• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.48.2-48.2
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• 2016

The wide-field and the round-the clock operation capabilities of the KMTNet enables the discovery, astrometry and follow-up physical characterization of asteroids and comets in a most efficient way. We collectively refer to the team members, partner organizations, the dedicated software subsystem, the computing facility and research activities as Deep Ecliptic Patrol of the Southern Sky (DEEP-South). Most of the telescope time for DEEP-South is devoted to targeted photometry of Near Earth Asteroids (NEAs) to push up the number of the population with known physical properties from several percent to several dozens of percent, in the long run. We primarily adopt Johnson R-band for lightcurve study, while we employ BVI filters for taxonomic classification and detection of any possible color variations of an object at the same time. In this presentation, the progress and new findings since the last KAS meeting will be outlined. We report DEEP-South preliminary lightcurves of several dozens of NEAs obtained at three KMTNet stations during the first year runs. We also present a physical model of asteroid (5247) Krylov, the very first Non principal Axis (NPA) rotator that has been confirmed in the main belt (MB). A new asteroid taxonomic classification scheme will be introduced with an emphasis on its utility in the LSST era. The progress on the current version of automated mover detection software will also be summarized.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.197-207
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• 1996

Maturity is expressed as the integral of time and temperature of concrete above a datum temperature. The maturity concept proposes that concrete of the same mix at the same maturity has the same strength, whatever combination of temperature and time makes up that maturity. In this study, the Nurse-Saul function which was proposed to account for the effects of temperature and time on strength developrnent is used in computing maturity. After existing various functions are considered to relate concrete strength to the maturity value, new strength-maturity function is proposed. Tests ;ire conducted in order to determine d datum temperature and compare prechction value with measured concrete strength. The constants in proposed prediction equation are determined from test results, and the equation is adopted to predict the strength of slab. The slab was cast in the laboratory from the same batch of mold, and cores are cut from slab in order to estimate the actual strength. These values are used to compare with predicted value. The present study allows more realistic determination of early-age strength of concrete and can be efficiently used to control the quality in actual construction.

• Journal of The Korean Association of Information Education
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• v.22 no.2
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• pp.285-295
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• 2018

The purpose of this study is to develop a software education program using micro:bit based on the ADDIE development model and to analyze the effects of the development of creativity of elementary school students. The education program was developed based on the results of the pre-demand analysis conducted on 40 elementary school teachers in Jeju. In order to verify the effectiveness of the developed education program, 42 students who participated in the education donation program conducted by ${\bigcirc}{\bigcirc}$ University were enrolled in 24 hours for 7 days for 6 days. The results of the analysis show that the software education program developed in this study has positive effects on the creativity factors by improving the programming ability of elementary school students.

• Journal of The Korean Association of Information Education
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• v.14 no.4
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• pp.527-536
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• 2010

Ubiquitous computing and mobile technologies provide much scope for designing innovative learning experiences that can take place in a variety of indoor and outdoor settings, such as botanical gardens, parks, museums and classrooms. In this paper, we present our own innovative work for bridging indoor and outdoor field-trip learning activities with the support of RFID with reader device on ubiquitous environments. The function of our system is based on strategically located RFID tags placed on objects around settings which are identified using the mobile device installed to an RFID reader. The mobile device reads the RFID tag and sends the learner's request to the field-trip learning system. And learners can be learning activities according to theirs learning levels. We also focus on the use of intelligent agents to customize learning contents for individual learners. The result of our experiment indicates that learner enjoyed learning where mobile devices are used in the system, supporting the learning activities in the context of which they are taking place.

