단일 입출력 비선형 시스템에 대한 확장된 직접학습제어

박중민,안현식,김도현,Park, Joong-Min,Ahn, Hyun-Sik,Kim, Do-Hyun 대한전자공학회 2002 電子工學會論文誌-SC (System and control) Vol.39 No.5

본 논문에서는 주어진 작업을 반복적으로 수행하는 시스템을 효과적으로 제어하기 위하여 확장된 형태의 직접학습제어방법을 제안한다. 직접학습제어는 기존의 반복학습제어에서, 원하는 출력에서의 작은 변화에 대해서도 학습과정을 처음부터 다시 수행해야 한다는 단점을 극복하기 위해 제안되었다. 이미 학습되어 있는 출력궤적과 특별한 비례(proportional)관계를 갖는 새로운 원하는 출력궤적이 주어졌을 때 직접학습제어를 이용하면 다시 반복학습과정을 수행할 필요없이 원하는 제어입력을 직접 구할 수 있다. 우선, 대부분의 기존의 직접학습제어방법은 단일 입출력 비선형 시스템의 상대차수가 1인 경우에만 적용 가능함을 보이고, 시스템의 상대차수에 대한 정보를 이용하여 상대차수가 1이상인 비선형 시스템에 적용할 수 있는 확장된 형태의 직접학습제어를 제안한다. 또한, 상대차수가 2이상인 임의의 비선형 시스템에 대하여 컴퓨터 모의실험을 수행하고 제안된 직접학습제어방법의 타당성 및 성능을 확인한다. In this paper, an extended type of a direct learning control(DLC) method is proposed for the effective control of systems which perform a given task repetitively. DLC methods have been suggested to overcome the defects of iterative learning control, the learning process should be resumed from the beginning even if a slight change occurs in the desired output pattern. If a given desired output trajectory is "proportional" to the output trajectories which are learned previously, we can obtain the desired control input directly without the iterative learning process by using the DLC. First, most existing DLC methods are shown to be applicable only to single-input single-output systems with the relative degree one and then, an extended type of DLC is proposed for a class of nonlinear systems having the relative degree more than or equal to one by using the known relative degree of a nonlinear system. By the simulation results for the arbitrary nonlinear system with the relative degree more than one, the validity and the performance of the proposed DLC method are examined.

외과 전공의에 의해 시행된 복강경 충수절제술의 안전성

박중민(Joong-Min Park),김진(Jin Kim),김정윤(Cheong-Yoon Kim),최동진(Dong-Jin Choi),김선한(Soen-Han Kim),김종석(Chong-Suk Kim),서성옥(Sung-Ock Suh),김영철(Young-Chul Kim) 대한외과학회 2008 Annals of Surgical Treatment and Research(ASRT) Vol.75 No.5

Purpose: Although laparoscopic surgery has many advantages and has become popular in various disease settings, surgical residents do not yet have sufficient opportunity to perform laparoscopic surgery. Appendectomies are the most common procedures performed by surgical residents, and they may be suitable for gaining them laparoscopic experience. We had our residents perform laparoscopic appendectomies and analyzed clinical outcomes to verify the utility of this procedure in providing laparoscopy education. Methods: Between September 2006 and December 2007, 384 patients with a preoperative diagnosis of acute appendicitis underwent laparoscopic appendectomy (n=191, LA) or open appendectomy (n=193, OA). Patient demographic data and outcomes for the two groups were compared. In the LA group, cases performed by surgical residents were compared against those performed by surgical specialists. Results: Both groups of patients were comparable demographically. The incidence of complicated appendicitis in the LA group was 19.4% and that in the OA group was 25.9% (P=0.126). Operative time was similar between the two groups. Postoperatively, recovery time was shorter in the LA group than in the OA group, especially for patients with non-complicated appendicitis. LA performed by surgical residents showed similar outcomes, including operative time and postoperative recovery parameters. Conclusion: Laparoscopic appendectomy appears to have many advantages, such as less pain, rapid postoperative recovery, and more economic differential diagnosis. This procedure can be performed safely by surgical residents. Thus, laparoscopic appendectomy is a suitable procedure for laparoscopic surgery education for surgical residents.

