• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.633-643
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• 2005

An unmanned aerial vehicle (UAV) is an aircraft controlled by .emote commands from ground station and/o. pre-programmed onboard autopilot system. A navigation system in the UAV provides a navigation data for a flight control computer(FCC). The FCC requires accurate and reliable position, velocity and attitude information for guidance and control. This paper proposes an ADGPS/INS integrated navigation system for a UAV. The proposed navigation system comprises an attitude determination GPS (ADGPS) receive., a navigation computer unit, and a low-cost commercial MEMS inertial measurement unit(IMU). The navigation algorithm contains a fault detection and isolation (FDI) function fur integrity. In order to evaluate the performance of the proposed navigation system, two flight tests were preformed using a small aircraft. The first flight test was carried out to confirm fundamental operation of the proposed navigation system and to check the effectiveness of the FDI algorithm. In the second flight test, the navigation performance and the benefit of the GPS attitude information were checked in a high dynamic environment. The flight test results show that the proposed ADGPS/INS integrated navigation system gives a reliable performance even when anomalous GPS data is provided and better navigation performance than a conventional GPS/INS integration unit.

• Smart Structures and Systems
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• v.4 no.6
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• pp.779-794
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• 2008

Observer-based fault detection and isolation (FDI) filter design method is a model-based method. By carefully choosing the observer gain, the residual outputs can be projected onto different independent subspaces. Each subspace corresponds to the monitored structural element so that the projected residual will be nonzero when the associated structural element is damaged and zero when there is no damage. The key point of detection filter design is how to find an appropriate observer gain. This problem can be interpreted in a geometric framework and is found to be equivalent to the problem of finding a decentralized static output feedback gain. But, it is still a challenging task to find the decentralized controller by either analytical or numerical methods because its solution set is, generally, non-convex. In this paper, the concept of detection filter and iterative LMI technique for decentralized controller design are combined to develop an algorithm to compute the observer gain. It can be used to monitor structural element state: healthy or damaged. The simulation results show that the developed method can successfully identify structural damages.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.102-111
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• 2021

Maintainability is a major design parameter that includes availability as well as reliability in a RAM (reliability, availability, maintainability) analysis, and is an index that must be considered when developing a system. There is a lack of awareness of the importance of predicting and analyzing maintainability; therefore, it is dependent on past-experience data. To improve the utilization rate, maintainability must be managed as a key indicator to meet the user's requirements for failure maintenance time and to reduce life-cycle costs. To improve the maintainability-prediction accuracy in the detailed design stage, we present a maintainability-prediction method that applies Method B of the Military Standardization Handbook (MIL-HDBK-472) Procedure V, as well as a Korean maintainability-prediction software package that reflects the system complexity.

• Advances in concrete construction
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• v.9 no.1
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• pp.71-82
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• 2020

One of the most suitable methods in structural design is seismic separator. Lead-Rubber Bearing (LRB) is one of the most well-known separation systems which can be used in different types of structures. This system mitigates the earthquake acceleration prior to transferring to the structure efficiently. However, the performance of this system in concrete structures with different heights have not been evaluated thoroughly yet. This paper aims to evaluate the performance of LRB separation system in concrete structures with different heights. For this purpose, three, 16, and 23 story concrete structures are equipped by LRB and exposed to a far-field earthquake. Next, a time history analysis is conducted on each of the structures. Finally, the performance of the concrete structures is compared with each other in the term of their response to the earthquakes and the formation of plastic hinges. The results of the paper show that the rate of change in acceleration response and the ratio of drift along the height of 8 and 23 stories concrete structures are more than those of the 16-stories, and the use of LRB reduces the formation of plastic joints.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.146-146
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• 2017

현대의 스마트폰 및 태블릿pc등을 가능하게 만든 집적 기술 중의 하나는 3차원 집적 회로(3D-IC)와 같은 패키징 기술이다. 이러한 첨단 3차원 집적 기술은 메모리집적을 통한 대용량 메모리 모듈 개발뿐만 아니라, 메모리와 프로세서의 집적, high-end FPGA, Back side imaging (BSI) 센서 모듈, MEMS 센서와 ASIC 집적, High Bright (HB) LED 모듈 등에 적용되고 있다. 3D-IC의 3차원 모듈 제작 시에는 기존에 발생하지 않았던 여러 가지 파괴 모드들이 발생하고 있는데 Thermal/Photonic Emission 장비 등 기존의 2차원 결함분리 (Fault Isolation) 기술로는 첨단의 3차원 적층 제품들에서 발생하는 불량을 비파괴적으로 혹은 3차원적으로 분리하는 것이 불가능하므로, 비파괴 3차원 결함 분리 기술은 향후 선행 제품 적기 개발에 매우 필수적인 기술이다. 본 연구는 3D-IC 반도체의 비파괴적 내부결함 검사를 위하여 가시광선-근적외선 대역(351nm~1770nm)의 InGaAs (Indium Galium Arsenide) 계열 영상검출기 (imaging detector)를 사용하여 분광 시스템 광학 설계를 통한 초분광 영상 기반 검출 모듈을 제작하였다. 제작된 초분광 영상 기반 검출 모듈을 이용하여 구리 회로 위에 실리콘 웨이퍼가 3단 적층 된 반도체 더미 샘플의 초분광 영상을 촬영하였으며, 촬영된 초분광 영상에 대하여 Chemometrics model 기반의 분석기술을 적용하여 실리콘 웨이퍼 내부의 집적 구조에 대한 검사가 가능함을 확인하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.449-455
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• 2015

