• Korean Journal of Remote Sensing
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• v.31 no.4
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• pp.293-302
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• 2015

Water body extraction is significant for flood disaster monitoring using satellite imagery. Conventional methods have focused on finding an index, which highlights water body and suppresses non-water body such as vegetation or soil area. The Normalized Difference Water Index (NDWI) is typically used to extract water body from satellite images. The drawback of NDWI, however, is that some man-made objects in built-up areas have NDWI values similar to water body. The objective of this paper is to propose a new method that could extract correctly water body with built-up areas in before and after images of flood. We first create a two-element feature vector consisting of NDWI and a Near InfRared band (NIR) and then select a training site on water body area. After computing the mean vector and the covariance matrix of the training site, we classify each pixel into water body based on Mahalanobis distance. We also register before and after images of flood using outlier removal and triangulation-based local transformation. We finally create a change map by combining the before-flooding water body and after-flooding water body. The experimental results show that the overall accuracy and Kappa coefficient of the proposed method were 97.25% and 94.14%, respectively, while those of the NDWI method were 89.5% and 69.6%, respectively.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.598-601
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• 2007

Urban growth management is essential for sustainable urban growth. Monitoring physical urban built-up area is a task of great significance to manage urban growth. Detecting urbanized area is essential for monitoring urbanized area. Although image classifications using satellite imagery are among the conventional methods for detecting urbanized area, they requires very tedious and hard work, especially if time-series remote sensing data have to be processed. In this paper, we propose an effective urbanized area detecting method based on normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI). To verify the proposed method, we extract urbanized area using two methods; one is conventional supervised classification method and the other is the proposed method. Experiments shows that two methods are consistent with 98% in 1998, 99.3% in 2000, namely the consistency of two methods is very high. Because the proposed method requires no more process without band operations, it can reduce time and effort. Compared with the supervised classification method, the proposed method using vegetation indices can serve as quick and efficient alternatives for detecting urbanized area.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.1 s.118
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• pp.55-64
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• 2007

In the built-up structure consisting of a stiff beam and a flexible plate, Grice showed that the plate behaves as an energy absorber in narrow frequency bands(called plate blocking effect). This paper deals with such beam-plate coupled structures, where the plate is an energy absorber and the excited beam is an energy path. It is found that such energy dissipation can occur in the relatively broad bands, if different stiffnesses are used in the rectangular plate. It was experimentally verified by Heckl that the energies in terms of one-third octave band averages transferred to the plate(or dissipated in the plate) increase for increased plate damping. This Paper, however, shows that the energy absorption suddenly reduces at the certain narrow frequency bands where the plate damping effect upon the coupled beam is maximum. Also, in order to minimize energy transfer through the beam in terms of one-third octave band averages, it is advantageous to increase the plate damping closer to the excitation point All these results are based on the wane method.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.120-129
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• 2007

Rapid urbanization has transformed the spatial pattern of urban land use or cover. This paper concentrates that changed characteristics of landscape structure in the Tancheon Watershed, from 1995 to 2003 were investigated using land cover map. We used FRAGSTATS software to calculate landscape indices to characterize the landscape structure. We found that built up area has been increased rapidly during the study period, while cultivated area and forest area have been decreased rapidly in the same period. From 1995 to 2003, built up area was increased from 19.73% to 39.62% and cultivated area and forest area was decreased 17.60% to 5.97% and 58.31% to 49.41%. Number of patches, mean euclidean nearest-neighbor distance, contagion index, Shannon's diversity index increased considerably from 1995 to 2003, also suggesting the landscape in the study area became more fragmented and heterogeneous. but because of continuously fragmentation, landscape became homogeneity. The study demonstrates that landscape metrics can be a useful indicator in landscape monitoring and landscape assessment.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.5
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• pp.120-129
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• 2000

This main study was the subject of the play facilities of children picnicking place which was installed in apartment complex. As to the production period of the facilities, the materiality and the materials of the play facilities, we examined the safety estimation about them. And we drew up a plan which could build and manage the children play facilities improved the better. According to the installation place, the result of safety estimation, the safety of play facilities in Ga-Kyeong-dong apartment complex which built up after 1997 years was the most excellent, the play facilities of Sa-Gik-Dong apartment Complex which built long ago have showed even poorer in all items of safety estimation. According to the materiality of play facilities, though the safety of association play rod in the safety estimation was the most excellent, the safety of swing was the very poor. According to the materiality of materials, the association of wood, stainless in the safety estimation was the safest. Especially, even though wood is soft and kind materials, as it has a shortcoming, the practical use depreciates. If iron materials like stainless associates with wood, we have thought that they have the good effect of the practical use. We have judged that the distance of contiguity facilities and the safety of corrosion or rottenness within the item of safety estimation as a subordination variable were the poorest. The arrangement of play facilities and the selection of materials happened to these problems. And we have known that they should get accomplished the construction work to make a plan thoroughly from it early.

