• Journal of Ecology and Environment
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• v.33 no.3
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• pp.253-260
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• 2010

It has been well established that leaf longevity is linked to the carbon economy of plants. We used this relationship to predict leaf lifetime carbon gains from leaf lifespan, and estimated the gross primary production (GPP) of a young deciduous forest of Japanese beech (Fagus crenata) located in central Japan. The light-saturated photosynthetic rates of the leaves were measured repeatedly during the growing season. We used the leaf lifespan to calculate the conversion coefficient from the light-saturated photosynthetic rate into the realized leaf lifetime carbon gain under field conditions. The leaf turnover rate was estimated using litter traps. GPP was estimated as the product of lifetime carbon gain per unit of leaf mass, and the annual leaf turnover rate. The GPP of the forest in 2007 was estimated to be $1.2{\times}10^3gCm^{-2}y^{-1}$, which was within the range of previously reported GPP values of beech forests in Japan, and was close to the GPP of a European beech forest, as estimated by eddy flux measurements.

• Journal of Korean Neurosurgical Society
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• v.46 no.5
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• pp.443-450
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• 2009

Objective : We estimated the number of Korean adults with back pain and evaluated population-based associated factors of back pain from a representative sample data from the Fourth Korea National Health and Nutrition Examination Survey. Methods : The number of Korean adults who experienced back pain (experienced patients), those who experienced back pain lasting for three or more months during the past year (chronic patients), and those who were currently suffering from back pain (current patients) were estimated by analyzing the data from the fourth Korea National Health and Nutrition Examination Survey conducted in 2007 using surveyfreq procedure of the SAS statistical package. Population-based odds ratios for being experienced, chronic, and current patient according to demographic (age and gender), socioeconomic (education and occupation), and lifestyle factors (smoking, drinking, and exercise) were estimated using surveylogistic procedure. Results : It was estimated that there were 5,554,256 (proportion, 15.4%; 95% CI, 4,809,466 - 6,299,046) experienced patients, 2,060,829 (5.7%; 1,557,413-2,564,246) chronic patients, and 3,084,188 (8.5%; 2,600,197 - 3,568,179) current patients among 36,107,225 Korean adults aged 20-89 years in 2007. Each of explanatory variables was significantly associated with at least one of the response variables for back pain. Conclusion : Based on our study results, further efforts to investigate epidemiology of back pain, to evaluate associated factors, and to improve treatment outcomes are needed.

• Environmental Analysis Health and Toxicology
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• v.16 no.3
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• pp.133-137
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• 2001

Acetanilide is a High Production Volume Chemical, which is produced about 2,300 tons/year in Korea as of 1998 survey. Most is used as an intermediate for synthesis of pharmaceuticals and dyes and the chemical is one of seven chemicals of which human and environmental risks are being assessed by National Institute of Environmental Research under the frame of OECD SIDS program. The chemical is water soluble (4 g/1 at 20$\^{C}$) and readily biodegradable (68.7％). Partition coefficiency (Log Pow) is 1.16 at 23$\^{C}$ so that the chemical has a low potential for bioaccumulation. The acute toxicities of algae, daphnia and fish are not high. The 72 hr-EｂC50 of algae is 13.5 mg/1,48 hr-EC50 of daphnia is over 100 mg/1 and 96 hr-LC50 of Oryzias latipes is over 100mg/1. Regarding the exposure, levels in air, water, soil or sediment have not been monitored or estimated so that risk evaluation of acetanilide was not possible. In this study, distribution of the chemical among environmental media was estimated using EQC model based on the chemical-physical properties. In Level I and IIof which the chemical are hypothesized in equilibrium and no transfer through the media, more than 98％ of acetanilide are estimated to be distributed in water. However, in Level Ⅲ of which non-equilibrium and intermedia transfer could be occurred, the chemical is estimated to distributed to soil as 51.8％ and water as 47.8％ as of total amount.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.801-806
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• 2013

Spiny lebbeid shrimp Lebbeus groenlandicus larvae were reared in the laboratory to estimate the energy budget from the zoeal to the post-larval stage. Energy expended by larvae on growth and respiration was determined from values for feeding, growth, molting, and metabolism. We calculated that 16.22 J were used for growth throughout all larval stages. Energy loss during molting was estimated as 1.03 J, and energy used for respiration was estimated as 1.31 J. Energy taken in by feeding was estimated as 77.16 J, while the sum of energies expended in excretion and egestion was 58.61 J. Larvae were estimated to assimilate 24.6% of ingested food as energy and to use ~85% of the assimilated energy for somatic growth. Gross growth efficiency ($K_1$) and net growth efficiency ($K_2$) were shown to be ~22% and 93%, respectively. Maintenance costs of respiration were estimated as ~9.7% of assimilated energy.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.10
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• pp.587-594
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• 2005

An adaptive observer for rotor resistance is designed to estimate rotor flux for the a-b model of an induction motor assuming that rotor speed and stator currents are measurable. A singularly perturbed model of the motor is used to design an Adaptive sliding mode observer which drives the estimated stator currents to their true values in the fast time scale. The adaptive observer on the sliding surface is based on the equivalent switching vector and both the estimated fluxes and the estimated rotor resistance converge to their true values. A speed controller considering the effects of parameter variations and external disturbance is proposed in this paper. First, induction motor dynamic model at nominal case is estimated. based on the estimated model, speed controller is designed to match the prescribed speed tracking specifications. Then a dead-time compensator and a robust controller are designed to reduce the effects of parameter variations and external disturbances. the desired speed tracking control performance can be preserved under wide operating range, and good speed load regulating performance. Some simulated results are provided to demonstrate the effectiveness of the Proposed controller.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.70-76
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• 2009

