• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2006.05a
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• pp.63-69
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• 2006

• Korean Journal of Plant Resources
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• v.20 no.4
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• pp.304-308
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• 2007

In order to find out the optimum fertilizer level and planting density of high yielding variety, $Okayma^{#2}$, this experiment was conducted with 3 compositions of fertilizer levels and a different plant density at the experiment paddy field of mat rush in Mokpo Experiment Station, National Institute of Crop Science, RDA. $Okayma^{#2}$, mat rush variety was grown under different fertilizer level and planting density with the highest yielding. Yield components such as stem length, number of stem were highest at the plots with fertilizer level (kg/10a), 80-20-40 and planting density, 20 ${\times}$ 10cm. Judging from the results reported above, at optimum fertilizer level and planting density of mat rush seemed to be 80-20-40kg/10a fertilizer and 20cm row spacing and l0cm or I5cm planting spacing.

• Journal of Sericultural and Entomological Science
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• v.36 no.2
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• pp.102-109
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• 1994

Profitability was analysed in the fields of various planting densities from 1,666 trees/10a to 4,166 with mulberry grafts or conventional saplings under the consideration of leaf yield and quality. Leaf yield per tree decreased with the higher planting densities. Seasonal and total leaf yield per area, however, increased by 20 to 63% as a mean for 3 years in the densities of 2,083~4,166 trees per 10a than in the conventional density of 1,666 trees per 10a. The increase in leaf yield per area was not so high in the densities over 2,083. Leaf yield in the sapling plots was a little higher than that in the graft plots. Topping of shoot tip affected neither on the branch length nor on yield. Yield was higher in the planting spacing with single raws than in that with double raws. Quality of leaves in the densities from 2,083 to 3,333 trees per 10a was relatively good judged based on the results of the pupation rate and cocoon yield and quality.

• Korean Journal of Medicinal Crop Science
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• v.5 no.2
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• pp.95-101
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• 1997

This study was conducted to investigate how a labor saving for conventional hand sowing and respond to major agronomic traits under different planting density in 1993 and 1994. Each trial was a randomized block split plot with row spacing as the main plots and hill spacing as subplots. Sowing rate appeared lower in 20 or 25cm hill spacing using machine seeder than in hand sowing. Sowing time required reduced more 121 hours per hectare in 60cm row, 20cm hill spacings using machine seeder than in hand sowing. Increasing row and hill spacings reduced number of seedling stand per unit $area(m^2)$. Both number of pods per plant and grain weight per plant and showed highly increase in wide planting. Best yield obtained in 60cm row, 20cm hill spacing using machine seeder. Accumulative mean air temperature was positively correlated with stem height, number of pods per plant and yield, otherwise accumulative rainfall was negatively correlated with ones. A highly significant negative correlation was showed between number of seedling stand per unit $area(m^2)$ and number of branches, number of pods per plant, grain weight per plant and yield. Yield was positively correlated with number of branches, number of pods per plant and grain weight per plant.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.225-231
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• 1997

This study was conducted to evaluate the growth and yield by sowing times and spacing using machine seeder on Coix Lachryma-jobi L. var ma-yuen $S_{TAPF}$. Adlay was seeded at four different dates (April 20, May 5, May 20 and June 5). Planting spaces were controlled by the seed roller of tractor drill seeder attached to tractor at three spacing ($60{\times}15cm,\;70{\times}15cm\;and\;80{\times}15cm$). The results were summarized as follows. Required days to emergence and days to anthesis were shortened as sowing date was late. But days to maturity were prolonged when sowing date was late. The accumulated temperature increased such as required periods increased. In growth characteristics, culm length was significantly different at different sowing times. But all growth characteristics was not affected by different spacings. In yield components, 1,000 grain weight and ripening rate were significantly different at different sowing times, also the number of tillers and branches was significantly affected at different spacings. Grain yield/ha was significantly different at different sowing times. But it was not significantly different at different spacings. Thus, in order to improve the yield of adlay using drill seeder, if it is not frost, sowing should be done as early as possible. As a result, suitable sowing time was April 20 with spacing at $60{\times}15cm$ using machine seeder in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.1-7
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• 2003

