• Journal of the Korean Geotechnical Society
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• v.27 no.7
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• pp.47-57
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• 2011

The p-y curve has been used to design pile foundations subjected to lateral loading. Although the p-y curve has a large influence on the pile lateral behavior, p-y curves have not been clearly suggested. In this study, the p-y curve of clay was evaluated for drilled shafts in marine deposits by using 3-dimensional numerical analyses. First, the optimization study was performed to properly determine boundary extent, mesh size, and interface stiffness. The numerical modeling in the study was verified by comparing the calculated and the pile loading test results. Then, the p-y curves of single and group piles were evaluated from the parametric study. The selected parameters were pile diameter, pile Young's modulus and pile head fixed condition for a single pile, and pile spacing for group piles. Finally, the p-multiplier was evaluated by comparing the p-y curves of a single pile and group piles. As a result, the p-multiplier at pile spacing of 3D was 0.83, 0.67 and 0.78 for the front, middle, and back row piles, respectively, and showed values similar to those of O'Neill and Reese (1999). For the pile group with pile spacing larger than 60, the group effect can be ignorable.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.896-905
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• 2004

In this paper, the design, fabrication and experiment on a planar array antenna with a flat-topped radiation pattern for a mobile base station antenna were described. The current distribution of an antenna aperture, which is easily realizable in a feeding network compared with the conventional one of sin(x)/x was optimized for shaping a desired flat-topped radiation pattern. The planar array antenna designed in this paper has a rectangular lattice and is composed of array elements of 16${\times}$8. Each radiating element, which is a microstrip element fed coaxially, has a linear vertical polarization and the feed network which use a Wilkinson power divider and a 180$^{\circ}$ ring hybrid coupler as a base element is designed. The flat-topped radiation pattern with 90$^{\circ}$ is shaped by 16 array elements with the element spacing of 0.55 λ$_{ο}$ in the azimuth plane, and the normal radiation pattern with 10$^{\circ}$ is shaped by 8 array elements with the element spacing of 0.65 λ$_{ο}$ in the elevation plane. Also, the planar array antenna is symmetrically divided into four parts. It consists of one hundred-twenty-eight radiating elements, thirty-two 1-4 column dividers, low 1-8 row dividers and one 1-4 input power divider. In order to verify electrical performances of the planar way antenna proposed in this paper, the experimental breadboard operated in tile band of 1.92～2.17 GHz(IMT2000 band) was fabricated, and its experimental results were a good agreement with simulation ones.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.4
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• pp.106-117
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• 2021

In Korea, interest in truck platooning is increasing because most cargo transportation is done by road. Truck platooning is the operation of two or more trucks in a row to form one platoon, which can increase road capacity and improve fuel efficiency. In this study, to analyze the effect of truck platooning on traffic flow, scenarios were created according to traffic conditions and truck platooning operating conditions. In order to understand the effect of the truck platooning operating conditions, correlation analysis was conducted with the average travel speed, the number of lane change disturbance, and the number of disturbance in the entry/exit section. As a result, the number of trucks in the platoon, the spacing of trucks in the platoon, and the spacing between platoons were found to have an effect on the average speed and the number of lane change disturbance In addition, the truck platooning ratio was found to have a strong correlation with the average travel speed and the number of lane change disturbance regardless of the LOS.

• Korean Journal of Medicinal Crop Science
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• v.3 no.2
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• pp.140-145
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• 1995

This experiment was carried out to investigate the effect of plant spacing on the growth and root yield at different harvesting year in Astragalus membranceus. A local variety collected in Jung Sun. Kang Won was used on the 30 and 40cm row spacing, with different spacing between plant of 5, 10, 15, 20cm respectively. Nitrogen, phosphorus and potassium fertilizers were applied as 6, 8 and 9kg/10a respectively, with compost of 1,000kg/10a. Branches, root length, root diameter and root weight were increased in the sparse planting compared with the dense planting. But emergence date, flowering date, stem height and node number were not significantly changed with plant spacing. The highest root yield was 211.8kg/10a at the $30{\time}10cm(67\;plants/m^2)$ in 1 year old plants of Astragalus membranceus. In case of two years old plants, branches, node number, root length, root diameter and root weight were increased in the sparse planting compared to the dense planting. But harvesting ratio was decreased in the dense planting, The highest dried root yield was 292kg/10a at the $40{\time}10cm\;(25\;Plants/m^2)$. In case of 3 years old plants, aerial part and root growth pattern were similar to the 2 years old plants, The dried root yield was highest(623kg/10a) in the $40{\time}10cm(25plants/m^2)$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.39-43
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• 1995

