• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.182-185
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• 2005

Satellite cameras are calibrated before launch in detail and in general, but it cannot be guaranteed that the geometry is not changing during launch and caused by thermal influence of the sun in the orbit. Modem satellite imaging systems are based on CCD-line sensors. Because of the required high sampling rate the length of used CCD-lines is limited. For reaching a sufficient swath width, some CCD-lines are combined to a longer virtual CCD-line. The images generated by the individual CCD-lines do overlap slightly and so they can be shifted in x- and y-direction in relation to a chosen reference image just based on tie points. For the alignment and difference in scale, control points are required. The resulting virtual image has only negligible errors in areas with very large difference in height caused by the difference in the location of the projection centers. Color images can be related to the joint panchromatic scenes just based on tie points. Pan-sharpened images may show only small color shifts in very mountainous areas and for moving objects. The direct sensor orientation has to be calibrated based on control points. Discrepancies in horizontal shift can only be separated from attitude discrepancies with a good three-dimensional control point distribution. For such a calibration a program based on geometric reconstruction of the sensor orientation is required. The approximations by 3D-affine transformation or direct linear transformation (DL n cannot be used. These methods do have also disadvantages for standard sensor orientation. The image orientation by geometric reconstruction can be improved by self calibration with additional parameters for the analysis and compensation of remaining systematic effects for example caused by a not linear CCD-line. The determined sensor geometry can be used for the generation? of rational polynomial coefficients, describing the sensor geometry by relations of polynomials of the ground coordinates X, Y and Z.

• Journal of Chest Surgery
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• 제29권3호
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• pp.346-349
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• 1996

This 32 year old female patient underwent left radical mastectomy due to ductal carcinoma on May 1990, and treated with FAM (5-fluorouracil, Adriamycin and Mitomycin C) regimen postoperatively. However, right cervical Iymph node enlargement and facial edema progressively developed since December 199). On April 1994, operation was performed, and findings were as followes; x4$\times$5$\times$7 to 1 : 1 $\times$ 1 cm sized multiple enlarged and hyperemic Iymph nodes were scatterred throughout submandibular area to the junction of superior vents cave and pericardium, and partially invaded both anterior segmental lobe, sternum and both distal tip of clavicles. After radical dissection of the nodes of neck and mediastinal nodes, and wedge resection of both anterior segments of lung, and partial resection of both clavicle tips and total sternum. The both innominate veins and superior vena cava were partially obstructed by invaded cancer SVC reconstruction was done with preclotted 10$\times$ 10$\times$ 18mm Y shap d woven Dacron graft, which was anastomosed to the point of the junction of subclavian vein and jugular vein after cross clamping both veins and 2cm above the pericardial junction with one arm clamp. After maintaining blood drainage to the SVC from the right side, left innominate vein was anastomosed with 4-0 Prolene continuous running suture. Bone cement was used for resected sternal portion and clavicular ends were fixed to postal portion with 18 Gauge wires. The patient was treated with radiation and chemotherapy after discharge, and there were no evidence of regrowing of the mass nor obstruction of the graft inspite of no antithrombotic therapy.

• 구강회복응용과학지
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• 제16권2호
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• pp.123-132
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• 2000

The field of maxillofacial prosthetics is concerned with the prosthetic reconstruction of missing head and neck tissue. Currently, facial prostheses are usually applied in cases of defects caused by the surgical removal of tumors or congenital defects. While silicone has been most widely used for the reconstruction of missing maxillofacial defects, it does not have ideal physical properties. Therefore, bonding a thin polyurethane sheet to silicone prostheses was recommended. In this case skin adhesives were used for the retention of maxillofacial prostheses. But retention of devices has always been problematic. The contributions of implants can be made to solve these problems. Implants have reduced the need for adhesive use, simplifying cleaning procedures and thus extending the life of the prostheses. For implant-retained prostheses, retentive matrix is necessary to hold attachments and/or magnets. The retentive matrix is usually fabricated with autopolymerizing acrylic resin or visible light- polymerized resin. The purpose of this study was to compare the adhesion-in-peel force of silicone adhesive to autopolymerizing acrylic resin and polyurethane sheet with two different surface textures : pumice polish only or retention groove, and three surface primers : Dow corning 1205 primer or Dow corning S-2260 primer or FactorII A-304 primer, and two polymerization methods : room temperature or dry heat oven. The t-peel bond strength of specimens was determined as described in ASTM Standard D1876-72. The results were statistically analyzed using the ANOVA test, multiple range test and t-test The results were as follows. 1. The t-peel bond strength of A-304 primer was the highest and statistically higher than that of S-2260(p<0.05). 2. The t-peel bond strength of specimens with retention groove was statistically higher than that of specimens polished with pumice(p<0.05). 3. The t-peel bond strength of specimens polymerized in dry heat oven was statistically higher than that of specimens in room temperature(p<0.01).

