SCG(Secure Communication Group)을 이용한 계층적 VPN(Virtual Private Network) 구성 및 특성

박찬우,한치문,Park, Chan-Woo,Han, Chi-Moon 대한전자공학회 2001 電子工學會論文誌-TC (Telecommunications) Vol.38 No.11

인터넷을 이용한 대부분의 VPN(Virtual Private Network)은 기업 데이터만을 보호하는 형태로 구성되어 있다. 그러므로 다양한 형태의 VPN 구성이 필요하다. 최근에 SCG(Secure Communication Group) 개념을 이용하여 VPN을 구성하는 방법이 연구되고 있다. 본 논문에서는 SCG 구성 방법인 Path-definition 방식과 Arca-definition 방식의 문제점을 분석하고, 인트라넷 VPN 환경에서 SCG 개념을 사용한 VPN 중 적용 가능한 여러 형태의 VPN 모델을 검토한다. 그리고 인터넷에 Area-definition 방식을 적용하고 SCG number를 이용한 계층적 VPN 구성 방법을 제안한다. 제안한 방식의 특성을 각 entity가 관리해야 할 키수 및 인증 회수에 대해 정량적으로 분석하고, 본 방식이 유효함을 나타낸다. Currently most of VPNs within internet has only capability to protect cooperate data. Recently, various types of VPNs are being studied based on the concept of SCG(Secure Communication Group). This paper analyses the problems of path-definition method and area-definition method of VPNs using SCG technology, and discusses the possible models among VPNs using SCG technology. This paper proposes the hierarchal VPN configuration method using SCG number and internet based area definition method, and analyze the characteristics of the proposed VPN model on the point of the authentication frequency and the number of managements keys.

난류 발생기의 형상에 따른 수직 PCB채널에서의 열전달 및 압력손실 변화

박찬우,장승일,정종수,남평우,Park, Chan-U,Jang, Seung-Il,Jeong, Jong-Su,Nam, Pyeong-U 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.7

This study was performed to analyze the cooling effect of heated ribs which are frequently used for cooling of electronic parts, using the numerical method. To prevent the excessive pressure drop due to turbulence promoters for the enhancement of heat transfer rate especially, the effect of the angle of turbulence promoter was investigated by the numerical analysis. Heat transfer rate with turbulence promoters with rectangular cross-section increased by 13% in average, but the coefficient of pressure drop increased by 1.68 times than that without them. In the present study, triangular cross-sectional shape turbulence promoters were suggested and numerically tested. Pressure drop of turbulence promoter with the 30 degree triangular cross-sectional shape decreased by 30% from that of rectangular cross-section promoters while heat transfer rate was almost the same. While with 4 turbulence promoters, the heat transfer rate increased by 21%, the pressure drop increased 4 times. It means that the higher capacity of cooling fan should be needed. With the triangular cross-sectional shape, the size of vortex region at the rear of promoters became considerably smaller, so pressure drop became smaller. The effect of the change of cross-sectional shape was not found in the flow pattern near the ribs, so that heat transfer characteristics in the ribs were not changed.

온실가스 배출규제와 기업전략

박찬우,Park, Chan-U 환경보전협회 2008 환경정보 Vol.30 No.375

주요 사찰에 일제가 심은 전나무 노거수의 식재의미 연구

박찬우,정미애,이연희,Park, Chan-Woo,Jeong, Mi-Ae,Lee, Yeon-Hee 한국조경학회 2015 韓國造景學會誌 Vol.43 No.4

