• Journal of the Korean Data and Information Science Society
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• v.26 no.4
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• pp.931-946
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• 2015

Many multiple life insurance products consider benefits that are contingent on the combined survival status of two lives. To value premiums of the insurance products accurately, we need to consider the impact of the survivorship of one life on another. To show a dependence relation between married couple, we calculate correlation coefficients by using married couples data from National Pension Service and the results show some positive dependence between them. Moreover, by analyzing the death after bereavement, we find a evidence that mortality rates increase after the death of a spouse and, in addition, that this phenomenon, the broken-heart syndrome, diminishes over time. The results of this study can support the method to calculate the premium of multiple life insurance reflecting more realistic joint mortality rates.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.253-263
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• 2021

Machine learning is the process of constructing a cost function using learning data used for learning and an artificial neural network to predict the data, and finding parameters that minimize the cost function. Parameters are changed by using the gradient-based method of the cost function. The more complex the digital signal and the more complex the problem to be learned, the more complex and deeper the structure of the artificial neural network. Such a complex and deep neural network structure can cause over-fitting problems. In order to avoid over-fitting, a weight decay regularization method of parameters is used. We additionally use the value of the cost function in this method. In this way, the accuracy of machine learning is improved, and the superiority is confirmed through numerical experiments. These results derive accurate values for a wide range of artificial intelligence data through machine learning.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.840-849
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• 2013

This paper presents a statistical approach to analyze electrical tree inception voltage, electrical tree breakdown voltage and tree breakdown time of unsaturated polyester resin subjected to AC voltage. The aim of this work was to show that Weibull and lognormal distribution may not be the most suitable distributions for analysis of electrical treeing data. In this paper, an investigation of statistical distributions of electrical tree inception voltage, electrical tree breakdown voltage and breakdown time data was performed on 108 leaf-like specimen samples. Revelations from the test results showed that Johnson SB distribution is the best fit for electrical tree inception voltage and tree breakdown time data while electrical tree breakdown voltage data is best suited with Wakeby distribution. The fitting step was performed by means of Anderson-Darling (AD) Goodness-of-fit test (GOF). Based on the fitting results of tree inception voltage, tree breakdown time and tree breakdown voltage data, Johnson SB and Wakeby exhibit the lowest error value respectively compared to Weibull and lognormal.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.173-183
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• 2017

The purpose of this study is to develop students' creativity and artistic sensitivity by developing a convergence education program that links various subjects, including mathematics, science, and art based on design. Design is done in almost every human activity that pursues beauty and implements cultural value through patterns and images. We have developed three programs for elementary school students and two programs for middle school students, taking into consideration the achievement standards and curriculum content appropriate for the 2015 revised curriculum. It was assessed by a panel of five educational experts during the development and demonstration courses to evaluate the feasibility of the development program. The development program can enhance the design literacy and design sense of elementary and junior high school students and can be used convergent educational contents that can be applied in the free-semester system activities of junior high school. Through this program, adolescents who will lead the future design society will be able to acquire the sense of design, literacy, and design ability as design consumers and producers.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.253-259
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• 1981

A study was made to find out a new method of calculating the survival rate of a fish population from length composition and growth equation. 1. In the steady state of the fish population, let the total mortality rate be z, the age of complete recruitment a, the oldest age in the catch b and the average between the age of complete recruitment and the oldest age in the catch Ut, then we have $$U_{t}\;=\;\frac{a-b\;{e xp}\{-z(b-a)\}}{1-\;{e xp}\{-z(b-a)\}}+\frac{1}{z}{\cdots}{\cdots}{\cdots}{\cdots}{\cdots}$$(1) And let b be infinite, then we obtain $$Z=\frac{1}{U_t-a}{\cdots}{\cdots}{\cdots}{\cdots}{\cdots}{\cdots}$$ (2) 2. Calculating numerical value of $U_t$ from age composition table and growth equation, and substitute in (1) for it, we may obtain the value of z and $e^{-z}$. 3. This method is applied to a case of mackerel and horse mackerel in the coastal waters of Korea, with the following results : Total mortality rate-Mackerel : 0.87909, Horse mackerel : 2.22327, Survival rate-Mackerel : 0.41516, Horse Mackerel : 0.10825, 95 percent confidence Interval of survival rate-Mackerel : $0.35966{\sim}0.47264$, Horse mackerel : $0.06897{\sim}0.14974$

