• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.461-463
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• 2002

Image quality and selection of optimized window for good quality reconstruction in coronary angiography using multi-detector row CT (MDCT) have not been studied by heart rate and its variation. Therefore, the effect of heart rate and its variation was systemically analyzed. Eighty-three patients were undergone contrast-enhanced coronary angiography using MDCT. In this study, sixty cases were enrolled. Two radiologists graded image quality as follows: 4, excellent; 3, good; 2, fair; l, bad. The starting points of the reconstruction window were chosen at seventy and forty percent of R wave interval. Optimized window was scored as 1 when 40% reconstruction was better quality than 70%, as 2 when 40% reconstruction is same as 70%, and as 3 when 70% reconstruction was better than 40%. Regression analysis was performed. The range of variation of beats per minute (BPM) was well correlated with image quality (r=-0.55, p=0.000), however correlation with optimized window percentage was not statistically significant (p=0.969). By contraries, median value of BPM was comparatively well correlated with optimized window grade (r=-0.24, p=0.086). Median value of BPM was not well correlated with image quality (r=0.l70, p=0.l97). Image quality is more affected by variation of heart rate (VHR) than by higher heart rate. Selection of optimized reconstruction window for good image quality is mainly affected by heart rate and there is a tendency that systolic phase reconstruction is better in image quality than diastolic reconstruction in higher heart rate.

• Archives of Plastic Surgery
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• 제41권3호
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• pp.264-270
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• 2014

Background The technique of delayed-immediate breast reconstruction includes immediate insertion of a tissue expander, post-mastectomy radiation, followed by reconstruction. The aesthetic benefits of delayed-immediate reconstruction compared to delayed reconstruction are postulated but remain unproven. The purpose of this study was to compare aesthetic outcomes in patients following delayed and delayed-immediate autologous breast reconstruction. Methods A retrospective analysis was performed of all patients who underwent delayed or delayed-immediate autologous breast reconstruction by the senior author from 2005 to 2011. Postoperative photographs were used to evaluate aesthetic outcomes: skin quality, scar formation, superior pole contour, inferior pole contour, and overall aesthetic outcome. Ten non-biased reviewers assessed outcomes using a 5-point Likert scale. Fisher's Exact and Wilcoxon-Mann-Whitney tests were used for comparative analysis. Results Patient age and body mass index were similar between delayed (n=20) and delayed-immediate (n=20) cohorts (P>0.05). Skin and scar quality was rated significantly higher in the delayed-immediate cohort (3.74 vs. 3.05, P<0.001 and 3.41 vs. 2.79, P<0.001; respectively). Assessment of contour-related parameters, superior pole and inferior pole, found significantly improved outcomes in the delayed-immediate cohort (3.67 vs. 2.96, P<0.001 and 3.84 vs. 3.06, P<0.001; respectively). Delayed-immediate breast reconstruction had a significantly higher overall score compared to delayed breast reconstructions (3.84 vs. 2.94, P<0.001). Smoking and the time interval from radiation to reconstruction were found to affect aesthetic outcomes (P<0.05). Conclusions Preservation of native mastectomy skin may allow for improved skin/scar quality, breast contour, and overall aesthetic outcomes following a delayed-immediate reconstructive algorithm as compared to delayed breast reconstruction.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.892-896
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• 2005

This paper collected 132 schools reconstruction projects in central Taiwan, which received the most serious damage from the Chi-Chi Earthquake. Regression analysis was implemented to build the prediction model of the cost and the duration for the collected projects. It is found that the cubic regression models are capable for predicting the cost and the duration of the projects contracted by the central agency of which the contracting awarding approach was based on the most advantageous tendering (MAT) approach. On the other hand, power regression models are capable for predicting the cost and the duration of the projects contracted through the low bid tendering (LBT) approach. It is also found that the performance of the regression prediction model differs in accordance with organizations that contracted the reconstruction projects.

