• Journal of applied mathematics & informatics
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• v.41 no.5
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• pp.1115-1128
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• 2023

In this paper, a novel hybrid method for multi-focus image fusion is proposed. The method combines the advantages of wavelet transform-based methods and focus-measure-based methods to achieve an improved fusion result. The input images are first decomposed into different frequency sub-bands using the discrete wavelet transform (DWT). The focus measure of each sub-band is then calculated using the Laplacian of Gaussian (LoG) operator, and the sub-band with the highest focus measure is selected as the focused sub-band. The focused sub-band is sharpened using an unsharp masking filter to preserve the details in the focused part of the image.Finally, the sharpened focused sub-bands from all input images are fused using the maximum intensity fusion method to preserve the important information from all focus images. The proposed method has been evaluated using standard multi focus image fusion datasets and has shown promising results compared to existing methods.

• Current Optics and Photonics
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• v.8 no.2
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• pp.170-182
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• 2024

The dimensional accuracy and consistency of a dual oil circuit centrifugal fuel nozzle are important for fuel distribution and combustion efficiency in an engine combustion chamber. A point cloud measurement method was proposed to solve the geometric accuracy detection problem for the fuel nozzle. An improved variance focus measure operator was used to extract the depth point cloud. Compared with other traditional sharpness evaluation functions, the improved operator can generate the best evaluation curve, and has the least noise and the shortest calculation time. The experimental results of point cloud slicing measurement show that the best window size is 24 × 24 pixels. In the height measurement experiment of the standard sample block, the relative error is 2.32%, and in the fuel nozzle cone angle measurement experiment, the relative error is 2.46%, which can meet the high precision requirements of a dual oil circuit centrifugal fuel nozzle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.331-332
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• 2010

• Communications of the Korean Mathematical Society
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• v.37 no.2
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• pp.497-502
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• 2022

Existence and uniqueness for fractional differential equations satisfying a general nonlocal initial or boundary condition are proven by means of Schauder's fixed point theorem. The nonlocal condition is given as an integral with respect to a signed measure, and includes the standard initial value condition and multi-point boundary value condition.

• Journal of the Korean Statistical Society
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• v.5 no.1
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• pp.19-28
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• 1976

In empirical study for fitting a multiple linear regression model for successive cross-sections data observed on the same set of independent variables over several time periods, one often faces the problem of poor $R^2$, the multiple coefficient of determination, which provides a standard measure of how good a specified regression line fits the sample data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1095-1101
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• 2008

The desirable method to diagnose abnormal blood pressure is to measure and manage blood pressure continuously and regularly. However, the sphygmomanometers that are based on a cuff have faults in that they can not measure the blood pressure continuously and they cause an unpleasant feeling. Therefore, it is essential to develop a new measuring method that causes no pain and that can obtain blood pressure continuously without any unpleasant feeling. Thus, we propose here a regression method to estimate the systolic blood pressure by using the PTTL(pulse transit time on leg) with some body parameters which are chosen from the relational analysis with systolic blood pressure. The data we use to make the regression model were obtained in triplicate from each of 50 males who were from 18 to 35 years. And we made estimation experiments of blood pressure on 10 males who did not take part in the making the regression model. According to the results, the proposed method showed a mean error of 4.00 mmHg and the standard variance was 2.45 mmHg. When we comparing the results of the proposed method with the rule of American National Standards Institute of the Association of the Advancement of Medical Instruments(ANSI/AAMI), the results satisfied the rule of a mean error less than 5 mmHg and a standard variance less than 8 mmHg. Therefore we were able to validate the usefulness of the proposed method.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.102-107
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• 2007

A fast response $CO_2$ ($fCO_2$) analyzer for real-time measurement of carbon dioxide concentration during transient states of internal combustion engines has been developed. This analyzer uses non-dispersive infrared absorption (NDIR) technique for measuring $CO_2$ concentration and Kalman filter for removing noise components from output signals. The analyzer has good linearity, repeatability and drift with a response time of 11 ms; it is sufficiently fast to detect $CO_2$ concentration during transient states of internal combustion engines. The $fCO_2$ analyzer was used to measure transient $CO_2$ concentration of exhaust gas of the SI engine with a standard gas analyzer, and the signal of the $fCO_2$ analyzer was compared to that of the standard gas analyzer. The two concentrations were well matched during the steady state, and the $fCO_2$ analyzer could measure the variations of $CO_2$ concentration during the transient state.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.645-648
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• 2005

Microscopy has enabled the development of many advanced technologies, and higher level microscopic techniques are required according to the increase of research in nano-technology and bio-technology fields. Therefore, in many applications, we need to measure the dimension of micro-scale parts accurately, not just to observe their shapes. To establish the meter-traceability in microscopy, gratings have been widely used as a magnification standard. KRISS provides the certification service of magnification standards using an optical diffractometer and a metrological AFM (MAFM). They are based on different measurement principles, and so can give complementary information for each other. In this paper, we describe the configuration of each system and measurement procedures to certificate grating pitch values of magnification standards. Several measurement results are presented, and the discussion about them are also given. Using the optical diffractometer, we can calibrate a grating specimen with uncertainty of less than 50 pm. The MAFM can measure a grating specimen of down to 100 nm pitch value, and the calibrated values usually have uncertainty less than 500 pm.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.627-642
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• 2012

The purpose of this study was to develop and validate a teacher's praise dispositions scale(TPDS). On the basis of a literature review of praise, we developed 19 Likert-type items to measure praise dispositions of elementary and secondary school teachers. The developed scale was examined with 342 teachers. With an exploratory factor analysis we extracted 3 sub-factors of the scale consisted of 16 items; frequency, intention, and standard of praise. Cronbach's ${\alpha}$ coefficients of sub-scales were from .60 to .85 and split-half reliabilities were from .60 to .84. A confirmatory factor analysis was conducted to assess the suitability of three components model. It was found that some correlation coefficients, not all of them, between gratitude disposition and praise disposition were statistically significant. It suggested that teachers'praise disposition scale is related to gratitude disposition but is not the same scale. In conclusion, TPDS could be used to measure praise dispositions of teachers. However, for further validity and reliability, repeated research is necessary.

• Journal of Arbitration Studies
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• v.25 no.1
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• pp.65-86
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• 2015

Under current international investment law clear criteria to determine standards of indirect expropriation are absent. Arbitral tribunals determine on a case-by-case whether an indirect expropriation has occurred by conducting a fact-based inquiry. However, three common determination standards can be inferred by analyzing prior arbitration cases. The appropriate analytical framework that can be applied to determine whether a state's measure constitutes an indirect expropriation is as follows. i) the degree of economic invasion of the state's action into the foreign investor's property rights and durability of the period, ii) interference with the foreign investor's distinct and reasonable investment-backed expectations, and iii) the nature, purpose and character of the state's measure. Therefore, it is necessary to fully acknowledge and to utilize strategically this determination standard. However, derived standards cannot be applied to all disputes en masse. So, it is desirable to exclude ambiguity and to clearly define the determination standard of indirect expropriation in investment agreements, since arbitral tribunals can apply different determination standards on a case-by-case basis. And, based on the discussions until now, more developed standards and direction in response to demand should be established through consistent analysis and review of precedents related to indirect expropriation. Lastly, This study is expected to be a useful guideline to prepare a necessary countermeasure to prevent dispute related to indirect expropriation beforehand or in case of dispute occurrence.