• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.1
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• pp.47-56
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• 2015

Under the conditions of invested actual changes of heeling angles during MV Sewol's sinking, this study proposes passengers' evacuation scenarios, which are based on the assumption of normal orders of evacuation being given to the passengers, and evaluates using a marine-specialized human evacuation simulation tool. As results, when the heeling angle is set as 0 degree or 30 degree, it is found out that almost every passengers can success to evacuate to the musterstations, even though the evacuation times are different depending on the scenarios and the walking speeds. Meanwhile, when the heeling angle is varied as the Sewol incident, 3.1 %(Scenario Sc-Va which set chutes on port side as evacuation routes), 11.1 %(Sc-Vb, every open decks of port side as evacuation routes) and 20.0 %(Sc-Vc, every open decks of port and AFT sides as evacuation routes) among 476 passengers can successfully reach to the musterstations from their cabins with the condition of average walking speed as 2.04 m/s on flat. And only 0.8 %(Sc-Va), 3.8 %(Sc-Vb) and 10.7 %(Sc-Vc) can success to evacuate with the condition of average walking speed as 1.48 m/s on flat.

• Journal of Cadastre & Land InformatiX
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• v.53 no.2
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• pp.53-66
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• 2023

Recently, there has been a significant interest in the development of autonomous driving simulation environment based on digital twin. In the development of such digital twin-based simulation environment, many researches has been conducted not only performance and functionality validation of autonomous driving, but also generation of virtual training data for deep learning. However, such digital twin-based autonomous driving simulation system has the problem of requiring a significant amount of time and cost for the system development and the data construction. Therefore, in this research, we aim to propose a method for rapidly designing and implementing a digital twin-based autonomous driving simulation system, using only the existing 3D models and high-definition map. Specifically, we propose a method for integrating 3D model of FBX and NGII HD Map for the Busan EDC area into CARLA, and a method for adding and modifying CARLA functions. The results of this research show that it is possible to rapidly design and implement the simulation system at a low cost by using the existing 3D models and NGII HD map. Also, the results show that our system can support various functions such as simulation scenario configuration, user-defined driving, and real-time simulation of traffic light states. We expect that usability of the system will be significantly improved when it is applied to broader geographical area in the future.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.2
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• pp.114-128
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• 2013

Rapid industrialization and economic growth have led to serious problems including reduced open space, environmental degradation, traffic congestion, and urban sprawl. These problems have been exacerbated by the absence of effective conservation and governance, and have resulted in various social conflicts. In response to these challenges, many scholar and government hope to achieve sustainable development through the establishment and management of environment-friendly planning. For this purpose, we would like to analyze functional change for ecosystem by future land-use/cover changes in South Korea. Toward this goal, we predicted land-use/cover changes from 2010 to 2060 using the future population of Statistics Korea and urban growth probability map created by logistic regression analysis and analyzed ecosystem service value using costanza's coefficient. In the case of scenario 1, ecosystem service value represented 6,783~7,092 million USD. In the case of scenario 2, ecosystem represented 6,775~7,089 million USD, 2.9~7.6 million USD decreased compared by scenario 1. This was the result of area reduction for farmland and wetland which have high environmental value relatively according to urban growth by development point of view. The results of this analysis indicate that environmentally sustainable systems and urban development must be applied to achieve sustainable development and environmental protection. Quantitative analysis of environmental values in accordance with environmental policy can help inform the decisions of policy makers and urban developers. Furthermore, forecasting urban growth based on future demand will provide more precise predictive analysis.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.2
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• pp.75-85
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• 2007

There are many embedded systems which store and play multimedia streams on optical media such as recordable cd and dvd. Some of those are PVRs, DVRs, and camcorders. In this paper we describe the design and implementation of a new, well structured, fully documented, operating system independent and open source optical media API which can be used in various applications and embedded systems. We also design an ISO-9660 compliant optical media layout, an API set and the scenario for real-time recording. To prove the usability, we develop a text application to replace well-known CD-burning software, cdrecord, and a graphic burning application. All the implementations are firstly done on Linux PC environment, and then ported to a commercial embedded system which uses pSOS as an operating system.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.19-27
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• 2017

In recent years, ground subsidence has been frequently occurred by underground cavities due to the excessive groundwater inflow, caused by poor construction and management, during tunnel excavation and underground structure construction. In this study, a numerical model (SEEFLOW3D) was developed to estimate groundwater fluctuations for saturated-unsaturated poros media, evaluates the impact on ground excavation with open cut and non-open cut scenarios. In addition, the visual MODFLOW was applied to demonstrate the verification of the model compared with both results. Our results indicated that the RMSE and NRMSE was obtained to range over -3.95~5.7% and 0.56~4.62%, respectively. The developed model was expected to estimate groundwater discharges and apply analysis tool for optimum design of waterproof wall in future.

