• Journal of Microbiology and Biotechnology
• /
• 제16권12호
• /
• pp.1890-1896
• /
• 2006

Lumostatic operation for cultivation of Haematococcus pluvialis was assessed to test the scale-up strategy of photobioreactors. Lumostatic operation is a method of maintaining a proper light condition based on the specific light uptake rate ($q_e$), by cells. Lumostatic operations were performed in 0.4-, 2-, 10-, and 30-1 scale bubble column photobioreactors and the results were compared with cultures illuminated with constant light intensity. Significant differences were observed in the maximal cell concentrations obtained from 0.4-, 2-, 10-, and 30-1 scale photobioreactors under constant light intensity, yielding the maximal cell concentrations of $2.8{\times}10^5$, $2.2\times10^5$, $1.5\times10^5$, and $1.1\times10^5$ cells/ml, respectively. The maximal cell concentration in a 0.4-1 photobioreactor under lumostatic operation was $4.3\times10^5$ cells/ml. Furthermore, those in 2-, 10-, and 30-1 scale photobioreactors were about the same as that in the 0.4-1 photobioreactor. The results suggest that lumostatic operation with proper $q_e$ is a good strategy for increasing the cell growth of Haematococcus pluvialis compared with a constant supply of light energy. Therefore, lumostatic operation is not only an efficient way to achieve high cell density cultures with minimal power consumption in microalgal cultures but it is also a perfect parameter for the scale-up of photobioreactors.

• 한국컴퓨터정보학회:학술대회논문집
• /
• 한국컴퓨터정보학회 2011년도 제43차 동계학술발표논문집 19권1호
• /
• pp.107-108
• /
• 2011

철도기술의 발전 이후 현재 도시철도에서는 국내 처음으로 열차의 안전한 운행 제어를 위한 자동/무인 운전이 가능한 자동 열차 운행 장치(ATO)를 도입해 안정적으로 정시 운행을 하고 있다. ATO 자동운전은 제어기준 값(목표속도)과 피드백 값(실제속도)간의 오차에 의한 전동차의 역행과 제동을 반복함으로 에너지 효율 낮다. 본 논문에서는 고정된 역간 거리를 정해진 운전 시분 내에 주행에너지를 최소화하며 주행하는 열차의 특성을 파악하고 모델링한다. 따라서 5호선 실 노선 구간별 운전시분 내에서 실측 데이터 분석을 위해 직선구간/구배구간/곡선구간 등 구간을 선정하고 그 구간에서 열차의 주행패턴에 따라 변화하는 주행에너지를 최소화하는 최적의 주행 패턴을 제시하였다.

• 한국안전학회지
• /
• 제35권1호
• /
• pp.107-115
• /
• 2020

This paper introduces the first vital area identification (VAI) process for the physical protection of nuclear power plants (NPPs) during low power and shutdown (LPSD) operation. This LPSD VAI is based on the 3rd generation VAI method which very efficiently utilizes probabilistic safety assessment (PSA) event trees (ETs). This LPSD VAI process was implemented to the virtual NPP during LPSD operation in this study. Korea Atomic Energy Research Institute (KAERI) had developed the 2nd generation full power VAI method that utilizes whole internal and external (fire and flooding) PSA results of NPPs during full power operation. In order to minimize the huge burden of the 2nd generation full power VAI method, the 3rd generation full power VAI method was developed, which utilizes ETs and minimal PSA fault trees instead of using the whole PSA fault tree. In the 3rd generation full power VAI method, (1) PSA ETs are analyzed, (2) minimal mitigation systems for avoiding core damage are selected from ETs by calculating system-level target sets and prevention sets, (3) relatively small sabotage fault tree that has the systems in the shortest system-level prevention set is composed, (4) room-level target sets and prevention sets are calculated from this small sabotage fault tree, and (5) the rooms in the shortest prevention set are defined as vital areas that should be protected. Currently, the 3rd generation full power VAI method is being employed for the VAI of Korean NPPs. This study is the first development and application of the 3rd generation VAI method to the LPSD VAI of NPP. For the LPSD VAI, (1) many LPSD ETs are classified into a few representative LPSD ETs based on the functional similarity of accident scenarios, (2) a few representative LPSD ETs are simplified with some VAI rules, and then (3) the 3rd generation VAI is performed as mentioned in the previous paragraph. It is well known that the shortest room-level prevention sets that are calculated by the 2nd and 3rd generation VAI methods are identical.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제27권4호
• /
• pp.349-352
• /
• 2001

Dental laser provides many advantages to the clinicians. Those are excellent hemostatic effect, good operating sight, minimal adjacent tissue injury, reduction of postoperative swelling & pain, reduction of postoperative infection, reduction of scar tissue & contraction, etc. The purpose of this study is to observe how these advantages work after surgical extraction of impacted third molar. From march 2000 to july 2000, we have randomly divided the patients who had been surgically extracted unilateral impacted third molar into two groups. The first group comprised $CO_2$ laser illumination with 3 watts, defocusing & continuous mode, rotating motion for about 3 minutes after finishing of surgical extraction & suture. The other group patients were not irradiated. The medications in two groups were same. We measured pain, swelling and trismus three times(pre-operation, first day after operation, and 7th day after operation). The number of the patients who had measured three times all are 64, laser irradiated groups are 36 and non-irradiated groups are 28. The age ranged from 19 to 50, with a mean of 27.9 years. The operative time ranged from 3 minutes to 50 minutes, with a mean of 12.1 minutes. In the $CO_2$ laser group, the pain intensity of the 7th day after operation was still increased significantly comparing with that of the pre-operation and the distance which were measured for the swelling was different significantly. In the other group, the mouth opening limitation was still decreased significantly.

