당화혈색소(HbA1)의 임상적 응용

윤성현,박태현,김목현 대한당뇨병학회 1983 Diabetes and Metabolism Journal Vol.7 No.1

원형 자동 문합기 치핵절제술의 임상적 유용성

윤성현,민병소,강중구 대한대장항문학회 2004 Annals of Coloproctolgy Vol.20 No.1

Purpose: The circular stapled hemorrhoidectomy established by A. Longo involves reducing the mucous membrane prolapse and blocking the end branches of the upper hemorrhoidal artery through transverse incision of a suitable section of the mucosa between the rectum and the anal canal. This study was undertaken to determine the efficacy and the safety of a circular stapled hemorrhoidectomy by comparing it with a conventional Milligan-Morgan hemorrhoidectomy. Methods: One hundred thirty (130) patients with prolapsed hemorrhoids underwent surgical treatment with either a conventional (n=66)(conventional group) or a circular stapled (n=64) (stapled group) hemorrhoidectomy. The operation time was recorded, and the resected specimen was examined. The patients assessed their postoperative pain. Time to first bowel movement, hospital stay, and postoperative complications were analyzed. All patients received follow-up examinations at the out-patient clinic, and the time to return to work and the degree of their satisfaction were checked. Results: The stapled group had a shorter average operation time (19.2 min. vs 26.1 min., P=0.016). The postoperative pain score in the stapled group was significantly lower than it was in the conventional group (P<0.05). Time to first bowel movement and hospital stay were not significantly different between the groups. Return to work was significantly faster in the stapled group (6.5 days vs 15.8 days, P<0.05). The degrees of satisfaction for the two groups were similar, and postoperative complications in the two groups were both similar and acceptable (6.1% vs 11.0%, P>0.05). Conclusions: A circular stapled hemorrhoidectomy offers a significantly less painful alternative to the conventional technique and is associated with an earlier return to normal activity. However, the long-term outcome needs to be evaluated further.

스마트계약 기반 회의용 키 분배 기법

윤성현,Yun, Sunghyun 한국사물인터넷학회 2020 한국사물인터넷학회 논문지 Vol.6 No.4

최근 코로나 19 확산으로 비대면 화상회의에 대한 수요가 급증하고 있다. 기존의 줌, 구글 미트와 같은 서버-클라이언트 기반의 화상회의 시스템에서 서버는 회의키를 이용하여 회의 멤버 및 회의 내용을 제어한다. 만약 서버를 신뢰할 수 없다면 서버에 의한 조작 및 부정이 가능하기 때문에 회의 멤버들의 프라이버시는 보장되지 않는다. 따라서, 서버의 도움 없이 모든 참여자가 신뢰할 수 있는 회의키 생성 및 분배 기법의 개발이 필수적이다. 스마트계약은 블록체인에 저장되는 프로그램으로 블록체인의 특성상 수정될 수 없고 누구나 그 실행 결과를 검증할 수 있다. 본 논문에서는 스마트계약 기반의 회의용 키 분배 기법을 제안한다. 제안한 방법은 키 분배를 위한 스마트계약 발행, 회의키 생성 및 검증 단계로 구성된다. 스마트계약은 기존의 신뢰할 수 있는 서버의 역할을 대체하며, 회의 멤버들은 스마트계약에 구현된 프로토콜에 따라서 회의키를 생성한다. 제안한 방법은 화상회의 시스템에 적용할 수 있으며, 회의 멤버 이외의 다른 사용자들은 회의키에 접근할 수 없다. Recently, epidemic of covid-19 causes rapid increase in demand for untact video conferences. In existing server-client based video conference systems such as Zoom, Google Meet, etc., the server generates the conference key and controls the access rights of meeting members and their contents with it. In this case, the server can fabricate or repudiate the meeting. So, the privacy of the meeting members is not guaranteed. It's necessary to make the conference key distribution scheme where all participants can verify the trustfulness without help of the server. The smart contract is the program stored to the blockchain. Its contents cannot be altered due to the property of the blockchain, and everybody can verify the execution results of it. In this study, we propose the smart contract based conference key distribution scheme. The proposed scheme is consisted of smart contract deployment, conference key generation and verification stages. The smart contract replaces the role of existing trustful server and the meeting members can generate the conference key according to the protocols implemented on it. The proposed scheme can be applied to the video conference systems and only the meeting members can access the conference key.

