• Title/Summary/Keyword: Flooding

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The Effect of Soil Flooding on Photosynthesis and Water Relations of Carpinus cordata and Carpinus laxiflora (까치박달과 서어나무의 광합성과 수분관계에 미치는 토양 침수의 영향)

  • 박용목
    • The Korean Journal of Ecology
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    • v.20 no.3
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    • pp.175-179
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    • 1997
  • To explanin allopatric distribution of Carpinus cordata and C. laxiflora in the field the effect of soil flooding on photosynthesis and water relations was tested with field grown saplings. Under the flooding condition stomatal conductance of C. laxiflora decreased markedly from day two after flooding treatment and remanined low throughout the experiment. In contrast, flooding had no effect on stomatal conductance of C. cordata throughout the exper iment. The rate of photosynthesis of C. laxiflora was significantly suppressed under flooding conditions, whereas that of C. cordata was not affected in the flooded condition. On day seven after flooding treatment xylem pressure potential of C. laxiflora significantly decreased. Flooding, however, did not have any effect on the xylem pressure potential of C. cordata throughout the experiment. From these findings it is concluded that there is a difference in resistance to flooding between C. cordata and C. laxiflora and that one of the the factors responsible for allopatric distribution in the two species is flooding.

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Design of Modified Flooding Algorithm Applicable to Sensor Network (센서 네트워크에 적용 가능한 수정된 Flooding 알고리즘 개발)

  • Kim, Sung-Ho;Kim, Si-Hwan
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.1
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    • pp.32-38
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    • 2007
  • Wireless Ad-Hoc network which doesn't utilize any established infrastructure requires different communication protocols. Among them, Flooding algorithm is generally used in wireless Ad-Hoc network for packet transmission. However, Flooding algorithm has many drawbacks such as energy consumption according to the increase of nodes. Therefore, a modified flooding algorithm which can effectively overcome the aforementioned drawbacks is proposed in this paper. The performance of the proposed scheme is shown by various simulation studies.

Rice Bran Application under Deep Flooding can Control Weed and Increase Grain Yield in Organic Rice Culture

  • Yan, Yong-Feng;Fu, Jin-Dong;Lee, Byun-Woo
    • Journal of Crop Science and Biotechnology
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    • v.10 no.2
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    • pp.79-85
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    • 2007
  • Rice bran application just after transplanting has been increasingly practiced as an herbicide-substitute for organic rice production in Korea. However, this practice is frequently reported to be unsatisfactory in weed suppression. An experiment with five treatments that combines flooding depth, rice bran application dose, and herbicide treatment was done in the paddy field to evaluate whether rice bran application under deep flooding can lead to a successful weed control in compensation for the single practice of rice bran application. Rice bran was broadcasted on the flood water surface just after deep flooding of 8 to 10cm that was started at seven days after transplanting. In the shallow flooding plot without herbicide six weed species were recorded: Monochoria vaginalis, Echinochloa crus-galli, Ludvigia prostrate, Cyperus amuricus, Aneima keisak, and Bidens tripartite. Among the first four dominant weed species, deep flooding significantly suppressed the occurrence of Echinochloa crus-galli and Cyperus amuricus while did not suppress the occurrence of Monochoria vaginalis and Ludwigia prostrate. On the contrary, rice bran application under deep flooding suppressed significantly Monochoria vaginalis and Ludwigia prostrate while didn't exert an additional suppression of Echinochloa crus-galli and Cyperus amuricus compared to deep flooding alone. Rice bran application and deep flooding suppressed complimentarily all the six weed species to a satisfactory extent except for Monochoria vaginalis of which suppression efficacy was 31.9%. Deep flooding reduced the panicle number substantially by inhibiting the tiller production, increased the spikelet number per panicle slightly, and leaded to a lower rice grain yield compared to shallow flooding with herbicide. Rice bran application under deep flooding mitigated the panicle reduction due to deep flooding, increased the spikelets per panicle significantly, and thus produced even higher grain yield in the rice bran application of 2000kg $ha^{-1}$ as compared to the shallow flooding treatment with herbicide. In conclusion, this practice applying rice bran under deep flooding would be promising to be incorporated as an integral practice for an organic rice farming system.

