• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.39-46
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• 1985

Heading time was hastened by the combination of seeding time and longday treatment in order to elucidate the effect of early heading on earliness in maturity, vegetative growth and grain yield in five barley varieties and four wheat varieties under field conditions in Suwon, Korea, 1978-79. About 15 days of earliness in heading accelerated only 2 to 6 days in maturity. Furthermore, the duration of grain fill was not much prolonged comparing with the extension of days from heading to maturity, because of the extension of periods from heading to anthesis at lower temperature resulting in somewhat greater final grain weight. Periods from heading to anthesis and from anthesis to maturity were negatively correlated with the air temperature. In early heading, leaf area at 10 days after anthesis and net assimilation rate were much limited, and although leaf area duration got larger, presumably, it could not make up for the reduction of grain yield. Grain yield per plant reduced noticeably in early heading. This was mainly caused by the reduction of spike number and grain number per spike.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.431-437
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• 2023

This study evaluated the ecological characteristics related to spike heading time of three Korean foxtail millet cultivars, i.e., one early and two late maturities, and a finger millet cultivar in the north-central region of the Korean Peninsula, Kangwon Province. The changes in heading time occurred due to the changes in planting time from mid-May to late June. The heading time of the early-maturity cultivars was early August, with 80 days required for heading (DH) for the mid-May planting; late August, with 65 DHs for the late June planting; and mid-late August, with 100 DHs and mid-October, with 65 DHs, respectively, for the late-maturity cultivars. The accumulated temperature at heading time ranged from 1,700℃ of mid-May planting to 1,500℃ of late June planting in the early-maturity cultivars. In contrast, it ranged from 2,100℃ to 1,900℃ in the late-maturity cultivars. The photoperiod at heading time ranged from 14.0 h to 13.2 h in the early-maturity cultivars, whereas it was from 13.2 h to 12.5 h in the late-maturity cultivars. Considering that the limiting heading time of Korean foxtail millet and finger millet in the northern region of Kangwon Povince is late August, the limiting accumulated temperature at the heading time was evaluated to be approximately 1,500℃ and 2,000℃ for early and late-maturity cultivars, respectively. The mean daily temperature from planting to heading time showed a negative correlation with the DH, which was shortened with the increase in mean daily temperature. This suggests that delaying the planting time from May to June in the north-central region of the Korean Peninsula increases the mean daily temperature during vegetative growth periods, resulting in the decrease of the DH and the accumulated temperature.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.59-64
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• 2004

In this paper, the error compensation method of the low-cost IMU is proposed. In general, the position and attitude error calculated by accelerometers and gyros grows with time. Therefore the additional information is required to compensate the drift. The attitude angles can be bound accelerometer mixing algorithm and the heading angle can be aided by single antenna GPS velocity. The Kalman filter is used for error compensation. The result is verified by comparing with the attitude calculated by Attitude Heading Reference System with Micro Electro Mechanical System for a basis

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.221-226
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• 2000

This experiment was designed to assess changes in yield difference between waxy (IWR) and non-waxy (INWR) near isogenic rice by evaluating the translocation and accumulation of assimilates in different parts of the rice plants after heading stage under different fertilizer application. Nitrogen content of culm in both IWR and INWR decreased rapidly from 35 days before heading to flowering time and after then it was maintained constantly, while the nitrogen content of leaf blade was continually reduced. Sugar content of leaf blade in IWR decreased steadly by 10 days after heading, but that in INWR increased 20 days after heading. There was no difference in starch content of culum between IWR and INWR from 35days before heading to heading, but that of culm of IWR increased again after heading. Dry weight of IWR plant was less reduced during ripening as compared with INWR. The dry weight of culm was not significantly different between two isogenic lines.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.163-170
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• 2016

Heading time is important element for yield and quality in crops. Among day length and temperature which influence on heading, temperature effect has not been investigated well. To investigate temperature effect on heading, heading date and plant growth characters were checked under the low and high temperature conditions in short day length. Analyzing heading date of six Korean varieties under the high and low temperature condition, heading date of varieties were delayed under low temperature. In the low temperature condition, dry weight and area of leaf were reduced. Varieties showing more delay of heading under low temperature also showed more reduction in leaf area. After selecting three varieties showing significant difference in leaf growth and heading date under different temperature conditions, nutrient contents of plant were analyzed. Nitrogen content was reduced in leaf and shoot under the low temperature condition. OsNRT2.3, nitrate transporter, was significantly down regulated in varieties showing more heading delay. Available phosphate content was decreased in leaf, but increased in shoot due to reduction of phosphate mobility. OsPT1, phosphate transporter regulating phosphate uptake, was more down regulated in varieties showing more heading delay. OsPT6, phosphate transporter regulating phosphate transport in plant, was also significantly down regulated in those varieties. With these data, we expected that active nitrogen and available phosphate uptake and transport in plant would increase leaf growth then might reduce heading delay under the low temperature condition.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.100-106
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• 1984

