• 제목/요약/키워드: control loading system

검색결과 527건 처리시간 0.022초

노약자용 휠체어 리프트 유압시스템 설계 (Design of Hydraulic Power Lifter for the Elder and the Handicapped)

  • 이수철;임구
    • 한국산업정보학회:학술대회논문집
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    • 한국산업정보학회 2002년도 춘계학술대회 논문집
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    • pp.1-6
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    • 2002
  • 본 연구는 대중교통 수단인 버스를 이용하는 교통약자인 휠체어 장애인의 접근을 돕는 휠체어리프트 개발을 위하여 안전을 고려한 유압시스템과 제어장치를 제작하기 위한 설계기술에 대하여 논하고자 한다. 현대는 고령화시대에 진입하면서 노약자와 장애인의 이동권과 접근권이 문제로 대두되고 있다. 본 연구에서는 기존 전동휠체어장애인과 보호자를 버스에 탑승할수 있는 접근성을 향상하는데 중요한 역할을 하는 리프트를 제작하는 과정에서 발생되는 안정성과 편리성을 중심으로 리프트를 설계 제작하고자 한다. 이 설계기술은 노약자 및 장애인의 이동권과 접근권을 향상시킬 수 있는 전동휠체어리프트의 대량생산체제를 확보하기 위한 중요한 기초자료가 됨으로써 동 제품의 안전도와 정밀도 품질보증 확보에 큰 기여를 하게된다.

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의료기관의 서비스지향성 측정도구의 신뢰도와 타당도 평가 (Validity and Reliability of a Service Orientation Scale for Health Care Organization)

  • 이명하;박숙경;이옥주
    • 간호행정학회지
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    • 제20권4호
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    • pp.362-372
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    • 2014
  • Purpose: The purpose of this research was to develop and test the validity and reliability of the Service Orientation Scale for Health Care Organization. Methods: The Service Orientation Scale for Health Care Organization, $SERV^*OR$, was developed through forward-backward translation methods. Internal consistency and reliability, construct and criterion validity were calculated using SPSS Statistics WIN 17.0. Survey data were collected from 283 clinical nurses in a general hospital in J province. Results: The Service Orientation Scale for Health Care Organization showed reliable internal consistency with Cronbach's ${\alpha}$'s for the total scale ranging from .85~.91. Factor loading of the 30 items on four sub-scales ranged from .67~.83. The sub scales were named service leadership, service system, customer focus, and service control. Item convergent and discriminant validity were also established for the Service Orientation Scale for Health Care Organization. Criterion validity showed a significant correlation with customer orientation. Conclusion: The findings of the study demonstrate that the Service Orientation Scale for Health Care Organization has satisfactory construct and criterion validity, and reliability and can be used to measure service orientation.

전자도서관 웹사이트의 품질향상을 위한 사용성 평가에 관한 연구 (A Study on Usability Evaluation for Improving Quality of University Digital Library Website in Korea)

  • 이응봉;류범종;김우성;김석동
    • 한국문헌정보학회지
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    • 제36권1호
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    • pp.41-60
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    • 2002
  • 본 연구에서는 호서대학교 전자도서관 웹사이트를 대상으로 하여 웹사이트 사용성 평가도구를 이용한 분석(Doctor HTML 및 Web Site Garage)을 적용하여 웹브라우즈의 호환성 및 접속속도를 분석하였고, 온라인 설문조사를 실시하여 네비게이션, 기능성, 이용자의 통제, 언어 및 컨텐츠, 시스템 및 이용자 피드백, 일관성, 구조적 및 시각적 명료성 등의 주요 속성에 관한 분석 및 평가를 통하여 문제점 및 개선방안을 도출하였다. 그리고 분석 및 평가결과를 반영하여 사용성에 기반한 우리나라 대학의 전자도서관 웹사이트 구축에 적용할 수 있는 일반적 지침을 제시하였다.

