• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1863-1873
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• 2024

In the Korean domestic nuclear industry, to analyze the reliability of instrumentation and control (I&C) systems, the failure rates of the electronic components constituting the I&C systems are predicted based on the MIL-HDBK-217F standard titled 'Reliability Prediction of Electronic Equipment'. Based on these predicted failure rates, the mean time to failure of the I&C systems is calculated to determine the replacement period of the I&C systems. However, this conventional approach to the prediction of electronic component failure rates assumes that factors affecting the failure rates such as ambient temperature and operating voltage are static constants. In this regard, the objective of this study is to propose a prediction method for the remaining useful life (RUL) of electronic components considering mean time to failure calculations reflecting dynamic environments, such as changes in ambient temperature and operating voltage. Results of this study show that the RUL of electronic components can be estimated depending on time-varying temperature and electrical stress, implying that the RUL of electronic components can be predicted under dynamic stress conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.41-46
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• 2010

It has been shown that orexin has an inhibitory effect on gonadotropin secretions in non-ruminant animals. The goal of this study was to determine whether orexin affects LH, and FSH secretions in the camel, as a pseudo-ruminant animal, under different dietary energy content. Sixteen castrated camels were randomly divided into 4 groups. Animals in groups 1 and 2 were fed 100% and animals in groups 3 and 4 were fed 50% energy content in their diet for 20 days. After 20 days, animals in groups 1 and 3 received infusions of 1 $\mu{g}$ orexin and groups 2 and 4 received infusions of 2 $\mu{g}$ orexin into their jugular vein. Blood samples were collected from the jugular vein every 20 minutes from 4 h before the first infusion of orexin until 4 h after the last orexin infusion. Lower dietary energy intake and infusions of 2 $\mu{g}$ but not 1 $\mu{g}$ orexin significantly (p<0.01) decreased the mean plasma concentrations and pulse amplitudes of LH of the animals. Infusion of 1 and 2 $\mu{g}$ orexin did not change the secretions of LH of the animals fed NE. Different energy dietary intake and infusion of 1 and 2 $\mu{g}$ orexin did not change the mean plasma concentrations of FSH of the animals in all groups. Infusions of 1 and 2 $\mu{g}$ orexin significantly (p<0.01) decreased the glucose levels of animals fed LE but not in NE fed animals. Additionally, plasma glucose levels of the LE-fed animals in groups 3 and 4 were significantly (p<0.01) lower than those of the animals in groups 1 and 2 fed NE diet. The results of this experiment indicated that orexin may negatively affect LH and FSH in camels with negative energy balance, but not in those with positive energy balance.

• Asian-Australasian Journal of Animal Sciences
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• 제15권3호
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• pp.330-339
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• 2002

Fifty one Nili-Ravi dairy buffaloes in their last two months of gestation were selected. After parturition, rectal examination of reproductive organs was carried out until the occurrence of the first oestrus (PEI). Milk samples were analyzed for milk progesterone levels (MPL). Ovulation (POI) was confirmed by rectal palpation and MPL. Feed and blood samples were collected fortnightly and analyzed. Body condition score (BCS) was recorded on a scale of 0 to 5. Crude protein (CP) intake varied among different seasons and correlated positively with serum urea levels, POI (p<0.01) and PEI (p<0.05). Excess CPI was lower in the group showing oestrus as compared to those remaining as anoestrus (p<0.05). The dietary ratio of crude protein - metabolizable energy (CP:ME) in the oestrus animals was narrow and constant, while the anoestrus animals had a widely fluctuating one. In normal breeding season (NBS) calvers, mean serum urea level (SUL) was lower than the low breeding season (LBS) calvers. SUL was positively correlated with PEI and POI (p<0.01). Up to six months postpartum, SUL were constantly higher in anoestrus than oestrus buffaloes. Mean metabolizable energy (ME) intake was lower in the NBS calvers than the LBS calvers (p<0.01). BCS and postpartum ovulation interval were correlated with ME intake (p<0.01). Prepartum ME intake was higher in oestrous as compared to anoestrous animals (p<0.05). Higher and lower ME intakes were associated with anoestrus, while a moderate energy intake was associated with a PEI of less than 75 days. Buffaloes with poor BCS belonged to the LBS calving group and most of the NBS calving buffaloes had good BCS. BCS was negatively correlated with PEI (p<0.01) and was higher in oestrous buffaloes than anestrus. It was concluded that excess intake of crude protein, associated with higher serum urea levels and low energy intake, associated with poor body condition, are the key factors for low reproductive efficiency. It may be corrected by adopting a proper feeding strategy.

