• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.206-207
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• 2022

Currently, safety accidents in construction area are managed regardless of the size. Therefore, the objective of this study is to conduct for developing the quantitative risk assessment according to large and small and medium-sized construction sites. The scope of this study is limited to the fall accidents which is the biggest accidents in the construction sites. the regression analysis was conducted based on the collected data. As a result, it was confirmed that there was a statistically significant difference between larce and small and medium-sized construction sites. This study is expected to be used as basic data for research on the development of a risk quantitative model for small and medium-sized construction sites in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.4
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• pp.82-89
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• 2003

This study was carried out to find the suitable root-ball size for the planting construction of landscape trees. Surveyed trees for this study were Cercidiphyllum japonicum and Prunus yedoensis, and the root-ball size was classified into 3D, 4D, 5D, and 6D(D meaning the diameter at the base of a tree). Visual ratings on a scale of 1 to 9 were used as a means for measuring the regrowth strength after planting tested trees. Test trees with 3, 4, 5 and 6D root-ball size were planted on March. 16, 2002 and visual ratings were measured up to April. 30, 2003. Cercidiphyllum japonicum and Prunus yedoensis started showing a difference in regrowth by each rootball size a month after planting. The regrowth quality of Cercidiphyllum japonicum was low at 3D, medium at 4∼5D and high at 6D root-ball size, while the regrowth quality of Prunus yedoensis was low at 3∼4D and medium-high at 5∼6D root-ball size. According to the above results, a root-ball size for good regrowth quality was a little bit different between Cercidiphyllum japonicum and Prunus yedoensis. 4D of Cercidiphyllum japonicum and 5D of Prunus yedoensis could be guidelines for root-ball diameters at the base of trees when planting. However, we concluded that 4D∼5D root-ball is the optimum guideline for regrowth when adapting this guideline to all landscape trees with 8∼l0cm diameter at the base.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.171-174
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• 2015

Four pluriparous Korean black goat does were superovulated with FSH and mated with fertile bucks. Anesthetized animals were placed in lateral recumbency, then size 8 Foley catheter was inserted into the uterus through the cervix under the vaginal speculum and the balloon was inflated to fix the catheter in the uterine body. The opposite end of the catheter was connected to a 3-way and a flushing medium was infused into the uterus. Modified Dubecco's PBS with 1% FBS was used as the flushing medium. Four goats were allocated in two groups depending on the type of medium infusion into uterus. Injection group; the flushing medium was injected into uterus and the infused medium was collected by to-and-fro method using a syringe. Gravity-flow group; the flushing medium was allowed to enter the uterus by gravity flow by lifting the medium bottle and drained out of the uterus into a collecting tube. All four goats had catheter inserted through the cervix and uteri flushed successfully. The volume (recovery rate) of recovered medium varied considerably from 87 ml/200 ml (43.5%) to 148 ml/160 ml (92.5%). Nine embryos/ova in total were recovered from Gravity-flow group goats. Although the embryo recovery rate was low, the possibility of a transcervical embryo recovery in Korean black goat had been proven in this preliminary experiment.

• Smart Structures and Systems
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• v.26 no.6
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• pp.809-817
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• 2020

In cells, the microtubules are surrounded by viscoelastic medium. Microtubules, though very small in size, perform a vital role in transportation of protein and in maintaining the cell shape. During performing these functions waves propagate and this propagation of waves has been investigated using nonlocal elastic theory. But the effect of surrounding medium was not taken into account. To fill this gap, this study considers the viscoelastic medium along with nonlocal elastic theory. The analytical formulas of the velocity of waves, and the results reveal that the presence of medium reduces the velocity. The axisymmetric and nonaxisymmetric waves are separately discussed. Furthermore, the results are compared with the results gained from the studies of free microtubules. The presence of medium around microtubules results in the increase of the flexural rigidity causing a significant decrease in radial wave velocity as compared to axial and circumferential wave velocities. The effect of viscoelastic medium is more obvious on radial wave velocity, to a lesser extent on torsional wave velocity and least on longitudinal wave velocity.

• Human Ecology Research
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• v.52 no.2
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• pp.165-173
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• 2014

The study was conducted to analyze whether the recent trends in preference toward small and medium-sized housing in Korea represent changes in space norms. To accomplish this, the existing data from Statistics Korea and two different empirical data sets collected in 2007 and 2012 from Ulsan, Korea, were statistically analyzed through descriptive statistics, cross-tabulation analysis with a chi-squared test and multiple regression analysis. In the analyses, the space norms of households were compared and any changes in the space norms and the related factors were determined. The space norms were mainly investigated in terms of the housing size and the number of rooms. The results are as follows: 1) since 2010, there have been changes in the housing stock distribution in terms of size. Stocks of small housing increased, while those of medium and large housing decreased. Nevertheless, the overall conditions of spatial density have improved considerably in the recent 30 years. 2) It was found that there were statistically significant differences between 2007 and 2012 in space norms. The norms for housing sized less than 99 m2 and with one or two rooms were found to have increased, while that for housing sized more than 132 m2 decreased. 3) Household size, education of the head, monthly household income, housing type and the number of bedrooms in the current dwelling were the significant explanatory variables of space norms.

