• 대한지역사회영양학회지
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• 제8권6호
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• pp.993-1000
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• 2003

The purpose of this study was to provide baseline data for revising the recommended energy intake for Korean adults. We recruited 290 adults so as to determine their resting energy expenditure (REE) and energy intake. The REE was measured by indirect calorimetry. We also calculated the REE from prediction equations formulated by World Health Organization (WHO), The energy intake for two consecutive days was assessed using the 24 hour recall method. The body weight, lean body mass (LBM) and percentage body fat were measured using the INBODY 3.0 system. We compared the results of three age groups ; 20 to 29 years,30 to 49 years and 50 years or more. The average energy intake of each age group was below the 7th Korean Recommended Dietary Allowances (RDA). The average energy intake was lower in the older age groups. However, no difference was observed among the age groups when the energy intake as a percentage of the Korean RDA was compared. Our measurement of the REE was higher than the REE calculated by the WHO's method. Correlation coefficients between the measured and the calculated values of REE for all age groups showed significant correlations (r=0.475-0.672). As the ages of all the subjects increased, the REE/kg of body weight decreased. There were no significant differences in the REE / kg of the LBM between the different age groups; however, the REE/kg of the LBM was higher in the female group than in the male group. Negative correlations of the REE with the age (r=-0.242) and body fat ratio (r=-0.313) were observed; positive correlations of the REE with the BMI (r=0.265), height (r=0.570), weight (r=0.562) and LBM (r=0.586) were also found (p<0.01).

• 대한영양사협회학술지
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• 제7권2호
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• pp.153-158
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• 2001

This study examined the age-related patterns in body composition cross-sectionally using Segmental bioelectrical impedance analysis(SBIA), specifically its two components, lean body mass(LBM) and body fat mass, in 1,452 men and 1,436 women with an age range of 19 to over 70 years . Mean height of male subjects was 174.1cm at peak in early 20's and was decreased continuously 0.2-0.3 cm every year. Mean weight was greatest between late 20's and 40's, and was decreased quickly in 70's. Body fat mass was increased steadily before 30's and remained thereafter. Because decreasing lean body mass (LBM), percentage of body fat(PBF) increased continuously with aging. Mean height of female subjects was 161.7 cm at peak in 20's and was decreased steadily around 0.2 cm every year and thus an individual's height was decreased approximately 10 cm in their life cycle. Body weight was increased steadily until 50's and then was decreased. Body fat mass was increased continuously and LBM remained constant and thus PBF was increased steadily with aging. SBIA can be used to compare body composition between genders and between ages. In future studies, SBIA could be applied widely to evaluate variations of body composition in subjects with different nutritional problems.

• 인터넷정보학회논문지
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• 제5권2호
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• pp.75-84
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• 2004

지오캐스팅(geocasting)이란 멀티캐스팅의 특별한 한 종류로서, 어떤 특정한 지역(지오캐스트 영역이라 함)에 있는 모든 노드들에게 데이터를 전송하는 통신형태를 말하며, location-based multicasting(LBM) 이라고 부르기도 한다(1). Ad-hoc 네트워크는 중앙 집중화된 관리나 표준화된 지원 서비스 없이 배터리를 에너지원으로 사용하는 휴대용 기기들이 동적으로 연결되어 구성되는 임시적인 망이다. 따라서, 제한된 에너지 자원을 효율적으로 관리하는 것은 네트워크 활동시간(lifetime)을 최대화하기 위한 중요한 문제가 된다. 본 논문에서는 Ad-hoc 네트워크 환경에서 라우팅 설정시 에너지 값을 고려하여 중간 노드를 선택하는 LBPA(Location-Based Power Aware) 지오캐스팅 알고리즘을 제안한다. 전송 에너지를 균형있게 소비하여 각 이동 호스트의 잔여 에너지의 비율을 일정하게 유지시키는 방법으로 네트워크 활동시간 측면에서 볼 때 기존의 LBM 알고리즘보다 평균적으로 49%, 더 좋은 결과를 실험을 통하여 보여주었다.

