• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.264-273
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• 2016

This study was conducted to find out the influence of water stress from May to June on photosynthesis, shoot growth and fruit quality of apple trees. Fuji'/M.9 apple trees were root pruned at full bloom (30th April), parallel to the row of 30 cm or 60 cm from the trunk, to one side or both sides of trunk. The average value of afternoon leaf water potential from May to June of the no root pruning was maintained over -1.80 MPa, but that of root-pruning treatments was maintained under -1.80 MPa. In the comparison of average value of leaf water potential from May to June by root-pruning degree, the root pruning both sides at 30 cm from trunk was lowest (-2.06 MPa), followed by the root pruning both sides at 60 cm (-2.02 MPa) and the root pruning one side at 30 cm (-1.91 MPa). Root pruning one side at 30 cm or both sides at 60 cm reduced photosynthetic rate from May to June by 80% or 65%, respectively, compared with no root pruning. So, the degree of decreasing total shoot length or average fruit weight compare to the no root pruning of the root pruning one side at 30 cm was 25% or 11%, respectively, and those of the root pruning both sides at 30 cm was 45% or 15%, respectively. However, the soluble solid content and fruit color of the root pruning was higher than those of the no root pruning, and those of the root pruning both sides was higher than root pruning one side. These results indicate that the fruit enlargement was decreased when the average value of average leaf water potential from May to June was under -1.80 MPa, and the shoot growth was decreased when that was under -2.00 MPa.

• Journal of radiological science and technology
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• v.36 no.2
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• pp.111-122
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• 2013

This study was carried out to reduce patient dose through focus-detector distance, kilovoltage, and a combination of copper filters. In the C, L-spine lateral, Skull AP views were obtained by making changes of 60-100 kV in tube voltage and of 100-200 cm in focus-detector distance and by adding a copper filter when using an auto exposure control device in the digital radiography equipment. The incident dose showed 90 kV, 0.3 mmCu in C-spine lateral with 0.06 mGy under the condition of 200 cm; 100 kV, 0.3 mmCu with 0.40 mGy under the condition of 200 cm and 90 kV 0.3 mmCu in Skull AP with the lowest value of 0.24 mGy under the condition of 140 cm. It was observed that entrance surface dose decreased the most when was increased by 150 cm, 70 kV (C-spine lateral), 81 kV (L-spine lateral). It was also found out that as the between the focus-detector increased in the expansion of the video decreased but the difference was not significant when the distance was 180 cm or more. Skull AP showed the most reduction in the entrance surface dose when the tube voltage was changed by 80 kV, 0.1 mmCu, and 120 cm. Therefore, when using the automatic exposure control device, it is recommended to use the highest tube voltage if possible and to increase focus-detector distance at least by 150~200 cm in wall and 120~140 cm in table in consideration of the radiotechnologist's physical conditions, and to combine 0.1~0.3 mmCu and higher filters. It is thus expected to reduce patient dose by avoiding distortion of images and reducing the entrance surface dose.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.151-160
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• 2014

The purpose of this study was to investigate the GRF(ground reaction force) parameters according to the shoes's heel heights and ground landing distances during downward stairs on bus. Participants selected as subject were consisted of young and healthy women(n=9, mean age: $21.30{\pm}0.48$ yrs, mean height: $164.00{\pm}3.05cm$, mean body mass: $55.04{\pm}4.41kg$, mean BMI: $20.47{\pm}1.76kg/m^2$, mean foot length: $238.00{\pm}5.37mm$). They were divided into 2-types of shoe's heel heights(0 cm/bare foot, 9 cm) and also were divides into downward stairs with 3 types of landing distance(20 cm, 35 cm, 50 cm). A one force-plate was used to collect the GRF(AMTI, USA) data from the sampling rate of 1000 Hz. The GRF parameters analyzed were consisted of the medial-lateral GRF, anterior-posterior GRF, vertical GRF, loading rate, Center of Pressure(${\Delta}COPx$, ${\Delta}COPy$, COP area) and Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) during downward stairs on bus. Medial-lateral GRF and vertical GRF didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 9 cm shoes heel showed higher vertical GRF than that of 0 cm bare foot in landing distance of 50 cm. Also anterior-posterior GRF didn't show significant difference statistically according to the shoe's heel heights, but landing distance of 20 cm showed higher than that of landing distances of 35 cm and 50 cm in anterior-posterior GRF. Loading rate didn't show significant difference statistically according to the landing distance, but 9 cm shoe's heel showed higher than that of 0 cm bare foot during downward stairs. The ${\Delta}COPy$ and COP area didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 0 cm bare foot showed higher than that of 9 cm shoe's heel in ${\Delta}COPx$. Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) didn't show significant differences statistically according to the landing distance, but 9 cm shoe's heel showed decreased value than that of 0 cm bare foot in dynamics balance. Considering the above, parameters of GRF showed different characteristics according to the shoe's heel heights and ground landing distances during downward stairs on bus.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.99-104
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• 2013

