• Journal of Power Electronics
• /
• v.18 no.5
• /
• pp.1458-1469
• /
• 2018

This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT2Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the $3LT^2Is$ can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.1
• /
• pp.16-22
• /
• 2014

This study was conducted to determine the changes in soil chemical properties and the growth of seedling according to the different dredged soil improving methods at slope of Saemangeum sea dike. Undersea dredged soil was improved by five different methods. Seedlings of Ulmus davidiana var. japonica, Chionanthus retusa, Celtis sinensis, and Pinus thunbergii were planted after 9 month of experience site installation, then soil pH, NaCl concentration in soil, soil organic matter (SOM), and survival rate and height of seedling was measured. Initial soil pH was highest in the control plot but it decreased to the similar level with other soil improving plots after 35 months. There were no differences in NaCl concentration between the control and soil improving plots, and it showed decreasing tendency during the study period. In the control plot, initial SOM was lowest among that of other plots during the study period. The survival rate of 36 months after planting of P. thunbergii was highest among the species. The gap of the tree growth of P. thunbergii between the control plot and the soil improving plots was small, however, other species showed relatively higher tree height in the soil improving plots than the control plots. Creation forest with P. thunbergii might be a cost effective afforestation in coastal reclaimed land since it rarely needs additional improvement of dredged soil.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.20 no.4
• /
• pp.265-274
• /
• 2000

To investigate the effects of anion replacement on NO3- concentration in Italian ryegrass. Plants weregrown hydroponically to the full vegetative stage. NO3 supply(control) was replaced with SO1- (Tl), C1-(T2) and water (T3) to during 14 days. The determination of inorganic nutrient uptake and quantification ofprincipal metabolites (nitrate. protein and sugar) followed. Relatively high uptake of ~ a a'n d Ca" for controlplants, K+ and POJ- for T2 plants, and C 1 for TI plants was observed, respectively. Proteins in shoot andstubble were relatively higher in control and TI plants, which coupled N source. In root proteins largelydecreased (especially in T3 plants) during experimental period. Sugars in shoot of all four treatments tendedto decrease during the first 7 days and recovered afterward. Sugars in stubble also markedly decreased duringthe first 7 days, while those in root was much less varied during experimental period. After 14 days oftreatment, nitrate concentration in shoot of control plants was 13mgIg FW. Comparing to control: nitrate inshoot reduced by 27%, 46% and 50% in TI, T2 and T3 plants, respectively. Dry weight was slightlyincreased or not significantly changed in control, T1 and T2 plants, while a significant decrease(31.3% ofcontrol) occurred in T3 plants.(Key words : Italian ryegrass, Anion replacement, Ion uptake, Protein, Sugar, Nitrate)ptake, Protein, Sugar, Nitrate)

• Women's Health Nursing
• /
• v.8 no.3
• /
• pp.371-379
• /
• 2002

The purpose of the present study is to consider its effect on the childbirth of a woman. This is a quasi-experimental study with nonequivalent control group post-test design. The subjects of this study are 60 primiparas (30 in the control, and another 30 in the experimental group) who have had a regular prenatal care from February 5 to March 20, 2002, in an outpatient obstetrics and gynecology of S university medical center located in Seoul. The result is as follows: 1. The hours of labor pains in the entire delivery period: the average hours are 7 hr. 9 min. in the experimental group, and 10 hr. 39 min. in the control group. The hours of labor pains are shorter in the woman with a family delivery experience in LDR. The difference is statistically significant (t=-3.34, p=.001). 2. The degree of pains in the entire delivery period: the average degree is 7.38 in the experimental group, and 7.68 in the control group. The degree of labor pains are lower in the woman with a family delivery experience in LDR. But, the difference is statistically insignificant (t=-0.86, p=.396). 3. The perceptions of the delivery experience: the average score of the perception is 73.63 in the experimental group, and 63.57 in the control group. The women with a family delivery experience in LDR have more positive perception of the delivery procedure, and, the difference is statistically significant (t=4.65, p=.000). In summary of the above result, a family-participated delivery in LDR is proved to be an effective nursing intervention that shortens the hours spent in the delivery procedure and promotes positive perceptions of the delivery experience.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.3
• /
• pp.403-408
• /
• 2005

