• 제목/요약/키워드: passive method

검색결과 1,683건 처리시간 0.032초

압전 세라믹 감지기/작동기와 점탄성 재료를 이용한 지능형 복합 적층판의 진동 제어 (Vibration Control of Smart Laminated Composite Plates Using Piezoceramic Sensor/Actuators and Viscoelastic Material)

  • 강영규;서경민;이시복
    • 한국소음진동공학회논문집
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    • 제11권4호
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    • pp.37-42
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    • 2001
  • Active vibration control of laminated composite plates has been carried out to design structure with maximum possible damping capacity, using piezoceramic sensor/actuators and passive constrained-layer damping treatment. The equations of motion are derived for symmetrical, multi-layer laminated plates. The damping ratio(ζ) and modal damping(2ζ$\omega$) of the first bending and torsional modes are calculated by means of iterative complex eigensolution method for both passive and active vibration control. This paper addresses a design strategy of laminated composite plate under structural vibrations.

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A comparison of RPLA and PCR for detection of enterotoxins in methicillin-resistant Staphylococcus aureus(MRSA) strains isolated in dogs

  • Park, Son-il;Han, Hong-ryul
    • 대한수의학회지
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    • 제39권4호
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    • pp.806-810
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    • 1999
  • A multiplex-polymerase chain reaction (PCR) assay was used to detect staphylococcal enterotoxin production by 12 strains of Staphylococcus aureus isolated from clinical specimens. To evaluate the efficacy and/or sensitivity of this method, the results were compared to those obtained with the reversed passive latex agglutination kit (SET-RPLA, Denka Seiken, Japan). Of 10 strains positive by PCR were positive by RPLA but two strains, representing high sensitivity of the former method. Enterotoxin B was the most prevalent by the two methods. The kappa index between the two methods was 0.826, indicating a higher agreement and fully reliable for use. These results would suggest that sensitive, inexpensive, and relatively rapid multiplex-PCR technique may be an effective means for the detection of staphylococcal enterotoxin genes as an alternative to traditional methods such as kits or immunological methods, which depend upon the amount of enterotoxin produced.

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MR 감쇠기를 이용한 구조물의 변형된 슬라이딩 모드 제어 (Modified Sliding Mode Control of Structures Using MR Dampers)

  • 민경원;정진욱
    • 한국소음진동공학회논문집
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    • 제12권3호
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    • pp.243-250
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    • 2002
  • Semi-active control devices have received significant attention in recent Years because they offer the adaptability of active-control devices without requiring the associated large power sources. Magnetorheological(MR) dampers are semiactive control devices that use MR fluids to produce controllable dampers. This paper applies sliding mode control method using target variation rate of Lyapunov function for the control of structures by use of MR dampers. The three-story building model under earthquake excitation is analyzed by installing a MR damper in the first-story. The performance of semi-active controllers designed by clipped-optimal algorithm and modified sliding mode control algorithm is compared to the performance of passive-type MR dampers. The results indicate that semi-active controllers achieve a greater reduction of responses than passive-type system and especially the controller by modified sliding mode control method shows a good applicability in the view of response control and control force.

전류 고조파와 불평형 전원 전압 보상을 위한 직렬형 능동전력필터에 관한 연구 (A Study on the Series Active Power Filter for Harmonic Reduction and Unbalanced Source Voltage Compensation)

  • 오재훈;한윤석;김영석;원충연;최세완
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.191-194
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    • 2001
  • In this paper, we propose a series active power filter control method to compensate current harmonics and unbalanced source voltage. The system is composed of series active power filter and shunt passive filer that are tuned 5th and 7th harmonics. In this conventional system, series active power filter complements drawbacks of the shunt passive filter, namely improves harmonic compensation characteristics, and compensates unbalanced source voltage. In the proposed algorithm, compensation voltage for harmonic reduction is calculated by performance function, and compensation voltage for unbalanced source voltage is calculated in based on a synchronous reference frame. So, ultimate compensation voltage is sum of those two compensation voltages. By computer simulation, we verify the excellency of proposed method.

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SAW device를 이용한 900MHz 대역 수동형 RFID system의 인식거리 향상 연구 (Improve distance of Passive RFID system for 900MHz Using SAW device)

  • 박주용;김재권;김경환;여준호;범진욱
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2006년도 하계종합학술대회
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    • pp.975-976
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    • 2006
  • The passive type RFID (Radio Frequency Identification) System using Surface Acoustic Wave (SAW) tag at 900 MHz in the range of more than 1 m was fabricated. To improve interrogation range of the system propose a method to increase isolation between transmitter and receiver. This method using a direct conversion architecture achieves a leakage rejection of 10 dB increased compared with conventional system. Measured interrogation range is more than 1 m.

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EIS를 이용한 염해에 노출된 철근콘크리트의 부식개시 측정에 관한 실험적 연구 (An Experimental Study on Measurement of Corrosion Initiation in Reinforced Concrete Exposed to Chloride Using EIS Method)

  • 박동진;박장현;이광수;이한승
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2017년도 추계 학술논문 발표대회
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    • pp.61-62
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    • 2017
  • In this study, the initiation of steel corrosion was monitored due to chloride attack using embedded sensor. In general, Steel bars embedded in concrete are protected from corrosion by being forming a passive film on the surface. However, the passive film is destroyed by chemical erosion such as concrete carbonation and chloride penetration, and the rebar is exposed to the deteriorating factor and corrosion proceeds. In order to realize the initiation of steel corrosion, OCP and change of Impedance parameter were observed by using Half-cell and EIS method depending on cover depth. As result, 10mm cover showed the impedence increased in 6weeks.

