• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.219-220
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• 2014

기존의 SRF-PLL방법은 구현이 간단하고 정상전원에서 위상각 추정 성능이 우수하지만 불평형 전원하에서 위상각 추정 성능이 저하된다. 본논문에서는 상간전압의 위상변화, 상전압의 크기변동 및 오프셋이 발생된 불평형 전원하에서 변동된 값들을 실시간으로 보상하여 위상각을 검출하는 재귀형 최소 자승법을 이용한 SRF-PLL방법을 제안한다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.695-697
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• 1993

In this paper, a novel concept for a static three-phase to three-phase power converter for an AC drive with an unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a $5{\mu}F$ ceramic capacitor in the DC link. By controlling the active power balance between two bridges, the DC link voltage can be maintained within 20V deviation from the nominal value with the small ceramic capacitor regardless of the load variation even in the unbalanced source condition.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.138-142
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• 2004

Recently over dropped frequencies of power system were recorded when power system was unbalanced between generation and demand. Therefore load following characteristic analysis of thermal and combined cycle power plant generators is necessary for low frequency condition analysis of power system. Frequency simulator supplies simulated frequency to the online generator for prescribed goal. This simulator needs to minimize effects to power system and requires stability first. This paper introduces design and manufacturing case of frequency simulator for load following characteristic analysis of generators.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.234-237
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• 2010

This paper proposes a balancing control of DC-link voltages of a H-bridge multilevel inverter for STATCOM application. Individual DC link voltage is controlled by simply adjusting the d-q voltage reference through a PI controller in each cell while the main controller carries out the reactive power control. The correctness and effectiveness of the method are validated by PSIM simulation with unbalanced load condition data taken from a typical arc furnace load, showing the adverse effects of load unbalance to DC link voltage significantly suppressed.

• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.199-204
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• 2021

We propose a dispersion-managed link with a non-midway optical phase conjugator (OPC), in which the residual dispersion per span (RDPS) of each fiber span is different for each transmission section before and after OPC. We numerically demonstrate the compensation for 960-Gb/s wavelength-division multiplexed (WDM) signals distorted by chromatic dispersion and Kerr nonlinearity of the fiber. We consider different cases for non-midway OPC, including six fiber spans - OPC - 14 fiber spans and 14 fiber spans - OPC - 6 fiber spans. The numerical results show that the compensation of the distorted 960 Gb/s WDM is more efficient when the OPC is placed after 6-th fiber span as compared to after the 14-th fiber span. Our simulation results also indicate that the compensation effect increases when the difference in net residual dispersion between both transmission sections is not large, but they are not the same. Under this condition, the larger the magnitude of the RDPSs of each fiber span, the greater the compensation.

• The Korean Journal of Community Living Science
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• v.18 no.4
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• pp.629-638
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• 2007

The aim of this study was to provide fundamental data by degree of obesity which was necessary to nutritional education for the formation of right eating and dietary guideline by researching food habits of children. In order to achieve this purpose, a survey was conducted on 3, 4, 5, 6th grade of students from 4 schools in S and G city in Jeolla-Namdo. The results was as follows. There were 384(44.4%) students were normal weight, 193(22.3) were overweight, and 287(33.2) were low weight by obesity indices. Comparing the student's subjective health condition among the degree of obesity, 40.4% of overweight recognized they were healthy, 30.1% recognized ordinary, and 57.1% of lean recognized they were healthy, 34.5% recognized ordinary. It was turned out that most students who were overweight and lean recognized healthy and normal. Family was reported to be the most impact factor on student's diet habits, and then Multimedia such as TV seemed to have a effect on overweight and lean students, but nutrition teachers had a direct influence on normal weight students. The most thing which eating habits for a reform was unbalanced diet. The students in this research have breakfast everyday and regularly. Regarding dietary attitudes, overweight group enjoyed eating healthy food more than normal and low body weight group did, and tried to eat what they have never eaten before. In conclusion, it's necessary for elementary school students that increase the control ability of self perceived health condition with education for good eating habit and grasp their condition themselves through the nutrition education in school.