Traditional methods for estimating the location of underwater target, i.e. the triangulation method and the wavefront curvature method, have been utilized. The location of a target is defined by the range and the bearing, which estimates can be obtained by evaluating the time delay between neighboring sensors. Many components of error occur in estimating the target range, among which the error due to the fluctuation of heading angle is outstanding. In this paper, the wavefront curvature method was used. We considered the error due to the heading fluctuation as the $\beta$-density process, from which we analized the range estimates with $\beta$-density function exist in some finite limits, and its mean value and variation are depicted as a function of true range and heading fluctuation. Given heading angles and sensor separation, maximum estimated heading errors are presented as a function of true range.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.7
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• pp.1068-1079
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• 2008

Tilt and heading angles information of a remotely operated vehicle (ROV) are very important in underwater navigation. This paper presents a low.cost tilt and heading estimation system. Three single.axis rate gyros, a tri-axis accelerometer, and a tri-axis magnetometer are used. Output signals coming from these sensors are fused by two Kalman filters. The first Kalman filter is used to estimate roll and pitch angles and the other is for heading angle estimation. By using this method, we have obtained tilt (roll and pitch angles) and heading information which are reliable over long period of time. Results from experiments have shown the performance of the presented system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.487-491
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• 1990

This experiment was conducted to investigate the cultural practices for improvement of rice grain quality under different cultivation times and fertilizer levels at panicle initiation, heading and different drainage times after heading. The obtained results could be summarized as follows. In consideration of brown rice whole kernel form, and analyzed physico-chemical properties cultivation time required the optimum season before June 5. Feltilizer level at panicle initiation and heading needed 3kg/10a or less. Drainage time desired late drainage at 30-40 days after heading.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.165-168
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• 1988

This study was conducted at the rice field of Livestock Experiment station, Suweon to investigate the effects of harvesting time on forage production and quality of rye (Secale cereale L.) on paddies. The results obtained are summarized as follows; 1. Fresh matter yield was peaked at the 10 days (May 10) after heading, however, dry matter yield was increased in proportion to maturity. 2. Digestibility (in vitro) showed the 83-77% by heading stage (Apr. 25-30) but decreased to 66-58% after heading stage. 3. Digestible yield reached to maximum level, 619.2 kg/lOa at the 10 days after heading (May 10). 4. The content of crude protein and crude fat in forage rye was decreased with advancing the maturity. 5. The lactic acid content of rye silage ranged from 1.3% to 2.0%.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.331-339
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• 1975

This experiment was carried out to obtain some imformations about the ecological variations of the heading time of the newly breeded Indica x Japonica varieties/pedigrees according to the seasonal changes of the seeding date. day length and temperature. The results obtained are summarized as follows; 1) At all varieties. days to heading showed a straight reduction according as the seeding time was delayed. 2) At the group of Japonica varieties. the days to heading of early maturing varieties were much shortened and that of medium or late maturing varieties were little or not shortened under high temperature condition but at the group of Indica ${\times}$ Japonica va rieties/pedigrees. days to heading were significantly elongated under high temerature condition. 3) At the group of Japonica varieties. the effect of the short day condition on the days to heading was significantly high at the medium and the late maturing varieties than at the early maturing varieties. however. the short day effect on the reduction of days to heading was not related with the earlyness of each varieties at the group of Indica ${\times}$ Japonica varieties/pedigrees. 4) Days to heading of all varieties under the high temperature condition were longer than that under the ordinary culture. On the other hand, the days to heading of Japonica varieties under the short day treatment were shorter than the days to heading of ordinary culture but at the group of Indica x Japonica varieties/pedigrees. the days to heading under the short day treatment were longer than ordinary culture. 5) At both varieties groups. the days to heading at each seeding time were significantly correlated with days to heading at ordinary cultivation. fl) At the group of Japonica varieties. relatively high correlation(p=0.1) was recognized between the days to heading by delay of seeding time, but at the group of Indica ${\times}$ Japonicava rieties/pedigrees, correlation between the ordinary heading date and the shortening rate of days to heading was very low.