• Journal of The Korean Association of Information Education
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• v.17 no.3
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• pp.233-242
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• 2013

"Problem-solving methods and procedures" sections in the 2009 revised informatics curriculum emphasized active use of algorithmic thinking to solve problems. And it is proposed to solve the various problems of real life using programming language for the implementation of the algorithm. Recently, various Educational Programming Language has been developed for elementary programming activity and many researches showed that students' cognitive burden was reduced in learning programming language with Educational Programming Languages. However implementation of the algorithm is difficult for novice programmer. For the reason, effective way is required for elementary students to connect design of the algorithm and implementation of the algorithm. Therefore, in this study propose the algorithm design worksheets that it is possible to create an algorithm to describe the content needed to implementation in programming education. And this study proved the effect of the algorithm design learning tools through experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.237-245
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• 2012

This paper describes an acoustic echo canceller with double-talk by the blind signal separation. The acoustic echo canceller is deteriorated or diverged in the double-talk period. So we use the blind signal separation to estimate the near-end speech signal and to eliminate the estimated signal from the residual signal. The blind signal separation extracts the near-end signal with dual microphones by the iterative computations using the 2nd order statistical character. Because the mixture model of blind signal separation is multi-channel in the closed reverberation environment, we used the copied coefficients of echo canceller without computing the separation coefficients. By this method, the acoustic echo canceller operates irrespective of double-talking. We verified performances of the proposed acoustic echo canceller by simulations. The results show that the acoustic echo canceller with this algorithm detects the double-talk periods thoroughly, and then operates stably in the normal state without the divergence of coefficients after ending the double-talking. And it shows the ERLE of averagely 20dB higher than the normal LMS algorithm.

• The Journal of Korean Association of Computer Education
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• v.23 no.2
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• pp.41-51
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• 2020

The goal of this study is to test the hypothesis that the practicality of EXCEL VBA will be beneficial for SW education for SW non-majors. To this end, we planned the education for non-majors using the EXCEL VBA and conducted 15 weeks of education. According to a follow-up survey conducted after the 15-week education period, 72.21% of the survey respondents said EXCEL was practical. Also, learners who were aware of the necessity of SW education and the importance of SW competence recognized that the computational thinking education using EXCEL VBA had a positive effect on the improvement of computer-related knowledge and experience. Also, learners recognized that learning with EXCEL was easy, while learning with VBA was difficult. The learning process using VBA needs to be composed of project-oriented educational contents that can give a sense of achievement to learners rather than programming-oriented education. And continuous research on project-based learning is needed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.698-707
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• 2017

This paper deals with predictive control methods of mobile robots for reference trajectory tracking control. Predictive control methods using predictive model are known as effective schemes that minimize the future errors between the reference trajectories and system states; however, the amount of real-time computation for the predictive control are huge so that their applications were limited to slow dynamic systems such as chemical processing plants. Lately with high computing power due to advanced computer technologies, the predictive control methods have been applied to fast systems such as mobile robots. These predictive controllers have some control parameters related to control performance. But these parameters have not been optimized. In this paper we employed the genetic algorithm to optimize the control parameters of the predictive controller for mobile robots. The improved performances of the proposed control method are demonstrated by the computer simulation studies.

• The KIPS Transactions:PartA
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• v.9A no.3
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• pp.371-378
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• 2002

The EMFG (Extended Mark Flow Graph) is known as a graph model for representing the discrete event systems. In this paper, we introduce input/output matrixes representing the marking variance of input/output boxes when each transition fires in an EMFG, and compute an incidence matrix. We represent firing conditions of transitions to a firing condition matrix for computing a firable vector, and introduce the firing completion vector to decide completion of each transition’s firing. By using them, we improve an analysis algorithm of the EMFG’s operation to be represented all the process of EMFG’s operation mathematically. We apply the proposed algorithm to the system repeating the forward and reverse revolution, and then confirm that it is valid. The proposed algorithm is useful to analysis the variant discrete event systems.

• Convergence Security Journal
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• v.19 no.5
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• pp.47-53
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• 2019

Network-based sharing of information has evolved into a cloud service environment today, increasing its number of users rapidly, but has become a major target for network-based illegal attackers.. In addition, IP spoofing among attackers' various attack techniques generally involves resource exhaustion attacks. Therefore, fast detection and response techniques are required. The existing detection method for IP spoofing attack performs the final authentication process according to the analysis and matching of traceback information of the client who attempted the connection request. However, the simple comparison method of traceback information may require excessive OTP due to frequent false positives in an environment requiring service transparency. In this paper, symmetric key cryptography based on traceback information is used as mutual authentication information to improve this problem. That is, after generating a traceback-based encryption key, mutual authentication is possible by performing a normal decryption process. In addition, this process could improve the overhead caused by false positives.