• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.273-278
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• 2012

Purpose: Average of the maximum accommodation amplitude of myopia in different generation, early 20's and early 40's were compared according to gender, degree of myopia. Methods: Maximum amplitude of accommodation for each 100 patients of early 20's and 40's were measured with push-up method. Maximum amplitude of accommodation expectations based on Hofstetter formula were classified into three groups of under, normal and excess. Results: The average of amplitude of accommodation was 9.77~11.64 D $(10.77{\pm}2.49D)$ in early 20's and 4.67~6.21 D $(5.34{\pm}1.28D)$ in early 40's. In early 20's, minimum expectations of amplitude of accommodation for under, normal and excess groups were 20%, 75%, and 5%, repectively. In early 40's, excess and under groups were 5% and 18%, repectively, but there was no excess group. Conclusions: According to increasing age, amplitude of accommodation of both age groups showed decreased, and no significant difference was found in degree of myopia with gender. Difference between mean of expected accommodation amplitude and maximum of accommodation amplitude was compared, and it was found that maximum of accommodation amplitude of 20's was smaller than mean of expected accommodation. From the result, it was expected that people in early 20's who have more working times might have festinated accommodative insufficiency than 40's.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1844-1851
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• 2007

This paper presents methods for the compensation of sinusoidal disturbances with unknown amplitude, phase, and time-varying frequency in nonlinear systems. In the previous disturbance accommodation methods, the sinusoidal disturbance with unknown time-invariant frequency was considered. In the proposed method, the disturbance with unknown time-varying frequency is compensated. As for the control structure, two control inputs are designed separately in such a way that one of them is designed for the nonlinear system control without considering the disturbance, and the other one uses the disturbance estimate obtained from the disturbance accommodating observer. The stability analysis is done considering the disturbance estimation error and the numerical simulation demonstrates the proposed approach.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.1-5
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• 2006

In this study, we researched the near addition of presbyopia by the amplitude accommodation method for 40~65ages. The major findings was as follows: 1. The add power was ranged from +0.50Dptr to +3.50Dptr. 2. Add power, +1.50Dptr${\geq}$Add power${\geq}$0.50Dptr was measured in 40~44ages. 3. Add power, +2.00Dptr${\geq}$Add power${\geq}$1.00Dptr was measured in 45~50ages. 4. Add power, +3.00Dptr${\geq}$Add power${\geq}$1.50Dptr was measured in 51~55ages. 5. Add power, +3.50Dptr${\geq}$Add power${\geq}$2.50Dptr was measured in 56~65ages. 6. They put on their glasses for near purpose in 75%.