군용항공기 부품인증제도 구축에 관한 연구

윤성현,안영갑,김창영,박동기 한국항공우주학회 2010 한국항공우주학회 학술발표회 논문집 Vol.2010 No.11

ORDBMS 기반 시공간 질의 확장의 설계 및 구현

윤성현,남광우 한국지리정보학회 2003 한국지리정보학회지 Vol.6 No.4

이 논문은 객체관계형 데이터베이스 시스템의 객체지향적 특성인 추상데이터타입과 속성 및 연산의 상속성을 이용하여 구현가능한 시공간 질의 확장에 대하여 기술한다. 실세계의 공간 객체는 시간상에서 변화한다. 시공간 데이터베이스는 이러한 객체의 이력을 위해 공간 차원뿐만 아니라 시간차원을 관리하는 것을 지원한다. 제시된 시공간 데이터베이스는 공간 및 시간 차원을 각각 최상위 클래스로 구성하고, 시공간 클래스들은 이 클래스들을 상속 및 확장하여 구현되었다. 이 연구에서 수행된 시공간 데이터베이스를 위한 시간과 공간 확장은 기존 시스템에서 시공간 데이터베이스 시스템으로 전환을 용이하게 할 뿐 아니라 새로운 시공간 데이터베이스의 지원을 위한 기존 데이터베이스의 변경을 필요하지 않은 장점을 갖는다. In the paper, we describe the query extension techniques for spatiotemporal query functionalities on object-relational DBMS. The spatial objects in real world change the shapes over time. Spatiotemporal databases support to manage a temporal dimension as well as a spatial dimension for history of the objects. The proposed techniques can make conventional object-relational databases to support spatiotemporal databases system by the implementation and inheritance of abstract data types. We define and implement spatial and temporal classes as superclass. And, spatiotemporal classes inherits and extends the classes. The proposed extensions make it easy that conventional database systems not only are transformed into the spatiotemporal database systems, but also do not need to be changed to support spatiotemporal application.

애자일 방법론을 적용한 무기체계 연구개발 사업관리 절차 개선 연구

윤성현 한국IT서비스학회 2019 한국IT서비스학회 학술대회 논문집 Vol.2019 No.-

A Case of Saponated Cresol Ingestion which Led to Altered Mentality, Chemical Dermal Burn, and Liver Toxicity

윤성현,백진휘,정현민,김지혜,김준식,한승백 대한응급의학회 2014 大韓應急醫學會誌 Vol.25 No.1

Saponated cresol solutions are common household disinfectantsworldwide. Their main component, concentrated cresol,is extremely toxic and fatal; however, precise information onthe clinical manifestations of cresol intoxication is not available. We report on a case of suicidal poisoning by ingestionof saponated cresol. A 63-year-old male presented withunconsciousness and brownish discoloration on the neckand anterior chest wall after ingesting 100 ml of 50%saponated cresol solution with suicidal attempt. The patientshowed a wide range of clinical features of cresol intoxication,including decreased consciousness, respiratory distress,strong carbolic acid odor, dark brown urine, and chemicaldermal burns on multiple areas. General treatment of cresolintoxication is intensive supportive care. In addition, reducingsystemic absorption is most important in patients with cresolintoxication who present with cresol burns. Because the rateof cresol absorption through the skin is proportional to thesize of the area involved and the duration of contact of thechemical with the skin rather than to the concentration of thecresol solution, gross decontamination, including removal ofcontaminated clothing and vigorous flushing with water, isvery important. Quantitative assays for cresol and its metabolitesin blood or urine are needed in order to confirm the diagnosis. However, because these analytical methods are timeconsuming and are not routinely available in most emergencydepartments, the clinical manifestations of this casemay be useful in early diagnosis and treatment.

