• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.211-214
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• 2009

In this paper we will outline the opportunities for flexible OLED devices, both for display and solid-state lighting applications. We will present our recent data, and discuss future challenges, for low power consumption phosphorescent OLED technology fabricated on flexible substrates to enable a new generation of energy efficient electronic devices.

• Korean Journal of Mathematics
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• v.27 no.2
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• pp.329-342
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• 2019

In this paper, we introduce the notion of L-fuzzy semi-prime ideals and the radical of L-fuzzy ideals in universal algebras and make a theoretical study on their basic properties.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.272-276
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• 2004

Great strides in organic light emitting device (OLED) technology have resulted in a number of commercial products. To continue this growth into large area displays, for example televisions, an understanding of the mechanisms that drive the OLED device efficiency and lifetime performance is critical. In this work, we consider maximizing the efficiency lifetime product based on phosphorescent OLED ($PHOLED^{TM}$) technology. We report green PHOLEDs with luminous efficiency of 82 cd/A, 5.7 V and 10,000 hours lifetime at 1,000 cd/$m^2$,red PHOLEDs with CIE of (0.67,0.33), 11 cd/A and 35,000 hours lifetime at 500 cd/$m^2$ and recent progress in blue demonstrating efficiencies of 18 cd/A at 200 cd/$m^2$.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.4
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• pp.137-145
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• 1991

A universal joint is a connecting device of two hinges which can transmit torque from one shaft to another at fixed or at varying angles of intersection. It has been used properly not only as rotational but also as intermittent motion. For the particular kinematics condition of a universal joint, torsional and bending vibrations are produced excessively in an elastic driveline. In this paper only the torsional vibration behavior of a driveline with universal joints is analyzed numerically with the discrete model and a design method of the dynamic vibration damper is proposed, in order to reduce torsional vibrations especially in resonance region as a result of parametric variation.

• Journal of Families and Better Life
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• v.33 no.3
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• pp.49-66
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• 2015

The purpose of the study was to review literature on universal and residual services of early family-intervention. The review was focused on early family-intervention cases proven effective in empowering children, parents and families, which, in turn, brought about positive synergy effects to the community at large. Literature review was presented in the following order: first, the universal needs for early family-intervention; second, critical components and strategies of early family-intervention for successful outcomes; third, on-going international projects of early family-intervention, both universal and residual services, proven effective on a long-term basis. In conclusion, findings of the study were summarized and the theoretical, practical and political implications for Korean society were further discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.334-343
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• 2008

In this work we propose a universal pricing machine, which incorporates a universal pricing framework for the future IEEE802.16 WiMAX service with multiple classes of service. A multimedia service is provided by a QoS provisioning scheme in the WiMAX network and universal pricing means that it can compute the price for any type of service in a unified framework. In the proposed pricing framework we incorporate multiple types of services such as the real time and nonreal time services that are supposed to be provided in the WiMAX network. To that purpose, let us first carry out an analysis on the current pricing scheme of Korean WiMAX service which incorporates only the data size. From that analysis we propose a new pricing scheme for the future WiMAX service that provides different service classes in the network. Via numerical experiment, we verify the implication of the work.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.402-410
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• 2000

The current study examines principles to develop universal design guidelines for manufacturing information and communication devices. The study surveyed inconveniences disabled people experience in the information and communication environment with current technology and design, and suggested abbreviated universal design guidelines. Design guidelines should reduce those inconveniences detected through the task analysis and GOMS modelling of the usage by disabled people. Design and functional features of mobile phones were examined since they quickly became essential communication tools for both disabled and non-disabled people alike. Design issues were examined in controls, input methods, and output methods in terms of human factors and ergonomics. It is expected that both governments and manufacturers can save costs to produce and manufacture special assistive devices for disabled people by implementing universal design in their communication products. Since it is becoming the international trend, application of the universal design should be enforced to all communication and information devices by government for the higher quality of life for all groups of user.

• Journal of the Korean Mathematical Society
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• v.41 no.1
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• pp.65-76
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• 2004

An entire function $f\;{\in}\;H(\mathbb{C})$ is called universal with respect to translations if for any $g\;{\in}\;H(\mathbb{C}),\;R\;>\;0,\;and\;{\epsilon}\;>\;0$, there is $n\;{\in}\;{\mathbb{N}}$ such that $$\mid$f(z\;+\;n)\;-\;g(z)$\mid$\;<\;{\epsilon}$ whenever $$\mid$z$\mid$\;{\leq}\;R$. Similarly, it is universal with respect to differentiation if for any g, R, and $\epsilon$, there is n such that $$\mid$f^{(n)}(z)\;-\;g(z)$\mid$\;<\;{\epsilon}\;for\;$\mid$z$\mid$\;{\leq}\;R$. In this note, we review G. MacLane's proof of the existence of universal functions with respect to differentiation, and we give a simplified proof of G. D. Birkhoff's theorem showing the existence of universal functions with respect to translation. We also discuss Godefroy and Shapiro's extension of these results to convolution operators as well as some new, related results and problems.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.251-257
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• 2019

This paper presents the kinematic modeling of the human forearm rotation constructed with a spatial four-bar linkage. Especially, a circumduction of the distal ulna is modeled for a minimal displacement of the position of the hand during the forearm rotation from the supination to the pronation. To establish its model, four joint types of the four-bar linkage are, firstly, assigned with the reasonable grounds, and then the spatial linkage having the URUU (Universal-Revolute-Universal-Universal) joint type is proposed. Kinematic analysis is conducted to show the behavior of the distal radio-ulna as well as to evaluate the angular displacements of all the joints. From the simulation result, it is, finally, revealed that the URUU spatial linkage can be substituted for the URUR (Universal-Revolute-Universal-Revolute) spatial linkage by a kinematic constraint.

• Journal of Industrial Convergence
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• v.15 no.1
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• pp.1-7
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• 2017

The purpose of this study is to analyze the facility standards of the elderly welfare facilities applying the seven principles of the universal design. The facility standards of the elderly welfare facilities were limited to the provisions of the "Enforcement Regulation of the Elderly Welfare Act". There are few legal regulations applying the universal design in the construction of the elderly welfare facilities. The facility standards are set only with the minimum requirements such as securing the safety of the user, securing the space area, functional convenience, and risk prevention. However, the contents of the regulations are limited to the minimum standards for functional convenience and safety required for living. In conclusion, in the elderly welfare facilities, the notion of universal design, which considers not only the elderly, but also service providers, employees, and general visitors, should be considered.