• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.39-46
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• 2010

Purpose: To assess the reliability for measuring the back vertex power of soft contact lenses by dry blotting and wet cell method using an auto-lensmeter. Methods: The soft contact lenses used for measurement were 5 types that were distributed in Korea, and 4 back vertex powers (-1.50D, -3.00D, -6.00D, -9.00D) were used. and repeatability and reproducibility were evaluated by measuring them with an auto-lensmeter by two examiners. Results: Measured powers by dry blotting method were ranged in mean differences from 0.03D to 0.18D for overall lenses, 0.10D to 0.18D for silicone hydrogel lenses, 0.03D to 0.08D for hydrogel lenses. The mean differences between two examiners were less than 0.10D, and the inter-examiner reproducibility was good for dry blotting method. The mean difference between powers determined by wet cell method were 0.09D to 0.69D, the mean differences between two examiners were 0.02D to 0.59D. The reliability of measurements and inter-examiner reproducibility were less than dry blotting method. Conclusions: The reliability of measurements for all materials was better in dry blotting than wet cell method, the re liability of measurements for silicone hydrogel lenses was low in both methods. In clinical practical which requires quick checking of back vertex power using an auto-lensmeter. dry blotting method is thought to be more efficient than wet cell one.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.57-62
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• 2009

Purpose: Brain SPECT study is more sensitive to motion than other studies. Especially, when applying 1-day subtraction method for Diamox SPECT, it needs shorter study time in order to prevent reexamination. We were required to have new study condition and analysing method on dual detector system because triple head camera in Seoul National University Hospital is to be disposed. So we have tried to increase image quality and make the dual and triple head to have equivalent study time by using a new analysing program. Materials and Methods: Using IEC phantom, we estimated contrast, SNR and FWHM. In Hoffman 3D brain phantom which is similar with real brain, we were on the supposition that 5% of injected doses were distributed in brain tissue. To compare with existing FBP method, we used fan-beam collimator. And we applied 15 sec, 25 sec/frame for each SEPCT studies using LEHR and LEUHR. We used OSEM2D and Onco-flash3D reconstruction method and compared reconstruction methods between applied Gaussian post-filtering 5mm and not applied as well. Attenuation correction was applied by manual method. And we did Brain SPECT to patient injected 15 mCi of $^{99m}Tc$-HMPAO according to results of Phantom study. Lastly, technologist, MD, PhD estimated the results. Results: The study shows that reconstruction method by Flash3D is better than exiting FBP and OSEM2D when studied using IEC phantom. Flowing by estimation, when using Flash3D, both of 15 sec and 25 sec are needed postfiltering 5 mm. And 8 times are proper for subset 8 iteration in Flash3D. OSEM2D needs post-filtering. And it is proper that subset 4, iteration 8 times for 15sec and subset 8, iteration 12 times for 25sec. The study regarding to injected doses for a patient and study time, combination of input parameter-15 sec/frame, LEHR collimator, analysing program-Flash3D, subset 8, iteration 8times and Gaussian post-filtering 5mm is the most appropriate. On the other hands, it was not appropriate to apply LEUHR collimator to 1-day subtraction method of Diamox study because of lower sensitivity. Conclusions: We could prove that there was also an advantage of short study time effectiveness in Dual camera same as Triple gamma camera and get great result of alternation from existing fan-beam collimator to parallel collimator. In addition, resolution and contrast of new method was better than FBP method. And it could improve sensitivity and accuracy of image because lesser subjectivity was input than Metz filter of FBP. We expect better image quality and shorter study time of Brain SPECT on Dual detector system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.39-48
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• 2013

This paper develops a 2-D moving least squares(MLS) difference method for Stefan problem by extending the 1-D version of the conventional method. Unlike to 1-D interfacial modeling, the complex topology change in 2-D domain due to arbitrarily moving boundary is successfully modelled. The MLS derivative approximation that drives the kinetics of moving boundary is derived while the strong merit of MLS Difference Method that utilizes only nodal computation is effectively conserved. The governing equations are differentiated by an implicit scheme for achieving numerical stability and the moving boundary is updated by an explicit scheme for maximizing numerical efficiency. Numerical experiments prove that the MLS Difference Method shows very good accuracy and efficiency in solving complex 2-D Stefan problems.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1109-1114
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• 2022

