• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.345-349
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• 1991

The accurate simulation of the static and/or dynamic response of a power system requires detailed knowledge of the behavior of the loads. For the Precise load model, the chearacteristics and the composition of the load are needed. In this papers, the reliable estimation method of load composition is suggested intruducing knowledge-based system though it used various weekly-reliable survey data.

• Journal of Electrical Engineering and Technology
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• 제2권3호
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• pp.379-385
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• 2007

Recently, vital devices of the railway signaling systems have been computerized in order to ensure safe train operation. Due to this computerization, we have gradually come to need networking interfaces between these devices. Thus it is important that there be reliable communication links in the signaling systems. Network technologies are applied in the real-time industrial control system, and there are numerous studies to be carried out on the computer network technology for vital control systems such as railway signaling systems. For deploying the studies, we consider costs, reliability, safety assurance technique, compatibility, and etc. In this paper, we propose the Ethernet for railway signaling systems and also precisely describe the computer network characteristics of vital railway signaling systems. Then we demonstrate the experimental results of the proposed network algorithm, which is based on switched Ethernet technology with redundancy scheme.

• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.53-63
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• 2016

This paper applies WiMedia UWB network into a wireless ship area network (WSAN) so as to support high-quality multimedia services on board and reliable instrument control information as well, since the need for mixed high-quality video traffic and shipboard control data traffic is essential for a high-cost valued digital ship. Thus, in this paper, prioritized contention access (PCA) and distributed reservation protocol (DRP) based on WiMedia UWB (ECMA-368) MAC protocols are combined and proposed to such mixed traffic environment, by varying the portions of superframe according to traffic type. It is shown that the proposed WiMedia UWB MAC protocol can provide reliable mixed video and shipboard control data traffic as well.

• 스마트미디어저널
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• 제1권1호
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• pp.48-52
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• 2012

해양플랜트에 대한 설계 엔지니어링 기술을 확보하는데 있어 신뢰성 있는 평가 수행이 중요한 위치를 차지하고 있다. 국내 해양플랜트 공정설계 및 기본설계기술의 자립화를 위해서는 신뢰성 평가 기반의 설계검증 기술개발이 필요하고, 이를 위해 신뢰성 있는 실증실험 데이터 확보가 중요한 요소이다. 따라서, 신뢰성 있는 데이터를 확보하기 위해서는 해양플랜트 환경모사 실증시험 시스템이 구축되어야 한다. 본 연구에서는 해양플랜트 공정모듈 환경모사 시스템 구성을 위한 환경제어 및 측정변수 분석과 도출된 변수를 기반으로 데이터 수집장치 및 제어시스템의 설계 계획안을 연구한다.

• 한국통신학회논문지
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• 제39B권3호
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• pp.180-187
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• 2014

본 논문은 도로에 설치된 인프라 시스템 및 타 자율 주행 차량과 협력하여 주행하는 협력형 무인 자율 주행 차량 기술을 위한 멀티케스트 통신 기법을 소개한다. 협력형 자율 주행 차량은 주행 안전성 향상을 위해 인프라 시스템 및 주변 차량과 통신한다. 교환되는 정보는 차량 안전과 관련 된 정보이며 다수의 자율 주행 차량에게 정의된 시간 내에 반드시 전송되어야 한다. 그러나 차량 통신 국제 표준인 WAVE는 협력형 자율 주행을 위해 요구되는 멀티케스팅 통신의 높은 전송 성공을 보장하지 않는다. 본 논문에서는 WiVCL이라는 MAC 계층의 고신뢰 멀티케스트 기법을 제안한다. IEEE 802.11p 및 BMW와 비교한 결과 WiVCL은 높은 전송 성공률과 예측 가능한 전송 지연 시간을 보여줌을 확인할 수 있었다.

