• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.257-262
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• 2007

The objective of this research was to develop a high yielding, early and medium-late flowering new hairy vetch(Vicia villosa Roth) varieties derived from an accession in Korea. Most vigorous early and medium-late flowering hairy vetch lines were selected and crossed by open pollination and their seeds were bulked and plants were reselected at Seongju in the Keongbuk and at Sacheon in the Keongnam. A performance trial was conducted to evaluate agronomic characteristics, forage quality and dry matter(DM) yield of new hairy vetch early-maturing 'Cold green' and medium-late maturing variety 'Cheong pa' at Seongju and Sacheon. 'Cold green' and 'Cheong pa' are hair but 'Haymaker plus' and 'Latigo' are nearly hairless. 'Cold green' has purple flowers while 'Cheong pa' has violet. The cold tolerance of 'Cold green,' 'Cheong pa' and 'Latigo' was higher than 'Haymaker plus' at Seong-ju, Keongbuk province, in inland region but there were a little differences at Sacheon, Keongnam province in southern coast region. Fifty percent-flowering dates of 'Cold green' and 'Haymaker plus' had earlier than others and 'Cheong pa' was earlier than 'Latigo'. The DM yield of 'Cold green' was higher than that of others, but 'Cheong pa' and 'Haymaker plus' had higher than 'Latigo' at Seong-ju(P<0.05). In Sacheon, The DM yield of 'Cold green' and 'Haymaker plus' was higher than others and 'Cheong pa' had higher than 'Latigo'.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.258-264
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• 2009

The principal objective of this study was to estimate the measurement uncertainty associated with determination of deoxynivalenol (DON), a mycotoxin generated by Fusarium strain, in food. In service of this goal, wheat as a food matrix was analyzed via high performance liquid chromatography-ultraviolet (HPLC-UV) detection using an immunoaffinity column for clean-up. The uncertainty sources in the measurement process were identified by sample weight, final volume, and sample concentration in extraction volume with components including standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. The expanded uncertainty for DON at a concentration of 300 ${\mu}g/kg$ was estimated as 71.62 ${\mu}g/kg$ using a coverage factor of two, which provides a confidence level of approximately 95%. The most influential component in the uncertainty sources was the recovery of the wheat matrix, followed by the calibration curve. These results indicate that all efforts may be directed toward reducing the uncertainties of the recovery of the wheat matrix and the calibration curve to obtain a reliable HPLC-UV method for DON analysis in wheat.

• Journal of Internet Computing and Services
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• v.5 no.1
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• pp.67-84
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• 2004

Real-time database systems (RTDBS) are database systems whose transactions are associated with timing constraints such as deadlines. Therefore transaction needs to be completed by a certain deadline. Besides meeting timing constraints, a RTDBS needs to observe data consistency constraints as well. That is to say, unlike a conventional database system, whose main objective is to provide fast average response time, RTDBS may be evaluated based on how often transactions miss their deadline, the average lateness or tardiness of late transactions, the cost incurred in transactions missing their deadlines. Therefore, in RTDBS, transactions should be scheduled according to their criticalness and tightness of their deadlines, even If this means sacrificing fairness and system throughput, And It always must guarantee preceding process of the transaction with the higher priority. In this paper, we propose an efficient real-time scheduling algorithm (Multi-level EFDF) that alleviates problems of the existing real-time scheduling algorithms, a real-time concurrency control algorithm(2PL-FT) for firm and soft real-time transactions. And we compare the proposed 2PL F[ with AVCC in terms of the restarting ratio and the deadline missing ratio of transactions. We show through experiments that our algorithms achieve good performance over the other existing methods proposed earlier.

• Fire Science and Engineering
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• v.26 no.3
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• pp.21-28
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• 2012

The objective of this study is to evaluate the prediction accuracy of FDS(Fire Dynamic Simulator) for the thermal and chemical characteristics of under-ventilated fire with unsteady fire growth in a semi-closed compartment. To this end, a standard doorway width of the full-scale ISO 9705 room was modified to 0.1 m and the flow rate of heptane fuel was increased linearly with time (until maximum 2.0 MW based on ideal heat release rate) using a spray nozzle located at the center of enclosure. To verify the capability of FDS, the predicted results were compared with a previous experimental data under the identical fire conditions. It was observed that with an appropriate grid system, the numerically predicted temperature and heat flux inside the compartment showed reasonable agreement with the experimental data. On the other hand, there were considerable limitations to predict accurately the unsteady behaviors of CO and $CO_2$ concentration under the condition of continuous fire growth. These results leaded to a discrepancy between the present evaluation of FDS and the previous evaluation conducted for steady-state under-ventilated fires. It was important to note that the prediction of transient CO production characteristics using FDS was approached carefully for the under-ventilated fire in a semi-closed compartment.