• 한국음향학회지
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• 제20권6호
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• pp.9-16
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• 2001

본 논문에서는 음파를 이용하여 덕트 내 길이 방향으로의 불균일 단면적을 역문제적으로 측정하는 방법에 대해서 연구하였다. 음파를 사사용하여 덕트 단면적을 구하는 이론 및 실험방법 등에 대해서 많은 연구가 되어왔으나, 본 연구에서는 덕트 내 충격응답을 구하고 이를 재구성 알고리즘에 대입하여 덕트 내 단면적을 구하는 방법을 채택하였다. 충격 가진을 통하여 덕트 내 충격응답을 구하는 기존 방법의 문제점을 살펴보았고, 광대역 가진 방법을 새로 제안하였다. 실험 및 이론적 고찰을 통하여 새로운 방법이 기존의 방법보다 면적 재구성 오차가 적음을 보였다. 덕트 단면적을 재구성 할 때의 오차 원인과 불규칙 잡음에 의한 오차범위를 파악하기 위하여 오차해석을 수행하여 음파를 이용한 면적 재구성 방법의 적용범위 및 대상을 명확히 하였다.

• 보존과학회지
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• 제32권4호
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• pp.561-570
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• 2016

이 연구는 심곡사칠층석탑의 해체와 재조립에 3차원 영상분석 기법을 적용하여 원형에 가깝게 보수한 기술적 사례로써 의미가 있다. 석탑의 해체와 재조립 과정에서 전체적인 변형상태와 변위를 분석하였으며 구조적 안정성 검토를 통하여 재조립에 따른 변형을 최소화하였다. 또한 석탑의 원위치도 재검토하여 보수에 적용하였다. 재조립에 앞서 오염된 석재의 표면은 과학적 표면세정을 통해 이끼류와 지의류 등을 제거하였고, 석탑의 지반은 강회를 이용한 판축과 유사한 형식으로 다짐하여 보강하였다. 이 결과는 석탑의 해체와 재조립 과정에 중요한 자료로 활용될 수 있을 것이다.

• Korean Journal of Radiology
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• 제23권7호
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• pp.752-762
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• 2022

Objective: To compare a deep learning-based reconstruction (DLR) algorithm for pediatric abdominopelvic computed tomography (CT) with filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Materials and Methods: Post-contrast abdominopelvic CT scans obtained from 120 pediatric patients (mean age ± standard deviation, 8.7 ± 5.2 years; 60 males) between May 2020 and October 2020 were evaluated in this retrospective study. Images were reconstructed using FBP, a hybrid IR algorithm (ASiR-V) with blending factors of 50% and 100% (AV50 and AV100, respectively), and a DLR algorithm (TrueFidelity) with three strength levels (low, medium, and high). Noise power spectrum (NPS) and edge rise distance (ERD) were used to evaluate noise characteristics and spatial resolution, respectively. Image noise, edge definition, overall image quality, lesion detectability and conspicuity, and artifacts were qualitatively scored by two pediatric radiologists, and the scores of the two reviewers were averaged. A repeated-measures analysis of variance followed by the Bonferroni post-hoc test was used to compare NPS and ERD among the six reconstruction methods. The Friedman rank sum test followed by the Nemenyi-Wilcoxon-Wilcox all-pairs test was used to compare the results of the qualitative visual analysis among the six reconstruction methods. Results: The NPS noise magnitude of AV100 was significantly lower than that of the DLR, whereas the NPS peak of AV100 was significantly higher than that of the high- and medium-strength DLR (p < 0.001). The NPS average spatial frequencies were higher for DLR than for ASiR-V (p < 0.001). ERD was shorter with DLR than with ASiR-V and FBP (p < 0.001). Qualitative visual analysis revealed better overall image quality with high-strength DLR than with ASiR-V (p < 0.001). Conclusion: For pediatric abdominopelvic CT, the DLR algorithm may provide improved noise characteristics and better spatial resolution than the hybrid IR algorithm.

