• Journal of Ocean Engineering and Technology
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• v.34 no.2
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• pp.77-88
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• 2020

In this study, heading characteristics and heading control performances were evaluated to achieve the wave shield effect. The wave shield effect originating from heading control reduces the relative motions of moored vessels in a floating liquefied natural gas bunkering terminal (FLBT). Therefore, loading and off-loading performances are improved through reduced relative motion. For the objective of this study and efficiency of the analysis, a simplified model was used that assuming no relative motion of the moored vessels in the FLBT. The simplified model involved modeling the environmental loads and inertia of several floating bodies, including FLBT, into the environmental loads and inertia of a single vessel. The simplified model was validated through comparisons with model tests. With the simplified model, heading characteristics and heading control simulations were performed using low-frequency planar motion equations. The heading characteristics and heading control performances of FLBT were analyzed through the results of simulations under the expected environmental conditions. The capacity of the tunnel thrust for the heading control performance was confirmed to be adequate for improvement of the loading and off-loading performances using the wave shielding effects under the operation conditions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.4
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• pp.297-302
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• 2002

This study was carried out to compare the agronomic characteristics, forage yield, and quality of four sorghum $\times$ sudangrass hybrids at Yonam College of Agriculture Experimental Livestock Farm, Sunghwan in 2001. The four recommended hybrids used in this study were ‘SXl7’ and ‘877F’(heading type), and ‘TE Evergreen’ and ‘Turbo 9’(headless type). sugar content or heading hybrids(SX17 and 877F) were higher then that of headless hybrids(TE Evergreen and Turbo 9). SX17 had resistance to lodging, while all hybrids had resistance to foliar disease and insect. Dry matter(DM) and total digestible nutrients (TDN) yields of heading hybrids were higher then those of headless hybrids. Among sudangrass hybrids, DM and TDN yields of 877F were the highest(21,007 and 12,276kg/ha). The crude protein of Turbo 9(10.5%) was higher than other hybrids. Neutral detergent fiber(NDF) content of headless hybrids were higher than that of heading hybrids, while acid detergent fiber(ADF) and acid detergent lignin(ADL) contents of headless hybrids were lower than those of heading hybrids. Calculated TDN of headless hybrids were higher than that at heading hybrids. Cellulase digestible of organic matter of dry matter (CDOMD) of headless hybrids also were higher then that of heading hybrids. Results of this experiment indicates that heading hybrid was better than headless hybrid in the agronomic characteristics and forage yield of sorghum $\times$ sudangrass. However heading hybrid was lower than leafless hybrid in quality of sorghum $\times$ sudangrass.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.3
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• pp.293-300
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• 2012

This experiment was carried out to compare the agronomic characteristics, forage yield and quality of sorghum ${\times}$ sudangrass hybrid at two locations (Sungju and Cheonan) in 2009. The experiment was a randomized complete block design with three replications. The eight recommended hybrids used in this experiment were 'Sordan 79', 'SX17', 'Honey chew', 'Honey grazer', 'G7', 'Jumbo', 'Green star' and 'GT56' hybrids. The heading of four hybrids were headed at both region, Sungju and Cheonan. There are no big differences in general agronomic characteristics among hybrids, but brix scale of heading and BMR (brown mid rib) types were higher than those of other hybrids. Dry matter (DM) and plant height of heading type hybrids were higher than those of headless types. The fresh, DM and TDN (total digestible nutrients) yields of heading type hybrids were also higher than those of headless types, and BMR types were lower than others. The crude protein and crude ash contents of headless hybrids were higher than those of heading hybrids, while its non-fiber carbohydrate (NFC) content showed the opposite results. The acid detergent fiber (ADF) and NFC contents of BMR types were lower than others. The results of this experiment indicates that heading hybrids were more higher than headless hybrids in the agronomics and forage yield of sorghum ${\times}$ sudangrass. However heading types were lower headless types in quality of sorghum ${\times}$ sudangrass. And BMR hybrids were also high quality of sorghum ${\times}$ sudangrass hybrid because of higher brix content and lower ADF content among tested hybrids.

