• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.219-224
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• 2007

We conducted geophysical surveys to detect antitank mine at Namji-eup, Gyeongsangnam-do which had been installed during Korean war. The surveys consisted of 2 stages, at the first stage we divided the survey area into 7 block and carried out magnetic gradient survey and GEM-3 EM survey sequentially for each block. Hence we verified anomaly areas using an excavator and a metal detector. Most of anomalies were found to be garbages such as trash cans, metallic wastes, and so on. And also, the concrete pipe was found at depth of 1 m, which had not referred in any report of that area. At the second stage, after trenching the covered soil down to 75 cm the same surveys were conducted. We could not find the strong signal to be inferred from a antitank mine, but we pointed out some anomalies to need careful handling because demining is very dangerous work even though there is few possibility that is mine.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.55-62
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• 1995

This study was conducted to investigate the distribution pattern of plants on streamside of Kyonganchon, which is a tributary of the Han River, and to determine the relationships between plant distribution and environmental factors. Fifteen study sites were selected along the Kyonganchon, and vegetation distribution pattern and soil environmental factors were determined. The most frequently ocurring species in the study sites were Persicaria thunbergii, Persicaria hydropiper, Echinochloa crus-galli and Bidens frondosa, and among them the two Persicaria species were dominants of the community. Many species showed different distribution along the stream:Chenopodium album, Equisetum arvense and Setaria viridies occurred in the upstream region, while Rumex crispus, Leonurus sibiricus and Rorippa islandica occurred in the middle and downstream regions. Analysis of soil properties showed that organic matter and clay content were higher in the upstream region while sand content was higher in the downstream region. The results of DCA ordination showed that axis one was positively correlated with organic matter and clay content and negatively correlated with sand content, indicating that the distribution pattern of vegetation along the Kyonganchon was determined by elevational gradient from upstream to downstream region or gradient of stream width and water level, and by soil organic matter content and soil texture related to these gradients.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.4
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• pp.144-152
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• 1985

This paper temperature gradient thermally stimulated surface potentian (TG-TSSP) in measurements are applied to the study of the polarity of trapped and ionic carriers in cross-linked polyethylene (XLPE) filsm. In the thermally stimulated current in uniform temperature (TSC) of XLPE five peaks appear as indicated of the A B C D and E. In this paper A (at about -120$^{\circ}C$) D (at about 70$^{\circ}C$) and E (at about 110$^{\circ}C$) peaks are investigated. A peak is due to the biassing voltage and biassing temperature. Appear in to the glass transition temperature territory and caused in to the polarization of dipole. D peak is due to the depolarization of ionic space charge and E peak due to the detrapping of carriers injected from the electrodes. TG-TSSP and TSSP are measured to study the polarity of ionic carrier (D peak). In the unsatureated region of ionic space charge polarization, TG-TSSP is lower than TSSP during the initial stage of heating. Result of the experiment for E peak, TG-TSSP is higher than TSSP during the initial stage of heating and these results do not depend on the polarity of biassing voltage, and E peak is concerned with positive carriers (Holes).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.11
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• pp.30-41
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• 2010

In this study we propose a new texture feature extraction method based on an estimation of the brightness and structural uniformity of CT images representing the important characteristics for emphysema recognition. The Center-Symmetric Local Binary Pattern (CS-LBP) is first used to combine gray level in order to describe the brightness uniformity characteristics of the CT image. Then the gradient orientation difference is proposed to generate another CS-LBP code combining with gray level to represent the structural uniformity characteristics of the CT image. The usage of the gray level, CS-LBP and gradient orientation differences enables the proposed method to extract rich and distinctive information from the CT images in multiple directions. Experimental results showed that the performance of the proposed method is more stable with respect to sensitivity and specificity when compared with the SGLDM, GLRLM and GLDM. The proposed method outperformed these three conventional methods (SGLDM, GLRLM, and GLDM) 7.85[%], 22.87[%], and 16.67[%] respectively, according to the diagnosis of average accuracy, demonstrated by the Receiver Operating Characteristic (ROC) curves.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.775-779
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• 2002

Currently, high-resolution satellite imagery such as KOMPSAT and IKONOS has been tentatively utilized to various types of urban engineering problems such as transportation planning, site planning, and utility management. This approach aims at software development and followed applications of remotely sensed imagery to transportation geographic analysis. At first, GDPA (Gradient Direction Profile Algorithm) and main modules in it are overviewed, and newly implemented results under MS visual programming environment are presented with main user interface, input imagery processing, and internal processing steps. Using this software, road network are automatically generated. Furthermore, this road network is used to transportation geographic analysis such as gamma index and road pattern estimation. While, this result, being produced to do-facto format of ESRI-shapefile, is used to several types of road layers to urban/transportation planning problems. In this study, road network using KOMPSAT EOC imagery and IKONOS imagery are directly compared to multiple road layers with NGI digital map with geo-coordinates, as ground truth; furthermore, accuracy evaluation is also carried out through method of computation of commission and omission error at some target area. Conclusively, the results processed in this study is thought to be one of useful cases for further researches and local government application regarding transportation geographic analysis using remotely sensed data sets.

