• Archives of Plastic Surgery
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• v.38 no.3
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• pp.257-262
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• 2011

Purpose: In neurofibromatosis patients, complete surgical excision of the mass is almost impossible and surgical treatment usually consists of multiple serial excisions that only result in a debulking effect. Remnant tumor mass has a gravitational effect on facial soft tissues that leads to sagging of skin and soft tissue, and eventually, facial disfigurement and asymmetry. The purpose of our surgical method is to perform soft tissue lifting with longer lasting effect with less surgical risk of damaging facial nerve and vessels. With external fixation using K-wire or surgical screw, the procedure only called for a short incision length and had additional adhesive properties that enabled anchoring of soft tissue in a lifted position for a longer postoperative period. Methods: A total of 5 neurofibromatosis patients (NF-1) visited our clinic for mass reduction and face lifting. The age of patients ranged from 13 to 42 (mean 28.8 years), and most patients had a long history of multiple excisions in the past. Face lifting was performed in 2 different areas, the periorbital area in 3 patients, and the midface in 2 patients. The materials used in fixation of retaining ligament were K-wire (n=3) and titanium screw (n=2). Results: Follow up period was from 5 month to 3 years and 1 month (mean=2 years and 1 month). All patients conveyed satisfaction with the results and no major complications were reported. The lifting effect lasted for as long as 3 years, and there were no complaints of relapse of soft tissue depression or sagging within the operated area. 1 patient (M/13) needed secondary k-wire insertion and additional mass excision in 1 year and 10 months postoperatively due to tumor growth. In two patients with K-wire fixation, mild dimpling and tenderness were observed in the follow up period, but in about 2 months postoperatively, dimpling was relieved and there was no need for removal of fixating material. Conclusion: Surgical lifting in neurofibromatosis patients can be challenging, for mass excision cannot be done completely and gravitational effect by residual mass can be persistent. External fixation of the retaining ligament in patients with neurofibromatosis can give satisfactory results-for incision length is relatively shorter, and the lifting effect can last longer compared to other various face lifting techniques.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.129-137
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• 2013

A force calibration of a nanoindenter and a 3D morphology observation of indenters were carried out in this study. A microbalance calibrated with standard weights was used for measuring the loads generated by a nanoindenter. The indentation load could be calibrated from the ratio of measured and generated loads and the first contact load also could be detected from the microbalance data. By analyzing atomic force microscopy images of two indenters, curvature radii of apexes were determined by $19.71{\pm}3.03$ and $1043.94{\pm}50.91$ nm, respectively, for the nearly new indenter A and the severly worn indenter B. Corresponding bluntness depths were estimated by 1.22 and 64.56 nm for the both indenters by overlapping their profiles on the perfect pyramidal shape. In addition, nanoindentation curves obtained from a fused silica reference material with the both indenters showed a depth difference corresponding to the bluntness depth difference along the indentation depth axis. By shifting amounts of the bluntness depths along the horizontal axis, whole nanoindentation curves overlapped on themselves and resulted in nanohardness values consistent within 1.11 % without considering the complex indenter area function of each indenter.

• Journal of Chest Surgery
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• v.37 no.2
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• pp.139-145
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• 2004

This study describes our surgical results of transventricular complete repair of tetralogy of Fallot in infants. Material and Method: Eight hundred and forty children underwent complete repair of TOF between January 1990 and April 2002 in our institute. One hundred sixty infants of them were included to this survey. Mean age at repair was 8.1$\pm$2.6 months (3∼12). Correction was accomplished through a short right ventriculotomy less than 30% of ventricular height in all patients. A transannular patch was necessary in 78 patients (49%). Result: There were four early deaths. There were no late deaths. Follow-up with mean duration of 66 months was completed in all survivors, All patients are currently in New York Heart Association functional class I or II. Twenty patients required late reoperations. Actuarial freedom from reoperation at 1 and 10 years were 94% and 87% respectively. Two-dimensional and Doppler echocardiographic follow-up studies showed good right ventricular function in all patients except three. Conclusion: Our results suggested that early complete repair of TOF yield the acceptable results with low mortality and morbidity. Transventricular repair of intracardiac pathology can be safely applied to these patient population, yielding good postoperative right ventricular function.

