• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.55-66
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• 2005

The effectiveness of fuzzy supervisory control technique for the control of seismic responses of smart base isolation system is investigated in this study. To this end, first generation base isolated building benchmark problem is employed for the numerical simulation. The benchmark structure under consideration is an eight-story base isolated building having irregular plan and is equipped with low-damping elastometric bearings and magnetorheological (MR) dampers for seismic protection. Lower level fuzzy logic controllers (FLC) for far-fault or near-fault earthquakes are developed in order to effectively control base isolated building using multi-objective genetic algorithm. Four objectives, i.e. reduction of peak structural acceleration, peak base drift, RMS structural acceleration and RMS base drift, are used in multi-objective optimization process. When earthquakes are applied to benchmark building, each of low level FLCs provides different command voltage and supervisory fuzzy controller combines two command voltages io one based on fuzzy inference system in real time. Results from the numerical simulations demonstrate that base drift as well as superstructure responses can be effectively reduced using the proposed supervisory fuzzy control technique.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.11
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• pp.943-951
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• 2015

Inertial sensors are important components of navigation system whose performance and reliability can be improved by specific sensor arrangement configuration. For the reliability of the system, Fault Detection and Isolation (FDI) is conducted by comparing each signal of arranged sensors and many arrangement configuration were suggested to optimize FDI performance of the system. In this paper, multiple conic configuration is suggested with optimal navigation condition and its FDI performance is analyzed by established Figure Of Merit (FOM) under the condition for navigation optimality. From FOM comparison, the multiple conic configuration is superior to former one in point of FDI.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.179-187
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• 2004

We consider some problems of the Modified SPRT(Sequential Probability Ratio Test) method for fault detection and isolation of inertial redundant sensor systems and propose an Advanced SPRT method which solves the problems of the Modified SPRT method. The problems of the Modified SPRT method to apply to inertial sensor system come from the effect of inertial sensor errors and the correlation of parity vector components. We use a two-stage Kalman filter to remove effects of the inertial sensor errors and propose the modified parity vector and the controlled parity vector which reduces the effect of correlation of parity vector components. The Advanced SPRT method is derived form the modified parity vector and the controlled party vector. Some simulation results are presented to show the usefulness of the Advanced SPRT method to redundant inertial sensor systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.40-51
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• 2009

To analyze influences under open faults in switching devices of the PWM inverter and under the isolation between the inverter and motor terminal, a faulty model for the inverter-driven permanent magnet synchronous motor is presented. Even though the conventional dq motor model obtained through the transformation of phase voltage model is widely used to analyze and control AC motor, it can not be used under open faults in switching devices since the 3-phase balanced condition is no longer hold under the open fault and it is not easy to obtain motor input voltages in open phase from the pole voltage. To deal with this problem, a faulty model for an inverter-driven permanent magnet synchronous motor is derived by using the line voltage of motor according to switch open, which can be effectively used for performance evaluation of the diagnostic algorithm. The validity of the proposed faulty model is verified through comparative simulations and experiments using DSP TMS320F28335.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.37-43
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• 2018

A developer solves problems with isolating failures if faults are detected when inspecting missiles using the missile assembly test set (MATS) and then resumes the testing. In order to identify faults, it is necessary to analyze the data coming from the equipment, but the information received may not be sufficient, depending on the inspection environment. In this case, the developer repeats the test until the problem is reproduced or checks the performance of each piece of equipment that is related to the fault. When this task is added, schedule management becomes problematic, and development costs rise. To solve this problem, we need to design a MATS in a systematic way to increase fault coverage while satisfying the required reliability. By designing the necessary processes for each procedure, it is possible to reduce the fault identification time when a fault is detected during operations. But it is not possible to guarantee 100% fault coverage, so we provide another method by comparing costs and effects. This paper describes a development method to enhance the reliability of the missile assembly test set; it describes the expected effects when it is adapted, and describes the limitations of this method.

• Journal of Applied Reliability
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• v.12 no.2
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• pp.105-119
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• 2012

In this paper, we have proposed a methodology which can make effective test for system integration of complex guided missile system. System integration test play a significant role in the development of weapon system, providing the means to detect and isolate faults on first linkage between sub-systems. Integration tests for domestic weapon system has executed not a technology-intensive method based on tool but labor-intensive method based on experience. Higher cost, longer period, and more resource are required to execute system integration test for complex guided missile system comparing with past weapon systems, because recently weapon systems have more complex and more networked functions. Because the proposed design method for system integration test decreases number of test case, it lead to a decrease of cost, period, and resource for integration test of weapon system. The proposed configuration for system integration test will ensure reliability through detection and isolation of fault on linkage between sub-systems.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.1
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• pp.1-8
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• 2003

In this paper, a reconfigurable flight control system is designed by applying the sliding mode control scheme. The sliding mode control method is a nonlinear control method which has been widely used because of its merits such as robustness and flexibility. In the sliding mode controller design, the signum function is usually included, but it causes the undesirable chattering problem. The chattering phenomenon can be avoided by using the saturation function instead of signum function. However, the boundary layer of the sliding surface should be carefully treated because of the use of the saturation function. In contrast to the conventional approaches, the thickness of the boundary layer of our approach does not need to be small. The reachability to the boundary layer is guaranteed by the sliding mode controller. The fault detection and isolation process is operated based on a sliding mode observer. To evaluate the reconfiguration performance, a numerical simulation using six degree-of-freedom aircraft dynamics is performed.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.13-21
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• 2018

Technology trends of onboard and ground health management system software for aircraft gas turbine engines are surveyed. The software has changed from ground based software for fault detection and identification to a model based health identification technology for onboard software. This advanced algorithm is currently under development in a technically advanced country while domestic research is on the birth stage. This paper suggested that the optimal development plan of the software considering current technology state.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.570-576
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• 2010

This paper can be used for GPS air navigation study on integrity monitoring algorithm as, the projected horizontal plane using GPS pseudorange residuals for fault detection satellites were suspected. Failure to remove the detected suspicious satellite, compare with threshold which is calculated using satellite deployment (PDOP) and determine whether the failure is presented. The theory that horizontal projection of the satellite failure residuals greater than residual of normal satellite is proved mathematically. Comparison with horizontal projection residuals are likely to malfunction in the satellite were presented. To evaluate the proposed algorithm, bias fault insert into GPS pseudorange, and compare with conventional parity space method about fault detection and isolation capability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.218-226
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• 2017

In this paper, optical transport network in real time monitoring system using smart phone. The existing housing using monitoring was a smart phone of optical transport network access switch about an event with new installation of cognitive system in real time. This paper can this problem to be solved of the invention in real time maintenance using smart phone application and optical cable closure switch. If you want to find optical cable closure fault location, this smart phone web is very useful. Cable tie is isolation of fiber spare board from fiber switch tie occur push message. Housing and access, and an external failures otdr the measurement of the global positioning to be able to easily using the This paper can find event of optical cable closure unauthorized work and fault using smart phone OTDR function. the optical cable fault time reduction and network transport quality by managing real time optical cable section by using the smart phone can be maintained efficiently.