• 수산해양교육연구
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• 제6권2호
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• pp.190-197
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• 1994

1989년부터 1993년까지 5년동안 우리 나라 주변해역에서 발생한 2513건의 해난사고(海難事故)를 유형(類型), 원인(原因) 및 선종(船種)에 따라 21의 인자(因子)로 분류하고, 이를 주요분분석법(主成分分析法)에 의해 분석(分析)한 결과를 요약하면 다음과 같다. 1. 해난사고(海難事故)의 주된 원인(原因)은 운항부주의(運航不主意), 기관취급불량(機關取扱不良) 등 인적요인(人的要因)에 있으며, 사고(事故) 유형(類型)으로서는 기관고장(機關故障)이, 선종(船種)으로서는 어선(漁船)이 특히 해난사고(海難事故)의 큰 비중을 차지한다. 2. 어선(漁船)의 경우에는 기관고장(機關故障) 등 경미(輕微)한 해난사고(海難事故)가 많은데 비해 화물선(貨物船), 여객선(旅客船), 유조선(油槽船)의 경우에는 좌초(坐礁), 추돌(衝突), 침수(浸水) 등 재산(財産)과 인명(人命)의 피해가 큰 대형해난사고(大型海難事故)가 많은 경향이다. 3. 대형해난사고(大型海難事故)중 좌초(坐礁)와 충돌(衝突)은 그 주된 원인(原因)이 운항부주의(運航不主意) 등 인적요인(人的要因)에 있고, 침수(浸水)와 전복(顚覆)은 인적요인(人的要因)이외에도 기상악화(氣象惡化)나 재질구조결함(材質構造缺陷) 등에 기인(起因)하는 바가 크다.

• 대한두개안면성형외과학회지
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• 제24권3호
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• pp.105-110
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• 2023

Background: Conventional radial forearm free flaps (RFFFs) are known to be safe, but can result in donor site complications. Based on our experiences with suprafascial and subfascial RFFFs, we evaluated the safety of flap survival and surgical outcomes. Methods: This was a retrospective study of head and neck reconstructions using RFFFs from 2006 to 2021. Thirty-two patients underwent procedures using either subfascial (group A) or suprafascial (group B) dissection for flap elevation. Data were collected on patient characteristics, flap size, and donor and recipient complications, and the two groups were compared. Results: Thirteen of the 32 patients were in group A and 19 were in group B. Group A included 10 men and three women, with a mean age of 56.15 years, and group B included 16 men and three women, with a mean age of 59.11 years. The mean defect areas were 42.83 cm² and 33.32 cm², and the mean flap sizes were 50.96 cm² and 44.54 cm² in groups A and B, respectively. There were 13 donor site complications: eight (61.5%) in group A and five (26.3%) in group B. Flexor tendon exposure occurred in three patients in group A and in none in group B. All flaps survived completely. A recipient site complication occurred in two patients (15.4%) in group A and three patients (15.8%) in group B. Conclusions: Complications and flap survival were similar between the two groups. However, tendon exposure at the donor site was less prevalent in the suprafascial group, and the treatment period was shorter. Based on our data, suprafascial RFFF is a reliable and safe procedure for reconstruction of the head and neck.

• 방송공학회논문지
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• 제6권1호
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• pp.41-49
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• 2001

디지털 워터마킹은 워터마크의 성질에 따라 강성 워터마킹(robust watermarking)과 연성 워터마킹(fragile watermarking)으로 분류할 수 있다. 강성 워터마킹은 저작권 보호를 위한 기법이고, 연성 워터마킹은 데이터의 인증/무결성을 위한 기법으로 데이터의 진위를 확인하는 수단으로 이용할 수 있다. 일반적으로 연성 워터마킹은 영상을 변조하거나 위조하였을 때 이전에 삽입되어 있던 워터마크를 검출할 수 없게 되면 영상이 변조나 위조되었다고 판단한다. 영상의 화소 값은 비트의 조합으로 구성되므로 영상의 변조는 비트의 변경을 의미한다고 할 수 있다 따라서, 본 논문에서는 상위 비트 플레인(bit plane)과 하위 비트 플레인의 변조를 판단하기 위해 2개의 워터마크를 삽입하는 연성 워터마킹을 제안한다. 실험결과, 영상에 삽입된 워터마크는 시각적으로 영상 내에서 확인할 수 없으며. 영상에 변조를 가하였을 때 변조의 위치를 확인할 수 있었다.

