• 한국전자통신학회논문지
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• 제17권6호
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• pp.1047-1054
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• 2022

네트워크 장비의 하드웨어 영역과 소프트웨어 영역을 분리하고 오픈소스 기반의 소프트웨어를 사용하여 네트워크를 정의하는 차세대 네트워크 기술인 SDN의 등장으로 기존 네트워크 체계가 가지고 있던 복잡성과 확장성의 문제를 해결하고 저비용으로 사용자의 환경과 요구조건에 맞춤형 네트워크 구성이 가능해졌다. 하지만, 컨트롤러와 스위치 간에 발생하는 많은 제어 통신으로 인한 네트워크의 부하가 발생할 수 있다는 구조적 단점을 가지고 있어 이를 효과적으로 해결하기 위한 네트워크 부하분산에 대한 많은 연구가 선행되었다. 특히 플로우 테이블과 관련된 부하분산 기법의 기존 연구에서는 플로우 엔트리에 대한 고려 없이 진행된 연구가 많아서 플로우 수가 많아지게 되면 패킷 처리속도가 떨어져 오히려 부하를 가중시키는 결과를 가져오기도 했는데, 본 논문에서는 이러한 문제점을 해결하기 위해 실시간으로 플로우를 모니터링하고 동적 플로우 관리 기법을 적용하여 플로우 수를 적정 수준으로 조절하면서도 높은 패킷 처리속도를 유지할 수 있는 새로운 네트워크 부하분산 기법을 제안한다.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권2호
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• pp.82-90
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• 2003

The work presented here is a design and an implementation of PID control system to regulate a supply duct outlet air temperature in PEM (Personal Environment Module). In PEM, the air is heated to the required temperature while it flows through the supply duct without any mixing chamber. This makes the control of air temperature in PEM difficult. A simulation is done first to understand the relationship between a temperature distribution in working area, flow rate and the outlet air temperature of PEM. Then a linear dynamic model of heating process in PEM is derived. P, PD and PID type control systems, to provide the rapid response without overshoot and saturation in heater command voltage, are designed using a linear model obtained. Experimentally obtained data shows that the control system satisfies the design criteria and works properly in controlling the supply duct outlet air temperature.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.71.2-71.2
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• 2005

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.324-329
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• 2005

This study considers that hydrologic stability evaluation of agricultural reservoirs designed by past standards and approximate increase methods of flood control when PMF(Probable maximum flood) flows in.

• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.64-68
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• 2016

These fields are integrated to visualize and finalize the proposed development, in simulation environment. SCADA (supervisory control and data acquisition) systems and distributed control systems (DCSs) are widely deployed in all over the world, which are designed to control the industrial infrastructures, in real ways. To supervise and control the various parts of designed systems; trends to require a deep knowledge to understand the overall functional needs of industries, which could be a big challenge. Industrial field devices (or network sensors) are usually distributed in many locations and are controlled from centralized site (or main control center); the communication provides various signs of security issues. To handle these issues, the research contribution will twofold: a method using cryptography is deployed in critical systems for security purposes and overall transmission is controlled from main controller site. At controller site, multimedia components are employed to control the overall transmission graphically, such as system communication, bytes flows, security embedded parameters and others, by the means of multimedia technology.

• 설비공학논문집
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• 제13권1호
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• pp.59-65
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• 2001

The work presented here is an implementation of PID control to achieve a required supply air temperature in PEM(Personal environment module). In PEM, the air is heated to the required temperature while it flows through the supply duct, without any mixing chamber. This makes the control of air temperature in PEM difficult. Linear dynamic model of heat transfer in PEM is first obtained. Then P, PD and PID type control systems, to provide the rapid response without overshoot and saturation, are designed and implemented experimentally. Data obtained shows that the control system satisfied the design criteria and works properly in controlling the supply air temperature.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (A)
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• pp.721-723
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• 2004

오늘날의 인터넷은 QoS를 보장하기 위해 다양한 방법을 사용하고 있는데, 본 논문에서는 Integrated-QoS 개념을 제안하고 이를 기반으로 Admission Control을 실행하는 Enhanced Differentiated Service(DiffServ)를 설계하였다. 본 논문은 IntServ(Integrated Service)와 DiffServ(Differentiated Service)의 장점을 결합하여, EF 클래스에 속하는 다수의 흐름들(flows)에 기존보다 QoS가 더욱 보장된 서비스를 제공할 수 있는 방안을 제시한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.94-97
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• 1999

In this paper, a new real-time neural network connection admission controller is proposed. The proposed controller measures traffic flows, cell loss rate and cell delay periodically each classes. The Neural network learns the relation between those measured information and service quality by real-time. Also the proposed controller uses the DWRR multiplexer with buffer dedicated to every traffic source in order to measure the delay that cells experience in buffer. Experimental result shows that the proposed method can control effectively heterogeneous traffic sources with diverse QoS requirement.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1213-1217
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• 2007

In this paper some sets of numerical simulations for passenger evacuation in a fire occurred underground station under various smoke-control ventilation modes. Passenger evacuation flows are calculated by EXODUS program. As input data for EXODUS program, distributions of temparature, smoke and toxicity due to fire in the underground station are evaluated by Fire Dyanamic Simulator (FDS).

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2012년도 전기공동학술대회 논문집
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• pp.276-278
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• 2012

This study was performed to investigate wake flow and unsteady flow characteristics using a model for actual shape of a wind breaker and visualization of flow through the particle image velocity. three control angle of flap were selected and instantaneous velocity distributions and flow characteristics were experimently investigated. It is found that as the control angle increase, the flows are characterized by the appearance of the growth of recirculation region.