• Journal of Magnetics
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• v.21 no.4
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• pp.593-598
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• 2016

In order to reduce the amount of noise component in X-ray imaging system, various reduction techniques were frequently used in the field of diagnostic imaging. Although the previous techniques -such as median, Wiener filters and Anscombe noise reduction technique - were able to reduce the noise, the edge information was still damaged. In order to cope with this problem, total variation (TV) noise reduction technique has been developed and researched. The purpose of this study was to evaluate and compare the image quality using normalized noise power spectrum (NNPS) and contrast-to-noise ratio (CNR) through simulations and experiments with respect to the above-mentioned noise reduction techniques. As a result, not only lowest NNPS value but also highest CNR values were acquired using a TV noise reduction technique. In conclusion, the results demonstrated that TV noise reduction technique is proved as the most practical method to ensure accurate denoising in X-ray imaging system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.519-522
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• 2002

Ag (silver) can be used for YBa$_2$Cu$_3$O$\_$7-$\delta$/(YBCO) coated conductor tape as the substrate on which YBCO can be deposited directly because of the chemical compatibility of Ag with YBCO. We have fabricated rolled Ag tapes with various total reduction ratios and different thicknesses. As-rolled Ag tape was recrystallized at 750$^{\circ}C$ for 30min in air and vacuum of 10$\^$-3/ torr. The orientation distribution functions (ODF) calculated from three x-ray pole figures of as-rolled and recrystallized tapes were analysed. As the total reduction ratio increased from 94 to 98%, the development of {110}texture of as-rolled Ag improved. Under the present experimental condition, maximum {110}ODF value of Ag tape was obtained for the sample with 94% total reduction ratio which was recrystallized at 750$^{\circ}C$ for 30min in vacuum of 10$\^$-3/ torr.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.639-646
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• 2022

The present experiment was conducted to assess the effect of Buttiauxella-derived phytase in finishing pigs fed corn/soybean meal diets with an increase in the calcium (Ca)/total phosphorus (P) (Ca/tP) ratio and a reduction in net energy on the growth performance and nutrient digestibility on the finishing pigs. A total of 90 crossbred ([Yorkshire × Landrace] × Duroc) finishing pigs with an average initial body weight (BW) of 56.94 ± 2.43 kg were used for an 11-week feeding trial. The pigs were randomly allotted to one of three dietary treatments (six replication/treatment and five pigs/pen) in a randomized complete block design according to their BW and gender. Dietary treatments consisted of supplementation of phytase (0.05, 0.07, and 0.1% in the control, Trt1 and Trt 2 diets, respectively) maintaining the Ca/tP ratio (1.67 : 1, 1.84 : 1, and 2.19 : 1 in control, Trt1 and Trt 2 diets, respectively) and reducing the net energy by 1% in Trt1 and Trt2 diets compared with the control diet. The results showed that dietary supplementation with phytase in the energy-reduced diet had a similar (p > 0.05) effect on the BW, average daily gain, average daily feed intake, and gain/feed ratio of the finishing pigs. Also, there were no effects (p > 0.05) of treatment matrixes on the nutrient digestibility of dry matter, nitrogen calcium, phosphorus, and gross energy. In conclusion, the increase of phytase and Ca/tP ratio and the reduction of net energy in the corn/soybean meal diet resulted in comparable growth performance and nutrient digestibility of finishing pigs relative to pigs fed the control diet.

• Computational Structural Engineering
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• v.8 no.4
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• pp.17-23
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• 1995

Based on the present FEM study for negative Poisson's-ratio UHMWPE, the following conclusions seem expected. 1) Negative Poisson's-ratio UHMWPE transfers less stresses to the subchondral or peripheral iliac bone, compared to the conventional UHMWPE with Poission's-ratio. 2) Negative Poisson's-ratio cup reduces stresses in UHMWPE cup itself as well as metal backing, and subchondral bone. 3) The reduction in periacetabular mechanical stresses would significantly reduce the rate of fatigue failure and consequently reduce the incidence of aseptic loosening of the cup due to wear or bone resorption.

• Architectural research
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• v.19 no.4
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• pp.89-94
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• 2017

In Korea, it is necessary to improve the performance of buildings with respect to the energy efficiency while improving the quality of occupants' lives through a sustainable built environment. During the design and development process, building projects must have a comprehensive, integrated perspective that seeks to reduce heating, cooling and lighting loads through climate-responsive designs. The aim of this study is to assess the optimal window-to-wall ratio of multi-rise residential units in the early design phase in Korea. The study analyzed the variation of annual heating and cooling energy load in two apartment prototype units located in Seoul city using different WWRs. The analysis was conducted using Autodesk Ecotect Analysis 2011 tool. The study found for total annual building load reductions WWR on the south and north face should be studied independently based on the room function. It also found reducing the WWR for bedrooms and windows on the northern façade resulted in reduced total annual building load.

