• ETRI Journal
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• 제28권4호
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• pp.537-540
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• 2006

When multiple ZigBee wireless personal area networks (WPANs) are in close proximity to each other, contentions and collisions in transmissions will lead to increased packet delays. However, there is no existing study on how delay performance would be affected in a crowded real-life environment where each person walking down a busy street would be wearing a ZigBee WPAN. This letter studies the use of ZigBee WPANs in such a real-life environment for real-time heart beat monitoring. To be pragmatic, we derived a mobility pattern from the analysis of a real-life video trace. Then, we estimated the delay performance from the video trace by combining data collected from ZigBee experiments. The results show that the 300 ms packet delay requirement will not be met for only 11% of the time. When failure occurs, it will last for an average duration of 1.4 s.

• 디지털산업정보학회논문지
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• 제9권2호
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• pp.1-10
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• 2013

In this paper, make a study decision problem called an optimal release policies after testing a software system in development phase and transfer it to the user. In the course of correcting or modifying the software, finite failure non-homogeneous Poisson process model, presented and was proposed release policies of the life distribution, half-logistic and log-logistic distributions model which used to an area of reliability because of various shape and scale parameter. In this paper, discuss optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement. In a numerical example, the parameter estimation using maximum likelihood estimation of failure time data make out, and software optimal release time was estimated.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권2호
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• pp.186-192
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• 2012

Half-rail stacked drivers are used to reduce power consumption of the drivers for synchronous buck converters. In this paper, the stacked driver is optimized by matching the average charging and discharging currents used by high-side and low-side drivers. By matching the two currents, the average intermediate bias voltage can remain constant without the aid of the voltage regulator as long as the voltage ripple stays within the window defined by the hysteresis of the regulator. Thus the optimized driver in this paper can minimize the power consumption in the regulator. The current matching requirement yields the value for the intermediate bias voltage, which deviates from the half-rail voltage. Furthermore the required capacitance is also reduced in this design due to decreased charging current, which results in significantly reduced die area. The detailed analysis and design of the stacked driver is verified through simulations done using 5V MOSFET parameters of a typical 0.35-${\mu}m$ CMOS process. The difference in power loss between the conventional half-rail driver and the proposed driver is less than 1%. But the conventional half-rail driver has excess charge stored in the capacitor, which will be dissipated in the regulator unless reused by an external circuit. Due to the reduction in the required capacitance, the estimated saving in chip area is approximately 18.5% compared to the half-rail driver.

• 한국산업보건학회지
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• 제3권1호
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• pp.91-98
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• 1993

This study was carried out to investigate characteristic of vinyl chloride emissioned from poly vinyl chloride extrusion process and to evaluate the efficiency of local exhaust ventilation system. Before local ventilation facility was constructed in poly vinyl chloride extrusion process, the average worker exposure to vinyl chloride was 3.15 ppm, which exceeded Threshold Limit Value of American Conference of Gorvernmental Industrial Hygienists (ACGIH-TLV), 1 ppm. lt is possible that vinyl chloride residues in the poly vinyl chloride resin was released or degased due to extrusion heat. The larger the width of vinyl tube become, the higher worker exposure to vinyl chloride was. It is estimated that vinyl chloride from vinyl chloride resin increased as amount of poly vinyl chloride resin extruded in the extrusion process increased. Canopy hood was an appropriate type for poly vinyl chloride resin extrusion process. This local exhaust ventilation has fan static pressure of 7.65 inch wg($190mmH_2O$, total volumetric flowlate of 4,796 CFM ($135.8m^3$/min) and fan power requirement of 12 hp (8.952 Kw). After this local exhaust ventilation was constructed there, the average concentration of worker exposure to vinyl chloride was reduced to be 0.46 ppm, which was below the Threshold Limit Value, 1 ppm. Also, the removal efficiency rate of vinyl chloride attained by local exhaust ventilation was 85.3%. It was a statistically significant (p<0.01).

• Nutrition Research and Practice
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• 제16권sup1호
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• pp.47-56
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• 2022

This paper examines the process and evidence used to create the Dietary Reference Intake (DRI) of alpha-linolenic acid (ALA) and eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) for Koreans. ALA (18:3n3) is an essential fatty acid, and EPA and DHA are known to have beneficial effects on cardiovascular disease risk and reduction of triglyceride levels. Various international organizations have suggested dietary recommendations for n-3 polyunsaturated fatty acids (PUFAs), including ALA, EPA, and DHA. A DRI for Koreans was established for the first time in 2020, specifically for the adequate intake (AI) of ALA and EPA + DHA. This recommendation was based on the average intake of ALA and EPA + DHA from the Korea National Health and Nutrition Examination Survey 2013-2017. For Korean infants, the AI of ALA and DHA was based on the fatty acid composition of maternal milk. Estimated average requirement and a tolerable upper intake level have not been set for n-3 PUFA due to insufficient evidence. In addition, the intake level of n-3 PUFA for prevention of chronic disease has also not been determined. Future studies and randomized controlled trials are required to establish the UL and to define the level for disease prevention.

