• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.4
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• pp.353-358
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• 2012

In this paper, three-phase power equalizing system (PES) with UPS function is proposed. This system is based on NiMH battery with battery management system. The power conversion circuit is composed with the three-phase converter/inverter, the bi-directional converter, and the thyristor switches. The three-phase converter/inverter provides the power to the grid or get the power from the grid. Also, it operates as a UPS. The bi-directional converter charges or discharges the battery. The thyristor switches are used for connecting/disconnecting with the grid and the load. A 15 kW prototype is implemented for the verifying the performance of the proposed system.

• Journal of Biosystems Engineering
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• v.35 no.6
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• pp.413-419
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• 2010

Plant growth was greatly affected by the spectral distribution and light intensity of artificial lighting sources. In this study, the spectral characteristics of high power sodium (HPS) lamps and metal halide (MH) lamps produced by three different manufacturers were measured. Even though the spectral distribution of HPS lamps with lamp wattage of 250 W and 400 W was very similar, but the spectral light intensity by the manufacturers was different. Difference in the spectral light intensity of MH lamps by the manufacturers was increased with the increasing lamps wattage. Light intensity at the region of blue (B), green (G), red (R) and far-red (FR) light of HPS and MH lamps was also analyzed. HPS lamps showed the light intensity in order of R, FR, B and G light. The ratio of G, B, R and FR to photosynthetic photon flux (PPF) of HPS lamps with the lamp wattage of 250 W was 3.0-3.2%, 5.5-5.9%, 17.3-19.2% and 6.5-7.8%, respectively. For MH lamps, it showed the light intensity in order of R, FR, B, and G. The ratio of B, G, R, and FR to PPF of MH lamps with 250 W was 14.0-15.5%, 22.6-27.5%, 7.5-9.5% and 2.7-4.2%, respectively. HPS and MH lamps with 400 W had a relatively smaller ratio of R and FR to PPF than those with 250 W. HPS lamps showed that the ratio of light intensity of B and FR to R was 0.15-0.28 and 0.36-0.4, respectively. For MH lamps, the ratio of light intensity of B and FR to R was 1.26-2.72 and 0.27-0.56, respectively. From these results, it was concluded that the portion of blue light of MH lamps was higher than those of HPS lamps.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.132-137
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• 2008

This experiment was conducted to investigate the effect of supplemental lighting of low light intensities on growth and yield of rose 'Vital' in a forcing culture. Metal halide lamp (MH), High pressure sodium lamp (HSP), and MH+HSP were used as the light sources, and they were set up at a $310\;cm{\times}450\;cm$ interval and at 120cm above the culture beds. Light intensity at 1m point distance from supplemental lighting sources was $32{\sim}34\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Days to the 1st and 2nd harvests decreased by $5{\sim}8$ and $3{\sim}5$days, respectively in supplemental lighting treatment as compared to the control. Days to harvesting was the shortest in MH+HPS treatment, followed by BPS and MH, although there was no significant difference between HPS and MH treatments. The growth was better and incidence of blind shooting decreased by $5{\sim}7%$ in supplemental lighting treatments than the control, increasing marketable cut flowers. The incidence of blind shoot was the lowest in MH+BPS treatment, and there were no significant difference between MH and BPS treatments. In conclusion, supplemental lighting of low light intensities was effective in reducing days to flowering and reduced occurrence of blind shoots.

• Korean Journal of Child Studies
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• v.17 no.1
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• pp.245-258
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• 1996

The purpose of this study was to examine the relationship between mother's parenting stress and child's temperament, mother's temperament, and poorness-of-fit. The subjects were 236 mothers of 4- to 6-year-old children in Seoul. Data was analyzed by correlation, analysis of variance, and stepwise regression analysis. Results showed that most poorness-of-fit of emotionality was due child's high-mother's high (CH-MH) and high-low (CH-ML) combination. Most poorness-of-fit (activity as well as sociability) was associated with child's low-mother's low (CL-ML) and low-high (CL-MH) combination. Mothers who had a highly emotional child and who were in poorness-of-fit emotionality perceived more hassles and more intensive daily parenting stress. It was also found that the most significant variable predicting mother's hassles and daily stress intensity was poorness-of-fit of emotionality, followed by mother's emotionality.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.79-85
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• 2016

In this study, we proposed a new single-stage small power MH lamp electronic ballast and power-factor correction circuit with improved circuit by the current of passive power factor correction. Main circuit integrates traditional DC/DC and DC/AC circuits into one-stage DC/AC inverter. Moreover, we described the working principle and control strategy of the new circuit; it's soft switching principle; and resonant element parameter design formula. An experimental prototype of HID lamp electronic ballast with output power of 70 W was built to verify the feasibility of the analysis and design. The simulation and experimental results proved that the power factor of this circuit could reach 94%, with efficiency of 90%. The input current harmonics conform to IEC 61000-3-2 standards and its cost is low. These superior performances of the new circuit indicate certain practical values.

