• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.373-375
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• 2005

AC harmonic filters connected to the terminals of HVDC schemes fulfill two primary functions: to compensate for part or all of the reactive power absorbed by the converter, and to limit to an acceptable level the voltage distortion caused by the converter harmonics. this paper makes a direct comparison between tuned filters and damped filters, each designed for a long HVDC transmission scheme. It Is hoped that by comparing the two approaches a syudy to determine the suitability of filter types to AC systems can be promoted.

• Journal of Ocean Engineering and Technology
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• v.18 no.3
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• pp.40-43
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• 2004

A rational method is presented for estimating the power increase of a ship at sea. A probabilistic approach is applied to determine the weather condition at sea, A comparison is made between some full-scale data and the result of Swift's method. A comparison is also made to find differences among the results of eight kind methods for the wind added resistance of a VLCC in head wind. The mean difference between the results is 7％, in general, for a given relative wind speed.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.150-156
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• 2016

This paper compares the performances of permanent-magnet synchronous (PMS) and permanent-magnet vernier (PMV) machines for low-speed and high-torque applications. For comparison with the PMS machines, we consider two types of the PMV machine. The first one has surface-mounted permanent magnets (PMs) on the rotor and the other has PMs inserted on both sides of the stator and rotor. The PMS and PMV machines are designed to meet the condition of equal output power per unit volume. We analyze the magnetic fields of the machines using a two-dimensional finite element analysis (FEA). We then compare their performances in terms of the generated torque characteristics, power factor, loss, and efficiency.

• Journal of Power Electronics
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• v.11 no.5
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• pp.621-631
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• 2011

In space qualified DC-DC converters, optimization of the following electrical characteristics is of greater interest in comparison with other specifications; power loss/efficiency, output voltage ripple and volume/weight. The main goal of this paper is to present an appropriate solution for optimizing the above mentioned characteristics. For this purpose, a comprehensive power loss model of a DC-DC converter is fully developed. Proper models are also demonstrated for assessment of the output voltage ripple and the utilized transformer volume as the bulkiest component in a DC-DC converter. In order to provide a test bed for evaluation of the proposed models, a 50W push-pull DC-DC converter is designed and implemented. Finally, a novel cost function with three assigned weight functions is proposed in order to have a trade-off among the power loss, the output voltage ripple and the utilized transformer volume of the converter. The cost function is optimized for applications in which volume has the highest priority in comparison with power loss and ripple. The optimization results show that the transformer volume can be decreased by up to 51% and this result is verified by experimental results. The developed models and algorithms in this paper can be used for other DC-DC converter topologies with some minor modifications.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.9
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• pp.916-927
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• 2012

In the $21^{st}$ century, woman leaders are able to influence society through improved social status and economic power. From 1980-1990 there was a rapid global social development of feminism and improved media perceptions. The progression of this process is reflected by female characters in feminism films that included a new dress style. The power suit emerged in the U.S.A of the 1980s, as a dress code that showed the workplace uniform of a professional woman and spread to Korea as an influential style. This study defines the different and similar aspects in the development of women's position and the role involved in a structural background through a comparison of the socio-cultural meaning of the power suit expressed in American and Korean feminism films. For analysis, this study chose American films in the 1980s and Korean films in 1990s that fulfilled elements about feminism films. Subsequently in American feminism films, the power suit expressed an equal authority with men, strategic use of femininity according to task type, and a dissipation of symbolic effects like a rich look. In Korean feminism films, the power suit expressed an end of femininity like female transvestite, independent female images with the masculinization of appearance, and a mix of new and traditional styles.

• Journal of the Korea Safety Management & Science
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• v.8 no.4
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• pp.249-265
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• 2006

A life cycle assessment(LCA) is increasing its applicability as a powerful tool for an environmental burdens analysis. In this study, some cases are compared in terms of analysis procedures and results obtained with LCAs for evaluating power generation technologies in Korea. For the comparison, 3 power generation technologies are selected because they produces almost 90% of 2003 total electricity generation in Korea. It is shown that the range of evaluation values amounts to maximally the order of about 105, which is rather large discrepancy than the level of 101 in comparison with foreign studies. The difference seems to be due to the simplicity of modeling used in each case study. It is proposed that this large discrepancy should be obviously clarified to improve their reliability in that electricity is a essentialness for all industries and the capacity of LCA of national-level electricity affects the results of LCA for the other sectors.