• Korean Journal of Social Welfare
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• v.55
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• pp.155-179
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• 2003

This paper compares two indicators, economic development and social condition, to find a better way to measure the level of social welfare development. The results show that social condition is more adequate indicator than economic development. The social condition has high correlation with the development of social welfare in all the 78 countries as well as in five groups of countries when the economic development is controlled. The comparison of two indicators reveals important findings. Among other things, the higher the level of social condition compared with economic development, the larger the social welfare expenditure. This tendency is particularly strong among the western European countries and former socialist countries. This result implies that the macro-level policy of social redistribution is also important for the development of social welfare in addition to micro-level policy of income redistribution. As we expected, the results show that the level of Korean social welfare development is very low. Considering our levels of economic development and social condition, predicted social welfare expenditure from regression model is at least 17% of GDP, but we are spending only 30% of this predicted expenditure. Another serious problem in Korean social welfare is unbalanced expenditure between social insurance and public assistance. On the basis of these results, this paper suggests three implications for social policy to improve Korean social welfare: First of all, the gap between predicted and actual expenditures should be closed to improve the minimum level of social welfare. Secondly, the level of social condition itself should be improved to increase the public awareness of social welfare. Finally, the wide difference in expenditure between universal and selective social welfare programs should also be removed to decrease the relative deprivation of the poor.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.147-169
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• 1994

This study was conducted to ivestigate the quality of modeled chinese-cabbage Kimchi. The mutual action of sub-ingredients and optimum mixing conditions were examined by analyses of pH, acidity, content of vitamins, carotenes, number of total microorganism, and Lactobacilli, the activities of softening related to enzymes (polygalacturonase and ${\beta}$-galactosidase), and sensory quality during fermentation. The result about the mutual action of red pepler powder and garlic showed that the pH was decresed as concentration of garlic was higher and that of red peppler powder became lower. Kimchi had unpleasant taste and undesirable odor when the adding ratio of the peper powder and garlic was unbalanced. As the concentration of garlic became higher, the content of vitamin C in Kimchi tissue decreased while that of vitamin C in Kimchi juice increased. The contents of vitamin B1, B2 and carotene increased as the concentration of garlic became lower. The optimum mixing ratio of red pepper powder and garlic evaluated by overall eating quality was 4.66% and 3.45%, respectively. The result about the mutual action of ginger and green onion was that pH became higher as the concentration of ginger was 1.84% and that of green onion was 5.96%. The intensity of fresh taste and odor became stronger as the concentration of ginger increaed to 2.76% and that of green onion decreased to 2.98%. The balance of sour, salty and hot taste became better as the concentration of ginger increased and that of green onion decreased. The optimum mixing condition evaluated by overall eating quality was 2.94% in ginger ＋ 2.78% in green onion. The contents of vitamin B1, B2 and C were high in this condition. The result about the mutual action of leek and salted anchovy juice was that pH became lower as the concentration of leek increased and that of salted anchovy juice decreased. Sour, hot and sweet tastes were good in the condition of leek 12%, salted anchovy juice 4.69%. Palatable, fresh taste and odor became weaker when the one of both sub-ingredients was too much little. The optimum mixing condition evaluated by overall easting quality was 9.76% in leek ＋ 7.32% in salted anchovy juice. The contents of vitamin B1, B2, C and carotene were high in this condition and other sensory qualities were good. The result about the mutual action of salt and sugar was that pH became lower as the concentration of sugar became higher and that of salt became lower. The sweet taste was reduced of hot taste than salty taste. Palatable and fresh tastes were desirable when Kimchi fermented with less salt and more sugar. The optimum mixing condition evaluated by overall eating quality was 3.29% in sugar ＋ 4.80% in salt. The contents of vitamin B1, B1, C and carotene were high in this condition. The result of model Kimchi fermented at 20$^{\circ}C$ was that the number of Lactobacilli in model Kimchi was higher than that of in control Kimchi. The fermentation period was extended under pH 4.0 and the contents of vitamin B1, B1,C and carotene were high through the whole edible period. The activity of polygalacturonase was low, but that of ${\beta}$-galactosidase was high during fermentation.