본 고는 주요 사찰에 노거수로 현존하는 대부분의 전나무는 일제에 의해 구한말부터 일제강점기 동안 신목(神木)으로 심어졌다는 가설을 증명하기 위해 연구되었다. 전나무 노거수의 현존량과 식재위치 특성, 전나무 노거수의 식재시기 특성, 일본의 고대신앙과 전나무의 연관성을 분석하였다. 전나무 노거수를 신목이라고 판단하는 이유는 다음 세 가지이다. 첫째, 일본 신사에서는 가도로부터 뻗은 참배로에 가장 많은 신목이 심겨지는데, 우리 사찰에서는 일본의 참배로와 비슷한 공간인 일주문에서 누문 사이에 가장 많이 심겨진 식재위치의 공통점 때문이다. 둘째, 몇 개의 주요 사찰에서 가슴높이 직경이 가장 큰 전나무를 조사한 결과, 100cm에서 60cm 사이의 범주여서 일본 불교의 조선 개교 원년인 1877년부터 일제강점기 1945년 사이, 2015년 현재 70년생에서 138년생 사이에 포함되는 크기로 판단되기 때문이다. 셋째, 1877년 일본 불교계가 조선개교를 시작하면서 일본 고대사에 있는 신공황후의 삼한출병을 보살펴준 스와대사의 신(神)을 일제의 수호신으로 삼고, 우리나라 주요 사찰에 현신시키기 위하여 전나무를 심었을 것이라고 하는 연관성이 너무도 자연스럽기 때문이다. 우리 사찰의 전나무 노거수는 강제적이었든지 부지불식간에 식재되었든지 그 식재의미에 대한 적절한 평가가 이루어지지 않은 채 현재의 거목으로 성장하였다. 본고의 주장에 대한 철저한 검증과 본 이슈에 대한 논의를 기대한다. This study investigates how Abies holophylla was planted as a tree sacred to the gods by Japan during the late Chosun and Japanese colonial periods. This study surveyed the current conditions of old Abies holophylla geological information, year planted, and the relationship between Abies holophylla and traditional Japanese values. The reasons that Abies holophylla was considered a tree sacred to the gods are as follows. Firstly, trees are planted on the spaces between Iljumun and Numun in Buddhist temples of Korea in the same way as trees are planted on the roads for worship in traditional temples of Japan. Secondly, tree diameter at breast height ranged from 60cm to 100cm. This means that the Abies holophylla trees range in age from 70 years to 138 years, showing that the trees were planted at the period between the beginning of Japanese Buddhism(1877) and the Japanese Colonial Period (1945). Thirdly, conclusions regarding why the Abies holophylla were planted in Korean temples at the beginning of Japanese Buddhism will be drawn based on the records that Jingu-Kogo's Conquest of Silla was taken care of the Suwataisha as a tree sacred to the gods in Japanese tradition. The reason for which Abies holophylla was planted in Korean temples should be evaluated through the remnants of Japan in the past. The issue of the old Abies holophylla in Korean temples should be investigated and further discussed in depth.

엣칭용 염화철폐액의 처리에서 미반응철의 재생방법

박찬우,정우원,이만호 ( Chan Woo Park,Woo Won Jeung,Man Ho Lee ) 한국공업화학회 1997 공업화학 Vol.8 No.4

철 환원법에 의한 엣칭용 염화철 폐액의 처리에서 니켈이 부착된 미반응 철분을 재생하기 위해서 볼밀 및 초음파 처리를 사용하였다. 철분을 2회 재생하였을 때 니켈 제거 효율은 볼밀을 2시간 처리한 경우와 초음파를 4시간 처리한 경우 각각 94.0%와 82.1%이었다. 재생 처리하지 않고 철분을 3회 사용하였을 때 니켈 제거 효율은 40.0%이었다. 처리시간이 증가함에 따라 볼밀처리에서는 철분의 크기가 감소하였으나, 초음파 처리에서는 철분의 크기 변화가 거의 없었다. The regeneration of the iron powders in the treatment of FeCl₃ etching solution containing nickel by ball-mill and ultrasonic treatments has been studied. When the unreacted iron powders were treated twice, the removal efficiency of nickel was 94.0% for the ball-mill treatment and 82.1% for the ultrasonic treatment. But the removal efficiency of nickel was 40.0% for the untreated iron powders. As the treatment time was increased, the particle size of iron powders was decreased for ball-mill treatment and almost not changed for ultrasonic treatment.

