• Journal of Information Display
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• v.7 no.1
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• pp.7-11
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• 2006

In this paper, we report the fabrication of high quality polymer walls by using a monomer containing fluorine (F-monomer). Polymer walls with no phase retardation were fabricated by using photo-polymerization induced anisotropic phase separation of the mixture composed of liquid crystal (LC) and F-monomer. Thanks to the immiscibility of fluoride, we could form high quality polymer walls with no light leakage. We measured electro-optic characteristics of a twisted-nematic (TN) LC cell whose polymer walls were fabricated by using the F-monomer, and the measurements were compared with that fabricated by using the monomer without fluorine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.574-577
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• 2004

A coupler is a microwave passive component used for power coupling or dividing. Regarding the trend of current telecommunication systems it is highly desirable for monolithic integration of passive components as such LTCC(Low temperature cofired ceramics) technology offers potential advantage in size, cost and performance. Utilizing LTCC technology a 2012 size type dual band coupler for DCS and EGSM band was fabricated. Its characteristics such as coupling, insertion loss, isolation and directivity was measured and compared with simulation results

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.392-395
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• 2004

A coupler is a microwave passive component used for power coupling or dividing. Regarding the trend of current telecommunication systems it is highly desirable for monolithic integration of passive components as such LTCC(Low temperature cofired ceramics) technology offers potential advantage in size, cost and performance. Utilizing LTCC technology a 1608 size type dual band coupler for DCS and EGSM band was fabricated. Its characteristics such as coupling, insertion loss, isolation and directivity was measured and compared with simulation results.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.331-332
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• 2008

A horn antenna having dual-band and dualpolarization operation is proposed. To implement a small-sized structure providing circular polarizations in the Ka- and K-band, the antenna is designed by using the horn radiator on the basis of a conical helix which is exited by two ports for TX and RX in both ends. Through a design optimization process, a compactdual-band and dual-polarized horn antenna having high gain and high isolation performance was realized.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.10 s.103
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• pp.1160-1168
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• 2005

Floor impact noise isolation performance of reinforced concrete floors was investigated through new measurement method using impact bail. Strong impact force in Bow frequency band below 63 Hz of bang machine is not similar to human impact source and causes some problem in evaluating heavy-weight Impact noise but heavy-weight impact noise measurement and evaluation using impact ball which is very similar to human impact is more reliable than bang machine. Correction value on the background noise and sensitivity of residents should be considered on the floor impact noise evaluation classes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1185-1191
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• 2001

This paper discusses an experimental method for measuring the insertion loss (IL) performance of multi-layered insulations that are used in vehicles. Instead of two adjacent reverberation chambers which are generally used to measure the transmission loss (TL) of the large sound isolation materials, air-borne sound insulation tester was utilized to determine the IL and articulation index (AI) of standardized insulation materials. In comparison to reverberation chamber method, air-borne sound insulation tester method is more space-saving, more time-saving and more simple to the automotive acoustics. From the empirical results, it is found that the performances of insulation materials are closely connected with density of polyurethane foam, thickness of heavy layer, thickness of polyurethane foam, and application ratio to panel area.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.5
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• pp.259-265
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• 2016

In this paper, we present an architecture for the fault isolation by applying virtualization-based multi-stack technologies. We propose the simultaneous sharing and switching mechanism using virtualied serial communications. Each guest OS has its own virtual serial device. The distribution module provides communications between the guest OS's through the virtual serial devices and simultaneously detect the liveness of the guest OS. The suggested mechanism has been implemented in VirtualBox and shows satisfactory performance in transmission speed and data sharing capability with virtual RS232.

• Advances in Traditional Medicine
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• v.3 no.2
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• pp.63-71
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• 2003

The psycho-pharmacological effect of BRHAT VATACHINTAMANI RASA (BVC) an Ayurvedic preparation was investigated, both in animal and clinical models. It was observed that BVC possess a sedative or quitening effect in that it significantly decreased the spontaneous motor activity, and also lowered the exploratory behavior of the amphetamine treated animals. This was further evident by increase in climbing out time and taming effect on animal in isolation induced aggression test. Apart from very high dose it seems have little effect on pentobarbital sleeping time and narcotic analgesic test. The drug BVC increases performance of the animal in forced locomotor test. The effect of VATACHINTAMANI RASA on clinical study was not significant.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.4
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• pp.254-260
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• 2000

This paper deals with the development of fault tolerant control for a nonlinear boiler system with noise and disturbance. The MCMBPC(Multivariable Constrained Model Based Predictive Control) is adopted for the control of the specific boiler turbin model. The fault detection and diagnosis are accomplished with the Kalman filter and two bias estimators. Once a fault is detected, two Bias estimators are driven to estimate the fault and to discriminate Process fault and sensor fault. In this paper, a fault tolerant control scheme combining MCMBPC with a fault compensation method based on the bias estimator is proposed. The proposed scheme has been applied to the nonlinear boiler system and shown a satisfactory performance through some simulations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.427-439
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• 2003

A previous study evaluated the seismic response of typical multi-span simply supported (MSSS) and multi-span continuous (MSC) steel-girder bridges in the central and southeastern United States. The results showed that the bridges were vulnerable to damage resulting from impact between decks, and large ductility demands on nonductile columns. Furthermore, fixed and expansion bearings were likely to fail during strong ground motion. In this paper, several retrofit measures to improve the seismic performance of typical multi-span simply supported and multi-span continuous steel girder bridges are evaluated, including the use of elastomeric bearings, lead-rubber bearings, and restrainer cables. It is determined that lead-rubber bearings are the most effective retrofit measure for reducing the seismic vulnerability of typical bridges. While isolation provided by elastomeric bearings limits the forces into the columns, the added flexibility results in pounding between decks in the MSSS steel-girder bridge. Restrainer cables, which are becoming a common retrofit measure, are only moderately effective in reducing the seismic vulnerability of MSSS and MSC steel girder bridges.