외과 전공의 자율평가

박중민(Joong-Min Park) 대한외과학회 2022 대한외과학회 학술대회 초록집 Vol.2022 No.11

Enhancement of activity and stability of xylanase in alkaline pH by directed evolution

Joong Min Park(박중민),Seong Pil Ko(고성필),Jung Hoe Kim(김정효) 한국생물공학회 2004 한국생물공학회 학술대회 Vol.2004 No.4

Improvement of activity and stability of xylanase used by directed evolution under alkaline conditions

Joong Min Park(박중민),Jung Hoe Kim(김정회) 한국생물공학회 2004 한국생물공학회 학술대회 Vol.2004 No.10

조기위암에서 복강경 위절제술의 합병증과 연관요소 분석

김민균(Min-Kyoon Kim),박중민(Joong-Min Park),지경천(Kyong-Choun Chi),김종석(Chong-Suk Kim) 대한외과학회 2010 Annals of Surgical Treatment and Research(ASRT) Vol.79 No.5

Purpose: Although laparoscopy-assisted gastrectomy (LAG) has become a popular treatment option for early gastric cancer, information about postoperative complications is limited in the literature and their risk factors vary among investigators. We analyzed the complications and their risk factors of LAG. Methods: We performed LAGs in 92 gastric cancer patients from July 2006 to December 2009. LAG indication was gastric cancer preoperatively diagnosed as cT1N0. Clinical and operative data and perioperative complications were retrospectively reviewed. According to the surgical experience, cases were divided into early (1∼40) and late (41∼92) groups because operative times stabilized after the 40th case. Results: There were no open conversion or mortality cases. Complications occurred in 11 patients. Two of them were non-surgical complications: postoperative delirium and cerebral infarction. Surgical complications were ischemic necrosis of transverse colon, duodenal stump leakage, anastomotic bleeding, leakage and stenosis. Univariate analysis proved that lymph node metastasis, and comorbidities were related to complication rate (P=0.000, P=0.032). Multivariate analysis proved that lymph node metastasis was the most important risk factor of complication (P=0.001). Surgical experience was not related to complication rate (12.5% in early period and 11.5% in late period, P=1.000). Conclusion: Complication rate of LAG was acceptable (11.9%). According to this study, unexpected lymph node metastasis is thought to be the most important risk factor for complications of LAG. Therefore, it is possible to accomplish lower complication rates in this procedure with careful patient selection through accurate preoperative evaluation.

재발된 위암 환자에서 발생한 악성 장폐쇄증의 수술적 치료

유병은,박중민,장유진,김종한,박성수,박성흠,김승주,목영재,김종석,Yoo, Byung-Eun,Park, Joong-Min,Jang, You-Jin,Kim, Jong-Han,Park, Sung-Soo,Park, Seong-Heum,Kim, Seong-Ju,Mok, Young-Jae,Kim, Chong-Suk 대한위암학회 2008 대한위암학회지 Vol.8 No.3

