• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.4
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• pp.1-11
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• 2014

Traffic congestion cost is more likely to occur in the inner city than interregional road, and it accounts for about 63.39% of the whole. Therefore, it is important to mitigate traffic congestion of the inner city. Traffic congestion in the urban could be divided into Recurrent congestion and Non-recurrent congestion. Quick and accurate detection of Non-recurrent congestion is also important in order to relieve traffic congestion. The existing studies about incident detection have been variously conducted, however it was limited to Uninterrupted Traffic Flow Facilities such as freeway. Moreover study of incident detection on the interrupted Traffic Flow Facilities is still inadequate due to complex geometric structure such as traffic signals and intersections. Therefore, in this study, incident detection model was constructed using by Artificial Neural Network to aim at urban arterial road that is interrupted traffic flow facility. In the result of the reliability assessment, the detection rate were 46.15% and false alarm rate were 25.00%. These results have a meaning as a result of the initial study aimed at interrupted traffic flow. Furthermore, it demonstrates the possibility that Non-recurrent congestion can be detected by using car navigation data such as car navigator system device.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.3
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• pp.110-121
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• 2021

The importance of tidal flats lost due to industrialization has recently received attention, and attention is being paid to the creation of artificial tidal flats and maintenance of natural tidal flats. However, there is still a lack of understanding about the behavioral characteristics of mud, mud, and sand that form tidal flats. Although research on the movement characteristics of mixed soils such as tidal flats has been conducted through field investigations and hydraulic experiments, interest in developing a numerical model based on these results has not yet reached. In this paper, the purpose of this paper is to establish a mixed soil model that can efficiently manage the low quality of the tidal flats. In constructing a model for reproducing the surface movement of mixed soil, the numerical stability of the reproduction and movement of sand and mud constituting the mixed soil in the numerical model should be considered first, so first, the volume of sand and mud constituting the mixed soil A mixed soil model representing the relationship was proposed based on a topographical diagram representing the geometric structure of the mixed soil. In order to consider the dry bulk density of the mixed soil, it was possible to consider the dry bulk density of the mud by introducing the water content of the mud containing water. In addition, it was confirmed that the mud and sand movement calculation according to the slope collapse of the mixed soil was stably performed through the calculation of the slope collapse of the mixed soil through the numerical analysis model to which the proposed mixed soil model was applied.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.295-306
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• 2008

The Intersection is inner traffic facilities and the space where the roads are intersected and connected. And also, the Intersection is the decision-making section for drivers to select the route according to the geometric structure and operation method. However decision-making section cause to raise car accidents rate because it imposes a heavy burden on drivers. In that reason, many countries such as Europe use the Roundabouts to reduce the numbers of decision making and collision. In Korea, the kinds of method are just introduced and it is using now but there are no exact standards. Hence, this study suggests the process to evaluate and determine the types of Intersection which are based on the traffic flow (congestion) and traffic safety (accidents). Firstly, this study presents the number of accident at each Intersection which is depended on the traffic volume. Secondly, this study calculates and analysis the accident at signalized Intersection, non-signalized Intersection and Roundabout by TSIS-NETSIM program. Thirdly, this study concludes the best suitable Intersection type through the materials which are mentioned before.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.156-168
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• 2024

Purpose: The trend of highway traffic accidents shows a repeating pattern of increase and decrease, with the fatality rate being highest on highways among all road types. Therefore, there is a need to establish improvement measures that reflect the situation within the country. Method: We conducted accident severity analysis using Random Forest on data from accidents occurring on 10 specific routes with high accident rates among national highways from 2019 to 2021. Factors influencing accident severity were identified. Result: The analysis, conducted using the SHAP package to determine the top 10 variable importance, revealed that among highway traffic accidents, the variables with a significant impact on accident severity are the age of the perpetrator being between 20 and less than 39 years, the time period being daytime (06:00-18:00), occurrence on weekends (Sat-Sun), seasons being summer and winter, violation of traffic regulations (failure to comply with safe driving), road type being a tunnel, geometric structure having a high number of lanes and a high speed limit. We identified a total of 10 independent variables that showed a positive correlation with highway traffic accident severity. Conclusion: As accidents on highways occur due to the complex interaction of various factors, predicting accidents poses significant challenges. However, utilizing the results obtained from this study, there is a need for in-depth analysis of the factors influencing the severity of highway traffic accidents. Efforts should be made to establish efficient and rational response measures based on the findings of this research.

