• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.15-26
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• 2014

This paper proposes a Modified Particle Swarm Optimization with Time Varying Acceleration Coefficients (MPSO-TVAC) for solving economic load dispatch (ELD) problem. Due to prohibited operating zones (POZ) and ramp rate limits of the practical generators, the ELD problems become nonlinear and nonconvex optimization problem. Furthermore, the ELD problem may be more complicated if transmission losses are considered. Particle swarm optimization (PSO) is one of the famous heuristic methods for solving nonconvex problems. However, this method may suffer to trap at local minima especially for multimodal problem. To improve the solution quality and robustness of PSO algorithm, a new best neighbour particle called 'rbest' is proposed. The rbest provides extra information for each particle that is randomly selected from other best particles in order to diversify the movement of particle and avoid premature convergence. The effectiveness of MPSO-TVAC algorithm is tested on different power systems with POZ, ramp-rate limits and transmission loss constraints. To validate the performances of the proposed algorithm, comparative studies have been carried out in terms of convergence characteristic, solution quality, computation time and robustness. Simulation results found that the proposed MPSO-TVAC algorithm has good solution quality and more robust than other methods reported in previous work.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.52-59
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• 2008

This paper describes the secant method for solving the economic dispatch (ED) problem with generator constraints and transmission losses. The ED problem is an important optimization problem in the economic operation of a power system. The proposed algorithm involves selection of minimum and maximum incremental costs (lambda values) and then the evaluation of optimal lambda at required power demand is done by secant method. The proposed algorithm has been tested on a power system having 6, 15, and 40 generating units. Studies have been made on the proposed method to solve the ED problem by taking 120 and 200 units with generator constraints. Simulation results of the proposed approach were compared in terms of solution quality, convergence characteristics, and computation efficiency with conventional methods such as lambda iterative method, heuristic methods such as genetic algorithm, and meta-heuristic methods like particle swarm optimization. It is observed from different case studies that the proposed method provides qualitative solutions with less computational time compared to various methods available in the literature.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.572-575
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• 2005

디지털 콘텐츠 산업 즉, 영상 및 게임, 가상현실 등에서는 실시간으로 불꽃, 폭발, 연기, 액체, 눈, 비, 등의 특수효과를 시각적으로 사실적이고 화려한 영상으로 제공하기 위해 입자시스템을 사용한다. 디지털 콘텐츠 및 가상현실 제작자들과 응용 프로그램 개발자들에게 손쉽게 다양한 매개변수를 변경할 수 있는 인터페이스를 갖춘 GUI 환경이 제공된다면 다양한 디지털 콘텐츠에 사용자가 원하는 특수효과를 실시간으로 제공할 수 있을 뿐만 아니라 개발자에게 프로그래밍 기반을 제공할 수 있다. 본 논문에서는 디지털 콘텐츠 제작자 와 가상현실 응용 프로그램 개발자가 저비용 고품질의 디지털 콘텐츠를 제작할 수 있도록 유체속성, 기상현상 등의 다양한 특수효과를 손쉽게 적용할 수 있는 특수효과 생성기를 설계한다.

• Nuclear Engineering and Technology
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• 제40권4호
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• pp.299-304
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• 2008

A detection system was set up to measure the neutron generation rate of a recently developed D-D neutron generator. The system is composed of a Si detector, He-3 detector, and electronics for pulse height analysis. The neutron generation rate was measured by counting protons using the Si detector, and the data was crosschecked by counting neutrons with the He-3 detector. The efficiencies of the Si and He-3 detectors were calibrated independently by using a standard alpha particle source $^{241}Am$ and a bare isotopic neutron source $^{252}Cf$, respectively. The effect of the cross-sectional difference between the D(d,p)T and $D(d,n)^3He$ reactions was evaluated for the case of a thick target. The neutron generation rate was theoretically corrected for the anisotropic emission of protons and neutrons in the D-D reactions. The attenuations of neutron on the path to the He-3 detector by the target assembly and vacuum flange of the neutron generator were considered by the Monte Carlo method using the MCNP 4C2 code. As a result, the neutron generation rate based on the Si detector measurement was determined with a relative uncertainty of ${\pm}5%$, and the two rates measured by both detectors corroborated within 20%.

