• Journal of The Korean Association For Science Education
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• v.25 no.4
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• pp.472-479
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• 2005

The purpose of this study was to develop an inquiry-based professional development program for in-service secondary science teachers and to investigate it's application. The inquiry-based professional development program was reconstructed based on SSCS problem-solving model, which is composed of 4 stages of search, solve, create, and share. The 28 science teachers' understanding of the SSCS program were investigated as implementing the program. As a result of this study, 8 SSCS modules have developed as the science teachers have searched, solved, created, and shared various situated problems. The science teachers found themselves to have positive perception of SSCS program. The SSCS program was effective in changing the learners' teaching/learning attitude and to develop individual scientific thinking. To make the SSCS problem solving successful and more effective, both science teachers' professionalism and pedagogical knowledge for selecting topic as the levels of learner should be considered.

• Journal of Gifted/Talented Education
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• v.18 no.3
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• pp.497-518
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• 2008

This study aims to examine how Science Gifted Education Center(SGEC) affect the decision of graduates of gifted education institute in applying for science-related Special high school. To this end, the study investigated factors that affected their decision on applying for higher SGEC, such as career goal prior to their admission to a SGEC, motivation for the admission, and curricular activities at SGEC. A questionnaire survey was administered on 30 students, and resulting data were used as basic information to construct interview questions. Selected 22 students among them were interviewed separately, with transcripts of the recorded interviews being analyzed. The results of the study indicate that among many factors of SGEC for the gifted which affected student's choice of special-purpose high school of science, activities of the center putting an emphasis on open research activities and social interaction had a positive effect on the students' choice of special high school.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.370-378
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• 2007

In wireless sensor networks (WSNs), thousands of sensors are often deployed in a hostile environment. In such an environment, WSNs can be applied to various applications by using the absolute or relative location information of the sensors. Until now, the time-of-arrival (TOA) based localization method has been considered most accurate. In the TOA method, however, inaccuracy in distance estimation is caused by clock drift and clock skew between sensor nodes. To solve this problem, several numbers of periodic time synchronization methods were suggested while these methods introduced overheads to the packet traffic. In this paper, we propose a new localization method based on multiple round-trip times (RTOA) of a signal which gives more accurate distance and location estimation even in the presence of clock skew between sensor nodes. Our experimental results show that the Proposed RTOA method gives up to 93% more accurate location estimation.

• Journal of KIISE:Software and Applications
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• v.27 no.5
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• pp.575-582
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• 2000

Because FIFO thread scheduling used in the existing multithreaded models does not consider locality in programs, it may result in the decrease of the performance of execution, caused by the frequent context switching overhead and delay of execution of relatively short frames. Quantum unit scheduling enhances the performance a little, but it still has the problems such as the decrease in the processor utilization and the longer delay due to its heavy dependency on the priority of the quantum units. In this paper, we propose shortest-frame-first(SFF) thread scheduling algorithm. Our algorithm selects and schedules the frame that is expected to take the shortest execution time using thread size and synchronization information analyzed at compile-time. We can estimate the relative execution time of each frame at compile-time. Using SFF thread scheduling algorithm on the multithreaded models, we can expect the faster execution, better utilization of the processor, increased throughput and short waiting time compared to FIFO scheduling.

• Journal of KIISE:Software and Applications
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• v.31 no.6
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• pp.773-783
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• 2004

This paper presents a method for real-time verification of Statecharts. Statecharts has been widely used for real-time reactive systems, and supports two time models: synchronous and asynchronous. However, existing real-time verification methods for them are incompatible with the asynchronous time model or increase state space by introducing new variables to the target models. We solved these problems by extending existing model checking algorithms. The extended algorithms can be used with both time models of Statecharts because they consider time increasing transitions only. In addition, they do not increase target state space since they count those transitions internally without additional variables. We extended an existing model checker, NuSMV, based on the proposed algorithms and conducted some experiments to show their advantage.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.4
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• pp.150-157
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• 2008

This paper presents a design and implementation of realtime video player that operates on a tiled-display system consisting of multiple PCs to provide a very large and high resolution display. In the proposed system, the master process transmits a compressed video stream to multiple PCs using UDP multicast. All slaves(PC) receive the same video stream, decompress, clip their designated areas from the decompressed video frame, and display it to their displays while being synchronized with each other. A simple synchronization mechanism based on the H/W clock of each slave is proposed to avoid the skew between the tiles of the display, and a flow-control mechanism based on the bit-rate of the video stream and a pre-buffering scheme are proposed to prevent the jitter The proposed system is implemented with Microsoft DirectX filter technology in order to decouple the video/audio codec from the player.

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.177-182
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• 2001

An instructional model using multiple analogies according to component process (MACP) was designed on the vasis of schema theory and comornent process theory in analogical reasoning. This model has ？ phases: introducting multiple analsgs, extracting multiple analogs, extracting common attributes of analogs, introducing target conanother context. Te instructional effects of this model upon students' conceptual understanding and learning motivation were compared with those of the Teaching-With-Analogy (TWA) and non-analogy instructions. Three classes of 8th grade were randomly assigned to MACP, TWA, and control group, respectively, Subjects were taught about chemical changes and reactions for 10 class hours. The ANCOVA results indicated that the scores of the conceptions test for the MACP group were significantly higher than for the control graup. However, no significant differences were found among the three groups in the test scores of learning motivation.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.6
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• pp.273-283
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• 2008

Many embedded real-time systems have adopted processors supported with dynamic voltage scaling(DVS) recently. Power is one of the important metrics for optimization in the design and operation of embedded real-time systems. We can save considerable energy by using slowdown of processor supported with DVS. In this paper, we propose heuristic algorithms to calculate task slowdown factors for an efficient energy consumption in embedded real-time systems with task synchronization. The previous algorithm has a following constraint : given the tasks are ordered in a nondecreasing order of their relative deadline, the task slowdown factors computed are in a nonincreasing order. In this paper, we relax the constraint and propose heuristic algorithms which have the same time complexity that previous algorithm has and can save more energy. Experimental results show that the proposed algorithms are energy efficient.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.661-673
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• 2021

This study is a descriptive study to understand the effect on the health behavior compliance of men who got coronary intervention, focusing on the elapsed period. The subjects of this study were 249 men who underwent coronary intervention at a university hospital, and the collected data were analyzed using Stepwise multiple regression. As a result of the study, the influencing factors the implementation of healthy behaviors were self-regulation(β=0.35, p<.001), risk factors among educational request(β=-0.26, p<.001), and the elapsed period(β=0.19, p<.001), marital status(β=0.15, p=.001), educational level(β=-0.12, p=.035), and the total explanatory power was 29.1%. IIn order to increase the health behavior performance of male patients who underwent coronary intervention, it is necessary to develop a program that can strengthen the autonomous motivation of subjects with high severity and elapsed time of less than 1 year and more than 1 year.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.103-112
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• 2021

The purpose of this study was to identify motivation factors of marathon crew members using Q methodology. Four distinct factors were emerged throughout the analysis: the first factor is 'the major event participation preference' who is seeking mega or big marathon events to enjoy festival atmosphere. The second factor is 'special meaningful event participation preference' who prefers to participate marathon events to help disabled people or childeren. The third factor is 'the tourism type marathon event participation preference' who is seeking to participate marathon event with tourism. The last factor is 'the preference type for record breaking ' who is seeing the place is accessability, a good season and running course to break personal record.