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FLOODING PSA BY CONSIDERING THE OPERATING EXPERIENCE DATA OF KOREAN PWRs

  • Choi, Sun-Yeong;Yang, Joon-Eon
    • Nuclear Engineering and Technology
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    • v.39 no.3
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    • pp.215-220
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    • 2007
  • The existing flooding Probabilistic Safety Analysis(PSA) was updated to reflect the Korean plant specific operating experience data into the flooding frequency to improve the PSA quality. Both the Nuclear Power Experience(NPE) database and the Korea Nuclear Pipe Failure Database(NuPIPE) databases were used in this study, and from these databases, only the Pressurized Water Reactor(PWR) data were used for the flooding frequencies of the flooding areas in the primary auxiliary building. With these databases and a Bayesian method, the flooding frequencies for the flooding areas were estimated. Subsequently, the Core Damage Frequency(CDF) for the flooding PSA of the Ulchin(UCN) unit 3 and 4 plants based on the Korean Standard Nuclear Power Plant(KSNP) internal full-power PSA model was recalculated. The evaluation results showed that sixteen flooding events are potentially significant according to the screening criterion, while there were two flooding events exceeding the screening criterion of the existing UCN 3 and 4 flooding PSA. The result was compared with two kinds of cases: (1) the flooding frequency and CDF from the method of the existing flooding PSA with the PWR and Boiled Water Reactor(BWR) data of the NPE database and the Maximum Likelihood Estimate(MLE) method and (2) the flooding frequency and CDF with the NPE database(PWR and BWR data), NuPIPE database, and a Bayesian method. From the comparison, a difference in CDF results was revealed more clearly between the CDF from this study and case (2) than between case (1) and case (2). That is, the number of flooding events exceeding the screen criterion further increased when only the PWR data were used for the primary auxiliary building than when the Korean specific data were used.

Flooding Tolerance of Cool-Season Turfgrass for the Revegetation of Waterside Slopes (수변 비탈면 녹화를 위한 한지형잔디의 내침수성 연구)

  • Shim, Sang-Ryul
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.18 no.2
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    • pp.45-52
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    • 2015
  • Cool-season turfgrass is a rapidly increasing of usage for the revegetation of waterside slopes in dams, lakes and rivers. The purpose of this research is to identify the flooding tolerance of cool-season turfgrass with respect to the flooding periods of 0(control), 2, 4 and 6 days, respectively. The surface coverage ratio, turfgrass injury and soil moisture content were measured to assess the flooding tolerance of cool-season turfgrass. The increase in the flooding periods with 4 and 6 days resulted in the lower surface coverage ratio for cool-season turfgrass while no significant difference was found in the 2 days flooding when compared to 0 day (the control plot) flooding plot. In case of the turfgrass injury and the soil moisture content, however, the higher values were found with the increase of flooding periods in 2, 4 to 6 days. We observed that the higher the turfgrass injury and soil moisture content increased, the lower the surface covrage ratio decreased. In these regards, we also observed that the tolerance of cool season turfgrass were high in the 2 days flooding condition, medium in the 4 days flooding condition and low in the 6 days flooding condition. The flooding tolerance of cool-season turfgrass was gradually weakened in over 2 days flooding periods due to $O_2$ deficiency in the anaerobic soil condition. Therefore, we could suggest cool-season turfgrass within 2 days flooding periods for the revegetation of waterside slopes in dams, lakes and rivers.

Design and Implementation of ATP(Advanced Persistent Threat) Attack Tool Using HTTP Get Flooding Technology (HTTP Get Flooding 기술을 이용한 APT(지능적 지속 위협)공격 도구의 설계와 구현)

  • Cheon, Woo-Bong;Park, Won-Hyung;Chung, Tai-Myoung
    • The Journal of Korean Association of Computer Education
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    • v.14 no.6
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    • pp.65-73
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    • 2011
  • As we can see from the recent cyber attack, APT(Advanced Persistent Threat) is trend of hacking attack in the World. Thus, HTTP Get Flooding attack is considered to be one of the most successful attacks in cyber attack method. In this paper, designs and implements new technique for the cyber attack using HTTP get flooding technology. also, I need a defence about DDoS attack through APT Tools.

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Effect of Overhead Flooding Stress on Protein Profiles, Fatty Acid Composition, and Lipid Peroxidation in Rice (벼의 관수기간 및 수질이 단백질, 지방산조성 및 지질과산화에 미치는 영향)

  • 이상각;이병모;강병화
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.3
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    • pp.215-220
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    • 2001
  • Biochemical responses of rice to the flooding stress with different water turbidities and flooding time were evaluated. About 20% decrease of soluble protein was occurred with flooding stress. The decreasing rate was higher as flooding time and higher turbidity increased. Especially, dramatic decrease of soluble protein content was observed after 36 hrs of flooding. No protein subunit change was found before and after flooding. However, subunit product of 53 Kd increased from the beginning of flooding and subunit of 28 Kd was increased 48 hrs and 54 hrs after flooding. Lipid peroxidation increased about 150% by flooding. There was no significant difference in lipid peroxidation between clear and sub-muddy water, However, the lipid peroxidation was increased up to 180% at 60hrs of flooding. The malondialdehyde content (MDA) was higher in muddy water at the beginning of flooding and increased about 190-200% 36 hrs after flooding. Catalase activity increased with increasing turbidity and flooding time. Forty eight hours of flooding time provided a criteria for dramatic increase of catalase activity. In general, increase of saturated fatty acids and decrease of unsaturated fatty acids occurred with flooding treatment. Among unsaturated fatty acids, monounsaturated increased and polyunsaturated decreased. Double bond index(DBI) decreased as flooding time was extended and turbidity increased.