목적: 위암의 재발로 발생한 악성 장폐쇄증은 치료의 효과와 생존율을 향상시키기 위하여 적합하게 치료되어야 한다. 본 연구에서는 위암으로 수술 후 재발되어 악성 장폐쇄증이 발생한 경우 수술 방법에 따른 치료 효과와 생존율의 차이를 알아보았다. 대상 및 방법: 1998년 1월부터 2008년 3월까지 위암의 재발로 악성 장폐쇄증이 발생하여 수술적 치료를 받은 환자들의 의무 기록을 후향적으로 분석하였다. 수술 방법은 절제술, 장루술, 우회술로 나누었고 치료의 성공은 유동식 이상의 경구 섭취가 가능한 것으로 보았다. 결과: 42명의 환자에 대해 46회의 수술이 시행되었으며 절제술이 12회, 장루술이 24회, 위회술이 10회이었다. 입원기간과 유동식 이상의 경구 섭취까지의 기간은 장루술이 가장 짧았다. 수술 후 합병증은 10예(21.7%)에서 있었고 수술 후 30일 이내에 사망한 경우는 4예(8.7%)이었다. 수술 방법에 따른 생존율의 차이는 없었다. 결론: 위암의 재발로 발생한 악성 장폐쇄증의 수술적 치료로 장루술은 입원일과 경구 섭취까지의 기간이 다른 수술법에 비해 짧기 때문에 일부 환자들에서 좋은 선택이 될 수 있다. 수술 방법에 따른 생존율의 차이는 없었으며 이는 악성 장폐쇄증의 경우 근치적 수술이 어려운 경우가 대부분이기 때문으로 생각된다. Purpose: Malignant bowel obstruction caused by recurrent gastric cancer must be treated appropriately to improve the effects of treatment and to prolong survival. We reviewed the surgical treatments for malignant bowel obstruction caused by recurrent gastric cancer. Materials and Methods: The subjects were patients with malignant bowel obstruction caused by recurrent gastric cancer and these patients were treated by surgical procedures at our hospital from 1998 to 2008. The patients were treated by resection, ostomy or bypass. The success of treatment was decided when the patients were able to tolerate more than a liquid diet. Results: 42 patients were treated 46 times by surgical procedures. Resection was done12 times, ostomy was done 24 times and bypass was done 10 times. The hospital stay and the period to liquid diet after the operation were shorter in the ostomy group. The post operative morbidity rate was 21.7% and the post operative death rate was 8.7%. There was no significant difference in survival according to the type of surgery. Conclusion: Ostomy is good choice for selected patients because it has a shorter hospital stay and period to liquid diet. There was no significant difference in survival according to the type of surgery because curative resection is difficult to perform in patients with malignant bowel obstruction.

위암의 주위 장기 침윤으로 합병 절제를 실시한 환자의 병리학적 병기 및 예후

변건영,박중민,김호일,김종한,박성수,김승주,목영재,김종석,Byun, Gun-Young,Park, Joong-Min,Kim, He-Il,Kim, Jong-Han,Park, Sung-Soo,Kim, Seong-Ju,Mok, Young-Jae,Kim, Chong-Suk 대한위암학회 2007 대한위암학회지 Vol.7 No.3

목적: 주위 장기를 침범한 위암의 수술적 치료는 주위 장기의 합병 절제를 포함한 광범위 확대 위절제술을 하거나, 또는 위공장문합술이나 위절제술을 통한 고식적 수술을 시행하게 된다. 그러나 고식적 수술을 할 경우 정확한 T, N 병기를 알 수 없기 때문에 환자의 예후를 예측하는 것이 적절하지 않다. 본 연구에서는 주위 장기 침윤으로 합병절제를 시행하여 최종적인 TNM 병기 결정이 이루어진 환자들의 예후를 분석하였다. 대상 및 방법: 1983년부터 2002년까지 고려대학교 의과대학 외과학교실에서 위암으로 수술 받은 환자 2,452명 중 수술 중 주위 장기의 직접 침윤이 발견되어 합병 절제를 시행한 102명의 환자를 분석하였다. 결과: 단변량 분석에서 암의 위치, 조직학적 분화도, 위벽 침윤도, 림프절 전이 정도, 원격전이 여부, 병리학적 병기, 근치절제 여부 및 침범한 장기의 개수에 따라 생존율의 차이가 있었으며, 환자의 나이, 성별, 위 절제범위, Borrmann 분류, 암의 크기, 림프절 곽청 범위와 절제 림프절의 개수, 합병 절제한 장기의 종류 및 개수 등은 생존율의 차이를 나타내지 않았다. 다변량 분석에서는 암의 위치, 근치절제 여부, 림프절 전이 정도가 독립적인 예후인자였다. 결론: 위암의 주위 장기로의 직접 침윤이 의심되더라도 실제 T4인 경우는 64.7%이었다. 따라서 주위 장기의 침윤이 의심되더라도 적극적인 절제술로 가능하면 근치 절제술을 하도록 노력하는 것이 정확한 병기 결정을 통한 예후 예측과 생존율의 향상을 위해서 필요하다. Purpose: The surgical treatment of gastric cancer that invades adjacent organs is a radical gastrectomy with combined resection including the adjacent organs or a palliative operation by performing either a gastrojejunostomy or gastrectomy. However, since it is impossible to determine the exact stage of the cancer, either T or N, in the case of palliative surgery, it is inappropriate to predict patient prognosis. This study analyzes the prognoses for patients whose final TNM stages are determined by a combined resection performed due to macroscopical infiltration into the adjacent organs. Materials and Methods: Of 2,452 patients that underwent surgery for gastric cancer at our hospital from 1983 to 2002, we evaluated 102 patients where a combined resection was performed because direct infiltration into the adjacent organs was discovered. Results: Univariate analysis showed that the survival rate differed by the depth of invasion into the gastric walls, the degree of lymph node metastasis, distant metastasis, pathological TNM stage, surgical curability, the location of tumor, and histological differentiation. By multivariate analysis, it was found that the surgical curability, the location of the tumor and the degree of lymph node metastasis were independent prognostic factors. Conclusion: It is suggested that even when infiltration into adjacent organs is suspected, radical surgery should be performed as to allow a prediction of prognosis through an exact determination of disease stage, and to improve the survival rate.