난관 불임환자에서 난관 개통술시 진단복강경의 효용성

박찬우,김혜옥,허걸,양광문,김진영,송인옥,유근재,전종영,이경상,강인수,궁미경,Park, Chan-Woo,Kim, Hye-Ok,Hur, Kuol,Yang, Kwang-Moon,Kim, Jin-Young,Song, In-Ok,Yoo, Keun-Jae,Jun, Jong-Young,Lee, Kyung-Sang,Kang, Inn-Soo,Koong, Mi-Kyoung 대한생식의학회 2003 Clinical and Experimental Reproductive Medicine Vol.30 No.2

Objective: To evaluate whether diagnostic laparoscopy before transcervical fallopian tube catheterization (TFTC) would improve tubal recanalization rate and pregnancy rate in patients with bilateral proximal tubal blockage in hysterosalpingogram (HSG). Methods: The retrospective study was performed in those underwent TFTC from January 1998 to December 2001. A total of 50 patients with bilateral proximal tubal blockage in HSG were subjected to TFTC sequentially using repeated HSG (rHSG), selective salpingography (SS) followed by tubal catheterization (TFTC). Each procedure was terminated once patency had been achieved without proceding to the next technique. In Group A patients (n=35, 64 tubes), diagnostic laparoscopy was performed before TFTC was taken to exclude the tube combined with peritubal adhesion or distal tubal pathology. In Group B, patients (n=15, 26 tubes) were performed TFTC without diagnostic laparoscopy. Results: There were significant difference in clinical pregnancy rate (45.7% vs 15.4%, p=0.034) but no differences were found in recanalization rate (75.0% vs 73.1%) and complication rate (8.6% vs 13.3%). Although there is no signficant difference, more tubes were canalized by SS, which means tubal obstruction rather than occlusion, in Group A (25.0% vs 5.3%, p=0.069). Conclusion: Diagnostic laparoscopy would be effective in the selection of tube for the relatively inexpensive and less invasive TFTC or patients in need of assisted reproductive technologies. With the tubes without combined peritubal adhesion or distal tubal pathology, pregnancy rate was significantly increased.

Oncological and Aesthetic Outcomes of Nipple-Areolar Complex(NAC) Sparing Mastectomy and Immediate Breast Reconstruction

박찬우,안희창,김연환,정민성,Park, Chan Woo,Ahn, Hee Chang,Kim, Youn Hwan,Jung, Min Sung The Korean Society for Microsurgery 2012 Archives of reconstructive microsurgery Vol.21 No.2

Background: Women receiving mastectomy usually prefer a single-stage surgical procedure without the need for additional surgery. Hence, nipple sparing mastectomy was introduced, and the follow-up data on the aesthetic outcome and recurrence of breast cancer were investigated in this study. Materials and Methods: The study subjects comprised 22 patients who received nipple-sparing mastectomy and immediate breast reconstruction using the free transverse abdominal rectus abdominis myocutaneous flap between June of 2007 and June of 2012. The patients' aesthetic outcomes were measured with 2 methods for the objective result: Breast size measurements and breast volume calculation both at preoperative phase and postoperative 1 years phase. Also, the patients' satisfaction was evaluated at postoperative 1 year with the self-assessment questionnaire. Follow up check for assessing cancer recurrence was performed for an average period of postoperative 1063 days. Results: First, in objective aesthetic outcome, there were no significant differences between the preoperative and postoperative results on both the breast size and the volume. Second, the patient satisfaction analysis scores were graded as very good in 15 patients (68.2%), and as good in 6 patient (27.3%). Most of the patients were very satisfied with our surgery method. Last, there was no local or distant recurrence in these 22 patients during the follow-up period. Conclusion: In this study, the nipple-sparing mastectomy achieved satisfactory results for the breast scar and shape with a single-stage surgical procedure, and the cancer recurrence rate was not significantly different from that of the conventional mastectomy. Besides, the nipple-sparing mastectomy is more cost-effective than the conventional mastectomy since it reduces the need for additional procedures. However, we think that it is necessary to determine the long-term outcomes about the recurrence rate.