• Journal of the Korean GEO-environmental Society
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• v.25 no.4
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• pp.21-28
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• 2024

In this study, a polyhedral domain decomposition method for Smoothed Particle Hydrodynamics (SPH) analysis is introduced. SPH which is one of meshless methods is a numerical analysis method for fluid flow simulation. It can be useful for analyzing fluidic soil or fluid-structure interaction problems. SPH is a particle-based method, where increased particle count generally improves accuracy but diminishes numerical efficiency. To enhance numerical efficiency, parallel processing algorithms are commonly employed with the Cartesian coordinate-based domain decomposition method. However, for parallel analysis of complex geometric shapes or fluidic problems under dynamic boundary conditions, the Cartesian coordinate-based domain decomposition method may not be suitable. The introduced polyhedral domain decomposition technique offers advantages in enhancing parallel efficiency in such problems. It allows partitioning into various forms of 3D polyhedral elements to better fit the problem. Physical properties of SPH particles are calculated using information from neighboring particles within the smoothing length. Methods for sharing particle information physically separable at partitioning and sharing information at cross-points where parallel efficiency might diminish are presented. Through numerical analysis examples, the proposed method's parallel efficiency approached 95% for up to 12 cores. However, as the number of cores is increased, parallel efficiency is decreased due to increased information sharing among cores.

• The Journal of the Petrological Society of Korea
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• v.27 no.3
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• pp.139-151
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• 2018

The Songgang-ri area, Cheongsong-gun, which is located in the Sobaeksan province of Yeongnam Massif near the southwestern boundary of Yeongyang subbasin of Gyeongsang Basin, consists of age unknown metamorphic rocks (banded gneiss, granitic gneiss, limesilicates) and age unknown igneous rock (granite gneiss) which intrudes them. This paper researched the geological structures of the Songgang-ri area from the geometric and kinematic features and the developing sequence of multi-deformed rock structures in the geological outcrops exposed about 170 m along the riverside of Yongjeoncheon in the eastern part of Songgang village, Songgang-ri. In the Songgang-ri geological outcrops are recognized three times (Fn, Fn+1, Fn+2) of folding, three times (Dk-I, Dk-II, Dk-III) intrusion of acidic dykes, one time of faulting, which are different in deformation and intrusion timing each other. These geological structures are at least formed by five times (Dn, Dn+1, Dn+2, Dn+3, Dn+4) of deformation. The Dn deformation is recognized by Fn fold which axial surface is parallel to the regional foliation. The Dn+1 intruded the (E)NE trending Dk-I dyke in the earlier phase and formed the NW trending Fn+1 fold in the later phase under compression of (E)NE-(W)SW direction. There are tight, isoclinal, intrafolial folds, boudinage, ${\sigma}$- or ${\delta}$-type boudins, asymmetric fold, C' shear band as the major deformed rock structures. The Dn+2 intruded the (N)NW trending Dk-II dyke in the earlier phase and formed NE trending Fn+2 fold in the later phase under compression of (N)NW-(S)SE direction. There are open fold and folded boudinage as those. The Dn+2 intruded the Dk-III dyke which cuts the Dk-I and Dk-II dykes and the axial surface of Fn+2 fold. The Dn+3 formed the left-handed reverse oblique-slip fault of NNE trend in which hanging wall moves into the SSE direction. Considering in that such five times of deformation recognized in the Songgang-ri geological outcrops are closely connected to the distribution and geological structure of the constituents in the more regional area as well as Songgang-ri area, the research result is expected to play a great data in clarifying and understanding the geological structure and its development process of the surrounding and boundary constituents of the Yeongnam Massif and Gyeongsang Basin.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.541-554
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• 2019

The Taebaeksan Zone of the Okcheon Belt is a prominent fold-thrust belt, preserving evidence for overlapped polyphase and diachronous orogenic events during crustal evolution of the Korean Peninsula. The Pyeongchang-Jeongseon area of the northwestern Taebaeksan Zone is fault-bounded on the western Jucheon and southern Yeongwol areas, showing lateral variations in stratigraphy and structural geometries. For better understanding these geological characteristics of the northwestern Taebaeksan Zone, we have studied the structural geometry of the Pyeongchang-Jeongseon area. For this, we have firstly carried out the SHRIMP U-Pb age analysis of the age-unknown sedimentary rock to clarify stratigraphy for structural interpretation. The results show the late Carboniferous to middle Permian dates, indicating that it is correlated to the Upper Paleozoic Pyeongan Supergroup. In addition to this, we interpreted the geometric relationships between structural elements from the detailed field investigation of the study area. The major structure of the northwestern Taebaeksan Zone is the regional-scale Jeongseon Great syncline, having NE-trending hinge with second-order folds such as the Jidongri and Imhari anticlines and the Nambyeongsan syncline. Based on the stereographic and down-plunge projections of the structureal elements, the structural geometry of the Jeongseon Great syncline can be interpreted as a synformal culmination, plunging slightly to the south at its southern area, and north at the northern area. The different map patterns of the northern and southern parts of the study area should be resulted in different erosion levels caused by the plunging hinges. Considering the Jeongseon Great syncline is the major structure that constrains the distribution of the Paleozoic strata of the Pyeongchang and Jeongseon areas, the symmetric repetition of the lower Paleozoic Joseon Supergroup in both limbs should be re-examined by structural mapping of the Hangmae and Hoedongri formations in the Pyeongchang and Jeongseon areas.

