• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.57-57
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• 2022

In many areas of the world, salt damage and drought have had a negative impact on human survival due to a decrease in agricultural productivity. For instance, about 50% of agricultural land will be affected by salt damage by 2050. Biostimulants such as plant extracts can not only increase the nutrient utilization efficiency of plants, but also promote plant growth and increase resistance to abiotic or biotic stress. Therefore, the objective of this study was to determine how selected plant extracts might reduce levels of stress caused by drought and salt and to better understand the physiological response mechanisms of rice plants. In this study, we used Soybean leaves, Soybean stems and Allium tuberosum, Allium cepa, Hizikia fusiforme, and Gracilaria verrucosa extracts were used. These extracts had been used in previous studies and were found to be effective. The materials were dried in a dry oven at 50℃ for 5 days and ground using a blender. Each 50 g of materials was put in 1 L of distilled water, stirred for 24 hours, filtered using 4 layers of mirocloth, and then concentrated using a concentrator. Rice (cv. Hopumbyeo) seeds were immersed and germinated, and then sown in seedbeds filled with commercial soil. In drought experiments, three rice seedlings at 1 week after seeding was transplanted into 100 ml cups filled with commercial soils and grown until the 4-leaf stage. For this experiment, the soil weight in a cup was equalized, and water was allowed to become 100% saturated and then drained for 24 hours. Thereafter, plant extracts at 3% concentrations were applied to the soils. For NaCl treatments, rice plants at 17 days after seeding were treated with either 100 mM NaCl or plant extracts at 1%+ 100 mM NaCl combinations in the growth chamber. Leaf injury, relative water content, photosynthetic efficiency, and chlorophyll contents were measured at 3, 5, and 6 days after treatments. Shoot fresh weight of rice under drought conditions increased 28-37% in response to treatments of Soybean leaf, Soybean stem, Allium tuberosum, Allium cepa, Hizikia fusiforme, and Gracilaria verrucosa extracts at 3% when compared with control plants. Shoot fresh weight of rice subjected to 100 mM NaCl treatments also increased by 6-24% in response to Soybean leaf, Soybean stem, Allium tuberosum, Allium cepa, Hizikia fusiforme, and Gracilaria verrucosa extracts at 3% when compared with control plants. Compared to the control, rice plants treated with these six extracts and subjected to drought conditions had significantly higher relative water content, Fv/Fm, total chlorophyll and total carotenoids than control plants. With the exception of relative water contents, rice plants treated with the six extracts and subjected to salt stress (100 mM NaCl treatments) had significantly higher Fv/Fm, total chlorophyll and total carotenoids than control plants. However, the type of extract used did not produce significant difference in these parameters. Thus, all the plant extracts used in this study could mitigate drought and NaCl stresses and could also contribute substantially to sustainable crop production.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.117-122
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• 2003

Every year in domestic slope failure caused by rainfall is happening frequently. Specially, causable failure accident by localized downpour accompanied when summer rainy season period and produces typhoon gets damage of large scale human life and property. Failure happened at slope of 121 places ranged whole country national highway by No.15 typhoon Rusa that strike whole country during 3 days from August 30, 2002. Slope failure that happen by typhoon are judged for major cause to effect of ground saturation and surface water by localized downpour. In this research, failure characteristic was analyzed to target 20 places attaining site investigation among failure slope. As a result, erosions by surface water was construed for major cause of failure and judged for direct relation in failure slope weathering and topography Also, result that analyze inclination of failure part, in the case of ripping rock, inclination of failure side is forming Incline of the lowest 40$^{\circ}$, because surface failure of depth 4m on or so scale happened, it is require that regulating plan gently design standard inclination of weathered rock and soil layer And it is considered that desirable preparation of design standard about measure that help smooth drainage of surface water and can restrain percolation in ground to reduce failure damage by rainfall.

• Corrosion Science and Technology
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• v.18 no.6
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• pp.277-284
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• 2019

External corrosion control of buried pipe can be achieved by the combination of barrier coating and cathodic protection. Coating damage and deterioration can be induced by many reasons; damage during handling and laying, enhanced failure at low temperatures, failure during commissioning and operation, disbanding due to inadequate surface cleaning, rock penetration during installation and service etc. This work focused on the effect of survey conditions on the reliability of coating flaw detection of buried pipes. The effects of applied voltage and anode location on the detection reliability of coating flaw of buried pipe in soil with the resistivity of ca. 25.8 kΩ·cm were discussed. Higher applied voltage increased the detection reliability, regardless of buried depth, but deeper burial depth reduced the reliability. The location of the anode has influenced on the detection reliability. This behaviour may be induced by the variation of current distribution by the applied voltage and buried depth. From the relationship between the applied voltage and reliability, the needed detection potential to get a desire detection reliability can be calculated to get 100% detection reliability using the derived equation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.3
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• pp.309-317
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• 2016

Debris flows are rapidly flowing masses of water mixed with soil and gravel from landslides which are caused by typhoons or rainstorms. The combination of Korea’s mountain dominated topography (70%) and seasonal heavy rains and typhoons causes landslides and large-scale debris flows from June to August. These phenomena often cause property damage and casualties that amount up to 20% of total annual disaster fatalities. The key point to predicting debris flow is to understand its movement mechanism, erosion, and deposition. In order to achieve a more accurate estimation of debris flow path and damage, this study incorporates quantitative analysis of high resolution LiDAR DEM (GSD 10cm) to delineate geomorphic and topographic changes induced by Jinbu real scale debris flow test.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.225-229
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• 2003