This study investigated the effects of chromium propionate on growth performance, serum traits and immune response in weaned pigs. Twenty-four 4 wk-old crossbred weanling pigs (initial body weight about 9.52${\pm}$0.48 kg) were randomly allotted into one of two groups, a control group (basal diet), chromium propionate group (diet supplemented with 200 ${\mu}g$ $kg^{-1}$ (ppb) of chromium propionate). This experiment was conducted over nine weeks. Escherichia coli lipopolysaccharide (LPS) 100 ${\mu}g$ $kg^{-1}$ BW was used as the stress-inducing agent in the middle (4 wks) and final (8 wks) periods. The experimental results indicated that chromium propionate had no effect on growth performance (p>0.05). Chromium propionate supplementation reduced the percentage of LDL+VLDL (low and very low-density lipoprotein) and increased HDL (high-density lipoprotein), but did not affect other serum traits. Pigs supplemented with chromium propionate had higher antibody titers specific for sheep red blood cells (SRBC) and serum total globulin relative to the control during the final period (p<0.05). A challenge with LPS increased white blood cells in the chromium propionate group in both experimental periods (p<0.05). The chromium propionate group exhibited higher IgG and $\gamma$-globulin than the control during the middle experimental period (p<0.05). Moreover, the PHA (phytohemagglutinin) challenge result in the chromium propionate group was better than the control group (p=0.056). Greater neutrophil activity was displayed than in the control (p<0.05). This suggests that chromium propionate supplementation benefited the weaned pigs in lipoprotein and immune response.

• Journal of Nutrition and Health
• /
• v.21 no.5
• /
• pp.295-304
• /
• 1988

To study effect of dietary polyunsaturated fatty acid and $\omega$-tocopherol content on lipid peroxidation in rat liver, rats were fed for 3, 6 and 9 weeks with normal tocopherol diet added 40mg of DL-$\alpha$-tocopherol/kg of diet (PF group), high tocopherol eit 200mg of DL-$\alpha$-tocopherol/kg of diet(PFE group), low tocopherol diet without addition of DL-$\alpha$-tocopherol to diet(PFO group), and control diet added 40mg of DL-$\alpha$-tocopherol/kg of diet(control group). Each diet group supplied 45% of total calorie from corn oil except control group which supplied 12% of total calorie from corn oil. After each feeding period, lipid peroxide and tocopherol contents were measured in the liver as well as activities of glutathione peroxidase and superoxide dismutase. PF group had almost the same contents of liver peroxide, tocopherol contents and activities of glutathione peroxidease and superoxide dimutase as control group, while PFE group had higher tocopherol content and glutathione peroxidase activity and lower lipid peroxide contents and superoxide dismutase activity than control group. On the other hand, changes in the values of PFO group were opposite to those of PFE group. Differences in the values among groups were more pronounced as feeding period became longer.

• Journal of Korean Academy of Nursing
• /
• v.34 no.3
• /
• pp.440-448
• /
• 2004

Purpose: This study was to evaluate the effects of a physical activity reinforcement program on exercise compliance, depression, and anxiety in continuous ambulatory peritoneal dialysis(CAPD) patients. Method: A nonequivalent control group with a pre-post test was designed. Data collection was done from December, 2002 to June, 2003 at a hoapital. The degree of depression and anxiety of the patients was assessed by the score of SCL-90-R, and exercise compliance was measured by exercise period, frequency, time and intensity. The experimental group was composed of 19 participants who were educated based on an exercise education protocol and carried out walking exercises two to four times a week after hearing verbal persuasion biweekly through the telephone or a face-to-face interview for 12 weeks, while 17 participants in control group received no intervention. Result: 1. The experimental group showed significant improvement in self-efficacy of exercise compliance (U=79.00, p=.01), exercise period ($x^2$=20.84, p=.00), exercise frequency ($x^2$=9.03, p=.0l), exercise time ($x^2$=9.03, p=.0l) and exercise intensity ($x^2$=11.09, p=.00) compared to those of the control group. 2. The experimental group showed a lower depression score (U=84.50, p=.01) than the results of the control group. 3. However, there were no changes in anxiety level compared to the control group. Conclusion: The physical activity reinforcement program was found to have an effect on exercise compliance and the depression score of CAPD patients. The results provided evidence for the importance of physical activity and verbal persuasion in CAPD patients.

