• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.215-226
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• 2015

In this study, with variables the cross section area ($97m^2$, $58m^2$, $38m^2$) and the wind velocity(0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 m/s), the time of getting off train dependent on the way of itself and the width of the evacuation route was analyzed, and also fire and evacuation characteristics is reviewed by cross section area of each wind velocity. As the result, if cross section become smaller, the density of harmful gases in the tunnel increased more than the ratio of decreasing cross section area. In the case of small cross sectional area, the surrounding environment from initial fire is indicated to exceed the limit criteria suggested in performance based design. In the analysis of effective evacuation time for evacuation characteristics, the effective evacuation time was the shortest in the case of evaluating effective evacuation time by the visibility. Also, there was significant difference between the effective evacuation time on the basis of performance based evaluation and the effective evacuation time obtained by analyzing FED (Fractional effective dose), one of the analysis method obtaining the point that deaths occur, against harmful gases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.437-446
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• 2017

70 percent of Korea's territory is covered with mountains, whose difficult conditions can cause damage to facilities. Recently, the demand for facilities related to outdoor activities including monorails has been on the rise, and such facilities are much more likely to become damaged. For this reason, a monitoring system applying IoT to mountainous areas was developed and its applicability is evaluated in this study. The current status of the existing mountainous facilities and monitoring systems were reviewed, and the current wired monitoring technology was analyzed. A scenario for IoT-based monitoring was developed, and then sensor nodes were developed, which include an RF-communication module and interface, power-supply and solar-cell. A testbed was set up at K University. The same data was collected by the wireless system as had been collected by the wired one. The study findings are as follows. Firstly, by using the wireless system, it is estimated that the construction duration can be reduced by about 25 percent, while the construction costs can be reduced by about 3~52 percent. Secondly, the safety of the construction workers can be improved by making the working conditions less dangerous, such as by eliminating the need to transport cables.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.12
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• pp.491-498
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• 2019

Digital twin is a technology that virtualizes physical objects of the real world on a computer. It is used by collecting sensor data through IoT, and using the collected data to connect physical objects and virtual objects in both directions. It has an advantage of minimizing risk by tuning an operation of virtual model through simulation and responding to varying environment by exploiting experiments in advance. Recently, artificial intelligence and machine learning technologies have been attracting attention, so that tendency to virtualize a behavior of physical objects, observe virtual models, and apply various scenarios is increasing. In particular, recognition of each robot's motion is needed to build digital twin for co-robot which is a heart of industry 4.0 factory automation. Compared with modeling based research for recognizing motion of co-robot, there are few attempts to predict motion based on sensor data. Therefore, in this paper, an experimental environment for collecting current and inertia data in co-robot to detect the motion of the robot is built, and a motion prediction model based on the collected sensor data is proposed. The proposed method classifies the co-robot's motion commands into 9 types based on joint position and uses current and inertial sensor values to predict them by accumulated learning. The data used for accumulating learning is the sensor values that are collected when the co-robot operates with margin in input parameters of the motion commands. Through this, the model is constructed to predict not only the nine movements along the same path but also the movements along the similar path. As a result of learning using SVM, the accuracy, precision, and recall factors of the model were evaluated as 97% on average.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.32-46
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• 2013

Because of short length between interchanges, traffic congestion has been caused by a lot of short trip traffic in the urban section of interregional expressway. Also, in case of expressway with Bus Only Lane, bus causes dangerous situation by conflicting between vehicles and buses in order to access from Bus Only Lane to IC. Therefore, this study aims to propose Express Lane applied by Bus Only Lane as a new lane operation in order to efficiently operate and to analyze the effectiveness on constructing Express Lane to the Pangyo-Hannam section in Gyeongbu Expressway. The study analyzes effectiveness by scenario using the micro traffic simulation tool, VISSIM 5.4. For this, the indicators which evaluate construction effect of Express Lane, are used by average delay time, average speed and total travel time. The results of the study showed the best effectiveness when Express Lane installed one, and it represented an ideal traffic condition when long distance trip traffic of the whole traffic is 25% in the study section. Therefore, the construction of Express Lane using Bus Only Lane achieves positive effectiveness on safety and expense aspect as well as uncongested flow.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.106-119
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• 2016

Flood risk map, flood damage map, disaster information map, inundation trace map are involved with the cartographic analysis of flood inundation based on prevention, preparation, restoration, response from natural disasters such as flood, flooding, etc. In this study, the analysis for channel and basin characteristics Chungju dam to Paldang dam of South han river after four river project. Flood scenario is selected to take advantage of design flood level of schematic design for river. Flood inundation of one dimensional non-uniform flow by using HEC-RAS with basin characteristics is accomplished and two dimensional unsteady flow was interpreted by using FLUMEN. Frequency analysis is carried out about each abundance of South han river for 100 year period, 200 year period and 500 year period. Flooding disaster area of 100 year period on 0.5m damage functions is 2378.8ha, 200 year period on 0.5m damage functions is 3155.2ha, 500 year period on 0.5m damage functions is 3995.3ha respectively. It will be significant data for decision making to establish inundation trace map for providing basic plan for river maintenance, land use plan, flood protection plan, application plan and getting information of flood expectation area.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.13-20
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• 2011