U형 강봉을 사용한 PC 계단 접합부 개발 (Development of Improved PC Stair Connections Using U-Rods)

  • 장극관;서대원;천영수
    • 토지주택연구
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    • 제2권4호
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    • pp.509-516
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    • 2011
  • 프리캐스트 콘크리트는 현장작업을 최소화하고 공사품질을 보장할 수 있으며 공사기간을 단축시킬 수 있는 장점을 갖고 있다. 특히 계단실의 경우 재래식 거푸집을 사용할 경우 골조공사의 품질저하와 다수의 인력투입에 따른 생산성의 저하 및 시공의 어려움 등의 문제점이 있다. 본 연구에서는 PC 계단 접합부 상세를 개발하고, 제안한 접합부의 일체성확보와 사용성 및 안전성을 검증하기 위해 구조성능실험을 수행하였으며, 단순 핀접합 실험체에 비해 구속도의 증가, 내력, 강성 및 연성의 증가를 확인할 수 있었다.

A Zero Sequence Voltage Injection Method for Cascaded H-bridge D-STATCOM

  • Yarlagadda, Srinivasa Rao;Pathak, Mukesh Kumar
    • Journal of Power Electronics
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    • 제17권4호
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    • pp.1088-1096
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    • 2017
  • Load variations on a distribution line result in voltage fluctuations at the point of common coupling (PCC). In order to keep the magnitude of the PCC voltage constant at its rated value and obtain zero voltage regulation (ZVR), a D-STATCOM is installed for voltage correction. Moreover, the ZVR mode of a D-STATCOM can also be used to balance the source current during unbalanced loading. For medium voltage and high power applications, a D-STATCOM is realized by the cascaded H-bridge topology. In the ZVR mode, the D-STATCOM may draw unbalanced current and in this process is required to handle different phase powers leading to deviations in the cluster voltages. Zero sequence voltage needs to be injected for ZVR mode, which creates circulating power among the phases of the D-STATCOM. The computed zero sequence voltage and the individual DC capacitor balancing controller help the DC cluster voltage follow the reference voltage. The effectiveness of the control scheme is verified by modeling the system in MATLAB/SIMULINK. The obtained simulations are further validated by the experimental results using a dSPACE DS1106 and five-level D-STATCOM experimental set up.

Experimental study on effect of EBRIG shear strengthening method on the behavior of RC beams

  • Shomali, Amir;Mostofinejad, Davood;Esfahani, Mohammad Reza
    • Advances in concrete construction
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    • 제8권2호
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    • pp.145-154
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    • 2019
  • The present experimental study addresses the structural response of reinforced concrete (RC) beams strengthened in shear. Thirteen RC beams were divided into four different sets to investigate the effect of transverse and longitudinal steel reinforcement ratios, concrete compressive strength change and orientation for installing carbon fiber-reinforced polymer (CFRP) laminates. Then, we employed a shear strengthening solution through externally bonded reinforcement in grooves (EBRIG) and externally bonded reinforcement (EBR) techniques. In this regard, rectangular beams of $200{\times}300{\times}2000mm$ dimensions were subjected to the 4-point static loading condition and their load-displacement curves, load-carrying capacity and ductility changes were compared. The results revealed that using EBRIG method, the gain percentage augmented with the increase in the longitudinal reinforcement ratio. Also, in the RC beams with stirrups, the gain in shear strength decreased as transverse reinforcement ratio increased. The results also revealed that the shear resistance obtained by the experimental tests were in acceptable agreement with the design equations. Besides, the results of this research indicated that using the EBRIG system through vertical grooves in RC beams with and without stirrups caused the energy absorption to increase about 85% and 97%, respectively, relative to the control.