• Journal of Educational Research in Mathematics
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• v.16 no.3
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• pp.199-220
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• 2006

One of the main objectives of National Assessment of Educational Achievement (NAEA), which is implemented by Korea Institute of Curriculum and Evaluation(KICE), is to manage the qualities of National Curriculum. Thus we considered NAEA as the research for educational program assessment and tried to find out how to make NAEA better for achieving that objective. For the purpose of this paper we analyzed the present conditions of NAEA into four perspectives. And then according to each perspective we explored schemes for improving NAEA. In conclusion, we proposed the following; Firstly, in relation to assessing students' understanding of the mathematics contents, the meanings of Achievement Levels have to become much more clear and concrete. in relation to assessing for comparing student' understanding according to mathermatics content areas, the number of items has to be increased for elevating validities of NAEA. Thirdly, in relation to gathering the information about properties which are shown by the students in particular Achievement, it is necessary to think about how to produce items for the purpose in the step of developing items in NAEA. Finally in relation to collecting the data which can be useful for relevance of mathematics contents, it is necessary to make a special group of items for identifying relevance of mathematics contents, and to apply performance assessments on part of the students, not whole students.

• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.71-81
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• 2005

Objective : To elucidate the correlates of self-rated fatigue in Korean employees. Methods : The data for 10,176 (men, 7,984; women, 2,192; mean age, 34.2; SD: 8.8) employees recruited from a nationwide sample were examined. A structured questionnaire was used to measure the participants' fatigue, sociodemographics (sex, age, education, and marital status), job-related characteristics (work duration, grade at work, work hours, shiftwork, employment type, and magnitude of workplace), and health-related habits (smoking, drinking, coffee intake, and exercise). Two types of measurement for fatigue were used to evaluate the magnitude of fatigue: self-rated question and a standardized measurement tool (Multidimensional Fatigue Scale: MFS). Results : According to the self-rated fatigue, 32% of employees reported that they felt fatigue for the past two weeks, and 9.6% of males and 8.7% of females had experienced excessive fatigue (6 months or more). Hierarchical multiple regression analysis showed that fatigue measured by MFS was more common in women, younger, college or more graduated, single, and employees who do not regularly exercise. Fatigue was also associated with long work hours, and the size of the workplace (<1,000 employees). Conclusions : These results suggest that fatigue has been considered as a common complaint, and that it is affected by job-related factors like work hours and the workplace size as well as sociodemographics or health-related behaviors. Further research is needed to clarify the effects of fatigue on adverse health outcomes, work performance, work disability, sick absence and medical utilization, and to examine the relationship of job characteristics (e.g.: work demand, decision latitude) to fatigue.

• Journal of Preventive Medicine and Public Health
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• v.33 no.2
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• pp.150-156
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• 2000

Objective : To analyze the factors affecting the participation rate in the health screening program of medical insurance. Method : We investigated the factors associated with the participation rate in the health screening program in Korea. Data were collected at the aggregate level from 145 employee health insurance societies and 227 self-employed health insurance societies from 1995 to 1997 Data were also collected at the individual level from four health insurance societies. This study hypothesized that the participation rate of the health screening program was related to 1) the characteristics of its members and the size of the health insurance society; 2) the specifications of the health screening program; 3) the venue of the health screening institution and the interests of individuals in the health screening program; and 4) the activities of the health insurance society. We used bivariate and multiple regression models to examine the factors on the participation rate of the health screening program. Results : First, in the case of dependents of on employee health insurance society, the ratio of dependents 40 years old and over, the average monthly contribution per household, the interest and satisfaction level of individuals in health screening, and the level of refunds for over-payment were all associated with the participation rate in the health screening program, accounting for 54.4% of the participation rate. Second, in case of those insured by the self-employed health insurance society, the interest and satisfaction level of individuals in health screening, the level of refunds for over-payment, and the performance level of on-the-spot health screening were statistically significant, accounting for 40.1% of the participation rate. Conclusion : The factors concerning the participation rate in the health screening program of medical insurance, in both a health insurance society and for individuals, were closely related to the age and gender of individuals and household contributions.