Plant ash and soil drainage, derived by frequent mountain fires during winter, might cause biological contamination to seaweeds at seashore and river mouse area. To thalli of Ulva pertusa, maximum non-lethal concentration(MNLC), lethal concentration 50 $(LC_{50})$ and minimum lethal concentration (MLC) of pine needle ash were shown as 60, 350 and 550 mg/mL, respectively. The yellow loess and granite sand did not damage at concentrations of 20 and 200 mg/mL, respectively To thalli of Porphyra yezoensis, the MNLC, LC5O, MLC of pine needle ash were shown as 0.08, 0.4 and 1.0 mg/mL, respectively. Effects of yellow loess and granite sand were approximately 1/2 and 1/10 of the ash. To thalli of Undaria pinnatifida, the pine needle ash, yellow loess and granite sand did not damage at the concentration range of 20 to 40 mg/mL. Change of pigments $(chlorophyll\;\alpha,\;lutein,\;\beta-carotene,\;phycoerthrin)$ was also determined at the MNLC, $LC-{50}$ and MLC of pine needle ash. Among three seaweeds tested, P. yezoensis produced the most 2.7-fold of lutein and 2.3-fold of $\beta-carotene$ at $LC-{50}$ of the ash. Thus the P. yezoensis, appeared as a sensitive indicator, could be used as one of test organisms for determination of the biological effect of pollutants contaminated in marine environment.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1397-1404
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• 2014

Grab cranes are used for multi-purpose when the sand and soil are deposited into harbor wharf or the undersea construction is performed. Among the components of crane grab, the wire drum and disc brake pad are key expendables and have disadvantages that lot of heat is generated and very expensive when replacing them. In this study, the thermal image analysis for the disc brake, which works with wire drum of the crane is suggested. The suggested system performs the pad thermal diagnosis through the thermal image using the characteristics that the disc and pad surface temperatures are distributed abnormally before the brake failure and the disc pad damage. Therefore, the damage by the failure can be prevented by discovering the abnormality of the machine parts before failure and the life cycle of the pad and the cost can be extended and saved by operating the crane performing constant checkup for the overload.

• Earthquakes and Structures
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• v.7 no.4
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• pp.485-510
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• 2014

In performance-based seismic design procedures Peak Ground Acceleration (PGA) and pseudo-Spectral acceleration ($S_a$) are commonly used to predict the response of structures to earthquake. Recently, research has been carried out to evaluate the predictive capability of these standard Intensity Measures (IMs) with respect to different types of structures and Engineering Demand Parameter (EDP) commonly used to measure damage. Efforts have been also spent to propose alternative IMs that are able to improve the results of the response predictions. However, most of these IMs are not usually employed in probabilistic seismic demand analyses because of the lack of reliable Ground Motion Prediction Equations (GMPEs). In order to define seismic hazard and thus to calculate demand hazard curves it is essential, in fact, to establish a GMPE for the earthquake intensity. In the light of this need, new GMPEs are proposed here for the elastic input energy spectra, energy-based intensity measures that have been shown to be good predictors of both structural and non-structural damage for many types of structures. The proposed GMPEs are developed using mixed-effects models by empirical regressions on a large number of strong-motions selected from the NGA database. Parametric analyses are carried out to show the effect of some properties variation, such as fault mechanism, type of soil, earthquake magnitude and distance, on the considered IMs. Results of comparisons between the proposed GMPEs and other from the literature are finally shown.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.236-236
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• 2017

Low soil pH causes from $H^+$ rhizotoxicity results in nutrients unavailability in the growing media, inhibits plant growth, development and reduces crop yields. The present study was carried out to reveal morpholophysiological and biochemical responses of wheat (Triticum aestivum L.) to acidity stress. Four wheat varieties viz. BARI Wheat-21, BARI Wheat-25, BARI Wheat-26 and BARI Wheat-30 were used in the study. Eight-day-old seedlings were exposed to different pH levels (3.5, 4.5, 5.5 and 6.5) of growing media. Acidity stress at any level reduced biomass, water, and chlorophyll contents in all the varieties; whereas BARI Wheat-26 showed the least damage. $H^+$ rhizotoxicity also caused oxidative stress through excess production of reactive oxygen species and methylglyoxal which increase lipid peroxidation in all the varieties but the lowest oxidative damage was observed in BARI Wheat-26 due to better performance of the antioxidant defense and glyoxalase systems. Considering the growth, physiological and biochemical attributes BARI Wheat-26 may be considered as acidity stress tolerant, among the variety examined.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.508-522
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• 2019

Because of the slope failure, not only property damage but also human damage can occur, slope stability analysis should be conducted to predict and reinforce of the slope. This paper, defines the ground areas that can be characterized in terms of slope failure such as Rockmass jointset, Rockmass fault, Soil, Leakage water and Crush zone in sloped images. As a result, it was shown that the deep learning instance segmentation network can be used to recognize and automatically segment the precise shape of the ground region with different characteristics shown in the image. It showed the possibility of supporting the slope mapping work and automatically calculating the ground characteristics information of slopes necessary for decision making such as slope reinforcement.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.607-618
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• 2012

The blueberry gall midge, Dasineura oxycoccana (Diptera: Cecidomyiidae), has known as a key pest of blueberries in the southeastern United States, Europe and Canada. It can cause considerable damage to developing flower buds and also injure vegetative growth by distorting and blackening shoot tips on blueberries. In 2010, same damage symptoms were observed on blueberries, Vaccinium spp., in Hwaseong-si, Gyeonggi-do. And, D. oxycoccana was identified from the farms and it was designated as a quarantine pest in Korea. The occurrences of D. oxycoccana and its damages were investigated in the blueberry greenhouse in 2011. Nationwide survey revealed that most of the blueberry greenhouses were infected by D. oxycoccana. An environment-friendly management method for D. oxycoccana was developed by changing soil environment in the blueberry greenhouse.