• 제목/요약/키워드: Active Push

검색결과 79건 처리시간 0.02초

A High Frequency-Link Bidirectional DC-DC Converter for Super Capacitor-Based Automotive Auxiliary Electric Power Systems

  • Mishima, Tomokazu;Hiraki, Eiji;Nakaoka, Mutsuo
    • Journal of Power Electronics
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    • 제10권1호
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    • pp.27-33
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    • 2010
  • This paper presents a bidirectional DC-DC converter suitable for low-voltage super capacitor-based electric energy storage systems. The DC-DC converter presented here consists of a full-bridge circuit and a current-fed push-pull circuit with a high frequency (HF) transformer-link. In order to reduce the device-conduction losses due to the large current of the super capacitor as well as unnecessary ringing, synchronous rectification is employed in the super capacitor-charging mode. A wide range of voltage regulation between the battery and the super capacitor can be realized by employing a Phase-Shifting (PS) Pulse Width Modulation (PWM) scheme in the full-bridge circuit for the super capacitor charging mode as well as the overlapping PWM scheme of the gate signals to the active power devices in the push-pull circuit for the super capacitor discharging mode. Essential performance of the bidirectional DC-DC converter is demonstrated with simulation and experiment results, and the practical effectiveness of the DC-DC converter is discussed.

Overturning Resistance of Plain Concrete Piers in OSPG Railroad Bridges

  • Rhee, In-Kyu;Park, Joo-Nam;Choi, Eun-Soo
    • International Journal of Railway
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    • 제3권1호
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    • pp.1-6
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    • 2010
  • The steel plate-girder bridges with concrete gravity piers have possibilities of overturning by lateral inertial force which can be reproduced by sudden earthquake attack. This paper explores an overturning mechanism of existing concrete gravity pier onto the sandy soil in the event of lateral push-over load by in-situ experimental observation. The in-situ push-over experiment for pier with earth anchors between spread footing and rock beds exhibits a reasonable enhancement of ductility against overturning. In unanchored system, a flexural crack at cold joint of concrete pier is not developed because of the over-turning of the pier. This leads a global instability (rotation) of pier-footing system with relatively low stresses in pier itself. While a lateral load is persistently increased in anchored system, the successive flexural cracking failure at cold joint is observed even after the local shear failure of soil due to redistribution of stress equilibrium between soil and pier structure as long as a tensile action of anchor cable is active.

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시뮬레이션에 의한 모바일 와이맥스 네트워크에서 그룹단위 통신의 성능평가에 관한 연구 (A Study on Simulation and Performance Evaluation of Group Communication over Mobile Wimax)

  • 오문균;김재명;유대승;김대영;부만틴;노승환
    • 한국통신학회논문지
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    • 제35권6B호
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    • pp.921-929
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    • 2010
  • 그룹통신은 이동통신 환경에서 사용할 수 있는 중요한 응용분야의 하나이다. PoC(Push to Talk over Cellular)는 셀룰러 전화망에서 사용되는 그룹통신을 위한 서비스이며, 단방향(half duplex) 통신으로 통화 버튼을 한 번 누름으로써 한 사용자가 그룹에 속한 다수에게 통화를 할 수 있게 한다. 이러한 서비스를 바탕으로 본 논문에서는 모바일 와이맥스(802.16e) 네트워크에서 그룹통신 프로토콜을 설계하였다. 또한 설계된 프로토콜의 검증과 성능평가를 위해 시뮬레이션을 실행하였다. 성능평가 결과 개발된 그룹통신이 안정적으로 동작함을 확인할 수 있었으며, 성능이 허용 범위 내에서 정상적으로 동작함을 확인할 수 있었다.

규칙적인 운동이 간호대학생의 체력수준에 미치는 효과 (Effect of Regular Physical Exercise on Physical Fitness Level in Nursing Students)