• Journal of Advanced Marine Engineering and Technology
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• 제35권7호
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• pp.907-913
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• 2011

Swirling flows are related to the spiral motion in the tangential direction in addition to the axial and radial direction using several swirl generators. These type of flows are used in combustion chambers to improve flame stability, heat exchanger to enhance heat transfer coefficients, agricultural spraying machines and some vertical pipes to move slurries or transport of materials. However, only a few studies three dimensional velocity profiles in a vertical pipe have been reported. In this present paper, 3 dimension particle image velocimetry(PIV) technique was employed to measure the velocity profiles in water along a vertical circular pipe with Reynolds number from 6000 to 13,000. A tangential inlet condition was used as the swirl generator to produce the required flow. The velocities were measured with swirling flow in the water along the test section using the PIV technique.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.320-330
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• 2008

This paper presents an improved dynamic programming (IDP) approach to solve the economic power dispatch problem including transmission losses in power systems. A detailed mathematical derivation of recursive dynamic programming approach for the economic power dispatch problem with transmission losses is presented. The transmission losses are augmented with the objective function using price factor. The generalized expression for optimal scheduling of thermal generating units derived in this article can be implemented for the solution of the economic power dispatch problem of a large-scale system. Six-unit, fifteen-unit, and forty-unit sample systems with non-linear characteristics of the generator, such as ramp-rate limits and prohibited operating zones are considered to illustrate the effectiveness of the proposed method. The proposed method results have been compared with the results of genetic algorithm and particle swarm optimization methods reported in the literature. Test results show that the proposed IDP approach can obtain a higher quality solution with better performance.

• 한국산업융합학회 논문집
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• 제26권6_1호
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• pp.1001-1010
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• 2023

To solve the problem that photovoltaic panels can not harvest electrical energy at a cloudy day and night, a floating solar thermoelectric generator (FSTEG, hereafter) is studied. The FSTEG is consisted of a dome shaped Fresnel lens to condense solar energy, a thermoelectric module connected with a heat sink to keep temperature difference, a floating system simulating a wavy ocean and an electrical circuit for energy storage. The dome shaped Fresnel lens was designed to have 29 prisms and its optical performance was evaluated outdoors under natural sunlight. Four thermoelectric modules were electrically connected and its performance was evaluated. The generated energy w as stored in a Li-ion battery by using a DC-DC step-up converter. For the application of ocean environment, the FSTEG was covered by the dome shaped Fresnel lens and sealed to float in a water-filled reservoir. The harvested energy shows a potential and a method that the FSTEG is suitable for the energy generation in the ocean environment.

• 정보과학회 논문지
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• 제42권2호
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• pp.190-202
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• 2015

스마트폰내 GPS 및 다양한 센서 데이터를 이용하여 스마트폰 사용자의 이동 패턴을 학습하고, 이를 기반으로 사용자 목적지와 경로를 예측하여 사용자의 의도에 맞는 서비스를 제공하는 위치기반 지능형 개인화 서비스(Intelligent personal assistant) 연구가 활발히 진행 되고 있다. 위치기반 개인화 서비스의 지능성은 불완전한 센서 데이터로부터 사용자 이동 정보를 처리하여, 실시간으로 사용자의 경로를 예측하는 정확성과 효율성에 좌우된다. 본 논문은 불완전한 정보로부터 사용자의 경로와 목적지를 추론하는 동적 베이지안 네트워크 기반의 강인한 파티클 필터(Robust particle filter)를 제안한다. 제안한 강인한 파티클 필터 방법은 부정확하고, 불완전한 센서 정보를 보완할 수 있는 파티클 생성, 실시간에 계산 복잡도를 감소시키는 효율적인 스위칭 함수와 가중치 함수, 파티클의 정확도를 향상시키는 재표본화로 구성되며, 사용자의 목적지와 경로의 예측 정확성과 효율성의 성능을 향상시켰다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.579-584
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• 2001

Agglomerated and nonagglomerated SiO2 particles are synthesized in furnace by the electrohydrodynamic spraying method and the vapor feeding method for the test particle generator this study. These polydispersed particles are classified with DMA to extract equal mobility particles. Then these particles are introduced into CNC (Condensation Nuclei Counter) to see the pulse height using Multi-channel Analyzer. The response characteristics of these two kinds of particles in CNCs (TSI CNC 3022 and 3025A) have been studied as a function of particle size using mono disperse particles classified by DMA. The results show that the higher drag resistance particles, so called agglomerated particles have generated a lower CNC pulse height than the spherical particles for these two different CNCs, which means the nonagglomerated particles may start to grow larger than the agglomerated particles.

• 전기학회논문지
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• 제59권4호
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• pp.779-787
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• 2010

In this paper, We introduce electrical tracking generated from surface activity associated with flow of leakage current on insulator under wet and contaminated conditions and design electrical tracking pattern recognition system by using LabVIEW. We measure the leaking current of contaminated wire by using LabVIEW software and the NI-c-DAQ 9172 and NI-9239 hardware. As pattern recognition algorithm and optimization algorithm for electrical tracking system, neural networks, Radial Basis Function Neural Networks(RBFNNs) and particle swarm optimization are exploited. The designed electrical tracking recognition system consists of two parts such as the hardware part of electrical tracking generator, the NI-c-DAQ 9172 and NI-9239 hardware and the software part of LabVIEW block diagram, LabVIEW front panel and pattern recognition-related application software. The electrical tracking system decides whether electrical tracking generate or not on electrical wire.