Vegetables production in greenhouse are typically intensely managed with high inputs of fertilizers and irrigation water, which increases the risk of ground-water nitrate contamination. In 2010 and 2011, a study was conducted to determine the appropriate depth of soil moisture sensor for automatic irrigation control to use water and nitrogen efficiently under subsurface drip irrigation (SDI) systems. The irrigation line for SDI placed 30 cm below soil surface and tensiometer was used as soil moisture sensor. Three tensiometer treatments placed at 10 (SDI-T10), 20 (SDI-T20) and 30 cm (SDI-T30) depths below soil surface under SDI. These are also compared to SUR-T20 treatment where tensiometer placed at 20 cm below soil surface under surface drip irrigation (SUR) systems. The growth of cucumber was not statistically different between SUR and SDI without SDI-T30 treatment. Fruit yields (Mg/ha) were 57.0 and 56.9 (SDI-T10), 56.0 and 60.5 (SDI-T20), 40.9 and 41.2 (SDI-T30) and 56.6 and 54.3 (SUR-T20) for 2010 and 2011, respectively. Slightly higher total yield was observed in tensiometer placed 20 cm below the soil surface, although no significant differences were found between SDI-T10 and SDI-T20 under SDI treatments. In addition, nitrogen application rates and daily irrigation rates were lowest in SDI-T20 compared with other SDIs and SUR treatments. Nitrogen and daily irrigation application under SDI-T20 was lower than that under SUR-T20 by 6.0%. These findings suggested tensiometer 20 cm depth under SDI systems was best for cucumber production in greenhouse.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.28-32
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• 1988

The effects of standing water and cultivation frequency on emergence of Echinochloa glabrescens Munro ex. Hook were determined at varied seeding methods under simulated field conditions for 4 months. In soil-incorporated seeding method total emergence for 4 months was highest in saturated condition followed by 4, 2, and 8cm standing water, whereas total emergence of seeds sown at the soil surface was highest at 2cm standing water followed by 4cm, saturated soil, and 8cm standing water. Within 2 weeks the emergence was highest at 4cm and lowest at 2cm standing water with the soil-incorporated seeding, but the seeds sown at the soil surface with 2cm standing water resulted in the highest emergence. Ratio of emergence within 2 weeks over total emergence during 4 months was lowest at 2cm standing water in the soil incorporation, indication that 2cm standing water would be the critical water level for E. glabrescens. Since most of the seedling was emerged within 2 weeks just before cultivation, the emergence pattern was little affected by cultivation at each standing water level.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.365-374
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• 1999

To obtain informations on vertical movements of water and solute in rice paddy field during the growing season, soil water contents and bulk electrical conductivities (${\sigma}_a$) were monitored using Time Domain Reflectometry. Soil water contents with depth showed ${\varepsilon}$-shaped profiles constituting of partly saturated zones at top and bottom layers and unsaturated zones (20-100cm) between them. Analysis by fitting with a van Genuchten-type model showed that soil water contents at 60cm were affected by both water supplied from surface water and groundwater, but at 80cm mainly affected by groundwater. Water percolation at the rate of 2cm $day^{-1}$ rates were, but large fluctuation from 10 to 38cm $day^{-1}$ in C1 layer (60-90cm). Therefore, it can be said that any water or solute entering C1 layer is very rapidly transported to C2 layer, especially during the period of high groundwater table staying, and retarded to a relatively constant percolation rate in C2 layer. This can be manifested by the fact that rapid decrease and steady increase of electrical conductivities at 50 and 110cm depth respectively, were found around that period.

