• The Korean Journal of Ecology
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• v.22 no.5
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• pp.287-294
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• 1999

During the period from April to October, 1998 the authors investigated the gall development process of Chinese gallnuts (Schelchtendalia chinensis) on sumac (Rhus javanica) at Mt. Goduk near Chonju city in Chonbuk province. The majority (56.8%) of chinese gallnuts were formed on first pinnates and 24.3% on second pinnates of sumac leaves. Galls began to form from the 1st of June and grew slowly until the 24th of June. Galls enlarged rapidly after the 1st of August, but their growth rates decreased after the 26th of August and stopped growing after the 8th of September. Alate viviparous females escaped from galls after the 24th of September. Fundatricies, the second generation in the galls, exuviated three times to become adults on the 24th of June. Fundatrix adults bore 1∼10 eggs in the body and laid 1∼16 nymphs of the second generation. Nymphs of the second generation began to appear on the 17th of June and had matured completely on the 14th∼24th of July. Adults of the second generation bore eggs in the body. Thus the developmental period of the second generation was 27∼37 days. Nymphs of the third generation appeared on the 14th of July and finally alate viviparous females were developed on the 24th of September. During the two months from the beginning of the third generation to the appearence of the final alate viviparous females, there should be at least two generations, that is, the third and fourth generations. The fourth generation seems to begin at about the 20th August because the number of inhabitants (2,859 individuals) in galls on the 26 th of August had increased more than 10 times those (263 individuals) on the 19 th of August. The tannin content of galls was 65.04∼68.23% while that of sumac leaves and stems was 11.56%, 3.49% respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.597-603
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• 1997

Orostachys japonicus, Wasong as herb medicine, has been artificially cultivated as an anti-tumor medicinal. The experiment was carried out to examine the effect of natural daylength as control or night-break treatment (NB) imposed at June 20, July 18 or Aug. 15 on its growth, dry weights of leaf and bract, stem, floret and root, and morphological characters including bolting and floret flowering. After a plant was grown in a 15cm plastic pot containing a 2 : 1 soil : peat moss mixture on May 23, three treatments with above differing night-break had been imposed around midnight up to Nov. 7. The plants were sampled 3 times at the same day forced to night-break and then done 6 times by 2-week interval after the final NB. Plant height and inflorescence length of all the NB increased with delayed NB but declined in comparison with the natural daylength. No. of leaves including bracts showed similar response to plant height although NB given before July 18 showed less leaves and bracts. Stem diameters of NB were continuously increased to middle Sept. to middle Oct. while that of natural daylength decreased after middle Oct. Natural daylength or NB given on Aug. 15 had greater fraction, shoot and total dry weights resulting from increment of leaf and bract up to Aug. or of floret, stem and root after Sept. The earlier NB, the later formation of florets and the less number of flowering florets whereas in natural daylength florets on inflorescence begun to be formed from middle Sept. were sharply increased up to middle Oct. when all the plants were flowered. Bolting was not formed in the plant of the earliest NB of June 20, and thereby no anthesis of florets up to early Nov. It was concluded that year-round cultivation of Orostachys japonicus plants was possible through controlling the NB timing because its bolting and flowering of florets separately occurred.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.298-305
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• 2011

This study was conducted to enhance the stem firmness of standard chrysanthemum 'Baekma' bred in Korea for commercial quality improvement and inhibition of stem breaking during transportation through foliar spray with calcium agents. Calcium agent screening 'Baekma' was examined using $CaCl_2{\cdot}2H_2O$, $Ca(NO_3)_2{\cdot}4H_2O$, and OS-Ca (natural liquid calcium compounds extracted from oyster shell) depending on each concentration (0, 0.001, 0.01, 0.1, and 1.0%, respectively). All calcium agents sprayed with 1.0% caused chemical injury such as stem bending or leaf burn. OS-Ca also showed more sensitive response to chemical injury than the other calcium agents because OS-Ca was absorbed very well by 'Baekma' leaves. Maximum stem firmness measured during the final harvest was greater in OS-Ca than in the other calcium agents. Especially, maximum stem firmness was greatest in 0.01% OS-Ca. However, elastic strength and maximum bending stress were greater in 0.001% OS-Ca than in the others. Thus, OS-Ca ranged from 0.005 to 0.05%, which did not show any chemical injury, was finally selected as the first candidate for hardening the stem of 'Baekma'. The next experiment using OS-Ca was conducted with the concentrations of 0, 0.005, 0.01, and 0.05%, respectively. From the results, 0.05% OS-Ca showed better plant growth and parameters such as plant height, stem diameter (upper and middle part), the number of leaves, and dry weights of each part than the other concentrations of OS-Ca and control. As for stem firmness depending on OS-Ca concentration, the Ca content within stem, maximum firmness, elastic strength, and maximum bending stress of stem in 'Baekma' sprayed with 0.05% OS-Ca showed the highest values among all the treatments and it turned out to be very high level of significance between control and OS-Ca treatments. However, the area and percentage of the inside cavity within horizontal stem section in 'Baekma' did not show any significance between any treatments including control. Thus, stem firmness of 'Baekma' did not show any correlation with the inside cavity area of stem. In conclusion, we recommend foliar sprays with 0.05% OS-Ca at vegetative growth stage to enhance stem firmness of 'Baekma' during transportation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.4
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• pp.229-241
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• 2006

