• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.3
• /
• pp.65-74
• /
• 2019

This study presents the optimal isolation period according to the number of vertically expended stories in order to provide the basic data for the application of the seismic isolation system in the vertically expended remodeling of the aged apartment. As a result of the structural analysis, the isolation period should be at least twice the primary structure in three-story vertical expansion, three times in two-story expansion, and four times in one-story expansion for the effective application of the isolation system. On the basis of the result, the efficacy of an isolation system for the actual apartment structure, which is three-story vertically expended, was analytically verified. The maximal acceleration response on the top floor reduced by 70% and 65% of the non-isolated structure in the X and Y directions respectively. Additionally, the base shear force decreased by 30% in the both directions, compared to the non-isolated structure.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.6
• /
• pp.597-605
• /
• 2008

The feasibility study of a newly proposed smart base isolation system employing magneto-rheological elastomers(MREs) has been carried out. MREs belong to a class of smart materials whose elastic modulus or stiffness can be adjusted by varying the magnitude of the magnetic field. The base isolation systems are considered as one of the most effective devices for vibration mitigation of civil engineering structures such as bridges and buildings in the event of earthquakes. The proposed base isolation system strives to enhance the performance of the conventional base isolation system by improving the robustness of the system wide stiffness range controllable of MREs, which improves the adaptability and helps in better vibration control. To validate the effectiveness of the MRE-based isolation system, an extensive numerical simulation study has been performed using both single-story and five-story building structures employing base isolated devices under several historical earthquake excitations. The results show that the proposed system outperformed the conventional system in reducing the responses of the structure in all the seismic excitations considered in the study.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.841-842
• /
• 1988

For determination of black-out area and restoration area by an expert system for fault section estimation and power system restoration using information from circuit breakers, it is necessary that the recognition of system isolation state and a method of finding the change of system isolation state by the state transition of breakers in isolated system. This paper presents a method of resolving the above problem by rule-based approach.

• Journal of Korean Association for Spatial Structures
• /
• v.18 no.1
• /
• pp.55-65
• /
• 2018

In order to reduce the seismic response of the spatial structure, a seismic isolation system with sufficient flexibility is used. The natural period of structure with seismic isolation system got be long to avoid prominent period. In this study, The seismic response of the truss-arch structure, which is modeled in three types according to the rise-span ratio is analyzed on El-centro, Northridge and Artificial Earthquake and compared with the seismic response of the truss-arch structure with lead rubber bearing(LRB). When seismic load is applied to the truss arch with isolation system, the horizontal acceleration response of the truss arch is reduced and vertical seismic response is also reduced. The application of the seismic isolation system is effective in controlling the seismic response.

• Journal of the Optical Society of Korea
• /
• v.17 no.1
• /
• pp.103-108
• /
• 2013

The operation of a Doppler wind LIDAR in a mobile environment is very sensitive to shocks and vibrations, which can cause critical failures such as misalignment of the optical path and damage to optical components. To be able to stabilize the LIDAR and to perform wind field measurements in motion, a shock absorption and vibration isolation system was designed and implemented. The performance of the vehicle-mounted Doppler wind LIDAR was tested in motion, first in a circular test route with a diameter of about 30 m and later in regular expressway traffic. The vibration isolation efficiency of the system was found to be higher than 82% in the main vibration area and shock dynamic deflection was smaller than maximal deflection of the isolator. The stability of the laser locking frequency in the same mobile environment before and after the vibration isolation system installation was also found to be greatly improved. The reliability of the vibration isolation system was confirmed by good results of the analysis of the LIDAR data, in particular the plane position indicator of the line of sight velocity and the wind profile.

• Earthquakes and Structures
• /
• v.16 no.6
• /
• pp.743-755
• /
• 2019

In this paper, a new system of seismic isolation for buildings - called suspended columns - is introduced. In this method, the building columns are placed on the hinged cradle seats instead of direct connection to the foundation. In this system, each of the columns is put on a seat hung from its surrounding area by a number of cables, for which cavities are created inside the foundation around the columns. Inside these cavities, the tensile cables are hung. Because of the flexibility of the cables, the suspended seats vibrate during an earthquake and as a result, there is less acceleration in the structure than the foundation. A Matlab code was written to analyze and investigate the response of the system against the earthquake excitations. The findings showed that if this system is used in a building, it results in a significant reduction in the acceleration applied to the structure. A shear key system was used to control the structure for service and lateral weak loads. Moreover, the effect of vertical acceleration on the seismic behavior of the system was also investigated. Effect of the earthquake characteristic period on the system performance was studied and the optimum length of the suspension cables for a variety of the period ranges was suggested. In addition, measures have been taken for long-term functioning of the system and some practical feasibility features were also discussed. Finally, the advantages and limitations of the system were discussed and compared with the other common methods of seismic isolation.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.4
• /
• pp.1-8
• /
• 2017

In this paper, we propose a fault isolation system for device drivers of the Linux operating system. High availability systems impose stringent requirements upon Linux operating system. Especially device drivers can be a major source of operating system instability and many times contribute to system degradation and outages. The proposed fault isolation system identifies the occurrence of the memory-related faults in device driver and isolates it from the kernel. By operating at the early stage of the page fault handler in Linux kernel, the system detects which module causes fault and isolates it transparently from the remaining part of the kernel. By experiments, we show that the proposed system efficiently detects faults incurred by device driver, isolates the device driver and the process which accessed the driver module from the kernel.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.2
• /
• pp.53-59
• /
• 2005

In this study, the isolation system for multi-mechanism HIF (high impulsive force) device has been investigated. For this purpose, parameter optimization process has been performed based on the simplified isolation system model under constraints of moving displacement and transmitted force. The design parameters for multi-mechanism HIF device have been derived with respect to HIF system I and HIF system II, respectively. In order to implement the dynamic absorbing system, the dual stage hydro-pneumatic damper and magnetorheological damper with semi-active control scheme are considered. Finally, the performance of the designed prototype isolation system has been evaluated by experimental works under actual operating conditions.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.7 s.124
• /
• pp.565-571
• /
• 2007

In the process of accurate manufacture and measurement, it is necessarily required to isolate external or internal vibration due to external disturbance and internal actuators. The higher vibration isolation system gets damping around resonance, the better it is generally. This paper analyzes the performance of an existing passive air-spring for vibration isolation table by using experiment and simulation. Optimal design for a passive air spring can be obtained by tuning the size of the orifice. Also design for an active isolation system is carried out by applying PID controller and considering non-linearity of pneumatic characteristics with help of look-up table. We have developed the active vibration isolation table with the better isolation performance.

• International Journal of High-Rise Buildings
• /
• v.7 no.3
• /
• pp.233-242
• /
• 2018

Since the response reduction effect on over 200-meter-tall resulting from the seismic isolation system is smaller in general than low-rise and mid-rise buildings, mid-story isolated buildings are considered to reduce the response in the upper part above the isolation story, however, in many cases, the acceleration response just below the isolation story is likely to be the largest. This paper presents the structural design schemes, the design of the main structural frames, and the constructions of a 230-meter-tall super high-rise building with mid-story isolation mechanism integrated in Roppongi, Tokyo. Moreover, this paper shows how the architectural and structural design for integrating a mid-story isolation system in a super high-rise building has been conducted and what solutions have been derived in this project. The realization of this building indicates new possibilities for mid-story isolation design for super high-rise buildings.