In spite water direct seeding cultivation of rice has advantages in terms of laborsaving and cost-down, it demonstrates uneven seedling establishment and difficult weed management. To select an applicable mat for mulching system of water seeded rice, weed occurrence, growth and yield performances of rice, and soil temperature were evaluated in several kinds of biodegradable mulching material. Field studies were conducted at the experimental farm of National Crop Experiment Station in 1999 and 2000. Among the mats tested in 1999, Safer-mat had the greatest effect on inhibiting weed occurrence and Lawn-mat demonstrated the least efficacy of weed control (EWC) value. In Safer-mat treatment, Ludwigia prostrata was the dominant weed species but Echinochloa crus-galli was not observed. Different kinds of mulching material from the mats studied in 1999 were tested in 2000. Biodegradable polyester (PES) coated on the recycled paper for newspaper press (RP) treatments showed similar or higher EWC values than non-mulched broadcast seed rice with 2 times of herbicide application (BC-herbicide) and Safer-mat that was the most effective mat on preventing weed appearance in 1999. Immediately after mat mulching on the surface of paddy soil, five pregerminated rice seeds were manually sown in each 3cm-hole formerly punctured at 30${\times}$14 cm spacing in 2000. All the 3 kinds of mulching material tested in 2000 had better seedling stand than BC-herbicide treatment. Rice yield in PES coated with 10 thickness on RP (PES10 $\mu\textrm{m}$＋RP) was a little higher than in BC-herbicide treatment but the former produced less panicles in unit land area than the latter. PES10 $\mu\textrm{m}$＋RP demonstrated a great effect on raising soil surface temperature than non-mulching treatment throughout the period of seedling establishment.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.121-127
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• 2023

A 500 km/h linear motor high speed terrestrial transportation service is planned to launch 2027 in Japan. In order to support 5G service in the train, the Sub-carrier spacing frequency of 30 kHz is planned to be used instead of common 15 kHz sub-carrier spacing to mitigate Doppler effect in such high-speed transportation. In addition, to increase the cell size of 5G mobile system, plural Base Station antenna will transmit the identical Down Link (DL) signal to form the expanded cell size along the train rail. In this situation, forward and backward antenna signals will be Doppler shifted by reverse direction respectively and the receiver in the train might suffer to estimate accurate Channel Transfer Function (CTF) for its demodulation. In this paper, Delay and Doppler Profiler (DDP) based Channel Estimator is proposed and it is successfully implemented in signal processing simulation system. Then the simulated performances are compared with the conventional Time domain linear interpolated estimator. According to the simulation results, QPSK modulation can be used even under severe channel condition such as 500 km/h, 2 path reverse Doppler Shift condition, although QPSK modulation can be used less than 200 km/h with conventional Channel estimator.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.512-517
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• 1990

This experiment was conducted to evaluate the tillering behavior of low- and high-tillering rice plants, IR58. a high-tillering cultivar with small panicles showed not only higher tiller number but also earlier tillering, faster tillering rate and longer tillering duration than IR25588. a low-tillering cultivar with large panicles, Tillering ability of IR25588 was only 59% that of IR58, Percent effective tillers was higher in IR25588(85%) than in IR58 (67%), Tillering response to wider spacing was higher in a high-tillering cultivar than in a low-tillering cultivar, Grain yield response to closer spacing (close spacing adaptability) was higher in a low-tillering cultivar than in a high-tillering cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.17-27
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• 1980

All types of weed community became dominant by Monochoria vaginalis (Burm.) Presl. as the nitrogen level increased. The importance value (IV.) of M vaginalis rapidly increased with increasing nitrogen level whereas the LV. of other weed species decreased. At the 10 $\times$ 10cm plant spacing, M. vaginalis was almost totally suppressed at all nitrogen levels. At the 20 $\times$ 20cm plant spacing, the degree of suppression declined with increasing nitrogen level. At the 30 $\times$ 30cm plant spacing, there was no suppression of M vaginalis at the highest nitrogen level. The yield obtained at the 10 $\times$ 10cm plant spacing when M. vaginalis was present was not significantly different from that obtained from the weed free plot for all rice cultivars while it was significantly reduced by M vaginalis competition at the 20 $\times$ 20cm and 30 $\times$ 30cm plant spacings. The difference in yield caused by M vaginalis competition was primarily due to a reduction in the number of panicles at all nitrogen levels. There was a high negative correlation between grain yield and weed weight at heading. The yield reduction due to weed competition varied depending upon the nitrogen level.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.659-665
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• 2000

In this paper a platoon merging control system is considered as a remotely located system with state represented by a stochastic process. in the system it is common to encounter situations where a single decision maker controls a large number of subsystems and observation and control signals are sent over a communication channel with finite capacity and significant transmission delays. Unlike a classical estimation problem where the observation is a continuous process corrupted by additive noise there is a constraint that the observation must be coded and transmitted over a digital communication channel with fintie capacity. A recursive coder-estimator sequence is a state estimation scheme based on observations transmitted with finite communication capacity constraint. in this paper we introduce a stochastic model for the lead vehicle in a platoon of vehicles in a lane considering the angle between the road surface and a horizontal plane as a stochastic process. In order to merge two platoons the lead vehicle of the following platoon is controlled by a remote control station. Using the observation transmitted over communication channel the remote control station designs the feedback controller. The simulation results show that the intervehicle spacings and the deviations from the desired intervehicle spacing are well regulated.