• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.193-197
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• 2017

In this paper, we present a low-power delta-sigma based digital frequency synthesizer with high frequency resolution for bio sensor networks. Biomedical radio-frequency (RF) transceivers require miniaturized forms with a long battery life and low power consumption. For the technology scaling, digital circuits have become preferable compared to analog circuits because of the aggressive cost, size, flexibility, and repeatability. Therefore, the digital circuits based on standard-cell library are used to reduce a power consumption. Additionally, a delta-sigma is used for making fractional frequency tuning range. From the simulation, we confirmed that proposed scheme has good performance in accordance with power and frequency resolution.

• Nutrition Research and Practice
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• v.6 no.1
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• pp.86-90
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• 2012

This study assessed the association between vitamin D sufficiency (serum 25(OH)D ${\geq}30ng/mL$) and alcohol consumption using data from the Korea National Health and Nutrition Examination Survey conducted in 2009. The following characteristics were obtained in 7,010 Korean participants ${\geq}19$-years-of-age: serum 25(OH)D level, alcohol consumption (drinking frequency, drinking number of alcoholic beverages on a typical occasion, average daily-alcohol intake), and potential confounders (age, residence, housing status, occupation, total fat and lean mass, smoking, physical activity, history of liver diseases, liver function, and daily intake of energy, protein, and calcium). After adjusting for confounders, vitamin D sufficiency in men was significantly associated with drinking frequency, number of alcoholic drinks consumed, and average daily alcohol intake; odds ratio of 1.21-1.72, 2.17-3.04, and 2.27-3.09, respectively. Increase in the three alcohol drinking-related behaviors was also linearly associated with increase in serum 25(OH)D level in men. By comparison, there was no significant association between alcohol intake and serum 25(OH)D level in women. The positive association between vitamin D sufficiency and alcohol consumption was evident only in Korean men.

• Journal of the Ergonomics Society of Korea
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• v.18 no.1
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• pp.1-12
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• 1999

The objective of this study was to investigate the metabolic energy consumption rate of the psychophysical Maximum Acceptable Weight of Loads (MAWLs) for different manual materials handling tasks. Lifting activities with four different lifting frequencies (2, 5, 8, 11 lifts/min) for a lifting range (from floor to 76cm height) were studied. The oxygen consumption rate and heart rate were measured or recorded while subjects were lifting their MAWLs. It was found that the relationship between MAWL and frequency can be described best by the exponential function with the R-sq value 0.9865 for this study. Psychophysical MAWL decreased from 22.38 to 7.48 kg, while the oxygen consumption rate with the MAWL increased from 717.8 to $1114.7m{\ell}-O_2/min$ as the frequency increased from 2 to 11 lifts/min. Heart rate also increased from 104.5 to 120.7 bpm. The ratio of oxygen consumption for the MAWL to the Physical Work Capacity (PWC) ranged from 28 to 43%. The MAWLs were greater than or equal to the Maximum Permissible Limits (MPLs) when the frequencies were higher than 8 lifts/min. It seems that the MAWLs by psychophysical approach when the frequencies were higher than 8 lifts/min tend to be overestimated from the viewpoint of the physiological criterion of the oxygen consumption rates. From these findings it is suggested that the NIOSH Guideline should not be directly applied to Korean without reasonable modifications.

• Journal of Nutrition and Health
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• v.40 no.6
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• pp.566-575
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• 2007

The purpose of this research was to understand how individuals reflect on the frequency and quantity of foods that they consume. Participants selected 5 males and 15 females aged 30 years or older were first interviewed on the frequency of their food consumption. Then based on this data, they were given a cognitive interview using the method of verbal proving. The individual cognitive interviews were recorded with consent while being conducted after complete approval by the Seoul National University Institution Review Board. The recorded material was evaluated using a thematic analysis after transcribing them into text. By analyzing stages of reflection, the major barriers to make the device difficult are revealed: 1) More difficulty in remembering events over the course of a full year due to diversification in the types of food that people consume 2) difficulty calculating the average for seasonal foods 3) difficulty estimating the amount of consumption from the photos presented 4) difficulty estimating amount of consumption from the quantity presented 5) difficulty processing foods that people think are healthy and foods are unhealthy simultaneously 6) difficulty having to consider foods where target food goes in as an ingredient; 7) difficulties arising from having to increase frequency when the amount consumed is higher than the quantity that is presented 8) difficulty having to combine the frequency and quantity of each food item when numerous foods are clustered into one category. These findings show that the less participants were involved in cooking, the more diverse their eating habits were, and the more they tried to adhere to rules of filling out the questionnaire, the more it was difficult for them to come up with an answer to the question being asked. It therefore seems necessary to construct a Food Frequency questionnaire that is attentive to these problems that arise from the recall stages.

