• Journal of radiological science and technology
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• v.31 no.2
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• pp.135-140
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• 2008

Purpose: Fatty liver is one of the most commonly found disease by abdominal ultrasonography. The status of fatty liver is classified into mild, moderate and severe degrees. The study was conducted to investigate the clinical significance of fatty liver using ultrasonography. Materials and method: Test set consisted of 2,185 patients who visited D healthcare center in Daejeon to receive an abdominal ultrasonic test from January to December 2007. Out of the 2185 patients, 524 patients was diagnosed as fatty liver (290 male and 234 female patients). They were divided into three groups, group I for mild degree. II for moderate degree, and III for severe degree, depending on the echo of liver parenchyma, the sound attenuation, and the visibility of intrahepatic blood vessels and diaphragm. Then the correlation of obesity indices, liver function tests and metabolic syndrome was analyzed for males and females separately. Results : As for the degree of fatty liver, 350 cases (66.8%) were classified as group I, 153 cases (29.2%) as group II, and 21 cases (4.1%) as group III. In addition, severe degree of fatty liver was more frequently found in males than in females. The mean ages of three groups for males were 46.1, 44.5, and 39.1, and those for females were 48.8, 50.2, 52.4, respectively. Males with lower mean ages have severely of fatty liver for both males and females. Conclusion: The results in this study show that the classification into three degrees of fatty liver in ultrasonography practice is helpful to treat and observe the progress of fatty liver. In addition, careful examination is required to measure the severity of fatty liver as well as detection of it. A standardized method to classify the degree of fatty liver is also needed for more objective measurement.

• Journal of the Korean Society of Costume
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• v.18
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• pp.321-337
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• 1992

Fashions are constantly subject to change, so that forecasting trends in fashion is very difficult and the forecasting is very important. The reason is that forecasting is identifying a hot trend for the next days' business and projecting the future. The purpose of this study is to suggest the realistic forecasting theory identify fashion trends at present, further forecast fashion trends to 1995. For this study, historical models (th historical resurrection model, the historical continuity model) and the art movement model among the behavioral science models which was suggested in 1986 by Geoge B.Sproles were selected. According to this study, was exhibited. This curve was resulted from relation between 1980s fashion trends and the behavioral science models of fashion. Fashion trends to 1995 through will be followings; 1. Body Conscious look as one of the characteristics of modern fashion will bi continued throughout 1990s' fashion trends. 2. The attraction of Mini style was started from the middle of 1980s, recently gets near micro mini and super shouts, These are representative of the historical continuity model. 3. Mini look as revivals of '60s in early 1990s fashion trends. This phenomenon identifies that "Fashion is repetition" 4. When Mini look and super shorts reach, will not progress any more. In this time, will bi seen transfer of style be using classic style. Tat is modern classic will be appeared. also this condition is same from late 1960s to early 1970s. In view of the historical base, the action of the varieted pants will be prominent. 5. Fashion trends which passed through this process will transfer from young look to elegant look. In this time, designers will retrospect '30s and '50s fashion trends, and then will design modern feminine look. 6. Ethnic look, the fashion trend after that condition will be accelated feminine look. This look with the feminine look will reveal rich, colorful, elegance feminine image. 7. In 1980s, activity and function in clothes were demanded. The clothes which are considered these condition will be demanded continuously. 8. The variety of fashion will appear as mixmode and new coordinate look in a clothes simultaneously in fashion of '90s. And these looks will creat mixed beauty. 9. Pop art, op art, graphic art will be not only development of textile but also movement of fashion soul in 1990s. The fashion behavior will be continuously scientificated.

• Progress in Medical Physics
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• v.11 no.1
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• pp.1-18
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• 2000

For wedged photon beams, the variation of the wedge factor with field size was reported by several authors. However, until now such variation with field size had not been explained quantitatively. Therefore, the variation of the wedge factor was investigated by measuring outputs with field sizes increasing from 4 cm $\times$ 4 cm to 25 cm $\times$ 25 cm for open and wedged 6 and 10MV X-ray beams. The relative outputs for wedged fields to 10 cm $\times$ 10 cm have been obtained. The results show the Increase of the wedge factor caused by the change in fluence of high energy Photon beam with field size, up to 8.0% for KD77-6MV X-ray beam. This increase could be explained as a linear function of the irradiated wedge volume except small field size up to about 10 cm. In the cases of the narrow rectangular beam parallel to the wedge direction, the wedge factor decreases slightly with increasing field size up to about 10-15 cm due to a relatively reduced photon fluence from the change of the wedge thickness. We could explain the causes of a wedge factor variation with field size as the fluences of primary photon passed throughout the wedge, contributing to the dose at the central beam axis and that the fluences were affected by the gradient of the wedge with the change of field size. For clinical use, the formula developed to describe the wedge factor variation with field size has been corrected.