• Journal of the Korean earth science society
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• v.28 no.2
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• pp.214-226
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• 2007

Because precipitation is influenced by various atmospheric variables, it is highly nonlinear. Although precipitation predicted by a dynamic model can be corrected by using a nonlinear Artificial Neural Network, this approach has limits such as choices of the initial weight, local minima and the number of neurons, etc. In the present paper, we correct simulated precipitation by using a multiple linear regression (MLR) method, which is simple and widely used. First of all, Ensemble hindcast is conducted by the PNU/CME Coupled General Circulation Model (CGCM) (Park and Ahn, 2004) for the period from April to August in 1979-2005. MLR is applied to precipitation simulated by PNU/CME CGCM for the months of June (lead 2), July (lead 3), August (lead 4) and seasonal mean JJA (from June to August) of the Northeast Asian region including the Korean Peninsula $(110^{\circ}-145^{\circ}E,\;25-55^{\circ}N)$. We build the MLR model using a linear relationship between observed precipitation and the hindcasted results from the PNU/CME CGCM. The predictor variables selected from CGCM are precipitation, 500 hPa vertical velocity, 200 hPa divergence, surface air temperature and others. After performing a leave-oneout cross validation, the results are compared with the PNU/CME CGCM's. The results including Heidke skill scores demonstrate that the MLR corrected results have better forecasts than the direct CGCM result for rainfall.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5171-5174
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• 2014

Background: The increase in breast cancer awareness and widespread use of mammographic screening has led to an increased detection of (non-palpable) breast cancers that cannot be discovered through physical examination. One of the methods used in the diagnosis of these cancers is vacuum-assisted core biopsy, which prevents a considerable number of patients from undergoing surgical procedures. The aim of this study was to present the results of stereotactic vacuum-assisted core biopsy for suspicious breast lesions. Materials and Methods: Files were retrospectively scanned and data on demographic, radiological and pathological findings were recorded for patients who underwent stereotactic vacuum-assisted core biopsy due to suspicious mammographic findings at the Interventional Radiology Centre of the Florence Nightingale Hospital between January 2010, and April 2013. Statistical analysis was carried out using Pearson's Chi-square, continuity correction, and Fisher's exact tests. Results: The mean age of the patients was 47 years (range: 36-70). Biopsies were performed due to BIRADS 3 lesions in 8 patients, BIRADS 4 lesions in 77 patients, and BIRADS 5 lesions in 3 patients. Mammography elucidated clusters of microcalcifications in 73 patients (83%) and focal lesions (asymmetrical density, distortion) in 15 patients (17%). In terms of complications, 1 patient had a hematoma, and 2 patients had ecchymoses (3/88; 3.3%). The histopathologic results revealed benign lesions in 63 patients (71.6%) and malignant lesions in 25 patients (28.4%). The mean duration of the procedure was 37 minutes (range: 18-55). Although all of the BIRADS 3 lesions were benign, 22 (28.6%) of the BIRADS 4 lesions and all of the BIRADS 5 lesions were malignant. Among the malignant cases, 80% were in situ, and 20% were invasive carcinomas. These patients underwent surgery. Conclusions: In cases where non-palpable breast lesions are considered to be suspicious in mammography scans, the vacuum-assisted core biopsy method provides an accurate histopathologic diagnosis thus preventing a significant number of patients undergoing unnecessary surgical procedures.

• Journal of the Korean Arthroscopy Society
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• v.10 no.2
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• pp.153-158
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• 2006

Purpose: We evaluated the effectiveness of arthroscopic shaving cystectomy by using posteromedial portal for popliteal cyst with the correction of valvular mechanism. Materials and Methods: We had treated 15 cases of popliteal cyst with arthroscopic shaving cystectomy by using posteromedial portal from April 2004 to June 2005. The mean duration of follow up was 15 months (range: $12{\sim}28$). Functional results were based on the Rauschning and Lindgren criteria. We estimated operative time, time for regaining pain-free full range of motion and checked sonography for recurrence of the cyst at 12 months after the surgery. Results: The functional results by Rauschning and Lindgren criteria were rated Grade 0 or Grade 1 in all cases at last follow up. The average operation time was 45 minutes (range: $35{\sim}70$). All cases regained pain-free full range of motion within five days after surgery and range of motion was also normal at last follow up. There were no recurrence and no walking disturbance in all cases. Conclusion: Arthroscopic shaving cystectomy by using posteromedial portal is one of the effective alternative method of the treatment for popliteal cyst and it is also useful to correct the valvular mechanism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.664-668
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• 2018

Free-standing structures that are especially high are more likely to receive brain attacks caused by lightning. Since special structures are generally part of national industrial structures, lightning strikes mostly cause socio-economic damage. Lightning protection facilities are installed to prevent such lightning damage, but in 2015, support cables on West Sea bridges were hit by lightning, causing a lot of economic damage. Accordingly, the design of a lightning protection system shall establish protective measures after analyzing the risk of debris falling onto the structure. In this thesis, lightning strikes are analyzed directly in relation to the modeling system that operates the actual information collection system for lightning strikes, depending on the location of the tall, free-standing structures, and practical lightning hazard information is provided by a meteorological station. In addition, we propose monitoring and applying a probability correction rate to the calculation of the lightning risk based on the number of lightning strikes directly reaching the ground in order to obtain an effective lightning risk assessment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.3
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• pp.217-226
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• 2007