• Korean Journal of Remote Sensing
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• v.19 no.5
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• pp.393-402
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• 2003

In times of the civil uses of commercialized high-resolution satellite imagery, applications of remote sensing have been widely extended to the new fields or the problem solving beyond traditional application domains. Transportation application of this sensor data, related to the automatic or semiautomatic road extraction, is regarded as one of the important issues in uses of remote sensing imagery. Related to these trends, this study focuses on automatic road extraction using Gradient Direction Profile Algorithm (GDPA) scheme, with IKONOS panchromatic imagery having 1 meter resolution. For this, the GDPA scheme and its main modules were reviewed with processing steps and implemented as a prototype software. Using the extracted bi-level image and ground truth coming from actual GIS layer, overall accuracy evaluation and ranking error-assessment were performed. As the processed results, road information can be automatically extracted; by the way, it is pointed out that some user-defined variables should be carefully determined in using high-resolution satellite imagery in the dense or low contrast areas. While, the GDPA method needs additional processing, because direct results using this method do not produce high overall accuracy or ranking value. The main advantage of the GDPA scheme on road features extraction can be noted as its performance and further applicability. This experiment study can be extended into practical application fields related to remote sensing.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.694-706
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• 2019

In this study, we applied the long short-term memory (LSTM) model to classify the cryptocurrency price time series. We collected historic cryptocurrency price time series data and preprocessed them in order to make them clean for use as train and target data. After such preprocessing, the price time series data were systematically encoded into the three-dimensional price tensor representing the past price changes of cryptocurrencies. We also presented our LSTM model structure as well as how to use such price tensor as input data of the LSTM model. In particular, a grid search-based k-fold cross-validation technique was applied to find the most suitable LSTM model parameters. Lastly, through the comparison of the f1-score values, our study showed that the LSTM model outperforms the gradient boosting model, a general machine learning model known to have relatively good prediction performance, for the time series classification of the cryptocurrency price trend. With the LSTM model, we got a performance improvement of about 7% compared to using the GB model.

• Steel and Composite Structures
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• v.42 no.1
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• pp.23-32
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• 2022

In this paper, a nonlinear numerical method to solve the large deflection problem is introduced. And the non-dimensional load-deflection behavior of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates is parametrically investigated. The large deflection problem is formulated according to the von Kármán nonlinear theory and the (1,1,0)^* hierarchical model, and it is approximated by 2-D natural element method (NEM). The shear locking phenomenon is suppressed by the selectively reduced integration method. The nonlinear matrix equations are solved by combining the incremental loading scheme and the Newton-Raphson iteration method. The proposed method is validated from the benchmark experiments, where the propose method shows an excellent agreement with the reference methods. The nonlinear behavior of FG-CNTRC plates is evaluated in terms of the non-dimensional load-deflection curve, and it is parametrically investigated with respect to the existence/non-existence and gradient pattern of CNTs, the width-to-thickness and aspect ratios of plates and the type of boundary conditions. The non-dimensional central deflection is significantly reduced when CNTs and added, and it decreases with the volume fraction of CNTs. But, it shows a uniform increase in proportion to the width-to-thickness and aspect ratios. Both the gradient pattern of CNTs and the type of boundary conditions do also show the remarkable effects.

• Journal of Soil and Groundwater Environment
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• v.28 no.6
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• pp.45-57
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• 2023

To assess land subsidence estimation and preparedness in the Geum River basin, this study applied GIS techniques and identified six key areas. The Geum River basin has experienced an increase in heavy rainfall since late 2010, and four study areas have shown an increase in groundwater levels. Land subsidence primarily occurred from June to September, with higher rainfall years in 2020 and 2023. Approximately 83.6% of land subsidence in Chungcheongbuk-do province occurred in Cheongju-si, mainly attributed to aging sewage pipes. The regions experiencing population growth have likely led to the construction of underground infrastructures and sewer pipes. Thus, it is considered that various factors, including sewage pipe leaks, precipitation, slope gradient, low drainage density, and groundwater level fluctuations, have contributed to land subsidence. Improving land subsidence estimation involves incorporating additional natural factors and human activities.

• Korean Journal of Medicinal Crop Science
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• v.27 no.5
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• pp.322-329
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• 2019

Background: Studies have suggested that the northern provinces of Gangwon-do are good sites for licorice (Glycyrrhiza uralensis Fisch.) cultivation in Korea, as they have similar temperatures to its original locations in northern China. However, poor growth and freezing injury are often reported in Korea. Therefore, it is necessary to reassess the domestic cultivation site of licorice. Methods and Results: To determine the optimum temperature for cultivating licorice, the growth, yield, and pharmacological characteristics of G. uralensis were assessed in a temperature gradient tunnel at Eumseong, Chungcheongbuk-do, Korea in 2017. Plant height increased until the temperature rose to $5.9^{\circ}C$ above the local external temperature. Yield (㎏/10a) increased by 46.9% when the growing temperature was $1.5^{\circ}C$ to $3.0^{\circ}C$ (T2) above the external temperature and by 72.6% when the growing temperature was $3.0^{\circ}C-4.5^{\circ}C$ (T3) above the external temperature. However, a difference of $4.5^{\circ}C-5.9^{\circ}C$ (T4) above the external temperature, decreased the yield by 9.8% compared to that at T2. The glycyrrhizin content of G. uralensis roots in each temperature band was 0.72%, 0.53%, 0.91%, and 0.84% (T1, T2, T3, T4), these differences appear to result form individual plant variation rather than growth temperature. Conclusions: Based on the results of this study, we estimate that the temperature-based optimum cultivation site for G. uralensis in Korea is the south central region, rather than the northern province of Gangwon-do. Improvement in growth and yield maybe observed if the plantations in the central Jecheon (Chungcheongbuk-do, Korea) are expanded into the south central region.