• Journal of The Geomorphological Association of Korea
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• v.17 no.1
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• pp.59-72
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• 2010

This study is based on the observation on the patterned ground found in the northern part of the Baekdusan during two fieldtrips of 2008 summer. The patterned grounds are found in two areas-Dalmun and Socheonji. The patterned ground found around Dalmun are well-sorted, having fine materials in the center and coarse (boulder size) materials in the rim, and stretching in the form of stairs. Meanwhile, the types of patterned ground found around Socheonji are various, including polygon, stripe, and circular patterns. The particle size analysis and morphological analysis of comprising materials are carried out only for the patterned ground of Socheonji. The mean short and long axis of the patterned grounds are 91cm and 163cm, respectively. The distribution pattern of material size from the most samples increase toward the rim, indicating the patterned grounds are well-sorted. The comprising materials are dominated by silt, which is very susceptible for freeze-thaw cycle. The lower ratio of clay (low less than 10%), suggests that physical weathering is more dominant rather than chemical weathering. The involution structure found in the vertical section of the patterned grounds is likely to have formed by active cryoturbation which is one of the dominant geomorphic processes in the periglacial environments like the study area.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.3
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• pp.166-172
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• 2022

In this study, we photograph driving obstacle objects such as crosswalks, side spheres, manholes, braille blocks, partial ramps, temporary safety barriers, stairs, and inclined curb that hinder or cause inconvenience to the movement of the vulnerable using electric mobility aids. We develop an optimal AI model that classifies photographed objects and automatically recognizes them, and implement an algorithm that can efficiently determine obstacles in front of electric mobility aids. In order to enable object detection to be AI learning with high probability, the labeling form is labeled as a polygon form when building a dataset. It was developed using a Mask R-CNN model in Detectron2 framework that can detect objects labeled in the form of polygons. Image acquisition was conducted by dividing it into two groups: the general public and the transportation weak, and image information obtained in two areas of the test bed was secured. As for the parameter setting of the Mask R-CNN learning result, it was confirmed that the model learned with IMAGES_PER_BATCH: 2, BASE_LEARNING_RATE 0.001, MAX_ITERATION: 10,000 showed the highest performance at 68.532, so that the user can quickly and accurately recognize driving risks and obstacles.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.2
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• pp.119-125
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• 2023

In this study, we photograph driving obstacle objects such as crosswalks, side spheres, manholes, braille blocks, partial ramps, temporary safety barriers, stairs, and inclined curb that hinder or cause inconvenience to the movement of the vulnerable using electric mobility aids. We develop an optimal AI model that classifies photographed objects and automatically recognizes them, and implement an algorithm that can efficiently determine obstacles in front of electric mobility aids. In order to enable object detection to be AI learning with high probability, the labeling form is labeled as a polygon form when building a dataset. It was developed using a Mask R-CNN model in Detectron2 framework that can detect objects labeled in the form of polygons. Image acquisition was conducted by dividing it into two groups: the general public and the transportation weak, and image information obtained in two areas of the test bed was secured. As for the parameter setting of the Mask R-CNN learning result, it was confirmed that the model learned with IMAGES_PER_BATCH: 2, BASE_LEARNING_RATE 0.001, MAX_ITERATION: 10,000 showed the highest performance at 68.532, so that the user can quickly and accurately recognize driving risks and obstacles.

• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.368-387
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• 2007