• 한국태양에너지학회 논문집
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• 제35권5호
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• pp.39-48
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• 2015

In this study, the solar chimney, one of the passive solar systems, is proposed as a method to improve the thermal environment of northern zones in buildings. As this well-known system has rarely been used in building projects, an adequate application of the system is proposed in this paper: the solar chimney system is designed to meet the required ventilation rate and consequently to reduce the ventilation load in the northern part of a building. To investigate such a possibility, a numerical model for the system is developed, and results of numerical tests are used for energy simulations. The results were taken into account for test simulations in EnergyPlus. As a result, approximately 75% of the volumetric ventilation rate required in the north zone could be supplied with the air volume acquired through the system and the monthly mean load was reduced by 29.5%, from 1.584 kWh to 1.117 kWh. The analyses of hourly mean heating and ventilation load over the heating period indicated that the system was very effective at around 13:00. Results show that 33% reduction in the ventilation load and 17% in the heating load for the north zone could be acquired through this system.

• Nutrition Research and Practice
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• 제6권5호
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• pp.458-465
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• 2012

This study aims to determine the association between obesity-related behaviors (dietary practices, physical activity and body image) and body weight status among adolescents. A total of 382 adolescents (187 males and 195 females) aged 13 to 15 years in Kajang, Selangor participated in this study. Majority of the respondents were Malays (56.0%), followed by Chinese (30.1%) and Indians (13.9%). Dietary practices, physical activity and body image of the adolescents were assessed through the eating behaviors questionnaire, two-day dietary record, two-day physical activity record and multi-dimensional body image scale (MBIS), respectively. Body weight and height were measured by trained researchers. The prevalence of overweight and obesity (19.5%) was about twice the prevalence of underweight (10.5%). About two-thirds of the respondents (72.3%) skipped at least one meal and half of them (56.2%) snacked between meals with a mean energy intake of $1,641{\pm}452$ kcal/day. More than half of the respondents (56.8%) were practicing sedentary lifestyle with a mean energy expenditure of $1,631{\pm}573$ kcal per day. Energy intake (r = 0.153, P < 0.05), physical activity (r = 0.463, P < 0.01) and body image (r = 0.424, P < 0.01) were correlated with BMI. However, meal skipping, snacking and energy expenditure per kg body weight were not associated with body weight status. Multiple linear regression analysis showed that body image, physical activity and energy intake contributed significantly in explaining body weight status of the adolescents. In short, overweight and obesity were likely to be associated not only with energy intake and physical activity, but also body image. Hence, promoting healthy eating, active lifestyle and positive body image should be incorporated in future obesity prevention programmes in adolescents.

• Journal of Preventive Medicine and Public Health
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• 제17권1호
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• pp.289-294
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• 1984

The energy expended while playing tennis was determined from the players heart rate and from the amount of oxygen they consumed. This study was made using eight healthy but unathletic male college students. Expired air was collected for 2 minute periods during each game by the Douglas bag method. Samples were collected when serving and receiving. The air collected was measured using a wet test gas meter. The amount of air collected was expressed in STPD. Oxygen consumption was determined by measuring the oxygen content of the expired air with a Orzat gas analyzer. The energy expended during the tennis games was calculated indirectly. The caloric coefficient of oxygen was multiplied by the volume of oxygen consumed. The caloric coefficient of oxygen varied from 4.6 to 5.1 kcal/liter of oxygen. In this study the value of 5 kcal/liter of oxygen was used in the calculations. The accuracy of the measurements of energy expended was tested using regression analysis of the measured volume of oxygen. The mean values of heart rate, oxygen consumed and energy expended did not vary when the activity of serving and receiving was compared. The mean value of oxygen consumed during play was $1.4329{\pm}282ml/min$ or $21.6{\pm}4.0ml/kg/min$. The energy expended was $7.15{\pm}1.46kcal/min$ or $6.45{\pm}1.23kcal/kg/min$. The values were equivalent to 5.5 mets. When the levels of oxygen consumed were estimated using the formulas, they were found to be higher than the measured levels. The estimated amounts, however, were within 25% of the measured amounts.

• 한국통신학회논문지
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• 제35권7C호
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• pp.604-610
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• 2010

본 논문에서는 기존의 CLSFN (Cepstral distance and Log-energy based Silence Feature Normalization) 방법의 인식성능을 향상시키기 위하여, 필터 뱅크 서브 밴드 영역에서 잡음을 차감하는 방법과 CLSFN을 결합하는 방법, 즉 FSFN (Filter bank sub-band energy subtraction based CLSFN)을 제안하였다. 이 방법은 음성으로부터 특징 파라미터를 추출할 때 필터 뱅크 서브 밴드 영역에서 잡음을 제거하여 켑스트럼 특징을 향상시키고, 이에 대한 켑스트럼 거리를 이용하여 음성/묵음 분류의 정확도를 개선함으로써 기존 CLSFN 방법에 비해 향상된 인식성능을 얻을 수 있다. Aurora 2.0 DB를 이용한 실험결과, 제안하는 FSFN 방법은 CLSFN 방법에 비해 평균 단어 정확도 (word accuracy)가 약 2% 향상되었으며, CMVN (Cepstral Mean and Variance Normalization)과의 결합에서도 기존 모든 방법에 비해 가장 우수한 인식성능을 나타내어 제안 방법의 유효성을 확인할 수 있었다.

