• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.4
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• pp.1-14
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• 2019

The 1st Forest Health Management survey was conducted to examine the health of the forests in Korea. However, in order to understand the health of the forests, which account for 63.7% of the total land area in South Korea, it is necessary to comprehensively spatialize the results of the survey beyond the sampling points. In this regard, out of the sample points of the 1st Forest Health Management survey in Gyeongbuk area, 78 spots were selected. For these spots, the species diversity index was selected from the survey sections, and the spatial interpolation method was applied. Inverse distance weighted (IDW), Ordinary Kriging and Ordinary Cokriging were applied as spatial interpolation methods. Ordinary Cokriging was performed by selecting vegetation indices which are highly correlated with species diversity index as a secondary variable. The vegetation indices - Normalized Differential Vegetation Index(NDVI), Leaf Area Index(LAI), Sample Ratio(SR) and Soil Adjusted Vegetation Index(SAVI) - were extracted from Landsat 8 OLI. Verification was performed by the spatial interpolation method with Mean Error(ME) and Root Mean Square Error(RMSE). As a result, Ordinary Cokriging using SR showed the most accurate result with ME value of 0.0000218 and RMSE value of 0.63983. Ordinary Cokriging using SR was proven to be more accurate than Ordinary Kriging, IDW, using one variable. This indicates that the spatial interpolation method using the vegetation indices is more suitable for spatialization of the biodiversity index sample points of 1st Forest Health Management survey.

• The Journal of Natural Sciences
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• v.5 no.2
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• pp.49-62
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• 1992

This study was carried out to investigate the emergence, growth and yield components in rice inassoccation with Several cultivation methods direct sowing flooded paddy field(DSF), direct sowing by airplane(DSA), direct sowing in dry paddy field(DSD), 8days seedling planting(8DS), and 35days seedlingplanting(35DS). Also this study was attempeted to know the effects of calcium peroxide on germinationand early growth of rice under different soil conditions, seeding depth, application of organic matter,indirect sowing flooded paddy field.1. Rate of emergence was 73% in DSF, 70% in DSA, 62% in DSD, respectively, under the different cultivation method of rice in reclaimed paddy field.2. Degree of lodging in relation to cultivation was 5 at both DSF and DSA, 3 at DSD, 2 at both 8DS and 35DS respectively.3. Maximum tiller number was 568 per m2 at DSF and 527 at DSA. Heating was delayed for 4 days at DSF, 8 days at DSD and 2 days at 8DS as comparison with that at 35DS.4. Yield was higher 1% to 3% at DSF than that at DSA and DSD while decreased by 12% as compared with that of seedling planting.5. Total dry weight of seedling was decreased by 57% at 8DS, 60% at DSF 63% at DSD, respectively, under 0.3% of salinity. Ratio of decreasing in dry weight was higher with high salinity.6. The amount of O2 released was recorded highest to 2 to 3days after irrigatition, thereafter remaining constant to 10 days after irrigatition.7. The optimum coating amount of calcium peroxide for germination was a half of rice seed weight with 1 cm sowing depth and one-fold with 2-cm sowing depth when rice straw was not applied. With rice straw applied, on the other hand, the amount of peroxide was one-fold with 1-cm sowing depth. It was found that, under the condition of applied 600kg/10a, of 2-cm soil depth with rice straw calcium peroxide coating had no effect on emergence of rice seedling.8. In reclaimed paddy field, lodging degree was 7 with direct sowing by machine and 9 with direct sowing by hand.9. Yield was increased by 5% by applying rice straw with direct sowing by machine.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.1
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• pp.47-53
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• 2011

The artificial aggregates (AAs) were manufactured from the parent batch powders consisting of bottom ash containing excess unburned carbon and dredged soil, 7 : 3 weight ratio by direct sintering method and those physical properties were evaluated. Especially, the effects of waste glass or frit (NWG) which was made by addition of 5 wt% $Na_2O$ to the waste glass upon the bloating phenomenon of AAs were analyzed. The AAs manufactured from the parent batch powders showed a lower specific gravity than that of specimens containing waste glass or NWG due to excess u$Na_2O$nburned carbon which usually obstructs a sintering process. But, the waste glass added on parent batch powders promoted the sintering and densification thus increased the specific gravity of AAs. Also the specific gravity of AAs added with 5 wt% NWG, was lowered compared to that of AAs added with as-received waste glass. This is because of bloating of shell which captures gases owing to the lowered viscosity of liquid formed at the specimen surface caused by $Na_2O$ addition. In conclusion, the AAs sintered at above $1100^{\circ}C$ in this study showed characters of lightweight aggregate of specific gravity 1.15~1.34 and water absorption 11~19 %, and the bloating phenomenon of AAs was occurred at the shell rather black core part.

• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.75-84
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• 2009

This study was carried out to determine the effect of swine liquid manure on the rice growth and yield in 2006. Field experiment was conducted under variable application rates; 100%, 120%, 150%, 180% N level of slurry based on 11 kg N 10a recommended amount of nitrogen. The experimental sites were located at Cheorwon in Gangwondo area. The results were summerized as follows; In the plot treated with swine liquid manure of 150% and 180% N levels, the plant height and tillers were higher, and the color of leaf was darker than that of 100% N level of swine liquid manure. Rice yield in the plot applied with 120% N slurry level was increased at 11%, but those of 150%, 180% N-level application plots were reduced 10, 19% compared to 100% N level, respectively. Rice quality of the 100 and 120% application plots of swine liquid manure was significantly better than those of 150 and 180% levels of application plots. Total nitrogen content in rice plant after harvesting was increased with increasing levels of swine liquid manure. The content of K in the soil was accumulated in plot treated with 150%, 180% slurry compared to control plot. The heavy metal contents in soils were not increased treated with swine liquid manure. The density of bacteria was low in the application plot of 180%N of liquid swine manure. The bacteria/fungi ratio was highest in 120% N level of liquid manure treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.116-123
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• 2004

This study was conducted to investigate the changes in physicochemical and microbiological properties during fermenting process of organic fertilizer which was made from the mixture of organic materials such as sesame oil cake, fish meal, blood meal, rice bran, ground bone meal, and natural minerals such as illite, crusted oyster shell and loess. They were mixed and fermented for 70 days. The sesame oil cake and rice bran, major ingredients for organic fertilizers, consisted of 7.6 and 2.6% total nitrogen, 3.6 and 4.6% $P_2O_5$, 1.4 and 2.2% $K_2O$, respectively. The ground bone meal included 29.2% $P_2O_5$ and illite included 3.8% $K_2O$. Temperature of organic fertilizer during the fermentation rapidly increased over $50^{\circ}C$ within 2 days after mixing and stabilized similar to outdoor temperature after 40 days. Moisture content decreased from 36.3 to 16.0% after 1 month. C/N ratio of organic fertilizer slightly increased until 30 days and thereafter, it slowly decreased, It resulted from the faster decrease of total nitrogen concentration compared with organic matter. Concentration of $NH_4-N$ in organic fertilizer rapidly increased from 1,504 to $5,530mg\;kg^{-1}$, the highest concentration after 10 days. Meantime, $NO_3-N$ concentration was low and constant about $150mg\;kg^{-1}$ over the whole fermenting period. This result seemed to be due to the high pH. The organic ferfilizer fermented for 70 days was composed of 2.7% N, 2.8% $P_2O_5$, 1.8% $K_2O$, and 35.9% organic matter. Total populations of aerobic bacteria, Bacillus sp. and actinomycetes, after fermenting process, were $12.5{\times}10^{10}$, $45.5{\times}10^{5}$ and $13.6{\times}10^{5}cfu\;g^{-1}$ respectively. Pseudomonas sp. was $71.9{\times}10^{7}cfu\;g^{-1}$ at first, but it rapidly decreased according to the rise of temperature. Yeasts played an important role in the early stage of fermentation and molds did in the late stage.

• Korean Journal of Remote Sensing
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• v.38 no.6_2
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• pp.1723-1735
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• 2022

Landslides are one of the most prevalent natural disasters, threating both humans and property. Also landslides can cause damage at the national level, so effective prediction and prevention are essential. Research to produce a landslide susceptibility map with high accuracy is steadily being conducted, and various models have been applied to landslide susceptibility analysis. Pixel-based machine learning models such as frequency ratio models, logistic regression models, ensembles models, and Artificial Neural Networks have been mainly applied. Recent studies have shown that the kernel-based convolutional neural network (CNN) technique is effective and that the spatial characteristics of input data have a significant effect on the accuracy of landslide susceptibility mapping. For this reason, the purpose of this study is to analyze landslide vulnerability using a pixel-based deep neural network model and a patch-based convolutional neural network model. The research area was set up in Gangwon-do, including Inje, Gangneung, and Pyeongchang, where landslides occurred frequently and damaged. Landslide-related factors include slope, curvature, stream power index (SPI), topographic wetness index (TWI), topographic position index (TPI), timber diameter, timber age, lithology, land use, soil depth, soil parent material, lineament density, fault density, normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) were used. Landslide-related factors were built into a spatial database through data preprocessing, and landslide susceptibility map was predicted using deep neural network (DNN) and CNN models. The model and landslide susceptibility map were verified through average precision (AP) and root mean square errors (RMSE), and as a result of the verification, the patch-based CNN model showed 3.4% improved performance compared to the pixel-based DNN model. The results of this study can be used to predict landslides and are expected to serve as a scientific basis for establishing land use policies and landslide management policies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.2
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• pp.11-18
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• 1985