• Transactions of Materials Processing
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• v.17 no.3
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• pp.170-181
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• 2008

The shape of rectangular cup used for Ni-MH(Nickel-coated Metal Hydrogen) battery for hybrid car looks quite simple, but the forming process of extruding and setting up process design are highly difficult. Furthermore, there are few concrete reports on the rectangular deep drawn cup as part of hybrid vehicles till now. In this study, process design for rectangular cup in the multi-stage deep drawing process is carried out, and FE analysis is also preformed based on the result of the process design. From the simulation result, some unexpected problems such as earing, wrinkling and excessive thickness changes of the intermediate blank occurred. To overcome these failures, a series of modification for punch shape in the forming process design are completed and applied. Considering the modified punch shape in the multi-stage deep drawing process, additional FE analysis is also carried out and the simulation result is verified in view of the deformed shape, thickness change and effective strain distribution. The result of FE analysis with the improved process design confirmed not only reducing thinning of wall and possibilities of failure but also improving the quality of drawing product through the modification of punch shape.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.8.1-8.5
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• 2020

Background: The cause of maxillary growth restriction in patients with cleft lip and palate remains controversial. While studies have investigated the effects surgical technique and timing have on maxillary growth, few focus on patients with isolated cleft palate (ICP). The purpose of this study was to determine the impact palate repair and its associated complications may have on maxillary growth. Methods: A retrospective chart review of ICP patients who underwent palatoplasty from 1962 to 1999 at Akron Children's Hospital was performed. Patient demographics, Veau type, age at primary repair, closure technique, presence of fistula or velopharyngeal insufficiency (VPI), number of palatal operations, maxillary hypoplasia (MH) frequency, and follow-up were recorded. Exclusion criteria included patients with cleft lip, submucous cleft, or syndromes. Results: Twenty-nine non-syndromic ICP patients were identified; 62% (n = 18) had Veau type 1 and 38% (n = 11) had Veau type 2. All patients underwent 2-flap or Furlow palatoplasty with mobilization of mucoperiosteal flaps. Vomerine flaps were used in all Veau 2 cleft palate closures. Palatoplasty was performed at a mean age of 19.9 ± 8.2 months. Average follow-up was 209 ± 66.5 months. The rate of VPI was 59% (n = 17) and the rate of oronasal fistula was 14% (n = 4). Conclusions: There was a low incidence of MH despite complications after initial palate closure. Our results seem to suggest that age at palate closure, type of cleft palate, and type of surgical technique may not be associated with MH. Additionally, subsequent procedures and complications after primary palatoplasty such as VPI and palatal fistula may not restrict maxillary growth.

• Review of KIISC
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• v.4 no.2
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• pp.5-17
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• 1994

전자 우편 시스템은 컴퓨터와 네트워크를 이용하는 이용자들이 가장 빈번히 사용하고 있는 서비스 중의 하나로서 그 이용률은 매년 급증하고 있으며 이와 더불어 교류되는 정보에 대한 보호 및 안전성에 대한 요구도 제기되고 있다. 본 고에서는 이러한 전자 우편 시스템에 보호 서비스를 제공하기 위한 여러 제안된 방식들중에 X.400 MHS과 Internet의 PEM(Privacy Enhanced Mail),미국의 SDNS MSP(Message Secure Protocol)에 관하여 각각의 보호 서비스 제공 방식과 보호 서비스의 유형, 범위, 특성들을 논의하며 이들 접근 방식간의 관련성과 차이점들을 분석하고자 한다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.1
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• pp.3685-3701
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• 1975

This study was conducted to investigate the strength of soil cements for varied molding water content and cement content(3,6,9,12%) in four cementstabilized soils(KY: sand, MH: sad, SS: sandy loam, JJ: loam). The eoperimental results obtainedfrom unconfined compressive strength tests are asfollows: 1. The optimum moisture content increased in accordance with the increase of the cement while maximum dry density didn't change uniformly. 2. The moisture content for maximum strength was higher than the optimum moisture content in the higher cement content. Moisture-density curves showed a dull peak in the higher cement contents, on the other hand, a sharp peak in the lower cement contents. 3. In molding the specimen with the approximate optimum moisture content, the maximum strength showed at the wet side of the optimum moisture content. 4. SS and JJ maybe used as cement-stabilized base of road to require 300PSI of compressive strength cured seven days, but MH and KY may be not adequate. 5. In soil cement, the better the grain size distribution was, the stronger the compressive strength was itn general. 6. The relation between 28-day strengh and 7-day strength in the cementstabilized four soils may be expressed as follows: q28=1.55q7+1.5 in which q28:28-day strength. q7:7-day strength.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.62-66
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• 2006

In this work, the properties of environmentally friendly functional panel made from waste aluminum were investigated. Product quality enhancement was pursued through an improved viscosity process, a mixing process by agitating, a foaming process, a cooling process, and a color addition process. An acoustic transmission attenuation test, a sound adsorption rate measurement test, and a foaming condition and scrap mixing test were implemented. As a result, the functional panel made from waste aluminum was ultra lightweight and had excellent properties such as soundproof, sound interception, and shielding harmful electromagnetic waves. Also, the functional panel showed low thermal conductivity (about 2.2 kcal/mh) and excellent heat-insulating property.