• Nuclear Engineering and Technology
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• v.45 no.7
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• pp.871-894
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• 2013

KAERI (Korea Atomic Energy Research Institute) has been operating an integral effect test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), for transient and accident simulations of advanced pressurized water reactors (PWRs). Using ATLAS, a high-quality integral effect test database has been established for major design basis accidents of the APR1400 plant. A Domestic Standard Problem (DSP) exercise using the ATLAS database was promoted to transfer the database to domestic nuclear industries and contribute to improving a safety analysis methodology for PWRs. This $2^{nd}$ ATLAS DSP (DSP-02) exercise aims at an effective utilization of an integral effect database obtained from ATLAS, the establishment of a cooperation framework among the domestic nuclear industry, a better understanding of the thermal hydraulic phenomena, and an investigation into the possible limitation of the existing best-estimate safety analysis codes. A small break loss of coolant accident with a 6-inch break at the cold leg was determined as a target scenario by considering its technical importance and by incorporating interests from participants. This DSP exercise was performed in an open calculation environment where the integral effect test data was open to participants prior to the code calculations. This paper includes major information of the DSP-02 exercise as well as comparison results between the calculations and the experimental data.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.29-35
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• 2023

In this paper, we propose a SW-EDU bot, a chatbot learning model for coding education by using a chatbot system. The same scenario-based models are created on the basis of Dialogflow and Kakao i Open Builder, which are representative chatbot builders. And then a SW-EDU bot is designed and implemented by selecting the builder more appropriate to our purpose. The implemented chatbot system aims to learn effective learning methods while encouraging self-direction of users by providing learning type selection, concept learning, and problem solving by difficulty level. In order to compare the usability of chatbot builders, five indicators are selected, and based on these, a builder with a comparative advantage is selected, and SW-EDU bot is implemented based on these. Through usability evaluation, we analyze the feasibility of SW-EDU bot as a learning support tool and confirm the possibility of using it as a new coding education learning tool.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.278-287
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• 2022

With the development of technology, driving simulators have been used in various ways. In driving simulator experiments, scenario creation is essential to increase fidelity, achieve research aims, and provide an immersive experience to the driver. However, challenges remain when creating realistic scenarios, such as developing a database and the execution of scenarios in real-time. Therefore, to create realistic scenarios, it is necessary to acquire real-time data. This study intends to develop a method of acquiring real-time weather and traffic speed information for actual, specific roads. To this end, this study suggests the concatenator for dynamic data obtained from Arduino sensors and public open APIs. Field tests are then performed on actual roads to evaluate the performance of the proposed solution. Such results may give meaningful information for driving simulator studies and for creating realistic scenarios.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.160-170
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• 2022

COVID pandemic has reshaped the world as it has been known to us and the education system is one of the most affected by it. Due to social distancing, quarantines and isolations have made it impossible for the knowledge transition to the masses using conventional methods. For cope with pandemic, the only other way available for some of the fortunate countries is the use of E-learning having somewhat the same traditional teaching method. This paper is concerned with the study of the preparedness of the learning system in some Sudanese universities due to the impact of the COVID-19 pandemic. Critical analysis has been performed to evaluate the current developing scenario, usage of the facilities available in open-source platforms, and the interaction of the universities folks with e-learning systems. The impact of such measures has been thoroughly investigated in this paper for Sudan which is already deprived of a proper education system. The investigation shows that the interact of the staff and the students with the system was acceptable where more than 85% of those enrolled to the system were interact properly and efficiently. The lecturers conducted through the platform were attended with more than 75% of the students. We also found that most of the lecturer were avoid to exam students by utilize the platform; where only 45% of the uploaded courses were conducted exams over Moodle platform. As Moodle is an open source and still need to be improved to be used for high examination credibility.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4195-4208
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• 2022

In this study, operator habitability was numerically evaluated in the event of a fire at the main control bench board (MCB) in a reference main control room (MCR). It was investigated if evacuation variables including hot gas layer temperature (HGLT), heat flux (HF), and optical density (OD) at 1.8 m from the MCR floor exceed the reference evacuation criteria provided in NUREG/CR-6850. For a fire model validation, the simulation results of the reference MCR were compared with existing experimental results on the same reference MCR. In the simulation, various input parameters were applied to the MCB panel fire scenario: MCR height, peak heat release rate (HRR) of a panel, number of panels where fire propagation occurs, fire propagation time, door open/close conditions, and mechanical ventilation operation. A specialized-average HRR (SAHRR) concept was newly devised to comprehensively investigate how the various input parameters affect the operator's habitability. Peak values of the evacuation variables normalized by evacuation criteria of NUREG/CR-6850 were well-correlated as the power function of the SAHRR for the various input parameters. In addition, the evacuation time map was newly utilized to investigate how the evacuation time for different SAHRR was affected by changing the various input parameters. In the previous studies, it was found that the OD is the most dominant variable to determine the MCR evacuation time. In this study, however, the evacuation time map showed that the HF is the most dominant factor at the condition of without-mechanical ventilation for the MCR with a partially-open false ceiling, but the OD is the most dominant factor for all the other conditions. Therefore, the method using the SAHRR and the evacuation time map was very useful to effectively and comprehensively evaluate the operator habitability for the various input parameters in the event of MCB fires for the reference MCR.