• 한국노년학
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• v.29 no.3
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• pp.971-986
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• 2009

This research investigated how the participation of various social activities affects cognitive function in middle-aged and elderly population. To examine the relation between the participation of various social activities and cognitive function, we used data from the Korean Longitudinal Study of Ageing. Social activities were classified into four types as religious ritual, leisure, public association and ascriptive association activities, and MMSE-K score was used to measure cognitive function. Results from multiple regression analyses after adjusting for socio-economic status and health status show that the participation in religious and leisure activities have positive effects on cognitive function in middle-aged and elderly population. Participation in leisure activities in middle-aged male group helps preserve cognitive function, and leisure activity and ritual activity are significantly related to cognitive function in middle-aged female group. Meanwhile the participation in religious and leisure activities have positive effects on cognitive function in elderly male and female group. Based on these findings, we suggest that various programs to support the participation of elderly population in social activities should be developed for healthy life for the elderly.

• International Journal of Advanced Culture Technology
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• v.10 no.2
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• pp.201-212
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• 2022

With the development of sequencing technology, there is a need for technology to predict the function of the protein sequence. Enzyme Commission (EC) numbers are becoming markers that distinguish the function of the sequence. In particular, many researchers are researching various methods of predicting the EC numbers of protein sequences based on deep learning. However, as studies using various methods exist, a problem arises, in which the exact prediction result of the sequence is unknown. To solve this problem, this paper proposes an All Enzyme Commission (AEC) algorithm. The proposed AEC is an algorithm that executes various prediction methods and integrates the results when predicting sequences. This algorithm uses duplicates to give more weights when duplicate values are obtained from multiple methods. The largest value, among the final prediction result values for each method to which the weight is applied, is the final prediction result. Moreover, for the convenience of researchers, the proposed algorithm is provided through the AllEC web services. They can use the algorithms regardless of the operating systems, installation, or operating environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.4
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• pp.490-495
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• 2007

This research aims to examine accuracy and efficiency of the first four moments corresponding to mean, standard deviation, skewness, and kurtosis, which are estimated by a function approximation moment method (FAMM). In FAMM, the moments are estimated from an approximating quadratic function of a system response function. The function approximation is performed on a specially selected experimental region for accuracy, and the number of function evaluations is taken equal to that of the unknown coefficients for efficiency. For this purpose, three error-minimizing conditions are utilized and corresponding canonical experimental regions constructed accordingly. An interpolation function is then obtained using a D-optimal design and then the first four moments of it are obtained as the estimates for the system response function. In order to verify accuracy and efficiency of FAMM, several non-linear examples are considered including a polynomial of order 4, an exponential function, and a rational function. The moments calculated from various coefficients of variation show very good accuracy and efficiency in comparison with those from analytic integration or the Monte Carlo simulation and the experimental design technique proposed by Taguchi and updated by D'Errico and Zaino.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2012.05a
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• pp.61-62
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• 2012

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1983.10a
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• pp.61-64
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• 1983

It is shown that the new window function of Exponential type can be derived from Cheby-chev Identity for the design of FIR filter, and the various kinds of windows which have different characterristics can also be made by changing the coefficients of them oasily

• Bulletin of the Society of Naval Architects of Korea
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• v.5 no.2
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• pp.35-44
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• 1968

The longitudinal cut method of experimental ship wave analysis, originally developed by J.N. Newman, is presented and various plausible sources of error are discussed. A further use of autocorrelation function and crosscorrelation function when two wave systems are superposed is indicated.