A study on the liquefaction risk in seismic design of foundations

  • Ardeshiri-Lajimi, Saeid;Yazdani, Mahmoud;Assadi-Langroudi, Arya
    • Geomechanics and Engineering
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    • 제11권6호
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    • pp.805-820
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    • 2016
  • A fully coupled non-linear effective stress response finite difference (FD) model is built to survey the counter-intuitive recent findings on the reliance of pore water pressure ratio on foundation contact pressure. Two alternative design scenarios for a benchmark problem are explored and contrasted in the light of construction emission rates using the EFFC-DFI methodology. A strain-hardening effective stress plasticity model is adopted to simulate the dynamic loading. A combination of input motions, contact pressure, initial vertical total pressure and distance to foundation centreline are employed, as model variables, to further investigate the control of permanent and variable actions on the residual pore pressure ratio. The model is verified against the Ghosh and Madabhushi high acceleration field test database. The outputs of this work are aimed to improve the current computer-aided seismic foundation design that relies on ground's packing state and consistency. The results confirm that on seismic excitation of shallow foundations, the likelihood of effective stress loss is greater in deeper depths and across free field. For the benchmark problem, adopting a shallow foundation system instead of piled foundation benefitted in a 75% less emission rate, a marked proportion of which is owed to reduced materials and haulage carbon cost.

Hygro-thermal effects on wave dispersion responses of magnetostrictive sandwich nanoplates

  • Ebrahimi, Farzad;Dabbagh, Ali;Tornabene, Francesco;Civalek, Omer
    • Advances in nano research
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    • 제7권3호
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    • pp.157-167
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    • 2019
  • In this paper, a classical plate model is utilized to formulate the wave propagation problem of magnetostrictive sandwich nanoplates (MSNPs) while subjected to hygrothermal loading with respect to the scale effects. Herein, magnetostriction effect is considered and controlled on the basis of a feedback control system. The nanoplate is supposed to be embedded on a visco-Pasternak substrate. The kinematic relations are derived based on the Kirchhoff plate theory; also, combining these obtained equations with Hamilton's principle, the local equations of motion are achieved. According to a nonlocal strain gradient theory (NSGT), the small scale influences are covered precisely by introducing two scale coefficients. Afterwards, the nonlocal governing equations can be derived coupling the local equations with those of the NSGT. Applying an analytical solution, the wave frequency and phase velocity of propagated waves can be gathered solving an eigenvalue problem. On the other hand, accuracy and efficiency of presented model is verified by setting a comparison between the obtained results with those of previous published researches. Effects of different variants are plotted in some figures and the highlights are discussed in detail.

Offshore wind turbine installation vessel dynamic positioning capability analysis with considering installation structures

  • Daeseong, Lim;S.W., Kim;Jeong-Hyun, Yoon;Seo-ho, Lee
    • Ocean Systems Engineering
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    • 제12권4호
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    • pp.461-477
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    • 2022
  • Dynamic Positioning (DP) is a system that uses computer-controlled thrusters, propellers, and other propulsion devices to automatically maintain a vessel's position and heading. In this study, a wind turbine installation vessel with DP capabilities was proposed for use in mild environmental conditions in the Yellow Sea. The thruster arrangements of the vessel were analyzed in relation to wind and current loads, and it was found that a four-corner arrangement of thrusters provided the best position-keeping performance. The vessel's DP control performance was also analyzed in relation to the increased environmental load caused by the presence of a wind turbine, using a capability plot. The vessel's performance was evaluated in three different states: floating with no load, during the loading of a wind turbine and suction buckets, and after the wind turbine has been installed. The use of 750 kW and 1,000 kW thrusters was also considered, and the environmental loads in the Saemangeum coastal area and the environmental load when a 5-Megawatt wind turbine is on board were assessed. The study concluded that at least four thrusters should be used for DP to safely manage the installation process of wind turbines.

2MN 유압식 힘 표준기의 설계 및 제작 (Design and fabrication of 2MN hydraulic force standard machine)

  • 강대임;송후근;이정태;안병덕;김창열;이재율;안병출;정광국;전영홍
    • 한국정밀공학회지
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    • 제11권5호
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    • pp.33-41
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    • 1994
  • For the establishment of large force standard and the accurate measurement of large force, 2MN hydraulic force standard machine which consists of loading frame, deadweight machine, two ram/cylinder systems and hydraulic control system was designed and fabricated. Measurement results of shapes for tow ram/cylinders reveal that the ratio of effective area is 200.094. The relative deviation of force stability for the machine is about .+-. 0.01% at 2MN and is less than .+-. 0.005% below 2MN. This machine may be widely used to calibrate the force measuring devices in industry and to test the force sensors.

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