• 한국자동차공학회논문집
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• 제14권5호
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• pp.1-8
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• 2006

The Steer-By-Wire(SBW) system replaces complex mechanical linkages of the current steering system with electric motors, sensors, and electronic control units. However, the SBW system should guarantee its safety and reliability before commercialization, and therefore, a reliable and robust fault-tolerant technology has to be implemented. This paper proposes a fault-tolerant control algorithm for the SBW system. Based on careful analysis on propagation effects of sensor faults, a reliable fault-tolerant control strategy has been developed. The fault-tolerant controller consists of a fault detection part that monitors and detects faults in the steering wheel and road wheel sensors, and a reconfiguration part that switches to normal sensor signal based on fault detection information. It has been demonstrated by simulation that the proposed algorithm detects sensor faults accurately and enables reliable steering control under various dynamic fault situations.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.94-100
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• 2011

TCMS is the most important controller in the subway train for reliable train control and service oriented flexibility. TCMS software charges communications and control of train and maintains control devices so we use QNX for real-time control. This paper introduces overall software development of TCMS using various diagrams. Software implementation details in TC and CC are explained using deployment diagram through train configuration. Driving control process among many processes is focused to present implement details which controls train by driver or automatic train operation and handles commands to control deriving devices in cars. Reliable operation of train and easy maintenance process is achieved through the same hardware in train control computer and car control computer.

• 전기학회논문지
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• 제63권7호
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• pp.976-986
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• 2014

In this paper, the problem of reliable control of linear systems with time-varying delays, randomly occurring disturbances, and actuator failures is investigated. It is assumed that actuator failures occur when disturbances affect to the systems. Firstly, by using a suitable Lyapunov-Krasovskii functional and some recent techniques such as Wirtinger-based integral inequality and reciprocally convex approach, stabilization criterion for nominal systems with time-varying delays is derived. Secondly, the proposed method is extended to the reliable $H_{\infty}$ controller design for linear dynamic systems with time-varying delays, randomly occurring disturbances, and actuator failures. Since nonlinear matrix inequalities (NLMIs) are involved in proposed results, the cone complementarity algorithm will be introduced. Finally, two numerical examples are included to show the effectiveness of the proposed criteria.

• 한국정보통신학회논문지
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• 제19권4호
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• pp.787-793
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• 2015

브로드밴드 무선 접속 (Broadband Wireless Access) 네트워크에서 신뢰성 있는 멀티캐스트 서비스는 자동 재전송 요구 (automatic repeat request, ARQ) 방식에 기반한 패킷 수신 정보 알림을 필요로 한다. 따라서, medium access control (MAC) 계층에서 신뢰성 있는 멀티캐스트 서비스를 지원하기 위해서, 본 논문에서는 스프레딩 코드(Cumulative ACK 코드와 ARQ Feedback Request 코드) 기반 멀티캐스트 피드백 기법을 제안한다. 본 논문에서는 무선채널 환경에 대한 패킷 에러율 (packet error rate, PER) 분석을 기반으로, 다양한 무선채널 환경 변화에 대하여 유니캐스트 ARQ 피드백 메시지를 사용하는 기존 방안 대비 제안 방안이 요구되는 상향링크 자원의 양에서 매우 우수한 특성을 가짐을 확인할 수 있다.

• 전기학회논문지
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• 제57권11호
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• pp.2001-2005
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• 2008

This paper presents a design of a simulation apparatus to evaluate an operational control algorithm for the PRT system. PRT systems require very short headways to increase the line capacity and a very reliable vehicle control algorithm for avoidance of the impact between vehicles. Therefore, it can be said that the development of an reliable operational control algorithm for the PRT systems is much more important than that of the hardware configurations. In this paper an apparatus is proposed which is composed of virtual vehicles, a central control system, a man-machine interface and monitoring device, making it possible for the designed operational control algorithm to be implemented and tested. For the test of the proposed apparatus a test operational control algorithm is designed and the experimental results show the effectiveness of the proposed simulation apparatus for test and evaluation of the PRT operational control algorithms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.731-733
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• 1999

Distributed Control System has been used for large scale and critical system control such as aerospace industries, chemical and power plant and so on. It is very impotant factors for design of the control system to be reliable and fault-tolerant. These control systems have backup or redundant processing modules for minimizing the time of failure and improving reliability. But such methods have changeover duration from faulty module to healthy one. During that interval, feedback control loop raises bumper and performance of the system become worse. TMR(Triple Modular Redundancy) control system is one of the best reliable ones that can overcome such a mortal drawback. This paper analyzes the components of TMR system functionally and proposes practical and cost effective configuration method for turbine control of thermal power plant.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.551-555
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• 1996

The continuing demand for quality products requires better understanding and improved control of the production process. And, in recent year requirements for flatness control in strip rolling have become increasinglysevere because of the control for flatness of cold rolled strip is essential for further down stream processing. Also a speeds of rolling mills to meet productivity requirements puts a demanding requirement on the control of flatness of rolled strip. The demands on a total flatness control system therefore are a measuring and indication system consisting of a measuring roll that is robust, accurate, reliable and require a minimum of maintenance. The critical prt of any control system is the quality of the information being provided by the measurement instrument or device. It is therfore of utmost importance to have an accurate, repeatable and reliable measuring system. So, in this paper, The measuring roll for automatic flatness control system of contact type has been investigated.

• 제어로봇시스템학회논문지
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• 제13권3호
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• pp.230-234
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• 2007

Generally, huge amounts of data traffic are generated by using broadcasting method to deliver sensing data to a sink node reliably so that it makes a severe network saturation problem resulting in unreliable data transfer. In order to handle this problem, a new congestion control protocol is required for supporting reliable data transfer, minimal use of energy and network resources at the same time in wireless sensor networks. In this paper, it proposes a Protocol to guarantee both a reliable transfer in data accuracy and minimum consumption of energy waste by using Hop-by-Hop sequence number and DSbACK(Delayed and Selective ACK Buffer Condition) scheme. In addition, it proves that reliability and energy efficiency are enhanced by the proposed method with the simulation results performed on TinyOS platform which is a component based built-in OS announced by UC Berkely with the performance comparison of other existing methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.40.2-40
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• 2001

The protection system of the system communication, nuclear reactor and chemical reactor are representative of reliable system. This reliable system must be designed based on reliability as well as concept of safety, which is a failed system go a way of safe. Reliable system is composed of part of data acquisition, calculator, communication with redundancy, and a voter is important factor of reliability. Because it is serially connected. This paper presents a Design and Analysis of a Voting Mechanism considering Safety for reliable system Using EPLD. In the case of digital implementation a coincidence logic (voter) of reliable system, it needs CPU and memory, so increase a number of units. Therefore the failure rate and cost are increased on contrary when it is designed EPLD or FPGA.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.275-290
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• 2014

In this paper, Simple Adaptive Control (SAC) method is used to mitigate the detrimental effects of earthquakes on MR-damper equipped structures. Acceleration Feedback (AF) is utilized since measuring the acceleration response of structures is known to be reliable and inexpensive. The SAC is simple, fast and as an adaptive control scheme, is immune against the effects of plant and environmental uncertainties. In the present study, in order to translate the desired control force into an applicable MR damper command voltage, a neural network inverse model is trained, validated and used through the simulations. The effectiveness of the proposed AF-based SAC control system is compared with optimal H2/LQG controllers through numerical investigation of a three-story model building. The results indicate that the SAC controller is substantially effective and reliable in both undamaged and damaged structural states, specifically in reducing acceleration responses of seismically excited buildings.