• Journal of Korea Multimedia Society
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• v.22 no.12
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• pp.1385-1395
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• 2019

In this paper, we propose a method to fabricate a patient-specific breast implant using MRI images and 3D scan data. Existing breast implants for breast reconstruction surgery are primarily fabricated products for shaping, and among the limited types of implants, products similar to the patient's breast have been used. In fact, the larger the difference between the shape of the breast and the implant, the more frequent the postoperative side effects and the lower the satisfaction. Previous researches on the fabrication of patient-specific breast implants have used limited information based on only MRI images or on only 3D scan data. In this paper, we propose an algorithm for the fabrication of patient-specific breast implants that combines MRI images with 3D scan data, considering anatomical suitability for external shape, volume, and pectoral muscle. Experimental results show that we can produce precise breast implants using the proposed algorithm.

• The Korean Journal of Nuclear Medicine
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• v.17 no.2
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• pp.19-24
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• 1983

The purpose of this study was to develop a method by which the sensitivity of radionuclide liver imaging for detection of liver cirrhosis could be enhanced. Dynamic blood flow scan were performed 21 cases of liver cirrhosis patients by using computerized gamma camera named arterialization index. The results were as follows: 1) Arterialization index were higher in liver cirrhosis comparing to normal value 0.33 and its mean is 2. 02. 2) Comparing to static liver scan, higher sensitivity in dynamic hepatic blood flow scan for detection of liver cirrhosis. Sensitivity for detection of liver cirrhosis is over 90%. 3) There are no correlation between arterialization index and serum albumin level. The use of hepatic dynamic blood flow scan proved effective in detection of liver cirrhosis. However, the test may be used as an aid in distinguishing between normal and pathologic livers.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.195-198
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• 2007

GOCI(Geostationary Ocean Color Imager) is the core paryload of the geostationary satellite COMS(Communication, Ocean and Meteological Satellite) for ocean monitoring. It is scheduled to be launched at the end of 2008. GOCI observes ocean color around the Korean Peninsula over $2500km{\times}2500km$ area. Whole field of view is divided into 16 solts and scan mechanism enables to point each slot position. Tilted two-axis scan method is used to observe entire field of view with great pointing stability. Vignetting of the optical system appears when the partial obscuration by intermediate optical components occurs. It leads to the variation of the illumination in the image and gradual fading near the edge of the field. It should be prohibited for the stable radiometric performances. In this work, vignetting analysis of GOCI optical system is performed. For the systematic approach, GOCI optical system is divided into scan mechanism part and telescope part. Vignetting analysis of each part is performed and each result is combined for the overall vignetting performances. The analyzed results can be applied to the selection of slot acquisition angle of scan mechanism to minimize vignetting effects.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.243-250
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• 1998

Reconstruction aspects of spiral scan imaging for ultra fast magnetic resonance imagine(MRI) have been investigated with polar and rectangular coordinates-based reconstruction. For the reconstruction of the spiral scan imaging, acquired data in spiral trjectory should be converted to polar or rectangular grids, where interpolation techniques are used. Various reconstruction algorithms for spiral scan imaging are tested, and reconstructed image qualities are compared with computed phantom. An improved reconstruction algorithm with dc-offset correction in projection domain is proposed, which provides the best reconstructed image quality from the simulation. Image artifact with existing algorithms is completely removed with the proposed method.

• Corrosion Science and Technology
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• v.11 no.3
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• pp.89-95
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• 2012

U.S. Electric Power Research Institute (EPRI) has developed CHECWORKS program and applied it to power plant piping lines since some lines were ruptured by flow-accelerated corrosion (FAC) in 1978. Nowadays the CHECWORKS program has been used to manage pipe wall thinning phenomena caused by FAC. However, various erosion mechanisms can occur in carbon-steel piping. Most common forms of erosion are cavitation, flashing, liquid droplet impingement erosion (LDIE), and Solid Particle Erosion (SPE). Those erosion mechanisms cause pipe wall thinning, leaking, rupturing, and even result in unplanned shutdowns of utilities. Especially, in two phase condition, LDIE damages a wide scope of plant pipelines. Furthermore, LDIE is the major culprit to cause such as power runback by pipe leaking. This paper describes the methodologies that manage wall thinning and also predict LDIE wall thinning area. For this study, current properties of two-phase condition are investigated and LDIE areas are selected. The areas are checked by B-Scan method to detect the effect of wall thinning phenomena.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.113-118
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• 2011

Sequence homology analysis in the substances in the phenomenon of life is to create database by sorting and indexing and to demonstrate the usefulness of informatics. In this paper, Markov models are used in GenScan program to convert the pattern of complex eukaryotic protein sequences. It becomes impossible to navigate the minimum distance, complexity increases exponentially as the exact calculation. It is used scorecard in amino acid substitutions between similar amino acid substitutions to have a differential effect score, and is applied the Markov models sophisticated concealment of the transition probability model. As providing superior method to translate sequences homologous sequences in analysis using blast p, Markov models. is secreted protein structure of sequence translations.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.192-198
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• 2008