• International Journal of Oral Biology
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• v.45 no.2
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• pp.51-57
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• 2020

Thromboelastography or rotational thromboelastometry, is being increasingly utilized in cardiac surgery of late. However, it is an indirect test and is not available in all centers. Low fibrinogen levels before and after cardiopulmonary bypass (CPB) have been described to be associated with postoperative bleeding in cardiac surgery. This study explored the usefulness of reduction ratio of the fibrinogen levels before CPB (preCPB) and after CPB (postCPB) in predicting postoperative hemorrhage. A retrospective, observational study of adult patients who underwent cardiac surgery with CPB between February 2014 and January 2016 was conducted, which included a total of 264 patients. The fibrinogen levels were measured twice, preCPB and postCPB, and the fibrinogen reduction ratio was acquired [(preCPB - postCPB)/preCPB]. Postoperative blood loss, which was defined as the blood collected from the chest drain for 12 hours following arrival at the intensive care unit, was considered severe if it was more than 1,000 mL. A multivariate analysis showed that fibrinogen reduction ratio, sex, and postCPB platelet count were significantly associated with severe postoperative bleeding. However, the pre- and postCPB fibrinogen levels were not significantly associated with severe bleeding. Furthermore, a fibrinogen reduction ratio of > 41.3% was independently associated with postoperative severe bleeding, with an odds ratio of 3.472 (1.483-8.162). These results suggest that the reduction ratio of pre- and postCPB fibrinogen levels may be utilized in predicting postoperative bleeding.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.2
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• pp.75-83
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• 2015

This study was aimed to estimate the total application cost and utilization of Turf grass VFS application through the field experiment. The experimental plots were constructed in an upland field of Iksan city within the Saemangeum watershed. Turf grass was transplanted at the down-slope edge of the pollution source area in each of the treated plots. Three rainfall events were monitored during the experiment period, and the rainfall-runoff relationships and NPS pollution reduction effects of the VFS systems were assessed. As results, the reduction ratio of runoff volume ranged 14.1~64.0 %, while the NPS pollution reduction ratio ranged 9.8~73.9 % for SS, 24.0~84.2 % for T-N, 31.6~80.9 % for T-P respectively. The total cost of VFS application was estimated by considering purchase cost of Turf grass sods and construction and maintenance costs of VFS system as well as the loss caused by giving up crop cultivation for the area needed to construct the VFS. The total cost of the VFS was estimated to be approximately \3,379,000/ha/year for the first year of application, and this cost could be decreased to \1,899,000/ha/year from the second year as the construction cost of VFS could no longer need to be counted afterwards. Apart from the NPS pollution reduction effects, the possible utilization of VFS was examined by detaching Turf grass within 40 % of VFS area for sale during spring time when the VFS systems fully covered. The benefit of selling the detached Turf grass sods was estimated as \1,260,000/ha/year, and also found that the VFS area successfully recovered by the time of the summer period. This benefit could attract farmers to adopt the VFS technique to manage agricultural NPS pollution.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.859-865
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• 2012

It is necessary to evaluate performances hitherto carried out in the management of Total Maximum Daily Loads (TMDLs) and to set up direction so that this system can be improved continuously in the future. This study was investigated load allocation achievement ratio, water quality goal achievement ratio and interrelation between water quality goal and load allocation for the first period (2004~2010). Load allocation achievement and BOD water quality goal achievement ratio were 50% and 73% in Guem River Basin, respectively. The main reason for excess of load allocation and shortfall of water quality goal were unfulfilled reduction plan and pollution sources increment. Therefore, it is necessary to develop enhanced pollution sources prediction method and make a list realizable reduction plan. 63% of the unit watershed was not interrelation between water quality goal and load allocation. The reason why water quality goal and load allocation had not correlation were water quality of upper unit watershed, increment of inflow quantity, effluent water quality of wastewater treatment plant affected the unit watershed, increment of inner productivity by algae, water quality deterioration during the specific period, river management flow, etc.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.514-519
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• 2003

The objective of this study is to document the secondary flow and the total pressure loss distribution in the contoured endwall installed linear turbine nozzle guide vane cascade passage and to propose an appropriate contraction ratio of the contoured endwall which shows the best loss reduction among the simulated cases. In this study, three different contraction ratio of contoured endwalls have been tested. This study was performed by experimental method and when the contoured endwall has the contraction ratio of 0.17 on exit height the results showed the best loss reduction.

• The Journal of Fisheries Business Administration
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• v.34 no.1
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• pp.31-44
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• 2003

The purpose of this study is to investigate empirically interaction among the financing decision, investment decision, and profitability by using 41 fisheries corporations in Korea, and to suggest implications of the empirical results for government's financial policy for fisheries corporations. Sample period is 19 years from 1982 till 2000. This analysis method employs the two stage least squares(2SLS) estimation method. From the results of regression analysis by 2SLS estimation method, the adjusted $R^2$ values were high and the overall F values indicated significant. The empirical results of this study are as follows; (1) determinant factors of capital structure model for fisheries are profitability, firm-size, fisheries investment of total asset, and business risk. As pecking order theory explains, the higher is profitability the lower is debt ratio. The larger firm-size, the higher is debt ratio. The higher is fisheries investment of total asset and business risk, the higher is debt ratio. (2) determinant factors of investment model for fisheries are the change of sales, business risk, and debt ratio. These factors have positive relation to fisheries investment of total asset (3) determinant factors of profitability model for fisheries are fisheries investment of total asset and debt ratio. These factors have negative relation to profitability. On the basis of analysis results, on the government's financial policy for fisheries corporations, I suggests that with interest rate reduction, the government should lend more funds to solve the crisis in the financial structure of the fisheries firms