• Nutritional Sciences
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• v.9 no.3
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• pp.173-178
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• 2006

The purpose of this study was to investigate the effects of wax gourd on body weight, body fat, triglyceride, leptin and fat cell size in rats fed medium fat Male Sprague Dawley rats were fed with experimental diet containing total dietary fat at 20% of calorie with wax gourd (WG) for 4 weeks. Forty rats were divided into 4 groups including control, 5, 10, and 15% (w/w) WG supplement The results showed that weight gain was significantly higher in 5% WG than that in control (p<0.05), but was not different among the WG supplement groups. Total fat weight was significantly decreased in both 10 and 15% WG supplement groups than that of control. The levels of triglycerides and free fatty acids in the plasma were significantly decreased, particularly in 15% WG supplement group (p<0.05). The levels of leptin was not significantly different among the experimental groups. Fat cell size was significantly decreased in WG supplement groups compared to that of control group (p<0.05). Correlation among the parameters demonstrated that weight gain correlated positively with total fat weight, the levels of leptin and triglycerides. Taken these results together, 15% WG supplement diet substantially reduces total fat weight, triglycerides and free fatty acids levels and fat cell size in the rat fed midium fat.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.2
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• pp.44-50
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• 2007

This paper deals with the problem of scheduling jobs and rate-modifying activities on parallel machines. A rate-modifying activity is an activity that changes the production rate of equipment such as maintenance and readjustment. If a job is scheduled after the rate-modifying activity, then the processing time varies depending on the modifying rate of the activity. In this study, we extend the single machine problem to parallel machines problem and propose algorithms is to schedule the rate-modifying activities and jobs to minimize the makespan on parallel machines which is NP-hard. We propose a branch and bound algorithm with three lower bounds to solve medium size problems optimally. Also we develop three heuristics, Modified Longest Processing Time, Modified MULTIFIT and Modified COMBINE algorithms to solve large size problems. The test results show that branch and bound algorithm finds the optimal solution in a reasonable time for medium size problems (up to 15 jobs and 5 machines). For large size problem, Modified COMBINE and Modified MULTIFIT algorithms outperform Modified LPT algorithm in terms of solution quality.

• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.186-195
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• 2015

This study aims at modeling the rotary drying of wood chips in co-current mode and estimating the drying time of larch (Larix kaemferi) wood chip. Drying data were obtained in a lab. scale fixed bed dryer operating with an air velocity of 1 m/sec. and at hot air inlet temperatures of $100^{\circ}C$, $200^{\circ}C$, and $300^{\circ}C$. The lab. scale fixed-bed drying rates for small, medium and large size larch wood chips that had been dried from 40% wet-based moisture content (MC) to 10% MC at $200^{\circ}C$ drying temperature were 17.3 %/min., 10.2 %/min. and 5.5 %/min., respectively. It was predicted that larch large size wood chips could be dried from 40% MC to 10% MC in about 23.0, 34.6, and 44.7 minutes at $300^{\circ}C$, $200^{\circ}C$ and $150^{\circ}C$, respectively. Expected drying times for medium size chips were about 8.6, 11.2 and 13.2 minutes and those for small size chips were 4.3, 5.5 and 6.4 minutes, respectively.

• Korean Journal of Occupational Health Nursing
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• v.25 no.4
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• pp.277-289
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• 2016

Purpose: This study aims to investigate the cross-sectional association of company size and self-rated health using representative data on Korean workers. Methods: We used the data from 2,884 wage workers collected by Korean Labor and Income Panel Study (17th). The association between company size and self-rated health was analyzed using logistic regression with covariates including demographic characteristics, work environment, job satisfaction, and health-related behaviors. Resulst: Odds ratio (OR) for better health status among workers in large-sized company was 1.351 (CI. 1.054~1.731), compared to workers in small-sized company. We performed three separate models stratified by firm size (small, medium, and large companies). Occupation variables showed different effect on health depending on firm sizes. OR for better health of white-color job (referred to blue-color job) was 1.693 in medium-sized company model but it was 0.615 in large company model. OR for better health of the workers working shift work showed 0.606 in large company model but it was not significant in small and medium company models. Conclusion: We found that small-sized company workers have significantly poor self-rated health compared to large-sized firm workers. This study revealed that there exist differences among health related factors depending on firm sizes.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1009-1013
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• 1996

This study was carried to investigate the emulsion stability of microcrystalline chitins (MCC) prepared from chitins of different molecular sizes and different degrees of phosphorylation in a model fatty food system. Chitins of low, medium and high molecular size prepared from crabshells were phosphorylated to 30-50% to make MCC. MCC prepared from chitin of medium molecular size revealed a high emulsion stability. The best emulsion stability was observed in MCC prepared from medium size chitin with 40% phosphorylation (M-40-MCC). The fat binding capacity of MCC was not significantly different among the samples. MCC with 50% phosphorylation had more fat binding capacity, ranging from 650-690%. When 2.46% of M-40-MCC was applied to a coconutoil-water system as an emulsifier, emulsion separation was observed from 10 min after emulsification, indicating that it could not be used as a sole emulsifier. When 50% of emulsifier (Span-60 &Tween-60) in a liquid coffee creamer, selected as a model fatty foods, was replaced by M-40-MCC, emulsion stability was as good as control. Consistency of liquid creamer was decreased and L value increased as the amount of MCC repacement increased. A liquid creamer with 50% emulsifier replaced by MCC had sensory characteristics equivalent to control.