• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.39.2-39.2
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• 2014

We present a photometric study of star clusters in the nuclear starburst region of NGC 253 using gVI, YJ, and H band images in the Hubble Space Telescope archive. We find about one thousand star clusters in about 200"x200" field by visual inspection with I<21. We also find about ten thousand star clusters in the same field by automated classification method with magnitude range of 21< I $$\leq_-$$ 24. Ages and masses of star clusters are estimated using spectral energy distribution fitting method. Age distribution of star cluster shows two distinguished young populations with peak ages at 3.5 Myr and 18 Myr. Old populations (>100 Myr) are exist, but their number is small. About thirty young massive star clusters (<10 Myr, ) are found in nuclear region of NGC 253 which are regarded as a result of the recent starburst. Mass function of young star clusters in NGC 253 is somewhat different with those of star clusters in other galaxies. This result suggests that initial cluster mass functions (ICMFs) for star clusters are not universial. Especially ICMF in starburst galaxies may be distinguishable compared with those in normal spiral galaxies. We discuss the implications of these results.

• Journal of Korean Medicine Rehabilitation
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• v.28 no.2
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• pp.121-126
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• 2018

Atypical facial pain is persistent facial pain in the absence of clinical neurological deficit. We experienced two patient who are diagnosed atypical facial pain with Classification of International Headache Society. They were treated by acupuncture at their cervical and facial region. After treatment, their Pain intensity numerical rating scale(PI-NRS) is decreased and EuroQol five dimensions questionnaire(EQ-5D) score is increased. Treatment of acupuncture at cervical and facial region could be effective for easing the clinical symptoms of atypical facial pain. Further studies are needed to find effective treatment for atypical facial pain.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.192-194
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• 2003

Since the details in quasi-homogeneous region will be destroyed from the conventional global image enhancement method such as histogram equalization. This defect is caused by the saturation of gray level in equalization process. So the local histogram equalization for each quasi-homogeneous region will be used in order to improve the details in the region itself. To obtain the quasi- homogeneous regions, the original image must be segmented. Here we applied the watershed transform to the interesting image. Since the watershed transform is based on mathematical morphology, therefore, the regions touch can be effectively separated. Hence two adjacent regions which have the similar gray pixels will be split off. The process will be independently applied to three different spectral images. Then three different colors are assigned to each processed image in order to produce a color composite image. By the proposed algorithm, the result image shows the better perception on image details. Therefore, the high efficiency of image classification can be obtained by using this color image.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.5
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• pp.519-524
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• 2006

Segmentation for the region of nucleus in the image of uterine cervical cytodiagnosis is known as the most difficult and important part in the automatic cervical cancer recognition system. In this paper, the region of nucleus is extracted from an image of uterine cervical cytodiagnosis using the fuzzy grey morphology operation. The characteristics of the nucleus are extracted from the analysis of morphemetric features, densitometric features, colormetric features, and textural features based on the detected region of nucleus area. The classification criterion of a nucleus is defined according to the standard categories of the Bethesda system. The enhanced fuzzy ART algorithm is used to the extracted nucleus and the results show that the proposed method is efficient in nucleus recognition and uterine cervical Pap-Smears extraction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.72-79
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• 2008

The weak point of the artificial neural network(ANN) is that it is easy to fall in local minima when it learns too much nonlinear data. Accordingly, the classification ratio must be low. To overcome this weakness, the hybrid method has been proposed. That is, the ANN learns data selectively after detecting the defect position by the support vector machine(SVM). First, the SVM has been used for determination of the defect position and then the magnitude of the defect has been measured by the ANN. In off-design condition, the operation region of the engine is wide and the nonlinearity of learning data increases. The module system, dividing the whole operating region into reasonably small-size sections, has been suggested to solve this problem. In this study, the proposed algorithm has diagnosed the defects of triple components as well as single and dual components of the gas turbine engine in off-design condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.7
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• pp.601-608
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• 2021

Launch Acceptability Region of Air-to-Surface Guided Bomb is defined as the set of release points in order to reach a target successfully. LAR is consisted of fixed target area and moving target area whether the target maneuvers or not. In this paper, the computational algorithm of LAR is studied for fixed and moving target. First, multi-simulations are performed varying platform, target, and atmospheric environment to attain Min/Max DB. Second, the LAR functions are obtained using regression and classification algorithm. For operational suitability, the algorithm for display of LAR is studied to obtain appropriate LAR. In this progress, the results of LAR are suitable to apply air-to-ground guided bomb for moving target.

