• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.25-36
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• 2021

This study analyzed the causes of flood accidents, such as isolation and lost footing accidents in Dorimcheon, to provide legal and institutional improvements. For cause analysis, Field Investigation, Stakeholder Interview, Report, manual, Law et al. Review, Analysis of water level change characteristics, automatic alarm issuance standard level analysis, and evacuation time according to river control were evaluated. Dorimcheon has the characteristics of a typical urban river, which is disadvantageous in terms of water control. In addition, the risk of flood accidents is high because the section where fatal accidents occur forms sharply curved channels. Tripping and isolation accidents occur in the floodplain watch and evacuation stage, which is the stage before the flood watch and warning is issued. Because floodplain evacuation is issued only when the water level rises to the floodplain, an immediate response according to the rainfall forecast is essential. Furthermore, considering that the rate of water level rise is up to 2.62 cm/min in Sillimgyo 3 and Gwanakdorimgyo, sufficient evacuation time is not secured after the floodplain watch is issued. Considering that fatal accidents occurred 0.46 m below the standard water level for the flood watch, complete control is very important, such as blocking the entry of rivers to prevent accidents. Based on these results, four improvement measures were suggested, and it is expected to contribute to the prevention of Tripping and Isolation Accidents occurring in rivers.

• Korean Journal of Heritage: History & Science
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• v.45 no.1
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• pp.218-231
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• 2012

A total of 126 fossil scaphopods (121 specimens from the Hagjeon Formation and 5 specimens from the Duho Formation) were found from the Cenozoic strata, Hagjeon and Duho Formations, Pohang Basin, Korea. Five species belonging two genera (Fissidentalium yokoyamai, F. sp. A, B, and Rhabdus sp. A, B) were classified: the most dominant species is Fissidentalium yokoyamai. The species of Fissidentalium yokoyamai is characterized by curved shell (accuration=3.90%) and very closely spaced longitudinal ribs on shell surfaces, while the species of Rhabdus is a nearly straight shell characterized by concentric growth lines without longitudinal ribs. Identification of two genera is somewhat easy due to such morphological differences but classification at generic level is hard because diagnostic features (e.g., cross section and apical structure) are lost in the most specimens. Consequently, except for Fissidentalium yokoyamai, the rest were classified temporarily as F. sp. A, B, and Rhabdus sp. A, B. Two types of preservation state were recognized: one is three-dimensionally preserved specimen (3D specimen) and the other is compressed specimen. Internal parts of the 3D specimen is filled with clastic sediments identical to the surrounding sediments of the shells, which is not observed in the compressed specimens. It is, thus, concluded that the 3D fossils were originally empty but internal cavity were immediately filled with the sediments, which may have protect from the compaction due to pressure during deposition of the gravelly to coarse sandstone of the Hagjeon Formation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.2
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• pp.105-116
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• 2023

The fatality rate of secondary accidents is seven times that of general traffic accidents. If limited to highways, one in four deaths are said to occur from secondary accidents. Unexpected situations which do not give drivers time to prepare are the cause of secondary accidents. This risk results in more fatalities on highways with high driving speeds. Existing studies have conducted research on traffic accidents and on secondary traffic accidents that occur after a primary traffic accident, without considering unexpected situations that may occur on the road. Therefore, to reduce damage and casualties caused by secondary accidents, there is a need to create a safe road environment by removing the possibility of causing accidents. This study analyzes whether the day of occurrence, time of occurrence, and radius of the curve of an unexpected situation are related to the occurrence of an unexpected situation. This study was based on data of accidents that occurred in 2022 on the Cheonan-Nonsan Expressway and the Seoul-Yangyang Expressway. The radius of the curve was calculated by dividing the section of the highway into straight, clothoid, and curved sections through cluster analysis. Results of the analysis indicate that the day and time of occurrence and the curve radius are associated with unexpected situations.

• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.119-128
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• 2022

This study analyzes the effects of the number of angles and bends on resistance in a conductor-embroidered stitch circuit for efficient power transfer through a conductor of wearable energy harvesting to study changes in power lost through connection with actual solar panels. In this study, the angle of the conductive stitch circuit was designed in units of 30˚, from 30˚ to 180˚, and the resistance was measured using an analog Discovery 2 device. The measured resistance value was analyzed, and in the section of the angle where the resistance value rapidly changes, it was measured again and analyzed in units of 5˚. Following this, from the results of the analysis, the angle at which the tension was applied to the stitch converges was analyzed, and the resistance was measured again by varying the number of bends of the stitch at the given angle. The resistance decreases as the angle of the stitch decreases and the number of bends increases, and the conductor embroidery stitch can reduce the loss of power by 1.61 times relative to general embroidery. These results suggest that the stitching of embroidery has a significant effect on the power transfer in the transmission through the conductors of wearable energy harvesting. These results indicate the need for a follow-up study to develop a conductor circuit design technology that compares and analyzes various types of stitches, such as curved stitches, and the number of conductors, so that wearable energy harvesting can be more efficiently produced and stored.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4D
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• pp.395-402
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• 2010

The seriousness of a traffic accident appears relatively higher on the curve sections compared with the straight sections due to a change in speed caused by a change in the driver's sight. In particular, the visual distortion phenomenon, one of the dangerous factors taking place on the curve sections, appears different according to the road's geometric design. Although it is a genuinely principal design factor which should be necessarily considered in designing a road, the previous researches on establishing the design standards for it have been insufficiently conducted. As a result, the establishment of the road design standards for the curve sections considering the sight distortion phenomenon is desperately required. This research examined the previous researches on the driver's behaviors, the driver's sight characteristics and the perceived curve radius on the curve sections, and developed the theoretical model of perceived curve radius to which a mathematical technique is applied in consideration of the visual distortion phenomenon on the two-lane curve sections in a local area. In addition, after the theoretical visual distortion was calculated on the basis of the theoretical model of perceived curve radius, the range of error on the theoretical recognition radius model formula was verified through comparing it with the previous researches' experiential visual distortion level and analyzing both of them. As a result, it was observed that as the curve radius practically increases in the theoretical recognition curve radius, the range of error tends to go down, which reflects well the characteristics of the curve sections on the road. Based on this research, it is expected that this research will be helpful to eliminate the safety defects when designing the curve sections and contribute to develop the road design standards considering human factors in the future.

• Korean Journal of Plant Resources
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• v.37 no.1
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• pp.22-34
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• 2024

Recently, in several regions of Korea, we discovered the occurrence of Sagina micropetala Rauschert and S. procumbens L. All the plants of the genus Sagina growing in Korea are 5-merous and belong to the sect. Spergella. However, the two taxa we discovered belong to the sect. Saginella and are 4-merous. In addition, morphological characteristics such as sepals during the fruiting season and seeds were significantly different from those of species of the genus Sagina that occur in Korea. To clearly identify these species, we compared and observed their primary morphological characteristics using illustrated books and literature. Morphologically, S. micropetala exhibits the following traits: pubescence along the leaf margin, horizontally spreading sepals with red margins, and convex protrusions on the seed surface. In contrast, S. procumbens can be distinguished by its pedicels, which are curved during the flowering season and erect during the fruiting season. This plant also has broadly ovate sepals with white or yellowish-green margins, and flat seed surface protrusions. In terms of molecular analyses, 19 samples of Sagina were divided into two clades (S. micropetala and S. procumbens), confirming the taxonomic identity of the Sagina spp.

• Explosives and Blasting
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• v.30 no.2
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• pp.29-42
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• 2012

Variables influencing the free face movement due to rock blasting include the physical and mechanical properties, in particular the discontinuity characteristics, explosive type, charge weight, burden, blast-hole spacing, delay time between blast-holes or rows, stemming conditions. These variables also affects the blast vibration, air blast and size of fragmentation. For the design of surface blasting, the priority is given to the safety of nearby buildings. Therefore, blast vibration has to be controlled by analyzing the free face movement at the surface blasting sites and also blasting operation needs to be optimized to improve the fragmentation size. High-speed digital image analysis enables the analyses of the initial movement of free face of rock, stemming optimality, fragment trajectory, face movement direction and velocity as well as the optimal detonator initiation system. Even though The high-speed image analysis technique has been widely used in foreign countries, its applications can hardly be found in Korea. This thesis aims at carrying out a fundamental study for optimizing the blast design and evaluation using the high-speed digital image analysis. A series of experimentation were performed at two large surface blasting sites with the rock type of shale and granite, respectively. Emulsion and ANFO were the explosives used for the study. Based on the digital images analysis, displacement and velocity of the free face were scrutinized along with the analysis fragment size distribution. In addition, AUTODYN, 2-D FEM model, was applied to simulate detonation pressure, detonation velocity, response time for the initiation of the free face movement and face movement shape. The result show that regardless of the rock type, due to the displacement and the movement velocity have the maximum near the center of charged section the free face becomes curved like a bow. Compared with ANFO, the cases with Emulsion result in larger detonation pressure and velocity and faster reaction for the displacement initiation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3894-3906
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• 2014