• 핵의학기술
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• 제16권2호
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• pp.7-11
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• 2012

PET/CT에 사용되는 방사성의약품 FDG와 CT 조영제가 DXA를 이용하여 측정하는 BMC, BMD, TFM, LBM 등의 결과에 미치는 영향을 알아보고자 하였다. 2011년 12월부터 2012년 3월까지 본원 PET/CT를 시행한 환자 중 본 연구에 참여를 동의한 환자 총 22명을 대상으로 하였다. 실험은 두 집단으로 나누어 실험을 진행하였는데 첫 번째 집단은 17명으로 PET/CT 용 방사성의약품인 FDG 정맥 주사 전에 WB DXA를 시행한 다음 FDG 정맥주사 1시간 후 CT 조영제 사용 없이 PET/CT (Non-Contrast Enhancement $^{18}F$-FDG PET/CT)시행 후 즉시 다시 WB DXA를 진행하였다. 두 번째 집단은 총 5명으로 첫 번째 집단과 마찬가지로 FDG 정맥 주사 전 WB DXA를 시행한 다음 FDG 정맥 주사 1시간 후 CT 조영제 사용하여 PET/CT (Contrast Enhancement $^{18}F$-FDG PET/CT)시행 후 즉시 다시 WB DXA 진행하였다. 결과는 PET/CT 전 후 DXA에서 WB-BMC, WB-BMD, TFM 그리고 LBM 등을 측정하였고 각 항목의 변화율을 산출하여 비교하였다. Non-Contrast Enhancement $^{18}F$-FDG PET/CT 전 후의 골밀도 및 체성분의 변화율은 WB-BMC, +2.4%; WB-BMD, +1.8%; TFM, -6.8%; LBM, +2.2%였고 각 항목의 변화는 통계적으로 유의한 차이가 없었다. Contrast Enhancement $^{18}F$-FDG PET/CT 전 후의 변화율은 WB-BMC, +13.7%; WB-BMD, +9.3%; TFM, -34.1%; LBM, +13.6%였고 Contrast Enhancement $^{18}F$-FDG PET/CT 전과 후의 골밀도 및 체성분 측정치의 변화는 통계적으로 유의하였다. 본 연구에서 Non-Contrast Enhancement $^{18}F$ PET/CT 후에는 DXA 시행은 결과에 영향이 없어 가능할 것이라 생각되어지나 Contrast Enhancement $^{18}F$-FDG PET/CT검사 후에 시행한 DXA 검사의 결과는 신뢰도가 감소될 것으로 사료된다.

• 한국전산유체공학회지
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• 제11권3호
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• pp.28-36
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• 2006

NSBT(No Slip Boundary Treatment) is a newly developed scheme for the treatment of a no slip condition on the solid wall of obstacle in a flow field. In our research, NSBT was used to perform LBM simulation of a flow over a circular cylinder to determine the flow feature and aerodynamics characteristic of the cylinder. To ascertain the applicability of NSBT on the complex shape of the obstacle, it was first simulated for the case of the flow over a circular and square cylinder in a channel and the results were compared against the solution of Navier-Stokes equation. The simulations were performed in a moderate range of Reynolds number at each cylinder position to identify the flow feature and aerodynamic characteristics of circular cylinder in a channel. The drag coefficients of the cylinder were calculated from the simulation results. We have numerically confirmed that the critical reynolds number for vortex shedding is in the range of 200$\sim$250. For the gap parameter $\gamma$ = 2 cases at Re > 240, the vortex shedding were symmetric and it resembled the Karmann vortex. As the cylinder approached to one wall, the vorticity significantly reduced in length while the vorticity on the other side elongated and the vorticity combined with the wall boundary-layer vorticity. The resultant $C_d$ by LBM concurred with the results of DNS simulation performed by previous researchers.

• Journal of Nutrition and Health
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• 제29권9호
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• pp.1003-1012
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• 1996

We examined the relationship among riboflavin intake, work activity, erythrocyte glutathione reductase activity coefficient(EGR AC)and urinary riboflavin excretion. We also attempted to determine factors affecting seasonal riboflavin status of rural women. All information about nutrient intake, work activity and riboflavin biochemical status was repeatly collected in three seasons ; farming season(June), harvest season(October), nonfarming season(February). EGR AC was negatively correlated with riboflavin intake(P<0.005) and positively correlated with the duration(min) of farming activity(P<0.005) and the percentage of lean body mass(LBM) (%) representing long term physical activity(P<0.05) in harvestseason. Urinary riboflavin excretion was positively correlated with the ratio of riboflavin intake to 1,000kcal of energy expenditure (P<0.05) in farming season and negatively correlated with the duration(min) of farming activity (P<0.05) and crude nitrogen balance(P<0.005) in harvest season. It appeared that EGR AC seems to increase and urinary riboflavin excretion seems to decrease as work activity increase. Therefore work activity would be expected to deteriorate riboflavin status. Multiple regression analysis of variables showed that in general EGR AC was affected by riboflavin and energy intakes, energy expenditure, energy balance, the duration(min) of farming activity, LBM (%). Urinary riboflavin excretion was affected by riboflavin and protein intakes, LBM(kg) and crude nitrogen balance. Crude nitrogen balance affected urinary riboflavin excretion in all seasons. The result indicated that work activity as well as nutrient intake seemed to affect riboflavin status, especially EGR AC was affected preferentially be work activity in all seasons.