• 동아시아식생활학회지
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• 제21권3호
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• pp.311-324
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• 2011

This study was performed to assess the nutritional status of low income elderly women aged ${\geq}$65 years residing in Gyeongnam Masan (n=124). Nutrition intakes, food intake frequency, and health-related behaviors including smoking, drinking, and exercise were investigated. Nutrition intake was calculated by the 24-hour recall method using CAN-pro (ver. 3.0). Average daily intakes of energy were $1,142.3{\pm}39$ kcal (71.4% of EER) in subjects aged 65~74 years and $1,071.0{\pm}41.7$ kcal (66.9% of EER) in subjects aged ${\geq}$75 years and the subjects consumed energy less than both 75% of estimated energy requirement (EER). The proportions of energy derived from protein, fat, and carbohydrate were 15.4:15.5:70.6 (aged 65~74 years), and 15.3:13.4:70.8 (aged ${\geq}$75). Nutrients consumed at less than estimated average requirements (EARs) were Ca (60.4%), P (98.4%), Zn (91%), vitamin E (48% of adequate intake, AI), vitamin $B_1$ (63.3%), vitamin $B_2$ (54%), niacin (87.7%), vitamin C (62.5%), and folate (50.5%). Especially, the intakes of Ca (58%), vitamin E (41% of AI), vitamin $B_1$ (60%), vitamin $B_2$ (50%), folate (46.5%), and vitamin C (54%) were 75% less than the EAR for people aged ${\geq}$75 years. According to the food intake frequency survey, the intakes of calcium, milk, fruits, and vegetables were very poor. In conclusion, this study suggests that a nutritional support program for elderly women of low socioeconomic class must be provided by the government to improve the quality of remaining life.

• Journal of Nutrition and Health
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• 제54권6호
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• pp.584-593
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• 2021

2020 한국인 영양소 섭취기준에서 탄수화물은 만성질환 예방을 위한 섭취기준으로 총 에너지 섭취량에 대한 탄수화물로부터의 에너지 섭취비율인 에너지적정비율을 1세 이후 모든 연령에서 55-65%로설정하였다. 그리고 2020년에 처음으로 탄수화물의 평균필요량과 권장섭취량을 설정하였다. 인체의 탄수화물 필요량은 뇌에서 하루에 소비되는 포도당량과 케톤체 생성이 나타나지 않는 양을 기준으로 1세 이후 모든 연령에서 1일 100 g을 설정하고, 권장섭취량은 15% 변이계수를 사용하여 두 배의 변이계수를 더한 130 g/일로 설정하였다. 탄수화물의 평균필요량은 최소필요량의 개념이지 에너지원으로서 적절한 섭취량에 대한 개념은 아니므로 탄수화물의 영양소섭취상태를 평가할 경우에는 평균필요량이나 권장섭취량에 비교하는 것은 적절하지 않고, 에너지적정비율을 활용하여 탄수화물로부터의 에너지 섭취비율의 적절성을 평가하는 것이 적절하다. 탄수화물은 에너지 적정비율범위에서 섭취할 때 만성질환의 위험을 낮출 수 있으며, 이를 탄수화물의 양뿐만 아니라 급원도 고려하는 식생활에 활용해야 할 것이다.

• Journal of Nutrition and Health
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• 제55권1호
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• pp.10-20
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• 2022

2020 한국인 영양소 섭취기준 개정에서 단백질은 기본적으로 질소평형을 유지하는데 필요한 단백질 양 0.66 g/kg 체중/일에 이용효율 90%를 적용한 평균필요량 0.73 g/kg 체중/일과 변이계수 12.5%를 적용한 권장섭취량 0.91 g/kg 체중/일을 생애주기별 체위기준치 변화에 따라 제시하였다. 그러나 성장기의 단백질 섭취기준에서는 체중 기준을 2017년에 개정된 소아청소년 성장도표에 근거하고, 일본 DRI 자료를 참고로 단백질 식품 이용효율을 차등 적용하였으며, WHO/FAO/UNU 보고서상의 성장에 필요한 단백질량 오류를 수정·반영하여 기준값을 개정하였다. 그 결과 일부 연령구간에서 섭취기준의 상향조정이 있었으나 한국인의 연령대별 1일 평균 단백질 섭취량은 대부분의 연령대에서 단백질 평균필요량의 100%를 넘는 것으로 나타났고, 남자 75세 이상과 여자 65세 이상을 제외하고는 권장섭취량과 비교했을 때도 많은 것으로 나타나 단백질 섭취기준의 상향 조정은 국민의 평균 단백질 섭취기준을 반영하는 것으로 판단된다. 한편, 75세 이상의 단백질 섭취량은 근감소증 예방, 근력 강화 등을 위해 65-74세 단백질 섭취기준과 동일하게 설정하였다. 이번 개정에서 단백질 에너지 적정비율은 기존의 7-20%를 유지하였으나 향후 단백질의 적정한 섭취수준 및 만성질환예방을 위한 단백질 필요량 설정에 관한 과학적 근거마련을 위해 우리나라 국민을 대상으로 한 다양한 중재연구가 수행되어야 할 것이다.

