• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.192-193
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• 2014

업무수행자(사용자)의 역할(Role)과 데이터 사용행위에 기반한 접근 및 권한 통제가 이루어져야 한다. 중요 정보의 대량 조회 및 변경 작업은 사전 결재를 득해야 한다. 일정 시간 무행위 세션에 대해 통제를 해야 한다.

• 정보관리연구
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• 제42권1호
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• pp.113-135
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• 2011

2010년 6월에는 IFLA에서 FRBR 시리즈의 세 번째 보고서인 '주제전거레코드의 기능상의 요건'(FRSAD)이 발표되었다. 이 개념모형은 최근의 주제전거 동향을 나타낼 뿐 아니라, FRBR 체제에 적합한 주제전거레코드를 위한 밑거름이 될 것이다. 이에 본 연구에서는 FRBR 시리즈의 맥락 안에서 FRSAD 모형을 분석하고, 이 모형을 우리나라의 주제명표와 서지레코드에 시범적으로 적용하였다. 이를 위해 개체와 속성, 관계를 중심으로 FRSAD 모형을 분석하였는데, 그 결과 FRSAD는 개체의 범주를 미리 규정하지 않은 개방성을 가지고 있으며, 테마와 노멘을 구분함으로써 주제명의 형식 측면 뿐아니라 개념 측면까지 강조하고 있음을 알 수 있었다. 그리고 이 개념모형을 FAST의 패싯과 연계하여 NLSH에 속한 일부 주제명의 개념구조와 주제전거와 관련된 서지레코드의 필드로 표현한 사례를 함께 제시하였다. 단, 본 연구에서는 인명과 단체명, 표제를 제외한 추가적인 개체로서의 주제전거 데이터만을 분석대상으로 하였다. 그 결과 FRSAD에서 별도로 정의하지 않은 제3집단 개체의 유형을 선정하는 기준과 그 기준을 주제명표에 일관되게 적용하는 방안이 필요함을 알 수 있었다. 앞으로는 보다 더욱 구체적인 적용 사례와 그 결과를 분석한 후속연구가 필요할 것이다.

• 생물환경조절학회지
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• 제9권4호
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• pp.201-206
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• 2000

여름철 고온기에 시설 이용율을 높이고 안정적인 생산을 하기 위해서는 고온 극복 시스템의 도입이 필요하며, 이러한 시스템을 도입하기 위하여는 적정 설비용량의 중요하다. 온실의 고온극복방법을 차광환기시스템, 차광환기 패드시스템, 차광환기 포그시스템으로 설정하고, 각 방법별로 시스템의 설계제원 결정을 위한 열평형식을 구성하였으며 현장 실험을 통하여 적용성을 검토하였다. 환기창 단면 풍속을 1분 간격으로 측정하여 유량으로 환산한 값을 환기량의 실측치로 하고 열평형식을 이용하여 계산한 환기량과 비교한 결과 비교적 잘 일치하는 것으로 나타났다. 열평형 모델의 입력변소중 피복재의 열관류이 1% 증가하면 필요환기량은 0.3% 감소하였고, 태양복사에 대한 증발산비(E)의 값이 1% 증가하면 필요환기량은 1.3%나 감소하는 것으로 나타났다. 따라서, E 값의 선택이 매우 중요하며 온실의 환기 및 냉방 설계기준을 설정하기 위해서는 여러 가지 작물의 상태에 따른 E값의 변화를 실측한 자료의 축적을 통해 가이드라인이 제시되어야 할 것으로 판단된다. 온실의 환기 및 냉방 설비 용량 결정을 위한 열평형 모델의 적용성을 검토하기 위하여 6가지의 동일한 조건에 대하여 시뮬레이션한 결과, 필요 공기교환율은 5.1∼7.7%정도, 증발수량은 6.8∼9.3%정도 fan and pad 시스템이 포그시스템에 비하여 큰 것으로 나타났다.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.28-38
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• 2016

The flexible control system for hydraulic pile hammer using main control valve is present to the requirement of rapidly reversing with high frequency. To ensure the working reliability of hydraulic pile hammer, the reversing performance of the main control valve should commutate robustness to various interfere factors. Through simulation model built in Simulink/Stateflow and experiment, the effects of relative parameters to reverse performance of main control are analyzed and the main interfere factors for reversing performance are acquired. Treating reverse required time as design objects, some structure parameters as control factors, control pressure, input flow and gaps between spool and valve body as interfere factors, the robust design of the main control valve is done. The combination of factors with the strongest anti-jamming capability is acquired which ensured the reliability and anti-jamming capability of the main control valve. It also provides guidance on design and application of the main control valve used in large flow control with interferes.