• Progress in Medical Physics
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• v.28 no.4
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• pp.135-143
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• 2017

Chemical Exchange Saturation Transfer (CEST) imaging is a method to detect solutes based on the chemical exchange of mobile protons with water. The solute protons exchange with three different patterns, which are fast, slow, and intermediate rates. The CEST contrast can be obtained from the exchangeable protons, which are hydroxyl protons, amine protons, and amide protons. The CEST MR imaging is useful to evaluate tumors, strokes, and other diseases. The purpose of this study is to review the mathematical model for CEST imaging and for measurement of the chemical exchange rate, and to measure the chemical exchange rate using a 3T MRI system on several amino acids. We reviewed the mathematical models for the proton exchange. Several physical models are proposed to demonstrate a two-pool, three-pool, and four-pool models. The CEST signals are also evaluated by taking account of the exchange rate, pH and the saturation efficiency. Although researchers have used most commonly in the calculation of CEST asymmetry, a quantitative analysis is also developed by using Lorentzian fitting. The chemical exchange rate was measured in the phantoms made of asparagine (Asn), glutamate (Glu), ${\gamma}-aminobutyric$ acid (GABA), glycine (Gly), and myoinositol (MI). The experiment was performed at a 3T human MRI system with three different acidity conditions (pH 5.6, 6.2, and 7.4) at a concentration of 50 mM. To identify the chemical exchange rate, the "lsqcurvefit" built-in function in MATLAB was used to fit the pseudo-first exchange rate model. The pseudo-first exchange rate of Asn and Gly was increased with decreasing acidity. In the case of GABA, the largest result was observed at pH 6.2. For Glu, the results at pH 5.6 and 6.2 did not show a significant difference, and the results at pH 7.4 were almost zero. For MI, there was no significant difference at pH 5.6 or 7.4, however, the results at pH 6.2 were smaller than at the other pH values. For the experiment at 3T, we were only able to apply 1 s as the maximum saturation duration due to the limitations of the MRI system. The measurement of the chemical exchange rate was limited in a clinical 3T MRI system because of a hardware limitation.

• Progress in Medical Physics
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• v.19 no.4
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• pp.291-297
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• 2008

The purpose of this study is to optimize a parallel-hole collimator for small gamma camera having the pixellated crystal array and evaluate the effect of crystal-collimator misalignment on the image quality using a simulation tool GATE (Geant4 Application for Tomographic Emission). The spatial resolution and sensitivity were measured for the various size of hexagonal-hole and matched square-hole collimators with a Tc-99m point source and the uniformity of flood image was estimated as a function of the angle between crystal array and collimator by misalignment. The results showed that the spatial resolution and sensitivity were greatly improved by using the matched collimator and the uniformity was reduced by crystal-collimator misalignment.

• Progress in Medical Physics
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• v.19 no.4
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• pp.247-255
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• 2008

A coded aperture camera has been developed to improve the signal-to-noise ratio (SNR) while keeping the spatial resolution of a pinhole gamma camera. The purpose of this study was to optimize a coded aperture camera and to evaluate its possibility for thyroid imaging by Monte Carlo simulation. A clinical gamma camera, a pinhole collimator with 1.0 mm hole diameter, and a $79{\times}79$ modified uniformly redundant array (MURA) mask were designed using GATE (Geant4 Application for Tomographic Emission). The penetration ratio, spatial resolution, integral uniformity and signal-to-noise ratio (SNR) were simulated and evaluated as a function of the mask thickness. The spatial resolution of the coded aperture camera was consistent with the various mask thickness, SNR showed a maximum value at 1.2 mm mask thickness and integral uniformity was improved by increasing mask thickness. Compare to the pinhole gamma camera, the coded aperture camera showed improved SNR by a factor of 30 while keeping almost the same spatial resolution. In this simulation study, the results indicated that high spatial resolution and ultra-high SNR of the thyroid imaging are feasible using a coded aperture camera.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.644-652
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• 2018

This paper describes the conceptual design of a customized gripper for the assembly process of IT products, which has a relatively short and regular product replacement cycle. The grippers that are used in the manufacturing field are mostly composed of one to two degrees of freedom and they can only handle one object, not multiple ones. Cost is also an important factor. If it were possible to develop a gripper suitable for the assembly process quickly and easily, some of the difficulties involved in its automation caused by the frequent changes of product and process could be solved. The assembly process utilized for this research is defined and described as the procedure and method of the process analysis due to the confidentiality of the manufacturer. We used an axiomatic design to derive the functional requirements and design parameters of the gripper used for the tablet PC assembly process. We proposed a design method for the conceptual design of the gripper by determining these parameters. For the feasibility study, a specific process was selected and the progress of the gripper design was described as an example. Although there have been studies on the design guidelines for grippers, their considerations are too general and their degree of freedom is too high. This paper defines the function of the gripper based on the assembly process of the IT products, which allows their production to be streamlined and automated. In this research, we attempted to produce a design that reflects the assembly process, not just one that enables objects to be held.