• International Journal of Fluid Machinery and Systems
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• v.2 no.1
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• pp.92-101
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• 2009

The purpose of this paper is to gain a greater understanding of the performance of practical wind turbine generating systems with differing output power controllers and controlling means for wind turbine speed. Subjected wind turbines, both equipped with an asynchronous power generator, are located at two sites and are defined as wind turbine A and wind turbine B in this study, respectively. Their performance differences are examined by measuring wind speed and electric parameters. The study suggests that both wind turbines have a clear linkage between current and output power fluctuations. Comparison of the fluctuations to wind speed fluctuation, although they are triggered primarily by wind speed fluctuation, clearly indicates the specific behaviors inherent to the respective turbine control mechanisms.

• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.1-7
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• 2019

Electromagnetic measurements of the power cable tunnel were conducted from August 10 to 20, 2018, in the ${\bigcirc}{\bigcirc}$ city underground utility tunnel. During this period, the average temperature was $31.89^{\circ}C$ and the humidity was 67.56% in power cable tunnel. As a result of the electromagnetic measurement, the highest electric field was 25.3 V/m and the magnetic flux density was $42.6{\mu}T$. The average electric field was 18.56 V/m and the magnetic flux density was $29.32{\mu}T$ in the power cable tunnel. As a result of comparison with the electric equipment technical standard, the electric field in the power cable tunnel was 0.5% of the electric equipment standard and 35.2% of the magnetic flux density. It's similar value that electric field is about robotic vacuum(15.53 V/m), and magnetic flux density is similar value about capsule- type coffee machine ($23.07{\mu}T$). The number of cable lines and the size of the electromagnetic waves were not proportional to each other through comparison of cable lines in the power cable tunnel. It was confirmed that 154 kV, rather than 22.9 kV, could have a greater influence on occupational.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1212-1216
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• 2015

In this paper, we compared the performance of the Right Handed Nonlinear Transmission Line (RH-NLTL) and Left Handed Nonlinear Transmission Line (LH-NLTL) as a harmonic generator. For a performance comparison, we fabricated both a RH-NLTL and a LH-NLTL harmonic generator whose operational bandwidth is from 0.5 GHz to 1.5 GHz. Under the each condition for the RH-NLTL and the LH-NLTL to maximize second harmonic, the output power of the second harmonic was 9.33 dB lower than the input power for the RH-NLTL and 12.67 dB lower than the input power for the LH-NLTL. Under the each condition for the RH-NLTL and the LH-NLTL to maximize third harmonic, the output power of the third harmonic was 13.33 dB lower than the input power for the RH-NLTL and 14.83dB lower than the input power for the LH-NLTL. Also, we have observed that, generatlly, a RH-NLTL is useful in generating various multiple harmonics and a LH-NLTL is useful in generating a specific order of harmonic by adjusting a proper DC vias, input frequency and input power. These tendencies could be a good guideline to use NLTLs as a frequency multiplier.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.67-70
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• 2003

In this paper the main topologies of one-bit full adders, including the most interesting of those recently proposed, are analyzed and compared for speed, power consumption, and power-delay product. The comparison has been performed on circuits, optimized transistor dimension to minimize power-delay product. The investigation has been carried out with properly defined simulation runs on a Cadence environment using a 0.25-${\mu}m$ process, also including the parasitics derived from layout. Performance has been also compared for different supply voltage values. Thus design guidelines have been derived to select the most suitable topology for the design features required. This paper also proposes a novel figure of merit to realistically compare n-bit adders implemented as a chain of one-bit full adders. The results differ from those previously published both for the more realistic simulations carried out and the more appropriate figure of merit used. They show that, except for short chains of blocks or for cases where minimum power consumption is desired, topologies with only pass transistors or transmission gates are not attractive.