• Journal of Electrical Engineering and Technology
• /
• v.13 no.6
• /
• pp.2335-2343
• /
• 2018

This paper proposes an optimal damping control algorithm of the DTI (Direct Two-level Inverter) to miniaturize and reduce the weight of auxiliary power supply for railway vehicles. The conventional auxiliary power supply for railway vehicles uses a DC-DC converter to maintain the inverter input power from the line voltage smoothly. The proposed topology does not use a DC-DC converter for reducing of manufacturing and maintenance costs. It also proposes a DTI topology removed damping resistors that generate ground signal noise in a certain period. At this time, a resonance phenomenon of DC-link voltage occurs due to variation of the inductive load, and a method of controlling the resonance phenomenon of DC-link voltage is required. In order to suppress the resonance phenomenon of the DC-link voltage, at a point before resonance occurs, this paper introduces an algorithm to suppress the resonance phenomenon of DC-link voltage by compensating the resonance component of the q axis voltage of the synchronous reference frame. The proposed algorithm verifies the effect through simulation and experiment.

• Journal of Preventive Medicine and Public Health
• /
• v.50 no.4
• /
• pp.274-277
• /
• 2017

Objectives: Legionnaires' disease (LD) is a severe type of pneumonia caused by inhalation of aerosols contaminated with Legionella. On September 22, 2016, a single case of LD was reported from a newly built apartment building in Gyeonggi province. This article describes an epidemiologic investigation of LD and identification of the possible source of infection. Methods: To identify the source of LD, we interviewed the patient's husband using a questionnaire based on the Legionella management guidelines from the Korea Centers for Disease Control and Prevention. Water samples from the site were collected and analyzed. An epidemiological investigation of the residents and visitors in the apartment building was conducted for 14 days before the index patient's symptoms first appeared to 14 days after the implementation of environmental control measures. Results: Legionella pneumophila serogroup 1 was isolated from the heated-water samples from the patient's residence and the basement of the apartment complex. Thirty-two suspected cases were reported from the apartment building during the surveillance period, yet all were confirmed negative based on urinary antigen tests. Conclusions: The likely source of infection was the building's potable water, particularly heated water. Further study of effective monitoring systems in heated potable water should be considered.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.60 no.2
• /
• pp.68-71
• /
• 2011

In the case of Seoul Metro, prior to installation of platform screen doors, had seen 4~6 cases a month of mortal injuries from accidents on the platforms, including suicide attempts towards the oncoming train. However, since the installation of platform screen doors, Seoul Metro has achieved a feat of '0 mortal injuries'. In the initial stages of introducing platform screen doors domestically, due to a lack of experience in controlling platform screen doors, the products were imported and installed through technical cooperations from Japan, France and the United States. Thereafter, following investments in technologies by domestic firms, domestic production of parts such as overall control mechanism, specific control mechanism, RF devices and others were achieved. However, having installed platform screen doors in a relatively short period of time, DCU(Door Control Unit), an integral part of the whole platform screen door system, is yet to be fully domestically produced. At this moment in time, installation is being done with imported products or DCUs developed with DC motors. In this research, advantages and disadvantages of DC and BLDC motors for use in DCU will be analyzed and will produce an own BLDC controlling unit in order to solve any problems arised. Furthermore, the BLDC controlling unit produced will be integrated with DCU to improve the performance of the product and its price competitiveness.

• Asian-Australasian Journal of Animal Sciences
• /
• v.11 no.3
• /
• pp.239-244
• /
• 1998

Dried carrot meal (DCM) prepared from fresh carrot was found to be a good source of xanthophyll (54 mg/kg) and morderate source of protein (188.3 g/kg) and energy (2,510 kcal/kg) with low level of fibre (80 g/kg). DM, EE and NFE content of DCM were 895, 35 and 661.7 g/kg respectively. The ingredient was used in laying hen diet to evaluate its pigmenting value for egg yolk. Thirty-two laying hens from Starcross strain were divided into four groups and fed four different diets: a control diet containing 62% ground wheat, a corn-based diet (50% ground yellow corn), control + 4% DCM and control + 8% DCM. Use of DCM at 8% level in layer mash significantly improved yolk colour at 3rd, 6th and 9th week of supplementation in comparison with wheat-based control diet. This improvement was statististically similar to that obtained from yellow corn-based diet. DCM at 4% level also improved yolk colour score. Wheat-based diet significantly increased feed consumption compared to yellow corn and diet supplied with 8% DCM. Body weight gain, egg production, feed conversion were not significantly affected due to dietary addition of DCM and no mortality was observed during 63-day experimental period. Further works on DCM are suggested.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.3
• /
• pp.474-480
• /
• 2007

Fusarium wilt of cucumbers was effectively controlled by Escherichia coli expressing an endochitinase gene (chiA), and the rate was as effective (60.0%) as the wild-type strain S. proteamaculans 3095 (55.0%) where the gene was cloned. However, live cells of soil inoculated E. coli host harboring the chiA gene did not proliferate but declined 100-fold from $10^8$ CFU during the first week and showed less than 10 cells after day 14, suggesting that E. coli was able to express and produce the chitinase enzyme to the soil even as the population was gradually decreasing. Because the majority of the strains was alive for only a short period of time and the Fusarium-affected seedlings showed symptoms of wilting within 7-10 days, it seems that the pathogen control was decided early after the introduction of the biocontrol agent, eliminating the survival of the antagonist. These results indicated that soil inoculated E. coli could sufficiently express and produce the recombinant protein to control the pathogen, and root or soil colonization of the antagonist might not be a significant factor in determining the efficacy of biological control.