In the culture of Vinyl mulching and Non mulching, growth, yield, and cotton hair's growth are studied at the different planting density to get a basic material for cotton culture and high yield bumper crop in the region of the South. And the results are following. Vinyl mulching is the best one at the strength, the number of boll bearing branches, the num-ber of bolls, the number of bolls per $m^2$ and all the other characters. Vinyl mulching and Non mulching have the greatest number of bolls per $m^2$ at the planting density of 70${\times}$10cm. Vinyl mulching has the highest seed cotton yield and the highest seed cotton yield per boll. Especially when planted at the density of 70${\times}$l0cm, Vinyl mulching and Non mulching have the highest seed cotton yield. Vinyl mulching's value is accepted in fiber length and lint percentage, the wider spacing in the row is, the longer fiber length is.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.22-27
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• 1992

This study was conducted to select an excellent goods and to estabilish the plant density of Amorphohpallus konjac. K about 3 local varieties and 2 introduced varieties through each fertilizer level. 1. Plant height and leaf width were increased according to increasing fertilizer level, and tuber yield was the highest at N-P$_2$ $O_{5}$ -K$_2$ O (14-10-14kg) per 10a as 390kg in Geumsan. 2. The more tuber size was large, the more yields per plant due to increasing the plant height and leaf width at low densities, while yields per 10a was decreased. 3. Among 5 varieties used, Jechon cultivar was good as a propagating variety because of increasing number of tuber and bulblet and Japan cultivar was high tuber yield per 10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.185-191
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• 1981

The purpose of this paper is to define and describe a series of growth stages for maize. cv. MTC-l (early) and Suweon No. 19 (late) that are easily identifiable by both professional agronomists and farmers. Plants were grown at a density of 60cm row with plant spacing of 15cm at six different seeding times in 1980. Leaf development indices with ten grades (LDI) were identified and defined in accordance with the development of a leaf blade. Leaf appearance rate (LAR) was ca. 3 days and it was not influenced by the variety or seeding time. The elongation of the first internode above the ground level began in a month after emergence and it corresponded to the 8th or 9th leaf stage. Internodes elongated in regular sequence of node position. The morphological change of silks related closely with the development of kernel. The duration of generative development was not influenced by varieties and seeding time but that of vegetative growth was influenced. A new scheme for the maize which was made by the developed leaves, visible nodes above ground level, morphological change of silks and development of kernel was proposed.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.89-94
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• 2016

This study was conducted to determine the optimum nutrient solution, pH, irrigation interval, light intensity and planting density to growth of common ice plant (Mesembryanthemum crystallinum L.) in a closed-type plant production system. Three-band radiation type fluorescent lamps with a 12-h photoperiod were used. Nutrient film technique systems with three layers were used for the plant growth system. Environmental conditions, such as air temperature, relative humidity and $CO_2$ concentration were controlled by an ON/OFF operation. Treatments were comparison of the nutrient solution of Horticultural Experiment Station in Japan (NHES) and the nutrient solution of Jeju National University (NJNU), pH 6.0 and 7.0, irrigation interval 5 min and 10 min, light intensity 90 and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and within-row spacing 10 cm, 15 cm, 20 cm and 25 cm with between-row spacing 15 cm. Optimum macronutrients were composed N 7.65, P 0.65, K 4.0, Ca 1.6 and Mg $1.0mM{\cdot}L^{-1}$. There were no significant interactions between pH 6.0 and 7.0 about shoot fresh weight and shoot dry weight of common ice plant. Irrigation interval 5 min and 10 min was also the same result. Shoot fresh weight and shoot dry weight were highest at $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Shoot fresh weight and shoot dry weight were decreased according to increasing the planting density. From the above results, we concluded that optimum nutrient solution, optimum levels of pH, irrigation interval, light intensity and planting density were 6.0-7.0 and 10 min, $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and $15{\times}15cm$, respectively for growth of common ice plant in a closed-type plant production system.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.106-110
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• 2016