  • 조영희
    • 기본간호학회지
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    • 제4권2호
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    • pp.267-282
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    • 1997
  • This study was to test the relationship between regular physical exercise and physical fitness in nursing students. These subjects were 54 volunteers who agreed with intention of this study and were composed of 24 active group and 30 non-active group. The selected physical fitness tests were grip strength and back strength for measuring muscular strength, sargent jump and standing broad jump for measuring power, push-up, sit-up, and heart rate for measuring total endurance, reaction time and side step test for measuring agility, stick test and stork stand for measuring balance, and trunk flexion and trunk extension for measuring flexibility. The conclusion acquired was as follows : 1) Grip strength had significant difference between active group of $29.5{\pm}5.9kg$ and non-active group $25.4{\pm}7.2kg$(t=2.283, p=.027), and back strength between active group of $54.1{\pm}13.7kg$ and non-active group of $44.7{\pm}15.7kg$(t=2.310, p=.025), 2) Sargent jump was lower with non-active group($44.9{\pm}8.6cm$) than with active group($45.3{\pm}8.8cm$), however, was not significant(t=.182, p=.856). Standing broad jump was significantly lower with non-active group of $161.3{\pm}28.7cm$ than with active group of $191.4{\pm}27.0cm$(t=3.939, p=.000). 3) Push-up showed significant difference between active group of $25.3{\pm}12.3times$ and non-active group of $11.5{\pm}5.1times$(t=5.572, p=.000), and sit-up between active group of $21.8{\pm}7.4times$ and non-active group of $17.1{\pm}5.8times$(t=2.631, p=.011), and heart rate between actvie group of $110.5{\pm}12.8$beats/min and non-active group of $121.5{\pm}9.5$beats/min(t=-3.648, p=.001). 4) Reaction time was significantly higher with non-active group of $.300{\pm}.051sec$ than with active group of $.341{\pm}.041sec$(t=-3.285, p=.002). Side step test was lower with non-active group($8.8{\pm}1.1times$) than with active group($9.2{\pm}1.2times$), however, was not significant (t=1.309, p=.196). 5) Stick test showed not significant difference between active group of $25.8{\pm}14.8sec$ and non-active group of $30.7{\pm}17.9sec$(t=-1.058, p=.295), and stork stand between active group of $4.5{\pm}3.2sec$ and non-active group of $3.7{\pm}3.5sec$(t=.918, p=.363). 6) Trunk flexion came out not significant difference between active group of $14.2{\pm}5.0cm$ and non-active group of $15.8{\pm}7.3cm$(t=-.927, p=.358), and trunk extension between active group of $67.1{\pm}6.5cm$ and non-active group of $67.3{\pm}6.6cm$(t=-.140, p=.889). 7) Power was shown to be significantly related to total endurance(r=.717, p=.000 ; r-.739, p=.000). 8) Total endurance was shown to be significantly related to agility(r=-.752, p=.000 ; r=.684, p=.000 ; r=-.664, p=.000 ; r=.598, p=.002 ; r=.864, p=.000 ; r=-.536, p=.007). These results suggest that regular physical exercise is effective in promoting and maintaining physical fitness. As the further study, it is necessary to reinvestigate the effect with more refined design.

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친환경 차량용 보조배터리 충.방전을 위한 양방향 3상 능동클램프 푸시풀 컨버터 (Bidirectional Three-Phase Active clamped Push-Pull Converter for Charge and Discharge of Auxiliary Battery in Eco-friendly Vehicles)

  • 한국인;김준근;최세완
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2010년도 하계학술대회 논문집
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    • pp.148-149
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    • 2010
  • 본 논문에서는 친환경 차량용 보조배터리 충 방전을 위한 3상 양방향 DC-DC컨버터를 제안한다. 제안한 컨버터는 클램프 스위치의 동작으로 전압 및 전류공진을 최소화하고 대전류단의 순환전류를 감소시켜 전류정격을 줄였다. 제안하는 컨버터의 이론적 해석과 시뮬레이션을 통해 타당성을 검증하였다.

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Pb계 Ceramics 기지상의 무전해 Ni 도금 (Electroless Ni Plating on Pb-base Ceramics)

  • 민봉기;유종수;최순돈;신현준
    • 한국표면공학회지
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    • 제32권4호
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    • pp.487-495
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    • 1999
  • In order to form metallic electrodes on PZT (Pb (Zr, Ti)O$_3$) ceramics, plating conditions for optimal electroless Ni deposition were investigated. Pb in PZT is the major component to inhibit the electroless deposition, because it plays a active role of catalytic poison in plating solution. Adhesion of the electroless Ni deposits is measured by push-pull scale test and peel test. Results such as deposition ability, deposition rate, and thickness of deposits showed in terms of concentration of etchant, composition of catalyzing solution, and composition and pH of electroless bath solution.

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리니어 모터를 위한 능동 자기 베어링의 설계 및 제어 (Design and Control of an Active Magnetic Bearing for Linear Motors)

  • 양광원;허경무
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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    • pp.119-122
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    • 2001
  • This paper deals with new type of active magnetic bearing (AMB) for the linear motors. We adopted optical sensing mechanism for the gap sensing. Using the laser and the PSD (Position Sensitive Device), the absolute rotor position is obtained independent of the profile of the guide rail. With this measurement, the rotor can be controller to follow the straight beam of the laser. Another advantage of optical sensing mechanism might be the elimination of the possible interference between the proximity sensor and the electro-magnet. By adopting the push-full actuating mechanism, the bearing stiffness is increased near the equilibrium position. For the simplicity, distributed control system is constructed. Eight independent PID control algorithm is used with the full order observer. Several simulation md test results are presented.