• Journal of Korean Home Economics Education Association
• /
• v.13 no.3
• /
• pp.119-130
• /
• 2001

The purpose of this research is to discover how Practical Reasoning Home Economics Instruction(PRHEI) applied to food and nutrition units would impact on the morality of female high school students. The research sample was drawn from the two freshman classes of \"M\" High School far Girls. located in the Pusan area. One classroom of 50 students was used as the test group and the other of 47 as the control group for the total of 97 students. Measuring the intellectual and behavioral morality scores followed the pre-post test design under which the PRHEI was administered to the test group during the period of eight weeks in a semester. Whereas the control group received the conventional lecture-oriented instruction during the same period. The effects of PRHEI on morality were measured using the system developed in 1972 by Ontario Institute for Studies in Education. and translated by Kim. Ahn-Jung in 1982. The system developed by Yang. Byung-Han in 1994 was utilized to measure the behavioral morality score. In analyzing the collected data. SPSS/WIN was used to generate means standard deviation and t-test. The research findings are as follows : First. The students who have been taught under the PRHEI score higher on the intellectual morality scale than the control group receiving the lecture-oriented instruction. Second. The test croup students do not show any notable differences from the control group students receiving the lecture-oriented approach on the behavioral morality scale; however, the former do show statistically significant differences from the latter in the sub-factor of honesty scoring higher means over the control group.

• Journal of the Korean Home Economics Association
• /
• v.18 no.4
• /
• pp.95-101
• /
• 1980

This study was carried out to investigate the effect of the diet supplemented with various amounts of ginseng powder on the growth rate and blood glucose level in rat. Male Albino rats, weighing between 90 to 100g, were divided into 5 diet groups of 6 rats each. experimental diets contained 0, 2, 4, 6 and 8% ginseng powder which was substituted for rice powder and were designated C, G-2, G-4, G-6 and G-8, respectively. The diets were fed for 3 weeks. Throughout feeding period, feed consumption, body weight, feed and protein efficiency ratios were measured, organ weights and blood glucose level were determined at the end of the experimental period. the results are summarized as follows. 1. rats in G-2 group consumed the highest amount of diet among all groups. 2. Body weight gain was significantly higher in G-2 and G-4 than in other groups. 3. Feed and protein efficiency ratios were a little higher in G-4 than in control group. And those of group G-8 were the lowest among those of other groups. 4. The weight of liver was significantly lower I G-4 than in control group. The weight of kidney was significantly lower I G-4 and G-8 than in control group. The weight of heart was significantly lower I G-4 and G-8 than in control group. While, the weight of spleen was greater in ginseng powder diet than in control group. 5. Supplementing ginseng powder in diet resulted in deceased nitrogen in liver. 6. Blood glucose was decreased with increased level of ginseng powder diet.

• Korean Journal of Poultry Science
• /
• v.23 no.3
• /
• pp.121-128
• /
• 1996

A feeding trial was conducted to evaluate the effect of supplementing MAXIMINERAL(72)(MM), a cornmercial product of Ca, Mg-bentonite, to the broiler diet. One thousand hatched rnale broiler chickens(Cobb strain) were randomly assigned to 4 dietary treatments; MM 0% (control), MM 1%, MM 2%, and MM 2% + tricalciurnphosphate (CaP) 0.5%. Each treatment had 5 replicates of 50 birds each. Birds were grown on floor and fed ad libitum for 5 wk. Through the whole period, weight gain and feed intake were not significantly different among treatments. However, weight gain of MM 2% + CaP 0.5% group was highest and orthogonal contrast showed that the feed intake during the period of 0~2 wk was significantly(p<0.01) lower in MM supplemented groups than the control. Feed efficiency (feed /gain) of MM supplemented groups were significantly better than the control. Feed efficiency of the control was significantly(p<0.05) higher than MM 1% and MM 2% + CaP 0.5% groups but not different from MM 2% group. Contents of ash, Ca and P of tibia were not significantly different among treatments but that of P tended to be low in MM 1% and MM 2% groups. There were significant (p<0.01) differences in plasma alkaline phosphatase (AP) activity among treatments. The highest AP activity was shown in MM 2% + CaP 0.5% group followed by the control, MM 2% and MM 1% group. It was concluded that supplernentation of MM at the level of 1% of broiler diet significantly improves feed efficiency and adjustment of P level rnay further improve the performance of the broiler chickens.