위선암종에서 핵의 Retinoic Acid Receptor (RAR) 및 cAMP Response Element Binding Protein (CREB)의 면역조직화학적 발현양상

한호선,김용석,박중민,최유신,차성재,김미경,지경천,Han, Ho-Sun,Kim, Yong-Seok,Park, Joong-Min,Choi, Yoo-Shin,Cha, Seong-Jae,Kim, Mi-Kyung,Chi, Kyung-Choun 대한위암학회 2008 대한위암학회지 Vol.8 No.4

목적: 인체 내 여러 조직에서 상피세포의 분화 및 증식에 중요한 역할을 담당한다고 알려진 retinoic acid (RA)와 여러 유전자들에서 전사조절인자로 성장관여 유전자들의 활성화에 관여하며 세포증식 및 분화에 매우 중요한 세포내 조절인자인 CREB의 발현정도와 위선암종간의 상호 연관성 및 병리학적 인자들과의 관계를 관찰하였다. 대상 및 방법: 중앙대학교 의과대학 용산병원에서 1998년 1월부터 2007년 12월까지 위절제술을 시행 받고 위선암종으로 진단받은 환자의 위조직표본 중 보존상태가 양호한 파라핀 포매괴 150예를 연구대상으로 조직 표본에서 면역 조직화학적 염색을 통해 관찰하였다. 결과: 1. RAR의 발현은 장형 위선암종(72.2%)에서 미만형 위선암종(40.5%)보다 높게 나타났으며(P<0.01), 림프절 전이가 있는 경우(74.7%)가 림프절 전이가 없는 경우(49.2%)보다 의미 있는 발현양상을 나타냈다(P<0.01). 2. cAMP response element binding protein (CREB)의 발현은 장형 위선암종(69.4%)에서 미만형 위선암종(38.1%)보다 높게 나타났으며(P<0.01), 림프절 전이가 있는 경우(71.1%)가 림프절 전이가 없는 경우(47.8%)보다 높은 발현양상을 나타냈다(P<0.01). 3. 총 150예의 위선암종에서 RAR은 63.3% (95/150), CREB은 60.7%(91/150)에서 발현을 나타냈다(P<0.01). 결론: 이상의 결과로 RAR과 CREB은 조직학적 분화도 및 종양의 전이와 관련이 있고, 이들의 발현이 장형 위선암종에서의 생물학적 악성도에 관한 예후인자로서 관련이 있으나 이들의 발현이 위선암종에 미치는 생물학적 기전에 대한 추가 연구가 필요하다. Purpose: Transcriptional factors of CREB (cAMP response element binding protein) are involved in regulating the gene expression in response to a variety of signaling pathways. The proteins produced by the CREB genes play key roles in many physiological processes, including memory and long-term potentiation. The retinoic acid receptor (RAR) axis mediates epithelial cell differentiation and proliferation in many tissues. This study examined the expressions of RAR and CREB and their relationship with the clinicopathologic factors and their significance. Materials and Methods: The levels of the RAR and CREB expressions were measured in 150 gastric adenocarcinomas by performing immunohistochemical staining. Results: 1. An RAR protein expression was found in 63.3% of the adenocarcinomas (95/150) and a CREB expression was found in 60.7% (91/150) of the adenocarcinomas. 2. An RAR protein expression was found in 72.2% (78/108) of the intestinal type adenocarcinomas and in 40.5% (17/42) of the diffuse type adenocarcinomas (P<0.05). Based on the depth of invasion, an RAR protein expression was found in 58.3% (14/24) of the T1 adenocarcinomas, in 61.9% (13/21) of the T2 adenocarcinomas, in 63.5% (61/96) of the T3 adenocarcinomas, in 77.8% (7/9) of the T4 adenocarcinomas and in 74.7% (62/83) of the adenocarcinomas with lymph node metastasis and in 49.2% (33/67) of the adenocarcinomas without lymph node metastasis (P<0.01). 