• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.69-71
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• 2020

Principal Component Analysis (PCA) is an effective data analysis technique which is commonly used for fault detection on collected data of Wireless Sensor Networks (WSN), However, applying PCA on the whole data make the detection performance low. In this paper, we propose Joint PCA and Adaptive Threshold for Fault Detection (JPATAD). Experimental results on a real dataset show a remarkably higher performance of JPATAD comparing to conventional PCA model in detection of noise which is a popular fault in collected data of sensors.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.721-722
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• 2023

본 연구에서는 공업계 고등학교 재학생 중 자율주행로봇 대회에 출전하려는 학생들을 대상으로 삼았다. 자율주행로봇 대회를 준비할 때는 프로그래밍, 로봇제작 등을 연습한다. 학생들은 대회를 준비하면서 성과에 대한 부담을 많이 가지고 있지만, 대회를 준비하는 과정에서 본인의 의도대로 결과물이 나타나지 않았을 때, 학습된 무기력에 빠질 수 있다. 이에 본 연구에서는 자율주행로봇 대회의 출전을 준비하면서 발생할 수 있는 학습된 무기력을 극복하기 위하여 회복탄력성을 증진할 수 있는 방안을 제시하였다.

• Journal of the Korea Society of Computer and Information
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• v.19 no.4
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• pp.17-24
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• 2014

Detecting data races is important for debugging shared-memory programs with nested parallelism, because races result in unintended non-deterministic executions of the program. It is especially important to detect the first occurred data races for effective debugging, because the removal of such races may make other affected races disappear or appear. Previous dynamic detection tools for first race detecting can not guarantee that detected races are unaffected races. Also, the tools does not consider the nesting levels or need support of other techniques. This paper suggests a post-mortem tool which collects candidate accesses during program execution and then detects the first races to occur on the program after execution. This technique is efficient, because it guarantees that first races reported by analyzing a nesting level are the races that occur first at the level, and does not require more analyses to the higher nesting levels than the current level.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.207-215
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• 2011

Due to the increasing availability and popularity of digital television (DTV), the numbers of TV channels and programs that can be selected by consumers are also increasing rapidly. Therefore, searching for interesting channels and program via remote controls or channel guide maps can be frustrating and slow. In this paper, in order to better satisfy consumers, we propose a dynamic channel surfing scheme that reduces the channel seek distance in DTV. The proposed scheme dynamically rearranges the channel sequences according to the channel currently being watched to reduce the channel seek distance. The results of a simulation experiment demonstrate that the proposed dynamic channel surfing scheme reduces the channel seek distance for DTV channel navigation when up-down channel selection interfaces are used.

• Journal of the Korea Society of Computer and Information
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• v.18 no.11
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• pp.241-254
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• 2013

The purpose of this study is to analyse the effects of social network service on the collaborative learning. Four groups were categorized depending on the use of different types of the social network services - Kakao Talk, Facebook, both Kakao Talk and Facebook, and unused group. A preliminary test revealed that there was no difference in mobile efficacy, career decision making self-efficacy, course interest among the four groups. In the post test, the groups that used either Kakao Talk group or the group that used both Kakao Talk and Facebook retained significantly higher average score in team collaboration scale than Facebook group and unused group. The analysis of the messages in Facebook exhibited that the group used both Kakao Talk and Facebook generated larger number of messages, read, replies, clicks of "good" than the groups used only Facebook. These results strongly support the statistical significance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.7
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• pp.801-806
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• 2019

Recently, each university has been lecturing a lot on the liberal arts subject by emphasizing software education. However, students are often motivated by the difficulty of learning programming, the inability to recognize why they should learn programming, or even the fact that they do not try. The reason for the resilience is to guide programming learning to have the power to recover from the point of abandonment to proceed with the learning again. In this study, recovery elasticity pre-post-examination was conducted on the parts that learned scratches and those that learned Python. Studies have shown that while Scratch appears to be trying to accept and work harder, Python has been relatively more difficult than Scratch. It is expected that this study will help identify the factors that can sustain programming learning.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.135-144
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• 2020

In graph theory, the least-cost path is discovered by searching the shortest path between a start node and destination node. The least cost is calculated as a one-dimensional value that represents the difference in distance or price between two nodes, and the nodes and edges that comprise the lowest sum of costs between the linked nodes is the shortest path. However, it is difficult to determine the shortest path if each node has multiple attributes because the number of cost types that can appear is equal to the number of attributes. In this paper, a shortest path search scheme is proposed that considers multiple attributes using the Euclidean distance to satisfy various user requirements. In simulation, we discovered that the shortest path calculated using one-dimensional values differs from that calculated using the Euclidean distance for two-dimensional attributes. The user's preferences are reflected in multi attributes and it was different from one-dimensional attribute. Consequently, user requirements could be satisfied simultaneously by considering multiple attributes.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.211-222
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• 2022

The purpose of this study is to indicate the direction of the future university classes in the post-COVID era, comparing and analyzing lecture evaluation of pre and post COVID-19. To this end, 4 yeard data were used from 2018 to 2019 for pre COVID-19 and form 2020 to 2021 data for post COVID-19. The results were as follows. In the case of liberal arts, "assignments" was the word with the highest frequency and degree centrality(DC) regardless of pre and post-COVID-19 In the major, "understanding" appeared as the most important word. The result of the ego network analysis indicated that "video lecture" and "non-face-to-face classes" were difficult and "interaction" between the professor and the students was important. As a results, it is important to reduce the weight of assignments and increase interaction with students in liberal arts classes. In the case of majors, it is necessary to operate face-to-face classes rather than non-face-to-face classes, and to organize the contents of videos without difficulty.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.698-705
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• 2014

We propose a new development for calculating a computer-generated hologram (CGH) through the use of multiple general-purpose graphics processing units (GPGPUs). For optimization of the implementation, CGH parallelization, object point tiling, memory selection for object point, hologram tiling, CGMA (compute to global memory access) ratio by block size, and memory mapping were considered. The proposed CGH was equipped with a digital holographic video system consisting of a camera system for capturing images (object points) and CPU/GPGPU software (S/W) for various image processing activities. The proposed system can generate about 37 full HD holograms per second using about 6K object points.

• Proceedings of The KACE
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• 2018.08a
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• pp.15-18
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• 2018

4차 산업혁명 시대는 더 이상 먼 미래가 아닌 현실로 다가왔다. 주요 선진국 뿐 아니라 세계 각국에서 미래 인재 양성을 위해 다양한 연구와 노력을 기울이고 있다. 이에 따른 소프트웨어 교육에 대한 요구를 수용하기 위해 교육과정의 변화 및 교과 편성을 활발하게 진행 중에 있고, 우리나라 역시 올해부터 '정보'교과를 중학교에서 34시간 이상 필수로 이수하도록 하였다. 본 논문에서는 국가 수준의 커리큘럼이 없이 사교육 중심으로 이루어지고 있는 유아대상 소프트웨어 교육의 내용체계를 제안하였다. 유아 대상 소프트웨어 교육은 누리과정에 자연스럽게 녹아들어 아이들이 행동 발달에 맞는 커리큘럼으로 개발되어 쉽고 재미있게 놀이와 체험을 통해 교육을 받을 수 있도록 지속적인 연구가 필요하다.