• Journal of Ocean Engineering and Technology
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• v.33 no.2
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• pp.178-188
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• 2019

When burying underwater cables using robots, heading control is one of the key functions for the robots to improve task efficiency. This paper addresses the heading control issue for URI-T, an ROV for underwater construction tasks, including the burial and maintenance of cables or small diameter pipelines. Through modeling and identifying the heading motion of URI-T, the dynamic characteristics and input limitation are analyzed. Based on the identification results, a PD type controller with appropriate input treatment is designed for the heading control of URI-T. The performance of the heading controller was verified in water tank experiments. The field applicability of the proposed controller was also evaluated through the sea trial of URI-T at the East Sea, with a water depth of 500 m.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.468-472
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• 2001

In order to know the relationship between the accumulated temperature distribution and barley growth characteristics, average, early and late heading years were analyzed. Among 24 year's crop situation test 1976, 1979, 1989, 1990, 1998 were sorted to early heading years and 1977, 1980, 1984, 1996 to late heading years. About $650^{\circ}C$ of accumulated temperature from October to December was enough to get average year's heading date in barley. While 62$0^{\circ}C$ of accumulated temperature were not enough for average heading, 67$0^{\circ}C$ of accumulated temperature accelerated barley heading. 78$0^{\circ}C$ of accumulated temperature from October to February, were enough to get average year's heading date in barley. while $650^{\circ}C$ of accumulated temperature were not enough to, 78$0^{\circ}C$ of accumulated temperature accelerated barley heading. Temperature pattern types in early heading years were distinguished by three types : high temperature type before winter(I), high temperature type in winter-regrowth stage(II), high temperature type in tillering stage(III). On the other hands, temperature pattern types in late heading years were divided to two types : low temperature type in winter-regrowth stage(I), low temperature type in tillering stage(II). Barley heading was mainly influenced by temperature before winter and winter-regrowth stage. Yields of early heading years were higher than that of late heading years and yield was heavily influenced by the number of spikes per square meter.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.3
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• pp.213-220
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• 2002

The growth characteristics, forage yields and nutritive values of heading and headless types of sorghum $\times$ sudangrass(Sorghum bicolar L.) hybrids were examined to evaluate the adaptability of new cultivars at Suwon and Chunahn for two years from 2000 to 2001 in a randomized complete block design with three replications. Eleven cultivars of heading type and 4 cultivars of headless type were used in this study. The dry matter(DM) yield of AG 2501 was highest in the heading type cultivars, and PAC F8350 in the headless type cultivars, respectively. The DM yields of heading types were slightly higher than those of headless types but there were not significantly different. Early growth and regrowth characteristics of heading type was highest in AG 2501 and GW 9110G, respectively. GW 9110G and DMD were early heading types, and AG 2501 and GW 9161F were middle heading types. AG 2501 was longest and GW 9161F was shortest in plant height. Cultivars with long leaf length were appeared to be larger fur leaf width and stem diameter. Brix content was highest in DMD as 9.7%, and disease and insect resistances were not significantly different among the heading types. Early growth of headless type cultivar, PAC F8350 was slightly lower than that of Jumbo but stronger in regrowth, wider in leaf width and stem diameter, and stronger in lodging. Comparisons of growth characters between heading and headless types of cultivars were not easy in general but between them, brix contents of heading types ranging from 6.7 to 7.9% were greatly higher than those of headless types ranging from 3.6 to 3.9%. Nutritive values such as crude protein, ADF, NDF and digestibility of headless type cultivars were higher than those of heading types. In conclusion, of heading type cultivars, GW 9110G, AG 2501, DMD and GW 9161F, and of headless type cultivars, Jumbo and PAC F8350 were recommended as high yielding cultivars with good adaptability in domestic environment.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.4
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• pp.225-234
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• 2022

