• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.766-771
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• 2006

Railway stations are important facilities for transport of passengers and freights. The location of station have an effect on the efficiency of railway transport and operation. In this study, an inspection of the primary factors for station spacing in urban railway has been performed and a review for the propriety of the present states and further improvement has been carried. It may be helpful for proper decisions on the route planning in urban railway. Primary factors for station spacing are 1)train capacity, 2)competitiveness with other transportation, 3)accessibility and 4)construction cost, which is out of consideration in the inspection. From the result of this study, the proper station spacing is about 600m for the accessibility, more over 1.03km for the train capacity and more over 1.4km for the competitiveness with other transportation.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.67-71
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• 1997

Bupleurum falcatum is one of the oldest medicinal crop spontaneously generated as well as cultivated by man and successfully grown during the summer season in Korea. This study was conducted to examine the effect of planting density in the row spacing and hill spacing system using machine seeder on major agronomic traits, yield and labor saving. In 1993 and 1994, a spilt plot design was used with row spacing as the main plot and hill spacing as subplot. Labor saving efficency of the machine seeder reduced 96% than the hand seeding in sowing time required. Number of seeding stand increased, but stem height and number of nodes did not affect with different density in each row and hill spacing. There were reduced with narrow hill spacing on stem diameter, number of branches, shoot weight and root traits. There was no significant interaction between row and hill spacing for any major traits studied except shoot weight. Yield was more increase at 20cm than at 30cm row spacing. For these studies the optiomum density appears to be between drilling or 5cm hill spacing with 20cm row spacing. A highly significant positive correlation was appeared between number of seedling stand and root yield.

• Proceedings of the Korean Society of Crop Science Conference
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• 1989.02a
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• pp.54-55
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• 1989

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.605-608
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• 1993

Breakdown characteristics of a small rod-to-rod microairgap has been studied for obtain an optimum breakdown voltage and an airgap spacing to be used as an emission control means by the electrical arc-burning unburnt carbon particulates exhausted from a power station burner. It is found that the breakdown voltage at the rod-to-rod airgap spacing in the rang of $1{\sim}100{\mu}m$ decreased with decrease in the rod-to-rod airgap spacing. And there were no minimum breakdown voltage on a $V_b$-Pd characteristics which is known as the minimum voltage in Paschen's law in air atmosphere. Breakdown voltages of the airgap at the constant airgap spacing were $V_{b-dc}>V_{b-ac}>V_{b-pulse}$, and it was lowest for the pulse voltage applied. As a result, it is found that a pulse power was one of effective power compared with dc or ac to be used as such an unburnt carbon particulate emission control means and the airgap spacing became to several tens ${\mu}m$, then the breakdown voltages were down to several handreds voltages.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.133-137
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• 1969

This experiment was conducted to determine the optimum row width and plant spacing within row under the tropical environment for a leading soybean variety Palmetto and it was carried out at Eakmat Experiment Station in Vietnam. The experiments were arranged in a split plot design with four replications and the test was repeated twice in two years. Variations for seed yield due to the distance between rows were significant at 1 per cent level in 1967 test(dry season growing) and at 5 per cent level in 1968 test. Significant differences for plant height, lodging, maturity, number of branches per plant, and number of pods per plant due to the row width were not found in both tests, while significant differences in difference spacing within row was found in all traits studied. Interaction between width of row and spacing within row for seed yield and plant height were found at five percent level in 1967 test. These results indicate that close planting may increase in seed yield and plant height in both seasons, and decrease in loadging. From these studies, one could be understood that the plant population, particularly in dry season, plays decisive roles on seed yield in soybean culture, and the maximum plant height and minimum value of lodging index were also observed in closest spacing plots. The highest soybean yield in late planting would be expected by a combinations of 30 cm(between rows)${\times}$5cm(between hills) plot, while 40cm ${\times}$ 5cm planting method would be suggested for rainy season growing. Highest seed yield was obtained at closet spacing in both dry and rainy season, and these results led to drilling method in seeding where about 20 seeds per meter of row could be recommended. Besides the seed yield, the close planting may produce some advantages, such as increase plant height and decrease lodging, weeds and erosion of surface soil.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4759-4780
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• 2017

Full Dimension multiple input multiple output (FD-MIMO) architecture employs a planar array design at the Base Station (BS) to provide high order multi-user MIMO (MU-MIMO) via simultaneous data transmission to large number of users. With FD-MIMO, the BS can also adjust the beam direction in both elevation and azimuth direction to concentrate the energy on the user of interests while minimizing the interference leakage to co-scheduled users in the same cell or users in the neighboring cells. In a typical highly populated macrocell environment, modelling the elevation angular characteristics of three-dimensional (3D) channel is critical to understanding the performance limits of the FD-MIMO system. In this paper, we study the throughput performance of FD-MIMO system with varying elevation angular spread and inter-element spacing using a 3D spatial channel model. Our results show that for a typical urban scenario, horizontal beamforming with correlated antenna spacing achieves optimal performance but by restricting the spread of elevation angles of departure, elevation beamforming achieves high array gain with wide inter-element spacing. We also realize significant gains due to spatial array processing via modelling the elevation domain and varying the inter-element spacing for both the transmitter and receiver.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1374-1379
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• 2012

Urban rail transit tends to global grounding system in order to control ground potential rise and potential differences between electric equipments. In addition, global grounding system can discharge the large capacity surge current to the ground safely. Since some railway electric equipments are installed all section of line, the global grounding system connected with the connecting grounding wire is more effectively. However, if the fault occurred in the connecting grounding wire area, some dangerous voltage is generated. So, the installation of additional grounding rod will be required. In this study, the global grounding system is simulated using CDEGS program to analyze the divergence spacing of additional ground rod depending on dangerous electric potential characteristics. Grounding net of the each station is modelled in depending on the size of the platform, and the spacing of the connecting grounding rod are compared 50m, 100m, 250m and 400m. Simulation results considering of earth resistivity and underground condition of the connecting grounding wire, spacing of the connecting grounding rod is that less than 250m to spacing of the ground rod was appropriately confirmed.

• Proceedings of the Korean Society of Crop Science Conference
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• 1989.05a
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• pp.32-33
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• 1989

• Proceedings of the KOR-KST Conference
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• 1996.06a
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• pp.95-128
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• 1996

Dipped track profiles between rail transit stations can significantly reduce propulsive energy, braking energy and travel times. This work quantifies their potential benefits for circumstances reflected in various values for dips, speed and acceleration limits, station spacings, and available power. A deterministic simulation model has been developed to precisely estimate train motions and performance using basic equations for kinematics, resistance, power and braking. For a dip of 1% of station spacing, in which gradients never exceed 4%, our results show savings (compared with level tracks) exceeding 9% for propulsive energy, 15% for braking energy and 5% for travel time between stations.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.193-197
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• 2006

The optimum planting date, plant spacing, and harvest time for production of small-sized sweetpotato was evaluated in 2003 to 2004 at the Mokpo Experiment Station. Small-sized sweetpotato is important as snack food in Korea. Optimum planting date and plant spacing were with plastic mulch, and mid-April and $75{\times}15{\sim}20cm$ respectively, mid-June and $75{\times}15cm$ respectively without plastic mulch. Storage root yield decreased with early harvest, but the ratio of small-sized sweetpotato was higher in plots harvested after 100 days of planting (DAP) than that of 80 or 120 DAP. Considerable differences in storage root yield was noted with planting dates and plant spacings, but the use of plastic mulch resulted to smaller yield variations in plots, harvested in mid-April. Planting in mid-April and harvesting after 100 DAP increased income by about $32{\sim}61%$ compared with plantings mid-May.