• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.168-169
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• 2017

중앙 전력과 단절된 독립형 마이크로그리드는 발전된 신재생 에너지를 저장하는 ESS의 효율적인 운영을 통해 블랙아웃을 방지하고 디젤 발전기의 발전 비용을 최소화하는 것이 필요하다. 본 논문에서는 기상 정보를 이용하여 신재생 에너지 발전량을 예측하고, 최적화 알고리즘을 이용해 생성된 후보 계획의 평가 시 ESS의 SOC를 유지하지 못하는 경우 페널티를 부여함으로써 신재생 발전량 예측의 오류에 대비하였다. 시뮬레이션 실험을 통해 제안하는 SOC 유지를 고려한 운영 계획 최적화 방안이 기존의 예측 제어 기반 최적화 방안에 비해 블랙아웃을 방지하면서도 디젤 발전 비용을 절감할 수 있음을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.250-252
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• 2019

국내의 전력 산업은 부정확한 전력수요 예측으로 전력부족과 공급과잉의 주기적 반복이 발생하여 전력 과생산, 에너지 낭비, 전력 과소비와 요금 체납 등의 문제가 발생하고 있다. 이를 해결하기 위해 본 논문에서는 LSTM 알고리즘을 사용하여 전력사용량 예측하고, 정량의 전력을 선구입 할 수 있도록 설계하였다. 제안하는 시스템은 스마트그리드 환경과 인공지능으로 정량의 전기를 구입 할 수 없는 기존의 전력 산업 문제를 보완하여 소비자의 전기요금 절감과 에너지 절약이 가능하다.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.532-543
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• 2004

Mobile Ad hoc NETworks (MANET) consist of mobile nodes which are usually powered by battery Approaches for minimizing power consumption have been proposed for all network layers and devices. IEEE 802.11 DCF (Distributed Coordination Function), a well-known medium access control protocol for MANETS, also defines a power save mode operation. The nodes in power save mode periodically repeat the awake state and the doze state in synchronized fashion. When all nodes are in the awake state, the exchange the announcements for the subsequent message transmission with neighbors. The nodes that send or receive the announcements stay awake for data transmission, and others go into the dole state. The previous works for enhancing the power save mode operation have focused on shortening the duration of the awake state. We observed that the longer sleeping period results in seriously long delivery latency and the consequent unnecessary power consumption as well, because the packets can move forward only one hop for a fixed interval. In this paper, we propose an improved protocol for the power save mode of IEEE 802.11 DCF, which allows the flooding packets to be forwarded several hops in a transmission period. Our approach does not reduce the duration of compulsory awake period, but maximizes its utilization. Each node propagates the announcements for next flooding to nodes of several hops away, thus the packets can travel multiple hops during one interval. Simulation results of comparison between our scheme and the standard show a reduction in flooding delay maximum 80%, and the unicasting latency with accompanying flooding flows near 50%, with slight increase of energy consumption.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.221-227
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• 2013

In this paper, zero-energy house in order to monitor the energy savings come with Zigbee communication temperature humidity, smoke detection, illumination and CO2 to develop complex sensor board a protocol for handling about it dealt. In particular, indoor space to mount the sensor based on the location of the control algorithm, so it varies through the Zigbee wireless sensor mounting position is free, and the advantage of being able to change. Also, the energy loss that occurs through the window can be reduced to the room lighting can play an important role in the control system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.20-28
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• 2008

It is prevalent to research on the energy saving systems using daylight. Daylight responsive dimming systems are to automatically control lighting output by available daylight for maintaining target illuminance on the workplane. The system application is not popular because of blocked daylight by shading systems. Automated roller shading systems automatically control shade height by sun position and sky conditions. Both daylight responsive dimming systems and automated roller shading systems should be integrated for energy savings and visual luminous environment. In this research, software are developed and integrated for control of integrated systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.932-938
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• 2017