자발성 두개내 저압 환자와 경막천자 후 두통 환자군에서의 경막외 혈액 봉합술의 효과의 비교 및 고찰

윤성현,이준우,이근영,이영준,강흥식 대한영상의학회 2014 대한영상의학회지 Vol.70 No.4

Purpose: To evaluate and compare the effectiveness of fluoroscopy-guided epidural blood patch (EBP) in patients with post-dural puncture headache (PDPH) and spontaneous intracranial hypotension (SIH). Materials and Methods: Between August 2012 and September 2013, 16 patients (12 with PDPH, 4 with SIH; 5 males, 11 females; age range 19–58 years, mean age 32.8 years) who underwent EBP in the Department of Radiology were included in this study. Pain relief within three days after EBP was evaluated based on medical record and classified on a 3-level scale: complete relief; incomplete relief; and failure. Recurrence is defined as aggravated postural headache after three days. We evaluated and compared treatment outcome between PDPH and SIH, using Fisher’s exact test (considered as significant when p < 0.05). Results: In 12 PDPH patients, the EBP provided complete relief in 5 patients (41.7%), and incomplete relief in 7 patients (58.3%). In 4 SIH patients, the EBP provided complete relief in 1 patient (25%), and incomplete relief in 3 patients (75%). There was no significant difference (p = 0.511) of pain relief rate between PDPH and SIH. There was recurrence in 5 patients with PDPH and 1 patient with SIH. Five PDPH patients were retreated by EBP with incomplete relief. Conclusion: Fluoroscopy-guided EBP provides effective treatment of postural headache for both SIH and PDPH patients. 목적: 경막천자 후 두통과 자발성 두개내 저압 환자에서 투시장치(fluoroscopy) 유도하 경막외 혈액 봉합술의 치료 효과를 평가하고 비교하였다. 대상과 방법: 2012년 8월부터 2013년 9월까지 본원 영상의학과에서 경막외 혈액 봉합술이 시행된 환자 16명[남자 5명, 여자 11명, 평균연령 32.8세(19~58세)]의 의무기록을 후향적으로 분석하였다. 치료 후 3일째의 통증 정도를 완전 경감(complete relief), 불완전 경감(incomplete relief), 치료 실패(failure)로 나누어 평가하였다. 두통의 경감이 있으나, 다시 악화된 경우 재발(recurrence)로 정의하였다. 각 환자군의 치료효과를 Fisher’s exact test로 비교하였다. 결과: 경막천자 후 두통 환자 12명 중 5명에서(41.7%) 완전 경감을, 7명에서(58.3%) 불완전 경감을 보였고 자발성 두개내 저압 환자 4명 중 1명에서(25%) 완전 경감을, 3명에서(75%) 불완전 경감을 보였다. 두 군 사이의 치료효과는 통계적으로 유의하게 다르지 않았다(p = 0.511). 불완전 경감 환자들 중 경막천자 후 두통 환자 5명(41.7%), 자발성 두개내 저압 환자 1명에서(25%) 재발하였고 경막천자 후 두통 환자 5명에서 경막외 혈액봉합술을 재시행하여 최종적으로 불완전 경감 상태로 퇴원 가능하였다. 결론: 경막천자 후 두통 환자와 자발성 두개내 저압 환자 모두에서 투시장치 유도하 경막외 혈액 봉합술을 통해 체위성 두통의 치료를 효과적으로 할 수 있다.

Methods for Determining the Monodispersity in a Cobalt Ferrofluid

윤성현,김병호,윤창선,차덕준 한국물리학회 2011 새물리 Vol.61 No.12

Particle size distributions in monodispersed cobalt ferrofluids are analyzed based on both dc and ac magnetic measurements. Modified log-normal distributions are proposed for fitting the experimental results, which properly accounts for the narrow distributions. The calculated average particle sizes are in good agreement with the transmission electron microscopy results. However, the ac method gives a much narrower distribution width than the dc magnetization curve fit. The proposed measurements, combined with analysis methods, are useful for characterizing ferrofluids being considered for biomedical applications.

Determination of the Temperature Dependence of the Magnetic Anisotropy Constant in Magnetite Nanoparticles

윤성현 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.5

The temperature dependence of the effective magnetic anisotropy constant, K(T), of Fe_3O_4 (magnetite)nanoparticles is obtained based on SQUID (superconducting quantum interference device)magnetometry. The variation of the blocking temperature, T_B, as a function of particle radius, r, is first determined by associating the particle size distribution and the anisotropy energy barrier distribution deduced from the hysteresis curve and from the magnetization decay curve, respectively. Finally, the magnetic anisotropy constant at each temperature is calculated from the relation between r and T_B. The resultant effective magnetic anisotropy constant K(T) decreases markedly with increasing temperature from 5.9 × 10^5 J/m^3 at 5 K to 1.1 × 10^4 J/m^3 at 280 K.