• Kyungpook Mathematical Journal
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• v.59 no.2
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• pp.277-291
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• 2019

Using the concept of bounded boundary rotation, we investigate various properties of two new generalized classes of spirallike and Robertson functions of complex order with bounded boundary rotations.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.2
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• pp.19-25
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• 2013

Recently, the high-resolution satellite images is used the land cover and status data for the natural resources or environment management very helpful. The SVM algorithm of image processing has been used in various field. However, classification accuracy by SVM algorithm can be changed by various kernel functions and parameters. In this paper, the typical kernel function of the SVM algorithm was applied to the KOMPSAT-2 image and than the result of land cover performed the accuracy analysis using the checkpoint. Also, we carried out the analysis for selected the SVM kernel function from the land cover of the target region. As a result, the polynomial kernel function is demonstrated about the highest overall accuracy of classification. And that we know that the polynomial kernel and RBF kernel function is the best kernel function about each classification category accuracy.

• Journal of the Chungcheong Mathematical Society
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• v.13 no.2
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• pp.87-98
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• 2001

In this paper, we study hash function, which will take a message of arbitrary length and produce a massage digest of a specified size. The message digest will then be signed. We have to be careful that the use of a hash function h does not weaken the security of the signature scheme, for it is the message digest that is signed, not the message. It will be necessary for h to satisfy certain properties in order to prevent various forgeries. In order to prevent various type of attack, we require that hash function satisfy collision-free property. In section 1, we introduce some definitions and collision-free properties of hash function. In section 2, we study a discrete log hash function and introduce the main theorem as follows : Theorem Suppose $h:X{\rightarrow}Z$ is a hash function. For any $z{\in}Z$, let $$h^{-1}(z)={\lbrace}x:h(x)=z{\rbrace}$$ and denote $s_z={\mid}h^{-1}(z){\mid}$. Define $$N={\mid}{\lbrace}{\lbrace}x_1,x_2{\rbrace}:h(x_1)=h(x_2){\rbrace}{\mid}$$. Then (1) $\sum\limits_{z{\in}Z}s_z={\mid}x{\mid}$ and the mean of the $s_z$'s is $\bar{s}=\frac{{\mid}X{\mid}}{{\mid}Z{\mid}}$ (2) $N=\sum\limits_{z{\in}Z}{\small{s_z}}C_2=\frac{1}{2}\sum\limits_{z{\in}Z}S_z{^2}-\frac{{\mid}X{\mid}}{2}$. (2) $\sum\limits_{z{\in}Z}(S_z-\bar{s})^2=2N+{\mid}X{\mid}-\frac{{\mid}X{\mid}^2}{{\mid}Z{\mid}}$.

• Tuberculosis and Respiratory Diseases
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• v.87 no.3
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• pp.357-367
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• 2024

Background: Obstructive sleep apnea (OSA) is a prevalent sleep disorder associated with various health issues. Although some studies have suggested an association between reduced lung function and OSA, this association remains unclear. Our study aimed to explore this relationship using data from a nationally representative population-based survey. Methods: We performed an analysis of data from the 2019 Korea National Health and Nutrition Examination Survey. Our study encompassed 3,675 participants aged 40 years and older. Risk of OSA was assessed using the STOP-Bang (Snoring, Tiredness during daytime, Observed apnea, and high blood Pressure-Body mass index, Age, Neck circumference, Gender) questionnaire and lung function tests were performed using a portable spirometer. Logistic regression analysis was applied to identify the risk factors associated with a high-risk of OSA, defined as a STOP-Bang score of ≥3. Results: Of 3,675 participants, 600 (16.3%) were classified into high-risk OSA group. Participants in the high-risk OSA group were older, had a higher body mass index, and a higher proportion of males and ever-smokers. They also reported lower lung function and quality of life index in various domains along with increased respiratory symptoms. Univariate logistic regression analysis indicated a significant association between impaired lung function and a high-risk of OSA. However, in the multivariable analysis, only chronic cough (odds ratio [OR], 2.413; 95% confidence interval [CI], 1.383 to 4.213) and sputum production (OR, 1.868; 95% CI, 1.166 to 2.992) remained significantly associated with a high OSA risk. Conclusion: Our study suggested that, rather than baseline lung function, chronic cough, and sputum production are more significantly associated with OSA risk.