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비디오 측정 시스템을 위한 효율적인 자동 초점 조절 알고리즘 (An Efficient Auto-focusing Algorithm for Video Measuring System)

  • 한광수
    • 한국정보과학회논문지:소프트웨어및응용
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    • 제32권9호
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    • pp.878-887
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    • 2005
  • 수동형 초점 조절 방식은 카메라를 통해 입력된 영상들을 분석하여 초점을 조절한다. 본 논문에서는 카메라를 이용한 정밀 측정 장비에 효율적으로 적용할 수 있는 수동형 자동 초점 조절 알고리즘을 제안한다. 영상에서 초점값 계산 알고리즘으로 가우시안 필터와 변형된 라플라시안 연산자를 사용한 SMLoG(Sum Modified Laplacian of Gaussian) 방법을 적용하고 초점값들을 이용한 정초점 위치 검색방법으로 가우시안 곡선 정합을 이용한다. 다양한 조명과 대상에 대하여 실험한 결과를 기존의 방법들과 비교하여 제안된 방법의 정확성과 효율성을 검증하였다.

구조-제어시스템의 동시최적설계를 위한 유전자알고리즘 및 Goal Programming 기법 (Genetic Algorithm and Goal Programming Technique for Simultaneous Optimal Design of Structural Control System)

  • 옥승용;박관순;고현무
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2003년도 추계 학술발표회논문집
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    • pp.497-504
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    • 2003
  • An optimal design method for hybrid structural control system of building structures subject to earthquake excitation is presented in this paper. Designing a hybrid structural control system nay be defined as a process that optimizes the capacities and configuration of passive and active control systems as well as structural members. The optimal design proceeds by formulating the optimization problem via a multi-stage goal programming technique and, then, by finding reasonable solution to the optimization problem by means of a goal-updating genetic algorithm. The process of the integrated optimization design is illustrated by a numerical simulation of a nine-story building structure subject to earthquake excitation. The effectiveness of the proposed method is demonstrated by comparing the optimally designed results with those of a hybrid structural control system where structural members, passive and active control systems are uniformly distributed.

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Transfer of Cupric Sulfate across Rat Small Intestine, in Vitro and Effect of Chelating Agents on It's Transfer

  • Kim, Chong-Kil;Choi, Seung-Gi;Rho, Young-Soo
    • Archives of Pharmacal Research
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    • 제11권2호
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    • pp.81-86
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    • 1988
  • The transfer of cupric sulfate across the rat small intestine in vitro was studied by perfusion method using the segments of everted rat small intestine. Copper transport was approximately propotional to the metal concentration in the mucosal solution and no difference was observed in the metal transport among rat duodenum, jejunum and ileum. It was suggested from these results that copper transport across the rat small intestine would occur by passive diffusion. The effect of various chelating agents on copper transport across the rat small intestine n vitro and its uptake by the intestine were also studied. Copper transport was greatly enhanced in the presence of EDTA and NTA. Copper uptake decreased to a greater extent in the presence of EPTA and NTA.

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수동 소나 시스템을 위한 실효치교차율 분석 기반 음향센서 결함 탐지 기법 (An acoustic sensor fault detection method based on root-mean-square crossing-rate analysis for passive sonar systems)

  • 김용국;박정원;김영신;이상혁;김홍국
    • 한국음향학회지
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    • 제36권1호
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    • pp.30-38
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    • 2017
  • 본 논문에서는 수동 소나 시스템을 위한 수중 음향 센서 결함 탐지 기법을 제안하였다. 일반적으로 수동 소나 시스템에서는 수십개의 음향 센서를 통해 얻은 음향 신호를 이용하여 배열 신호처리 기법을 이용해 처리된 신호를 협대역 또는 광대역 분석을 위한 2차원 영상 형태로 전시한다. 운용 소프트웨어에서 전시되는 탐지 결과는 배열 신호처리를 통해 누적된 결과값을 전시하기 때문에, 단일 센서 채널의 결함 또는 고장에 따른 신호의 이상 여부를 판단하는데 어려움이 있다. 따라서 본 논문에서는 인접 채널간 실효치 비교 및 실효치교차율(Root Mean Square Crossing-Rate, RMSCR) 분석기반 센서 자동 결함 탐지 기법을 제안하고, 결함 센서 채널에 대한 처리 기법을 비교 분석하였다. 제안된 기법의 성능 분석을 위하여 일부 연안 지역에서 실제 운용 중인 센서 배열을 통해 획득된 신호를 이용하여 결함 탐지 정확도를 측정하고, 결함 처리 기법의 성능을 비교하였다. 실험을 통해 제안된 기법이 높은 RMS의 주변소음 환경에서도 높은 결함 탐지 정확도를 보였으며, 결함 처리 기법으로는 0으로 설정 처리 기법이 가장 높은 성능을 보였다.