• Korean Journal of Remote Sensing
• /
• v.36 no.2_2
• /
• pp.277-292
• /
• 2020

The purpose of this study is to propose the possibility of precise surface sedimentary facies classification and a more accurate classification method by generating the large-scale map of surface sedimentary facies based on UAV data and object-based image analysis (OBIA) for Hwang-do tidal flat in Cheonsu bay. The very high resolution UAV data extracted factors that affect the classification of surface sedimentary facies, such as RGB ortho imagery, Digital elevation model (DEM), and tidal channel density, and analyzed the principal components of surface sedimentary facies through statistical analysis methods. Based on principal components, input data to be used for classification of surface sedimentary facies were divided into three cases such as (1) visible band spectrum, (2) topographical elevation and tidal channel density, (3) visible band spectrum and topographical elevation, tidal channel density. The object-based image analysis classification method was applied to map the classification of surface sedimentary facies according to conditions of input data. The surface sedimentary facies could be classified into a total of six sedimentary facies following the folk classification criteria. In addition, the use of visible band spectrum, topographical elevation, and tidal channel density enabled the most effective classification of surface sedimentary facies with a total accuracy of 63.04% and the Kappa coefficient of 0.54.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_1
• /
• pp.537-549
• /
• 2023

The distribution characteristics of tidal flat sediment components are used as an essential data for coastal environment analysis and environmental impact assessment. Therefore, a reliable classification map of surface sedimentary facies is essential. This study evaluated the applicability of regression kriging to generate a classification map of the sedimentary facies of tidal flats. For this aim, various factors such as the number of field survey data and remote sensing-based auxiliary data, the effect of regression models on regression kriging, and the comparison with other prediction methods (univariate kriging and regression analysis) on surface sedimentary facies classification were investigated. To evaluate the applicability of regression kriging, a case study using unmanned aerial vehicle (UAV) data was conducted on the Hwang-do tidal flat located at Anmyeon-do, Taean-gun, Korea. As a result of the case study, it was most important to secure an appropriate amount of field survey data and to use topographic elevation and channel density as auxiliary data to produce a reliable tidal flat surface sediment facies classification map. In addition, regression kriging, which can consider detailed characteristics of the sediment distributions using ultra-high resolution UAV data, had the best prediction performance compared to other prediction methods. It is expected that this result can be used as a guideline to produce the tidal flat surface sedimentary facies classification map.

• Geophysics and Geophysical Exploration
• /
• v.23 no.3
• /
• pp.157-167
• /
• 2020

With the recent advancement of computer hardware and the contribution of open source libraries to facilitate access to artificial intelligence technology, the use of machine learning (ML) and deep learning (DL) technologies in various fields of exploration geophysics has increased. In addition, ML researchers have developed complex algorithms to improve the inference accuracy of various tasks such as image, video, voice, and natural language processing, and now they are expanding their interests into the field of automatic machine learning (AutoML). AutoML can be divided into three areas: feature engineering, architecture search, and hyperparameter search. Among them, this paper focuses on hyperparamter search with Bayesian optimization, and applies it to the problem of facies classification using seismic data and well logs. The effectiveness of the Bayesian optimization technique has been demonstrated using Vincent field data by comparing with the results of the random search technique.

• Journal of Wetlands Research
• /
• v.7 no.2
• /
• pp.121-132
• /
• 2005

To classify the surface sedimentary facies using IKONOS image collected over Hwangdo tidal flat in Cheonsu Bay, the optical reflectance was compared for characterizing various sedimentary environments such as grain size, tidal channel pattern and area ratio of surface remnant water. The intertidal DEM (Digital Elevation Model) was generated by echo-sounder for analyzing the relationship between IKONOS image and sedimentary environments including topography. The boundary of the optical reflectance between mud-mixed facies and sand facies was distinct, and discrimination of the associated sandbar feature was also possible. The mud-mixed facies coupled with intricate tidal channels is confined to the relatively hi호 topography of Hwangdo tidal flat. The boundary between mud and mixed flat was indistinct in IKONOS optical reflectance but it would have a difference in the area ratio of surface remnant water. The dark area in the image represented the well developed sand facies having a lot of surface remnant water due to the relatively low surface topography. The overall accuracy of characterizing the surface sediment facies by maximum likelihood classification method was 86.2 %. These results demonstrate that high spatial resolution satellite imagery such as IKONOS coupled with knowledge of grain size, surface remnant water and tidal channel network can be effectively used to characterize the surface sedimentary facies (mud, mixed and sand) network of the tidal flat environments.

• Economic and Environmental Geology
• /
• v.44 no.1
• /
• pp.59-70
• /
• 2011

The surface sediment distribution in a tidal flat in 2001 was compared with that of 2008 using high spatial resolution remote sensing images and a GIS-based analysis. Maps of the surface sedimentary facies for each time frame were induced by an IKONOS data acquired in February, 2001 and a KOMPSAT-2 data acquired in April, 2008 using an object-based classification method. The area ratio of each surface sedimentary facies were estimated, and the results were compared each other for deducing the change in the sedimentary facies during the time interval. The result showed that the percentage of grains larger than very fine sand (0.0625 mm) has increased considerably since the early 2000s in the Hwangdo tidal flat. Mud flat facies has decreased 5.81 % in the late 2000s compared with the early 2000s. However, mixed flat and sand flat have increased 4.46% and 2.14%, respectively. A field campaign also supported the result. This study showed that the monitoring of changes in the surface sedimentary facies in the tidal flat is possible through a GIS-based analysis using high spatial resolution remote sensing images.

