• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.63-71
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• 2012

This study aimed to evaluate the accuracy of breast cancer diagnosis of digital mammography which is in the highest interest of breast imaging test, and to investigate the characteristics of breast cancer patients. For this purpose, 57 breast cancer patients who underwent breast imaging test were examined between May 2010 and June 2011. The average age of the breast cancer patients was 50.8 years old, and the most frequently occurring location was the upper outer quadrant (UOQ), accounting for 33.3%. By age, the highest occurrence rate of breast cancer was the age group of 40~49, accounting for 42.1%. As for the breast composition of the breast cancer patients, fatty breast accounted for 31.6% (18/57) and dense breast for 68.4% (39/57), indicating that nearly 70% of the breast cancer patients have dense breast. It was found that the detection rate of breast cancer was the highest (45.3%) when both microcalcification and mass are simultaneously present in the radiographic lesion of the breast imaging. In dense breast, the mass without microcalcification was lower in detection rate than fatty breast. Accordingly, the mass is the cause of raising the false negative rate in dense breast. The findings show that the false negative rate of digital mammography was 7.0% and the sensitivity 93.0%. Also, the false negative rate of dense breast was 12.8%, and the sensitivity 87.2%, indicating that the sensitivity to breast cancer in this study was higher than the dense breast of previously reported screen film mammography.

• Applied Microscopy
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• v.15 no.1
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• pp.31-58
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• 1985

The morphological study on different types of cells of reproductive organ including spermatogenesis in the adult planaria was performed to observe their cytochemical and ultrastructural characteristics. 1. Spermatogenesis The circular luminated material appears immediately inside the nuclear envelope of early spermatid and is found also in the nucleus of sperm, but typical acrosomal structures cannot be observed. Approximately ten of small-sized mitochondria occur around the nucleus in the transitional phase from primary spermatocyte to secondary spermatocyte, but in sperm a long mitochondrion is closely associated with nucleus, parellel to long axis of it. The sperm has a relatively long head connected with two tails via hollow neck. 2. Reproductive organ The penis bulb and the bursa stalk were observed. (1) Penis bulb The cells constituted penis bulb are classified into six types on the basis of ultrastructure of the cells and cytochemistry of the cytoplasmic granules. 1) A-type cells: These cells exhibiting low electron density are mainly occupied by large nucleus. These cells possess two different types of granules: highly electron-dense round granules with an average size of $0.9{\mu}m$, and electron-dense granules exhibit PAS-positive reaction. 2) B-type cells contain PAS-positive granules with the size of about $0.4{\mu}m$. They are rich in free ribosomes and mitochondria. 3) C-type cells are found to be dark cells due to high electron-density. These cells are largely occupied by large nucleus. 4) D-type cells: These cells are seen as light cells which have poorly developed cell organelles. 5) E-type tells: These cells contain a large number of glycogen granules which occupy most of cell. 6) F-type cells: These arc parietal epidermal cells surrounding the genital antrum. These cells are characterized by their finger-like shapes and the presence of a number of electron-dense, irregularly-shaped structures inside cells. The relatively large electron-lucent granules can be also found. The F-type cells possess numerous microvilli on their free surfaces. (2) Bursa stalk The cells constituted bursa stalk are classified into 3 types on the basis of cell shapes and presences of electron-dense or electron-lucent granules. 7) G-type cells with a long cytoplasmic process. They have large nuclei and poorly developed cell organelles. 8) H-type cells: These cells are characterized by the presence of a long cytoplasmic process and relatively highly electron-dense cytoplasmic profile. They have poorly developed cell organelles. 9) I-type cells contain large electron-lucent granules which exhibit negative reactions with three kinds of cytochemical staining methods used in this experiment. The fine electron-dense structures can be found inside these granules.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.1
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• pp.23-33
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• 2020

Recently, high-resolution images can be easily acquired using UAV (Unmanned Aerial Vehicle), so that it is possible to produce small area observation and spatial information at low cost. In particular, research on the generation of cover maps in crop production areas is being actively conducted for monitoring the agricultural environment. As a result of comparing classification performance by applying RF(Random Forest), SVM(Support Vector Machine) and CNN(Convolutional Neural Network), deep learning classification method has many advantages in image classification. In particular, land cover classification using satellite images has the advantage of accuracy and time of classification using satellite image data set and pre-trained parameters. However, UAV images have different characteristics such as satellite images and spatial resolution, which makes it difficult to apply them. In order to solve this problem, we conducted a study on the application of deep learning algorithms that can be used for analyzing agricultural lands where UAV data sets and small-scale composite cover exist in Korea. In this study, we applied DeepLab V3 +, FC-DenseNet (Fully Convolutional DenseNets) and FRRN-B (Full-Resolution Residual Networks), the semantic image classification of the state-of-art algorithm, to UAV data set. As a result, DeepLab V3 + and FC-DenseNet have an overall accuracy of 97% and a Kappa coefficient of 0.92, which is higher than the conventional classification. The applicability of the cover classification using UAV images of small areas is shown.

