• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.25-30
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• 2010

Purpose: This study was conducted to estimate the changes of corrected diopter and corrected visual acuity with the change in vertex distance. Also we aimed to provide basic data for refraction test. Methods: Using the trial lens, we measured the corrected diopter and corrected visual acuity after performing binocular balance test. We measured the changes of corrected diopter and corrected visual acuity in change of vertex distance. We analyzed statistical significance and relations between vertex distance and corrected diopter and corrected visual acuity. Results: There was no difference in corrected diopter with the change of vertex distance within -1.00D, but the corrected diopter increased with it over - 1.25D. In particular, the change of diopter was largest when the vertex distance increased 15 mm. At over 11.00D, there was large changes of diopter with the changes of vertex distance at 5 mm, 10 mm and 15 mm. On correlation analysis between the vertex distance and the corrected diopter, there was strong correlation (r=0.999 at 5 mm increase of vertex distance, r=0.982 at 10 mm increase and r=0.957 at 15 mm increase) and also there was significant (p<0.01). At the change of visual acuity in increased of vertex distance, the range of a decrease in visual acuity was large when the changes of vertex distance was largest. On correlation analysis between the vertex distance and the corrected visual acuity, there was strong correlation (r=0.969 at 5 mm increase of vertex distance, r=0.985 at 10 mm increase and r=0.994 at 15 mm increase) and also there was significant (p<0.01). Conclusions: The vertex distance was very important at the refraction test and at wearing spectacle. On correlation analysis between the vertex distance and the corrected diopter, and the corrected visual acuity, there was strong correlation and statistically significant. Therefore, the vertex distance should be kept at the refraction using trial lens, and the best fitting was made not to slipping forward, and so we suggested regular refitting of spectacle and the managing method of spectacle were educated to the spectacle wearers.

• Journal of the Korean Mathematical Society
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• v.57 no.5
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• pp.1119-1133
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• 2020

In this paper, we derive an upper bound for the distance from a point in the immediate basin of a root of a complex polynomial to the root itself. We establish that if z is a point in the immediate basin of a root α of a polynomial p of degree d ≥ 12, then ${\mid}z-{\alpha}{\mid}{\leq}{\frac{3}{\sqrt{d}}\(6{\sqrt{310}}/35\)^d{\mid}N_p(z)-z{\mid}$, where N_p is the Newton map induced by p. This bound leads to a new bound of the expected total number of iterations of Newton's method required to reach all roots of every polynomial p within a given precision, where p is normalized so that its roots are in the unit disk.

• Bulletin of the Korean Mathematical Society
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• v.55 no.1
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• pp.115-137
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• 2018

Let $R_{u{^2},v^2,w^2,p}$ be a finite non chain ring ${\mathbb{F}}_p[u,v,w]{\langle}u^2,\;v^2,\;w^2,\;uv-vu,\;vw-wv,\;uw-wu{\rangle}$, where p is a prime number. This ring is a part of family of Frobenius rings. In this paper, we explore the structures of cyclic codes over the ring $R_{u{^2},v^2,w^2,p}$ of arbitrary length. We obtain a unique set of generators for these codes and also characterize free cyclic codes. We show that Gray images of cyclic codes are 8-quasicyclic binary linear codes of length 8n over ${\mathbb{F}}_p$. We also determine the rank and the Hamming distance for these codes. At last, we have given some examples.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.6
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• pp.340-345
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• 2002

In this paper, we deal with the following facility location problem. Given a set P of n points in the plane, find two (discrete) centers p and q in P that minimize the sum of there distance plus the distance of any other point to the closer center. In this paper, we propose an Ο(n$^2$1ogn)-time algorithm to compute the two centers.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.1
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• pp.147-156
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• 2020

The functional equation related to a distance measure f(pr, qs) + f(ps, qr) = M(r, s)f(p, q) + M(p, q)f(r, s) can be generalized a sum form functional equation as follows $${\frac{1}{n}}{\sum\limits_{i=0}^{n-1}}f(P{\cdot}{\sigma}_i(Q))=M(Q)f(P)+M(P)f(Q)$$ where f, g is information measures, P and Q are the set of n-array discrete measure, and σ_i is a permutation for each i = 0, 1, ⋯, n-1. In this paper, we obtain the hyperstability of the above type functional equation.

