• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.378-384
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• 2023

In this study, we aim to derive the descriptor vector conditions that can simultaneously achieve the efficiency and accuracy of artificial Neural Network Potentials (NNP). The material system selected is silicon, a highly applicable material in various industries. Atomic structure-dependent energy data for training artificial neural networks were generated through density functional theory calculations. Behler-Parrinello type atomic-centered symmetric functions were employed as descriptors, and various length vector NNPs were generated. These NNPs were applied to reproduce the structure and mechanical properties of silicon materials in molecular dynamics simulations. In our findings, the minimum vector length for achieving both learning and computational efficiency while maintaining property reproducibility is approximately 50. It was also observed that, for the same conditions, incorporating more angle-dependent symmetric functions into the descriptor vector, could enhance the accuracy of NNP. Our results can provide guidelines for optimizing the conditions of descriptor vectors to achieve both efficiency and accuracy of NNP, simultaneously.

• Journal of the Korean earth science society
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• v.32 no.2
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• pp.200-211
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• 2011

The purpose of this study is to investigate the effects of astronomical animation module on students' conceptual change regarding the concepts of diurnal motion of stars. Four students participated in this study, who never learned about the diurnal motion of stars. An animation module was developed by using Flash MX to readily understand the concept of space. In addition, we inserted a teacher's voice with supplementary materials into the animation module to help students learn individually. The animation module was comprised of the movement of the Earth, the Moon and the planet. The earth science gifted students' preconception on diurnal motion of stars was analyzed with pre-test using questionnaires and interviews. After the instruction with animation module, the effect of conceptual change was examined by comparing pre and post-test. The results indicated that three students correctly presented about the motion of the star by all directions in middle latitude. Four students showed their understanding that stars travelled straight in all directions. Finally, all of four students whose preconceptions were that the star rotated perpendicularly showed the conceptual change of diurnal motion that the star traveled diagonally.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.926-932
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• 2009

Recently many research reports on effective use of mobile devices for museums to provide information on displayed artifacts providing individualized learning space, collaborative learning, and discovery learning, Such devices have many possibilities to support learning as a participatory media and social network. Mobile devices are used, however, limited for its usability and lack in providing expected learning experiences. It offers one-way interaction and they are often limited in providing customized services for different patrons to experience learning and entertainment. In this research, we have adopted user centered design approach to identify the needs and possible usage of PDA system in the museum. Research methods include contextual observation and inquiry with symbolic interactionism for qualitative research and its epistemology. We have developed conceptual model with scenario and storyboard method, and developed vertical prototype with Flash.

• Communications of Mathematical Education
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• v.33 no.3
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• pp.295-317
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• 2019

Angle concept is widely used in all mathematics curriculums and is a basic concept in geometric domain. Since angle have a multifaceted and affect subsequent learning, it is necessary for students to understand various angle concepts. In this study, Singapore, U.K., Australia, and U.S. are selected as comparable countries to examine the angle-related contents and learning process that appear in the curriculum as a whole, and then look at the perspectives and the size aspects of angle in detail and give implications to the Korean curriculum based on them. According to the analysis, the four countries except Korea, supplement angle, complement angle, angles on a straight line, angles at a point, and finding angle were explicitly covered in the curriculum. And most countries gradually covered angle-related contents over several years, compared to Korea which intensively studied in a particular school year. In common, definition of angle was described as static, measurement of angle was described as dynamic. But in Korean curriculum, dynamic views on angles are described later and less compared to other countries, and range of angle size was narrower than in other countries'. From this comparison, this study suggest to discuss how to place and develop various contents of characteristics of angle in curriculum, address the angle using both static and dynamic perspectives, and introduce the angle size as the amount of rotation to learn the reflex angle, $180^{\circ}$, $360^{\circ}$ angle.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.41-51
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• 2023

In this paper, we propose a technique of multi-time window feature extraction for anger detection in gait data. In the previous gait-based emotion recognition methods, the pedestrian's stride, time taken for one stride, walking speed, and forward tilt angles of the neck and thorax are calculated. Then, minimum, mean, and maximum values are calculated for the entire interval to use them as features. However, each feature does not always change uniformly over the entire interval but sometimes changes locally. Therefore, we propose a multi-time window feature extraction technique that can extract both global and local features, from long-term to short-term. In addition, we also propose an ensemble model that consists of multiple classifiers. Each classifier is trained with features extracted from different multi-time windows. To verify the effectiveness of the proposed feature extraction technique and ensemble model, a public three-dimensional gait dataset was used. The simulation results demonstrate that the proposed ensemble model achieves the best performance compared to machine learning models trained with existing feature extraction techniques for four performance evaluation metrics.