• Progress in Superconductivity
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• v.6 no.1
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• pp.79-83
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• 2004

We fabricated Bi-2223/Ag superconductor tape with 55 filaments and estimated the magnetic field dependence of critical current (I$_{c}$) and index n (n) up to 30 T at 4.2 K. The I$_{c}$ and n were characterized as a function of external magnetic field parallel to the tape surface on increasing and decreasing field, using a 35 T hybrid magnet. The $I_{c}$ was estimated to be 325 A, and n was 32, 22, and 26 in the electric field range of $0.1 ∼1\mu$V/cm, 1∼10 $\mu$V/cm, and 0.1∼10 $\mu$V/cm, respectively, under self-field at 4.2 K. It was observed that $I_{c}$ was dependent on magnitude of magnetic field and it decreased exponentially as the field increased; in a parallel and increasing field, It was 128 A at 30 T which is approximately 40% of critical current in self-field. In addition, the $I_{c}$ was higher on decreasing field than that on increasing one. On the other hand, n did not significantly depend on field strength up to 30 T, nor varied on whether increasing or decreasing field; n value in 0.1∼1 $\mu$V/cm was 23.0$\pm$5.2 and 27.8$\pm$8.0 on increasing and decreasing field, respectively. The n value on decreasing magnetic field was slightly higher than that on increasing field. This hysteretic behavior of n was similar to that of$ I_{c}$, which is related to the trapped flux at the grain boundary.ary.

• Progress in Medical Physics
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• v.19 no.3
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• pp.178-185
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• 2008

Living donor liver transplantation is increasingly performed as an alternative to cadaveric transplantation. Preoperative screening of the donor candidates is very important. The quality, size, and vascular and biliary anatomy of the liver are best assessed with magnetic resonance (MR) imaging or computed tomography (CT). In particular, the volume of the potential graft must be measured to ensure sufficient liver function after surgery. Preoperative liver segmentation has proved useful for measuring the graft volume before living donor liver transplantations in previous studies. In these studies, the liver segments were manually delineated on each image section. The delineated areas were multiplied by the section thickness to obtain volumes and summed to obtain the total volume of the liver segments. This process is tedious and time consuming. To compensate for this problem, automatic segmentation techniques have been proposed with multiplanar CT images. These methods involve the use of sequences of thresholding, morphologic operations (ie, mathematic operations, such as image dilation, erosion, opening, and closing, that are based on shape), and 3D region growing methods. These techniques are complex but require a few computation times. We made a phantom for volume measurement with pig and evaluated actual volume of spleen and liver of phantom. The results represent that our semiautomatic volume measurement algorithm shows a good accuracy and repeatability with actual volume of phantom and possibility for clinical use to assist physician as a measuring tool.

• Spatial Information Research
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• v.21 no.3
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• pp.21-30
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• 2013

Recently, interest of submarine mineral resources has been increasing from the depletion of land resources around the world and many countries are involving in submarine mineral resource exploration work. South Korea is also in progress of mineral exploration and relevant study to ensure the submarine mineral resources from around the Korean Peninsula. As a result, the submarine mineral resource exploration data have been increasing annually. A database and 2D GIS-based system have been constructed for the management of the data. However, submarine mineral resource exploration data is explored and created on the sea-bed. Consequently, the visual confirmation of the water levels and marine landform is important for high dimension analysis. Therefore, the major aims of this study are to collect marine landform data from around the Korean Peninsula and to develop 3 dimension GIS based system that is linked to the submarine mineral resource exploration data. In detail, marine landform data were acquired for the Korean Peninsula and they were interpolated into raster file format. The raster file was then processed to be easily used and was entered into an Oracle database. Based on this database, 3D expression and overlap function between marine landform data and submarine mineral resource exploration data were designed using ArcScene offered by the ESRI. After design, 3D GIS based expression system was developed. Confirmations of locations and changes in the submarine mineral resource exploration data based on 3D GIS are enabled to support the efficient application of the proposed system. It is expected that this system will be highly useful for estimating the reserves of mineral resources and for providing valuable information for economic evaluations.