• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.289-290
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• 1998

Purpose To investigate the difference of total activation in visual area, motor area, and cerebellum according to the stimulation paradigm. Materials and Methods Functional MR imaging was performed in 5 healthy volunteers with visual and motor activity using EPI technique. LED and Checker-Board stimulation were performed for visual activity. Thumb motion and Finger tapping were performed for motor and cerebellum activity. Time course data was obtained by calculating the total activation which was defined as the number of activated pixels x averaged pixel intensity. Results In the case of visual activity with LED stimulation, we found increased total activity of more than 100% compared with Checker-Board stimulation. In the case of motor area and cerebellum with Finger tapping stimulation, we found increased total activity of more than 100% and 150%, respectively compared with Thumb motion stimulation.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.6
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• pp.531-538
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• 2020

Purpose: Our aim was the longitudinal assessment of cyst size in fetuses with biliary cystic malformation (BCM) to explore its etiology and the possibility of antenatal differentiation between biliary atresia (BA) and congenital biliary dilatation (CBD). Methods: We conducted a retrospective review of all patients diagnosed antenatally with BCM from 1994 to 2014 at our institutions. Results: The study cohort comprised of three patients with BA and six with CBD. There were no significant differences in the gestational age and cyst size at the first detection of BCM between the two groups. In fetuses with CBD, the cyst size steadily increased as the gestational age advanced, while it fluctuated around 1.5 cm and remained below 2.1 cm in those with BA. However, the ratio of cystic area to fetal trunk area was approximately constant due to linear fetal growth in fetuses with CBD. Conclusion: Fetuses with BCM <2.1 cm in the late gestation period were more likely to have BA than CBD. Our observation of cyst enlargement with advancing gestational age in the CBD group was attributed solely to fetal growth. Biliary dilatation in fetuses with CBD and BA might be completed at the onset of BCM.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.21-27
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• 1997

Total laryngectomy has become an usual treatment for any advanced carcinoma of the laynx, but most patients who have undergone total laryngectomy have shown permanant disability in voice production. I compared the first three formant frequencies estimated from MRI to those measured directly from speech data of the T-E patients and the normal. It was to estimate the accuracy of MRI and to compare the vocal tract shape of the normal to T-E patients. The obtained results were as follows : 1. The middle sagittle section of the MRI represents vocal tract well during pnonation. The vocal tract shape of the T-E shunt patients are lack of pharyngeal space and superior space of the glottis. 2. The length of the normal subject's vocal tract is 17 cm. For the T-E shunt patients, the length from lip to shunt opening is 17.5 cm in case 1, and 18.5 cm in case 2. That of the true resonante chamber is 13 cm and 13.5 cm for each case respectively. 3. T-E shunt patients phonated strained voice. The intensity of the higher formant frequency decreased especially in /o/, /u/. 4. The vocal tract is shortened during the phonation by T-E shunt patients. In case of /e/ and /i/, front cavities are constricted while back cavities are shortened. 5. The pseudoglottis of the T-E shunt patients is located at $14{\sim}15\;cm$ below from lips.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.3
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• pp.217-223
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• 2014

With precise sensor position, attitude element, and imaging resolution, a simulated geospatial image can be generated. In this study, a satellite image is simulated using SPOT ortho-image and global elevation data, and the geometric similarity between original and simulated images is analyzed. Using a SPOT panchromatic image and high-density elevation data from a 1/5K digital topographic map data an ortho-image with 10-meter resolution was produced. The simulated image was then generated by exterior orientation parameters and global elevation data (SRTM1, GDEM2). Experimental results showed that (1) the agreement of the image simulation between pixel location from the SRTM1/GDEM2 and high-resolution elevation data is above 99% within one pixel; (2) SRTM1 is closer than GDEM2 to high-resolution elevation data; (3) the location of error occurrence is caused by the elevation difference of topographical objects between high-density elevation data generated from the Digital Terrain Model (DTM) and Digital Surface Model (DSM)-based global elevation data. Error occurrences were typically found at river boundaries, in urban areas, and in forests. In conclusion, this study showed that global elevation data are of practical use in generating simulated images with 10-meter resolution.

• Journal of Korea Foundry Society
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• v.15 no.5
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• pp.483-493
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• 1995

The microstructural changes during semi-solid state processing of hypereutectic Al-Si alloy has been investigated in the present study. Stirring of semi-solid slurry results in the morphological changes of the primary Si particles, i.e. from angular rod shape to near-spherical shape. Besides the spherodization of primary Si particles, the average particle size increases, especially, at much higher rate in the final stage than that in the early stage of stirring. Various microstructure characterization techniques, such as anisotropic etching, SEM imaging and ECP analysis, reveal that the spherodization of primary Si particles occurs by the combinations of the mechanisms of coalescence, fracture, and wear of the individual particles. Isothermal shearing of hypereutectic Al-Si at $580^{\circ}C$ shows that spherical ${\alpha}-Al$ particles are formed by the dissociation of Al-Si eutectic structure at the early stage of isothermal shearing. The spherical ${\alpha}-Al$ particles gradually grow by the mechanisms of Ostwald ripening and coalescence of the particles.