• Journal of the Korean Data and Information Science Society
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• v.21 no.1
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• pp.147-153
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• 2010

It is generally believed that teaching probability with the help of coin tossing has a long history. In textbooks about elementary probability or statistics, problems on unfair coins as well as fair ones are frequently given. However it is known that nobody has met an unfair coin with a fixed head probability which is different from 0.5 in flesh and blood. In this study a coin bent along with the middle line of the coin is suggested as an unfair one. By flipping bent coins with various angle, the ratios of head of the coins are obtained. The bent coins might be used as experimental tools for teaching of probability concept.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2705-2711
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• 2011

The recent development in multimedia technology such as audio technology needs high quality audio system. Especially, Real Audio Technology is to be developed to play realistic sound. To meet this demands, researches on 3-Dimensional Audio which provides realistic audio effect in virtual reality and augmented reality are conducted. In this paper, how to provide realistic audio effect by using better audio technologies in augmented reality was investigated. In the study, the movements of the 3-Dimensional model on the markers were used to provide the sense of reality in virtual and real world. Namely, the sound was modified according to the movement of the model. The change in distance and angle of the model affected the sound volume and the pitch.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.466-470
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• 2007

보안첨단화의 필요성 증대로 인하여 복합적이고 고기능의 보안 감시 시스템의 수요가 급속도로 확대되면서 보안은 안전하고 행복한 생활을 만드는데 없어서는 안될 중요한 역할을 하게 되었다. 최근, 디지털 영상기술의 급속한 발달과 보급은 이러한 보안 감시 시스템을 가능하도록 하였다. 본 논문은 다수의 카메라로부터 사람들의 움직임을 연속적으로 식별하고 추적할 수 있는 향상된 지능화 방법을 제안한다. 이 방법을 통해 카메라들 간의 위상이 자동으로 구성되고 객체의 움직임을 기반으로 학습하여 카메라들간의 거리, 객체와 카메라와의 거리, 카메라의 각도를 자동적으로 연산할 수 있도록 하였다. 이러한 자가 구성 단계 이후에 사람의 움직임을 추적하게 된다. 추적에서 사람들을 식별하는 단계가 선행되어야 하며, 이를 위해 머리, 몸, 손, 다리로 분리하여 각각의 정보들을 식별자로 사용하였다. 이러한 외형 식별자와 객체의 출몰간의 시간차를 이용해 다수의 카메라들로부터 객체를 연속적으로 추적하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.349-356
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• 2006

A cartpole system is controlled by a control system consisting of two fuzzy controllers cooperating by a CMAC. Each controller uses 2 different input variables and yields the control force provided to the CMAC. The cooperation is due to training of the CMAC supervised by a judge which selects training information for the CMAC between two fuzzy controllers. The control scheme could be appreciated in terms of the tight structure of the controller, simple cooperating scheme due to the CMAC training, and accomplishing control goal that could not be attained by individual controllers.

• Journal of Korea Game Society
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• v.14 no.5
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• pp.183-192
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• 2014

In recent times, a trend has emerged which rejects negative elements such as violence and gambling associated with games, and emphasizes positive functions such as academic study, which is a desirable phenomenon. Serious games have great potential and unlimited boundaries in their scope, and need much study and research from various perspectives. Especially today, in enhancing the national image of Korea with "Korean games" for the next generation, creative storytelling is urgently required. In this study, I aim to investigate the functions and roles of serious games and to foresee their future direction of development. I also examine the essential elements of storytelling in games suitable for the next generation.