• 대한의용생체공학회:의공학회지
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• 제21권3호
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• pp.225-231
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• 2000

표면에 의한 3차원 재구성 방법 중 Delaunay 삼각형 분할 방법은 기존의 기하학적 연결성 문제를 해결하고 영상의 질도 높은 것으로 평가받고 있다. 그러나 이 방법은 윤곽선의 위치에 따른 비 입체적 연결성 문제를 갖고 있다. 본 논문에서는 PC환경에서 이러한 문제를 개선한 Delaunay 삼각형 분할 재구성 방법을 제안하였다. 제안된 방법은 기존의 방법에서 나타나는 '비 입체(non-solid)‘ 사면체의 효과적인 처리를 위하여 수정된 External Voronoi Skeleton(EVS)을 이용한 제거 알고리즘을 사용하였다. 이를 적용한 결과. 원 객체 형태에 영향을 주지 않으면서 '비 입체' 사면체만이 제거됨을 확인할 수 있었다. 그리고 재구성된 영상의 표면이 사면체로 촘촘하게 연결되므로 복잡한 형태를 갖는 입체의 표면을 효과적으로 재구성할 수 있었다.

• 디지털콘텐츠학회 논문지
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• 제10권3호
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• pp.381-388
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• 2009

논문에서는 3D 스캔 자료에서 추출한 실루엣(silhouette)의 윤곽선(contour edge)이나 주름변(crease edge)의 정보에 나타난 불필요한 노이즈를 제거하는 방법을 제안한다. 석탑 문화재는 석조물 재질의 특징상 울퉁불퉁한 표면 정보를 가지며, 또한 오랜 세월의 풍화작용에 의한 훼손과 데이터 수집 시 나타날 수 있는 기술적 오류에 의해 실루엣에 단발성 선분 형태의 많은 잡음이 나타난다. 따라서 실루엣의 정보에서 노이즈처럼 보이는 단발성 변들을 제거하면 또렷한 석탑 자체의 실루엣을 얻을 수 있다. 선분의 연속성을 세는 알고리듬을 고안하여 길이가 3개 이하인 윤곽선이나 주름변을 제거하였다. 임계값(threshold)을 사용하는 기존의 실루엣 추출방법과 비교하여, 새로이 제안한 방법은 더욱 효과적이고 정확한 실루엣을 얻을 수 있었다. 제안한 노이즈 제거 방법은 석탑 문화재의 경우뿐 아니라 정보의 변형이나 오류에 의해 잘못된 단발성 주름변을 가지는 다른 경우에 대해서도 응용될 수 있다.

• 한국콘텐츠학회논문지
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• 제15권11호
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• pp.313-321
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• 2015

Hip FAI 진단과 수술 계획 시 Hip FAI MRI 검사시 3D 영상을 추가로 활용하여 CT 영상으로 이루어지는 Hip Clock face 영상을 MRI 3D 영상으로 대체할 수 있는지 비교 평가 하였다. Hip 자기공명 영상검사(MRI)와 3D Hip 컴퓨터 단층 촬영(CT)을 동시 시행한 환자 31명 (남: 21명 평균연령: 35세 여: 10명 평균연령: 40.3세)을 대상으로 분석하였으며, 영상평가는 정형외과 전문의 1명과 영상의학과 전문의 1명이 MR과 CT modality에서 Hip joint articular transverse ligament의 6 o'clock을 중심으로 Superior을 12 o'clock, Labrum의 전면을 3 o'clock, 반대쪽을 9 o'clock로 기술하는 Clock face을 재구성 한 후 11 o'clock에서 A. retinacular vessel, B. head neck junction, 12 o'clock A. Epiphyseal line, B. Cam lesion, 1,2,3,4 o'clock의 Cam lesion, Posterior Cam lesion확인 여부를 리커트(Likert scale) 5점 척도로 평가하였다(Independent t-test p<0.05). 리커드 척도 결과 11 o'clock A. retinacular vessel MR 평균 값 $3.69{\pm}1.0$, CT 평균값 $2.8{\pm}0.78$이며 통계적으로 유의하였다(p<0.001). B. head neck junction은 두 평가자간 차이가 없었다(p<0.416). 12 o'clock A. Epiphyseal line MR 평균값 $3.54{\pm}1.00$, CT 평균값 $4.5{\pm}0.62$이었다(p<0.000). B. Cam lesion은 두 평가자간 차이가 없었다(p<0.532). 1,2,3,4 o'clock 의 Cam lesion과 Posterior Cam lesion은 통계적으로 유의하지 않았다(p<0.656, p<0.658). weighted Kappa 검증 결과 11 o'clock A.retinacular vessel CT K값이 0.663으로 가장 낮은 일치도였으며, 각각의 평가 항목의 일치도 평가 결과 매우 높은 결과로 두 평가자간 높은 신뢰도를 보여주었다.