• Geophysics and Geophysical Exploration
• /
• v.2 no.4
• /
• pp.202-208
• /
• 1999

We introduce a new acoustic parameter for the classification of seafloor sediments from chirp sonar acoustic profiling data. The acoustic parameter is defined as a derivative of the unwrapped phase of the Fourier transform of acoustic profiling data. Consequently, it represents the characteristics of attenuation by dissipative dispersion in sediments. And we estimated acoustic properties by geoacoustic modeling using Chirp data obtained from the different sedimentary facies. Our classification results, when compared with the results of analysis of sampled sediments, show that the acoustic parameter discriminates sedimentary facies and bottom hardness. Thus the method in this paper is expected to be an effective means of geoacoustic modeling of the seafloor.

• Geophysics and Geophysical Exploration
• /
• v.23 no.3
• /
• pp.131-140
• /
• 2020

In training a classification model using machine learning, the acquisition of training data is a very important stage, because the amount and quality of the training data greatly influence the model performance. However, when the cost of obtaining data is so high that it is difficult to build ideal training data, the number of samples for each class may be acquired very differently, and a serious data-imbalance problem can occur. If such a problem occurs in the training data, all classes are not trained equally, and classes containing relatively few data will have significantly lower recall values. Additionally, the reliability of evaluation indices such as accuracy and precision will be reduced. Therefore, this study sought to overcome the problem of data imbalance in two stages. First, we introduced weighted accuracy and weighted precision as new evaluation indices that can take into account a data-imbalance ratio by modifying conventional measures of accuracy and precision. Next, oversampling was performed to balance weighted precision and recall among classes. We verified the algorithm by applying it to the problem of facies classification. As a result, the imbalance between majority and minority classes was greatly mitigated, and the boundaries between classes could be more clearly identified.

• Korean Journal of Korean Medical Institute of Dermatology and Aesthetics
• /
• v.1 no.1
• /
• pp.114-126
• /
• 2005

Objectives : The results of this study have given an insight into the clinical effects of Chungsang-bangpoong-tang, Gami-bunso-tang, Chogyung-san on treatments against Acne patients. Methods : We are investigated with deciphered-Acne 54 cases at the division of dermatology in Jaseng oriental medicine hospital from 9, August 2000 to until 26, February 2001. To demonstrated in accordance with patients, orally administrated with Chungsang-bangpoong-tang, Gami-bunso-tang, Chogyung-san, respectively. Results : These results found that sex distinction with a disease caused much more 85.2% female than 14.8% male in the proportion of males to females. specifically, which is mainly ranked with 21 to 25 years of female and 26 to 30 years of male. On the hand, the distribution interval of a case history is broadly followed by disease below 10 to 35 years in male, whereas 21 to 25 years in female. Also, interval of the period-treatment is indicated within more than five years both female and male. In point-lesion, facies is majority and according to the cheek, jaw, back, frontal and the whole body, respectively. Specifically, mainly appeared according to the facies, back, whereas facies, cheek in female. In Distribution of Symptomic Identification, most of them is 肺經風熱, and then 衝任不調型, 脾胃濕熱, Etc. The self-assessment of total is Excellent 4 cases, Good 4 cases, Fair 11 cases, Poor 2 cases. Conclusions : These results suggest that in the identify of symptoms as 肺經風熱, 脾胃濕熱, 衝任不調型 may be playa role in the significant usefulness and have need of application for the clinical trials against Acne' patients.

• The Korean Journal of Quaternary Research
• /
• v.24 no.1
• /
• pp.35-45
• /
• 2010

The aims of this study are to clarify the geomorphological development of a alluvial plain and discuss the vegetation environments and agriculture activities in the Wangpo-River alluvial plain at Neungsan-ri, Buyeo by analyzing geomorphological classification, sedimentary facies and age datings. The alluvial plain at Wangpo-River was formed by the influences of Geum-River with the sea-level rising during the Holocene. The basin of Wangpo-River consists of natural levees, back marsh-type alluvial plains, valley plains and hills. The natural levees by Geum-River largely distributes at the area where Wangpo-River flows to Geum-River and the alluvial plains at the middle and lower reach are the back marsh areas of Geum-River. Moreover, the area along Wangpo-River show higher contents of coarse materials and thinner peat sediments than the back marsh. The lower sandy deposits in the alluvium of Wangpo-River was formed with the influences of human in the Bronze Age during the sea level falling and the peaty deposits was formed due to the water level rising of Wangpo-River during the sea level rising in the early Iron Age.

• The Korean Journal of Ecology
• /
• v.9 no.4
• /
• pp.209-223
• /
• 1986

The forest stands of Seonusan area, South-western Korea, were classified into three alliances and nine communities by the Z-M school scheme. Of these one alliance and four association were recognized in this study, that is, an alliance, Carpinion laxiflorae and four associations, Casrpinetum tschonoskii, Quercetum variabilis, Carpinetum laxiflorae and Rhododendro mucronulati-Pinetum densiflorae. Hierachy of Seonunsan area forest vegetation by Z-M scheme was as fallows: Pinion densiflorae Suz.-Tok. 1966. 1. Rhododendro mucronlati-Pinetum densiflorae ass.l nov., 2. Pinus thunbergii community. Carpinion laxiflorae all. nov., 1. Quercus serrata-Carpinus tschonoskii community, 2. Quercus aliena-Carpinus tschonoskii community, 3, Carp inetum tschonoskii ass. nov., a. Typical subass., b. Sasa borealis subass. 4. Quercetum variabilis ass. nov., a Sasa borealis subass. b. Typical subass, 5. Carpinetum laxiflorae ass. nov., Zelkovion serratae Miyawaki et al., 1977., 1. Orixo-Zelk ovetum serratae Miyawaki et H. Tohma 1975., a Typical subass., b. Thea sinensis facies, 2. Thea sinensis-Camellia japonica community.