The aim of this study was to classify the central Buddhist temple among the state-designated cultural assets, which were measured precisely, into the gable roof buildings and the gambrel roof buildings to analyze the Ang-Goak, Inside waist, ridge ratio, and roof inclination represented on the roof, and prepare basic objective material for the restoration and repair of cultural assets. As a result, as for the relationship between the roof curve and the inclination of the gable roof building and gambrel roof building, the following conclusions could be drawn. First, the Ang-Goak and Inside waist of the gable roof building had a close correlation with the building size, and the internal high pillar existence. In addition, the Ang-Goak and Inside waist were shown in the 7-ryangga structure, which is greater in size than in the 5-ryangga structure. This was found to be related to the building size. Second, the Ang-Goak and Inside waist of the gable roof building has a correlation with each other, and it was found that Inside waist also was large in the building with a larger Ang-Goak. The roof inclination rarely had a connection with variable factors (plane factor, elevation factor, and cross section factor). The sizes of Ang-Goak, Inside waist, and ridge ratio were similar in the outside 1 chulmok and outside 2 chulmok of gongpo but those sizes were relatively larger in outside 3 chulmok. Third, the Ang-Goak and Inside waist of the gambrel roof building moved independently for each building without a correlation with each other, unlike the case of the gable roof building. The front and the side showed a correlation with each other, and in the building with the large curve of the front side, the curve was also large in the sides. Fourth, in the case of the building with a high pillar inside the gambrel roof building, the Ang-Goak and Inside waist were larger. On the other hand, they were smaller in the case of a building without a high pillar. This was found to have a close relationship with the building size. In addition, the ridge ratio has a close connection with the building size and building height. Therefore, the ridge ratio is larger in a high building or large sized building. The roof inclination rarely has a correlation with variable factors, as in the case of the gable roof building.

• MISULJARYO - National Museum of Korea Art Journal
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• v.99
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• pp.50-71
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• 2021

The Five-story Stone Pagoda from the Dongsa-ri Temple Site in Buyeo, dated to early Goyeo Dynasty, is valuable in that it is the southernmost example of the capital Kaesong pagoda style. This pagoda exhibits characteristics of the central Goryeo style featured in the pagodas built in and around the capital Kaesong, such as the diagonally curved section of the support for the cover stone above the upper stereobate. It also shares stylistic affinities with eleventh-century stone pagodas. The ansangmun (elephant eye patterns) in the lower stereobate of the Dongsa-ri Five-story Stone Pagoda resemble those in the pedestal of the Stone Seated Buddha (which was likely repaired in 1028 during the reign of King Hyeonjong), at the Jeongrimsa Temple site in Buyeo. It also reflects elements found in the flagpole supports from the Cheonheungsa Temple site in Cheonan. The sculpting techniques used in these patterns are also similar. Such congruencies suggest that the Dongsa-ri Five-story Stone Pagoda was built in the eleventh century. The Dongsa-ri Temple Site in Buyeo, located near the Geumgang River, served as a principal route for transporting grain-tax during the Goryeo Dynasty. It was also situated along the way to the Goryeo royal temple, Gaetaesa Temple. The geographical significance of the site and the extensive repairs undertaken at Jeongrimsa Temple during the reign of King Hyeonjong (r. 1009-1031) of the Goryeo Dynasty appear to have impacted the production of the Dongsa-ri Five-story Stone Pagoda. The Dongsa-ri Five-story Stone Pagoda also bears stylistic resemblances to the stone pagoda and flagpole supports found at neighboring Cheonheungsa Temple, which is presumed to be related to the establishment of Honggyeongsa (or Honggyeongwon) Temple in 1021 in Cheonan. This indicates the route of the transmission of the Kaesong pagoda style. The Five-story Stone Pagoda from the Dongsa-ri Temple Site pays testimony to the cultural accomplishments of eleventh-century stone artworks in Buyeo and adjacent regions. This pagoda embodies the majestic and assertive aesthetics that define of the Goryeo Dynasty, as do early Goryeo colossal Buddhist sculptures, including the Stone Standing Maitreya Bodhisattva at Daejosa Temple in Buyeo, the Stone Standing Buddha Triad at Gaetaesa Temple in Nonsan, and the Stone Standing Maitreya Bodhisattva at Gwanchoksa Temple in Nonsan. All of these bear similarities to the massive stone lantern and pagoda at Hyeonhwasa Temple in the capital Kaesong. The production of the light, sleek, sharp, and sophisticated Dongsa-ri Five-story Stone Pagoda is presumed to reflect the maturity of the cultural competence of the people in Dongsa-ri, Buyeo under the influence of Buddhist culture from the capital Kaesong during the eleventh century, a time marked by active cultural exchanges among regions.