Web tension control system recently have been applied to OLED(Organic Light-Emitting Diode), RFID of flexible material, e-Paper and PLED(Polymeric LED) and various web control algorithms have being developed for higher productivity and product quality These system need an accuracy model to design and implement controller. In this paper, the web tension control system with dancer roll is mathematically modeled. Mathematical model consists of 8 subsystems and each subsystems can be described as impedance structure which connected by velocity and tension. Mathematical model is different from the estimated model at high frequency range because of structure dynamics which is ignored on mathematical model. The estimated model is derived using ARMAX model. The controller is designed using the estimated model. The step response of the estimated model are compared with that of physical model for a validation of estimated model. The experimental results show a good match between them.

• Journal of Soil and Groundwater Environment
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• v.15 no.2
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• pp.1-9
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• 2010

Estimations of porosity and bulk density, particle size analysis of soli samples, tracer test and slug test were performed in a petroleum contaminated area of Kangwon for understanding characteristics of the aquifer. Porosities of the samples were estimated 0.158~0.257, and bulk densities were estimated as $1.73\sim2.10\;g/cm^3$. Majority proportion of the soil samples was 0.5~1.0 mm size. In the soil texture triangle, all samples were distributed at sand area. Uniformity coefficients were estimated as 7.71~10.39, and thus all samples were poorly-sorted. In the tracer test, Darcy velocity was estimated to $4.8\times10^{-6}$ cm/day, effective porosity was 0.175, and longitudinal dispersivity was 0.1 m. According to the slug test, hydraulic conductivities of the test wells were estimated as $2.243\times10^{-2}\sim1.634\times10^{-2}$ cm/sec. These hydrogeologic parameters can be used for efficient remediation design of the petroleum contaminated area.

• Journal of Environmental Health Sciences
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• v.37 no.4
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• pp.258-266
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• 2011

Objectives: The aim of this study is to examine the possible changes over the past ten years in the estimated daily dietary lead intake (Pb-D) stemming from the variation of daily intake amounts for each food group. The following factors were considered; 1. time trends in Pb-D as the estimated values, 2. the time trend in Pb-D by food groups 3. the most influential food groups for dietary Pb intake. Methods: Estimated Pb-D was drawn from food consumption according to food groups reported in the Korean National Health and Nutrition Survey and the lead contents of each food group as reported in 23 prior publications. Results: The estimated Pb-D in a 2009 survey was 40.8 ${\mu}g/day$, of which 22.5 ${\mu}g/day$ (55.1%) was of plant origin and 18.3 ${\mu}g/day$ (44.9%) was of animal origin. Meats and poultry, fish and shellfish among foods of animal origin and beverages of plant origin had the largest contribution in Pb-D among the food groups. Conclusion: Over past ten years, daily lead intakes have slightly increased among men. Otherwise, no clear variation is apparent among women.

• Journal of Nutrition and Health
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• v.22 no.6
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• pp.423-437
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• 1989

A 4-week energy balance study was conducted to estimate the energy expenditure (EE) of 16 college age men and women, 20 to 26 year of age, by measurement of energy intakes and changes in body energy(BE) content(intake/balance technique), keeping their normal living pattern and maintenance body weight. Energy intake was measured by bomb calorimetry and estimated by food table. Fecal energy loss was calculated from nitrogen excreted. Fat mass was determined from body density estimated from skinfold tickness. 1) Gross energy (GE) intakes calculated from food table was not only 13.4% lower than those of bomb calorimetry but also lower 4 and 5% than metabolizable energy(ME) intakes for the male and female subjects, respectively. 2) Fecal energy loss was 7.2% and 6.9% proportion of the gross energy intake for the male and female subjects, respectively. 3) Mean daily metabolizable energy intakes estimated by subtract fecal and urinary energy loss was 2467kcal for the male subjects and 1897kcal for the female subjects. 4) Total body energy change estimated from body composition change over 31 days was decreased 7672kcal for the male subjects and 2689kcal for the female subjects. 5) Mean daily energy expenditure was 2714kcal (45kcal/kg of body weight) for the male subjects and 1984kcal(40kcal/kg of body weight) for the female subjects. 6) The estimated energy expenditure of college-age subjects in this study provide evidence to support the Recommended Dietary Allowances for energy of Korean normal adult.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.802-808
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• 2014

The purpose of this study is to suggest efficient methods for estimating population exposed to noises by analyzing differences of population exposed to noises estimated by each method through comparing exposed population estimated by utilizing existing methods and those estimated by using census output areas reflecting the actual population information of each address. For population exposed to noises, the error of exposed population estimated by using the per capita living space turned out to be the biggest, and other estimation methods had no significant difference. For population exposed to excess noises, as a result of analyzing population estimated by each method based on census output areas, the error of the method using a grid noise map turned out to be the biggest. For the method to estimate population exposed to noises by using a noise map, the estimation methods using census output areas and total ground area are considered to be more rational than the grid noise map estimation method or the method to estimate the living space per capita.