• 대한영양사협회학술지
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• 제15권1호
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• pp.52-68
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• 2009

This study compared activity factor. predicted resting metabolic rate (RMR), and nutrient intakes between athletic and non-athletic high school students in Gangwon-do. Fifty soccer players (30 males and 20 females; mean ages 16.7${\pm}$1.0 years and 16.4${\pm}$1.1 years. respectively) and 50 non-athletic (30 males and 20 females: mean ages 17.5${\pm}$0.4 years and 16.4${\pm}$1.1 years respectively) high school students were included. Anthropometric measurements included: weight and height. triceps skinfold, mid-ann circumference, and body fat. Prediction equations consisted of those from the Harris-Benedict. FAO/WHO/VNU, IMNA, Cunningham, Mifflin et al., and Owen et al. A one-day activity diary was collected by interview, and the 24-hour recall method was used to analyze nutrient intakes of subjects. The activity factors of the male and female athletic groups (2.23 and 2.16, respectively) were significantly higher than those (1.52 and 1.46, respectively) of the non-athletic group. There was only a significant difference in RMR by use of the Cunningham's equation between two groups. For the males. almost all nutrient intakes of the athletic group (except carbohydrate, iron, vitamin $B_1$, $B_6$, and niacin) of athletic group were significantly higher than those of the non-athletic group. The female athletic group showed significantly higher nutrient intakes with the exception of most vitamins. These results suggest that assessments of energy balance between energy intake and energy expenditure by employing RMR and activity factors would be useful to prevent and treat obesity in high school athletes. In addition, the Cunningham's equation would be appropriate for predicting their energy needs.

• 한국대기환경학회지
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• 제19권3호
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• pp.285-296
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• 2003

The measurement of the radiation energy, trunk temperature, leaf area index (LAI), air temperature, vapor pres-sure, and precipitation has been conducted under a mixed forest at Kwangneung Arboretum during the period of 2001. Characteristics of the diurnal and seasonal variation of the radiative energy were investigated. The aerodynamic roughness length was determined as about 1.6 m and the mean albedo was about 0.1 The downward short-wave radiation was linearly correlated with the net radiation and its correlation coefficient was about 0.96. From this linear relation, the heating coefficient was calculated and its annual mean value was about 0.21 The albedo and heating coefficient was varied with season, surface characteristics, and meteorological conditions. The diurnal and seasonal variations of radiation energy were discussed in terms of the surface characteristics and meteorological conditions. In the daytime, during clear skies, net radiation was dominated by the shortwave radiation. In presence of clouds and fog, the radiation energy was diminished. At night, the net radiation was entirely dominated due to the net longwave radiation. There was no distinct diurnal variation in net radiation flux during the overcast or rainy days. The net radiation was strongest in spring and weakest in winter. The seasonal development in leaf area was also reflected in a strong seasonal pattern of the radiation energy balance. The timing, duration, and maximum leaf area and trunk temperature were found to be an important control on radiation energy budget. The trunk temperature was either equal or warmer than air temperature during most of the growing season because the canopy could absorb a substantial amount of sunlight. After autumn (after the middle of October), the trunk temperature was consistently cooler than air temperature.

• Clinical and Experimental Emergency Medicine
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• 제3권3호
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• pp.148-157
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• 2016

Objective Our aim was to compare the compression quality, exercise intensity, and energy expenditure in 5-minute single-rescuer cardiopulmonary resuscitation (CPR) using 15:1 or 30:2 compression-to-ventilation (C:V) ratios or chest compression only (CCO). Methods This was a randomized, crossover manikin study. Medical students were randomized to perform either type of CPR and do the others with intervals of at least 1 day. We measured compression quality, ratings of perceived exertion (RPE) score, heart rate, maximal oxygen uptake, and energy expenditure during CPR. Results Forty-seven students were recruited. Mean compression rates did not differ between the 3 groups. However, the mean percentage of adequate compressions in the CCO group was significantly lower than that of the 15:1 or 30:2 group ($31.2{\pm}30.3%$ vs. $55.1{\pm}37.5%$ vs. $54.0{\pm}36.9%$, respectively; P<0.001) and the difference occurred within the first minute. The RPE score in each minute and heart rate change in the CCO group was significantly higher than those of the C:V ratio groups. There was no significant difference in maximal oxygen uptake between the 3 groups. Energy expenditure in the CCO group was relatively lower than that of the 2 C:V ratio groups. Conclusion CPR using a 15:1 C:V ratio may provide a compression quality and exercise intensity comparable to those obtained using a 30:2 C:V ratio. An earlier decrease in compression quality and increase in RPE and heart rate could be produced by CCO CPR compared with 15:1 or 30:2 C:V ratios with relatively lower oxygen uptake and energy expenditure.