• Journal of Radiation Protection and Research
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• v.26 no.2
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• pp.59-66
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• 2001

It is a hot issue to determine the spatial location and shape of tumor boundary in fractionated stereotactic radiotherapy (FSRT). We could get consecutive transaxial plane images from the phantom (paraffin) and 4 patients with brain tumor using helical computed tomography(HCT). K-means classification algorithm was adjusted to change raw data pixel value in CT images into classified average pixel value. The classified images consists of 5 regions that ate tumor region (TR), normal region (NR), combination region (CR), uncommitted region (UR) and artifact region (AR). The major concern was how to separate the normal region from tumor region in the combination area. Relative average deviation analysis was adjusted to alter average pixel values of 5 regions into 2 regions of normal and tumor region to define maximum point among average deviation pixel values. And then we drawn gross tumor volume (GTV) boundary by connecting maximum points in images using semi-automatic contour method by IDL(Interactive Data Language) program. The error limit of the ROI boundary in homogeneous phantom is estimated within ${\pm}1%$. In case of 4 patients, we could confirm that the tumor lesions described by physician and the lesions described automatically by the K-mean classification algorithm and relative average deviation analyses were similar. These methods can make uncertain boundary between normal and tumor region into clear boundary. Therefore it will be useful in the CT images-based treatment planning especially to use above procedure apply prescribed method when CT images intermittently fail to visualize tumor volume comparing to MRI images.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.4
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• pp.235-243
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• 2016

Korea is part of a region of low to moderate seismicity located inside the Eurasian plate with bedrock located at depths less than 30 m. However, the spectral acceleration obtained from site response analyses based on the geologic conditions of inland areas of the Korean peninsula are significantly different from the current Korean seismic code. Therefore, suitable site classification scheme and design response spectra based on local site conditions in the Korean peninsula are required to produce reliable estimates of earthquake ground motion. In this study, site-specific response analyses were performed at more than 300 sites with at least 100 sites at each site categories of $S_C$, $S_D$, and $S_E$ as defined in the current seismic code in Korea. The process of creating a huge database of input parameters - such as shear wave velocity profiles, normalized shear modulus reduction curves, damping curves, and input earthquake motions - for site response analyses were described. The response spectra and site coefficients obtained from site response analyses were compared with those proposed for the site categories in the current code. Problems with the current seismic design code were subsequently discussed, and the development and verifications of new site classification system and corresponding design response spectra are detailed in companion papers (II-development of new site categories and design response spectra and III-Verifications)

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.4
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• pp.245-256
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• 2016

In the companion paper (I - Database and Site Response Analyses), site-specific response analyses were performed at more than 300 domestic sites. In this study, a new site classification system and design response spectra are proposed using results of the site-specific response analyses. Depth to bedrock (H) and average shear wave velocity of soil above the bedrock ($V_{S,Soil}$) were adopted as parameters to classify the sites into sub-categories because these two factors mostly affect site amplification, especially for shallow bedrock region. The 20 m of depth to bedrock was selected as the initial parameter for site classification based on the trend of site coefficients obtained from the site-specific response analyses. The sites having less than 20 m of depth to bedrock (H1 sites) are sub-divided into two site classes using 260 m/s of $V_{S,Soil}$ while the sites having greater than 20 m of depth to bedrock (H2 sites) are sub-divided into two site classes at $V_{S,Soil}$ equal to 180 m/s. The integration interval of 0.4 ~ 1.5 sec period range was adopted to calculate the long-period site coefficients ($F_v$) for reflecting the amplification characteristics of Korean geological condition. In addition, the frequency distribution of depth to bedrock reported for Korean sites was also considered in calculating the site coefficients for H2 sites to incorporate sites having greater than 30 m of depth to bedrock. The relationships between the site coefficients and rock shaking intensity were proposed and then subsequently compared with the site coefficients of similar site classes suggested in other codes.

• Journal of Korean Foot and Ankle Society
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• v.16 no.2
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• pp.87-93
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• 2012

Fractures located at the metaphyseal/diaphyseal junction at the base of the fifth metatarsal were first described by Sir Robert Jones in 1902. However, ever since, there has been disagreement and debate regarding the diagnosis, classification, pathomechanics, the incidences, and potential causes of delayed unions and nonunions, and the optimal method of treatment. It appears to be widely agreed that proximal fractures of the metaphyseal/diaphyseal region of the fifth metatarsal are prone to delayed union or even nonunion. Several classifications of proximal fifth metatarsal stress fractures have been devised. Torg et al. classified fractures involving the proximal part of the diaphysis of the fifth metatarsal into three types. The Torg classification is a good grading system that can be used to determine the type of surgery needed as well as for the prediction of prognosis. The ''plantar gap'' might add to the decision-making process for surgery and improve the prediction of patient prognosis. In addition, the new classification using 'plantar gap' might be used for classification of fifth metatarsal stress fracture. Fifth metatarsal stress fractures can be treated conservatively or surgically, and excellent results have been reported for surgery with rapid recovery in athletes. Intramedullary screw fixation has become a popular form of fixation for fifth metatarsal stress fractures. Bone grafting presents the problems of a longer recovery time and additional skin incision for harvesting. The modified tension band wiring is an useful and simple option for surgical treatment of challenging fifth metatarsal stress fractures.