• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.442-448
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• 2002

In the earth telescope for space observation, the adaptive optical (AO) system that immediately compensates atmospheric turbulence is helpful to get high-resolution images. An adaptive optics for earth telescopes is very attractive, since the Earth telescopes can be made at lower costs and have larger optical apertures than space telescopes. Generally. in order to remove the wavefront error produced by atmospheric turbulence, a deformable mirror, whose surface shape changes in a controllable way in response to a drive signal, is used. The characteristics and patterns of actuators are very important for the effective control of a deformable mirror. The mirror surface shape deformed by one actuator is defined as an influence function and the deformable mirror can be effectively modeled and designed using this influence function. In this paper. by simplifying the actual influence function obtained by FEM analyses into the Gaussian function and introducing the coupling coefficient between actuators, the influence function is constructed. The proper coupling coefficient of the target system can be obtained by performance analyses of a deformable mirror for various coupling coefficients. Using the constructed influence function, the deformable mirror with equally spaced triangular and square actuator patterns is analyzed for various spacings and an effective actuator pattern is proposed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.653-659
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• 2015

A new formulation of the non-dimensional dynamic influence function method, which is a type of the meshless method, is introduced to extract highly accurate eigenvalues of clamped plates with arbitrary shape. Originally, the final system matrix equation of the method, which was introduced by the author in 1999, does not have a form of algebraic eigenvalue problem unlike FEM. As the result, the non-dimensional dynamic influence function method requires an inefficient process to extract eigenvalues. To overcome this weak point, a new approach for clamped plates is proposed in the paper and the validity and accuracy is shown in verification examples.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.6
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• pp.2069-2085
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• 2021

A Social Networking Service (SNS) platform provides digital footprints to discover users' interests and track the social diffusion of product adoptions. How to identify a small set of seed users in a SNS who is potential to adopt a new promoting product with high probability, is a key question in social networks. Existing works approached this as a social influence maximization problem. However, these approaches relied heavily on text information for topic modeling and neglected the impact of seed users' relation in the model. To this end, in this paper, we first develop a general product adoption function integrating both users' interest and social influence, where the user interest model relies on historical user behavior and the seed users' evaluations without any text information. Accordingly, we formulate a product adoption maximization problem and prove NP-hardness of this problem. We then design an efficient algorithm to solve this problem. We further devise a method to automatically learn the parameter in the proposed adoption function from users' past behaviors. Finally, experimental results show the soundness of our proposed adoption decision function and the effectiveness of the proposed seed selection method for product adoption maximization.

• Journal of Industrial Technology
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• v.16
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• pp.123-129
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• 1996

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. In order to obtain the natural frequency by the presented method, the first step to take is to obtain the deflection influence surfaces. In design and analysis of any structure, the first step to be taken is to obtain this deflection influence surfaces. Any method can be used for this purpose. Then using this surfaces, deflections, slopes, moments, shears, and natural frequencies can be obtained by differentiating either the continuous function or discrete function defined at certain points. The merit of the presented method is that the natural frequency can be obtained by the deflection influence surfaces obtaining which is the first step in structural analysis.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.129-134
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• 2004

In this study, we investigate the effects of the weight function in the bounded influence regression quantile (BIRQ) estimator for the AR(1) model with additive outliers. In order to down-weight the outliers of X-axis, the Mallows' (1973) weight function has been commonly used in the BIRQ estimator. However, in our Monte Carlo study, the BIRQ estimator using the Tukey's bisquare weight function shows less MSE and bias than that of using the Mallows' weight function or Huber's weight function.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.219-229
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• 2018

The purpose of this study was to investigate the relationship among Exercising Activity, muscle mass, Muscular strength and cognitive function of 274 elderly people aged 65 years and older living in Seoul and Gyeonggi-do As for the data collection methods, were measured the Exercising Activity, muscle mass and muscular strength and the Korean version of Mini Mental State Examination(MMSE-K) and digit span test were measured. The results are as follows First, there was a statistically significant correlation between Exercising activity, muscle mass, muscular strength, and cognitive function of the elderly. Second, Exercising activity of the elderly showed a positive (+) influence on muscle mass, muscular strength, and cognitive function. Third, the muscle mass of the elderly showed a statistically significant (+) influence on muscular strength and cognitive function. Fourth, the strength of the elderly showed a positive (+) influence on cognitive function.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.568-574
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• 2012

Turbulent boundary layer noise is already a significant contributor to sonar self noise. For developing acoustic window of sonar system to reduce self noise, a parametric study of design factors of acoustic window is presented. Distance of sensor array from acoustic window, material and damping layer are studied as design factors to influence in the characteristics of the transfer function of self noise. As the result these design factors make change the characteristics of transfer function slightly. Among design factors the location of sensor array is most important parameter in the self noise reduction.

• Journal of the Korean Data and Information Science Society
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• v.11 no.2
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• pp.181-188
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• 2000

The shape of an M-estimation function is generally determined in the sense of either/both maximizing efficiency of an M-estimator at the model or/and bounding the influence function of an M-estimator. We propose an empirical method of choosing a value of the bending constant in Huber's ${\psi}-function$, which is the most widely used M-estimation function when estimating the location parameter.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.221-226
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• 2006

We usually use two techniques(influence function and local influence) for detecting outliers. But, we cannot use these difficult techniques in elementary industrial statistics course for college students. We can use some simple graphical methods(box plot, dandelion seed plot, influence graph and cumulative deletion plot) for univariate and bivariate outlier detection and outlier effect in elementary industrial statistics course for college students.

• Journal of Information Management
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• v.28 no.3
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• pp.1-20
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• 1997

It has been shown that there are four information demensions which have positive influence on perceived utility of information. Subsequently, I have investigated the antecedents of these four information dimensions. The quality of the relationship, interpersonal characteristics and interaction have positive influence on marketing information quality. In addition, Marketing personnel interpersonal characterstics have positive influence on relationship quality. Integration has positive influence on interaction between marketing personnel and R&D personnel. Finally, Organizational climate has positive influence on interpersonal characteristics and integration between marketing function and R&D function.