• Advances in pediatric surgery
• /
• 제11권2호
• /
• pp.131-140
• /
• 2005

The purpose of this study is to review the operative management and outcome of operation for Crohn's disease. The medical records of 17 patients who underwent operations for Crohn's disease at Seoul National University Children's Hospital from January of 1988 to June of 2005 were reviewed. The male-to -female ratio was 1.8: 1. The median age at the onset of symptoms and the time of diagnosis was 9 years 6 months and 11 years 6 months respectively. The median time interval from diagnosis to operation was 2 years and 1 month (0 month~8 years). The ileocolic or ileocecal region was the most common site of involvement. The indications for operation were intractable symptoms (8 cases) and obstruction or stricture (7 cases). The median postoperative hospitalized days were 14.4 days (8~35 days). Five patients (29 %) experienced postoperative complications. Symptom free state or symptom relief was observed in 11 cases after surgery and 6 cases had intermittent episodes of remissions and recurrences. In pediatric Crohn's disease patients who present with intractable symptoms despite medical treatment or develop surgical complications, symptom free state or symptom relief can be achieved by minimal resection of the diseased segment.

• Clinics in Shoulder and Elbow
• /
• 제4권1호
• /
• pp.17-23
• /
• 2001

1990년부터 2000년까지 본원에서 modified Phemister 방법과 cerclage wiring 방법으로 치료하고 1년이상 추시가 가능했던 견봉쇄골관절탈구 환자 24례를 임상적으로 분석하여 다음과 같은 결과를 얻었다. 1. modified Phemister 방법을 시행한 10례에서 우수 8례(80%), 양호 1례(10%), 보통 1례(10%)이었다. 2. Cerclage wiring 방법을 시행한 14례에서 우수 11례(78%), 양호 1례(14%), 보통 1례(14)이었다. 3. 술후 합병증으로 modified Phemister 방법에서 2례에서 고정강선의 파열 및 이동이 있었으며, cerclage wiring 방법에서 2례에서 아탈구, 2례에서 강선의 파열은 있었으나 이동은 없었다. 4. 이상과 같은 결과로 보아 modified Phemister 방법과 cerclage wiring 방법의 비교시 방사선상 오구돌기와 쇄골간 이완의 정도의 차이와 기능상의 차이는 없었으나 견봉쇄골관절을 고정하지 않음으로서 쇄골의 회전운동을 제한하지않고, 외상성관절염을 피할 수 있고, 강선의 파열시 이동이 없어 제거가 쉬워서 cerclage wiring을 선호하였다.

• Advances in pediatric surgery
• /
• 제10권1호
• /
• pp.1-8
• /
• 2004

A re-pull-through operation for Hirschsprung's disease is performed when the primary operation has failed because of the remnant or acquired aganglionosis, anastomotic stricture and/or fistula. The purpose of this study is to review our experience of the re-pull-through procedure for Hirschsprung's disease. From May 1978 to July 2003, 26 patients who underwent re-pull-through operations at the Department of Pediatric Surgery, Seoul National University Children's Hospital, were studied retrospectively by means of chart review as well as telephone interview. The mean age at primary operation and re-operation were llmonths (2 months - 10 years) and 43 months (1 year - 23 years 3 months), respectively. Initial operation for Hirschsprung's disease was Duhamel's procedure in 17, Swenson's in 6 and Soave's 3. Causes of failure of primary operation were remains of secondary aganglionic segment (n=23), vascular arcade injury (n= 1), rectoperineal fistula (n=2, due to mesenteric torsion and poor blood supply), Mean interval between the primary operation and the re-operation was 34 months (6 months-22 years). Reoperation methods were Soave's in 12, Duhamel's in 8, APSP (abdomino-posterosagittal pull-through procedure) in 5, and Swenson's in 1 case. In 2 cases of repeated rectoperineal fistula or rectourethral fistula, re-APSP were performed 3 times, respectively. A total of 29 re-pull-through operations were performed. Postoperative complications were wound infection (n=1), adhesive ileus (n=1), rectoperineal fistula (n=3), rectourethral fistula (n=2), and death due to pulmonary embolism (n=1). Mean follow up period of reoperation was 78 months (1 month-23years). In current state, 2 patients have an ileostomy because of repeated rectoperineal fistula and rectourethral fistula. Of the remaining 23 patients, 21(91 %) are totally continent with or without minimal soiling. Reoperation for Hirschsprung's disease was effective and safe for the patients complicated to the initial pull-through operation.

