• Journal of the Korean Data and Information Science Society
• /
• v.7 no.1
• /
• pp.87-92
• /
• 1996

A regression model with nested erroe structure is considered. The regression model includes two error terms that are independent and normally distributed with zero means and constant variances. This error structure of the model gives correlated response variables. The distributions of variance components in the regression model with nested error structure are dervied by using theorems for quadratic forms.

• Proceedings of the KIEE Conference
• /
• 2007.10c
• /
• pp.180-181
• /
• 2007

농업 분야 시장개방이 확대되고 농업에 종사하는 연령의 고령화로 인해 농 기계류의 자동화는 수요자의 요구와 함께 최우선적으로 해결되어야 할 과제로 꼽히고 있으며, 극한의 환경에서 원활하게 작동되는 자동화 시스템의 필요성이 대두되고 있다. 본 논문에서는 농기계류 중에서 현장에서 널리 쓰이는 릴 방제기의 원격 제어 장치의 개발로서 작업 2km 반경 내에서 원격제어를 할 수 있는 자동 제어기능의 릴 방제기에 개발에 관한 연구이다.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.336-338
• /
• 2006

Motorized retractors enhance the safety of passengers by removing the slack of webbing and by holding upright driving position. Reliability of a driving mechanism that includes one-way clutch between the driving motor and webbing is directly linked to the safety of passenger. In this research, conditions for locking one-way clutch and also conditions for sustaining locking are theoretically investigated. the operation of a motorized retractor under realistic conditions is simulated in order to validate the proposed retractor design.

• Electronics and Telecommunications Trends
• /
• v.35 no.5
• /
• pp.57-68
• /
• 2020

This paper reviews the recent trends in optical access technologies and their future directions. As the number of hyper-connected, ultra-low-latency, and hyper-realistic services increases, the wireless path has become shorter and the optical access network has become deeply penetrated into the end user. The optical access network continues to evolve through endless innovation via high-speed, ultra-low-latency, and abstraction/virtualization technologies.

• The Bulletin of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.54.1-54.1
• /
• 2007

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.365-368
• /
• 2006

In this paper, the post cracking stress-crack width relationship of the composite is studied from a micromechanics points of view. Cook-Gordon debonding effect is studied by more refined method with considering of chemical friction of fiber interface. As a result, fiber with pre-debonding length retards stress development and shows more wide crack width for the same force level. longer pre-debonding length and lower pre-debonding bond strength results in lower full-debonding force, but same crack width.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.55.4-55
• /
• 2002

In the semiconductor fabrication, particle contamination is wide-spread and one of major causes to yield loss. Extensive testing has revealed that even careful handling of wafers during processing may cause photo-resist materials to flake off wafer edges. So, to remove the photo-resist at the outer 5mm of wafers, UV(Ultraviolet) rays are exposed. WEE (Wafer Edge Exposure) process station is the system that exposes the wafer edge as prespecified by controlling the positioning mechanism and maintaining the light intensity level In this work, WEE process station has been designed so as to significantly lower the amount of particle contamination which occurs even during the most r...

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.372.1-372
• /
• 2002

Although impact hammer is widely used as a convenient excitation tool in structural modal testing, little is known about the dynamic charateristics of its impulse mechanism. Transmission of the impulsive force to the structure depends on the dynamic properties of the impact hammer as well as the stiffness of the tip. An improved dynamic model of the impact hammer is proposed in this study with numerical simulations based on this model. (omitted)

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1631-1638
• /
• 2007

In this paper, a modeling for the dynamic behavior of a train vehicle is suggested for the prediction of the braking characteristics. In the dynamic modeling, effects of the primary and secondary suspension elements are considered and interactions between two vehicles are also estimated. This study can offer some fundamental results for a further research to enhance the braking performance using active braking control.

• Proceedings of the KSMRM Conference
• /
• 1997.10a
• /
• pp.55-55
• /
• 1997