• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.1
• /
• pp.41-48
• /
• 2022

This paper presents the unified Bayesian Tikhonov regularization method as a solution to total variation regularization. The integrated method presents a formula for obtaining the regularization parameter by transforming the total variation term into a weighted Tikhonov regularization term. It repeats until the reconstructed image converges to obtain a regularization parameter and a new weighting factor based on it. The experimental results show the effectiveness of the proposed method for the image restoration problem.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.13 no.1
• /
• pp.877-888
• /
• 2021

The water entry behaviors of projectiles with different cone-headed angles were studied numerically, experimentally and theoretically, mainly focusing on the hydrodynamic impact in the initial stage. Based on MMALE algorithm, it was proposed a formula of impact deceleration, which relied on the initial entry velocity and cone-headed angle. Meanwhile, in order to verify the validity of the simulation model, experiments using accelerometer and high-speed camera were carried out, and their results were in a good agreement with simulation results. Also, theoretical calculation results of cavity diameter were compared with experiments and simulation results. It was observed that the simulation method had a good reliability, which would make forecast on impact deceleration in an engineering project.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.8 no.1
• /
• pp.1-9
• /
• 1979

Heat transfer characteristics of an annular heat pipe is investigated theoretically and experimentally. An annular heat pipe transports maximum heat which is found to be a cubic polynomial function of the thickness of annulus when the annulus becomes large, maximum heat transfer rate Is limited by boiling criterion. The limit decreases inversely proportional to the thickuess of annulus. Theoretical formula for thermal resistance of annular heat pipe Is proposed. Experimental results on the maximum heat transfer rate satisfactorily agree with theory. Measured thermal resistance is found to be lower than the predicted results as the thickness of annulus becomes large.

• Journal of the Korean Society for Precision Engineering
• /
• v.11 no.6
• /
• pp.12-19
• /
• 1994

This paper deals with the bending fatigue strength of SNC815 carburized spur gears. The test gears are heat-treated by two different treatments. One is the direct quenching after car-burization. The other is treated by reheating and quenching. The fatigue test at a constant stress amplitude is performed by using an electrohydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. The fatigue strength of direct quenched gears is higher than that of reheated quenched gears. The fatigue strength is estimated from the hardness and the residual stress by using the experimental formula proposed by Tobe and Inoue. The estimated strength is close to the test results, and the validty of the formular is confirmed.

• Journal of Ocean Engineering and Technology
• /
• v.37 no.6
• /
• pp.256-265
• /
• 2023

Many numerical methods have been developed since 1961, but unresolved issues remain. This study developed a numerical method to address these issues and determine the coefficients and properties of rotational waves with a shear current in a finite water depth. The number of unknown constants was reduced significantly by introducing a wavelength-independent coordinate system. The reference depth was calculated independently using the shooting method. Therefore, there was no need for partial derivatives with respect to the wavelength and the reference depth, which simplified the numerical formulation. This method had less than half of the unknown constants of the other method because Newton's method only determines the coefficients. The breaking limit was calculated for verification, and the result agreed with the Miche formula. The water particle velocities were calculated, and the results were consistent with the experimental data. Dispersion relations were calculated, and the results are consistent with other numerical findings. The convergence of this method was examined. Although the required series order was reduced significantly, the total error was smaller, with a faster convergence speed.