A row of bored piles has been used in several excavation works to retain the earth. This excavation bracing system has much effect on low-vibration and low-noise during construction. The system is also effective to provide protection to the adjacent existing ground and structures. For the purpose of establishment of a logical design method for the bored piles, first, a theoretical equation to estimate the resistance of piles is derived. Because arching action of soils between piles is considered in the equation, the characteristics of soils and the installation condition of piles would be considered logically from the beginning. Then a method is investigated to decide the interval ratio of piles. According to the method, the interval between piles can be decided from the information of the Peck's stability number, the coefficient of lateral earth pressure and the internal friction angle of soil. Finally, a design method is presented for the bored piles used for excavation work. In the presented design method, such factors as depth of excavation, pile diameter, interval between piles, pile length below bottom of excavation and pile stiffness, can be selected systematically.

• Korean Journal of Organic Agriculture
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• v.16 no.3
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• pp.287-298
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• 2008

This experiment was carried out to investigate the effect of different feed conditions on growth, cast production and conversion efficiency of organic matter to the earthworm. The experiment was tested on cow manure(CM) mixed with rice hulls (RH) or rice straw(RS). The mixture ratios were designed as one time, two times and three times of cow manure volume, respectively. The CM and RH mixtures resulted better on growth rate, reproductive efficiency and wormcast production than those for CM and RS mixtures. Especially on three times of RH mixture showed the highest growth characteristics compared to the other mixtures. Although both were between 20 and 34 on carbon and nitrogen ratio, the result inferred that the difference on the growth might have been caused by feeding conditions. On the mixtures of cow manure with rice hulls(CM+RH) was significantly higher on values on the conversion rate and conversion efficiency of organic matter to earthworm tissues than the mixtures of cow manure with rice straw(CM+RS). The most concerned point of the mixture of earthworm feed is that high contents of volatile solid and total carbon that increases in conversion efficiency of organic matter to earthworm tissues, and also causes the increase in growth rate and reproductive efficiency. The wormcast could be used as a valuable plant growth medium or soil conditioner for sustainable agriculture and it may be due to their high qualities of physico-chemical properties.

• Journal of the Korean Geotechnical Society
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• v.37 no.11
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• pp.71-81
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• 2021

The purpose of this study is liquefaction phenomenon was simulated using the 1g shaking table test. Analysis of liquefaction and Re-liquefaction behavior according to the ground conditions was analyzed when an embankment exists above the ground. The soil used in the experiment was silica sand and the ground composition was a liquefied layer of 50cm (Case 1), a non-liquefied layer of 17.5cm and a liquefied layer of 32.5cm (Case 2). The embankment was formed by fixing the height of 10cm and the slope of the slope at a ratio of 1:1.8. For seismic waves, excitation of a 5Hz sine wave was performed for 8 seconds, and a total of 5 case excitations were performed. In Case 1, it was confirmed that liquefaction occurred at all depths during the first vibration excitation at the free-field and that liquefaction did not occur at all depths except 5cm at the third vibration excitation. At the center of the embankment, liquefaction occurred up to a depth of 20cm during the first vibration excitation, and it was confirmed that liquefaction did not occur at all depths except for a depth of 5cm during the second vibration excitation.

• Journal of Plant Biotechnology
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• v.46 no.2
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• pp.119-126
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• 2019

This study was conducted to investigate the optimal culture method for gametophyte and sporophyte propagation in Coniogramme japonica (Thunb.) Diels, which can be used in various fields. The propagation of prothallus were cultured in 1/4 - 1 Murashige and Skoog medium and Knop medium for 10 weeks. The results indicated that the fresh weight of prothallus was the highest (14.5 g) in 1MS medium. Subsequently, various concentrations of sucrose, activated charcoal and nitrogen source were also added to 1MS medium and cultured for 8 weeks. The results provided that the sucrose concentration was 3% and the fresh weight of prothallus was the highest 10.8 g. According to the concentration in the range of 8.8 ~ 10.8 g, in the case of activated charcoal, the four treatments showed no significant difference. The nitrogen source was added at a concentration of 30, 60 and 120 mM with the ratio of ${NH_4}^+:{NO_3}^-$ being 1 : 2. As a result, the fresh weight of all treatments increased to similar level but there was no significant difference. We investigated sporophyte formation according to soil type and the highest number of sporophytes at 228.0 was formed in soils mixed with horticultural substrate and decomposed granite at 2 : 1 (v : v). On the other hand, sporophyte was not formed in soils containing peatmoss except for the one with peatmoss and decomposed granite at 2 : 1 (v : v).