• Journal of Families and Better Life
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• v.31 no.5
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• pp.173-184
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• 2013

The purpose of this study was to investigate adolescent consumers' consumption trends to identify their tendency for conspicuous consumption. To investigate adolescent consumers' consumption factors and conspicuous propensity for consumption, mass media, peers' effects & conformity were examined. The objects of the study are 503 middle and high school students in Seoul. The data were analyzed through frequency analysis, mean, standard deviation, t-test, Pearson's correlation, and hierarchical multiple regression analysis by using SPSS Win 12.0. The major results of this study are as follows: Firstly, the factors of gender, grade and allowance suggest a consumption-oriented attitude and conspicuous consumption is revealed to be the highest among female students rather than male students, and high school students rather than middle school ones. Allowance is significantly correlated with consumption-oriented attitude and conspicuous consumption. Secondly, factors that affect the propensity for the consumption-oriented attitude of adolescent consumers are mass media, peer conformity, and effects. Thirdly, the factors affecting the propensity for the conspicuous consumption of adolescent consumers are peers' effects, mass media, and peer conformity. This investigation could contribute to enhancing the understanding of adolescent consumers.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.73-81
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• 1999

Shake mixing has been widely used in cell culture. The mixing performance for shake mixing, however, has not been reported quantitatively. The critical circulating frequency and the power consumption for complete suspension of particles, based on the definition of Zwietering, were measured in a shaking vessel containing a solid-liquid system. The critical suspension frequency was correlated by the equation from Baldi's particle suspension model modified with the physical properties of the particles. Critical suspension frequency was correlated as following ; $$N_{JS}={\frac{0.58\;d{_p}^{0.06}(g{\Delta}{\rho}/{\rho}_L)^{0.004}X^{0.03}}{D^{0.35}d^{0.17}{\upsilon}^{0.04}}}$$ The power consumption at the critical suspension condition in the shaking vessel was less than that in an agitated vessel with impeller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.871-876
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• 2011

In this paper, a voltage-controlled frequency tunable current-mode integrator and a 3rd-order current-mode Chebyshev filter in 1.8V-$0.18{\mu}m$ CMOS is realized for software radio applications in system-on-chips. This filter is used for reconstruction purposes between a current-steering DAC and a current-mode mixer. Power consumption of the designed filter can be reduced by using a current-mode small size integrator. And also, cutoff frequency of this filter is variable between 1.2MHz and 10.1MHz, the power consumption is 2.85mW. And the voltage bias compensated circuit is used to control the voltage variation.in the designed filter.

• Nutrition Research and Practice
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• v.10 no.2
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• pp.198-205
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• 2016