In order to explain geomorphological characteristics of the Korean Peninsula, it is necessary to understand the spatial distribution of tectonic movements and its causes. Even though geomorphological elements which might have been formed by tectonic movements(e.g. tilted overall landform, erosion surface, river terrace, marine terraces, etc.) have long been considered as main geomorphological research topics in Korea, the knowledge on the spatial distribution of tectonic movement is still limited. This research aims to identify the spatial distributions of tectonic movement via sequential analyses of Digital Elevation Model(DEM). This paper first developed a set of terrain analysis techniques derived from theoretical interrelationships between tectonic uplifts and landsurface denudation processes. The terrain analyses used in this research assume that elevations along major drainage basin divides might preserve original landsurfaces(psuedo-landsuface) that were formed by tectonic movement with relatively little influence by denudation processes. Psuedo-landsurfaces derived from a DEM show clear spatial distribution patterns with distinct directional alignments. Lines connecting psuedo-landsufaces in a certain direction are defined as psuedo-landsurface axes, which are again categorized into two groups: the first is uplift psuedo-landsurface axes that indicate the axis of landmass uplift; and the second is denudational psuedo-landsurface axes that cross step-shaped pusedo-landsurfaces formed via surface denudation. In total, 13 axes of pusedo-landsurface are identified in the Korean Peninsula, which show distinct direction, length, and relative uplift rate. Judging from the distribution of psudo-landsurfaces and their axes, it is concluded that the Korean Peninsula ran be divided into four tectonic regions, which are named as the Northern Tectonic Region, Center Tectonic Region, Southern Tectonic Region, and East Sea Tectonic Region, respectively. The Northern Tectonic Region had experienced a regional uplift centered at the Kaema plateau, and the rate of uplift gradually decreased toward southern, western and eastern directions. The Center Tectonic Region shows an arch-shaped uplift. Its uplift rate is the highest along the East Sea and the rate decreases towards the Yellow sea. The Southern Tectonic Region shows an asymmetric uplift centered a line connecting Dukyu and Jiri Mountains in the middle of the region. The eastern side of the Southern Regions shows higher uplift rate than that of the western side. The East Sea Tectonic Region includes south-eastern coastal area of the peninsula and Gilju-Myeongchun Jigudae, which shows relatively recent tectonic movements in Korea. Since this research visualizes the spatial heterogeneity of long-term tenonic movement in the Korean peninsula, this would provide valuable basic information on long-term and regional differences of geomorphological evolutionary processes and regional geomorphological differences of the Korean Peninsula.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.223-235
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• 2004

Objectives: This study was to evaluate the actual condition of falls among community-dwelling elderly people and its related factors to prepare for the establishment of comprehensive prevention programs of senior population. Methods: The study subjects included 460 home residents over 65 years in a district of Chungnam Province and interviews were given to all of them, asking about experiences of falls and their related factors. The analysis of study results came to the following conclusions. Results: The rate of falls among total subjects was 35.5%. With the percentage by age and sex, over 70's and female were significantly higher than male(p=0.000) and under 69 (p=0.008). The groups with poor visual acuity and hearing ability had higher rate of falls than the normal groups based on their health status. In terms of place they experienced falls, out-door occurrence accounted for 53.4% of total falls, which was higher 46.6% of in-door. By season when falls are experienced, "winter" showed the greatest rate, and by time of the day, evening had the highest rate. By causes of falls, "Slippery ground"accounted for 30.5% and "Tumbled over" 23.5% of total falls, respectively, showing the major role of environmental causes for falls. For individual factors, "Irritability" and "Carelessness" occupied 11.3%, 10.8% of total falls, respectively. The Odds Ratios for falls in women was 2.19 times higher than in men, and those in 70's are 2.01 times higher than in 60's, and those with abnormal BMI was 3.68 times higher than in normal groups, and those with perceived symptoms was 1.94 times higher than those without. Conclusions: It is suggested that more consideration should be directed toward taking comprehensive and systematic prevention measures ranging from setting-up the injury-protective environments to allowing senior citizens to have competence in ADL activity as well as proper general health conditions, considering the higher rate of falls for elderly persons in a rural part of this country than that of western countries and the greater proportion of falls which can be ascribed to environmental factors.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.447-457
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• 2008

Laboratory tests for single plane sliding were conducted using the model rock slope to investigate the cut slope deformability and failure mechanism due to combined effect of engineering characteristics such as angle of sliding plane, water force, joint roughness and infillings. Also the possibility of prediction of slope failure through displacement monitoring was explored. The joint roughness was prepared in forms of saw-tooth type having different roughness specifications. The infillings was maintained between upper and lower roughness plane from zero to 1.2 times of the amplitude of the surface projections. Water force was expressed as the percent filling of tension crack from dry (0%) to full (100%), and constantly increased from 0% at the rate of 0.5%/min and 1%/min upto failure. Total of 50 tests were performed at sliding angles of $30^{\circ}$ and $35^{\circ}$ based on different combinations of joint roughness, infilling thickness and water force increment conditions. For smooth sliding plane, it was found that the linear type of deformability exhibited irrespective of the infilling thickness and water force conditions. For sliding planes having roughness, stepping or exponential types of deformability were predominant under condition that the infilling thickness is lower or higher than asperity height, respectively. These arise from the fact that, once the infilling thickness exceeds asperities, strength and deformability of the sliding plane is controlled by the engineering characteristics of the infilling materials. The results obtained in this study clearly show that the water force at failure was found to increase with increasing joint roughness, and to decrease with increasing filling thickness. It seems possible to estimate failure time using the inverse velocity method for sliding plane having exponential type of deformability. However, it is necessary to estimate failure time by trial and error basis to predict failure of the slope accurately.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.187-197
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• 2010