• Spatial Information Research
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• v.17 no.4
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• pp.455-462
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• 2009

A method to find the nearly optimal PSNR values for compression was tried to remotely sensed images. There is no rule to find the best wavelet pairs for image processing. The expected wavelet pairs following the suggested algorithm showed the optimal result for various kinds of images. Firstly, the PSNR variations with three wavelet families were analyzed. In many cases the longer wavelet filter shows the higher PSNR value, but the rate is getting less in orthogonal wavelet families. Wavelets with moderate filter length are suggested at the point of computational cost. For biorthogonal families it was hard to predict from the length of filters. Multiresolution wavelet analysis was used up to level 3 with three kinds of wavelet families. Biorthogonal wavelet family showed irregular pattern to get the maximum PSNR values, while orthogonal wavelet families showed regular pattern. In orthogonal wavelet families the nearly optimal wavelet pair can be predicted from the level 1.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.10-17
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• 2016

This paper presents a laboratory validation of a new approach for Finite Element Model Updating(FEMU) on short-span bridges by combining ambient vibration measurements with static load input-deflection output measurements. The conventional FEMU approach based on modal parameters requires the assumption on the system mass matrix for the eigen-value analysis. The proposed approach doesn't require the assumption and even provides a way to update the mass matrix. The proposed approach consists of two steps: 1) updating the stiffness matrix using the static input-deflection output measurements, and 2) updating the mass matrix using a few lower natural frequencies. For a validation of the proposed approach, Young's modulus of the laboratory model was updated by the proposed approach and compared with the value obtained from strain-stress tests in a Universal Testing Machine. Result of the conventional FEMU was also compared with the result of the proposed approach. It was found that proposed approach successfully estimated the Young's modulus and the mass density reasonably while the conventional FEMU showed a large error when used with higher-modes. In addition, the FE modeling error was discussed.

• Journal of the Society of Disaster Information
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• v.11 no.3
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• pp.436-445
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• 2015

A flood loss estimation toolbox was developed within GIS software. This toolbox is for anyone who is interested in the flood loss estimation, and uses data accessible to public. In particular, the loss estimation framework in the toolbox is distinct in that the inventory items are individually dealt with. The toolbox was applied to estimate the economic loss from a levee failure event in 2002. The estimated loss was a little larger than the reported value. The difference is probably due to the asset values and the damage functions for each inventory item, which have to be updated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3510-3516
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• 2010

In this paper to make young children to learn habits of the animals, crying, features, and English and Korean language, The system was developed to target the zoo various animals exist. If young child places a doll on the front of interesting animal, then young child can learn to look through the display connected to the model. The zoo is reducing the current appearance of the zoo, sensors that can recognize animals are attached to each cage. Attached to each sensor has a unique ID, If this approach recognizes a doll baby and will transmit a unique ID to the handler. Transmitted ID search the matched value sent from the database to retrieve the content and then the content is to be output through the output device. Also if the doll near the animal's room, young children find out animal sound and basic learning by multimedia effects. At the same time Korean, English, Mathematics are learned.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.1
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• pp.62-75
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• 2022

In this study, experiential STEAM program using 3D printer was produced focusing on the content elements of 'solar' in the 2015 revised science curriculum, and in order to find out the effectiveness of the STEAM program, analyzed creative problem solving, STEAM attitude, and STEAM satisfaction by applying it to two middle school 77 students simple random sampled. The results of this study are as follows. First, a solar tactile model was produced using a 3D printer, and a program was developed to enable students to actively learn experience-oriented activities through visual impairment experiences. Second, in the response sample t-test by the difference in pre- and post-score of STEAM attitude tests, significant statistical test results were shown in 'interest', 'consideration', 'self-concept', 'self-efficacy', and 'science and engineering career choice' sub-factors except 'consideration' and 'usefulness / value recognition' sub-factors (p<.05). Third,, the STEAM satisfaction test conducted after the application of the 3D printer-based STEAM program showed that the average value range of sub-factors were 3.66~3.97, which improved students' understanding and interest in science subjects through the 3D printer-based STEAM program.