• Journal of Distribution Science
• /
• v.15 no.4
• /
• pp.5-13
• /
• 2017

Purpose - This research analyzes the effects of Korean family ownership characteristics on firm value. The positive and negative effects of family ownership on Korean firm value were analyzed. If negative effects are evident, this research explores the factors that cause a decrease in firm value. Research design, data, and methodology - The study examined a total of 5,743 companies listed on the Korea Exchange from the period 2002 to 2012 using a panel data regression analysis. Result - An empirical analysis suggests that Korean family ownership diminishes firm value. Korean family firm value has been reduced when controlling shareholders are participated in management and pursue excessive wages, or make the management entrenchment effects associated with ownership-control disparity. When the controlling shareholders of family firms have increasing control rights over the shareholders' general meeting and the directors' board, the agency costs associated with seeking increasing executive wages or private benefits reduce firm value. Conclusions - This study has significance because it reveals the negative effect of family ownership in Korea on firm value. These negative effects can be the result of agency problems from controlling family shareholders seeking excessive wages or ownership-control disparity.

• Journal of Nutrition and Health
• /
• v.31 no.5
• /
• pp.914-920
• /
• 1998

The effect of dietary pectin, tangerine pulp meal, propionate, lactate or fumarate on cholesterol (C) and triacylglycerol(TG) levels in the serum and liver, and the effect of pectin on dietary C absorption were studied in a series of three experiments. Mature female Sprague Dawley rats were fed a control diet or diets containing 5% pectin, 5% tangerine pulp meal, 3% propionate, 3% lactate 3% fumarate, or 10% pectin. Serum total C levels were lower(p<0.05) in rats fed the diet containing 5% pectin than in control rats after a 4-week feeding period(93.8 vs 119.2mg/100mL). Serum HDL, LDL+VLDL C levels were not different among diet groups. Liver total C level was also lower(p<0.05) in rats fed the diet containing 5% pectin than in control rats, but liver TG level was not influenced by diet. Dietary propionate, lactate or fumarate did not reduce serum C, indicating that propionate is not a regulator of serum C. However, dietary pectin(10%) increased fecal excretion of dietary C(or its metabolites) more than 70% over a control value. Our data indicate that dietary pectin reduces serum and liver C levels by increased fecal secretion of dietary C, but not by its fermentation product propionate or other gluconeogenic substrates. (Korean J Nutrition 31(5) : 914∼920, 1998)

• Nutrition Research and Practice
• /
• v.9 no.2
• /
• pp.150-157
• /
• 2015

BACKGROUND/OBJECTIVES: The purpose of this study was to investigate the overall effects of a tailored Dietary Approaches to Stop Hypertension (DASH) nutritional intervention program which included omega-3 fatty acids supplementation, on dietary self-efficacy, dietary knowledge, and dietary behaviors in Korean elderly women with abdominal obesity. Furthermore, we investigated the effects of the program on metabolic syndrome parameters including the antioxidant capacities in these subjects. SUBJECTS/METHODS: A randomized, controlled trial was conducted for 8 weeks. The experimental group (n = 21) received a weekly tailored nutritional program for 8 weeks and the control group (n = 18) received only one educational session. The clinical survey was conducted before and after the intervention period. RESULTS: After the intervention, dietary self-efficacy (P = 0.023), frequency of fruit intake (P = 0.019), and dietary fiber intake (P = 0.044) were higher in the experimental group than in the control group. The oxidative stress (P < 0.001) was lower in the experimental group than in the control group. Moreover, low density lipoprotein (LDL) cholesterol (P = 0.023) had significantly decreased in the experimental group but not in the control group after the intervention. CONCLUSIONS: The intervention program including omega-3 fatty acid supplementation had a positive effect on dietary self-efficacy, dietary behaviors, and oxidative stress among aged women with abdominal obesity.

• Clinical and Experimental Reproductive Medicine
• /
• v.16 no.1
• /
• pp.93-101
• /
• 1989

71 cycles of 67 women were treated for superovulation induction in our IVF & ET program from May to September in 1988. Endogenous LH surges were occurred in 21 cycles out of 71 cycles. And then, we selected 50 cycles without endogenous LH surge treated in the same period as control group. We compared egg recovery rate, egg maturity, fertilization rate, cleavage rate and pregnancy rate of study group with those of control group. We were able to detect more than 90% of endogenous LH surge by commencing daily LH monitoring on MCD 9. The egg recovery rate, egg maturity, fertilization rate, and pregnancy rate of the study group were not statistically different from those of the control group. Significantly lower cleavage rate was seen in the study group compared with that of control group. Above results suggested that the cycles with endogenous LH surge do not have to be abandoned and can be treated continuously to achieve successful pregnancy.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.6
• /
• pp.2403-2407
• /
• 2015

Background: Very few analytical studies are available on any association between stressful life events (SLE) and colorectal cancer (CRC), at least in Iran. The aim of this case control study was to determine the association between stressful life events (SLE) and colorectal cancer. Materials and Methods: This study was conducted in four hospital colonoscopy units in Tabriz city of Iran including 414 participants aged 40-75 years: 207 cases with CRC confirmed by pathology and colonoscopy findings and 207 controls free of neoplastic conditions were selected (from the same hospitals at the same period for the cases and after matching for age and sex). Stressful life events were assessed using a 43-item Holmes and Rahe Life Events Questionnaire. Multivariate logistic regression was used to estimate adjusted odds ratios for SLE and risk of CRC. Results: The stressful life event mean score in the case group was 141.3, in contrast to 63.8 in the control group (p<0.011). After adjusting for confounders, death of dear ones increased the risk of CRC (OR: 2.49; 95%CI: 1.41-5.13). Other types of stressful life events (family and husband disputes, serious occupational problems, unemployment of > 6 months, and Serious financial problems) were also associated with CRC, but without statistical significance. Conclusions: According to our findings, it seems that SLE may increase the risk of CRC.