• The Journal of the Petrological Society of Korea
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• v.27 no.3
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• pp.109-120
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• 2018

The distributional characteristics of fault segments in Cretaceous and Tertiary rocks from southeastern Gyeongsang Basin were derived. The 267 sets of fault segments showing linear type were extracted from the curved fault lines delineated on the regional geological map. First, the directional angle(${\theta}$)-length(L) chart for the whole fault segments was made. From the related chart, the general d istribution pattern of fault segments was derived. The distribution curve in the chart was divided into four sections according to its overall shape. NNE, NNW and WNW directions, corresponding to the peaks of the above sections, indicate those of the Yangsan, Ulsan and Gaeum fault systems. The fault segment population show near symmetrical distribution with respect to $N19^{\circ}E$ direction corresponding to the maximum peak. Second, the directional angle-frequency(N), mean length(Lm), total length(Lt) and density(${\rho}$) chart was made. From the related chart, whole domain of the above chart was divided into 19 domains in terms of the phases of the distribution curve. The directions corresponding to the peaks of the above domains suggest the directions of representative stresses acted on rock body. Third, the length-cumulative frequency graphs for the 18 sub-populations were made. From the related chart, the value of exponent(${\lambda}$) increase in the clockwise direction($N10{\sim}20^{\circ}E{\rightarrow}N50{\sim}60^{\circ}E$) and counterclockwise direction ($N10{\sim}20^{\circ}W{\rightarrow}N50{\sim}60^{\circ}W$). On the other hand, the width of distribution of lengths and mean length decrease. The chart for the above sub-populations having mutually different evolution characteristics, reveals a cross section of evolutionary process. Fourth, the general distribution chart for the 18 graphs was made. From the related chart, the above graphs were classified into five groups(A~E) according to the distribution area. The lengths of fault segments increase in order of group E ($N80{\sim}90^{\circ}E{\cdot}N70{\sim}80^{\circ}E{\cdot}N80{\sim}90^{\circ}W{\cdot}N50{\sim}60^{\circ}W{\cdot}N30{\sim}40^{\circ}W{\cdot}N40{\sim}50^{\circ}W$) < D ($N70{\sim}80^{\circ}W{\cdot}N60{\sim}70^{\circ}W{\cdot}N60{\sim}70^{\circ}E{\cdot}N50{\sim}60^{\circ}E{\cdot}N40{\sim}50^{\circ}E{\cdot}N0{\sim}10^{\circ}W$) < C ($N20{\sim}30^{\circ}W{\cdot}N10{\sim}20^{\circ}W$) < B ($N0{\sim}10^{\circ}E{\cdot}N30{\sim}40^{\circ}E$) < A ($N20{\sim}30^{\circ}E{\cdot}N10{\sim}20^{\circ}E$). Especially the forms of graph gradually transition from a uniform distribution to an exponential one. Lastly, the values of the six parameters for fault-segment length were divided into five groups. Among the six parameters, mean length and length of the longest fault segment decrease in the order of group III ($N10^{\circ}W{\sim}N20^{\circ}E$) > IV ($N20{\sim}60^{\circ}E$) > II ($N10{\sim}60^{\circ}W$) > I ($N60{\sim}90^{\circ}W$) > V ($N60{\sim}90^{\circ}E$). Frequency, longest length, total length, mean length and density of fault segments, belonging to group V, show the lowest values. The above order of arrangement among five groups suggests the interrelationship with the relative formation ages of fault segments.