• 한국철도학회논문집
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• 제12권6호
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• pp.878-886
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• 2009

본 논문에서는 열차 운전시 최적의 에너지 효율을 얻기 위해서 GA(Genetic Algorithm)를 이용하여 열차 속도 프로파일을 생성하는 최적 알고리즘을 제시하고 시뮬레이션을 통해 유효성을 보였다. 역간의 열차 운전 모드를 최대 역행, 타행, 최대 제동으로 간략화 시키고 타행지점을 조절하여 열차 운전시 소비되는 에너지를 최소화 시키는 방식을 기본으로 하여, 정해진 거리의 두 역간을 정해진 운전시간 내에 도달하기 위하여 목표 운전시간을 이용하여 적합도(Fitness) 함수를 설정한 후, GA 알고리즘을 적용하여 역간 거리와 목표 운전시간의 두 제한요소를 모두 만족시키는 타행 지점들을 결정하였다. 시뮬레이션 결과 두 제한 요소들을 만족하는 타행 지점이 여러 개가 존재함을 확인하였고, 각 타행지점들에 따른 소비 에너지를 도출하여 에너지 소비량이 가장 적은 타행지점을 선정하여 최종적인 열차속도 프로파일을 결정하였다. 시뮬레이션을 위해 Simulink를 이용하여 열차성능 시뮬레이션 블록들과 GA 블록들을 설계하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.888-894
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• 2011

This paper is a study of optimal train driving strategy to minimize the energy consumption. Optimal driving strategy can be analyzed as an optimal problem which have constraints by using Largrangian Function and Kuhn-Tucker condition. We simulate the section between Konkuk University Station and Seongsu Station which is on outer circle line of the Seoul Metro line No.2 by using MATLAB and consider the straight level track and the speed limit.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.1259-1262
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• 1998

This paper introduced a scheme for finding the relationships between the measurements and tracks in multi-target tracking (MTT). We considered the relationships between targets and measurements as MRF and assumed a priori as a Gibbs distribution. An energy function is defined over the measurement space, as accurately as possible so that it may incorporate most of the important natural constraints. To find the minimizer of the energy function, we derived a new equation of closed form.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권2호
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• pp.80-84
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• 2009

Dynamic voltage and frequency scaling (DVFS) is an effective method to achieve low power design. In our work, we present an analytical DVFS method which judiciously exploits correlation information in runtime distribution while satisfying deadline constraints. The proposed method overcomes the previous distribution-aware DVFS method [2] which has pessimistic assumption on which runtime distributions are independent. Experimental results show the correlation-aware DVFS offers 13.3% energy reduction compared to existing distribution-aware DVFS [2].

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.267-273
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• 1998

This paper introduces an adaptive algorithm determining the measurement-track association problem in multi-target tracking(MTT). We model the target and measurement relationships with mean field theory and then define a MAP estimate for the optimal association. Based on this model, we introduce an energy function defined over the measurement space, that incorporates the natural constraints for target tracking. To find the minimizer of the energy function, we derived a new adaptive algorithm by introducing the Lagrange multipliers and local dual theory. Through the experiments, we show that this algorithm is stable and works well in general environments. Also the advantages of the new algorithm over other algorithms are discussed.

• 에너지공학
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• 제4권1호
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• pp.13-22
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• 1995

공정산업에서 열교환망의 최적화를 통한 에너지 회수 및 절감 기술의 개발을 목적으로, 여러 개의 핀치를 갖거나 또는 안전 및 배열 등과 같은 제약조건들이 주어진 계를 대상으로, 계의 분리법(system separation method)을 적용하여 신뢰도가 높은 목표값(target)을 설정하는 연구의 일환이다. 본 연구에서는 그 목표값의 10% 이내에 도달할 수 있도록 실제적인 열교환망 합성을 수행하는 프로그램 개발에 중점을 두었으며, 조업 중인 기존 공정에 적용해 본 결과, 연간 총비용의 15% 정도를 절감할 수 있는 결과를 얻을 수가 있었다.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 하계종합학술대회논문집
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• pp.5-8
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• 2000

This paper introduced a scheme for finding an optimal association matrix that represents the relationships between the measurements and tracks in multi-target tracking of Radar system. We considered the relationships between targets and measurements as MRF and assumed a priori of the associations as a Gibbs distribution. Based on these assumptions, it was possible to reduce the MAP estimate of the association matrix to the energy minimization problem. After then, we defined an energy function over the measurement space, that may incorporate most of the important natural constraints.

• Bulletin of the Korean Chemical Society
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• 제18권3호
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• pp.280-286
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• 1997

Potential energy function sets for some ion-exchanged A-type zeolites, K-A and Rb11Na1-A, were determined by introducing the X-ray crystal structures as constraints. The potential functions reproduced well the X-ray crystal structures of the monovalent ion-exchanged zeolites. The activation energies for the en- or de-capsulation of small molecules (H2, O2, N2, and CH4) and inert gases from the α-cage of model zeolites (Na-A, K-A, Rb11Na1-A, and Cs3Na9-A) were obtained by the molecular mechanical calculations. The calculated activation energies agreed well with experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.225-227
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• 2004

A sensor networkis composed of a large number of sensor nodes, which are densely deployed either inside the phenomenon or very close to it. One of the most important constraints on sensor nodes is the low power consumption requirement. Sensor nodes carry limited, generally irreplaceable, power sources. Therefore, while traditional networks aim to achieve high quality of service (QoS) provisions, sensor network protocols must focus primarily on power conservation. This paper presents the characteristics of energy consuming, average delay in 802.11 MAC, S-MAC that is specifically designed for wireless sensor networks. We analyze the energy consuming state in the 802.11 MAC in the simulation topology nodes, and measure average delay in 802.11 and S-MAC. Energy efficiency is the primary goal in this protocol design. 802.11 MAC is more efficient than S-MAC in the average delay, throughput. However S-MAC is an energy efficient protocol, a tradeoff between energy efficiency and delay.

• 천문학회보
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• 제39권1호
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• pp.32.1-32.1
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• 2014

Astronomical observations strongly suggest that the expansion rate of our universe is currently under acceleration. The nature of the so-called dark energy causing the acceleration is unknown, and it is one of the fundamental mysteries in the present day theoretical cosmology. Here we briefly review the current state of cosmic dark energy research in both theoretical and observational sides. Constraints on dynamical dark energy models (e.g., w-fluid, quintessence, and modified gravity) with recent observational data from type Ia supernovae, cosmic microwave background radiation, and large-scale structures in the universe indicate a preferred direction toward the simplest ${\Lambda}$CDM world model. We also discuss some issues regarding the early dark energy model and the spherical collapse of matter in the presence of dark energy.