• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.386-391
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• 1997

A study was carried out to investigate the variation of heading date and related yield components at Honam Agricultural Experiment Station in Korea. The treatments were consisted of five transplanting time: from May 5 to July 5 at 15-day intervals, and six cultivars: two early-maturing, two mid-maturing and two late-maturing cultivars. The results showed that variation of heading at different transplanting time was not significant at transplanting after June 5 in early-maturing cultivars, and days of heading from seeding for all tested cultivars were shorter in later transplanting times. The yield components such as numher of spikelcts, percentage of ripened grain and 1.000 grain weight were found to he great on May 5 in early-maturing cultivars and on June 5 in mid-and late-maturing cultivars. Yield was maximized at transplanting of May 20 in early maturing and on June 5 in mid-and late-maturing cultivars. When transplanting time was late, the yield difference hetween early maturing cultivars and late nldtunng ones showed 44 to 77kg/10a in the transplanting of June 20, and 26~30kg/10a in the transplanting of July 5 indicating that the late-maturing cultivars take more advantage than early-maturing ones.

• Journal of Navigation and Port Research
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• v.44 no.5
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• pp.423-429
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• 2020

A ship's automatic steering system is the basis for addressing control difficulties related to course-changing and course-keeping during navigation through heading angle control, and is a link in realizing unmanned and autonomous ships. This study proposes a robust RCGA-based linear active disturbance rejection controller (LADRC) design method considering environmental disturbances, measurement noise, and model uncertainties in designing a ship heading controller for use when the ship is sailing. The LADRC consisted of a transient profile, a linear extended state observer, and a PD controller. The control gains in the LADRC with the linear extended state observer were adjusted by RCGAs to minimize the integral of the time-weighted absolute error (ITAE), which is an evaluation function of the control system. The proposed method was applied to ship heading control, and its effectiveness was validated by comparing the propulsive energy loss between the proposed method and a conventional linear PD controller. The simulation results showed that the proposed method had the advantages of lower propulsive energy loss, more robustness, and higher tracking precision than the conventional linear PD controller.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.522-526
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• 2015

Generally, underwater unmanned vehicle have adopted an inertial navigation system (INS), dead reckoning (DR), acoustic navigation and geophysical navigation techniques as the navigation method because GPS does not work in deep underwater environment. Even if the tactical inertial sensor can provide very detail measurement during long operation time, it is not suitable to use the tactical inertial sensor for small size and low cost UUV because the tactical inertial sensor is expensive and large. One alternative to INS is attitude heading reference system (AHRS) with the micro-machined electro mechanical system (MEMS) inertial sensor because of MEMS inertial sensor's small size and low power requirement. A cost effective and small size attitude heading reference system (AHRS) which incorporates measurements from 3-axis micro-machined electro mechanical system (MEMS) gyroscopes, accelerometers, and 3-axis magnetometers has been developed to provide a complete attitude solution for UUV. The AHRS based MEMS overcome many problems that have inhibited the adoption of inertial system for small UUV such as cost, size and power consumption. Several evaluation experiments were carried out for the validation of the developed AHRS's function and these experiments results are presented. Experiments results prove the fact that the developed MEMS AHRS satisfied the required specification.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.124-131
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• 1995

In order to find out optimum seed production date according to different defoliation and flooding period of Italian ryegrass, this studies with Tetrone were canied out on the experimental field of Honam Crop Experiment Station from 1986 to 1988. Treatments included cutting date of Nov. 20 and Apr. 10 and flooding period of 5-25 days. In soil after experiment, organic matter, phosphate and silicate content increased, but potassium content decreased 0.16% than that before experiment. Heading and maturing date of Nov. 20 cutting were same with those of non cutting, those of Apr. 10 cutting lates 6 days to heading date and 2 days to maturing date. Plant height and culm length of Nov. 20 cutting were sirniller to those of non cutting, those of Apr. 10 cutting were shorter and panicle length have no difference between non cutting and cutting. Lodging of cutting treatment was reduced than that of non cutting. Lodgin was increased as flooding period was long, also loding of all treatment occured at 30 days after heading. Two cutting times of Nov. 20 and Apr. 10 have the most fresh yield, while non cutting have the most dry matter yield. Optimun seed productin date was considered to suitable when 35 days after heading (Jun. 14), at this time, seed production was 1,640 to 2,640 kg/ha. Also if flooding j u r y have, seed production was good between 10 days and 15 days after flooding.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.29-35
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• 2008

In this paper, a new guidance law to reduce sensitivity to the initial heading errors is proposed. In order for shaping the input weights over the flight, we introduce the distribution functions expressed in terms of time-to-go and its inverse term. By applying the optimal control theory with the synthesized weights, the homing guidance law is derived. Also the characteristics of the proposed law are examined. Various computer simulations show the good performance of the proposed guidance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.259-267
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• 2010