• Steel and Composite Structures
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• v.8 no.4
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• pp.313-328
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• 2008

This study attempts to suggest bending reinforcement method by applying bending reinforcement to composite profile beam in which the concept of prefabrication is introduced. Profile use can be in place of framework and is effective in improvement of shear and bending strength and advantageous in long-term deflection. As a result of experiment, MPB-CB2 with improved module had higher strength and ductility than the previously published MPB-CB and MPB-LB. In case of bending reinforcement with deformed bar and built-up T-shape section based on MPB-CB2, the MPB-RB series reinforced with deformed bar were found to have higher initial stiffness, bending strength and ductility than the MPB-RT series. The less reinforcement effect of the MPB-RT series might be caused by poor concrete filling at the bottom of the built-up T-shape. In comparison between theoretical values and experimental values using minimum yield strength, the ratio between experimental value and theoretical value was shown to be 0.9 or higher except for MPB-RB16 and MPB-RT16 that have more reinforcement compared to the section, thus it is deemed that the reinforced modular composite profiled beam is highly applicable on the basis of minimum yield strength.

• Journal of the Korea Safety Management & Science
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• v.4 no.4
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• pp.137-146
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• 2002

In order to investigate the effect of irradiation by $^{60}Co-\gamma$rays as well as the e thermal treatment on the dielectric deterioration in ethylene propylene rubber, insulating material for electric cables used in atomic power plants, charging discharging current, residual built- up voltage and dielectric properties are measu discussed in this study. Variance in the characteristic of relative dielectric constant as a function of tem was observed in relatively high dose of irradiation. Since glass transition tem appeared at tens of degree Celsius below zero, the characteristic is attributed orientation polarization. Dielectric loss is generally increased, with increasing d irradiation in the characteristic of dielectric loss as a function of temperature, No d loss by thermal treatment was observed. Dielectric resistance decreases with increa of irradiation in the characteristic of charging current as a function of temperature be considered that dielectric resistance seems to be recovered by thermal treatm characteristic of discharging current as a function of time in the specimen less ir become similar to that of the unirradiated, when thermal treated. A peak is shown residual built- up voltage as a function of time, and the corresponding time of the shorten as increasing dose of irradiation. It is also observed that the corresponding the peak is lengthened by thermal treatment.

• Journal of the Korean housing association
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• v.24 no.3
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• pp.27-35
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• 2013

The purpose of this study is to develop an evaluation system for integrative comfort values of Hanok residence. For this study, a mock-up located in Yongin, Gyeonggi province built by an ongoing governmental research project has been chosen. Then, SSN (Smart Sensor Network) has been utilized for monitoring quantitative factors in the environment and detailed face-to-face surveys have been performed for analyzing qualitative comfort indexes from residents in the experimental settings. Then, this study employs a combined evaluation system using AHP (Analytic Hierarchy Process) established for estimating overall DIC (Degree of Integrative Comfort) of the Hanok residence. As a result, the evaluation system could verify the total comfort indexes of Hanok residence and suggest converged methodologies for establishing value assessment system for traditional residential facilities. The method of DIC suggested in this paper would be examined with current residents in a built mock-up to see its applicability as a comprehensive evaluation model, and it is expected that collected year-round comfort data from the facility would provide more practical information towards future strategies for the Hanok residence.

• Korean Journal of Remote Sensing
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• v.23 no.3
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• pp.181-188
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• 2007

The objective of this research was to investigate the optimal land cover classification algorithm for the monitoring of North Korea with MODIS multi-temporal data based on monthly phenological characteristics. Three frequently used land cover classification algorithms, ISODATA1), SMA2), and SOM3) were employed for this study; the land cover categories were forest, grass, agricultural, wetland, barren, built-up, and water body. The outcomes of the study can be summarized as follows. First, the overall classification accuracy of ISODATA, SMA, and SOM was 69.03%, 64.28%, and 73.57%, respectively. Second, ISODATA and SMA resulted in a higher classification accuracy of forest and agricultural categories, but SOM performed better for the built-up area, bare soil, grassland, and water. A possible explanation for this difference would be related to the difference of sensitivity against the vegetation activity. This would be related to the capability of SOM to express all of their values without any loss of data by maintaining the topology between pixels of primitive data after classification, while ISODATA and SMA retain limited amount of data after normalization process. Third, we can conclude that SOM is the best algorithm for monitoring the land cover change of North Korea.

• Korean Journal of Remote Sensing
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• v.35 no.4
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• pp.561-571
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• 2019

In this paper, we analyze the effect of the representative spectral indices, normalized difference vegetation index (NDVI), normalized difference water index (NDWI) and normalized difference built-up index (NDBI) on classification accuracies of Landsat-8 OLI image.After creating these spectral index images, we propose five methods to select the spectral index images as classification features together with Landsat-8 OLI bands from 1 to 7. From the experiments we observed that when the spectral index image of NDVI or NDWI is used as one of the classification features together with the Landsat-8 OLI bands from 1 to 7, we can obtain higher overall accuracy and kappa coefficient than the method using only Landsat-8 OLI 7 bands. In contrast, the classification method, which selected only NDBI as classification feature together with Landsat-8 OLI 7 bands did not show the improvement in classification accuracies.