The paleoseismological study in Korea has begun along the Yangsan fault zone (YFZ) and Ulsan fault zone (UFZ) since 1994. Some evidences related to late Quaternary movement are found at only some part of the YFZ, such as Pyonghae, Yuge, and Eonyang-Tongdosa areas. However, it is found along the most of the UFZ except the northen and southern ends of the fault. The dominant time span of faulting events along the YFZ and UFZ are quite different, and 500 ka to 200 ka and 300 ka to recent time, respectively. The dominant faulting senses of the YFZ and UFZ are right-lateral strike slip and reverse, respectively. These senses correspond well with the focal mechanism of recent occurring earthquakes along these two fault zones. If we evaluate the intensity of the activity of the YFZ from the average slip rate, which is 0.1~0.04 m/ka, it is comparable with the faults of higher C class in Japan. The slip rate of UFZ, which is 0.2~0.06 m/ka, is comparable with the faults of lower B to higher C class. Based on the relationship between maximum displacement and magnitude, the maximum earthquake magnitude is evaluated to be 6.8 and 7.0 in the YFZ and UFZ, respectively. An intensive studies are needed to clarify the problems such as segmentation of faults, return period, and geological evidences related to historical earthquakes.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.38-47
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• 2013

An image coding based on MRC model, a kind of multi-layer image model, first segments a screen image into foreground, mask, and background layers, and then compresses each layer using a codec that is suitable to the layer. The mask layer defines the position of foreground regions such as textual and graphical contents. The colour signal of the foreground (background) region is saved in the foreground (background) layer. The mask layer which contains the segmentation result of foreground and background regions is of importance since its accuracy directly affects the overall coding performance of the codec. This paper proposes a new layer segmentation algorithm for the MRC based image coding. The proposed method extracts text pixels from the background using morphological top hat filtering. The application of white or black top hat transformation to local blocks is controlled by the information of relative brightness of text compared to the background. In the proposed method, the boundary information of text that is extracted from the edge map of the block is used for the robust decision on the relative brightness of text. Simulation results show that the proposed method is superior to the conventional methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.3
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• pp.273-282
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• 2016

There has been growing social interest recently in the movement rights of people with reduced mobility. However, it simply eliminates the temporary inconvenience of walking of people with reduced mobility because it focuses only on supply of institutional facilities. Therefore, we look forward to improving movement welfare by proposing an optimized path finding algorithm for people with reduced mobility that takes into consideration physical elements affecting their movement, such as slope, steps etc. We selected Walking barrier factor by analyzing previous studies and calculated the relative importance of Walking barrier factors using an Analytic Hierarchy Process(AHP). Next, through the fuzzy system, the Walking disturbance level of link, which integrates the weights of Walking barrier factors and the attributes of each link, is derived. Then, Walking path cost that takes into consideration the ‘length’ factors is calculated and an optimized path for people with reduced mobility is searched using Dijkstra’s Algorithm. Nineteen different paths were searched and we confirmed that the derived paths are meaningful in terms of improving the mobility of people with reduced mobility by conducting a field test. We look forward to improving movement welfare by providing a navigation service using the path finding algorithm proposed in this study.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.2
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• pp.124-133
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• 2014

The study on Musa basjoo planting in traditional gardens in of folk villages and traditional temples was conducted to identify the phenomenon of Musa basjoo planting which frequently appears in paintings and literatures of the late Joseon dynasty and how the cultural custom is being handed down. The result of the study is as follows. As a result of studying state-designated folk villages 6 sites, the custom is being handed down in a few limited gardens including Asan Oeam Village and Seongju Hangae Village. In case of Oeam Village, there are three gardens where Musa basjoo was planted including Seolimbang, Vice Minister's Residence, and Geonjae House where Musa basjoo withered now. In case of Hangae Village, it was found in Bukbi House, Hahoe Residence and Gyoridaek Jinsa's Residence and most of them were planted in front of guesthouses and main building with the assemble-planting method. Musa basjoo planting was confirmed in 39 traditional temples and it was found that Yangsan Tongdosa Temple and attached hermitage Geukrakam are currently prevalent in Musa basjoo planting. Musa basjoo was planted on either side of the stairs of Buddhist sanctums for Buddha and Avalokitesvara Guan Yin of main temples and gwaneum temples with the assemble-planting method and it has a tendency of pair planting. Considering that Musa basjoo is a southern plant, most of Musa basjoo planting was distributed around Jeollanam-do and Gyeongsangnam-do, which is closely related to the isotherm distribution of the Korean Peninsula. Especially, it was found that planting flora was centered on $12^{\circ}C$ of Warmth Index $100^{\circ}$ and annual average temperature.