This study was performed at Rice and Winter Cereal Crops Department of NICS during 2007 and 2008 to investigate the characteristics of rice leaf emergence and to obtain basic data which can be used for rice growth simulation model by which we can forecast rice growth stage and heading date accurately under different cultivars, transplanting date, and climatic conditions. To confirm leaf emergence rate according to rice maturing ecotype, we surveyed the leaf emergence rate and heading date of Unkwangbyeo, Hwayoungbyeo and Nampyeongbyeo which are early maturing, medium maturing and medium-late maturing cultivars, respectively, according to seedling raising duration and transplanting time. When seedling duration was 15 days, the growth duration between transplanting time and completion of flag leaf emergence on main culm were 51.5~78.3 days in Unkwangbyeo, 55.3~87.9 days in Hwayoungbyeo and 58.4~98.4 days in Nampyeongbyeo, respectively. When seedling duration was 30 days, they were 50.1~75.5 days in Unkwangbyeo, 52.4~84.7 days in Hwayoungbyeo and 56.4~93.8 days in Nampyeongbyeo, respectively. As transplanting time delayed, the emerged leaf number after transplanting decreased in all rice cultivars. The cumulative temperature between transplanting time to completion of flag leaf elongation on main culm were $1,281^{\circ}C{\sim}1,650^{\circ}C$ in Unkwangbyeo, $1,344^{\circ}C{\sim}1,891^{\circ}C$ in Hwayoungbyeo and $1,454^{\circ}C{\sim}2,173^{\circ}C$ in Nampyeongbyeo, respectively. Leaf emergence rate on main culm were precisely represented by equation, y = $y_0$ + a / [1 + exp( - (x - $x_0$) / b)]^c, when we used daily mean temperature as variable.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.322-322
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• 2022

Hay and haylage as forage are increasing in preference for cattle feed. Triticale (X Triticosecale Wittmack) is growing up as a forage crop due to its high production and feed value in South Korea. It is difficult to determine the harvesting stage of triticale for producing hay or haylage with the highest forage value and quality because feed and nutritional value by growth stages of triticale were not known in South Korea yet. In this study, we analyzed forage values, pH, and contents of organic acid, to confirm feed value and quality by growth stages of triticale. The triticale 'Joseong' was sown in the spring of 2022. The sample was prepared in 5 stages: seedling stage, booting stage, heading stage, 10 days after heading, and 20 days after heading. The triticale was dried under 10% and to about 50% moisture for hay and haylage respectively, and then both triticales were fermented anaerobically at room temperature for 40 days. The pH value in all hay and haylage became lower as the triticale was grown up, although the pH value of all triticale hays and haylages ranged between 7.05-5.68. The content of lactic acid in all triticale hays was almost meaningless. The contents in the haylage of the seedling stage were the highest (2.39%) among the haylages, even though those of 20 days after the heading stage (1.67%) were the lowest, which showed a similar tendency with pH value. Conclusionally, the results implied that the feed value and quality of triticale haylage were affected by harvesting time but not hay.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.3-7
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• 1996

Effects of the nitrogen application time and amounts on the nitroger. uptake and recovery of fertilizer nitrogen applied at panicle formation stage was investigated in connection with the growth and yield of rice drill-seeded in puddle-soil. silt loam of Jeonbuk series. Urea was applied as nitrogen source. Nitrogen uptake and recovery of fertilizer nitrogen by rice plant was highest in the treatment applied nitrogen at 20 days before heading. Culm length, internode length (4th and 5th) and lodging index were increased by earlier application time and higher level of nitrogen. but filled grain ratio and 1,000 grain weight showed the opposite trend Panicle number per square meter and grain number per panicle was significantly decreased in nitrogen application at 10 days before heading. Rice yield was the highest in 33kgN/ha(conventional amount at 20days before heading, and yield in 26kgN/ha(80% of conventional amount) at 20 days before heading and in 33kg/ha at 15days before heading were nearly the same as conventional treatment.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.80-80
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• 2022

Estimation of heading date of paddy rice is laborious and time consuming. Therefore, automatic estimation of heading date of paddy rice is highly essential. In this experiment, deep learning classification models were used to classify two difference categories of rice (vegetative and reproductive stage) based on the panicle initiation of paddy field. Specifically, the dataset includes 444 slanted view images belonging to two categories and was then expanded to include 1,497 images via IMGAUG data augmentation technique. We adopt two transfer learning strategies: (First, used transferring model weights already trained on ImageNet to six classification network models: VGGNet, ResNet, DenseNet, InceptionV3, Xception and MobileNet, Second, fine-tuned some layers of the network according to our dataset). After training the CNN model, we used several evaluation metrics commonly used for classification tasks, including Accuracy, Precision, Recall, and F1-score. In addition, GradCAM was used to generate visual explanations for each image patch. Experimental results showed that the InceptionV3 is the best performing model in terms of the accuracy, average recall, precision, and F1-score. The fine-tuned InceptionV3 model achieved an overall classification accuracy of 0.95 with a high F1-score of 0.95. Our CNN model also represented the change of rice heading date under different date of transplanting. This study demonstrated that image based deep learning model can reliably be used as an automatic monitoring system to detect the heading date of rice crops using CCTV camera.

• Journal of Auto-vehicle Safety Association
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• v.8 no.1
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• pp.13-18
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• 2016

More than 80 percent of traffic accidents related with lane departure believed to be the result of crossing the lane due to either negligence or drowsiness of the driver. Lane-departure related accident in the highway usually involve high fatality. Even though LDWS is believed to prevent accident 25% and reduce fatalities by 15% respectively, its effectiveness in performance is yet to be confirmed in many aspects. In this study, the vehicle lateral locations relative to warning zone envelop (earliest and latest warning zone) defined in ISO standard, ECE and NHTSA regulations are compared with respect to various factors including delays, vehicle speed and vehicle heading angle with respect to the lane. Since LDWS is designed to be activated at the speed over 60 km/h, vehicle speed range for the study is set to be from 60 to 100 km/h. The vehicle heading angle (yaw angle) is set to be up to 5 degree away from the lane (abrupt lane change) considering standard for lane change test using double lane-change test specification. The TLC is calculated using factors like vehicle speed, yaw angle and reaction time. In addition, the effect of vehicle type and reaction time have been considered to assess LDWS safety.