• 대한두개안면성형외과학회지
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• 제25권4호
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• pp.179-186
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• 2024

Background: Auricle reconstruction is among the most challenging procedures in plastic and reconstructive surgery, and the choice of framework material is a critical decision for both surgeons and patients. This meta-analysis compared the outcomes of autologous auricle reconstruction using costal cartilage with those of alloplastic reconstruction using porous polyethylene implants. Methods: A literature review was conducted using the PubMed and Embase databases to retrieve articles published between January 2000 and June 2024. The outcomes analyzed included postoperative complications such as framework exposure, infection, skin necrosis, hematoma, and hypertrophic scars, as well as patient satisfaction. The proportions of reconstructive outcomes from each selected study were statistically analyzed using the "metaprop" function in R software. Results: Fourteen articles met our inclusion criteria. The group undergoing polyethylene implant reconstruction exhibited higher rates of framework exposure, infection, and skin necrosis, whereas the autologous reconstruction group experienced higher rates of hematoma and hypertrophic scars. Of all the complications, framework exposure was the only one to show a statistically significant difference between the two groups (p< 0.0001). In terms of patient satisfaction, those who underwent autologous cartilage reconstruction reported a higher rate of satisfaction, although this difference did not reach statistical significance in the meta-analysis (p= 0.076). Conclusion: There is no statistically significant difference in postoperative complications such as infection, hematoma, skin necrosis, and hypertrophic scars between auricle reconstructions using autologous costal cartilage and those using polyethylene implants. However, reconstructions with polyethylene implants show a significantly higher rate of framework exposure.

• Applied Microscopy
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• 제39권4호
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• pp.349-354
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• 2009

TFT-LCD의 구조불량이 발생한 박막 트랜지스터에 대해서 집속이온빔 가공장치(Dual-beam FIB/SEM)를 이용하여 연속절편법(Serial sectioning)과 일련의 연속적인 2차원 주사전자현미경 이미지를 얻었고, IMOD 소프트웨어를 통해서 3차원 구조구현(3D reconstruction) 연구를 하였다. 3차원 구조구현 결과, Gate막과 Data막이 접합되어 있는 불량이 관찰되었다. 두 막이 접합되어서 ON/OFF 역할을 하는 Gate의 기능이 상실되었고, Data신호는 Drain을 통해서 투명전극에 전류를 공급하여 계속 빛나는 선 불량(line defect)이 발생한 것으로 판단된다. 이 논문의 결과인 집속이온빔 가공장치(Dual-Beam FIB/SEM)를 이용한 3차원 구조구현 연구와 연속절편법, 주사전자현미경 이미지작업, 이미지 프로세싱에 대한 결과는 향후 연구의 기초자료로 활용될 수 있을 것으로 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1749-1752
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• 2005

For online high accurate reconstruction of an object from an visual information, a linear reconstruction method for multiple images is popular. Basically this method needs many cameras or many different screen shots from different view points. This method, however, has the benefit of less calculation and is adequate for a real time application by comparing other popular method. In this paper, online reconstruction system using more than three cameras is treated. An evaluation method of cameras' position, and of the number is derived for the linear reconstruction method. To decrease errors that are caused from skew of lens, positional error between corresponding points is taken into consideration on the evaluation. The proposed evaluation method enables estimation of the adequate number of cameras and then of feasible view locations. Additionally, repeating search of epipolar lines enables estimation of the hidden point. Comparing with result of an average error analysis, it was confirmed that the proposed methods works effectively.

• 비파괴검사학회지
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• 제22권5호
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• pp.545-556
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• 2002

Algebraic reconstruction technique (ART)과 multiplicative algebraic reconstruction technique (MART)이라는 토모그래피 방법을 이용하여 2상유동에서 기포의 거동을 배침투적으로 분석하였다. 먼저, 컴퓨터 합성 영상장으로 환상유통과 기포유동을 제작하여 2차원 단면의 재건을 시도하였다. 2상유동의 보다 정확한 결과들을 얻기 위하여 두가지 토모그래피 방법이 비교되었다. 그리고, 2상유동에서 기포의 거동을 3차원으로 분석하기 위하여 2개와 3개의 기포가 존재하는 3차원 합성 영상장으로부터 2차원 단면에서 보다 정확한 결과를 보인 MART 재건법에 의해서 밀도 분포 해석을 수행하였다.