폐쇄성 무정자증과 비폐쇄성 무정자증에서 체외수정시술 후의 임신 결과 비교

박찬우,궁미경,양광문,김진영,유근재,서주태,송상진,박용석,강인수,전진현,Park, Chan-Woo,Koong, Mi-Kyoung,Yang, Kwang-Moon,Kim, Jin-Young,Yoo, Keun-Jai,Seo, Ju-Tae,Song, Sang-Jin,Park, Yong-Seog,Kang, Inn-Soo,Jun, Jin-Hyun 대한생식의학회 2003 Clinical and Experimental Reproductive Medicine Vol.30 No.3

Objective: To compare the pregnancy outcomes after in vitro fertilization with intracytoplasmic sperm injection (IVF-ICSI) between obstrucvtive and non-obstrucvtive azoospermia. Methods: From January 1994 to December 2002, 524 patients with obstructive azoospermia (886 cycles) and 163 patients with non-obstructive azoospermia (277 cycles) were included in this study. Microsurgical epididymal sperm aspiration (MESA) or testicular sperm extraction (TESE) in obstructive azoospermia and TESE in non-obstructive azoospermia were perfomed to retrieve sperm, which was used for ICSI and then fertilized embryos were transferred. The results of ICSI - fertlization rate (FR), clinical pregnancy rate (CPR), clinical abortion rate (CAR) and delivery rate (DR) - were statistically analysed in obstructive versus non-obstructive azoospermia. Results: There were no differences in the number of retrieved oocytes, injected oocytes for ICSI and oocyte maturation rate. FR was significantly higher in obstructive than non-obstructive azoospermia (71.7% vs. 61.1%, p<0.001). There was no difference in CPR per embryo transfer cycle. After pregnancy was established, however, CAR was significantly higher in non-obstructive than obstructive azoospermia (25.6% vs. 12.5%, p=0.004). DR per clinical pregnancy cycle was significantly higher in obstructive than non-obstructive azoospermia (78.0% vs. 64.4%, p=0.012). In the karyotype ananlysis of abortus, abnormal karyotypes were found in 75.0% (6/8) of obstructive and 55.6% (5/9) of non-obstructive azoospermia. Conclusion: Our data show significantly higher FR in obstructive than non-obstructive azoospermia. Though there was no differrence in CPR, CAR was significantly higher in non-obstructive than obstructive azoospermia. The abortion may be related to the abnormal karyotype of embryo, but further investigations are necessary to elucidate the cause of clinical abortion in azoospermia.

Artificial Intelligence in Health Care: Current Applications and Issues

박찬우,서성욱,Kang Noeul,Ko BeomSeok,Choi Byung Wook,Park ChangMin,Chang Dong Kyung,김휘영,Kim Hyunchul,이현나,Jang Jinhee,Ye Jong Chul,Jeon Jong Hong,Seo Joon Beom,Kim Kwang Joon,Jung Kyu-Hwan,Kim Namkug,Paek Se 대한의학회 2020 Journal of Korean medical science Vol.35 No.42

In recent years, artificial intelligence (AI) technologies have greatly advanced and become a reality in many areas of our daily lives. In the health care field, numerous efforts are being made to implement the AI technology for practical medical treatments. With the rapid developments in machine learning algorithms and improvements in hardware performances, the AI technology is expected to play an important role in effectively analyzing and utilizing extensive amounts of health and medical data. However, the AI technology has various unique characteristics that are different from the existing health care technologies. Subsequently, there are a number of areas that need to be supplemented within the current health care system for the AI to be utilized more effectively and frequently in health care. In addition, the number of medical practitioners and public that accept AI in the health care is still low; moreover, there are various concerns regarding the safety and reliability of AI technology implementations. Therefore, this paper aims to introduce the current research and application status of AI technology in health care and discuss the issues that need to be resolved.