• Journal of International Society for Simulation Surgery
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• 제3권2호
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• pp.80-83
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• 2016

A 37-year-old male was assaulted and complained of severe periorbital swelling. Physical examination revealed that there were limitation of eyeball movement on upper gaze, diplopia, and hypoesthesia on the infraorbital nerve innervating region. Three-dimensional (3D) computed tomography (CT) of facial bone exhibited the fracture of orbital floor accompanying the significant amount of orbital contents' herniation extending to the far posterior part. To recover the orbital volume and restore orbital floor without threatening the optic nerve, preoperative simplified simulation was applied. The posterior margin of the fractured orbit was delineated with simulation technique using cross-linkage between the coronal and sagittal sections based on the referential axial view of the CT scans. Dissection, reduction of orbital contents, and insertion of the absorbable mesh plate molded after the prefabricated template by the simulation technique was performed. Extensive orbital floor defect was successfully reconstructed and there were no serious complications. The purpose of this report is to emphasize the necessity of preoperative simulation in case of restoring the extensive orbital floor defect.

• 디지털산업정보학회논문지
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• 제10권3호
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• pp.237-247
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• 2014

This paper describes a 2D discrete-time wavelet transform for which the Q-factor is easily specified. Hence, the transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. The tunable Q-factor wavelet transform (TQWT) is a fully-discrete wavelet transform for which the Q-factor, Q, of the underlying wavelet and the asymptotic redundancy (over-sampling rate), r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The TQWT can also be used as an easily-invertible discrete approximation of the continuous wavelet transform. The transform is based on a real valued scaling factor (dilation-factor) and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its oversampling rate (redundancy), with modest oversampling rates (e. g. 3-4 times overcomplete) being sufficient for the analysis/synthesis functions to be well localized. Therefore, This method services good performance in image processing fields.

• Geomechanics and Engineering
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• 제12권3호
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• pp.483-503
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• 2017

Uncertainty is a fact belonging to engineering practice. An important uncertainty that sets geotechnical engineering is the variability associated with the properties of soils or, more precisely, the characterization of soil profiles. The reason is due largely to the complex and varied natural processes associated with the formation of soil. Spatial variability analysis for the study of the stability of natural slopes, complementing conventional analyses, is able to incorporate these uncertainties. In this paper the characterization is performed in back-analysis for a case of landslide occurred to verify afterwards the presence of the conditions of shear strength at failure. This approach may support designers to make more accurate estimates regarding slope failure responding, more consciously, to the legislation dispositions about slope stability evaluation and future design. By applying different kriging techniques used for spatial analysis it has been possible to perform a 3D-slope reconstruction. The predictive analysis and the areal mapping of the soil mechanical characteristics would support the definition of priority interventions in the zones characterized by more critical values as well as slope potential instability. This tool of analysis aims to support decision-making by directing project planning through the efficient allocation of available resources.

• 산업경영시스템학회지
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• 제41권4호
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• pp.123-130
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• 2018

Triangulation is one of the fundamental problems in computational geometry and computer graphics community, and it has huge application areas such as 3D printing, computer-aided engineering, surface reconstruction, surface visualization, and so on. The Delaunay refinement algorithm is a well-known method to generate quality triangular meshes when point cloud and/or constrained edges are given in two- or three-dimensional space. In this paper, we propose a simple but efficient algorithm to triangulate Voronoi surfaces of Voronoi diagram of spheres in 3-dimensional Euclidean space. The proposed algorithm is based on the Ruppert's Delaunay refinement algorithm, and we modified the algorithm to be applied to the triangulation of Voronoi surfaces in two ways. First, a new method to deciding the location of a newly added vertex on the surface in 3-dimensional space is proposed. Second, a new efficient but effective way of estimating approximation error between Voronoi surface and triangulation. Because the proposed algorithm generates a triangular mesh for Voronoi surfaces with guaranteed quality, users can control the level of quality of the resulting triangulation that their application problems require. We have implemented and tested the proposed algorithm for random non-intersecting spheres, and the experimental result shows the proposed algorithm produces quality triangulations on Voronoi surfaces satisfying the quality criterion.