• Educational Technology International
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• v.9 no.2
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• pp.39-56
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• 2008

This paper investigates the relationship between the structural characteristics of a virtual CoP and the measures of social network analysis. Several implications were developed by the results of the study First, the study, based on reviews of both the CoP and SNA literature, identified specific structural measures of SNA; connectedness, geodesic distance, and density. Second, the formal CoP investigated in this study showed greater development that the classic, informal CoP in terms of the structural dimension of a CoP. The results show that those measures of social network analysis provide an illuminating way to better understand the structural properties of CoP's. Implications of the study with some suggestions for future research are provided.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.1
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• pp.27-36
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• 2020

Background: Exercise in the quadruped position is performed to improve body and shoulder stability. This study examined the muscle activity of the trunk muscles according to the distance of the weight shift when lifting one leg in the quadruped position. Methods: Ten healthy 20 to 40 years old males were tested as subjects. All subjects moved their body weight to 0, 5, and 10cm on the opposite side of the leg lifter while maintaining the quadruped position. The surface electrodes recorded the electromyography data during the one leg lifting. Results: As the weight shift distance was increased, there was a significant difference in muscle activity of both serratus anterior, multifidus and internal oblique muscles (p<.05). Left and right serratus anterior and right internal oblique were most activated when weight shift distance was 0cm (p<.05). Conclusion: Shoulder and lumbar stabilization exercises should be applied in the absence of a weight shift distance during quadruped exercise.

• Physical Therapy Korea
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• v.7 no.1
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• pp.46-54
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• 2000

The purpose of this study is to determine whether movement strategies affect functional forward reach distance in a standing position. Forty-seven healthy subjects were selected for this study: 23 men and 24 women, with an average age of 22.3. Functional forward reach distances were measured as hip strategy and squat strategy (included knee and ankle movement strategy) in a standing position, respectively. The mean values of functional forward reach distance in hip strategy, squat strategy were 33.57 cm, 29.48 cm, respectively. There was significantly difference in functional forward reach distance between hip strategy and squat strategy(p<.001). There was no difference of functional forward reach distance between male and female in hip strategy, but there was significant difference in other strategy(p<.05). These results suggest that movement strategies should be considered during functional forward reach test in standing. Further study is required to determine whether movement strategies affect functional reach distance in elderly and disabled groups.

• Journal of Ecology and Environment
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• v.40 no.2
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• pp.84-88
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• 2016

To understand the effects of habitat characteristics on the genetic diversity of Persicaria thunbergii, three sites of different environmental conditions in a water system were surveyed. Site A was the closest to the source of the water system, and there was a dam between sites A and B. Site C is located on the lowest downstream in the water system. Vegetation survey of four quadrats at each site was performed, and soil samples were collected for physicochemical analysis. Random amplification of polymorphic DNA (RAPD) analysis of ten P. thunbergii individuals at each site was conducted to calculate population genetic diversity and genetic distance among populations. Soil was sterile sand at site A, whereas loamy soil at sites B and C. A pure stand of P. thunbergii appeared at site A, while other species occurred together (such as Humulus japonicus and Phragmites australis) at sites B (Shannon-Wiener index; $H_B=0.309$) and C ($H_C=0.299$). Similar to the species diversity, genetic diversity (Nei's gene diversity; h) within population of site A ($h_A=0.2381$) was relatively lower than sites B ($h_B=0.2761$) and C ($h_C=0.2618$). However, site C was separated from sites A and B in genetic distance rather than the geographical distance (Nei's genetic distance; A~B, 0.0338; B~C, 0.0685; A~C, 0.0833).

• Journal of Distribution Science
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• v.17 no.12
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• pp.63-70
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• 2019

Purpose: This study was to propose effective deployment of automatic external defibrillators (AEDs) installed at general supermarkets. Research design, data, and methodology : We conducted interview and data surveys on 72 large distributors in Seoul and Gyeonggi province in South Korea. The content of this survey was consisted of general status on the general supermarkets, AED deployment and management regarding public access defibrillation (PAD). G^⁎Power (v 3.1.9.4; Universität Kiel, Kiel, Germany) was also used to analyze statistical power. Radius and actual distance, radius and retrieval time were compared by t-test at α=.05. respectively. Results : Difference between the radius (102.7 meters) and the actual distance (187.8 meters) was 85.1m, it had statistically significant difference (p<.001). The actual distance was longer compared to the radius distance. Difference between the radius (114.1 seconds) and the retrieval time (208.7 seconds) was 94.6s, it had statistically significant difference (p<.001). The retrieval time took longer compared to the radius time as well. Conclusions : The finding shows that only 45.9% of the general supermarkets are satisfied with the actual AED coverage within 3 minutes. This needs to enhance AED deployment to reduce defibrillation time and AED management to boost application in South Korea.