BMS 수리모형하에서 시스템의 수리효과 및 고장강도함수의 모수추정

윤원영,정석주,정일한,김종운,정상욱 한국경영과학회 2000 韓國經營科學會誌 Vol.25 No.4

Estimation problems of parameters of the failure process and the repair effect in repairable systems are considered. We propose estimation procedures in repairable systems without preventive maintenances. The fallure process is modeled by a proportional age reduction model (Brown. Mahoney, Sivazlian [5]) which is able to consider both aging and repair effects. Maximum likelihood method is used to estimate the repair effect and parameters of intensity function simultaneously. Simulations are performed to evaluate the accuracy of estimators. A numerical example is also presented.

에탄올의 광분해를 위한 TiO_2 촉매의 제조변수 고찰

김동일,이병용,김성욱,정석진 경희대학교 산학협력기술연구원 2000 산학협력기술연구논문집 Vol.6 No.-

In this study, TiO2, the popular photocatalyst, was used to decompose ethanol. TiO2 was prepared by the sol-gel method and coated on pyrex stick. A 15W, UV-A lamp was used as the UV light resource and a gas chromatography(HP 5890) was used to confirm the concentrations of ethanol, CO2 and the intermediate. Variation of preparation parameters and calcination temperature for TiO2 photocatalysts in the sol-gel method caused changes of ethanol decomposition activity. Ethanol photodecomposition activity was maximum when 0.14mol of HCl, 8mol of ethanol and 1.3mol of TTIP were mixed and calcinated at 500℃ for 3 hours. Acetaldehyde was detected as an intermediate and decomposed to carbon dioxide and water at the end of the reaction. Key words : TiO2, Photocatalyst, Sol-Gel method, VOCs

Temporal & Spatial Variations of Groundwater Quality in Hanlim, Jeju island

정성욱(Sung-Wook Choung),우남칠(Nam-Chil Woo),이광식(Kwang-Sik Lee) 대한지질학회 2004 지질학회지 Vol.40 No.4

Outcomes of Various Surgical Procedures on Acquired Lower Eyelid Epiblepharon in Thyroid Associated Ophthalmopathy

( Sung Wook Park ),( Nam Ju Kim ),( Ho Kyung Choung ),( Sang In Khwarg ) 대한안과학회 2012 Korean Journal of Ophthalmology Vol.26 No.5

Purpose: To report the outcomes of acquired lower eyelid epiblepharon after various surgeries in thyroid associated ophthalmopathy (TAO) patients. Methods: A retrospective review of the medical records of 53 TAO patients with acquired lower eyelid epiblepharon between October 1999 and June 2011 was performed. Data were collected on demographics, type of lower eyelid epiblepharon, the detailed surgical history such as orbital decompression, retraction repair, or epiblepharon repair and surgical outcomes including follow-up period, recurrence of epiblepharon, and postoperative complications. Results: Among the 53 TAO patients with acquired lower eyelid epiblepharon, 25 eyes of 17 patients underwent surgical management; 6 eyes of orbital decompression, 1 eye of orbital decompression followed by retraction repair, 2 eyes of orbital decompression followed by epiblepharon repair, 6 eyes of lower eyelid retraction repair, and 10 eyes of epiblepharon repair. Twenty two lower eyelid epiblepharons (88%) were resolved after final surgical treatment without complication during mean 16.2 months (SD, ±29.9 months) of follow up period; three of 6 epiblepharons that remained after orbital decompression underwent subsequent surgical management of retraction repair or epiblepharon repair, and epiblepharons were well-corrected. Mean amount of lower eyelid retraction was decreased from 1.68 mm (SD, ±1.17 mm) to 0.29 mm (SD, ±0.44 mm) after surgery, regardless of the type of surgery (n = 25, p < 0.000, Wilcoxon signed rank test). Conclusions: Acquired lower eyelid epiblepharon of TAO should be managed sequentially according to the general serial order of surgical managements in TAO; orbital decompression, correction of lower eyelid retraction and epiblepharon repair. Acquired lower eyelid epiblepharon was well resolved after surgical management in consecutive order, especially after repair of the lower eyelid retraction with a graft, or lower eyelid epiblepharon repair. Decreased lower eyelid retraction with a resolution of epiblepharon after surgery implied that lower eyelid retraction was associated with lower eyelid epiblepharon.