난관 폐쇄에 기인한 불임 환자에서 난관 개통술의 효용성

박찬우,차선화,양광문,한애라,유지희,송인옥,김혜옥,강인수,궁미경,이경상,Park, Chan-Woo,Cha, Sun-Hwa,Yang, Kwang-Moon,Han, Ae-Ra,Yoo, Ji-Hee,Song, In-Ok,Kim, Hye-OK,Kang, Inn-Soo,Koong, Mi-Kyoung,Lee, Kyung-Sang 대한생식의학회 2010 Clinical and Experimental Reproductive Medicine Vol.37 No.4

목적: 불임을 주소로 내원한 환자들을 대상으로 자궁 난관 조영술을 이용한 난관 불임 선별검사에서 난관 막힘의 소견을 보인 경우 선택적 난관 조영술을 시행 후 실패 시 난관 개통술을 시행하여 난관 불임치료에 있어 난관 개통술의 효용성을 알아보고 난관 막힘 부위 및 형태에 따른 난관 개통률을 비교하고자 하였다. 연구방법: 난관 불임 선별검사로서 자궁 난관 조영술을 시행하였으며 자궁 난관 조영술 상 난관 막힘 소견을 보인 215명의 342개의 난관을 대상으로 후향적 연구를 진행하였다. 결과: 난관 개통술을 시행하여 342개의 난관 가운데 248개의 난관이 개통되어 72.5%의 난관 개통률을 보였다. 막힘 부위에 따른 난관 개통률은 근위부 83.8% (197/235예), 협부 45.6% (47/103예), 원위부 100% (4/4예)를 보여 자궁-난관 접합부에 가까운 막힘 일수록 높은 개통률을 보였다. 막힘 형태에 따른 개통률은 점진형은 92.3% (157/170예), 오목형은 80.2% (69/86예), 볼록형은 25.5% (22/86예)의 난관 개통률을 보였다. 난관 막힘 부위와 형태를 종합하여 볼때 난관 근위부 점진형 막힘의 경우 91.6% (143/156예)의 높은 개통률을 보인 반면 난관 협부 볼록형 막힘의 경우에는 개통률이 11.3% (6/53예)에 불과하였다. 난관 개통에 성공한 156명 가운데 98명에서 임신에 성공하여 62.7%의 임신율을 보였다. 결론: 난관 개통술은 자궁 경부를 통한 시술로 수술적 방법이나 체외수정시술의 난자 채취에 비해 덜 침습적인 방법으로 입원치료가 필요하지 않으며 비교적 적은 비용으로 불임의 원인을 극복할 수 있는 장점이 있어 난관 원인에 의한 불임 환자에서 우선적으로 시행해 볼 수 있는 효과적인 치료 방법이라 할 수 있다. Objective: To evaluate the significance and efficacy of trans-cervical fallopian tube catheterization (TFTC) in diagnosis and optimal treatment modality for tubal blockage. Methods: The retrospective study was performed in those underwent TFTC from January 2005 to December 2009. A total of 342 fallopian tubes in 215 patients which showed tubal blockage in hysterosalpingography (HSG), were subjected to TFTC. Recanalization rate (RR) was compared according to portion of tubal blockage; proximal, isthmic and distal portion and blockage type; tapering, concave, and convex type. Results: In total, RR was 72.5% (248/342 tube). According to the portion of tubal blockage, RR was 83.8% in proximal, 45.6% in isthmic and 100% in distal portion. RR was 92.3% in tapering, 80.2% in concave and 25.5% in convex type, respectively. There were 98 pregnancies in 156 patients after successful recanalization, which shows 62.7% pregnancy rate. Conclusio: TFTC were capable of recanalizing tubal blockage in 248 of 342 tubes in 156 of 215 patients (72.5%). The RR was increased with proximal portion and tapering type tubal blockage.