BACKGROUND/OBJECTIVES: A healthy diet has been reported to be associated with physical development, cognition and academic performance, and personality during adolescence. This study was performed to investigate the relationships among milk consumption and academic performance, learning motivation and strategies, and personality among Korean adolescents. SUBJECTS/METHODS: The study was divided into two parts. The first part was a survey on the relationship between milk consumption and academic performance, in which intakes of milk and milk products and academic scores were examined in percentiles among 630 middle and high school students residing in small and medium-sized cities in 2009. The second part was a survey on the relationships between milk consumption and learning motivation and strategy as well as personality, in which milk consumption habits were collected and Learning Motivation and Strategy Test (L-MOST) for adolescents and Total Personality Inventory for Adolescents (TPI-A) were conducted in 262 high school students in 2011. RESULTS: In the 2009 survey, milk and milk product intakes of subjects were divided into a low intake group (LM: ${\leq}60.2g/day$), medium intake group (MM: 60.3-150.9 g/day), and high intake group (HM: ${\geq}151.0g/day$). Academic performance of each group was expressed as a percentile, and performance in Korean, social science, and mathematics was significantly higher in the HM group (P < 0.05). In the 2011 survey, the group with a higher frequency of everyday milk consumption showed significantly higher "learning strategy total," "testing technique," and "resources management technique" scores (P < 0.05) in all subjects. However, when subjects were divided by gender, milk intake frequency, learning strategy total, class participation technique, and testing technique showed significantly positive correlations (P < 0.05) in boys, whereas no correlation was observed in girls. Correlations between milk intake frequency and each item of the personality test were only detected in boys, and milk intake frequency showed positive correlations with "total agreeability", "organization", "responsibility", "conscientiousness", and "intellectual curiosity" (P < 0.05). CONCLUSION: Intakes of milk and milk products were correlated with academic performance (Korean, social science, and mathematics) in Korean adolescents. In male high school students, particularly, higher milk intake frequency was positively correlated with learning motivation and strategy as well as some items of the personality inventory.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.2
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• pp.252-260
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• 2014

This study discussed the consumption and purchase behaviors of wine by hotel F&B employees based on cluster analysis. Consumption behavior was separated into two categories: place and frequency of drinking. Purchase behavior was divided into two as well: place and price of purchasing. In general, consumption behavior was more influenced by drinking place rather than price, with a wine bar being the most preferred place to drink. Further, purchase behavior was more dependent on the price than place, specifically mid-range priced wine. When selecting wine, "taste" was the most important quality considered for both consumption and purchase behaviors, followed by "price". In addition, "vintage" and "country/winery" were also considered important for consumption behavior. There was no further significant difference among selection attributes for wine quality in terms of purchase behavior. Overall satisfaction after wine consumption was 3.73. Frequency of drinking had a greater impact on overall satisfaction than drinking place. Overall satisfaction after wine purchasing was 3.72, and satisfaction level was greater when a wine was purchased at a wine bar rather than a general bar. With respect to country of origin, France, USA, Chile and Argentina wines all showed even variation among selection attributes for wine quality. However, Italian wine displayed a below average score under "vintage" and "bottle design", whereas Spanish wine did so under "brand". Lastly, Australian wine displayed the lowest scores for all selection attributes.

• Journal of the Korean Home Economics Association
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• v.45 no.8
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• pp.105-126
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• 2007

The aims of this study were to examine the actual conditions surrounding the purchasing of online game items and Internet cyberspace items by adolescents the propensity of adolescents to consume these items, to determine the difference in the propensity for high and low consumption of these items among adolescents, and to investigate the characteristics of the adolescents who show a high propensity for the consumption of Internet items. The data for this study were collected from 483 adolescent consumers who were middle school and high school students in the city of Bucheon in Gyeonggi Province. The statistical methods used for the data analysis included frequency, percentage, standard deviation, t-test, and one-way ANOVA. The results of the present study can be summarized as follows. The majority(79.5%) of the students surveyed had had the experience of purchasing items. Most students(67.5%) had a rare frequency of buying ($1{\sim}2$ times in a period of 6 months or less). Nearly half (47.9%) of the students spent less than 1000 won per month on the item(s) purchased. Most of the students purchased items with their parents' permission, but 26.6% of the students bought the items without their parents' permission. Most of the characteristics of the items purchased, such as the major item purchased, payment method, amount purchased per month, average amount spent per buying experience, and whether or not they had their parents' permission differed according to gender, grade level, record, and monthly allowance. The level of propensity to consume the items was not high. The propensity of imitation consumption (1.96) was lower than that of impulsive consumption (2.38) and conspicuous consumption (2.45). Most of the buying characteristics, including the major item purchased, payment method, amount purchased per month, average amount spent per buying experience, parents' permission, grade level, and monthly allowance were different between the high and low propensity for consumption groups.