• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.330-334
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• 2001

1. The purpose of this study is to evaluate the hydrologic impact due to temporal land cover changes of Gyueongan-cheon watershed. 2. WMS(Watershed Modeling System) HEC-1 was adopted and the required data such as DEM(Digital Elevation Model), stream network, soil map were prepared, and land cover map was made by using Landsat TM data. 3. Due to the increase of urban area and paddy field, the runoff ratio increased 5.8% during the past decade.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3778-3793
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• 2019

Image steganography is one of the key types of steganography where a message to be sent is hidden inside the cover image. The most commonly used techniques for image steganography rely on LSB steganography. In this paper, a novel image steganography technique based on blocks matrix determinant method is proposed. Under this method, a cover image is divided into blocks of size $2{\times}2$ pixels and the determinant of each block is calculated. The comparison of the determinant values and corresponding data bits yields a delicate way for the embedment of data bits. The main aim of the proposed technique is to ensure concealment of secret data inside an image without affecting the cover image quality. When the proposed steganography method is compared with other existing LSB steganography methods, it is observed that it not only provides higher PSNR, lower MSE but also guarantees better quality of the stego image.

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.314-323
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• 2001

This study aimed to clarify the influencing factors of mesopore ratio on a pore geometry of surface soil in coniferous stands as an index of the water retention capacity. Twenty three factors including site conditions and soil properties were analyzed by spss/pc + for the data collected during March to October of 1993. The factors influencing the mesopore ratio(pF2.7) on the surface soil were as follows; macropore ratio(pF1.6), slope, crown-cover rates, thickness of F layer, organic matter contents, and the growing stock. And influencing factor on the ratio of mesopore in the soil surface was correlated with percentage of amount of clay, soil surface, A and B horizon soil hardness shows high negative significance. Also, multiple regression equations for mesopore ratios of surface soil and surface soil hardness, clear length, growing stock, B horizon of soil hardness, organic matter contents show high significance($R^2$; 0.80). In coniferous stands, it is effective in promoting development on the ratio of mesopore that forest practice for enhancing of the water resource retention capacity should be carried out when the crown-cover rates of stands are more than 80 percentages.

• Journal of Korean Society of Rural Planning
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• v.16 no.4
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• pp.53-60
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• 2010

This study aims at suggesting the attributes and limitations of each methods through the evaluation of the verified analysis results, so that it will be possible to select an efficient method that may be applied to assess the green coverage ratio. Green coverage areas of each sites subject to this study were assessed utilizing the following four methods. First, assessment of green coverage area through direct planimetry of satellite images. Second, assessment of green coverage area using land cover map. Third, assessment of green coverage area utilizing the band value in satellite images. Forth, assessment of green coverage area using and land cover map and reference materials. For this study, four urban zones of the City of Seosan in Chungcheongnam-do. As a result, this study show that the best calculation method is the one that combines the merits of first and second methods. This method is expected to be suitable for application in research sites of middle size and above. It is also deemed that it will be possible to apply this method in researches of wide area, such as setting up master plans for parks and green zones established by each local self-government organizations.

• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.19-24
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• 2003

The self-attenuation factor for an $^{198}Au$ sample and the 0.412 MeV gamma-ray penetration ratio in the circular Al-cover of the radiation detector have been determined using an analytical solution and MCNP code. The results show that the self-attenuation factors obtained from the analytical solution coincide with those of MCNP code for all but the Au sample with the relatively larger radius. Then the maximum difference between the two methods appears to be 9 % in the Au sample of 1.5 mm radius. It also is revealed that the analytical solutions of the 0.412 MeV gamma-ray penetration ratio in the Al-cover of 7.62 cm radius are consistent with those of the MCNP code within the standard deviation.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.51-64
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• 2015

We improved the MODerate resolution Imaging Spectroradiometer (MODIS) land cover map over the Asia-Oceania region through the reclassification of the misclassified pixels. The misclassified pixels are defined where the number of land cover types are greater than 3 from the 12 years of MODIS land cover map. The ratio of misclassified pixels in this region amounts to 17.53%. The MODIS Normalized Difference Vegetation Index (NDVI) time series over the correctly classified pixels showed that continuous variation with time without noises. However, there are so many unreasonable fluctuations in the NDVI time series for the misclassified pixels. To improve the quality of input data for the reclassification, we corrected the MODIS NDVI using Correction based on Spatial and Temporal Continuity (CSaTC) developed by Cho and Suh (2013). Iterative Self-Organizing Data Analysis (ISODATA) was used for the clustering of NDVI data over the misclassified pixels and land cover types was determined based on the seasonal variation pattern of NDVI. The final land cover map was generated through the merging of correctly classified MODIS land cover map and reclassified land cover map. The validation results using the 138 ground truth data showed that the overall accuracy of classification is improved from 68% of original MODIS land cover map to 74% of reclassified land cover map.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.157-166
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• 2005