• Journal of Nutrition and Health
• /
• v.31 no.8
• /
• pp.1295-1306
• /
• 1998

Recent research indicates that the n-3 fatty acid , docosahexaenoic acid(22 : 6n 3, DHA) plays an essential role in infant brain development . DHA is highly concentrated in brain and retinal tissues and accumulates during late fetal and early neonatal life. Diets deficient in DHA are associated with reduced levels of DHA in brain and retinal tissues. The purpose of this study is to investigate the long term effects of DHA supplementation on the growth and mental development of full-term infants. THirty four healty infants were recruited from those who were delivered at Kyung Hee Medical Center. The experimental groups were the breast milk+DHA(-) group who were fed human milk for 20 weeks after birth and thereafter were fed placebo formula for 28 weeks, the breast milk+DHA(+) group who were fed human milk for 20 weeks after birth and thereafter were fed DHA supplemented formula for 28 weeks, DHA(-) group who were fed placebo formula for 48 weeks, and DHA(+) group who were fed DHA supplemented formula for 48 weeks. The daily average intake of DHA for the breast milk+DHA(-) , breast milk+DHA(+), DHA(-) and DHA(+) groups were 39.1mg, 89.9mg, 17.7mg, and 160.224mg, respectively. The results showed that measurements of infant weight, length, head, and chest circumferncewere all in normal range and they were not influenced by the DHA supplements in their diets. There was a significant correlation between dietary DHA intake and erythrocyte DHA level. The results of flash visual evoke potential (VEP) test were not correlated with eerythrocyte DHA and dietary DHA levels at 48 weeks of age. No differences were found in Bayley mental and Psychomotor Development lndex scores among the four experimental groups at 48 weeks of age. Unlike the short-term effects there was no long-term effect of relatively small amounts of dietary DHA supplements on the scores for flash VEP and Bayley test, even thour호 there was an elevated DHA supplements on the scores for flash VEP and Bayley test, even through there was an elevated DHA content in the infants erythrocytes.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.24 no.2
• /
• pp.83-93
• /
• 1988

Recent Experimental results show that the J integral can be effectively used to obtain a valid parameter for predicting plane strain and plane stress fracture. However, only a few research results have been reported for the effect of thickness where the plane strain state can not be assumed. A purpose of this study is to find the behavior of fracture touhness and tearing modulus varing the specimen thickness. The type of specimen in the present study is compact tension (CT). The thicknesses of the low carbon steel specimens that are used in the experiments are 5, 10, 15, 20 and 25mm. The measurement of crack length is taken by optical measurements method. From the study, the followings are found; 1) The fracture toughness and the tearing modulus which are obtained by using Yoon's and Simpson's formula show more conservative than that by using Rice's and Merkel's. 2) The fracture toughness is increase in specimen thickness which is reached 15mm. Beyond this thickness the fracture toughness is decreased in specimen thickness. 3) In the case of CT specimen with the thickness ranging from 5 to 25mm, the tearing modulus which is applied the same J integral equation is almost constant. 4) By using Yoon's formula, the correlation of the plane slress fracture toughness J sub(C) with specimen thickness B is expressed as the following formula. J sub(C)/J sub(IC)=1.7-15.1(B/W)+112.9(B/W) super(2) -301.3(B/W) super(3) +260.6(B/W) super(4)

• Clinical and Experimental Pediatrics
• /
• v.48 no.6
• /
• pp.614-618
• /
• 2005

Purpose : Cystatin C has been proposed for the assessment of glomerular filtration rate, being more accurate than creatinine determination. We measured serum cystatin C concentrations in the pediatric population, and analysed the correlation between cystatin C and glomerular filtration rate. Methods : Cystatin C and creatinine were measured by the particle enhanced nephelometric immunoassay and Jaffé method, respectively, in 276 children and adolescents without evidence of kidney disease. The glomerular filtration rate was estimated by Schwartz's formula. Results : The mean serum cystatin C concentration was significantly higher in infants under the age of 12 months than in older population. There was a negative correlation between cystatin C and age under 12 months, but not a significant change of cystatin C with age in children older than 12 months. For children older than 12 months, the reference range of cystatin C was 0.46-1.05 mg/L. On the other hand, there was a positive correlation between creatinine and age in the whole population. We also observed a positive correlation between estimated glomerular filtration rate and 1/cystatin C. Conclusion : The measurement of cystatin C is more practical than creatinine for estimating glomerular filtration rate in the pediatric population.