Purpose: Distraction osteogenesis is considered to take favorable effect on the TMJ and be beneficial to prevent the relapse after the mandibular advancement of Class II malocclusion patient. This is the report with literature review on the mandibular advancement in the patients showing preoperative condylar resorption and who need larger amount of advancement. Patients and method: Distraction osteogenesis using intraoral device was performed for three mandibular hypoplasia patients (one male and two females). All patients were adult over 18 years old. The patients showed condylar bony resorption preoperatively. The distraction was performed intraorally with modified SSRO. After 7 days of latency period, activation was performed at the rate of 1.0 mm/day with twice turn. The devices were removed after 4-8 month consolidation period. Results: Total advancement of mandible was average 13 mm. One patient showed openbite immediately after removal of distraction device. It took long time to guide the openbite with elastics. The comparison between cephalometries immediately after device removal and postoperative six month revealed average 3.4 mm relapse. This means that mandibular advancement with distraction osteogenesis needs overcorrection and elastic rehabilitation even after enough consolidation periods. Conclusion: Larger amount of mandibular advancement could be achieved with distraction osteogenesis in severe mandibular hypoplasia with condylar resorption. However, some relapse was found during the follow-up period and the over correction is considered to be needed. The effect of distraction osteogenesis seems to be investigated with long-term follow-up.

• Progress in Medical Physics
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• v.10 no.3
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• pp.125-131
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• 1999

T$_1$/T$_2$ weighted images are being used to give the characteristic contrast among the various tissues and the norma;/abnormal tissues. Abnormalities in tissues, in general, accompany the biochemical changes and eventually structural ones in which results in the change in T$_1$ and T$_2$ relaxation times of water protons. It has been suggested that the mapping of T$_1$/T$_2$ values may serve as a possible tool for the quantitative evaluation of the degree of abnormality. On reconstructing T$_1$/T$_2$ maps(or any other MR parametric map), only corresponding variables are to be varied, such as TE for T$_2$, TI or TR for T$_1$ and b-factor for diffusion images. But often the receiver gain is taken for the optimal usage of A/D converter, so that the set of the image data has different receiver gain. It must be corrected before any attempt to reconstruct the maps. Here we developed method of correcting receiver gain variation effect, using the standard deviation of noise on individual image. The resultant T$_1$ and T$_2$ values were very comparable to the other reported values.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.48-48
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• 2011

본 연구에서는 미래 기후변화가 하천 및 호소수질에 미치는 영향을 평가하고자 유역 수문-수질 모의가 가능한 SWAT(Soil and water assessment tool) 모형과 호소수질 모의가 가능한 WASP(Water Quality Simulation Program) 모형을 연계운영하여 충주호를 포함하는 충주댐 유역($6,642.0km^2$)에 적용하였다. 이를 위해 IPCC(Intergovernmental panel on climate change)에서 제공하는 A1B 배출시나리오를 포함하는 MIROC3.2 hires 모형의 결과로부터 충주댐 유역의 총 6개 기상관측소에 대한 과거 30년(1997~2006) 실측자료를 바탕으로 미래 온도와 강수에 대한 편이보정(Bias correction) 및 Change Factor Method로 상세화(Downscaling)하여 미래 기후자료(2020s, 2050s, 2080s)를 생산하였다. 미래 연평균 온도는 기준년도인 2000년에 비해 최대 $+4.8^{\circ}C$(2080s)의 온도증가를 보였으며, 강수량의 경우 여름과 가을 강수량이 다소 감소하였으나 연평균 강수량은 최대 +34.4%(2080s) 증가하는 것으로 전망되었다. 먼저, SWAT 모형을 이용한 기후변화에 따른 댐 유입량은 39.8%(2080s) 증가는 것으로 분석되었으며 유역의 유출특성 변화로 인한 유사량은 지표유출변화에 기인하여 봄과 겨울에 증가하는 경향과 함께 -14.5%(2020s) ~ +27.3%(2080s)의 변화를 보이는 것으로 분석되었다. 영양물질에 대한 오염부하량은 2080s에서 T-N이 증가추세를 보이며 최대 87.3% 까지 증가하는 반면, T-P는 유사량과 유사한 변화패턴을 보이며 최대 48.4%까지 감소하는 것으로 분석되었다. 호소수질 모델링을 위한 충주호의 Segment 구성은 충주댐1 지점에서부터 충주댐4 지점까지 전체 수표면적 $65.7km^2$에 대하여 상층과 하층 총 760개로 구성하였으며, SWAT 모형에 의한 충주호 유입하천 소유역에서의 미래 유출 및 영양물질 자료를 WASP 모형의 초기값으로 입력하여 수체 내의 BOD, Chl-a, T-N, T-P 변화 분석을 실시하였다. 이와 같이 지구 온난화에 의한 기후변화는 강우특성 변화에 따른 가뭄과 홍수 등 극한 기상현상의 발생, 유역 물순환 체계 변화를 야기 시키므로서 수자원 부존량 변화에 영향을 미칠 뿐만 아니라 기온상승에 따른 수온변화, 비점오염물질의 거동에도 변화를 초래하여 하천 및 호소 수질에 큰 영향을 미칠 것으로 판단된다.