• Investigative and Clinical Urology
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• 제59권6호
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• pp.410-415
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• 2018

Purpose: Despite meticulous techniques, surgical complications continue to be problematic in kidney transplant recipients. Role of routine stenting to reduce complications is controversial. In this study, we compare incidence of early urological complications, lymphoceles, urinary tract infections (UTI) and graft function; with or without double-J stenting. Materials and Methods: All patients who underwent live related donor renal transplantation from February 2014 to February 2016 were included. Transplants prior to February 2015 were without routine stenting; subsequent transplants were with routine stenting. Patients with neurogenic bladder, previously operated bladder and delayed or low urinary output were excluded. Followup was for at least three months. Descriptive statistics was performed for all parameters. Chi square test and Fisher's Exact test were used for qualitative variables. For quantitative variables, Mann-Whitney test was used to test median difference and independent samples t-test for mean difference. The p-value ${\leq}0.05$ was considered significant. Results: We analysed 74 patients (34 stented and 40 non-stented). There was no difference in the incidence of urinary leak, anastomotic obstruction, lymphoceles or UTI (p>0.4 for all comparisons). However, mean estimated glomerular filtration rate at sixth day, 14th day, one month and two months were 76.1 vs. 61.5 (p=0.025), 72.1 vs. 56.6 (p=0.005), 79.4 vs. 63.1 (p=0.002) and 82.0 vs. 63.3 (p=0.001) in the stented versus non-stented groups. Conclusions: Placement of ureteral stent in renal transplant does not significantly affect the incidence of early urinary complications or UTI. However, graft function is significantly better in stented recipients, at least in the short term.

• 한국가스학회지
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• 제22권6호
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• pp.28-33
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• 2018

최근 들어 정부는 도시가스 미공급지역 해소 및 소규모 공급지역의 경제성 확보를 위해 준저압 공급을 확대하고 있다. 주로 중앙 저장 탱크에서 매설 배관으로 각 세대에 공급하고 있는데 타공사에 의한 매설 배관의 파손 시 가스의 누출을 차단할 방법으로 배관 파손에 의한 과류를 차단할 수 있는 밸브의 필요성이 대두되고 있다. 이 연구를 위해 System CFD Code인 Flownex를 이용하였으며 실제 과류차단밸브에 해당되는 Component를 개발 완료하였다. 본 연구를 진행하면서 Flownex의 정확도를 검증하기 위해 실험값과 비교 하였으며 2% 내외의 오차율을 확인하였고 본 연구를 위해 사용이 가능한 것으로 판단되었다. 본 연구에서는 마을 단위의 LPG 공급 배관망을 선정하여 Modeling을 하였으며 주배관에서 세대로 인입되는 가지관의 이음 부위에 임으로 과류차단밸브 Component를 설치하였다. 주 배관에서 세대까지 가장 긴 배관을 선택하여 세대 인입 직전에 배관을 임으로 파손시켜 과류가 발생하도록 시나리오를 정하였다. 배관이 파손됨에 따라 과류가 발생하게 되고 과류차단밸브가 작동하게 되는데 이 때 과류차단 밸브의 작동이 타 배관에 미치는 영향 및 오작동 유무를 분석하였다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제8권6호
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• pp.151-158
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• 2019

캐시 부채널 공격 중 하나인 FLUSH+RELOAD 공격은 높은 해상도와 적은 노이즈로 여러 악성 프로그램에서도 활용되는 등 비밀 정보의 유출에 대한 위험성이 높은 공격이다. 따라서 이 공격을 막기 위해 실시간으로 공격을 탐지하는 기술을 개발할 필요가 있다. 본 논문에서는 프로세서의 PCM (Performance Counter Monitor)를 이용한 실시간 FLUSH+RELOAD 공격 탐지 기법을 제안한다. 탐지 방법의 개발을 위해 우선 공격이 발생하는 동안 PCM의 여러 카운터들의 값들의 변화를 4가지 실험을 통해 관찰하였다. 그 결과, 3가지 중요한 요인에 의해 공격 탐지를 할 수 있다는 것을 발견하였다. 이를 바탕으로 머신 러닝의 logistic regression과 ANN(Artificial Neural Network)를 사용해 결과에 대한 각각 학습을 시킨 뒤 실시간으로 공격에 대한 탐지를 할 수 있는 알고리즘을 개발하였다. 이 탐지 알고리즘은 일정한 시간동안 공격을 진행하여 모든 공격을 감지하는데 성공하였고 상대적으로 적은 오탐률을 보여주었다.