• Nutrition Research and Practice
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• 제4권3호
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• pp.229-234
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• 2010

Recently, we found and analyzed vitamin $B_{12}$ in some Korean traditional plant foods which had not reported, yet. This study was to investigate vitamin $B_{12}$ intake and its dietary sources and the vitamin $B_{12}$ status in the very old elderly Koreans. We measured serum vitamin $B_{12}$ level and estimated the amounts of vitamin $B_{12}$ intake from different dietary sources in female elderly Koreans aged 85 and over who had consumed a relatively low animal traditional diet for the whole life. The average age of the subjects (n = 127) was 98.0 years (85-108 years). The assessment on energy and nutrient intake involved a one-day 24-hour recall, and serum vitamin $B_{12}$ concentration was measured by radioimmunoassay. Overall diet pattern was not different between the 85-99 yr-old group and centenarians, except centenarians were taking more dairy product. The average ratio of plant food to animal food consumption was 87.5:12.5 in weight. The average vitamin $B_{12}$ intake of our subjects was 3.2 ${\mu}g$, and 52.7% of subjects consumed under estimated average requirement, 2.0 ${\mu}g$/day. On dietary source, 67.3% of dietary vitamin $B_{12}$ was from meat, eggs and fishes and 30.6% was from plant foods, such as soybean-fermented foods, seaweeds, and kimchi. The average serum vitamin $B_{12}$ concentration was 450.5 pg/mL, and low serum vitamin $B_{12}$ (< 200 pg/mL) was found in 9.6% of subjects. Dietary vitamin $B_{12}$ intake was significantly lower in subjects with low serum vitamin $B_{12}$ (0.79 ${\mu}g$/day) than those with normal serum vitamin $B_{12}$ (3.47 ${\mu}g$/day). There were no significant difference in vitamin $B_{12}$ intake and its dietary sources and serum vitamin $B_{12}$ level between the 85-99 yr- old group and centenarians. In conclusion, several plant-origin foods including seaweed, soybean-fermented foods, and kimchi, may contribute significantly to good vitamin $B_{12}$ status in very old elderly Koreans.

• Asian-Australasian Journal of Animal Sciences
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• 제17권1호
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• pp.39-45
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• 2004

Despite higher fecundity, Black Bengal goat generally has lower milk production, which is often insufficient for their multiple kids. However, milk requirement of Black Bengal kids is poorly defined. Present trial was thus designed to determine the requirement and intake of milk of pre-weaned Black Bengal kids in relation to their growth rate age and sex. Thirty, one month old Black Bengal kids of either sex divided into two groups were allocated to two groups, suckling alone (T1) or suckling along with teat-bottle feeding of milk (T2). Ten kids were allocated for the T1 and 20 kids were allocated for the T2. Digestibility of milk was also determined in T2 animals. Average daily consumption of milk, milk energy and milk N were 773 and 722 g, 1,170 and 1,093 kJ/kg $W^{0.75}/d$ and 1,552 and 1,462 mg N/kg $W^{0.75}/d$, respectively. During 9 weeks trial period, male kids had significantly higher live weight (4.32 vs. 4.20 kg; p<0.01) and intake of milk (773 vs. 722 g/d; p<0.05), energy (117 vs. 1,093 kJ/kg $W^{0.75}$/d; p<0.01) and N (1,552 vs.1,462 mg/k $W^{0.75}/d$; p<0.01) than the female. Milk consumption and the corresponding milk energy and milk N intake increased linearly up to 5th week of the trial, which, then decreased quadratically up to 9th week i.e., up to the weaning. Overall milk DM intake during this period was 2.58% (range 1.5-3.0%) of live weight or about 36 g/kg $W^{0.75}/d$ (range 29-45 g/kg $W^{0.75}/d$). Pre-weaned Black Bengal kids of about 4.5 kg weight, growing at the rate of 60 g weight daily requires at least 750 g milk daily. Daily live weight gain, estimated as the regression between the live weights over time, was 60 g ($r^2$=0.99) and 55 g ($r^2$=0.99), respectively, for the male and female kids. Efficiency of milk energy utilization for weight gain ranged from 0.67 to 0.84 (mean 0.81) for the male kid and 0.75 to 0.91 (mean 0.82) for the female kids. Efficiency of milk protein utilization for weight gain ranged from 0.46 to 0.70 (mean 0.61) for the male kid and 0.51 to 0.81 (mean 0.64) for the female kids. Additional teat-bottle feeding of suckling kids had no significant effect on their growth rate (54vs. 57 g/d). Average digestibility of milk DM, OM and N was 98.85, 98.99 and 98.69%, respectively and they were slightly (p>0.05) higher in the male than the female kids. Results suggest that the requirement of energy and protein and their utilization efficiency in Black Bengal kids is not different from that of the other breeds of goat.