• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.75-86
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• 1996

A fatigue life prediction program for multiple planar surface cracks in finite plates and T-fillet joints, based on linear elastic fracture mechanics was developed. This prediction technique include the crack coalescence, mutual interation and the stress intensity concentration effect in welded joints. Total of 44 cases were compared with lida's and Vosikovsky's experimental results and it was found that the present method was a reasonable tool for the predictioin of fatigue life.

• Journal of Astronomy and Space Sciences
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• v.7 no.1
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• pp.37-45
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• 1990

It was investigated that the effect of zonal harmonics to transfer orbit. Since parking orbit is located at low altitude, the zonal harmonics affects transfer orbit relatively high sense. So under the zonal harmonics, eccentricity and semi-major-axis which were related orbit altitude at the first hand, were investigated. As a result the zonal harmonics increases the altitude of apogee of transfer orbit. So if the zonal harmonics is considered in orbit transfer the fuel can be saved a little.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.119-129
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• 2009

According to the advent of the ubiquitous environment, not only a location based service at the outside but also a location based service at the inside was more increased socially. Accordingly, this paper proposes the efficient determination system to locate a object in frequent change of indoor environment. Proposing system in this paper introduce the NLOS identification and mitigation to resolve NLOS problem, using this way that corrects location data as RWA and KF apply to result data can improve accuracy of a object. At last we are going to compare and analyze existing typical triangulation with proposed indoor location determination system to demonstrate algorithm efficiency for proposed indoor location determination system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.120-125
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• 2009

For effective noise removal prior to video processing, noise power or noise variance of an input video sequence needs to be found exactly, but it is actually a very difficult process. This paper presents an accurate noise variance estimation algorithm based on motion compensation between two adjacent noisy pictures. Firstly, motion estimation is performed for each block in a picture, and the residue variance of the best motion-compensated block is calculated. Then, a noise variance estimate of the picture is obtained by adaptively averaging and properly scaling the variances close to the best variance. The simulation results show that the proposed noise estimation algorithm is very accurate and stable irrespective of noise level.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.2
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• pp.147-156
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• 2005

SAR interferometry (InSAR) is a technique to generate 3-Dimentional spatial information using complex data pairs observed by antennas at different locations. In case of the Two-pass differential SAR inteferometry (DInSAR), the topographic phase signature can be separated from the contribution of surface deformation in the interferometric phase. In this study, InSAR and DInSAR were implemented with ERS- l/2 tandem pair to produce DEM. The accuracy of the Resulting DEMs was analyzed.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.5
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• pp.593-598
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• 2005

The standard Kalman filter has been used to estimate the states of the target, but in the presence of a maneuver, its error is occurred and performance may be seriously degraded. To solve this problem, this paper presents a new intelligent tracking algorithm using the fuzzy Kalman filter. In this algorithm, the unknown acceleration is regarded as an additive process noise by using the fuzzy logic based on genetic algorithm(GA) method. And then, the modified filter is corrected by the new update equation method which is a fuzzy system using the relation between the filter residual and its variation. To shows the feasibility of the suggested method with only one filter, the computer simulations system are provided, this method is compared with multiple model method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.607-609
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• 2019

The split-channel two-tone OOK method proposed in this paper can improve the communication performance of IoT in fading channel environment. The frequency diversity effect can be obtained by separating the interval of the two tone signals, and a performance gain of 8 dB can be obtained in the fading channel. In addition, by using split-channel, the problem of degradation of the channel bandwidth efficiency caused by the frequency diversity technique can be prevented, thereby reducing the bandwidth efficiency by allocating the remaining frequency channels to other users.

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.38-46
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• 2008

Purpose: Growth failure is a common problem in chronic renal failure(CRF). We studied the effect of growth hormone(GH) treatment and the factors influencing growth on chronic peritoneal dialysis patients. Methods: Seventeen patients who were treated with peritoneal dialysis and GH for more than one year were enrolled. Factors influencing growth such as age, height at start of GH treatment, total Kt/Vurea, residual renal Kt/Vurea, hemoglobin, albumin, BUN, creatinine, total $CO_2$, calcium, phosphate and iPTH during GH treatment were compared between the growth group (increase in height-standard deviation score(Ht-SDS) after one year of GH treatment, n=l1) and poor growth group(no increase in Ht-SDS after one year of GH treatment, n=6). Results: The mean age at the start of dialysis was 7.7${\pm}$5.2 years and the mean age at the start of GH treatment was 8.5${\pm}$4.8 years. In the growth group, Ht-SDS at start of GH treatment was smaller(-1.72${\pm}$1.00 vs. -0.77${\pm}$0.88, P=0.048) and residual renal Kt/Vurea was better (1.54${\pm}$0.51 vs. 0.15${\pm}$0.26, P=0.02) than the poor growth group. After three years of GH treatment, Ht-SDS of the growth group was better than the poor growth group. Conclusion: GH treatment in children with peritoneal dialysis was more effective on patients who had more severe growth retardation. The reservation of residual renal function was important for improvement of effect of GH treatment. And the growth response during the first year of GH treatment may be predicted as the indicator for long-term response.

• Journal of Life Science
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• v.30 no.8
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• pp.688-694
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• 2020

In a previous study, the total phenolic content in ethanol extracts of medicinal plants that naturally grow on Jeju Island were analyzed with the extracts of Raphiolepsis indica leaf found to have the highest. The current study was carried out to evaluate the total flavonoid content, radical-scavenging activity, and the protective effect of R. indica extracts and solvent fractions on oxidative stress in HaCaT keratinocytes. More specifically, total flavonoid content and 2-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical-scavenging activity were measured to assess anti-oxidative activity, and protective effects against hydrogen peroxide (H₂O₂) were determined by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay on the HaCaT cells. Of the various fractions analyzed, the ethyl acetate extract of R. indica showed the highest total flavonoid content (149.13 mg/g extracts) and the lowest remaining ABTS. In addition, the ethyl acetate fraction was significantly more resistant against H₂O₂ than the negative control. Our results therefore suggest that an ethyl acetate fraction of R. indica protects HaCaT cells against oxidative stress and could prove useful for developing functional cosmetic materials.

• The Korean Journal of Pharmacology
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• v.17 no.1 s.28
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• pp.1-8
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• 1981

The $Na^+$-induced calcium release and the effect of sodium on the transmitochondrial calcium flux were observed in mitochondria isolated from pig ventricular myocardium by Milipore filtration technique using radioisotope $^{45}Ca$. The release of calcium from cardiac mitochondria was induced by small amount of sodium, and was promoted by increasing sodium concentration in the incubation medium. The extent of the $Na^+$-induced calcium release was much greater in the absence of extramitochondrial calcium than in the presence of calcium. At steady state of calcium binding on the mitochondrial membrane unidirectional calcium influx was inhibited by sodium and unidirectional calcium efflux was increased., From the above results, it was suggested that calcium might be released from cardiac mitochondria in exchange with sodium through the mediation of the postulated '$Na^+/Ca^{++}$ exchange' mechanism.