• 정보처리학회논문지D
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• 제10D권5호
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• pp.773-780
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• 2003

SecuROS(Secure & Reliable Operating System) 시스템은 FreeBSD 4.3 운영체제 커널에 접근 제어, 사용자 인증, 감사 추적, 암호화 파일 시스템, 신뢰 채널 등의 보안 기능을 추가 구현하여 시스템에 발생 가능한 해킹을 방지하고 차단하는 시스템을 말한다. 본 논문에서는 SecuROS의 핵심 기술 중에 하나인 접근제어 기법을 기술하고, 해당 접근제어 정책인 DAC, MAC, RBAC의 구현 내용을 소개하며, 접근제어 정책의 적용에 따른 보안성과 성능 시험을 위한 도구 및 방법을 나타낸다. 기존의 운영체제 환경과 새로운 접근제어 정책을 적용한 환경 사이의 보안성 및 성능의 상관 관계를 기술한다.

• Earthquakes and Structures
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• 제20권3호
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• pp.353-364
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• 2021

Natural hazards like earthquakes, high winds, and tsunami are a threat all the time for multi-story structures. The environmental forces cannot be clogged but the structures can be prevented from these natural hazards by using protective systems. The structural control can be achieved by using protective systems like the passive, active, semi-active, and hybrid protective systems; but the semi-active protective system has gained importance because of its adaptability to the active systems and reliability of the passive systems. Therefore, a semi-active protective system for the earthquake forces has been adopted in this work. Magneto-Rheological (MR) damper is used in the structure as a semi-active protective system; which is connected to the current driver and proposed controller. The Proportional Integral Derivative (PID) controller and reliable PID controller are two proposed controllers, which will actuate the MR damper and the desired force is generated to mitigate the vibration of the structural response subjected to the earthquake. PID controller and reliable PID controller are designed and tuned using Ziegler-Nichols tuning technique along with the MR damper simulated in Simulink toolbox and MATLAB to obtain the reduced vibration in a three-story benchmark structure. The earthquake is considered to be uncertain; where the proposed control algorithm works well during the presence of earthquake; this paper considers robustness to provide satisfactory resilience against this uncertainty. In this work, two different earthquakes are considered like El-Centro and Northridge earthquakes for simulation with different controllers. In this paper performances of the structure with and without two controllers are compared and results are discussed.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 춘계학술발표대회
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• pp.1288-1290
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• 2007

Congestion in WSN increases energy dissipation rates of sensor nodes as well as loss of packets and thereby hinders fair and reliable event detections. We find that one of the key reasons of congestion in WSN is allowing sensing nodes to transfer as many packets as possible. This is due to the use of CSMA/CA that gives opportunistic media access control. In this paper, we propose an energy efficient congestion avoidance protocol that includes source count based hierarchical and load adaptive medium access control. Our proposed mechanism ensures load adaptive media access to the nodes and thus achieves fairness in event detection. The results of simulation show our scheme exhibits more than 90% delivery ratio with retry limit 1, even under bursty traffic condition which is good enough for reliable event perception.

• 유공압시스템학회논문집
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• 제2권3호
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• pp.6-11
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• 2005

A household gas valve is used for flow control of LPG(Liquefied Petroleum Gas) or LNG(Liquefied Natural Gas) of which pressure is about $200mmH_2O(\fallingdotseq\;0.0196[bar])$. Currently, two kinds of valves such as rotary type and button type are widely used in many applications. But, these valves have some problems that they are not controllable and reliable. Piezo actuation combined with modem microelectronics provides a reliable, quiet, low energy, infinitely adjustable gas valve. In this paper, gas valve using piezo actuator which are bimorph and a circle type was studied. Also, Prototype for gas valve was manufactured and characteristics of the prototype gas valve were analyzed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1141-1144
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• 1999

This note addresses the problem of reliable (equation omitted) output-feedback control design for linear systems with actuator and/or sensor failures. An output feedback control design is proposed which stabilizes the plant and guarantees an (equation omitted)-norm bound on at-tenuation of augmented disturbances including all admissible actuator/sensor failures. Based on the linear matrix inequality (LMI) approach, the output- feedback controller design method is constructed by formulating to LMIs that cover all failure cases. Ef-fectiveness of this controller is validated via a numerical example.