• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.2
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• pp.91-96
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• 2006

This experiment was carried out in order to examine the winterhardiness, heading date, fresh and dry matter yeild of Festulolium braunii, a hybrid of Festuca pratensis and Lolium multiflum, which is newly introduced in Korea. This experiment was performed at National Livestock Research Institute in Suwon and Namwon from September 2004 to July 2005. The results are as follows. 'Fleurial', 'Boxer', and 'Perun' showed stronger winterhardiness than 'Hwasan 101', which is one of the strongest in the winterhardiness hybrids. Therefore, we do not see there is any problem in winterhardiness when these hybrids are cultivated in Korea. The hybrids are turned out to be mid and late maturing hybrid. The average heading dates of the three hybrids were May 25 in Namwon and May 27 in Suwon. These dates are lower($1{\sim}3$ days) than that of Hwasan 101. They showed $91{\sim}96cm$ in leaf length at 1st cutting times which are comparatively long. This experiment also disclosed that their lodging and regrowth are strong and excellent. We also found out that there are significant difference between regions and hybrids in the total fresh yield per ha. The average fresh yield of Suwon was 83,222 kg/ha and that of Namwon was 69,139 kg/ha. We could not see any difference in the dry matter yield affected by region, however, there were significant difference in hybrids(p<0.05). The crude protein contents of the three hybrids indicated very high figures. the crude protein cotents of Perun, Fleurial and Boxer are 18.0% 17.4% and 16.7% respectively. However the ADF (Acid Detergent Fiber) shows $28.1{\sim}29.2%$ which is less contents than 33.2% of Hwasan 101. We found out from this experiment that these three hybrids have excellent feed quality because the NDF (Neutral Detergent Fiber) is decreased by $7{\sim}3.8%$ comparing that the NDF of Hwasan 101 is 58.3%. Also each hybrids contains more crude fat by 1%, a little more chemical composition and less ash contents. Thus we can tern that chemical composition contents of these hybrids are also fittable.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.108-116
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• 2009

In this paper, we propose a Ethernet based audio distribution system with a new L1/L2 hybrid switching scheme, and evaluate its performance. The proposed scheme not only offers guaranteed low latency and jitter characteristics that are essentially required for the distribution of high-quality uncompressed audio traffic, and but also provide an efficient transmission of data traffic on the Ethernet environment. The audio distribution system with a proposed scheme consists of a master node and a number of relay nodes, and all nodes are mutually connected as a daisy-chain topology through up and downlinks. The master node generates an audio frame for each cycle of 125us, and the audio frame has 24 time slotted audio channels for carrying stereo 24 channels of 16-bit PCM sampled audio. On receiving the audio frame from its upstream node via the downlink, each intermediate node inserts its audio traffic to the reserved time slot for itself, then relays again to next node through its physical layer(L1) transmission - repeating. After reaching the end node, the audio frame is loopbacked through the uplink. On repeating through the uplink, each node makes a copy of audio slot that node has to receive, then play the audio. When the audio transmission is completed, each node works as a normal L2 switch, thus data frames are switched during the remaining period. For supporting this L1/L2 hybrid switching capability, we insert a glue logic for parsing and multiplexing audio and data frames at MII(Media Independent Interlace) between the physical and data link layers. The proposed scheme can provide a good delay performance and transmission efficiency than legacy Ethernet based audio distribution systems. For verifying the feasibility of the proposed L1/L2 hybrid switching scheme, we use OMNeT++ as a simulation tool with various parameters. From the simulation results, one can find that the proposed scheme can provides outstanding characteristics in terms of both jitter characteristic for audio traffic and transmission efficiency of data traffics.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.848-857
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• 2018

Recently, around the world, active development of new renewable energy sources including solar power, waves, and fuel cells, etc. has taken place. Particularly, floating offshore wind farms have been developed for saving costs through large scale production, using high-quality wind power and minimizing noise damage in the ocean area. The development of floating wind farms requires an evaluation of the Maritime Safety Audit Scheme under the Maritime Safety Act in Korea. Floating wind farms shall be assessed by applying the line and area concept for systematic development, management and utilization of specified sea water. The development of appropriate evaluation methods and standards is also required. In this study, proper standards for marine traffic surveys and assessments were established and a systemic treatment was studied for assessing marine spatial area. First, a marine traffic data collector using AIS or radar was designed to conduct marine traffic surveys. In addition, assessment methods were proposed such as historical tracks, traffic density and marine traffic pattern analysis applying the line and area concept. Marine traffic density can be evaluated by spatial and temporal means, with an adjusted grid-cell scale. Marine traffic pattern analysis was proposed for assessing ship movement patterns for transit or work in sea areas. Finally, conceptual design of a Marine Traffic and Safety Assessment Solution (MaTSAS) was competed that can be analyzed automatically to collect and assess the marine traffic data. It could be possible to minimize inaccurate estimation due to human errors such as data omission or misprints through automated and systematic collection, analysis and retrieval of marine traffic data. This study could provides reliable assessment results, reflecting the line and area concept, according to sea area usage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.2
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• pp.69-80
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• 2023

This study investigated the differences in barley growth at different growth stages (Dec, Feb, and Apr) and the yield at harvest in three groups (G1, G2, and G3) with different climates. Additionally, we measured meteorological differences between areas during the growing season to determine which factors were related to growth and yield differences. We evaluated the chemical composition of soil and the mineral content in leaves during the heading stages. We also recorded the main constituents, amino acids, and mineral compositions of barley seeds grown in different areas. Tiller number/m² in G1 areas was higher than in G2 and G3 when measured before and after overwintering. However, tiller number/m² and dry aboveground plant parts/m² in G2 and G3 areas were higher than in G1. Regrowth, panicle formation, and heading days in G2 areas occurred slightly later than in G1 and G3. However, there was no difference in chlorophyll content (SPAD value) between groups. The yield in G1 areas was 9~15% less than in G1 and G3. The decrease in yield in G2 areas could be due to lower panicle number, spikelet number, and ripening rate. In addition, the decrease in yield in G2 areas is likely because maximum, minimum, and average daily temperatures during the growing season were lower than those in G1 and G3. However, mineral nutrients in the soil were higher in the G2 area than in G1 and G3. The overall mineral content in plants tended to be higher in G1 areas than in G2 and G3. Mineral content such as Cu, K, Mg, and P in G3 areas and crude protein and most amino acids in G2 areas tended to be relatively low compared to other areas. Thus, the G1 area may be suitable for barley cultivation without adverse impacts on barley yield, main constituents, amino acids, and mineral contents compared to the main producing areas in G3.