• Archives of Reconstructive Microsurgery
• /
• v.20 no.1
• /
• pp.51-56
• /
• 2011

During below knee amputation, the amputation stump must be covered with well-vascularized and sensate soft tissue. Many flaps can be used for this purpose, but available reconstructive options are limited. We performed reverse flow ALT flap elevation on two patients with below knee amputations to reconstruct defects in the stumps. The sizes of the defects in the stumps were $4{\times}16$ cm and $5{\times}5$ cm, respectively. The most distal portion of the defects were located 20 cm and 16 cm lateral to the knee joint in a curve, respectively. The size of the elevated flap was $5{\times}18$ cm for case 1 and $18{\times}10$ cm for case 2. The respective pivot points of the pedicles were 7 cm and 6 cm above the patella and the respective lengths of the pedicles were 17 cm and 16 cm. In both cases, venous congestion occurred on the second postoperative day and the flap distal to 10 cm or more from below the knee joint was necrotized at the second postoperative week. Surgeons should be cautious when using a reverse ALT flap to reconstruct a soft tissue defect located 10 cm or more distal from below the knee joint. Since a pedicle longer than 15 cm may develop partial necrosis of the flap, simultaneous application of antegrade venous drainage is recommended.

• KIPS Transactions on Software and Data Engineering
• /
• v.12 no.5
• /
• pp.229-236
• /
• 2023

Since 3D printed medical implant parts usually have surface defects, it is necessary to inspect the surface after manufacturing. In order to automate the surface inspection, it is effective to 3D scan the implant and reconstruct it as a scan model such as a point cloud. When constructing a scan model, the characteristics of the shape and material of the implant must be considered because it has characteristics different from those of general 3D printed parts. In this paper, we present a method to reconstruct the 3D scan model of a 3D printed metal bone-plate that is one kind of medical implant parts. Multiple partial scan data are produced by multi-view 3D scan, and then, we reconstruct a scan model by alignment and merging of partial data. We also present the process of the scan model reconstruction through experiments.

• Geophysics and Geophysical Exploration
• /
• v.23 no.1
• /
• pp.38-49
• /
• 2020

Full-waveform inversion (FWI) is an optimization process of fitting observed and modeled data to reconstruct high-resolution subsurface physical models. In acoustic FWI (AFWI), pressure data acquired using a marine streamer has mainly been used to reconstruct the subsurface P-wave velocity models. With recent advances in marine seismic-acquisition techniques, acquiring multi-component data in marine environments have become increasingly common. Thus, AFWI strategies must be developed to effectively use marine multi-component data. Herein, we proposed an AFWI strategy using horizontal and vertical particle-acceleration data. By analyzing the modeled acoustic data and conducting sensitivity kernel analysis, we first investigated the characteristics of each data component using AFWI. Common-shot gathers show that direct, diving, and reflection waves appearing in the pressure data are separated in each component of the particle-acceleration data. Sensitivity kernel analyses show that the horizontal particle-acceleration wavefields typically contribute to the recovery of the long-wavelength structures in the shallow part of the model, and the vertical particle-acceleration wavefields are generally required to reconstruct long- and short-wavelength structures in the deep parts and over the whole area of a given model. Finally, we present a sequential-inversion strategy for using the particle-acceleration wavefields. We believe that this approach can be used to reconstruct a reasonable P-wave velocity model, even when the pressure data is not available.

• The Bulletin of The Korean Astronomical Society
• /
• v.45 no.1
• /
• pp.48.3-48.3
• /
• 2020

Using redshift-space distortion, I reconstruct the growth history as a smooth function using model independent methods. Assuming general relativity, I obtain the expansion history independently of the dark energy model, and test it to the supernovae data. The results are consistent with general relativity as gravity and the cosmological constant as dark energy, although interestingly negative dark energy densities are not ruled out by the data at z~0.7 to 1.

