• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.15-22
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• 2019

Simulation methods are being studied for various service models that can be used in industries as the development of web technology. DEVS is being used as a tool to simulate through scenarios using various information. In addition, DEVS/WS integrates web-based DEVS models through a distributed computing environment and can be used as tools for high-performance computing and data distribution. This paper describes a method for simulating an intelligent transportation system in DEVS/WS environment. This paper propose dynamic interest management model(DIMM) applied the genetic algorithm, manage efficiently road information of moving node. And, this paper evaluates performance of the dynamic interest management model in comparing to the none interest management model(NIMM). The transmitted messages and simulation time of the DIMM is saved than that of the NIMM.

• Journal of Practical Engineering Education
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• v.9 no.2
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• pp.107-117
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• 2017

here are many cases that take a software education as a required course for non-major students in university curriculums. However, non-major students are experiencing various difficulties in the process of learning programming languages, and there is also the opposite opinion in terms of their effectiveness. In this study, we developed a design based software education model (DBSEM) and curriculum to solve these problems and applied it to undergraduate non-undergraduate students for the last 8 years. In the proposed method, we provide a specialized educational tool such as 'block-based programming tool', but developed 'core module' and 'concept learning module' for computational thinking and applied 'prototype design module' and coding strategy based on it. As a result, non-major undergraduates could easily learn block-based scripting tools and acquire core concepts of computational thinking.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.29-37
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• 2019

Synthetic Aperture Radar (SAR) observations are powerful tools to monitor surface's displacement very accurately, induced by earthquake, volcano, ground subsidence, glacier movement, etc. Especially, radar interferometry (InSAR) which utilizes phase information related to distance from sensor to target, can generate displacement map in line-of-sight direction with accuracy of a few cm or mm. Due to decorrelation effect, however, degradation of coherence in the InSAR application often prohibit from construction of differential interferogram. Offset tracking method is an alternative approach to make a two-dimensional displacement map using intensity information instead of the phase. However, there is limitation in that the offset tracking requires very intensive computation power and time. In this paper, efficiency of parallel computing has been investigated using high performance computer for estimation of glacier velocity. Two TanDEM-X SAR observations which were acquired on September 15, 2013 and September 26, 2013 over the Narsap Sermia in Southwestern Greenland were collected. Atotal of 56 of 2.4 GHz Intel Xeon processors(28 physical processors with hyperthreading) by operating with linux environment were utilized. The Gamma software was used for application of offset tracking by adjustment of the number of processors for the OpenMP parallel computing. The processing times of the offset tracking at the 256 by 256 pixels of window patch size at single and 56 cores are; 26,344 sec and 2,055 sec, respectively. It is impressive that the processing time could be reduced significantly about thirteen times (12.81) at the 56 cores usage. However, the parallel computing using all the processors prevent other background operations or functions. Except the offset tracking processing, optimum number of processors need to be evaluated for computing efficiency.

• Design & Manufacturing
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• v.13 no.2
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• pp.54-59
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• 2019

CNC(Computer Numerical Control) machine tools are being used in various industrial fields such as aircraft and automobiles. The machining conditions used in the mold industry are used, and the simulation and the experiment are compared. The tool used in the experiment was carried out to increase the reliability of the simulation of the cutting machining. The program used in the 3D-FEM (finite element method) was the AdvantEdge and predicted by down-milling. The tool model is used 3D-FEM simulation by using the cutting force, temperature prediction. In this study, we carried out the verification of cutting force by using a 3-axis tool dynamometer (Kistler 9257B) system when machining the plastic mold Steel machining of NAK-80. The cutting force experiment data using on the charge amplifier (5070A) is amplified, and the 3-axis cutting force data are saved as a TDMS file using the Lab-View based program using on NI-PXIe-1062Q. The machining condition 7 was the most similar to the simulation and the experimental results. The material properties of the NAK-80 material and the simulation trends reflected in the reverse design of the tool were derived similarly to the experimental results.

