• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2576-2581
• /
• 2003

We consider fault detection and isolation (FDI) problem for inertial navigation systems (INS) which use redundant inertial sensors and propose an FDI method using average of multiple parity vectors which reduce false alarm and wrong isolation, and improve correct isolation. We suggest optimal isolation threshold based on navigation performance, and suggest optimal sample number to obtain short detection time and to enhance detectability of faults little larger than threshold.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1998.04a
• /
• pp.147-154
• /
• 1998

The purpose of this paper is to propose the draft guidelines of seismic isolation design of Liquid Metal Reactor (LMR) using high damping laminated rubber bearings. The scopes of guidelines include design requirements of a seismically isolated system and components, seismic isolator, isolation system, interface system between seismic isolation and non-seismic isolation part, qualification and acceptance tests of seismic isolator, seismic isolation reliability, and seismic safety and monitoring system. Proposed guidelines shall be revised to extend to general design guideline for nuclear facilities by further research and discussions.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.10a
• /
• pp.465-472
• /
• 2000

Seismic isolation technique has been applied mainly in low rise buildings and its seismic performance was satisfactory during Kobe Earthquake. However, in the case of medium and/or high-rise buildings, mid-story isolation could be more technically feasible than base isolation to reduce earthquake forces. In this paper, the seismic effectiveness of mid-story isolation in medium and/or high-rise shear building as well as low rise shear building was evaluated analytically. After verifying the effectiveness of mid-story isolation technique, this method also applied in residential-commercial building. It was found that mid-story isolation, that is isolation between upper residential area and lower commercial area, could reduce inter-story drift and floor shear forces comparing to the conventional fixed base.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.76.1-76.1
• /
• 2010

Furnace를 이용한 $POCl_3$ 확산 공정은 실리콘 태양전지 제작과정에서 일반적으로 이용되는 에미터 층 형성 공정이다. 하지만, 확산 공정을 통해 P-N Junction을 형성할 경우 전면과 후면의 contact현상이 발생하게 되고 이를 제거하기 위해 Edge isolation 공정을 거치게 된다. 최근에는 레이저로 V 모양의 홈을 형성하는 방법이 이용되고 있다. 본 연구에서는 p-type 실리콘 웨이퍼 기판에 insulating barrier를 형성하여 edge isolation 공정을 없앤 Non-edge isolation공정을 제시한다. Non p-type 실리콘 웨이퍼에 insulating barrier를 형성한다. Insulating barrier가 형성된 BOE용액과 KOH에서의 견딤성 실험을 진행 하였다. 이후, p-type 단결정 실리콘 태양전지의 확산 공정을 진행하여 Non edge isolation 공정을 진행한 경우와 laser를 이용한 edge isolation 공정을 진행한 태양전지를 제작하여 특성을 비교하였다.

• Earthquakes and Structures
• /
• v.11 no.1
• /
• pp.25-43
• /
• 2016

The uneven distribution of rolling friction coefficient may lead to great uncertainty in the structural seismic isolation performance. This paper attempts to improve the isolation performance of a spring-damper-rolling isolation system by artificially making the uneven friction distribution to be concave. The rolling friction coefficient gradually increases when the isolator rolls away from the original position during an earthquake. After the spring-damper-rolling isolation system under different ground motions was calculated by a numerical analysis method, the system obtained more regular results than that of random uneven friction distributions. Results shows that the concave friction distribution can not only dissipate the earthquake energy, but also change the structural natural period. These functions improve the seismic isolation efficiency of the spring-damper-rolling isolation system in comparison with the random uneven distribution of rolling friction coefficient, and always lead to a relatively acceptable isolation state even if the actual earthquake significantly differs from the design earthquake.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.5
• /
• pp.1169-1181
• /
• 1994

Vibration isolation of mechanical systems, in general, is achieved through passive or active vibration isolators. Passive vibration isolator has an inherenrt performance limitation. Whereas, active vibration isolator provides significantly superior vibration-isolation performance at the cost of energy sources and sensors. Recently, in many cases, such as suspension system, precision machinery ... etc, active isolation system outweighs its limitation. Therefore, many studies, researches, and applications are carried out in this field. In this study, vibration-isolation characteristics of an active vibration control system using electromagnetic force actuator are investigated. Several control algorithms including optimal, feedforward are used for active vibration isolation. From the experimental results of each algorithm, effective control algorithms for this active vibration-isolation system are proposed.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.2
• /
• pp.124-131
• /
• 2002

This paper presents the design of an active vibration suppression controller for an air-spring type vibration isolation table. Firstly, isolation system model is constructed considering the isolation table, attached equipment and voice-coil actuator. An active control system is designed based on frequency-shaped sliding mode control theory rewarding high frequency uncertainties with respect to attached equipments on the isolation table. Finally. the performance of the active isolation system is evaluated by simulation under some disturbance conditions which are transmitted from base structure of the isolation system.

• Journal of Korean Association for Spatial Structures
• /
• v.14 no.2
• /
• pp.87-94
• /
• 2014

In this study, a smart isolation platform has been developed for control of microvibration of high-technology facilities, such as semi-conductor plants and TFT-LCD plants. Previously, microvibration control performance of a smart base isolation system has been investigated. This study compared microvibration control performance of a smart isolation platform with that of conventional base isolation and fixed base. For this purpose, train-induced ground acceleration is used for time history analysis. An MR damper was used to compose a smart isolation platform. A fuzzy logic controller was used as a control algorithm and it was optimized by a multi-objective genetic algorithm. Numerical analysis shows that a smart isolation platform can effectively control microvibration of a high-technology facility subjected to train-induced excitation compared with other models.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.11a
• /
• pp.425-430
• /
• 2000

This paper describes the effect of the pad stiffness on the noise reduction of impact noise isolation pads of a floor. And also a new semi-experimental method for measuring the impact noise isolation capability of a pad is introduced. The impact noise isolation pads made of wire-mesh, urethane-chip and foam rubber are used for measuring the stiffness, the vibrational insulation performance and the impact noise isolation capability. The correlation between the stiffness and impact noise isolation capability of pads is theoretically reviewed, and confirmed from the experimental results. For measuring the impact noise isolation capability of only an isolation pad, a semi-experimental method proposed in this study is more effective than the reverberation room method.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2006.03a
• /
• pp.417-423
• /
• 2006

The seismic characteristics with 3-Dimensional isolation systems have been studied using a shaking table system. In this study, we made nuclear power plant main control room floor systems and several seismic shaking table tests with and without isolation systems were conducted to evaluate floor isolation effectiveness. Isolation systems have showed large reduction effectiveness in acceleration and response spectra with x and z direction respectively, but horizontal isolation is more effective than vertical one It is required to make isolation systems of which design frequency is below 1Hz when applied to main control room of NPP, but considering much difficulties in making such isolation systems, it is recommended that much consideration should be taken into account when applied to main control room of NPP.