This article involves architecting prototype-fuzzy expert system for designing the nominal cover thickness by means of fuzzy inference for quantitatively representing the environment affecting factor to reinforced concrete in chloride-induced corrosion environment. In this work, nominal cover thickness to reinforcement in concrete was determined by the sum of minimum cover thickness and tolerance to that defined from skill level, constructability and the significance of member. Several variables defining the quality of concrete and environment affecting factor (EAF) including relative humidity, temperature, cyclic wet and dry, and the distance from coast were treated as fuzzy variables. To qualify EAF the environment conditions of cycle degree of wet-dry, relative humidity, distance from coast and temperature were used as input variables. To determine the nominal cover thickness a qualified EAF, concrete grade, and water-cement ratio were used. The membership functions of each fuzzy variable were generated from the engineering knowledge and intuition based on some references as well as some international codes of practice.

• Journal of Forest and Environmental Science
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• v.36 no.3
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• pp.187-198
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• 2020

This study extracted deforestation area and degraded forestland area, which are potential REDD+ (Reducing Emissions from Deforestation and Forest Degradation) project candidate areas in Paraguay using Land Cover Map (LCM) and Tree Cover Map (TCM). The REDD+ project objectives scenarios were set three stages: 'afforestation and economic efficiency scenario', 'local capacity reinforcement scenario', and 'Infrastructure-oriented scenario'. And then, we evaluated the project unit suitable area of the REDD+ project. All scenarios selected the evaluation factors for each scenario in addition to the area ratio factors for deforestation area and degraded forestland area and weighted values were extracted by assigning category scores. As a result of the three scenarios comparison analysis, Concepcion state score was the highest. Within Concepcion state, the Belon district had the highest score, making it appropriate as a project unit REDD+ project candidate area in Paraguay, while the San Carlos district had the lowest score. This study can be used as basic data for selecting REDD+ project candidate area in Paraguay, and it is expected to contribute sufficiently to REDD+ project if additional data or information of social, cultural and economic sectors are secured.

• ALGAE
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• v.24 no.1
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• pp.31-38
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• 2009

The brown algae padina concrescens is widely distributed in the northwestern Pacific Mexico. We described the population of P. concrescens based on population parameters such as cover, density and size structure and reproduc-tion at two levels tide at the intertidal area in the southwestern Baja. California Peninsula. Monthly visits from January to December 2003 were done. Both cover and density were measured in situ by quadrants method. Samples were collected to obtain size structure and percentage of reproductive fronds. Our results show there is sparial vari-ation in the population structure more than temporal. Thus, cover and density peak were at different months ineach tide level studied, the lower tide level shows the high values in cover as well as density. The frond develop-ment was observed in height/width ratio this relation was consistent only in the low tidal zone. Size class distribu-tion has consistently small size plants in both tide levels.Reproduction was seasonal in the tide channel but in both tide levels all the reproductive plants were tetrasporophyte. Our results suggest that this population is pseudopere-nial and it strongly as a consequence of the intense competition in the intertidal zone.

• Journal of Environmental Science International
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• v.30 no.10
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• pp.779-787
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• 2021

This study analyzes structural landscape changes over a time-series for a small and medium-sized city, Gangneung-Si, based on area and distribution patterns, and according to the type of land cover. Among the types of land cover, the area ratio of urbanized areas increased by 2.02% in the late 2010s as compared to the late 1980s, while there was a decrease of 2.69% in farmland and 0.69% in grassland areas. On analyzing the changes in land cover use by applying the Fragstats program, it was confirmed that landscape changes in urban and management areas were relatively severe according to the Landscape Shape Index, Largest Patch Index, and Aggregation Index. A pattern of concentrated expansion was also found around certain areas. In particular, from the analysis, it was established that the proportion of urbanized area had considerably increased and that the extent of farmland damage to management areas, including planned management areas, was large. Additionally, the Total Core Area generally indicated a reduction in the core areas of farmland and forest within urban and management areas. A medium-sized city showed significant changes besides large cities in terms of landscape structure. The developmental pressure on management areas, in particular, was quite high.