• 대한두개안면성형외과학회지
• /
• 제9권2호
• /
• pp.101-104
• /
• 2008

Purpose: Diplopia and cosmetically unacceptable enophthalmos are the major complications of blow out fracture. Prolapse of orbital tissue into the sinuses, enlarged orbital volume, atrophy of orbital fat and loss of support of orbital walls play a role in the pathogenesis of enophthalmos. To correct post-traumatic enophthalmos, freeing of incarcerated orbital contents combined with reduction of bony orbital volume and reconstruction of suspensory support of globe is necessary. But remained enophthalmos after surgical treatment is difficult to correct completely. In this case, the authors performed implant insertion for affected orbit and endoscopic orbital decompression for unaffected orbit for correction of late enophthalmos. Method: We reviewed a girl patient with right inferomedial orbital wall blow out fracture, right zygoma fracture treated at our hospital for correction of enophthalmos. An 18-year-old female had sustained posttraumatic enopthalmos. Two surgical management was performed for correction blow out fracture at the other hospital. But residual diplopia, enophthalmos, cheek drooping were found. And then she transferred to our hospital. She had severe enophthalmos(5 mm) also had diplopia and extraocular muscle limitation. We performed operation for correction of enophthalmos. After operation, she showed minimal improvement of diplopia and enophthalmos(3 mm). The authors make plan for operation for correction enophthalmos due to cosmetical improvement. Implant insertion was performed for affected orbit. For unaffected orbit, nasoendoscopic medial orbital wall decompression was proceeded. Result: Correction of enophthalmos was found after operation and was maintained for nine years follow-up. Patient expressed satisfaction for the result. Conclusion: To correct persistant enophthalmos, we could have satisfactory result with orbital wall reconstruction on affected eye and decompression on unaffected eye.

• 한국정보통신학회논문지
• /
• 제17권4호
• /
• pp.945-952
• /
• 2013

QRS 영역 중 R파는 ECG 신호 중 가장 큰 대표 신호라 할 수 있으며, 이 점을 기준으로 다양한 특징점을 검출하기 때문에 R파의 검출성능을 높이기 위해 많은 노력을 기울여 왔다. 하지만 R파 검출은 여러 종류의 잡음성분들로 인하여 이를 분석하는데 어려움을 준다. 또한 QRS 영역의 진폭과 유사한 T파나 P파를 R파로 오인함으로써 검출의 어려움이 발생한다. ECG 신호처리는 하드웨어 및 소프트웨어 자원에 대한 효율성을 고려해야 하며, 소형화 및 저 전력을 위해 단순해야 한다. 즉, 최소한의 연산량으로 정확한 R파를 검출함으로써 다양한 부정맥을 분류할 수 있는 적합한 알고리즘의 설계가 필요하다. 따라서 본 연구에서는 차감 동작 기법(Subtractive Operation Method, 이하 SOM) 기반의 심전도 신호의 R파 검출 방법을 제안한다. 이를 위해 형태 연산을 통한 전처리 과정과 경험적 문턱값과 차감신호를 통해 R파를 검출하였으며, 검출의 효율성을 위하여 RR 간격을 이용한 동적 역탐색 기법을 적용하였다. 제안한 알고리즘의 R파 검출 성능을 평가하기 위해서 MIT-BIH 부정맥 데이터베이스를 사용하였다. 성능평가 결과, R파는 평균 99.41%의 검출결과가 나타났다.

• 대한교통학회지
• /
• 제25권5호
• /
• pp.195-207
• /
• 2007

수도권 광역통행의 과다한 승용차 이용은 서울시 교통문제의 핵이다. 시계 도로망의 혼잡과 더불어 도시내부로 유입된 승용차가 유발하는 2차 통행도 심각하므로 광역 승용차 통행을 줄이는 것이 시급하다. 이러한 문제를 해결하는 가장 효과적인 방안중 하나는 광역철도의 경쟁력 제고이다. 광역철도와 승용차를 비교해보면 대부분 수도권 지역에서 철도의 통행시간이 승용차를 초과하는 실정이다. 본 연구는 광역철도가 통행시간에 대한 경쟁력을 갖게 하기 위한 방안으로 대피선 설치를 통한 급행열차 도입을 제안한다. 급행과 완행열차의 혼합운행은 매우 정교한 기술적 검토를 요구하며 실질적인 운행방안의 제시가 필요하다. 본 연구에서는 급행열차에 대한 운전선도를 시뮬레이션하고 급완행 열차의 교행 패턴을 도출하는 스케쥴 작성 알고리즘을 제시하고 안산선을 대상으로 가상 적용 사례를 제시한다. 시뮬레이션 결과, 안산선의 경우 $1{\sim}2$개의 신규 대피선 설치를 통해 급행열차의 표정속도를 63kph 까지 향상시킬 수 있음을 입증한다.