rotator and Delayed Interferometric Optical Filter

정석환,박혁,이준기 한국광학회 2023 Current Optics and Photonics Vol.7 No.2

We theoretically analyze and experimentally demonstrate a polarization-diversified four-channel optical demultiplexer (DeMUX) comprising a hybrid mode conversion-type polarization splitter rotator (PSR) and delayed Mach–Zehnder interferometer optical DeMUX for use in coarse wavelength division multiplexing (CWDM)-based optical interconnect applications. The Si wire-based device fabricated by a complementary metal-oxide semiconductor-compatible process exhibited nearly the same filter spectral response irrespective of the input polarization state under the PSR. The device had an extremely low insertion loss of <1.0 dB, polarization-dependent loss of <1.0 dB, and interchannel imbalance of <0.5dB, suppressing unwanted wavelength and polarization crosstalk from neighboring channels of <−20 dBat each peak transmission channel grid.

국가직무능력표준(NCS)의 운영 논리에 대한 교육적 고찰 -포스트모더니즘을 중심으로-

정석환,윤성일 동아인문학회 2019 동아인문학 Vol.48 No.-

The purpose of this study is to research National Competency Standards (NCS), which is being utilized in vocational education fields in Korea, applying perspectives of the post-modernism. Specifically, the theoretical background that NCS was introduced to Korean vocation education was studied and its validity has been discussed. The fundamental point of this study is that the perspective of the Ministry of Education who introduced NCS as an education policy is different from that of vocation education institutions(technical colleges or vocation colleges), which accommodated such policy to the field. Even though the Ministry of Education developed NCS in need of vocation education reflecting periodical changes, situation that the colleges who have to accommodate such policies to the education are at is very different. When ministry-operated and developed education program is being introduced to each college, it is related to the college accreditation conducted by the Ministry. Education programs developed and conducted by the Ministry is normally recognized as strict enforcement to the colleges and it is deeply related to the various college accreditation being connected to the instructions from the Ministry. As college accreditation is related to the financial support to the college, each college tends to take any instruction from the Ministry seriously. The post-modernism philosophy opposes to this kind of generality and uniformity of education policy. When perceived from the view of education philosophy based on the post-modernism, the current NCS can be regarded as a kind of violence. A direction to conduct the uniform education program based on the same criteria in every college is a force of the authority. The point of this study was to implicate that no matter how good the education program is, it is not right to conduct the policy in the name of the financial support. To conclude, a college should have a total autonomous judgement whether to accommodate the education program, NCS. 본 연구는 최근 고등직업교육의 일선에서 ‘현장중심 교육과정’이라는 명목으로 시행되고 있는 ‘국가직무능력표준(NCS)’의 도입과 운영의 논리를 비판적으로 고찰하였다. 구체적으로 NCS라는 하나의 교육체계가 직업교육의 현장에서 운영되는 과정 이면에 존재하는 ‘교육관련 기관’들과 ‘일선 대학’들의 관계에 내재한 ‘권력 관계’를 탐색해보았다. 본 연구를 시행하게 된 배경이자 논리적 가정은 ‘NCS’라는 직업교육과정이 하나의 시스템으로 정착되고 체계화되는 과정에서 교육관련 기관들로 구성된 ‘상위기관’과 단위 대학을 중심으로 한 ‘하위기관(종속기관)’ 사이에 모종의 ‘권력관계’가 존재한다는 것이다. 우리나라에서 도입・운영되고 있는 대부분의 교육정책들은 정책을 입안하고 시행하는 ‘상위기관’과 이를 따라야 하는 ‘하위기관’ 사이에 암묵적인 권력(복종)관계가 내재해 있다. 그리고 그 권력(복종)관계의 중심에는 소위 ‘재정지원’이라는 매력적인 당근이자 채찍이 존재하고 있는 것이다. 본 연구에서 논의의 대상으로 설정한 NCS의 운영 또한 상위기관이 정치적, 사회적, 경제적 논리에 입각해 실행을 추진하고, 하위기관들은 이에 맹목적으로 따르는 논리가 개입되고 있음을 밝혔다. 이러한 과정에서 대학들의 구성원들은 연구, 학생지도, 사회봉사 등의 주요한 업무를 뒤로하고 상위기관이 제시한 지표에 따라 각종 평가보고서를 작성하는 업무에 우선적으로 매진하게 된다. 본 연구는 우리나라 교육정책의 도입과 실행과정에서 고질적인 병폐로 지적되어 온 상명하복, 관료주의적, 비민주적 정책운영의 문제점이 NCS의 도입과 운영과정에도 엄연히 존재함을 밝히고 있다. 그리고 그러한 문제점을 해결할 논리적 단초를 포스트모더니즘에서 찾고자 했다. 포스트모더니즘은 모든 ‘전체성’과 ‘통일성’에 반대하는 사상적 조류로 ‘모든 전체성은 폭력’이라는 입장이다. 포스트모더니즘이 지향하는 ‘작은 목소리의 존중’, ‘다른 언어게임 법칙에 대한 인정’, ‘차이에 대한 인내와 배려’ 등의 원리가 NCS 운영이라는 현실에 적용될 때 비로소 바람직한 직업교육의 방향이 열릴 수 있을 것으로 기대한다.