• Journal of the Korea Fashion and Costume Design Association
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• v.9 no.3
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• pp.47-57
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• 2007

This study focused on the properties natural dyeing and natural material and on the development of functional material for well-being in apparel industry. Comus officinalis Siebold et Zuccarini is used as natural dyeing material which had been reported that have curable effect for unbalanced immunity, geriatric diseases like urinary tract system, diabetes, hypertension, arthritis, tinnitus, hyperhidrosis and women's diseases like hypermenorrhea. And this material also has anti-cancer effect so that can restraint cancer cells. 3 kinds tester of cotton, wool and silk are dyed by boiled with each dye (flower, fruits, bark of tree) as first dyeing and dried in the shade. These testers are done by post-mordanting method. Aluminium Potassium(Alk(SO4)2), Cuprie Sulfate($CuSO4{\cdot}5H2O$), Stannous Chloride($SnCl2{\cdot}2H2O$), Ferrous Sulfate($FeCl2{\cdot}4H2O$), Titanium Sulfate 24% aqueous solution(Ti(SO4)2) are used as mordants. Dyeing results of Comus officinalis Siebold et Zuccarini flower and bark are shown as yellow color series. And dyeing result of fruits is pink color series. Silk shows the best dyeing property. As the point of view for dyeing property, Ti, Sn, Fe would be the properchoice for mordant. Following results are extracted in this study. Yellow color is resulted in dyeing with Cornus officinalis flower as non-mordanting condition. Yellowish red color is come from dyeing with Comus officinalis fruit as non-mordanting condition. Grayish yellow tone is resulted in dyeing with bark as non-mordanting condition. Orange tone color with Ti-mordanting, green tone color with Sn-mordanting and gray tone color with Fe-mordanting is resulted respectively. However light-fastness of Comus officinalis(flower, fruit, bark) is very low as 1 or 2 level in non-mordanting condition, Comus officinalis flower dyeing is turned out 3 or 4 level and fruit dyeing is 4 or 5 level, bark dyeing is 2 or 3 level with Ti-mordanting respectively. Eventually Comus officinalis fruit has the best light-colorfastness property among all of dyes. dry cleaning colorfastness of Cornus officinalis(flower, fruit, bark) is good as 4 or 5 level in Ti-mordanting condition, perspiration-colorfastness of Cornus officinalis(flower, fruit, bark) is good as 4 or 5 level in Ti-mordanting condition, With these results, this study could conclude that dye-ability, colorfastness problem is getting better after mordanting process and practical usage would be possible.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1614-1627
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• 2016

The purpose of this paper is to investigate the united Electromagnetic characteristics for the effective monitoring on the static air-gap eccentricity (SAGE) of turbo-generator. Different from other studies, this paper not only studies on the unbalanced magnetic pull (UMP) and the vibration characteristics of the stator and the rotor, but also investigates the harmonic features of the magnetic flux density and the circulating current inside the parallel branches (CCPB). The theoretical calculation, together with the finite-element-method (FEM) simulation and the experiment verification, is taken for a SDF-9 type non-salient generator. It is shown that, when SAGE occurs, apparent double-frequency UMP and vibrations will be produced both on the stator and the rotor, while the CCPB will have an obvious increment at the $1^{st}$ harmonic component. In addition, the amplitude of the magnetic flux density will be of cosine distribution in the circumferential position of the air-gap, while in normal condition it is a constant. Moreover, the pass-band amplitude, together with the $1^{st}$ harmonic of the magnetic flux density, will be enlarged as well. These united electromagnetic characteristics can be used as the diagnosis and monitoring criterion for SAGE.