• Tunnel and Underground Space
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• v.28 no.1
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• pp.38-58
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• 2018

The ventilation system plays a crucial role in underground mine safety. The main objective of the ventilation system is to supply sufficient air to dilute the contaminated air at working places and consequently provide tenable environment during the normal operation, while it also should be capable of controlling the fire propagation and facilitate rescue conditions in case of fire in mines. In this study, a smoke control fan was developed for the auxiliary ventilation as well as the fire smoke exhaust. It works as a free-standing auxiliary fan without tubing to dilute or exhaust the contaminated air from the working places. At the same time, it can be employed to extract the fire smoke. This paper aims to examine the smoke control efficiency of the fan when combined with the current ventilation system in mines. A series of the site experiments and numerical simulations were made to evaluate the fan performance in blind entry development sites. The tracer gas method with SF6 was applied to investigate the contaminant behavior at the study sites. The results of the site study at a large-opening limestone mine were compared with the CFD analysis results with respect to the airflow pattern and the gas concentration. This study shows that in blind development entry, the most polluted and risky place, the smoke fan can exhaust toxic gases or fire smoke effectively if it is properly combined with an additional common auxiliary fan. The venturi effect for smoke exhaust from the blind entry was also observed by the numerical analysis. The overall smoke control efficiency was found to be dependent on the fan location and operating method.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.21-30
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• 2016

Objective: This study aimed to examine the characteristics of joint kinematics and synchronicity of rowing motion between elite and non-elite rowers. Methods: Two elite and two non-elite rowers performed rowing strokes (3 trials, 20 strokes in each trial) at three different stroke rates (20, 30, 40 stroke/min) on two stationary rowing ergometers. The rowing motions of the rowers were captured using a 3-dimensional motion analysis system (8-infrared camera VICON system, Oxford, UK). The range of motion (RoM) of the knee, hip, and elbow joints on the sagittal plane, the lead time ($T_{Lead}$) and the drive time $T_{Drive}$) for each joint, and the elapsed time for the knee joint to maintain a fully extended position ($T_{Knee}$) during the stroke were analyzed and compared between elite and non-elite rowers. Synchronicity of the rowing motion within and between groups was examined using coefficients of variation (CV) of the $T_{Drive}$ for each joint. Results: Regardless of the stroke rate, the RoM of all joints were greater for the elite than for non-elite rowers, except for the RoMs of the knee joint at 30 stroke/min and the elbow joint at 40 stroke/min (p < .05). Although the $T_{Lead}$ at all stroke rates were the same between the groups, the $T_{Drive}$ for each joint was shorter for the elite than for the non-elite rowers. During the drive phase, elite rowers kept the fully extended knee joint angle longer than the non-elite rowers (p < .05). The CV values of the TDrive within each group were smaller for the elite compared with non-elite rowers, except for the CV values of the hip at all stroke/min and elbow at 40 stroke/min. Conclusion: The elite, compared with non-elite, rowers seem to be able to perform more powerful and efficient rowing strokes with large RoM and a short $T_{Drive}$ with the same $T_{Lead}$.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.55-61
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• 2003

The objective of this study was to investigate the characteristics of nitrate removal by conducting the column test in order to see the performance of surfactant modified zeolite (SMZ) as a permeable reactive barrier material. The prediction of nitrate removal was tested using the one-dimensional advective-dispersive model fitted to the experimental breakthrough curve. A methodology for scaling up to in-situ permeable reactive barrier was also proposed. The breakthrough of nitrate in the column packed with SMZ was well predicted using linear equilibrium adsorption model. The breakthrough time and half-life obtained by breakthrough experiment with variation of flowrates were decreased with the increase of flowrates. When 10㎥/day of groundwater containing the 50 mg/l of nitrate is to be treated to satisfy the potable water quality criteria (10 mg/l) by SMZ reactive barrier, 300 tons of SMZ and about 6 years of breakthrough time will be required, suggesting that 165 million wons are needed as barrier material expenses in each 6 years besides the initial design and construction expenses and the minimal monitoring and maintenance expenses.