경요골 동맥 관상동맥 조영술 시 생긴 이상성 우측 빗장밑 동맥의 합병증 1예

정석환,금동성 대한내과학회 2011 대한내과학회지 Vol.80 No.-

Right transradial coronary catheterization is very popular and performed by many clinicians with few complications. An aberrant right subclavian artery (arteria lusoria) arising from the descending thoracic aorta is an uncommon congenital variant. Here, we present the case of a patient with an aberrant right subclavian artery dissection after right transradial coronary catheterization, which is a rare complication. We diagnosed the complication by chest CT, which showed the dissection of the aberrant right subclavian artery. Dissection of an aberrant right subclavian artery is a rare complication of right transradial coronary angiograph. (Korean J Med 2011;80:S157-S160) 우측 요골 동맥을 이용한 관상동맥 조영술은 환자의 편이성 등 여러 가지 장점 때문에 많이 시행되는 술식이다. 그러나 여러 장점에도 불구하고 우측 요골 동맥을 이용한 관상동맥 조영술에 따르는 여러 가지 합병증 역시 있을 수 있다. 이상성 우측 빗장밑 동맥을 가진 환자의 경우 이로 인한 시술상의 어려움, 시술의 실패 등은 잘 알려져 있으나, 시술 후에 생긴 우측 빗장밑 동맥 박리는 많이 알려져 있지 않다. 본 증례는 흔하지 않은 합병증을 경험했기에 이에 대한 증례 보고를 하는 바이다.

정수장 고효율 혼화 장치 자동제어 시스템 개발

정석환 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

Inability of Mate and Species Recognition by Male Asian Toads, Bufo gargarizans

정석환,박시룡,성하철 한국통합생물학회 2008 Animal cells and systems Vol.12 No.2

In recent years, we frequently observed miss-matched pairs between male Asian toads, Bufo gargarizans,and bullfrogs, Rana catesbeiana , at the toad breedingponds, where scramble competition for mating occurredamong the male toads. Thus, we performed two-choiceexperiments to investigate recognition ability of mates andspecies in male toads. The test males did not discriminatesexes, but the clasped stimulus males imediatelyproduced release calls and stopped it while the claspednot discriminate reproductive state of females and evenspecies. However, male toads chose larger individuals. Thepresent results indicate that the main reason of miss-matched amplexus by the male toads is due to 1) the lack ofrecognition cues of conspecifics, 2) the lack of comunicationtools like release calls, and 3) the larger size of bullfrogsthan male toads themselves.

로이유리의 저방사 코팅 적용 위치에 따른 실내 온도변화 및 에너지 성능 비교 분석

정석환,김성우,박상현,이종찬,임정희,김병선 대한건축학회 2007 대한건축학회논문집 Vol.23 No.8

In the high oil prices age, intensification of energy efficiency promotion in the building sector is required. Windows are dominating large percentage whole building loads and are regarding as the primary target of energy efficiency. The purpose of this study is to improve energy efficiency of windows in high-rise residential buildings through the evaluation of their indoor temperature change & heating and cooling energy consumption. Analysis of Indoor temperature change and building energy consumption was performed through the use of simulation programs EnergyPlus and Window. The process of this study is as follows. First, In each case, estimated indoor temperature change, window heat gain and window heat loss. Then, the annual heating and cooling energy consumption according to the different glazing types are compared one another. The results show that the application of Low-E coating applying in the outside glazing can substantially increase the energy performance.