• Archives of Plastic Surgery
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• 제44권1호
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• pp.26-33
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• 2017

Background The purpose of this study was to assess the correlation between the 2-dimensional (2D) extent of orbital defects and the 3-dimensional (3D) volume of herniated orbital content in patients with an orbital wall fracture. Methods This retrospective study was based on the medical records and radiologic data of 60 patients from January 2014 to June 2016 for a unilateral isolated orbital wall fracture. They were classified into 2 groups depending on whether the fracture involved the inferior wall (group I, n=30) or the medial wall (group M, n=30). The 2D area of the orbital defect was calculated using the conventional formula. The 2D extent of the orbital defect and the 3D volume of herniated orbital content were measured with 3D image processing software. Statistical analysis was performed to evaluate the correlations between the 2D and 3D parameters. Results Varying degrees of positive correlation were found between the 2D extent of the orbital defects and the 3D herniated orbital volume in both groups (Pearson correlation coefficient, 0.568-0.788; $R^2=32.2%-62.1%$). Conclusions Both the calculated and measured 2D extent of the orbital defects showed a positive correlation with the 3D herniated orbital volume in orbital wall fractures. However, a relatively large volume of herniation (>$0.9cm^3$) occurred not infrequently despite the presence of a small orbital defect (<$1.9cm^2$). Therefore, estimating the 3D volume of the herniated content in addition to the 2D orbital defect would be helpful for determining whether surgery is indicated and ensuring adequate surgical outcomes.

• 한국건축시공학회지
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• 제21권3호
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• pp.231-239
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• 2021

4차 산업혁명 시대로 접어들면서 건설산업에서 CCTV, 홈네트워크시스템 및 장비와 같은 정보통신기술(ICT)이 활용되고 있다. 특히 공동주택에서 정보통신기술(ICT)의 자율성을 증대하기 위해 정부는 정보통신 관련법의 개정안을 행정예고하고 기업은 스마트 홈서비스와 같은 기술개발에 집중하고 있다. 또한, 정보통신공사 분야의 국내·외 연구는 대부분 정보통신기술(ICT)과 공사 관리에 관한 연구가 진행된 것을 확인할 수 있었다. 하지만, 정보통신공사의 품질에 영향을 주는 물리적 하자에 관한 연구는 부족한 실정이다. 이에 본 연구는 3개의 국내 건설사 프로젝트관리시스템에 등록된 하자 데이터를 수집하였고 공동주택관리법 시행령의 기준에 따라 분류하였다. 공종별 하자 빈도를 분석했을 때 홈네워크기기공사에서 하자가 88.10%로 가장 많이 발생하였다. 그리고 4개 공종의 하자 유형을 분석한 결과 작동불량이 가장 많이 나타났다. 그에 원인을 분석하고 설계·시공·유지관리 단계로 나누어 예방방안 및 대책을 제시하였다. 본 연구의 결과는 공동주택의 품질을 높이고, 추후 실질적인 하자 저감 대책 및 예방방안에 관련한 연구의 기초 자료로 활용될 수 있을 것이다.

• Journal of Chest Surgery
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• 제46권6호
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• pp.433-438
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• 2013

Background: Surgical repair of post-infarct ventricular septal defect (VSD) is considered one of the most challenging procedures having high surgical mortality. This study aimed to evaluate the outcomes of the surgical repair of post-infarct VSD. Methods: From May 1991 to July 2012, 34 patients (mean age, $67.1{\pm}7.9$ years) underwent surgical repair of post-infarct VSD. A retrospective review of clinical and surgical data was performed. Results: VSD repair involved the infarct exclusion technique using a patch in all patients. For coronary revascularization, 12 patients (35.3%) underwent concomitant coronary artery bypass graft, 3 patients (8.8%) underwent preoperative percutaneous coronary intervention, and 9 patients (26.5%) underwent both of these procedures. The early mortality rate was 20.6%. Six patients (17.6%) required reoperation due to residual shunt or newly developed VSD. During follow-up (median, 4.8 years; range, 0 to 18.4 years), late death occurred in nine patients. Overall, the 5-year and 10-year survival rates were $54.4%{\pm}8.8%$ and $44.3%{\pm}8.9%$, respectively. According to a Cox regression analysis, preoperative cardiogenic shock (p=0.069) and prolonged cardiopulmonary bypass time (p=0.008) were independent predictors of mortality. Conclusion: The early surgical outcome of post-infarct VSD was acceptable considering the high-risk nature of the disease. The long-term outcome, however, was still dismal, necessitating comprehensive optimal management through close follow-up.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.939-944
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• 2002