This paper presents the structure of an energy management system for distributed energy resources of a grid-connected microgrid. The energy management system of a grid-connected microgrid collects information of the microgrid such as the status of distributed energy resources and the time varying pricing plan through various protocols. The energy management system performs forecasting and optimization based on the collected information. It derives the operation schedule of distributed energy resources to reduce the microgrid electricity bill. In order to achieve optimal operation, the energy management system should include an optimal scheduling algorithm and a protocol that transfers the derived schedule to distributed energy resources. The energy management system operates as a rolling horizon controller in order to reduce the effect of a prediction error. Derived control schedules are transmitted to the distributed energy resources in real time through the international standard communication protocol.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.171-174
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• 2011

서버 클러스터에서 부하 분산기는 사용자의 요청을 각 서버로 분산시키는 역할을 한다. 리눅스 가상 서버(LVS: Linux Virtual Server)는 소프트웨어적으로 사용되는 부하 분산기로서 여러 가지 스케줄링 방식들을 가지고 있다. 그러나 부하 분산 시에 서버의 유동적인 부하 정보를 반영하지 못하는 단점이 있다. 이에 개선된 방식으로 서버의 동시 연결 개수에 따라 상한계(Upper Bound)와 하한계(Lower Bound)를 설정하고, 요청을 분산하는 동적 스케줄링(Dynamic Scheduling)이 존재한다. 그러나 서버의 상태에 따라 상한계와 하한계가 바뀔 수 있음에도 불구하고 이 값들이 고정되어 있다는 단점을 가진다. 본 논문에서는 기존 부하 분산 방법의 단점을 극복하는 서버 전력 정보에 기반한 스케줄링 방식을 제안한다. 제안된 방식은 서버의 부하 정보를 기반으로 에너지를 추정하고 전력 수치를 기반으로 LVS의 가중치 테이블을 주기적으로 갱신한다. 그리고 부하 분산기는 클라이언트로부터 요청 받은 트래픽을 각 서버의 에너지 소모 상태에 따라 적용시킴으로써 에너지 소모가 최소화되도록 부하를 분산한다. 또한 서버의 상태에 따라 상한계와 하한계가 바뀔수 있음을 고려하여 상한계와 하한계를 설정하지 않고 서버의 상태에 따라 적절하게 요청이 분배되도록 하였다. 15대의 PC를 사용하여 실험을 수행하였으며, 실험 결과는 기존 부하 분산 알고리즘 중 성능이 가장 좋은 알고리즘에 비해 서버의 성능이 동일한 경우 성능 및 소비전력 면에서 거의 동등하였고, 서버의 성능이 상이한 경우 50.2% 성능 향상 및 27.3% 소비 전력 절감을 확인하였다.

• Journal of Navigation and Port Research
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• v.36 no.1
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• pp.35-41
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• 2012

In this paper, we analyze the current submarine cooling system and study control algorithms for cooling system. Cooling system are installed in the submarine propulsion motor to protect the motor from high-temperature by iron loss and copper loss. The cooling system control the sea water and fresh water pump RPM to keep the motor temperature stable by external environment and motor RPM holding time. The cooling system simulation program is made for checking the cooling performance, and simulation is performed with various control strategy. The results with proposed cooling algorithm is shown to improve the thermal stability and efficiency of cooling system.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.195-201
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• 2010

In this paper, a cooling system of high-power propulsion motor with Energy Saving System(ESS) is described. Normally, the cooling system for ship consists of fresh water pump, sea water pump, 3-way valve and cooler. In the cooling system, F.W(Fresh Water) and S.W(Sea Water) pump is operated on rated rpm, and the 3-way valve is controlled for preventing over-cooling. So, the consumption power of pump's motor is changed according to a sea water temperature. In the proposed cooling system, F.W. pump and S.W pump is controlled by inverter, and it is can be reduced the consumption power. Also, it is proved with simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1A
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• pp.28-36
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• 2005

Wireless Sensor Networks are the technology, in which various applications such as surveillance and information gathering are possible in the uncontrollable area of human. And numerous studies are being processed for the application of ubiquitous network environment. One of major issues in sensor network is the research for prolonging the lifetime of nodes through the use of various algorithms, suggested in the mac and routing layer. In this paper, aiming at reducing energy waste, caused by redundant transmission and receipt message, we propose the mac protocol using active signal and analysis performance through simulation.