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.204-210
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• 2003

Membranoproliferative glomerulonephritis type II(MPGN II), also called dense deposit disease, was first described by Berger and Galle in 1963. The diagnosis of MPGN II is based on electron-microscopic finding of an intensely electron-dense substance which replaces the lamina densa of the glomerular basement membrane. Although the etiology and pathogenesis of MPGN II are unknown, it frequently progresses to end-stage renal failure. Typically in MPGN II, hypocomplementemia due to activation of the alternative complement pathway is present. In addition, the association of MPGN II with partial lipodystrophy and complement abnormalities is well documented. The relationship between these associated features and the patient's renal functional outcome is not clear. With respect to the therapy for MPGN II, an alternate-day prednisolone regimen was shown to be effective. Various treatment modalities, including immunosuppression with corticosteroids, cytotoxic drugs and cyclosporin A, anticoagulants and antiplatelet therapies are used, either alone or in combination, with varying degrees of success. The purpose of this paper is to present a case of MPGN II from a 7 years old girl with paroxysmal supraventricular tachycardia(PSVT).

• Korean Journal of Radiology
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• v.20 no.8
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• pp.1275-1284
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• 2019

Objective: To develop algorithms using convolutional neural networks (CNNs) for automatic segmentation of acute ischemic lesions on diffusion-weighted imaging (DWI) and compare them with conventional algorithms, including a thresholding-based segmentation. Materials and Methods: Between September 2005 and August 2015, 429 patients presenting with acute cerebral ischemia (training:validation:test set = 246:89:94) were retrospectively enrolled in this study, which was performed under Institutional Review Board approval. Ground truth segmentations for acute ischemic lesions on DWI were manually drawn under the consensus of two expert radiologists. CNN algorithms were developed using two-dimensional U-Net with squeeze-and-excitation blocks (U-Net) and a DenseNet with squeeze-and-excitation blocks (DenseNet) with squeeze-and-excitation operations for automatic segmentation of acute ischemic lesions on DWI. The CNN algorithms were compared with conventional algorithms based on DWI and the apparent diffusion coefficient (ADC) signal intensity. The performances of the algorithms were assessed using the Dice index with 5-fold cross-validation. The Dice indices were analyzed according to infarct volumes (< 10 mL, ≥ 10 mL), number of infarcts (≤ 5, 6-10, ≥ 11), and b-value of 1000 (b1000) signal intensities (< 50, 50-100, > 100), time intervals to DWI, and DWI protocols. Results: The CNN algorithms were significantly superior to conventional algorithms (p < 0.001). Dice indices for the CNN algorithms were 0.85 for U-Net and DenseNet and 0.86 for an ensemble of U-Net and DenseNet, while the indices were 0.58 for ADC-b1000 and b1000-ADC and 0.52 for the commercial ADC algorithm. The Dice indices for small and large lesions, respectively, were 0.81 and 0.88 with U-Net, 0.80 and 0.88 with DenseNet, and 0.82 and 0.89 with the ensemble of U-Net and DenseNet. The CNN algorithms showed significant differences in Dice indices according to infarct volumes (p < 0.001). Conclusion: The CNN algorithm for automatic segmentation of acute ischemic lesions on DWI achieved Dice indices greater than or equal to 0.85 and showed superior performance to conventional algorithms.

• Journal of the Optical Society of Korea
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• v.8 no.2
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• pp.55-58
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• 2004

Several internal wavelength locker schemes for 10 Gbps electro-absorption modulated laser EML) module were reviewed. 10 Gbps EML modules with simple and robust internal wavelength ockers for metro dense WDM application were successfully demonstrated. The wavelength aging ver 2000 hours was done at elevated temperature of 7$0^{\circ}C$. The average wavelength drift of 10 modules was measured to be about $\pm$ 5 pm. These modules can be successfully applied to the 0 Gbps DWDM systems with 50 ㎓ channel spacing.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1891-1894
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• 2013

• Journal of the Chungcheong Mathematical Society
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• v.10 no.1
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• pp.147-159
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• 1997

It is important to solve the large sparse linear system appeared in many application field such as $AA^Ty={\beta}$ efficiently. In solving this linear system, the sparse solver using the splitting method for the relatively dense column is experimentally better than the direct solver using the Cholesky method.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.54.2-54.2
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• 2015

Within 100 pc of the Galactic Centre the tidal field is extremely strong. We investigate the survival of star clusters of different masses in strong tidal fields. We show that dense low-mass clusters are destroyed by strong tidal fields as the tidal fields add energy to the cluster. Only massive clusters (like the Arches) can survive for more than 1-2 Myr in strong tidal fields. Therefore, in Galactic Centre environments only massive young clusters should ever be observed.

• Journal of applied mathematics & informatics
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• v.33 no.5_6
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• pp.503-515
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• 2015

In this paper the concepts of pairwise fuzzy regular Volterra spaces and pairwise fuzzy weakly regular Volterra spaces are introduced. Several characterizations of pairwise fuzzy regular Volterra spaces and pair-wise fuzzy weakly regular Volterra spaces are investigated.