In this paper, we proposed a system to raise gas safety management by using the wireless communication module and intelligent gas safety appliances. Our designed systems configure a micom-gas meter, an automatic extinguisher, sensors, and a wallpad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks gas(combustible) leaks and temperature of $100^{\circ}C$ and $130^{\circ}C$. Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals for smoke and CO when occurring gas risk. Gas safety appliances and sensors takes safety measures, and transmit those signal to a wallpad. The wallpad again transmit signal like events to a control server. Users can connect web pages for gas safety through B-ISDN and control and manage them. We hereby devised scenarios for gas safety and risk management, and demonstrated their effectiveness through experiments.

• Journal of Korean Society of Transportation
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• v.29 no.2
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• pp.37-45
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• 2011

The main objective of this study is two-fold: 1) to analyze the effect of PG technology application on road user's satisfaction and driving speed, and 2) to investigate the relationship between driver's subjective workload level and their reactions related to the PG technology application. Based on the result of field observation, the experimental scenario for driving simulation study was prepared. The experimental results showed that drivers were more satisfied to the road condition with PG technology applied, and even the pattern of speed reduction was more stable than control condition. The pattern of speed reduction along driver's subjective driving workload level were slightly different by physical road condition, and road user's satisfaction was revealed to be negatively correlated with their subjective driving workload level. This result indicates that depending on situation and driver characteristic, information for the drivers could be nothing more than nuisance that just distracts drivers. In order to facilitate the implementation of PG technology in Korea, further study on related human factors, especially for those who are weak in traffic situations, is recommended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.760-767
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• 2020

Sustainable growth of hydroelectric power plants is expected in consideration of climate change and energy security. However, hydroelectric power plants always have a risk of water hammer damage, and safety assurance is very important. The water hammer phenomenon commonly occurs during operations such as rapid opening and closing of the valves and pump/turbine shutdown in pipe systems, which is more common in cases of emergency shutdown. In this study, a computational numerical model was developed using the MOC-FDM scheme to reflect the mechanism of water hammer occurrence. The proposed model was implemented in boundary conditions such as reservoir, pipeline, valve, and pump/turbine conditions and then applied to simulate hypothetical case studies. The analysis results of the model were verified using the analysis results at the main points of the pipe systems. The model produced reasonably good performance and was validated by comparison with the results of the SIMSEN package model. The model could be used as an efficient tool for the safety assessment of hydroelectric power plants based on accurate prediction of transient behavior in the operation of hydropower facilities.

• Journal of Korea Water Resources Association
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• v.47 no.12
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• pp.1145-1154
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• 2014

In recent years, as frequency and intensity of severe weather disasters such as flash flood have been increasing, providing accurate and prompt information to the public is very important and needs of user-friendly monitoring/warning system are growing. This paper introduces a method that re-produces radar observations as multimedia contents and applies reproduced data to mesh-up services. In addition, a accurate GIS matching technique to help to track the exact location going on serious atmospheric phenomena is presented. The proposed method create multimedia contents having structures such as two dimensional images, vector graphics or three dimensional volume data by re-producing various radar variables obtained from a weather radar. After then, the multimedia formatted weather radar data are matched with various detailed raster or vector GIS map platform. Results of simulation test with various scenarios indicate that the display system based on the proposed method can support for users to figure out easily and intuitively routes and degrees of risk of severe weather. We expect that this technique can also help for emergency manager to interpret radar observations properly and to forecast meteorological disasters more effectively.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.501-510
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• 2014

Volcanic eruptions alone may lead to serious natural disasters, but the associated release of water from a caldera lake may be equally damaging. There is both historical and geological evidence of the past eruptions of Mt. Baekdusan, and the volcano, which has not erupted for over 100 years, has recently shown signs of reawakening. Action is required if we are to limit the social, political, cultural, and economic damage of any future eruption. This study aims to identify the area that would be inundated following a volcanic flood from the Cheon-Ji caldera lake that lies within Mt. Baekdusan. A scenario-based numerical analysis was performed to generate a flood hydrograph, and the parameters required were selected following a consideration of historical records from other volcanoes. The amount of water at the outer rim as a function of time was used as an upper boundary condition for the downstream routing process for a period of 10 days. Data from the USGS were used to generate a DEM with a resolution of 100 m, and remotely sensed satellite data from the moderate-resolution imaging spectroradiometer (MODIS) were used to show land cover and use. The simulation was generated using the software FLO-2D and was superposed on the remotely sensed map. The results show that the inundation area would cover about 80% of the urban area near Erdaobaihezhen assuming a 10 m/hr collapse rate, and 98% of the area would be flooded assuming a 100 m/hr collapse rate.