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Effect of Overhead Flooding Stress on Photosynthesis and Growth in Rice (벼의 관수기간 및 수질이 광합성과 생육에 미치는 영향)

  • 이상각;강병화
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.3
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    • pp.209-214
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    • 2001
  • Physiological responses of rice to the flooding time of different water turbidity (clear water, sub-muddy water, muddy water) were analyzed as photosynthesis, chlorophyll fluorescence, transpiration, and physiological recovery. Photosynthetic rate was higher as turbidity increased and decreased as flooding time was extended. Floodings of 36 hrs and 42 hrs were resulted in 25% and 50% decrease of photosynthetic rate, respectively. Transpiration rate was higher in high turbidity (increased 30%, 25%, and 20% in clear, sub-muddy, and muddy water, respectively) and in increased floodings. Fv/Fm decreased as increased turbidity and flooding time. About 20% decrease of Fv/Fm was recorded in 48 hrs and 36 hrs after flooding with clear water and sub-muddy water(including muddy water), respectively. Total nitrogen was decreased with flooding treatment. Significant decrease of total nitrogen was occurred 36 hrs after flooding with muddy water, Dry weight measured 2 weeks after flooding treatment as an indication of recovery of flooding stress didn't show significant difference with turbidity, but significantly decreased as flooding time was prolonged. About 25% and 50% decreases were found in 24 hrs and 42 hrs flooding time, respectively. furthermore, 48 hrs of flooding with sub-muddy and muddy water resulted in no physiological recovery. Photosynthetic rate was decreased 15% and 10% with clear water and muddy water(including sub-muddy water), respectively. The rate was dramatically decreased 42 hrs after flooding. Transpiration rate increased about 20% regardless of turbidity and flooding time. We found transitory decrease of photosynthetic and transpiration rate at the point of 24 hrs after flooding and right after do-flooding.

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Comparisons in Anatomical Morphology Between Soybean Cultivars of Different Flooding Tolerance under Early Vegetative Flooding Conditions (영양생장기 습해 처리에 따른 콩 품종의 해부형태학적 특성 비교)

  • Lee, Choong-Yeul;Cho, Jin-Woong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.52 no.3
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    • pp.320-324
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    • 2007
  • To characterize flooding-affected anatomical morphology changes in soybean, flooding-tolerant cv Pung-sannamulkong (PSNK) and flooding-sensitive cv. Sobaek-namulkong (SBNK) at 5 trifoliate leaf stage were exposed to flooding by maintaining tap water 2 cm above soil surface for 9 days and resultant microscopic anatomical changes in leaf and hypocotyl cross-sections along with chlorophyll content and photosynthetic rate changes were compared. Flooding-sensitive SBNK exhibited more significant decrement in chlorophyll content, photosynthetic rate, number of palisade parenchyma, and leaf dry matter compared to cv. PSNK. Flooding decreased fineness of palisade parenchyma, while inducing wider xylem vessel, especially in PSNK. The aerenchyma formation in hypocotyls under flooding could be observed only in flooding-resistant PSNK. All these anatomical changes seems to be related with higher physiolocial activity and resultant resistance against flooding in PSNK compared to flood-sensitive PSNK.

Estimation Process for the Capacity of Emergency Drainage System on a Ship after Flooding Accident (선박 침수사고를 대비한 비상용 배수시스템 용량추정 프로세스에 관한 연구)

  • PARK, Byung-Soo;KIM, Sung-Soo;LEE, Soon-Sup;KANG, Dong-Hoon;CHO, Hyun-Kuk
    • Journal of Fisheries and Marine Sciences Education
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    • v.28 no.6
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    • pp.1739-1750
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    • 2016
  • This paper proposed a process for estimating the required capacity of emergency drainage system on a ship when the ship encounters a flooding accident. The process was established by selecting target vessel, making a scenario of flooding accident, considering static behavior of flooding water and the effect of ship motion due to ocean condition. In order to obtain the object of the research, MATLAB codes were developed for analyzing of static behavior of flooding water. Additionally, Ansys AQWA-NAUT was used to analyze the motion of the ship under an ocean condition and then the effect of ship motion was considered when the static behavior of flooding water was studied. The research exploited a trawler as a target vessel, and estimate the necessary capacity of the trawler's emergency drainage system by simulating a flooding water in the vessel.