• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.27-37
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• 2009

Sensor nodes forming a sensor network have limited energy capacity such as small batteries and when these nodes are placed in a specific field, it is important to research minimizing sensor nodes' energy consumption because of difficulty in supplying additional energy for the sensor nodes. Clustering has been in the limelight as one of efficient techniques to reduce sensor nodes' energy consumption in sensor networks. However, energy saving results can vary greatly depending on election of cluster heads, the number and size of clusters and the distance among the sensor nodes. /This research has an aim to find the optimal set of clusters which can reduce sensor nodes' energy consumption. We use a Genetic Algorithm(GA), a stochastic search technique used in computing, to find optimal solutions. GA performs searching through evolution processes to find optimal clusters in terms of energy efficiency. Our results show that GA is more efficient than LEACH which is a clustering algorithm without evolution processes. The two-dimensional GA (2D-GA) proposed in this research can perform more efficient gene evolution than one-dimensional GA(1D-GA)by giving unique location information to each node existing in chromosomes. As a result, the 2D-GA can find rapidly and effectively optimal clusters to maximize lifetime of the sensor networks.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.13-18
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• 2018

This paper is based on a simple approach that the most efficient learning of a multi-layered network is the process of finding the optimal set of weight vectors. To overcome the disadvantages of general learning problems, the proposed model uses a combination of features of EBP and OVSSA. In other words, the proposed method can construct a single model by taking advantage of each algorithm so that it can escape to the probability theory of OVSSA in order to reinforce the property that EBP falls into local minimum value. In the proposed algorithm, methods for reducing errors in EBP are used as energy functions and the energy is minimized to OVSSA. A simple experimental result confirms that two algorithms with different properties can be combined.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1147-1158
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• 2006

Clustering algorithm is an essential element to implement a hierarchical routing protocol, especially for a large-scale wireless sensor network. In this paper, we propose a new type of energy-efficient clustering algorithm, which maximizes the physical distance between cluster head and gateway by a neighbor node discovery mechanism. Furthermore, a slave/master patching scheme is introduced as a useful means of further improving the energy-efficiency. It has been shown that the number of cluster heads can be reduced by as many as 21% as compared with the existing clustering algorithms.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.697-700
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• 1998

스테레오 영상으로부터 3차원 거리 정보를 추출하는 일은 수학적으로 불량 설정 문제(ill-posed problem)이다. 본 논문은 스테레오 정합을 정칙화(regularization)와 최소화(minimization) 문제로 설정하여 변이 (disparity)를 구한다. 최소화할 에너지 함수로 기울기 벡터(gradient vector)를 사용하여 촤우 카메라의 차이에 대응하고, 영상에 존재하는 깊이 불연속점(depth discontinuties)을 찾아내어 이를 보존하면서 정칙화를 실행하는 스테레오 정합 알고리즘을 제시한다. 다양한 스테레오 영상에 대한 실험 결과를 함께 나타내었다.

• Journal of IKEEE
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• v.26 no.1
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• pp.56-61
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• 2022

Various efforts have been made worldwide to respond to environmental problems such as climate change. Research on artificial intelligence (AI)-based energy management has been widely conducted as the most effective way to alleviate the climate change problem. In particular, buildings that account for more than 20% of the total energy delivered worldwide have been focused as a target for energy management using the building energy management system (BEMS). In this paper, we propose a multi-armed bandit (MAB)-based energy management algorithm that can efficiently decide the energy consumption level of the lighting system in each room of the building, while minimizing the discomfort levels of occupants of each room.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.615-616
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• 2015

신재생에너지인 태양광발전으로 발생하는 전력과 부하에서 소비되는 소비전력으로 ESS(Energy Storage System)의 한 종류인 BESS(Battery Energy Storage System)의 운영 알고리즘을 제안 및 실증하고, 그 알고리즘은 부하를 평준화 시켜 계통에 걸리는 부담을 줄이고, 비용을 최소화 하며, 경제적으로 뛰어난 전력운영을 목표로 한다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.208-209
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• 2019

본 논문에서는 ESS를 이용한 전력 계통의 Peak-Shaving 제어 알고리즘 수립에 대한 연구 결과를 제시한다. 과거의 요일별 전력수요 데이터를 이용하는 경우 ESS가 포함된 전력 시스템의 연결점(PCC)에서 전력 및 에너지 평형 방정식을 수립할 수 있고, ESS의 전력 및 에너지 용량에 따른 전기요금 최소화를 목적 함수로 한 선형 계획법 문제를 정식화할 수 있다. 선형 계획법 문제 해결을 통해 ESS가 추가되는 경우에 대한 경제성을 분석할 수 있고, 이로부터 ESS의 적합한 용량도 선정할 수 있다. 또한 부하 크기 및 시간대별 ESS 최적 전력 이용 패턴을 확인할 수 있기 때문에 실 운용 로직 설계를 위한 가이드로 결과를 활용할 수 있다. 본 논문에서는 제안된 방법을 설명하기 위한 일 예시로서, 시간대별 전력 부하 패턴의 기존 연구 결과로부터 도출한 부하 전력 곡선을 이용하여 선형 계획법을 이용한 Peak-Shaving 최적 제어 결과를 제시하고, 이를 기반으로 실시간 운전 가능한 규칙 기반 알고리즘을 설계하여 ESS의 적용에 따른 요금 절감 효과를 제시한다.

• Journal of Korea Multimedia Society
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• v.10 no.1
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• pp.139-146
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• 2007

Many researches had been gone about method to track moving object using wireless sensor network. We examined tradeoffs that exist between quantity of energy and correctness of tracking, and we confirmed that can get more energy sayings through improved motion prediction method. The consumed energy in the tracking is used by sensor node for sensing the object, and tracking correctness is a differ once of actual object position from calculated value by sensing. Some tracking methods and controlling parameters causes a variation of tracking correctness and energy consuming, we can get best energy effectiveness by motion prediction algorithm. Furthermore, we get better tracking quality and energy effectiveness through using a motion prediction algorithm that consider acceleration. By the simulation, we know that if we use an accurate motion prediction algorithm, node activation range that is used for target's predicted position should be restricted to sensing range of sensor is better.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.328-330
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• 2005

이동 애드혹 네트워크 환경에서는 다수의 노드들이 계속적인 전원의 공급 없이 배터리로 작동을 하게 된다. 이러한 상황에서 이동 애드혹 네트워크에 참여하고 있는 각각의 노드들의 에너지 소모를 최소화 하기 위한 방법으로써 네트워크에 참여하고 있는 노드들 중에서 코디네이터를 선정하여 에너지를 절약하는 방법이 고안되어 왔다. 본 논문에서는 노드 개개의 수명은 물론 전체 네트워크의 수명을 보다 증가 시키기 위하여 코디네이터를 선정하는 알고리즘을 보다 효율적으로 개선하는 방법을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1233-1235
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• 2016

It is desirable to place virtual machines for minimizing the number of operational servers in order to save energy in high-density cloud computing environment. However, the compacted servers can incur heat islands. This paper firstly finds out the relationship between the server utilization by the virtual machine placement and the energy consumption of servers and heat from servers. Then, this paper proposes a virtual machine placement algorithm to save energy consumed and avoid heat islands.