Purpose: The scan time reduction helps to yield more accurate results and induce the minimization of patient's motion. Also we can expect that satisfaction of examination will increase. Nowdays medical equipment companies have developed various programs to reduce scan time. We used Onco. Flash (Pixon method, SIEMENS) that is an image processing technique gated cardiac blood pool scan and going to evaluate its clinical usefullness. Materials and Method: We analyzed the 50 patients who were examined by gated blood pool scan in nuclear medicine department of Asan Mediacal Center from June $20^{th}$ 2008 to August $14^{th}$ 2008. We acquired the Full-time (6000 Kcounts) and Half-time (3000 Kcounts) LAO image in same position. And we acquired LVEF values ten times from Full-time, Half-time images acquired by the image processing technique and analyzed its mean and standard deviation values. To estimate LVEF in same conditions, we set automatic location of the LV ROI and background ROI based on same X and Y-axis. Also we performed blinding tests to physician. Results: After making a quantitative analysis of the 50 patients EF values, each mean${\pm}$standard deviation is shown at Full-time image $68.12{\pm}7.84%$, Half- time (acquired by imaging processing technique) $68.49{\pm}8.73%$. In the 95% confidence limit, there was no statistically significant difference (p>0.05). After blinding test with a physician for making a qualitative analysis, there was no difference between Full-time image and Half-time image acquired by the image processing technique for observing LV myocardial wall motion. Conclusion: Gated cardiac blood pool scan has been reported its relatively exact EF measured results than ultrasound or CT. But gated cardiac blood pool scan takes relatively longer time than other exams and now it needs to improve time competitive power. If we adapt Half-time technique to gated cardiac blood pool scintigraphy based on this study, we expect to reduce possible artifacts and improve accessibility as well as flexibility to exam. Also we expect patient's satisfaction.

• Korean Journal of Human Ecology
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• v.21 no.5
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• pp.975-988
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• 2012

Although the pattern development for tight-fitting clothing has been carried out using 3D data on humans, the pattern development using 3D scan data obtained for various postures still remains an interesting subject. In this study, we have developed the 2D pattern using the 3D human body reflecting standing and cycling postures. The 3D scan data of a subject was obtained using Cyberware. 2C-AN program(Triangle simplification and the Runge-Kutta method) was used in the system to reduce the 3D scan data points and to make segmented triangular patches in a plane from 3D data. As results, surface distance and area of each body part of standing and cycling postures were also provided for the future application of the functional clothing construction. The area of center piece on the front (c.front) decreased by $106.45cm^2$(-13.08%) and that of lateral piece(s.back) on the back increased by $144.96cm^2$(18.69%) in the patterns of cycling posture. The girth of neck and waist for the cycling posture increased by 0.88cm (3.92%) and 1.56cm(4.40%) respectively, and the that of thigh decreased by 1.01cm(-2.24%). The differences between the area in the 2D pattern obtained from the 3D scan data and that in the 3D scan surface data for standing and cycling postures were very small($-10.34cm^2$(-0.32%) and $-44.33cm^2$(-1.32%)).

• Clinical and Experimental Pediatrics
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• v.54 no.5
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• pp.212-218
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• 2011

Purpose: The diagnosis of acute pyelonephritis (APN) is often difficult, as its clinical and biological manifestations are non-specific in children. If not treated quickly and adequately, however, APN may cause irreversible renal damage, possibly leading to hypertension and chronic renal failure. We were suspecting the diagnostic value of $^{99m}Tc$-dimercaptosuccinic acid (DMSA) scan by experiences and so compared the results of DMSA scan to those of multi-detector row computed tomography (MDCT). Methods: We retrospectively selected and analyzed 81 patients who were diagnosed as APN by MDCT during evaluation of their acute abdomen in emergency room and then received DMSA scan also for the diagnostic work-up of APN after admission. We evaluated the results of imaging studies and compared the diagnostic value of each method by age groups, <2 years (n=45) and ${\geq}$2 years (n=36). Results: Among total 81 patients with MDCT-proven APN, DMSA scan was diagnostic only in 55 children (68%), while the remaining 26 children (32%) showed false negative normal findings. These 26 patients were predominantly male and most of them, 19 (73.1%) were <2 years of age. Conclusion: DMSA scan holds obvious limitation compared to MDCT in depicting acute inflammatory lesions of kidney in children with APN, especially in early childhood less than 2 years of age. MDCT showed hidden lesions of APN, those were undetectable through DMSA scan in children.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11
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• pp.3519-3533
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• 2000

In a VOD(Video-On-Demand) system, I/O performance and storage requirements are generally more important than computing capability, Due to the development of CPU tecnology, the gap between the performance of processors and desk speed are widening. Therefore, the disk system typically becomes the bohleneck ina VOD system. In order to allevte those effects from physical constramts, disk array system is used. The I/O performance of disk arrays can be improved by the capability of processors, I/O schefuling polcy, the number of member disks in the array, disk block size, block placemet method etc. In this paper, we considered the disk scheduling schemes including EDF( Earliest Deadine First), SCAN, SGAN-EDF, Round-robm. GSS(Grouped Sweeping scheme), and C-SCAN, LOOK, C-LOOK which are variations of SCAN Mamly focusing on those disk scheduling schemes, we performed the simulation in order to compare and eview the perionmance of disk arrays considening seveial related parameters under diverse environments and analyzed the effects of those parameters to the performance.