Global air temperature has risen by $0.6^{\circ}C$ over the last one hundred years due to increased atmospheric greenhouse gases. Moreover, this global warming trend is projected to continue in the future. This study was carried out to evaluate spatial variations in rice production areas by simulating rice-growth and development with projected high resolution climate data in Korea far 2011-2100, which was geospatially interpolated from the 25 km gridded data based on the IPCC SRES A2 emission scenario. Satellite remote sensing data were used to pinpoint the rice-growing areas, and corresponding climate data were aggregated to represent the official 'crop reporting county'. For the simulation experiment, we used a CERES-Rice model modified by introducing two equations to calculate the leaf appearance rate based on the effective temperature and existing leaf number and the final number of leaves based on day-length in the photoperiod sensitive phase of rice. We tested the performance of this model using data-sets obtained from transplanting dates and nitrogen fertilization rates experiments over three years (2002 to 2004). The simulation results showed a good performance of this model in heading date prediction [$R^2$=0.9586 for early (Odaebyeo), $R^2$=0.9681 for medium (Hwasungbyeo), and $R^2$=0.9477 for late (Dongjinbyeo) maturity cultivars]. A modified version of CERES-Rice was used to simulate the growth and development of three Japonica varieties, representing early, medium, and late maturity classes, to project crop status for climatological normal years between 2011 and 2100. In order to compare the temporal changes, three sets of data representing 3 climatological years (2011-2040, 2041-2070, and 2071-2100) were successively used to run the model. Simulated growth and yield data of the three Japonica cultivars under the observed climate for 1971-2000 was set as a reference. Compared with the current normal, heading date was accelerated by 7 days for 2011-2040 and 20 days for 2071-2100. Physiological maturity was accelerated by 15 days for 2011-2040 and 30 days for 2071-2100. Rice yield was in general reduced by 6-25%, 3-26%, and 3-25% per 10a in early, medium, and late maturity classes, respectively. However, mid to late maturing varieties showed an increased yield in northern Gyeonggi Province and in most of Kwangwon Province in 2071-2100.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.134-142
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• 2019

This study was conducted to evaluate the growth characteristics of lettuce (Lactuca sativa L.) as affected by artificial light sources and different growing media in a closed-type plant production system (CPPS). The lettuce seeds were sown in the 128-cell plug tray filled with 5 different growing media such as urethane sponge (US), rock-wool (RW), Q-plug (QP), TP-S2 (TP) and PU-7B (PU). The germination rate of lettuce seeds was examined during 12 days after sowing. On the 13 days after sowing, the lettuce seedlings were transplanted in a CPPS with temperature $25{\pm}1^{\circ}C$ and nutrient solution (EC $2.0dS{\cdot}m^{-1}$, pH 6.5) using recirculating deep floating technique system. The light sources were set with FL (fluorescent lamps) and combined RB LEDs (red : blue = 7 : 3) with $150{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and a photoperiod of 14/10 hours (light/dark). The initial germination rate of lettuce was the highest in TP. The final germination and mean daily germination were the significantly highest in RW, QP and TP. The plant height, leaf length, leaf width, leaf area, and fresh and dry weights of shoot were the greatest in QP irradiated with RB LED. The number of leaves, fresh and dry weights of root and SPAD were the greatest in QP and TP irradiated with RB LED. The root length was the longest in TP irradiated with RB LED. Therefore, these results indicate that RB LED was effective for the growth of lettuce and it was also found that the QP and TP were effective for the germination and growth of lettuce in a CPPS. In addition, we confirmed the applicability of the newly developed growing medium TP for the lettuce production in a CPPS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.691-700
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• 2006

Based on the destination IP address of incoming packets, the Internet routers determine next hops and forward packets toward final destinations through If address lookup. The bandwidth of communication links increases exponentially fast as well as the routing table size grows significant as the number of single host networks attached to the Internet increases. Since packets should be processed at wire-speed, the increased link speed reduces the processing time of a packet in routers, and hence more efficient and fast IP address lookup algorithms and architectures are required in the next generation routers. Most of the previous IP lookup schemes compare routing prefixes of shorter length first with a given input IP address. Since IP address lookup needs to find the most specific route of the given input, search continues until the longest matched prefix is found while it keeps remembering the current test matching prefix. In this paper, based on binary search on prefix length, we proposed a new IP address lookup algorithm which compares longer prefixes first. The proposed scheme is consisted of multiple tries with prefixes on leaves only. The trie composed of the longest prefixes is primarily searched whether there is a match with the given input. This processing is repeated for the trio of the next longer prefixes until there finds a match. Hence the proposed algorithm provides the fast search speed. The proposed algorithm also provides the incremental update of prefixes while the previous binary search on length scheme does not provide the incremental update because of pre-processing requirement. In this paper, we performed extensive simulations and showed the performance comparisons with related works.