Built-In-Test(hereafter: BIT) is necessary functionality for aircraft flight safety and it requires a high failure detection capacity of more than 95 % in the case of avionics equipment. The BIT coverage analysis is needed to make sure that BIT meets its fault diagnosis capability. FMECA is used a lot of for the BIT coverage analysis. However, in this paper, the BIT coverage analysis based on electronic components is introduced to minimize the analytical error. Further, by applying the failure mode of the electronic components and excluding electronic components that do not affect flight safety, the BIT coverage analysis can be more accurate. Finally, BIT demo was performed and it was confirmed that the performance of the actual BIT matches the analysis of BIT performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.744-749
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• 2013

The protection switching technology is widely adopted in the fiber-optical transmission equipments based on TDM(Time Division Multiplexing), such as PDH, SDH/SONET. A variety of protection switching algorithms for Ethernet networks and the progress of standardization are summarized in the document. There are several kinds of protection switching algorithms for Ethernet networks, such as STP, RSTP, MSTP and etc. However, since Ethernet signal move through detour route, it causes much time to recover. Accordingly, it is difficult to secure a usability of Ethernet networks and QOS(Quality of Service). Also, if the protection switching protocol standardized by IEEE and ITU-T is used, it remains a inherent network switching time for protection. Therefore, a specific protection switching algorithm for Ethernet are needed for seamless and stable operation of Ethernet networks service for Distribution Automation System(DAS). A reliable protection algorithm with no switching delay time is very important to implement Self-healing service for DAS. This study of FPGA based protection switching algorithm for Ethernet networks shows that in case of faults occurrence on distribution power network, immediate fault isolation and restoration are conducted through interaction with distribution equipments using P2P(Peer to Peer) communication for protection coordination. It is concluded that FPGA based protection switching algorithm for Ethernet networks available 0ms switching time is crucial technology to secure reliability of DAS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.659-666
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• 2006

Servo-motors are used as key components of automated system by performing precise motion control as accurate positioning and accurate speed regulation in response to the commands from computers and sensors. Especially, the linear brushless servo-motors have numerous advantages over the rotary servo motors which have connection with the friction induced transfer mechanism such as ball screws, timing belts, rack/pinion. This paper proposes an estimation method of unknown motor system parameters using the informations from the sinusoidal driving type linear brushless DC motor dynamics and outputs. The estimated parameters can be used to tune the controller gain and a disturbance observer. In order to meet this purpose high performance Digital Signal Processor, TMS320F240, designed originally for implementation of a Field Oriented Control(FOC) technology is adopted as a controller of the liner BLDC servo motor. Having A/D converters, PWM generators, rich I/O port internally, this servo motor application specific DSP play an important role in servo motor controller. This linear BLDC servo motor system also contains IPM(Intelligent Power Module) driver and hail sensor type current sensor module, photocoupler module for isolation of gate signals and fault signals.

• The Korean Society of Law and Medicine
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• v.16 no.2
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• pp.197-225
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• 2015

The presentation of this paper was triggered by the spread of MERS in Korea in the year 2015. The analysis of the present acts related with MERS is necessary in order to cope efficiently with any probable spread of such infectious diseases as MERS in future. The acts that should be analyzed in this paper include 'Medical Service Act' and 'Infectious Disease Control And Prevention Act' (hereafter, IDCAPA). At first the classification of the infectious diseases in IDCAPA should be referred to. The Act does not properly classify them because the scope of concept of each group of the infectious diseases overlaps each other. This overlap should be removed. The present system in IDCAPA is not proper for the efficient notification and reporting of the infectious disease patients. This is so in some viewpoints including the persons obligated to make the notification and reporting, the persons to whom they should notify and report such patients, and the process of notification and reporting. The efficient approach to the information related with the infectious disease is necessary for the rapid prevention of its spread. Cohort isolation and quarantine of the infectious patients and exposed contacts are the strongest and most efficient steps for the prevention of spread of the infectious diseases. One of the great problems related with such steps would be the conflict of powers or attributions, the likelihood of which is inevitable under the present system of IDCAPA. The IDCAPA distributed the power or attribution to take the steps to the three governments including the central government, the metropolitan government and the primary local government. The power should be concentrated in the central government, which could afford financially to compensate for the huge amount of damages caused likely by the steps. The power to take the steps would be actually just a useless thing for its holder without such financial capacity. The remedy for the victims by the fault of spreader should be approached to in the sense of national wealth. The general principle of tort law could not supply the victims with the sufficient remedy because the damages would be likely too huge for the wealth of such spreader to cope with. In future another parliamentary inspection could reveal another problems in the administration by the government of the MERS event in the year 2015. Any problem caused by defect in the legal system of the control and prevention of the infectious diseases should be taken into consideration when the legal system would be reformed in future.