• Journal of IKEEE
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• v.23 no.3
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• pp.768-776
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• 2019

With the deployment of 4-th generation industrial revolution, the computer based manufacturing technologies employing advanced IT technology are much more popular than any other past years. In this research, some novel S/W technologies related to the industrial X-ray CT (computed tomography) for the inspection of the industrial parts are introduced. First, newly constructed industrial X-ray CT is presented in this paper, where some basic principles and functions of the CT are described. Then some research platforms are developed to generate more advanced functionalities of the industrial CT. Especially, the data transform from CT to general S/W such as Matlab is conducted. And based on this techniques, some supplementary S/W platform such as GUI (graphical user interface) of the CT S/W and some 3D voxel based image processing technologies can be developed in this paper. The industrial CT is one of the rare research items and it's values can be much more enhanced when it is used with advanced IT technologies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.305-310
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• 2019

Survival horror games aim to seek cathartic psychological escapism from the framed fear or hostile environment. However, if the goal of the game playing is only "survival" against hostile environment, the motivation of such environment adaptive games may not be based on the framed fear. We may call such games as "environment adaptive survival games". In this paper, we analyze the contents of six such survival games that have large user groups in Steam platform based on the pilot survey. We extract 13 almost common fun elements that induce the fun of such games. An online user survey was conducted through multiple survival game cafe to investigate who play such games. There was no gender differences in playing time but females prefer constructing tools as a fun element and play puzzle and simulation games more than males. We found that survival games could be welcomed by female users under 30 years old if 'horror' element was minimized.

• Journal of Internet Computing and Services
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• v.22 no.4
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• pp.51-63
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• 2021

Recently, virtual communication has become a standard tool due to the outbreak of COVID-19. Likewise online communication is emerging as an essential competency. In this study, we aimed to develop a comprehensive and systematic digital literacy measurement tool reflecting the changes and needs of society. Construct variables were drawn by characterizing existing digital literacy measurement tools. Thirty-four items corresponding to the concept of each variable were developed. The developed measurement tool was then evaluated in the form of surveys from university students belonging to the digital native generation, and the reliability and validity were performed through exploratory and confirmatory factor analysis. The digital literacy measurement tool contained five sub-factors and twenty-five questions. In addition, hierarchical regression analysis was performed to verify the predictive validity of digital literacy sub-factors. Based on these findings, the implication of future research is discussed.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.10
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• pp.231-238
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• 2019

Analyzing next-generation genome sequencing data in a conventional way using single server may take several tens of hours depending on the data size. However, in order to cope with emergency situations where the results need to be known within a few hours, it is required to improve the performance of a single genome analysis. In this paper, we propose a parallelized method for pre-processing genome sequence data which can reduce the analysis time by utilizing the big data technology and the highperformance computing cluster which is connected to the high-speed network and shares the parallel file system. For the reliability of analytical data, we have chosen a strategy to parallelize the existing analytical tools and algorithms to the new environment. Parallelized processing, data distribution, and parallel merging techniques have been developed and performance improvements have been confirmed through experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.244-251
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• 2020

This paper presents a design of the Meta-Class Repository (MCR) which maintain syntactically analyzed and structured meta-class information from UML diagrams, and then proposes 'meta-class,' also known as super-class, to construct structured information analyzed syntactically. The MCR is a collection of these meta-classes which contains the information extracted from diagrams. This paper also presents a design of the Code Generation Engine (CGE) which roles generating codes corresponding classes from UML diagrams based on the MCR maintaining a collection of meta-classes which is syntactically-analyzed and constructed in previous process. The logics of CGE are designed to generate codes collaborated with MCR and CGE with integration. The logics of CGE mechanism is presented with the form of finite state machine to present the algorithms of code generation formally and have the advantages of simplicity and easiness in development.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.91-98
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• 2021

In most hacking attacks, hackers tend to access target systems in a variety of circumvent connection methods to hide their original IP. Therefore, finding the attacker's IP(Internet Protocol) from the defender's point of view is one of important issue to recognize hackers. If an attacker uses a proxy, original IP can be obtained through a program other than web browser in attacker's computer. Unfortunately, this method has no effect on the connection through VPN(Virtual Private Network), because VPN affects all applications. In an academic domain, various IP traceback methods using network equipments such as routers have been studied, but it is very difficult to be realized due to various problems including standardization and privacy. To overcome this limitation, this paper proposes a practical way to use client's network configuration temporarily until it can detect original IP. The proposed method does not only restrict usage of network, but also does not violate any privacy. We implemented and verified the proposed method in real internet with various VPN tools.