• 디지털콘텐츠학회 논문지
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• 제12권2호
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• pp.151-156
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• 2011

CT검사 후 재구성 영상 처리 기법인 Ray-sum 기법과 Shaded Surface Display(이하 SSD)기법을 분석 및 영상평가를 하여 위암 환자의 입체적인 정보 제공의 유용성 여부를 확인하고자 하였다. 위암환자 20명을 대상으로 64-MDCT를 이용하여 raw data(원시데이터)를 획득한 후 영상 재구성 처리를 하였다. 분석 결과 Ray-sum과 SSD재구성 영상모두 해부학적 구조를 정확히 묘사하는 것으로 평가 받았고, 영상의 정확도 평가에서 Ray-sum, SSD재구성 영상 대부분에서 병변의 위치가 위장 내시경과 일치하였으며 6cm이상에서 오차가 더 있음을 알 수 있었다. 또한 병변에 대한 영상판독결과와 내시경 및 병리학적 소견의 일치도가 높음을 알 수 있었다.

• Archives of Reconstructive Microsurgery
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• 제8권1호
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• pp.15-21
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• 1999

Soft tissue defect on heel area of the foot present difficult problems particularly because of anatomic property of plantar surface of the foot. There is a paucity of available local tissue in the foot for coverage. In addition to having little expandable tissue, the foot's plantar surface has a unique structure, making its replacement especially challenging. Plantar skin is attached to the underlying bone by fibrous septa, preventing shear of the soft-tissue surfaces from the underlying skeleton. Plantar surface of foot is in constant contact with the environment. Protective sensibility also would be maintained or restored in the ideal reconstruction. So the ideal flap for reconstruction of the heel should include thin, durable hairless skin with potential for reinnervation. The aim of this article is to present a clinical experience of free lateral arm neurosensory flap for reconstruction of the heel. From March 1995 to December 1997, a total 16 lateral arm free flaps were performed to soft tissue defects on the weight-bearing area of the hindfoot. we used tibial nerve as recepient nerve in 11 and calcaneal branch of tibial nerve in 5 for restoration of sensibility of flap. All cases survived completely. A static two-point discrimination of 14 to 34mm was detected in the flap. Radial nerve palsy which was caused by hematoma in donor site occured in one case, but recorverd in 3 weeks later completely. In conclusion, the lateral arm free flaps are versatile, reliable and sensible cutaneous flap and especially indicated for soft tissue defect on plantar surface of the hindfoot which are not good indications for other better-known flaps.

• 한국정보통신학회논문지
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• 제12권11호
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• pp.2077-2082
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• 2008

최근 MRI와 CT와 같은 의료영상에서의 진보한 기술은 의사들에게 상세한 해부학적 정보를 제공하게 하여 그들의 진단 능력을 향상시키고 있다. 일반적으로 보다 상세한 정보를 얻기 위해서는 많은 수의 MRI이미지를 필요로 한다. 그러나 일반 병원에서 접하는 MRI 기계의 성능이 우수하지 않은 경우가 많고 따라서 획득되는 이미지의 수가 적다. 결과적으로 적은 수의 슬라이스를 이용해 3D surface를 재구성하게 되면 퀄리티가 낮아지는 문제가 발생한다. 본 논문에서는 적은 수의 슬라이스를 이용하여 높은 퀄리티의 3D surface를 얻는 방법을 제안한다. 이를 위한 알고리즘은 먼저 원하는 영역의 경계를 찾아서 그 경계선들의 점을 찾는다. 이러한 점들로부터 Radial Basis Function을 이용해서 점들을 모두 지나는 음함수 곡면 수식을 생성한다. 생성된 음함수 곡면수식으로부터 Marching cube 알고리즘을 이용하여 렌더링 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.643-648
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• 2011

This paper deals with the ESM(equivalent source method) with the continuation of acoustic near-field for NAH(near-field acoustic holography) to overcome the finite measurement aperture effect and reconstruct the normal velocity on an arbitrarily shaped structure surface. The continuation method is an extension of the measured sound field into a region outside and is based on the Green's function relating acoustic quantities on the two conformal surfaces. This algorithm is not limited to planar surfaces and can be applied to arbitrarily shaped surfaces. The ESM is an alternative approach of BEM-based NAH for the reconstruction on a general structure. In ESM the acoustic field is represented by a set of point sources located over a surface that is close to the structure surface. The simulation results of this study shows that the reconstruction error of particle velocity on the source surface is 11% and 16% for planar and cylindrical sources separately.

• 한국진공학회지
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• 제3권3호
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• pp.269-274
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• 1994

Tersoff 포텐셜을 사용한 에너지 최소화테크닉에 의하여 컴퓨터 시뮬레이션함으로써 다이아몬드 (100)과 (110) 표면의 구조와 표면에너지를 구하였다, 다이아몬드(100)면과 (110)면의 reconstruction pattern 은 각각 (1$\times$1)과 (2$\times$1)이며 표면에너지는 각각 6,671.3 erg/cm2 와 4,032.0 erg/cm2 인 것으로 계산되었다 (100)면의 surface reconstruction 은 첫 번째 원자층과 두 번째 원자층간의 간격이 [100] 방 향으로 수축되는 것으로 나타났다. 한편 (110)면의 surface reconstruc-tion은 주로 첫 번째 원자층에서 의 원자들은 [001] 방향으로 dimerization 한는 것과 첫 번째 원자층과 두 번째 원자층간의 간격이 [110] 방향으로 dimerization 하는 것과 첫 번째 원자층과 두 번째 원자층간의 간격이 [110] 방향으로 수축되 는 것으로 나타났다. 그밖에 표면의 각 원자층의 stress 성분들이 구해졌으며 그것들이 표면흡착에 미치 는 효과 등이 토의되었다.