PD phenomena can be regarded as a deterministic dynamical process where PD should be occurred if the local electric field be reached to be sufficiently high. And thus, its mathematical model can be described by either difference equations or differential equations using several state variables obtained from the time sequential measured data of PD signals. These variables can provide rich and complex behavior of detectable time series, for which Chaos theory can be employed. In this respect, a new PD pattern recognition method is proposed and named as 'Chaotic Analysis of Partial Discharges (CAPD)' for this work. For this purpose, six types of specimen are designed and made as the models of the possible defects that may cause sudden failures of the underground power transmission cables under service, and partial discharge signals, generated from those samples, are detected and then analyzed by means of CAPD. Throughout the work, qualitative and quantitative properties related to the PD signals from different defects are analyzed by use of attractor in phase space, information dimensions ($D_0$ and D2), Lyapunov exponents and K-S entropy as well. Based on these results, it could be pointed out that the nature of defect seems to be identified more distinctively when the CAPD is combined with traditional statistical method such as PRPDA. Furthermore, the relationship between PD magnitude and the occurrence timing is investigated with a view to simulating PD phenomena.

• Journal of the Korean Wood Science and Technology
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• 제22권2호
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• pp.61-70
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• 1994

This study was executed to find the applicability of press drying of tree disk by investigating the shrinkage and drying defect and to form appropriate model by comparing the actual moisture content(MC) and internal temperature in respect of drying time with calculated values based computer simulation to which was applied finite difference method. In press drying disk, heating period, constant drying rate period maintained plateau temperature at 100$^{\circ}C$ and falling drying rate period were significantly distinguished. Actual MC and internal temperature were analogous to those calculated at comparing points. Heat transfer model formed by Fourier's law using specific heat of moist wood and conduction coefficient considering fractional volume of each element of wood cell wall, bound water, free water and air showed applicability as basic data to developing heat expansion, shrinkage and drying stress during press drying. Also mass transfer model formed by Fick's diffusion law using water vapor diffusion coefficient showed applicability. Longitudinal shrinkage was developed by pressure of hot press and tangential shrinkage was restrained by hygrothermal recovery. The heart check, surface check and ring failure were occurred differently in species, but V-shaped crack didn't develop.

• Archives of Plastic Surgery
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• 제39권6호
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• pp.649-654
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• 2012

Background Deep burns of the elbow lead to soft tissue necrosis and infection, with exposure of deep structures. Adequate wound coverage of this area requires thin, pliable, and durable tissue, while optimal functional recovery requires early coverage and functional rehabilitation. We have found 3 types of island flaps that provide reliable coverage for the elbow. Methods A retrospective study was performed on all patients who underwent flap coverage of an elbow defect at our hospital. The patients' data including age, sex, cause of injury, wound dimensions, timing of flap coverage, postoperative elbow motion, and complications were investigated. Results Between 2001 and 2012, 16 patients were treated at our hospital. The mean age was 53.3 years. Three kinds of flaps were performed: 9 latissimus dorsi flaps, 4 lateral arm flaps, and 4 radial forearm flaps. The average defect size was 183.5 $cm^2$ (range, 28 to 670 cm2). Wound coverage was performed at mean duration of 45.9 days (range, 14 to 91 days). The mean postoperative active elbow flexion was $98^{\circ}$ (range, $85^{\circ}$ to $115^{\circ}$). Partial flap failure occurred in 1 latissimus dorsi flap. Minor complications included partial flap loss (11.8%), hematoma (23.5%), seroma (35.3%), and wound infection (5.9%). Conclusions Flap selection for elbow reconstruction is determined by the defect size and the extent of the adjacent tissue injury. Elbow reconstruction using an island flap is a single-staged, reliable, and relatively simple procedure that permits initiation of early rehabilitation, thereby improving a patient's functional outcome.

• 한국전기전자재료학회논문지
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• 제20권1호
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• pp.57-64
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• 2007

One of the cause of insulation failure in power cable is well known by electrical treeing discharge. This is occurred for imposed continuous stress at cable. And this event is related to safety, reliability and maintenance. In this paper, throughout analysis of partial discharge(PD) distribution when occurring the electrical tree, is studied for the purpose of knowing of electrical treeing discharge characteristics according to defects. Own characteristic of tree will be differently processed in each defect and this reason is the first purpose of this paper. To acquire PD data, three defective tree models were made. And their own data is shown by the phase-resolved partial discharge method (PRPD). As a result of PRPD, tree discharge sources have their own characteristics. And if other defects (void, metal particle) exist internal power cable then their characteristics are shown very different. This result Is related to the time of breakdown and this is importance of cable diagnosis. And classification method of PD sources was studied in this paper. It needs select the most useful method to apply PD data classification one of the proposed method. To meet the requirement, we select methods of different type. That is, neural network(NN-BP), adaptive neuro-fuzzy inference system and PCA-LDA were applied to result. As a result of, ANFIS shows the highest rate which value is 98 %. Generally, PCA-LDA and ANFIS are better than BP. Finally, we performed classification of tree progress using ANFIS and that result is 92 %.