• The Journal of the Petrological Society of Korea
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• v.15 no.2 s.44
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• pp.49-59
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• 2006

This study clarifies the deformation history of Precambrian metamorphic rocks of Sobaegsan Massif (Wonnam Formation, Pyeonghae granite gneiss, Hada leucogranite gneiss) in Giseong-myeon area, Uljin-gun, Korea. It is based on the geometric and kinematic features and the developing sequence of multi-deformed rock structures. It also reviews the extension of Yecheon Shear Zone and the relative occurrence time of each deformation phase from previous researches. It suggests that the geological structure was formed at least through five phases of deformation after formation of their gneissosity or schistosity. (1) The first phase of deformation took placed under compression of ENE-WSW direction, forming NNW trending regional foliation and very tight isoclinal fold. The general trend of gneissosity or schistosity is inferred to be ENE before the first phase of deformation, being rearranged into NNW by the isoclinal folding. (2) The second phase of deformation formed ENE trending regional foliation and tight, isoclinal, rootless intrafolial folds under compression of NNW-SSE direction [occurrence time: after deposition (Permian age) of Dongsugok Formation, Pyeongan Croup, Janggunbong area]. (3) The third phase of deformation occurred by dextral ductile shearing on the regional foliation, forming stretching lineation of ENE trend and S-C mylonitic structure (after intrusion of Hesozoic homblende granite, Sangunmyeon area-before intrusion of Mesozoic Chunyang granite, Janggunbong area). (4) The fourth phase occurred under (E)NE-(W)SW compression, forming (N)NW trending open fold. (5) The fifth phase took place under N-S compression, forming NNE and NNW trending conjugate strike-slip faults, E-W trending thrust-slip faults, and drag folds related to these fault movements. The deformed structures of fourth and fifth phases result from tectonic movement associated with the developing of the Gyeongsang Basin in Cretaceous age, and it partially rearranged the general ENE trend of the regional foliation in the study area. It also suggests that the Yecheon Shear Zone of E-W trending extends into this area but the ductile shear deformation is weakly developed.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.151-164
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• 2022

According to the records of historical and instrumental earthquakes, the southeastern part of the Korean Peninsula is considered the highest seismic activity area. Owing to recent reports of numerous Quaternary faults along the Yangsan and Ulsan fault zones, paleoseismological studies are being actively conducted in these areas. The study area is located in the central part of the Ulsan fault zone, where the largest number of active faults have been reported. Based on lineament and geomorphic analysis using LiDAR images and aerial photographs, fault-related landforms showing topographic relief were observed and a trench survey was conducted. The trench length 20 m, width 5 m, depth 5 m is located approximately 300 m away to the northeast from the previously reported Malbang fault. From the trench section, we interpreted the geometric and kinematic characteristics of the fault based on the deformed features of the Quaternary sedimentary layers. The attitude of the reverse fault, N26°W/33°NE, is similar to those of the reported faults distributed along the Ulsan fault zone. Although a single apparent displacement of approximately 40 cm has been observed, the true displacement could not be calculated due to the absence of the slickenline on the fault plane. Based on the geochronological results of the cryogenic structure proposed in a previous study, the most recent faulting event has been estimated as being earlier than the late Wurm glaciation. We interpreted the thrust fault system of the study area as an imbrication structure based on the previous studies and the fault geometry obtained in this additional trench. Although several previous investigations including many trench surveys have been conducted, they found limited success in obtaining the information on fault parameters, which could be due to complex characteristics of the reverse fault system. Additional paleoseismic studies will contribute to solving the mentioned problems and the comprehensive fault evolution.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.870-877
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• 1998

With impedance spectrum measurements, impedance was studied in the interface between sample solutions for $K^+-ion$ selective PVC membrane electrode containing neutral carriers [dibenzo-18-crown-6 (D18Cr6) and valinomycine (Val)]. Response characteristics of electrode were examined by measuring AC impedance spectra that were resulted from the chemical structure and the content of carrier, variation of plasticizer, membrane thickness, doping of base electrolytes, and concentration variation of sample solution. Transport characteristics of PVC membrane electrode were also studied. It was found that the equivalent circuit for the membrane in $K^+$ solution could be expressed by a series combination of solution resistance and a parallel circuit consisting of the bulk resistance and geometric capacitance of the membrane system. But the charge transfer resistance and Warburg resistance were overlapped a little in the low concentration and low frequency ranges. The carrier, D18Cr6 was best for electrode and impedance characteristics, and ideal electrode characteristics were appeared especially in case of doping of the base electrolyte[potassium tetraphenylborate(TPB)]. The optimum carrier content was about 3.23 wt% in case of D18Cr6 and Val. DBP was best as a plasticizer. As membrane thickness decreased the impedance characteristics was improved, but electrode characteristics were lowered for membrane thickness below the optimum. In the case of D18Cr6, the selectivity coefficients by the mixed solution method for the $K^+$ ion were the order of $NH_4{^+}>Ca^{2+}>Mg^{2+}>Na^+$.