3. A CREB expression was found in 69.4% (75/108) of the intestinal type and in 38.1% (16/42) of the diffuse type (P>0.05). Based on the depth of invasion, a CREB expression was found in 50% (12/24) of the T1 adenocarcinomas, in 52.4% (11/21) of the T2 adenocarcinomas, in 64.6% (62/96) of the T3 adenocarcinomas, in 66.6% (6/9) of the T4 adenocarcinomas, in 71.1% (59/83) of the adenocarcinomas with lymph node metastasis and in 47.8% (32/67) of the adenocarcinomas without lymph node metastasis (P<0.01). 4. The RAR protein and CREB expressions coincided in 71.4% of the gastric adenocarcinomas and a significant correlation between them was found (P<0.05). Conclusion: We found a significant relationship between the expression of RAR and CREB and the histology and lymph node metastasis of gastric cancer. Further studies are needed to confirm their biologic meaning in gastric carcinogenesis.

복강경 충수절제술로 치료한 급성 충수염의 항생제 감수성 및 세균학적 고찰

이재원(Jae-Won Lee),박중민(Joong-Min Park),이승은(Seung-Eun Lee),박용검(Yong-Geum Park),지경천(Kyong-Choun Chi) 대한외과학회 2010 Annals of Surgical Treatment and Research(ASRT) Vol.79 No.5

Purpose: This study was designed to evaluate the bacteriological characteristics and antibiotics sensitivity in acute appendicitis. Methods: The microbiologic culture and antibiotics sensitivity tests were done on 165 patients who underwent laparoscopic appendectomy under the diagnosis of acute appendicitis. The postoperative complications were also checked. The microbiologic and clinical results were compared between perforated and non-perforated groups. Results: The most common organism cultured from the periappendiceal fluid was Escherichia coli (51.2%), followed by Enterobacter (16.2%) and Pseudomonas (8.9%). In the antibiotics sensitivity test, ciprofloxacin and levofloxacin were highly susceptible. Ceftriaxone and cefotaxime were also highly susceptible. Piperacillin/tazobactam, imipenem and meropenem were very highly susceptible. The complication rate of perforated appendicitis group (17.9%) was higher than that of the non-perforated appendicitis group (7.1%) (P<0.001). A surgical drain was used more frequently in perforated group (23% vs 84.6%, P<0.001). The mean in-patient days were longer in the perforated group (5.7 vs 7.2 days, P<0.001). In the patients with infectious wound complication, antibiotic resistance was more prominent in the non-perforated group than in the perforated group. Conclusion: In the perforated appendicitis group, more precise and careful procedure was required. In the non-perforated appendicitis group, more prudent use of the available antibiotics to conserve valuable therapeutic resources and improved infection control to limit the spread of resistant organisms was required.