• Journal of Rhinology
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• 제25권2호
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• pp.123-129
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• 2018

Background and Objectives: Endoscopic repair of cerebrospinal fluid (CSF) leak can avoid morbidity of open approaches and has shown a favorable success rate. Free mucosal graft is a good method, and multi-layered repair is more favorable. The inferior turbinate has been commonly utilized for the free mucosal graft, but we newly designed it as a bone-periosteal-mucosal composite graft for multilayered reconstruction. Subjects and Method: Four subjects with a skull base defect were treated with this method. The inferior turbinate was partially resected including the conchal bone and was trimmed according to defect size. Both bony parts and periosteum were preserved on the basolateral side of the mucosa as a composite graft. The graft was applied to the defect site using an overlay technique. Results: All cases were successfully repaired without any complications. Three of them had a defect size greater than 10-12 mm, and the graft stably repaired the CSF leakage. Conclusion: Endoscopic repair of CSF leakage using inferior turbinate composite graft is a simple and easy method and would be favorable for defect sizes greater than 10 mm.

• Journal of Gastric Cancer
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• 제20권4호
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• pp.376-384
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• 2020

Purpose: The role of prophylactic abdominal drainage in total gastrectomy is not well-established. This study aimed to evaluate the efficacy of abdominal drainage in the prevention and management of major intra-abdominal complications after total gastrectomy for gastric carcinoma. Materials and Methods: We retrospectively reviewed the data of 499 patients who underwent total gastrectomy for gastric carcinoma in a high-volume institution. The patients were divided into drainage and non-drainage groups and compared for the development and management of major intra-abdominal complications, including anastomotic leak, abdominal bleeding, abdominal infection, and pancreatic fistulas. Results: The drainage group included 388 patients and the non-drainage group included 111 patients. The 2 groups showed no significant differences in clinicopathological characteristics or operative procedures, except for more frequent D2 lymphadenectomies in the drainage group. After surgery, the overall morbidity (drainage group vs. non-drainage group: 24.7% vs. 28.8%, P=0.385) and incidence of major intra-abdominal complications (6.4% vs. 6.3%, P=0.959) did not significantly differ between the two groups. The non-drainage group showed no significant increase in the incidence rate of major intra-abdominal complications in the subgroups divided by age, sex, comorbidity, operative approach, body mass index, extent of lymphadenectomy, and pathological stage. Abdominal drainage had no significant impact on early diagnosis, secondary intervention or reoperation, or recovery from major intra-abdominal complications. Conclusions: Prophylactic abdominal drainage showed little demonstrable benefit in the prevention and management of major intra-abdominal complications of total gastrectomy for gastric carcinoma.

• 공업화학
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• 제32권1호
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• pp.102-109
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• 2021

Recently, an interest in risk calculation methods has been increasing in Korea due to the establishment of classification code for explosive hazardous area on gas facility (KGS CODE GC101), which is based on the international standard of classification of areas - explosive gas atmospheres (IEC 60079-10-1). However, experiments to check for leaks of combustible or toxic gases are very difficult. These experiments can lead to fire, explosion, and toxic poisoning. Therefore, even if someone tries to provide a laboratory for this experiment, it is difficult to install a gas leakage equipment. In this study we find out differences among actual experiments, CFD by using FLACS and calculation based on classification code for explosive hazardous area on gas facility (KGS CODE GC101) by comparing to each other. We develpoed KGS HAC (hazardous area classification) program which based on KGS GC101 for convenience and popularization. As a result, actual gas leak, CFD and KGS HAC are showing slightly different results. The results of dispersion of 1.8 to 2.7 m were shown in the actual experiment, and the CFD and KGS HAC showed a linear increase of about 0.4 to 1 m depending on the increase in a flow rate. In the actual experiment, the application of 3/8" tubes and orifice to take into account the momentum drop resulted in an increase in the hazardous distance of about 1.95 m. Comparing three methods was able to identify similarities between real and CFD, and also similarities and limitations of CFD and KGS HAC. We hope these results will provide a good basis for future experiments and risk calculations.

• 한국주조공학회지
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• 제42권4호
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• pp.218-225
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• 2022

본 연구에서는 고압 다이캐스팅 (High pressure die-casting, HPDC)을 통해 알루미늄 합금 (상업코드: ALDC12종)으로 수소 자동차용 부품 (Air pressure control valve housing, APCVH)을 제조하였으며 주조품의 기밀성을 향상시키기 위해 유기 함침액을 개발하였다. 개발된 2종류의 유기 함침액 (INNO-series, 한국)과 상용 합침액 (P601, 일본)을 사용하여 함침공정 조건 및 후 처리에 따른 미세결함과 기밀성을 비교 평가하였다. 컴퓨터 단층촬영 및 3차원 X-선 현미경 분석을 통해 함침된 알루미늄 주조품의 결함제어 및 성능 개선을 확인하였다. 또한, 함침 공정 후 기밀성 시험에서 INNO-01이 함침된 시료의 경우 성능 개선율이 70%인 것으로 확인하였다. 따라서, 개발된 유기 함침액은 상용 가능하며 다이캐스팅 제품의 기밀성 향상에 도움이 될 것으로 판단된다.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.174-183
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• 2022