The SMART (System-integrated Modular Advanced ReacTor) is an integral-type small modular reactor developed by KAERI (Korea Atomic Energy Research Institute). This paper discusses the feasibility and applicability of a 3D-based equivalent model using dynamic condensation method for seismic analysis of a SMART control rod drive mechanism. The equivalent model is utilized for complicated seismic analysis during the design of the SMART. While the 1D-based beam-mass equivalent model is widely used in the nuclear industry for its calculation efficiency, the 3D-based equivalent model is suggested for the seismic analysis of SMART to enhance the analysis accuracy of the 1D-based equivalent model while maintaining its analysis efficiency. To verify the suggested model, acceleration response spectra from seismic analysis based on the 3D-based equivalent model are compared to those from the 1D-based beam-mass equivalent model and experiments. The accuracy and efficiency of the dynamic condensation method are investigated by comparison to analysis results based on the conventional modeling methodology used for seismic analysis.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.515-528
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• 1995

The human genomic deoxyribonucleic acid(DNA) was extracted from the pulp, dentin of 22 teeth by clelex, phenol methods. Samples of the tooth-derived DNA were amplified by polymerase chain reaction(PCR), electrophosed for sex determination by detection of X-Y homologus amelogenin gene and D1S80 locus detection The following results have been achieved. 1. Chelex and phenol method are effective to sex determination in the pulp and dentin 2. Chelex method is not suitable for detection of D1S80 locus. 3. Concentration and purity of DNA for teeth using chelex method is lower than using phenol method. From the above investigation, chelex method is simple, rapid for sex determination, but it is not suitable for detection of VNTRs.

• Journal of Information Display
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• v.10 no.1
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• pp.6-15
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• 2009

In this paper, a new approach is proposed for the efficient generation of computer-generated holograms (CGHs) using the spatially redundant data on a 3D object and the novel look-up table (N-LUT) method. First, the pre-calculated N-point principle fringe patterns (PFPs) were calculated using the 1-point PFP of the N-LUT. Second, spatially redundant data on a 3D object were extracted and re-grouped into the N-point redundancy map using the run-length encoding (RLE) method. Then CGH patterns were generated using the spatial redundancy map and the N-LUT method. Finally, the generated hologram patterns were reconstructed. In this approach, the object points that were involved in the calculation of the CGH patterns were dramatically reduced, due to which the computational speed was increased. Some experiments with a test 3D object were carried out and the results were compared with those of conventional methods.

• Journal of Ginseng Research
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• v.36 no.2
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• pp.205-210
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• 2012

For quality control of components in Korean red ginseng powder and extract, a new method for simultaneous quantification of 12 ginsenosides ($Rg_1$, Re, Rf, $Rh_1$, $Rg_2$[S], $Rg_2$[R], $Rb_1$, Rc, $Rb_2$, Rd, $Rg_3$[S], and $Rg_3$[R]) was studied. Compared to the official method for quantification of marker substances (ginsenosides $Rg_1$ and $Rb_1$), the proposed methods were guaranteed by in-house method validation. Several criteria such as linearity, specificity, precision and accuracy were evaluated. For red ginseng powder, recovery (averaging 95% to 105%) was calculated, and analysis of variance was carried out to estimate the relative standard deviation (0.20% to 2.12%). For red ginseng extract, the average recovery rate was 90% to 99% and the relative standard deviation was 0.39% to 2.40%. These results indicate that the proposed method could be used in the laboratory for determination of 12 ginsenosides in red ginseng powder and extract. In addition, this method was found to be suitable for quality control of ginseng products and potentially offer time and cost benefits.

• Geophysics and Geophysical Exploration
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• v.8 no.3
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• pp.207-217
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• 2005

We present a new approximate formulation of the integral equation (IE) method for models with variable background conductivity. This method overcomes the standard limitation of the conventional If method related to the use of a horizontally layered background only. The new approximate IE method still employs the Green's functions for a horizontally layered 1-D model. However, the new method allows us to use an inhomogeneous background with the IE method. The method was carefully tested for modeling the EM field for complex structures with a known variable background conductivity. It can find wide application in modeling EM data for multiple geological models with some common geoelectrical features, like a known inhomogeneous overburden, or salt dome structures.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.89-96
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• 1995

The application of the 4-pole parameter method with 1 - D theory is acceptable for intake system analysis. However, the limitaion appears during the analysis of complicated intake system since this method is developed based on the plane wave thoery. For the intake system analysis, the usage of BEM(Boundary Element Method) is introduced describing its disadvantage. To combine benefits of both method. a hybrid method is introduced. This hybrid method consists of the 4-pole parameter with I-D theory and BEM. The developed method is applied to an automobile intake system analysis to obtain the transmission loss.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.50.1-50.1
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• 2005