Skeletochronological Age Determination and Comparative Demographic Analysis of Two Populations of the Gold-spotted Pond Frog (Rana chosenica)

정석환,박대식,성하철,이정현,박시룡 한국생태학회 2007 Journal of Ecology and Environment Vol.30 No.1

To obtain demographic information on threatened gold-spotted pond frog (Rana chosenica Okada,1931) populations, we determined the ages of 45 male and 13 female frogs (20 males and 9 females from Cheongwon and 25 males and 4 females from Tae-an) and compared the age structures and growth patterns of the two populations in 2006. The snout-vent length (SVL) and body weight of female frogs were greater than 3 to 6 years old. In both populations, 4 years old male frogs were the most abundant age-sex class. The age structures of the two populations were significantly different and the growth coefficients of male frogs from the Cheongwon population were greater than those from the Tae-an population. The mean age of males from the Tae-an population was higher than that from the Cheongwon population. However, the SVL and body weights of male frogs were not different between two populations and there was no difference between the two populations in the mean male SVL at any age. The results could increase our understanding of the life-history of this threatened frog and may be useful in conservation planning.

소형 로봇 시스템을 위한 새로운 줄 꼬임 구동 메커니즘 설계 및 제어

정석환,김경수 제어로봇시스템학회 2018 제어로봇시스템학회 국내학술대회 논문집 Vol.2018 No.5

Initial Experience of Retrograde Wire Approach in Coronary Chronic Total Occlusion Intervention

정석환,김무현,Long Hao Yu,김경호,금동성,박태호,차광수,김영대,Jong Sung Park 대한심장학회 2009 Korean Circulation Journal Vol.39 No.6

Background and Objectives: Retrograde wire approach has been emerged as a useful tool to enhance success rate in coronary chronic total occlusion (CTO) intervention. Therefore, we tried to report the initial experience of retrograde approach and its clinical implication on CTO intervention. Subjects and Methods: From February 2007 to July 2008, retrograde approaches were performed in 28 patients with 31 CTO lesions out of 61patients. A hydrophilic coated guidewire was inserted by using microcatheter or over-the-wire (OTW) balloon through the collateral channel (septal or epicardial artery) via several strategies. Results: Mean age of patients was 63.4± 11.6 years. Male and female were 20 and 8 patients, respectively. The target artery with CTO lesions included the right coronary artery (45.2%), the left anterior descending artery (51.6%), and the left circumflex artery (3.2%). The mean length of CTO lesion was 18.4±16.4 mm. Overall technical success rate was 64.5%. The success rate of primary attempt was 78.9%, while the success rate of immediate and secondary attempt was 41.7%. Collateral channel dissections were observed in 3 patients and no patients among these patients developed cardiac tamponade. One patient had a silent non-Q wave myocardial infarction (MI) after the procedure. One failed patient died suddenly 3 days after the procedure. After percutaneous coronary intervention (PCI) procedure, no case was performed target vessel revascularization (TVR), urgent coronary artery bypass graft (CABG), and urgent PCI. Conclusion: Retrograde approach is an evolving technique to improve the success rate of CTO intervention. After the learning curve period, this technique could be the useful tool to enhance success rate in CTO intervention. Background and Objectives: Retrograde wire approach has been emerged as a useful tool to enhance success rate in coronary chronic total occlusion (CTO) intervention. Therefore, we tried to report the initial experience of retrograde approach and its clinical implication on CTO intervention. Subjects and Methods: From February 2007 to July 2008, retrograde approaches were performed in 28 patients with 31 CTO lesions out of 61patients. A hydrophilic coated guidewire was inserted by using microcatheter or over-the-wire (OTW) balloon through the collateral channel (septal or epicardial artery) via several strategies. Results: Mean age of patients was 63.4± 11.6 years. Male and female were 20 and 8 patients, respectively. The target artery with CTO lesions included the right coronary artery (45.2%), the left anterior descending artery (51.6%), and the left circumflex artery (3.2%). The mean length of CTO lesion was 18.4±16.4 mm. Overall technical success rate was 64.5%. The success rate of primary attempt was 78.9%, while the success rate of immediate and secondary attempt was 41.7%. Collateral channel dissections were observed in 3 patients and no patients among these patients developed cardiac tamponade. One patient had a silent non-Q wave myocardial infarction (MI) after the procedure. One failed patient died suddenly 3 days after the procedure. After percutaneous coronary intervention (PCI) procedure, no case was performed target vessel revascularization (TVR), urgent coronary artery bypass graft (CABG), and urgent PCI. Conclusion: Retrograde approach is an evolving technique to improve the success rate of CTO intervention. After the learning curve period, this technique could be the useful tool to enhance success rate in CTO intervention.

A Model for Midlife Pastoral Counseling

정석환 한국기독교학회 2006 한국기독교신학논총 Vol.48 No.-