The flow field measurement above whole area of the flight deck on 'Landing Platform Helicopter (LPH)' was performed by using PIV system in wind tunnel. In various heading angle conditions (0deg, -30deg, -45deg, -60deg, -75deg and ±90deg), the velocity fields such as U velocity & V velocity were measured at three different height above flight deck. Due to the geometrical characteristics of several bodies like deck, crane and super-structure, various vortex were generated. When the heading angle is 0deg, the deck edge vortex by flight deck and massive separation by super-structure were clearly observed by visualization with smoke and PIV, respectively. In other heading angles, the acceleration of flow in space between crane and super-structure were detected. And area with flow separation by super-structure is directly related to the heading angle of vessel.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.3
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• pp.195-202
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• 1993

This experiment was carried out to investigate the eft'ects of different seeding dates on the agronomic characteristics, forage yield and quality of fall sown cats(Avena sativa L.). The experiment was conducted at the forage experimental field, Seoul National University. Suweon in 1990. The results obtained are summarized as follows; 1. Present data indicated that plant and ear heights were decreased as the seeding date was delayed. Dry matter accumulation was increased due to the higher plant and ear heights. 1. When oats was seeded on August 20. the first heading and 50% heading dates were recorded on October 4 and 15, respectively. And when oats was seeded on August 25. the first heading and 5 0'!4 heading dates were observed on October 13 and 18. respectively. As seeding date was delayed for one day. the heading date was delayed for two days. 3. The dry mattcr percentage of oats seeded on August 20 was 20.1%, but that of oats seeded after August 10 was 15.1 to 16.7%. 4. According to the contents of CP. ADF and NDF, oats seeded on August 20 and 25 was evaluated to be the 3rd or 4th grade hay. and the other oats sceded after August 15 was recorded the 2nd or 3rd grade hay as proposed by AFGC. 5. There are no significant dry matter yield differences among the seeding dates of oats such as August 20, 25 and 30. but a significant yield difference was recorded between oats seeded in August and September. The same trend as the dry matter yield was observed in in vitro digestible dry matter and crude protein yields of oats seeded in August and September. According to the results. early seeding of early matuaring oats may be a better option than late seeding after August 30 for silage or hay production following silage corn harvest in the middle northern area of Korea.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.179-184
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• 2001

To investigate the effects of harvesting times on physicochemical and milling properties of rice, milling tests were performed applying laboratory milling systems. Milling and head rice yields were highest in rice harvested at the 45 days after heading at 76.49 and 94.43%, respectively. Milled rice grain harvested 45 days after heading showed the highest minimum viscosity, as shown in the amylogram curves, as well as the lowest consistency viscosity. Protein and amylose contents were highest in rice harvested at 35 days after heading, whereas the instrumental taste score was highest 45 days after heading.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.3
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• pp.145-156
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• 2024

Due to climate change and the expansion of cultivation areas through the use of reclaimed land, changes in the selection of Italian ryegrass (Lolium multiflorum L.) varieties are anticipated. This study was conducted to compare the growth characteristics before overwintering, productivity, and feed value of eight Italian ryegrass varieties with different maturing stages under the same cultivation conditions. The variety 'Lm4ho', a medium-maturing type, showed superior growth characteristics before overwintering, including plant height, leaf length, and leaf width. The heading date was advanced in all varieties, with a greater degree of advancement observed in varieties with earlier heading dates. When harvested at the heading stage of the early-maturing types, the dry matter yield of the medium-maturing types was not significantly different from that of the early-maturing types. However, when harvested at the heading stage of the medium-maturing types, the dry matter yield was higher than that of the early-maturing types. Specifically, 'Lm4ho' produced 2,518 kg/ha more than 'Kowinearly'. The late-maturing variety IR901 and the medium-maturing varieties 'Lm4ho' and 'Kowinmaster' showed statistically superior dry matter yields. In terms of forage value, including crude protein (CP), total digestible nutrients (TDN), and relative feed value (RFV), the medium- and late-maturing types outperformed the early-maturing types. Notably, 'Lm4ho', 'IR 901', and 'Hwasan 104' were evaluated as suitable varieties for high-quality forage production. These results suggest that medium-maturing varieties may be suitable for double cropping in the central regions due to climate change. We propose that future breeding of Italian ryegrass should expand from focusing on cold tolerance and early-maturing varieties to include medium- and late-maturing varieties that consider both productivity and quality.