• Clinical and Experimental Pediatrics
• /
• v.52 no.1
• /
• pp.28-35
• /
• 2009

Purpose : We compared body growth, blood cell counts, and chemistry among infants receiving soy-based formula (SF), breast milk (BM), and casein-based formula (CF). Methods : Full-term neonates delivered at our hospital from June 2001 to August 2003 were recruited and divided into 3 feeding groups (BM=20, SF=19, CF=12 ) according to the parents wishes. Breast feeding or artificial formulae were given during the initial 3 months of age; thereafter, weaning foods were added freely. Height, weight, head circumference, skin-fold thickness, and mid-arm circumference were measured at birth and 1, 2, 4, 5, 12, and 36 months of age. Cell counts and blood chemistry were analyzed at 5, 12, and 36 months of age. Result : At 5 months of age, body weight was the lowest in the SF group; the height was similar among all groups. Thereafter, there were no differences in height or weight among the groups until 36 months of age. Hemoglobin was the lowest in the BM group at 5 and 12 months of age (P< 0.05 ). At 5 months of age, serum cholesterol, BUN, phosphates, and K+ were significantly lower in the SF group; thereafter, all chemical parameters were similar until 36 months of age. Conclusion : Infants fed with SF showed normal growth during the first 3 years of life as compared to infants fed with BM and CF. Low values of serum phosphates and K+ at 5 months of age in the SF group, despite the high mineral content, suggest that further investigation is needed for effective mineral absorption.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06a
• /
• pp.91-98
• /
• 2006

The purpose of this study is to investigate the opacity and printing strength of MG paper overlaid plywood. The printing strength of ink on MG paper can be evaluated effectively by a formula $E^{*2}=[(L^{*})^{2}+(a^{*})^{2}+(b^{*})^{2}]^{1/2}$ that we proposed. Higher E value indicates good printing strength of ink-on-paper. We also assess the real color of translucent printed MG paper with a formula CIE ${\bigtriangleup}E^{*}$ (color difference between a pile of same paper to be opaque and fancy paper laminated board). In addition, the color difference on paper surface caused by the color of wood-based board (bottom) can be evaluated by a formula of Pc. No. Generally, an acceptable appearance quality of fancy boards is ${\bigtriangleup}E^{*}$ <2.0 and small Pc.No. value. The experimental results showed that Japan-made MG papers -J1, J2 and J3 have better printing strength and gloss than that of Taiwan-made paper (T1). The reason for this was that Taiwan-made paper has poor printing strength and low gloss, which might be correlated to the fiber compositions in paper. Higher printing strength can be seen for short fiber containing handsheets when comparing to that of handsheets. Nonetheless, low-freeness sheets gives better printing strength than that of high-freeness sheets. High-opacity MG paper gives good opacifying effect to the fancy paper laminated wood-based boards. Comparing the surface color of 2 kinds of fancy paper laminated boards, paperboard T1 laminated with high-opacity fancy paper showed slight color difference. The same results can be seen for $??g/m^{2}$ handsheets. Higher-opacity Acacia and Eucalyptus bleached sulfate pulps (short fiber) gives higher opacifying effect on the plywood when comparing to Northan pine and Radiata pine sulfate pulps(long fiber). The former ones also showed small color differences when comparing the color differences between the color of fancy paper and laminated paper board. Additionally, the color of bottom plywood can't be shown through for the high-opacify surface paper adhered to. Besides, the PC No of the base paper laminated board is small as well. Apparently, we can add colorants to the binders for the manufscture of various handsheets ($30g/m^{2}$) with various pulp mix ratios to increase the opacity of paperboards to certain extents. When we using yellow and brown binders in paper laminated board, the color difference between Acacia and Eucalyptus handsheets overlaid boards decreasing to 2.0 (acceptable ${\bigtriangleup}E^{*}$ <2.0, hard to discern), but not much improvement for Northern and Radiata pines. Definitely, show-through defects can be discernible for lower opacity papers. In general, admirable printing strength of fancy paper by which glued to plywood can be made with high-opacity paper and colored binders techniques.