• 한국전산유체공학회지
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• 제22권1호
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• pp.103-109
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• 2017

The aerodynamic noise reduction of railway traction motor is required to satisfy new enhanced Korean noise regulations for a train. This paper is the study result on a noise reduction of a railway traction motor using Lattice Boltzmann Method(LBM). To verify the reliability of numerical analysis, the noise performance of the base model evaluated using LBM, and calculated result was compared with the experimental data. In addition, main noise sources were selected to design parameters through analyzing the flow field of the base model. Based on the noise sources analysis result, a design improvement model of traction motor for this study was derived to reduce the noise. The performance of a design improvement model was evaluated by applying a validated numerical scheme. As a result, it was confirmed that the noise was reduced due to the suppression of the internal turbulent flow components.

• Journal of Advanced Marine Engineering and Technology
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• 제38권10호
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• pp.1237-1243
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• 2014

The aim of the present paper is to analyze the friction and mass flow in a rough microchannel using Lattice Boltzmann Method (LBM). The LBM is a kinetic method based on the particle distribution function, so it can be fruitfully used to study the flow dependence on Knudsen number including slip velocity, pressure drop in rough microchannel. The surface roughness elements are taken to be considered as a series of circular shaped riblets throughout the channel with relative roughness height up to a maximum 10% of the channel height. The friction coefficients in terms of Poiseuille number (Pn), mass flow rate and the flow behaviors have been discussed in order to study the effect of surface roughness in the slip flow regime at Knudsen number (Kn), ranging from 0.01 to 0.10. It is seen that the friction factor and the flow behaviors in a rough microchannel strongly depend on the rarefaction effect and the relative roughness height. The friction factor in a rough microchannel is higher than that in smooth channel but the mass flow rate is lower than that of smooth channel. Moreover, it is seen that the friction factor increased with relative roughness height but decreased with increasing the Kundsen number (Kn) whereas the mass flow rate is decreased with increasing both of surface roughness height and Knudsen number.

• 한국소음진동공학회논문집
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• 제24권12호
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• pp.962-968
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• 2014

The lattice Boltzmann method(LBM) has attracted attention as an alternative numerical algorithm for solving fluid mechanics since the end of the 90's. In these days, its intrinsic unsteadiness and rapid increase in computing power make the LBM be more applicable for computing flow-induced noise as well as fluid dynamics. The lattice Boltzmann method is a weakly compressible scheme, so we can get information about both aerodynamics and aeroacoustics from single simulation. In this paper, numerical analysis on Aeolian tone noise generated by tandem-twin square cylinders in duct is performed using the LBM. For simplicity, laminar two-dimensional fluid models are used. To verify the validity and accuracy of the current numerical techniques, numerical results for the laminar duct and the cylinder flows are compared with the analytical solution and the measurement, respectively. Then, aerodynamic noise of the twin tandem square cylinders is investigated. It is shown that the aerodynamic noise from the twin tandem square cylinders can be reduced by controlling the distance between the cylinders.

• 국제초고층학회논문집
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• 제1권2호
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• pp.87-97
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• 2012

The indoor environments in high-rise buildings are generally well enclosed by defined boundary conditions. Here, a numerical simulation method based on the Lattice Boltzmann method (LBM), which aims to model and simulate the turbulent flow accurately in an enclosed environment, and its comparison with traditional computational fluid dynamics (CFD) results, are presented in this paper. CFD has become a powerful tool for predicting and evaluating enclosed airflows with the rapid advance in computer capacity and speed, and various types of CFD turbulence modeling and its application and validation have been reported. The LBM is a relatively new method; it involves solving of the discrete Boltzmann equation to simulate the fluid flow with a collision model instead of solving Navier-Stokes equations. In this study, the LBM-based scheme of flow pattern and particle dispersion analyses are validated using the benchmark test case of two- and three-dimensional and isothermal conditions (IEA/Annex 20 case); the prediction accuracy and advantages are also discussed by comparison with the results of CFD.