• 전기학회논문지
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• 제66권1호
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• pp.107-113
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• 2017

Unlike regular images, there is no ground truth for bio surface images. Result of biosurface imaging is not only significantly affected by the environment and the condition of the bio surface, it requires more detailed expression than regular images. Therefore, unlike algorithms tested on regular images, studies on bio surface images requires a highly precise optimization process. We aim to optimize the graph cut algorithm, known to be the most outstanding among the stereo visions, by considering baseline, lambda, and disparity range. Optimal results were in the range of 1~10 for lambda. The disparity ranged from -30 to -50, indicating an optimal value in a slightly higher range. Furthermore, we verified the tested optimization data using SIFT.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.193-200
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• 2009

Recently, there have been efforts to construct hybrids among the existing methodologies for multiphase flow such as VOF, Level Set, and Front Tracking with the intention of facilitating simulations of general three-dimensional problems. As one of the hybrid method, we have developed the Level Contour Reconstruction Method (LCRM) for general three-dimensional multiphase flows including phase change. The main idea was focused on simplicity and a robust algorithm especially for the three-dimensional case. It combines characteristics of both Front Tracking and Level Set methods. While retaining an explicitly tracked interface using interfacial elements, the calculation of a vector distance function plays a crucial role in the periodic reconstruction of the interface elements in the LCRM method to maintain excellent mass conservation and interface fidelity. In addition, compact curvature formulation is incorporated for the calculation of the surface tension force thereby reducing parasitic currents to a negligible level.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.519-521
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• 2003

Within the paper an approach for the automatic extraction and reconstruction of buildings in urban built-up areas base on fusion of high-resolution satellite image and LIDAR data is presented. The presented data fusion scheme is essentially motivated by the fact that image and range data are quite complementary. Raised urban objects are first segmented from the terrain surface in the LIDAR data by making use of the spectral signature derived from satellite image, afterwards building potential regions are initially detected in a hierarchical scheme. A novel 3D building reconstruction model is also presented based on the assumption that most buildings can be approximately decomposed into polyhedral patches. With the constraints of presented building model, 3D edges are used to generate the hypothesis and follow the verification processes and a subsequent logical processing of the primitive geometric patches leads to 3D reconstruction of buildings with good details of shape. The approach is applied on the test sites and shows a good performance, an evaluation is described as well in the paper.

• Archives of Reconstructive Microsurgery
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• 제7권2호
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• pp.157-164
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• 1998

It has been very difficult to managing partial joint defect in any etiologies, especially in children. Unicondylar defect of the tibial condyle in children reconstructed with proximal fibular head with articular cartilage from 1995. Two kinds of transfering methods were used, peroneal artery pedicled ipsilateral fibula head transposition to defective lateral tibial condyle defect that revealed poor prognosis with gradual absorption of transposed fibular epiphysis. Free vascularized fibular head transplantation with microvascular anastomosis underwent in the case with medial condyle defect of tibia which revealed very satisfactory results. Author can conclude with these clinical experiences: 1. Tranposition without epiphyseal vesssels intact is not sufficient in fibular head osteochondral transplantation in reconstruction of tibial condyle defect. That means peroneal arterial vascular pedicle is not enough for transplanted proximal epiphysis maintains its function on articular surface and growth activity in children. 2. The anterior recurrent tibial artery is one of the most important and easy to utilizing vessel in proximal fibular epiphyseal transplantation. 3. Free vascularized fibular head transplantation is hopeful method in reconstruction of the knee joint in the patient with partial joint defect which has no effective solution in conventional methods.

• 대한기관식도과학회지
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• 제16권2호
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• pp.131-137
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• 2010

Background: Montgomery T-tube is widely used to maintain airway in many cases. Market-available tubes are not always fit to the trachea of each patient and need some modification such as trimming. Complications do happen in prolonged use like tracheostomy tubes. To overcome above limitations, we designed custom-made T-tube using CT data with the aid of 3D reconstruction software. Material and Method: Boundaries were extracted from neck CT data of normal person and processed by surface rendering methods. Real laryngotracheal model and tracheal inner surface-mimicking tube model were made with plaster and rubber. The main tube was designed by accumulation of circles or simple closed curves made from boundaries. Stomal tube was made by accumulation of squares due to limitation of software. Measurement data of tracheal lumen were used to custom-made T-tubes. Tracheal lumen residing portion (vertical limb) was made like circular cylinder or simple closed curved cylinder. Stomal portion (horizontal limb) was designed like square cylinder. Results: Custom made T-tube with cylindric vertical limb and horizontal limb of square cylinder was designed. Conclusion: CT data was helpful in making custom made T-tube with 3D reconstruction technique. If suitable materials are available, commercial T-tube can be printed out from 3D printers.