• Journal of Gastric Cancer
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• v.14 no.1
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• pp.1-6
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• 2014

Aerobic glycolysis has been the most important hypothesis in cancer metabolism. It seems to be related to increased bioenergetic and biosynthetic needs in rapidly proliferating cancer cells. To this end, F-18 fluorodeoxyglucose (FDG), a glucose analog, became widely popular for the detection of malignancies combined with positron emission tomography/computed tomography (PET/CT). Although the potential roles of FDG PET/CT in primary tumor detection are not fully established, it seems to have a limited sensitivity in detecting early gastric cancer and mainly signet ring or non-solid types of advanced gastric cancer. In evaluating lymph node metastases, the location of lymph nodes and the degree of FDG uptake in primary tumors appear to be important factors affecting the diagnostic accuracy of PET/CT. In spite of the limited sensitivity, the high specificity of PET/CT for lymph node metastases may play an important role in changing the extent of lymphadenectomy or reducing futile laparotomies. For peritoneal metastases, PET/CT seems to have a poorer sensitivity but a better specificity than CT. The roles of PET/CT in the evaluation of other distant metastases are yet to be known. Studies including primary tumors with low FDG uptake or peritoneal recurrence seem suffer from poorer diagnostic performance for the detection of recurrent gastric cancer. There are only a few reports using FDG PET/CT to predict response to neoadjuvant or adjuvant chemotherapy. A complete metabolic response seems to be predictive of more favorable prognosis.

• Korean Journal of Optics and Photonics
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• v.22 no.2
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• pp.72-76
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• 2011

We demonstrate a k-domain linearization using a fiber Bragg grating (FBG) array for Fourier domain optical coherence tomography based on a wavelength swept laser. The k-domain linearization is carried out with an interpolation method using a FBG array with five FBGs. The measured signal-to-noise ratio from the point spread function after k-domain linearization is 12 dB improved over that of without k-domain linearization at the 1 mm depth of the sample. Clear OCT imaging of the slide glass with k-domain linearization could be obtained.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.6
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• pp.413-421
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• 2015

Regularized Blind Deconvolution is a problem applicable in degraded images in order to bring the original image out of blur. Multichannel blind Deconvolution considered as an optimization problem. Each step in the optimization is considered as variable splitting problem using an algorithm called Alternating Minimization Algorithm. Each Step in the Variable splitting undergoes Augmented Lagrangian method (ALM) / Bregman Iterative method. Regularization is used where an ill posed problem converted into a well posed problem. Two well known regularizers are Tikhonov class and Total Variation (TV) / L2 model. TV can be isotropic and anisotropic, where isotropic for L2 norm and anisotropic for L1 norm. Based on many probabilistic model and Fourier Transforms Image deblurring can be solved. Here in this paper to improve the performance, we have used an adaptive regularization filtering and isotropic TV model Lp norm. Image deblurring is applicable in the areas such as medical image sensing, astrophotography, traffic signal monitoring, remote sensors, case investigation and even images that are taken using a digital camera / mobile cameras.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.95-99
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• 2011

$CaTi_{1-x}Fe_xO_3(0{\leq}x{\leq}0.4)$ solid solution photocatalysts were synthesized by iron doping during the conventional solid state reaction at $1100^{\circ}C$ for 5 h and characterized by ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction, morphological analysis. We found that $CaTi_{1-x}Fe_xO_3$ samples not only absorb UV but also the visible light photons. This is because the Fe substitution at Ti-site in $CaTi_{1-x}Fe_xO_3$ lattice induces the band transition from Fe3d to the Fe3d + Ti3d hybrid orbital. The photocatalytic activity of Fe doped $CaTiO_3$ samples for hydrogen production under UV light irradiation decreased with the increase in the Fe concentration. There exists an optimized concentration of iron in $CaTiO_3$, which yields a maximum photocatalytic activity under visible light ($\lambda\geq420nm$) photons.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.45.2-45.2
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• 2014

We carry out the first survey for globular clusters (GCs) of three galaxies in cosmic voids using Hubble Space Telescope (HST) Advanced Camera for Survey archival F606W and F814W images. While all sample galaxies are classified as early-type galaxies based on ground-based imaging, the high resolution HST images reveal that they are actually spiral galaxies. We identify the point sources with red colors typical for GCs as GC candidates in the color-magnitude diagrams. As a result, we find a significant number of GC candidates. The spatial and radial distribution of GCs show central concentration on each galaxy region. Their mean colors are similar to that of the Milky Way and M31 GCs. The void GCs are somewhat bluer by, and than cluster and field GCs in early-type galaxies with similar luminosity to our samples, but the discrepancy is not significant. We also estimate the specific frequencies of GCs in these galaxies and the values are consistent with those in field and cluster galaxies with similar luminosity. From these results, we suggest that the formation process of void GCs is similar to that of GCs in other environments. The further implications will be discussed.