성인에서 발생한 소장의 Burkitt 림프종 1 예

이상우,김인선,김용식,이홍식,김창덕,진윤태,최재현,엄순호,류호상,전훈재,송치욱,현진해,허병원,정록선 대한소화기내시경학회 2001 Clinical Endoscopy Vol.22 No.6

Burkitt`s lymphoma is a rare disease that belongs to the aggressive non-Hodgkin`s lymphomas. Burkitt`s lymphoma usually occurs in children or younger persons. There is a strong association between endemic Burkitt's lymphoma and Epstein-Barr virus, whereas the association is weaker in the sporadic form occurring in Western countries. Burkitt`s lymphoma of the gastrointestinal tract occurring in adults has not been reported in Korea. We herein report an unusual case of Burkitt's lymphoma presenting with a palpable abdominal mass in a 52-year-old man infected with Epstein-Barr virus. A computed tomographic scan showed marked low density wall thickening of the terminal ileum. An endoscopy revealed a narrow lumen, shallow ulcerations, and irregular nodularity of the terminal ileum. Small bowel resection and hemicolectomy were performed and a histologic examination of the resected specimen confirmed the diagnosis. Six cycles of adjuvant chemotherapy were given and the patient has been doing well without evidence of recurrence.

한국 전립샘암 데이터베이스를 활용한 근치적 전립샘절제술 후 생화학적 재발 예측

유성혜 ( Sung Hye Yu ),최문주 ( Mun Joo Choi ),이선정 ( Sun Jung Lee ),김청수 ( Choung Soo Kim ),서성일 ( Seong Il Seo ),변석수 ( Seok Soo Byun ),정창욱 ( Chang Wook Jeong ),박용현 ( Yong Hyun Park ),홍준혁 ( Jun Hyuk Hong ),최인 한국보건정보통계학회(구 한국보건통계학회) 2019 한국보건정보통계학회지 Vol.44 No.1

Objectives: As the surgical techniques are developed such as adopting robotic surgery etc. It has been reduced postoperative side effects such as urinary incontinence and sexual dysfunction etc., but also remain constant risk of recurrence after the treatment. It is very important to figure out the predictive factors, whichincreasing the probability of long-term survival, by Analyzing the progression of the disease according to biochemical recurrence (BCR). This study aims to figure out the influential predictive factors on BCR by using Korean Prostate Cancer Registry (KPCR) database, which constructedwith providing data from Korean manifold, because of therecurrence-free survival rates are reported to vary according to geographical location and race. Methods: KPCR database consists 7,394 patients’ data which collected from six medical institutions, and final analysis was conducted with 5,119 patients’ data which collected from December 2003 to December 2014. Statistical analysis was conducted with the multivariable Cox proportional hazard regression models to figure out the correlation of clinical factors which affect BCR. The biochemical recurrence free survival rate (BCR-FS) was calculated using with Kaplan-Meier method. Results: The 5 year BCR occurred in 23.6% (1,209 patients). As a result of the recurrence rate, prostate specific antigen (PSA) value ≥20.1 ng/mL was 49.3%, the clinical T3 stage was 40.4%, Gleason score ≥8 was 54.4%, Gleason score 7 was 21.8%. The mean duration of BCR was 20.7 months and the strongest predictor of BCR was Gleason scoreand PSA value ≥20.1 ng/mL. Conclusions: It has been verified that, Gleason scores and PSA value are the most influential factors for biochemical recurrence after radical prostatectomy. These results will be helpful fordetermining the treatment direction in postoperative follow-up and able to contribute to improving survival outcome in the future.