• Korean Journal of Construction Engineering and Management
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• v.22 no.6
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• pp.44-54
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• 2021

As the CM at Risk market grows recently, designers and CM companies that have been performing agency CM services have been showing their interests to participate in the CM at Risk projects. With the assumption that agency CM companies with a lot of experiences and know-how in the field of construction project management have created the circumstances to enter the CM at Risk market, this study investigates the competencies necessary for the agency CM companies to carry out the CM at Risk projects. The compentencies to run the CM at Risk projects were identified based on the literature review. A survey was conducted to identify the competencies that need to be supplemented first. The survey results revealed that competency related to partner companies, finance and guarantee, risk and claim, and project cost were identified to have a higher level of complementation compared to other competencies. In addition, considering that the level of competency that need to be secured is high, as the level of holding of all competency is on average 76% of the required level, in the beginning, small-scale CM at Risk projects with relatively low risk are mainly carry out, strengthening competency and then increasing the scale is considered more appropriate strategy.

• Korean Journal of Construction Engineering and Management
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• v.20 no.3
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• pp.22-30
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• 2019

The purpose of this study is to derive basic data of the Guaranteed Maximum Price(GMP) process and to present specimens that can be used at the time of execution of CM at Risk project in South Korea. CM at Risk project is issued in South Korea, but the actual data is lack. On the other hand, CM at Risk project is universalized and the market of the CM at Risk is steadily growing. Because of that, in this study, The United States cases was selected as a sample. GMP consists of CM's fee, CM contingency, project direct cost, project indirect cost, allowance. GMP negotiations are performed before the end of design completion, and after 3 rounds of estimation comparison, preliminary GMP is confirmed. GMP can be multiple contract and it is useful for Procurement of long lead materials and early construction. If the actual cost is lower than expected GMP, sharing of the saving is an option since the conflict of interests between the client and the contractor can occur.

• FLOWER RESEARCH JOURNAL
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• v.26 no.4
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• pp.195-201
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• 2018

The plant morphological and chromosome characteristics of 'Bonanza', 'Coral Candy' and 'Purple Crystal', a formolongi-Asiatic (FA) interspecific hybrid species bred at the National Institute of Horticultural Science, Rural Development Administration (RDA), were investigated in this study. The flowering time of these species were found to have some variation. 'Bonanza' flowers in the middle to late June (medium-late maturing cultivar), 'Coral Candy' in the mid of June (medium maturing cultivar), and 'Purple Crystal' was observed to be in early June (early maturing cultivar). The flowering direction of all three cultivars are upward facing flowers and having a weak fragrance. The height of the plants was recorded in the range between 101.0 cm ('Purple Crystal') to 142.3 cm ('Bonanza'), thus they are able to develop cut flowers with excellent stem elongation. Flower diameters of 'Bonanza' (17.1 cm) and 'Coral Candy' (16.9 cm) were classified to be large sized flowers. On the other hand, 'Purple Crystal' had a narrow flower diameter (12.3 cm) with an outer petal width of more than 4.0 cm. Leaf length was observed for 'Bonanza' (15.7 cm), 'Coral Candy' (19.7 cm), and 'Purple Crystal' (11.1 cm). Chromosome analysis was done using FISH technique. Results revealed that all three cultivars were observed as triploids (2n=3x=36). FISH analysis also showed 5S/45S rDNA of 'Bonanza', 'Coral Candy' and 'Purple Crystal' as 4/11 loci, 4/12 loci, and 4/11 loci, respectively. The results of the FISH analysis are useful as markers to distinguish cultivars, since the patterns of rDNA observed on the remaining chromosomes are significantly different except FISH patterns of chromosome #3.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.223-229
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• 2022

In this paper, the ignition trans used in boilers was studied. Regardless of the change in the ignition rod length and the ignition rod gap, the output frequency was measured between 59.5 and 61.3 Hz, and it was found that the low frequency circuit operated normally. When the ignition rod gap changed by 2 to 10 mm, the ignition rod length was measured from 2.8A to 3.45A at 30cm. The ignition rod length was measured from 9.37 A to 14.5 A at 500 cm and from 13.2 A to 32.6 A at 1000 cm. As the ignition rod length and the ignition rod gap increased, the current increased. As a result of measuring the secondary coil output voltage. The ignition rod length was measured from AC 0.84 kV to AC 1.75 kV at 30 cm, AC 1.17 kV to AC 1.944 at 500 cm, and AC 1.4 kV to AC 7.18 kV at 1000 cm. As the ignition rod length and the ignition rod gap increased, the output voltage of the secondary coil also increased. As a result of measuring the output voltage of the ignition trans, the ignition rod length was measured from DC 1.11 kV to DC 1.57 kV at 30cm, DC 2.49 kV to DC 3.72 kV at 500cm, and DC 3.78 kV to DC 9.42 kV at 1000cm, and the power voltage increased as the ignition rod length and interval increased.