In this study, a planting density-growth-harvest (PGH) chart was developed to easily read the growth and harvest factors such as crop growth rate, relative growth rate, shoot fresh weight, shoot dry weight, harvesting time, marketable rate, and marketable yield of common ice plant (Mesembryanthemum crystallinum L.). The plants were grown in a nutrient film technique (NFT) system in a closed-type plant factory using fluorescent lamps with three-band radiation under a light intensity of $140{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and a photoperiod of 12 h. Growth and yield were analyzed under four planting densities ($15{\times}10cm$, $15{\times}15cm$, $15{\times}20cm$, and $15{\times}25cm$). Shoot fresh and dry weights per plant increased at a higher planting density until reached an upper limit and yield per area was also same tendency. Crop growth rate, relative growth rate and lost time were described using quadratic equation. A linear relationship between shoot dry weight and fresh weights was observed. PGH chart was constructed based on the growth data and making equations. For instance, with within row spacing (= 20 cm) and fresh weight per plant at harvest (= 100 g), we can estimate all the growth and harvest factors of common ice plant. The planting density, crop growth rate, relative growth rate, lost time, shoot dry weight per plant, harvesting time, and yield were $33plants/m^2$, $20g{\cdot}m^{-2}{\cdot}d^{-1}$, $0.27g{\cdot}g^{-1}{\cdot}d^{-1}$, 22 days, 2.5 g/plant, 26 days after transplanting, and $3.2kg{\cdot}m^{-2}$, respectively. With this chart, we could easily obtain the growth factors such as planting density, crop growth rate, relative growth rate, lost time and the harvest factors such as shoot fresh and dry weights, harvesting time, marketable rate, and marketable yield with at least two parameters, for instance, planting distance and one of harvest factors of plant. PGH charts will be useful tools to estimate the growth and yield of crops and to practical design of a closed-type plant production system.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.252-252
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• 2017

Nowadays water shortage is becoming one of the biggest problems in the Korea. Many different methods are developed for conservation of water. Soil water management has become the most indispensable factor for augmenting the crop productivity especially on soybean (Glycine max L.) because of their high susceptibility to both water stress and water logging at various growth stages. The farmers have been using irrigation techniques through manual control which farmers irrigate lands at regular intervals. Automatic irrigation systems are convenient, especially for those who need to travel. If automatic irrigation systems are installed and programmed properly, they can even save you money and help in water conservation. Automatic irrigation systems can be programmed to provide automatic irrigation to the plants which helps in saving money and water and to discharge more precise amounts of water in a targeted area, which promotes water conservation. The objective of this study was to determine the possible effect of automatic irrigation systems based on soil moisture on soybean growth. This experiment was conducted on an upland field with sandy loam soils in Department of Southern Area Crop, NICS, RDA. The study had three different irrigation methods; sprinkle irrigation (SI), surface drip irrigation (SDI) and fountain irrigation (FI). SI was installed at spacing of $7{\times}7m$ and $1.8m^3/hr$ as square for per irrigation plot, a lateral pipe of SDI was laid down to 1.2 m row spacing with $2.3L\;h^{-1}$ discharge rate, the distance between laterals was 20 cm spacing between drippers and FI was laid down in 3m interval as square for per irrigation plot. Soybean (Daewon) cultivar was sown in the June $20^{th}$, 2016, planted in 2 rows of apart in 1.2 m wide rows and distance between hills was 20 cm. All agronomic practices were done as the recommended cultivation. This automatic irrigation system had valves to turn irrigation on/off easily by automated controller, solenoids and moisture sensor which were set the reference level as available soil moisture levels of 30% at 10cm depth. The efficiency of applied irrigation was obtained by dividing the total water stored in the effective root zone to the applied irrigation water. Results showed that seasonal applied irrigation water amounts were $60.4ton\;10a^{-1}$ (SI), $47.3ton\;10a^{-1}$ (SDI) and $92.6 ton\;10a^{-1}$ (FI), respectively. The most significant advantage of SDI system was that water was supplied near the root zone of plants drip by drip. This system saved a large quantity of water by 27.5% and 95.6% compared to SI, FI system. The average soybean yield was significantly affected by different irrigation methods. The soybean yield by different irrigation methods were $309.7kg\;10a^{-1}$ from SDI $282.2kg\;10a^{-1}$ from SI, $289.4kg\;10a^{-1}$ from FI, and $206.3kg\;10a^{-1}$ from control, respectively. SDI resulted in increase of soybean yield by 50.1%, 7.0% 9.8% compared to non-irrigation (control), FI and SI, respectively. Therefore, the automatic irrigation system supplied water only when the soil moisture in the soil went below the reference. Due to the direct transfer of water to the roots water conservation took place and also helped to maintain the moisture to soil ratio at the root zone constant. Thus the system is efficient and compatible to changing environment. The automatic irrigation system provides with several benefits and can operate with less manpower. In conclusion, improving automatic irrigation system can contribute greatly to reducing production costs of crops and making the industry more competitive and sustainable.