Management of traumatic skull base fractures and associated complications pose a unique reconstructive challenge. The goals of skull base reconstruction include structural support for the brain and orbit, separation of the central nervous system from the aerodigestive tract, volume to decrease dead space, and restoration of the three-dimensional appearance of the face and cranium with bone and soft tissues. An open bicoronal approach is the most commonly used technique for craniofacial disassembly of the bifrontal region, with evacuation of intracranial hemorrhage and dural repair performed prior to reconstruction. Depending on the defect size and underlying patient and operative factors, reconstruction may involve bony reconstruction using autografts, allografts, or prosthetics in addition to soft tissue reconstruction using vascularized local or distant tissues. The vast majority of traumatic anterior cranial fossa (ACF) injuries resulting in smaller defects of the cranial base itself can be successfully reconstructed using local pedicled pericranial or galeal flaps. Compared with historical nonvascularized ACF reconstructive options, vascularized reconstruction using pericranial and/or galeal flaps has decreased the rate of cerebrospinal fluid (CSF) leak from 25 to 6.5%. We review the existing literature on this uncommon entity and present our case series of n = 6 patients undergoing traumatic reconstruction of the ACF at an urban Level 1 trauma center from 2016 to 2018. There were no postoperative CSF leaks, mucoceles, episodes of meningitis, or deaths during the study follow-up period. In conclusion, use of pericranial, galeal, and free flaps, as indicated, can provide reliable and durable reconstruction of a wide variety of injuries.

• 융합보안논문지
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• 제22권3호
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• pp.41-55
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• 2022

기술보호의 중요성이 날로 강조됨에 따라 기술보호를 위한 다양한 보호조치들이 수행되고 있으나 기술유출을 위한 시도가 끊이지 않고 있으며 이에 대한 대안으로 기술유출 범죄에 대해 보다 강력한 처벌이 사회적으로 요구되고 있는 실정이다. 이러한 사회적 요구에 맞춰 그간 꾸준히 처벌 기준이 상향되어 왔으며 현재도 추가적인 강화 내용을 담은 입법안들이 국회에 계류 중인 상황이다. 하지만 범죄에 대한 억제력을 실질적으로 제고하기 위해서는 처벌 기준을 강화하는 것만으로는 충분하지 않으며 처벌의 확실성이 높아졌을 때야 비로소 그 효과를 온전히 발휘될 수 있다. 따라서 본 논문에서는 처벌 자체의 강화적인 부분보다는 현 제도 하에서 처벌의 확실성을 높이기 위한 방안을 모색하는데 초점을 맞췄으며 이를 위해 기술유출 형사사건 중 무죄 사건을 중심으로 사례 및 원인을 유형별로 분석함으로써 기술유출 형사사건에서의 무죄율이 일반 형사사건 대비 높은 이유를 도출해보고 이를 토대로 부당한 무죄사건을 줄이기 위한 개선 고려사항들을 논의하고자 하였다.

• Journal of Chest Surgery
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• 제57권2호
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• pp.152-159
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• 2024

Background: Anastomotic leakage (AL) following esophagectomy represents a serious complication that often results in prolonged hospitalization and necessitates repeated interventions, including nothing-by-mouth (NPO) restriction, endoscopic vacuum therapy (EVT), or surgical repair. In this study, we evaluated the patterns and outcomes of AL treatment. Methods: We retrospectively reviewed the medical records of patients who underwent esophagectomy for esophageal cancer at a single center between 2003 and 2020. Of 3,096 examined cases, 181 patients (5.8%) with AL were included in the study: 114 patients (63%) with cervical anastomosis (CA) and 67 (37%) with intrathoracic anastomosis (TA). Results: The incidence of AL was 11.9% in the CA and 3.2% in the TA group (p<0.001). Among patients with CA who developed AL, 87 (76.3%) were managed with NPO, 15 (13.2%) with EVT, and 12 (10.5%) with surgical repair. Over 90% of patients with cervical AL resumed an oral diet by the time of discharge, regardless of treatment method. Among patients with TA and AL, 36 (53.7%) received NPO, 25 (37.7%) underwent EVT, and 6 (9%) required surgery. Of these, 34 patients who were managed with NPO and 19 with EVT could resume an oral diet. However, only 2 patients who underwent surgery resumed an oral diet, and 2 patients required additional EVT. Conclusion: Although patients with CA displayed a higher incidence of AL, their rate of successful oral intake exceeded that of those with TA, regardless of treatment method. Among patients exhibiting AL with TA, EVT was more commonly employed than in CA cases, and it appears effective.