과산화수소 보존표백시 Silicate 대체 약품에 관한 연구

이상헌,정성욱,김성권,류재홍,Michalowski, R J 한국공업화학회 1997 응용화학 Vol.1 No.2

This study was carried out to investigate the effect of the Versenate PS as the peroxide bleach stabilizer in peroxide bleaching system. Currently, but, most peroxide bleach systems contain peroxide, caustic to activate the peroxide, and the use of a stabilizer such as sodium silicate to stabilize the peroxide during the actual bleaching. Therefore, to evaluate he degree to replace sodium silicate, the experiments of metal signature analysis, metal control by chelant(DTPA), caustic level optimization, and the addition of Versenate PS peroxide stabilizer were performed. The results shows that the only combination of Versenate PS and low sodium silicate provide the most effective peroxide bleaching.

다기관 한국 전립샘 암 등록(KPCR) 데이터베이스를 이용한 근치적 전립샘 절제술의 수술 결과 비교

유성혜 ( Sung Hye Yu ),최문주 ( Mun Joo Choi ),김청수 ( Choung-soo Kim ),서성일 ( Seong Il Seo ),정창욱 ( Chang Wook Jeong ),변석수 ( Seok-soo Byun ),이지열 ( Ji Youl Lee ),홍준혁 ( Jun Hyuk Hong ),최인영 ( In Young Choi ) 한국보건정보통계학회(구 한국보건통계학회) 2018 보건정보통계학회지 Vol.43 No.3

목적: 전립샘암은 한국 남성에서 발병률이 급격히 증가하는 추세이다. 국소 전립샘암의 표준 치료로 근치적 전립샘 절제술이 시행되고 있으며 수술 기법은 개복, 복강경 그리고 로봇 수술로 나뉜다. 여러가지 수술 기법은 삶의 질, 경제적 측면, 수술 및 예후의 결과에서 차이가 있다. 이에 저자는 다기관 한국 전립샘 암 등록(KPCR) 데이터베이스를 이용하여 국소 전립샘 암 수술을 시행한 환자들의 결과와 예후에 대한 결과를 비교하고자 한다. 방법: KPCR 데이터베이스에는 5개 의료기관에서 수집한 6,032명의 데이터가 수집되어 있고 데이터의 무결성 보장을 위해 데이터 표준화 및 품질 관리를 시행하였다. KPCR 데이터베이스로부터 분석에 필요한 데이터를 추출하였다. 추출된 데이터는 2006년 1월부터 2011 년 12월까지 수집된 3,262명으로 최종 분석을 시행하였다. 이 데이터를 이용하여 수술 기법에 따른 국소 전립샘 암 환자의 인구학적 특성, 수술 결과 및 예후에 대해 분석하였다. 통계 분석방법은 one-way ANOVA, chi-square test, post-hoc 분석을 실시하였다. 무재발 생존율 분석을 위해 Kaplan-Meier와 multivariable Cox proportional hazard regression model을 통해 분석을 실시하였다. 결과: 분석 결과, 초기 전립샘 특이 항원치의 평균 값은 10.30 ng/mL이었다. 총 환자의 56.7%는 임상 병기 T2를, 43.3%는 병기 T1을 가지고 있었고 환자의 64.4%는 글리슨 스코어가 7 이상이었다. 절제면 양성률의 결과는 개복수술이 33.6%, 복강경 수술이 27.0%, 로봇수술이 28.8%로 나타났다(p <0.001). 로봇수술은 수술 후 합병증 및 예상 출혈량 결과에서 우수한 결과를 나타냈다. 5년 생화학 무 재발 생존율은 전체 환자에서 77.0%의 결과를 보였고 세 수술 기법은 임상 결과에 있어서 차이가 없었다. 또한 Cox 회귀분석 결과 세 수술기법은 생존율에 영향을 미치지 않았다. 결론: 본 연구결과는 국소 전립샘 암 환자의 예후와 특성을 설명한다. KPCR 데이터베이스를 통한 본 결과는 환자와 의료진의 올바른 의사 결정에 도움을 줄 것이라는 것을 보여준다. Objectives: Prostate cancer, commonly is rapidly increasing the incidence of prostate cancer among Korean men. Primary treatment of localized prostate cancer involves radical prostatectomy, and surgery techniques are divided into the abdominal, laparoscopic, and robotic surgery. Different surgical techniques differ in quality of life, economic aspect, and outcome of surgery and prognosis. Therefore we compared the outcomes and prognosis of patients who underwent surgery for localized prostate cancer using the multicenter Korean Prostate Cancer Registry (KPCR) database. Methods: The KPCR database collected data of 6,032 patients from five medical institutions, and data standardization and quality management were performed to ensure data integrity. We extracted data necessary for analysis from the KPCR database. We analyzed data for 3,262 patients during the period from January 2006 to December 2011. The demographic characteristics, surgical outcomes, and prognosis of patients with localized prostate cancer were analyzed. All statistical analyses were performed using one-way ANOVA, chi-square test, and post-hoc analysis. We used the Kaplan-Meier method and multivariable Cox proportional hazard regression model for biochemical recurrence-free survival rate (BCR-FS) analysis. Results: The analysis results showed that the average initial prostate specific antigen value was 10.30 ng/mL. A total of 56.7% of the patients had clinical stage T2, 43.3% had stage T1, and 64.4% of the patients had a Gleason score of more than 7. The rate of positive surgical margin was radical retropubic prostatectomy, laparoscopic radical prostatectomy, robotic-assisted laparoscopic radical prostatectomy (RALP) as 33.6%, 27% and 28.8%, respectively (p<0.001). The RALP gave excellent results for postoperative complication, and estimated blood loss (EBL). The 5-year overall BCR-FS was 77.0%, and the three surgical techniques did not differ in clinical outcomes. Cox regression analysis showed that the surgical technique did not affect the biochemical recurrence rate. Conclusions: Our study describes the characteristics of patients with localized prostate cancer and their prognosis. These results indicate that patients and medical staff can rely on information from the KPCR database for decision-making.