• 제어로봇시스템학회논문지
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• 제10권12호
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• pp.1223-1232
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• 2004

We present a new technique to the design and real-time implementation of fuzzy control system basedon digital signal processors in order to improve the precision and robustness for system of industrial robot in this paper. The need to meet demanding control requirement in increasingly complex dynamical control systems under significant uncertainties, leads toward design of intelligent manipulation robots. The TMS320C80 is used in implementing real time fuzzy control to provide an enhanced motion control for robot manipulators. In this paper, a Self-Organizing Fuzzy Controller for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variables of the controller. In the synthesis of a Fuzzy Logic Controller, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult Self-Organizing Fuzzy Controller is proposed for a hierarchical control structure consisting of basic and high levels that modify control rules. The proposed Self-Organizing Fuzzy Controller scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Performance of the SOFC is illustrated by simulation and experimental results for a Dual-Arm robot with eight joints.

• 대한조선학회논문집
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• 제42권6호
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• pp.566-574
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• 2005

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MO-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. Two control algorithms, anti-windup control and saturated sliding mode control, are studied in this paper. Control performance and robustness problem are checked out by numerical simulations.

• Advances in aircraft and spacecraft science
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• 제10권1호
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• pp.1-18
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• 2023

This paper investigates the integrated control of an air-breathing hypersonic vehicle considering the safety of propulsion system under acceleration. First, the vehicle/engine coupling model that contains a control-oriented vehicle model and a quasi-one-dimensional dual-mode scramjet model is established. Next, the coupling process of the integrated control system is introduced in detail. Based on the coupling model, the integrated control framework is studied and an integrated control system including acceleration command generator, vehicle attitude control loop and engine multivariable control loop is discussed. Then, the effectiveness and superiority of the integrated control system are verified through the comparison of normal case and limiting case of an air-breathing hypersonic scramjet coupling model. Finally, the main results show that under normal acceleration case and limiting acceleration case, the integrated control system can track the altitude and speed of the vehicle extremely well and adjust the angle deflection of elevator to offset the thrust moment to maintain the attitude stability of the vehicle, while assigning the two-stage fuel equivalent ratio to meet the thrust performance and safety margin of the engine. Meanwhile, the high-acceleration requirement of the air-breathing hypersonic vehicle makes the propulsion system operating closer to the extreme dangerous conditions. The above contents demonstrate that considering the propulsion system safety will make integrated control system more real and meaningful.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1857-1861
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• 2003

This paper proposes a method for controlling energy distribution to 1 phase induction heating coil by using the Binary Rate Modulation (BRM) Technique. Such method provides proper frequency to the heating coil's requirement by control the frequency at the resonance point, that is, 64-kHZ frequency band. System design are classified to 2 parts. The first part determines main frequency , and the second part generates the frequency from the 8-bit BRM derived from IC no. PAL22V10 in order to control the frequency for Full-bridge connected inverter when supplying the energy required by the 1 phase induction heating coil. Therefore, efficiency of the energy supply can be increate.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권7호
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• pp.309-316
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• 2005

In this paper we analyzed a dangerous failure and a safety requirement based on HIA (Hazard Identification and Analysis) of an interface model between CTC (Centralized Traffic Control) system and El (Interlocking) system, and assigned SU (Safety Integrity Level) by way of an risk estimation of the interface, which employed PHA (Preliminary Hazard Analysis) for the interface of the track control system, being managed as separated system between the centralized traffic control system and the interlocking system, An estimation which satisfies a safety reference of the international standard has been achieved through a quantification of the system failure rate and the dangerous failure rate of the interface model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.784-799
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• 2013

This paper presents an adaptive rate control scheme for streaming-based content sharing service. This scheme delivers multimedia contents from a user device to another device or seamlessly redirects streaming service across heterogeneous user devices. In the proposed scheme, a streaming server adjusts video quality level according to the network and client status. Our scheme is different from other rate control schemes, because the video quality at the server is decided not only based on the available bandwidth, but also based on the device characteristics and bandwidth requirement at the access network. We also propose a bandwidth estimation method to achieve more equitable bandwidth allocations among streaming flows competing for the same narrow link with different Round Trip Times (RTTs). Through the simulation, we prove that our scheme improves the network stability and the quality of streaming service by appropriately adjusting the quality of the video stream. The simulation results also demonstrate the ability of the proposed scheme in ensuring RTT-fairness while remaining throughput efficient.