• Journal of Korea Multimedia Society
• /
• v.19 no.2
• /
• pp.224-232
• /
• 2016

The methodology to visualize the shape of blood vessel and its blood flow have been attracting as a very interesting problem to forecast and examinate a disease in thrombus precursor protein. May previous visualization researches have been appeared for designing the blood vessel and also modeling the blood flow using a doppler imaging technique which is one of nondestructive testing techniques. General visualization methods are to depict the blood flow obtained from doppler effects with fragmentary stream lines and also visualize the blood flow model using volume rendering. However, these visualizeation techniques have the disadvantage which a set of small line segments does not give the overall observation of blood flows. Therefore, we propose a visualization system which reconstruct the continuity of the blood flow obtained from doppler effects and also visualize the blood flow with the vector field of blood particles. This system will use doppler phase difference from medical equipments such as OCT with low penetration and reconstruct the blood flow by the curvature estimation from vector field of each blood particle.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.25 no.4
• /
• pp.412-417
• /
• 2015

Kinect sensor has two output data which are produced from red green blue (RGB) sensor and depth sensor, it is called color image and depth map, respectively. Although this device's prices are cheapest than the other devices for three-dimensional (3D) reconstruction, we need extra work for reconstruct a smooth 3D data and also have semantic meaning. It happened because the depth map, which has been produced from depth sensor usually have a coarse and empty value. Consequently, it can be make artifact and holes on the surface, when we reconstruct it to 3D directly. In this paper, we present a method for solving this problem by using implicit surface representation. The key idea for represent implicit surface is by using radial basis function (RBF) and to avoid the trivial solution that the implicit function is zero everywhere, we need to defined on-surface point and off-surface point. Based on our simulation results using captured face as an input, we can produce smooth 3D face and fill the holes on the 3D face surface, since RBF is good for interpolation and holes filling. Modified anisotropic diffusion is used to produced smoothed surface.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.4
• /
• pp.91-98
• /
• 2017

Electrical impedance tomography is a nondestructive imaging technique to reconstruct unknown conductivity distribution based on applied current data and measured voltage data through an array of electrodes attached on the periphery of a domain. In this paper, an inverse method based on truncated singular value decomposition is proposed to solve the inverse problem with the generalized Tikhonov regularization and to reconstruct the conductivity distribution. In order to reduce the inverse computational time, truncated singular value decomposition is applied to the inverse term after the generalized regularization matrix is taken out from the inverse matrix term. Numerical experiments and phantom experiments have been performed to verify the performance of the proposed method.

• Archives of Reconstructive Microsurgery
• /
• v.8 no.1
• /
• pp.28-34
• /
• 1999

The need for reconstruction of large bone, soft tissue defect of mandible has greater emphasis due to development of industry, traumatic accident and increase of tumor. The mandibular reconstruction had greatly progressed through the first and the second World Wars. The Fibular free flap by using microscope was reported in 1970 and many maxillofacial reconstructive surgeons had used. In 1988, Dr. Hidalgo first reported mandibular reconstruction by using fibular free flap. Mandibular reconstruction by using fibular free flap has several advantages. First, it provides up to 25 cm of bone, enough to reconstruct any length of mandible defect. Second, a skin island, based on a septocutaneous blood supply, is available in a size large enough to simultaneously reconstruct internal and external soft tissue defect. Third, The fibular donor site morbidity is low, fourth, it provides a esthetic effect of mandible line. And finally bone viability is good. The Fibular osteocutaneous free flap was performed after COMMANDO operation due to squamous cell cancer in oral cavity (15 cases). Therefore we report out successful operation of the mandible reconstruction by using fibular osteocutaneous free flap.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.436-442
• /
• 2009

Tomography images reconstructed from conebeam CT make it possible to observe inside of the projected object without any damage, and so it has been widely used in the industrial and medical fields. Recent advanced imaging equipment can produce high-resolution CT images. However, it takes much time to reconstruct the obtained large dataset. To reduce the time to reconstruct CT images, we propose an accelerating method using GPU (graphics processing unit). Reconstruction consists of mainly two parts, filtering and back-projection. In filtering phase, we applied 4ch image compression method and in back-projection phase, computation reduction method using depth test is applied. The experimental results show that the proposed method accelerates the speed 50 times than the CPU-based program optimized with OpenMP by utilizing the high-computing power of parallelized GPU.

• The KIPS Transactions:PartB
• /
• v.15B no.2
• /
• pp.81-86
• /
• 2008

This paper discusses the problem of partial object recognition in image databases. We propose the method to reconstruct and estimate partially occluded shapes and regions of objects in images from overlapping and cutting. We present the robust method for recognizing partially occluded objects based on symmetry properties, which is based on an ellipse of objects. Our method provides simple techniques to reconstruct occluded regions via a region copy using the symmetry axis within an object. Since our method relies on reconstruction of the object based on the symmetry rather than statistical estimates, it has proven to be remarkably robust in recognizing partially occluded objects in the presence of scale changes, rotation, and viewpoint changes.