• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.516-522
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• 2014

This study was conducted to investigate the impact of the anthropogenic factors affecting distribution of the Red-crowned Crane and White-naped Crane wintering in Cheorwon, Korea. Especially, it was investigated that the impact power and its range of the anthropogenic effect to the feeding flock density in cranes due to the paved road, residential area, military facilities and greenhouse density. The Red-crowned Crane and the White-naped Crane showed the similar preference and sensitivity against anthropogenic factors, because correlation of feeding flock density of the Red-crowned Crane and White-naped Crane was similar in the same site. The feeding flock density of the cranes near the residential area was lower than that of area far from the area, and tended to increase within 2.5 km distance. The increasing tendencies of feeding flock density from military facilities and high traffic volume road were similar, but the density in military facilities increased within 0.8 km, and the density from high traffic volume road increased within 2 km. This results suggested that military facilities and the road with high traffic volume made significant influence on foraging densities to the certain range. As the distance from the road with low traffic volume increased, feeding flock density tended to decrease. The area near the low traffic volume road had high feeding flock density because remaining rice grains were preserved by intermittent disturbances in that area. If the density of greenhouse is lower than $40/km^2$, feeding flock density in the low greenhouses density area was higher than high greenhouses density area. However, there was no difference in the feeding flock density if the density of the green houses is higher than $40/km^2$.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.675-680
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• 2009

This article describes NO emission characteristics in SM coal combustion. Combustion experiments was performed in the method of increasing temperature after feeding coal and feeding coal after increasing temperature. NOx emission is in inverse proportion to combustion temperature at the fuel rich condition and it was caused by conversion fuel N to $N_{2}$ at the strong reduction condition. In addition, feeding gas flow rate increased as total fuel NOx increase by conversion of fuel N to NO at the oxidation condition. It could be separated in total fuel-N, volatile-N, char-N to NO according to analysis of total fuel NO emission from char combustion at each temperature. In the result, almost total NOx emission was caused by volatile-N in SM-coal.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.1
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• pp.54-60
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• 2003

Feeding traction loads from the public power system may lead to some current and voltage unbalance and consequently affects the operation of its energy-supply system and other equipment connected with it. This paper introduces an analysis of the current unbalance caused by the demands of an electric railway on a public power system. And the results with compensator and without compensator are simulated, and eventually the formula about the current unbalance is suggested. The Scott-connected transformer is adopted in Korea National Railway System. So Scott-connected transformer among the various transformer connection schemes is analyzed in this paper. Also, the formulas about the unbalance and compensating current can be derived by using two parameters(M-phase and T-phase current) of secondary Scott-connected transformer. So, the practical and accurate simulation can be done through dynamic models by using scheduling of traction.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.7-11
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• 2007

PCB Power-Bus (comprising power/ground planes) impedance and fields are evaluated by an efficient series expansion method that is suggested in this paper. It is used to investigate the structure's radiated emission(RE) levels and find acceptable ways of loading the power/ground planes such as decoupling capcitor(DeCap)s, balanced feeding and slits, in order to reduce the interferences. Also, the calculations and measurements of a proposed geometry are verified by vector fitting as a analysis model to check the behavior of the slit.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.55-64
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• 2016

The development of high-speed rail (HSR) has had a major impact on the power supply grid. Based on the monitored waveforms of HSR, a pattern recognition approach is proposed for the first time in this paper to identify the operating conditions. To reduce the data dimensions for monitored waveforms, the principal component analysis (PCA) algorithm was used to extract the characteristics and their waveforms from the monitored waveforms data. The dynamic time wrapping (DTW) algorithm was then used to identify the operating conditions of the HSR. Cases studies show that the proposed approach is effective and feasible, and that it is possible to identify the real-time operating conditions based on the monitored waveforms.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.524-527
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• 2004

When the electric tractions are stopped or driven through the falling slope way, it occured to surplus energy in the DC power line. At present, these energy are exhausted by breaking-system. The converter is not only capable of feeding energy back into the AC source during excessive regeneration. It is issued for this surplus energy regenerating system. These systems are faced with high voltage and high power for railway DC power regeneration. This paper proposed a parallel PWM converter how to solve these problem.

• Korean Business Review
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• v.2
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• pp.141-169
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• 1989

Most of the theories of collective bargaining outcomes start with a set of economic variables. The economic constraints, pressures, and incentives influence the bargaining power relationship between labor union and employer. In this paper, the critical macro and micro economic variables that need to be considered in analyzing the economic context of collective bargaining power relationship is outlined. The focus is on the role that economic forces play in shaping the results of bargaining, that is the outcome of negotiations. In this study, the elasticity of the demand for labor is introduced as one of the most important economic aspects that influence bargaining power. Unions will be most successful in increasing wages when they enjoy an inelastic demand for labor. If the demand for labor is not naturally inelastic, some institutional arrangement for "taking wages out of competition" must be sought. Inflation, business cycle, and income policy are influential in shaping both parties' goals and expectations as well. In addition to the analysis of the economic variables, the nature of power is diagonized with some introductory notions about its care and feeding before proceeding to the details of the above issues.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1100-1105
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• 2010

The high speed line and conventional line are a single-phase AC feeding system; and power supplies of different phases meet at SS(SubStation)s or SP(Sectioning Post)s. These sections should be negotiated with the main circuit breaker in the traction vehicle switched off, whereby the length of the neutral zone prevents the pantographs shunting adjacent overhead line section. In order for electric railway vehicles to make power running there, there must be a power supply changeover section (approx. for 1km), where a changeover switch changes a power supply to the other power supply of a train running direction sequentially. For a thorough changeover switching control, the precise train position detection is necessarily required. In this paper, to realize the ground-based train position detection method, configuration scheme of train position detection equipment is suggested by using track circuit and axle counter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.573-576
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• 2012

We have analyzed the induction effects by separation distance between the power feeding station and the telecommunication cables. To do this we measured the induced voltage in 11 sections(10km) between Jangseong and Imgok at Jeon-nam province using telecommunication cable installed nearby KTX's feeder line. Sub-section has about 1km length of telecommunication cable. And we used normalization method in installed length of telecommunication cables and mutual inductance to analysis the induction effects more rationally.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.384-391
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• 2006

The harmonic currents generated along with the operating speed of electrical railroad traction are very difficult to analyze because of its nonlinear characteristics. This paper therefore presents probabilistic approach for the evaluation of harmonic currents about the operating speed of the arbitrary single traction. To use probabilistic method for railroad system, PDF(Probability Density Function) using measuring data based on the realistic h 따 monic currents per operating speed is calculated. Measuring data of harmonic current per operating speed is obtained using the result data of PSCAD/EMTDC dynamic simulation based on an IAT(Intra Airport Transit) in Incheon International Airport. The means(expected values) and variances of harmonic currents of single traction also are obtained by the PDF of the operating traction speed and harmonic currents. The uncertainty of harmonic currents can be calculated through the mean and variance of PDF. The probability of harmonic currents generated with the operating of arbitrary many tractions is calculated by the convolution of functions. The harmonics of different number of tractions are systematically investigated to assess the TDD(Total Demand Distortion) for the railroad system. The calculation of TDD was carried out using Monte-Carlo Simulations(MSCs) and the results of TDD evaluation of the power quality in the IAT power feeding system.