• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.667-674
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• 2006

Dynamic analysis of the electrical transmission system including transmission towers and cables is carried out by a general purpose structural analysis computer program for examining the wind-resistance of the system The spectral representation method is introduced to generate dynamic wind loads by using the Kaimal's spectrum and the measured wind velocities from wind tunnel tests, respectively. The numerical simulation results show that the responses in the case of the measured wind velocities is slightly larger than those in the case of the code.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.234-239
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• 2009

This paper presents a theoretical and experimental investigation of the transmission and sensing characteristics of the biconically tapered cladded multimode fibers. The beam propagation method was used to examine the transmission characteristics with various structural parameters. The results show that the transmission of the biconically tapered cladded multimode fibers is sensitive to the mode of the input optical beam and the refractive index of the external medium. A refractive index sensor for the external medium was proposed based on the theoretical analysis, and its feasibility was demonstrated experimentally.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1543-1544
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• 2008

In this paper, we introduce a gaussian enveloped linear chirp signal that can change parameters for consideration of target material characteristics. Using the gaussian enveloped linear chirp signal, time-frequency domain reflectomety is able to detect fault location in power transmission line. we suggest design method of reference signal for power transmission line fault detection. This method is verified by locating fault in HIV low voltage power transmission line.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.31-39
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• 2013

Proper installation of Flexible AC Transmission Systems (FACTS) devices in existing transmission networks can enable power systems to accommodate more power transfer with less network expansion cost. The problem to maximize transmission system loadability by determining optimal locations and settings for installations of two types of FACTS devices, namely static var compensator (SVC) and thyristor controlled series compensator (TCSC), is formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP). For solving the MDCP, in the paper, the proposed method with fitness sharing technique involved in the updating process of the particle swarm optimization (PSO) algorithm, can diversify the particles over the search regions as much as possible, making it possible to achieve the optimal solution with a big probability. The modified IEEE-14 bus network and a practical power system are used to validate the proposed method.

• 한국군사과학기술학회지
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• 제11권3호
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• pp.19-29
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• 2008

Underwater acoustic(UWA) communication is one of the most difficult field in terms of severe channel environments such as multipath propagation, high temporal and spatial variability of channel conditions. Therefore, it is important to model and analyze the characteristics of underwater acoustic channel such as multipath propagation, transmission loss, reverberation, and ambient noise. In this paper, UWA communication channel is modeled with a ray tracing method and applied to image transmission. Quadrature phase shift keying(QPSK) and multichannel decision feedback equalizer(DFE) are utilized as phase-coherent modulation method and equalization technique, respectively. The objective is to improve the performance of the image transmission using vertical sensor array instead of single sensor in the viewpoint of bit error rate(BER), constellation diagram, and received image quality.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.682-687
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• 2000

In this paper, the simulation methods using transmission lines are studied and realized, which are necessary in design and analysis of hydraulic control systems. The basic idea of this method is that system components are separated by transmission line element for simulation. The PI-controller can keep inductance level as low as desired. It can also handle nonlinearities and discontinuities without flag signal when restarting integration. Parallel hydraulic circuits are simulated using parallel processing algorithm. To shoe that using variable timestep size in each subsystem, simulation time can be reduced. Performance of the simulation results is compared with that of Runge Kutta method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.228-230
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• 2006

This paper describes the information transmission method using communication networks between the devices in Photovoltaic Power System, and also represents the test result which carried out in the field. In this test, transmission signal waveform, polling time, response time and request/response frame were measured between the devices. The measured results show the excellent transmission characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.283-285
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• 2002

The paper describes a study of selection of existing a.c. Transmission facilities converted fur use with d.c. system. In order to increasing the power transfer capability of existing a.c. transmission facilities, d.c. is one of good alternatives. Some advantages and disadvantages of this method are discussed, and the selection method of existing transmission facilities for use with d.c. considering economics and stability is presented in this paper.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.27-32
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• 2007

Determination of crack depth in filed using the self-calibrating surface wave transmission measurement and the cutting frequency in the transmission function (TRF) is very difficult due to variations of the measurement conditions. In this study, it is proposed to use the measured full TRF as a feature for crack depth assessment. A principal component analysis (PCA) is employed to generate a basis of the measured TRFs for various crack cases. The measured TRFs are represented by their projections onto the most significant principal components. Then artificial neural networks (NNs) using the PCA-compressed TRFs is applied to assess the crack in concrete. Experimental study is carried out for five different crack cases to investigate the effectiveness of the proposed method. Results reveal that the proposed method can be effectively used for the crack depth assessment of concrete structures.

• KIEE International Transactions on Power Engineering
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• 제5A권2호
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• pp.193-198
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• 2005

This paper proposes a new method to handle transmission line losses using loss distribution factors (LDF) rather than marginal loss factors (MLF) in electricity market operation. Under a competitive electricity market, the bidding data are adjusted to reflect transmission line losses. To date the most proposed approach is using MLFs. The MLFs are reflected to bidding prices and market clearing price during the trading and settlement of the electricity market. In the proposed algorithm, the LDFs are reflected to bidding quantities and actual generations/ loads. Computer simulations on a 9-bus sample system will verify the effectiveness of the algorithm proposed. Moreover, the proposed approach using LDFs does not make any payments residual while the approach using MLFs induces payments residual.