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재분배 기법 적용에 따른 모멘트 저항골조의 비선형 특성 평가 (Evaluation of inelastic performance of moment resisting steel frames designed by resizing algorithms)

  • 서지현;권봉근;박효선
    • 한국강구조학회 논문집
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    • 제18권3호
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    • pp.361-371
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    • 2006
  • 최근 전통적인 구조 최적화 알고리즘의 단점을 극복하기 위해서 부재 변위기여도를 이용뼈 부재 사이즈를 조절함으로써 건물의 변위을 만족시키는 재분배기법이 실용적인 고층 건물 변위설계법으로 인식되고 있다. 재분배 기법을 이용한 변위 설계법은 변위에 효과적인 부재는 물량은 증가시키고, 변위제어에 효과적이지 못한 부재의 물량은 감소시키는 방법으로 변위를 제어한다. 기존 연구에서 재분배 기법은 동적 변위기여도에 근거하여 지진하중을 받는 철골 구조물의 변위를 효과적으로 제어할 수 있었다 기존의 연구에서 재분배 기법은 정하중과 지진하중을 받는 고층 건물의 변위를 효과적으로 제어할 수 있었으나, 재분배 기법으로 설계된 구조물의 비선형 성능에 대한 평가는 이루어 지지 못했다. 본 연구에서는 변위 제어 뿐 만 아니라 비선형 특성을 함께 개선할 수 있는 재분배 기법을 개발하기 위한 기초 연구로서, 재분배 기법의 비선형 특성 평가 모델을 개발하고, 이를 구조 시스템 중에서 가장 단순한 형태인 철골 모멘트 저항 골조 예제에 적용히여 철골 모멘트 저항 골조에 대한 재분배 기법의 비선형 특성을 평가하였다.

폐쇄형 데크플레이트를 사용한 합성슬래브의 전단부착 특성에 관한 연구 (A Shear Bond Chracteristics of Composite Slab with Closed-Shape Deckplate)

  • 주기수;박성무
    • 한국강구조학회 논문집
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    • 제13권5호
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    • pp.557-566
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    • 2001
  • 데크플레이트를 사용한 합성슬래브가 합성거동을 발휘하기 위해서는 데크플레이트와 콘크리트의 부착강도가 확보되어야한다. 합성슬래브에서 전단부착강도는 콘크리트와 데크플레이트의 화학적 부착력, 마찰저항 기계적 상호작용에 의해 발생한다. 또 기계적 상호작용은 길이 방향 전단력 전달 장치인 엠보싱 및 쉬어코넥터, 데크플레이트 형상 등에 의해서 확보되어 진다. 그리고 기계적 상호작용의 효과는 상호 접착부의 수직박리를 구속할 수 있는 데크의 형상과 쉬어코넥터 설치에 따른 단부정착 여부에 따라 크게 달라진다. 그러므로, 본 연구에서는 폐쇄형 데크플레이트에 대하여 기계적 전달장치인 엠보싱과 쉬어 코넥터로 사용되는 스터드 볼트에 대한 전단 보강장치의 부착효과를 Push-off 실험을 통하여 규명하였으며 이들 인자들에 대하여 제안식을 제시하였다. 이는 합성슬래브 설계방법의 기초자료로 이용될 수 있을 것으로 사료된다.

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푸쉬업플러스와 데드리프트 운동 시 골반압박이 견관절과 요골반부 주위근의 근활성도와 체간 신전근 근력에 미치는 영향 (The Effect of External Pelvic Compression on Shoulder and Lumbopelvic Muscle sEMG and Strength of Trunk Extensor During Push Up Plus and Deadlift Exercise)

  • 황천종;김선엽
    • 한국전문물리치료학회지
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    • 제25권3호
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    • pp.1-11
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    • 2018
  • Background: Lumbopelvic stability is highly important for exercise therapy for patients with low back pain and shoulder dysfunction. It can be attained using a pelvic compression belt. Previous studies showed that external pelvic compression (EPC) enhances form closure by reducing sacroiliac joint laxity and selectively strengthens force closure and motor control by reducing the compensatory activity of the stabilizer. In addition, when the pelvic compression belt was placed directly on the anterior superior iliac spine, the laxity of the sacroiliac cephalic joint could be significantly reduced. Objects: This study aimed to compare the effects of EPC on lumbopelvic and shoulder muscle surface electromyography (EMG) activities during push-up plus (PUP) and deadlift (DL) exercise, trunk extensor strength during DL exercise. Methods: Thirty-eight subjects (21 men and 17 women) volunteered to participate in this study. The subjects were instructed to perform PUP and DL with and without the EPC. EMG data were collect from serratus anterior (SA), pectoralis major (PM), erector spinae (ES), and multifidus (MF). Trunk extensor strength were tested in DL exercise. The data were collected during 3 repetitions of all exercise and the mean of root mean square was used for analysis. Results: The EMG activities of the SA and PM were significantly increased in PUP with pelvic compression as compared with PUP without pelvic compression (p<.05). In DL exercise, a significant improvement in trunk extensor strength was observed during DL exercise with pelvic compression (p<.05). Conclusion: The results of this study indicate that lumbopelvic stabilization reinforced with external pelvic compression may be propitious to strengthen PUP in more-active SA and PM muscles. Applying EPC can improve the trunk extensor strength during DL exercise. Our study shows that EPC was beneficial to improve the PUP and DL exercise efficiency.