Preparation of a TiO₂ Film Using a TEOS Binder and Its Application to the Photodegradation of Benzene

Kim, Sung-Wook,Kang, Misook,Choung, Suk-Jin 한국공업화학회 2005 Journal of Industrial and Engineering Chemistry Vol.11 No.3

This study focuses on the photocatalytic decomposition of benzene on a TiO₂(Degussa P-25) thick film, at a high concentration, fixed on a Pyrex glass substrate using a TEOS (tetraethylorthosilicate) binder. Under UV radiation (365 ㎚) for 1 h, 100 p㎛ of benzene was completely decomposed in a photocatalytic batch system. The most effective photodecomposition of benzene was observed at a Ti/Si ratio (in a TEOS binder) of 0.67 in a TiO₂ film. In UV-Vis spectra, the absorption band of TiO₂ shifted to a shorter wavelength when a TEOS binder was used. The Si ion introduced from the TEOS binder proved to be better at increasing the photodegradation rate of benzene. Based on the relationship between the UV-Vis spectra and the benzene photodegradation, two models of the change of the TiO₂band gap are suggested. The first model presents electrons released from the valence band of TiO₂through UV radiation; these electrons become transferred into the valence band of SiO₂at lower energy states. The electrons are then readily transferred into the conduction band of TiO₂. The second model presents Sift formed from the TEOS binder exposed to UV light. Here, the electrons in the valence band of SiO₂are transferred to the conduction band of SiO₂, where upon they are readily moved to the conduction band of TiO₂.

과산화수소 보존표백시 Silicate 대체 약품에 관한 연구

김성권,정성욱,( Sung Kwon Kim,Sung Wook Choung,R . J . Michalowski ) 한국공업화학회 1998 공업화학 Vol.9 No.5