• Korean Journal of Optics and Photonics
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• v.31 no.1
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• pp.37-44
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• 2020

In this study, we propose a design method to optimize the electro-optical efficiency of a planar solar cell structure by adjusting one-dimensionally periodic emitter electrodes. Since the aperture ratio of the active layer decreases as the period of the emitter electrode decreases, the amount of light absorption diminishes, affecting the performance of the device. Here we design the optimal structure of the periodic emitter electrode in a simple planar solar cell, by simulation. In terms of optics, we find the condition that shows optical performance similar to that of a reference without the emitter electrode. In addition, the optimized electrode structure is extracted considering both the optical and electrical efficiency. This work will help to increase the utilization of solar cells by suggesting a structure that can most efficiently transfer charge generated by photoelectric conversion to the electrodes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.987-999
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• 2021

Recently, Federated learning has become an issue due to privacy invasion caused by data. Federated learning is safe from privacy violations because it does not need to be collected into a server and does not require learning data. As a result, studies on application methods for utilizing distributed devices and data are underway. However, Federated learning is no longer safe as research on the reconstruction attack to restore learning data from gradients transmitted in the Federated learning process progresses. This paper is to verify numerically and visually how well data reconstruction attacks work in various data situations. Considering that the attacker does not know how the data is constructed, divide the data with the class from when only one data exists to when multiple data are distributed within the class, and use MNIST data as an evaluation index that is MSE, LOSS, PSNR, and SSIM. The fact is that the more classes and data, the higher MSE, LOSS, and PSNR and SSIM are, the lower the reconstruction performance, but sufficient privacy invasion is possible with several reconstructed images.

• Journal of the Korea Computer Graphics Society
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• v.25 no.3
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• pp.31-41
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• 2019

A fog screen consists of tiny water drops and the viewers see the image transmitted through the fog screen. In contrast to ordinary screens, the viewers can see the actors passing through the image on the fog screen on stage. In this paper, we describe methods to build a top-down fog screen where fog particles generated in top space fall by gravity forming a flat vertical screen. We use a fog generation technique in which fog particles come out of the water surface when ultrasound vibrators immersed in water tank vibrate. We describe how fog particles form a flat screen while coming out of the fog passage tunnel, by generating guiding winds beside the fog screen. This technique utilizes the principle that fog particles are generated on the surface of a water tank by an ultrasonic vibrator placed in a water tank. The technique of forming a guiding wind on both sides of the passage exit where the fog comes out and the design and manufacturing method of the fog screen generating device are described so that the generated fog group can maintain one plane.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.180-207
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• 2010

Technological innovations in the 21th Century greatly change the society. The radical advance in computer science brought changes and increased efficiency into society in general. The field of archaeology is also highly influenced and attempts to improve previous manually conducted field survey and research have been actively made. In order to supplement incomplete data set from archaeological excavation, the ways to use computer have been highly explored. GIS is one of them. However, use of GIS has been limited to document locations and to produce distribution map of features using digital map. There are no proper guides to employ GIS for academic research, so that it is hard for beginners to learn how to make use of GIS. In this paper, functions of GIS are introduced even for beginners, including definition of GIS and its archaeological use. It is also explained how to get DEM from digital map to do spatial pattern analysis. Various GIS special pattern analyses using DEM and 3D simulation are presented, as well.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.211-216
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• 2021

Multiple UAV System has been used for various purposes such as reconnaissance, networking and aerial photography. In such systems, it is essential to form and maintain the formation of multiple UAVs. This paper proposes the algorithm that produces an autonomous distributed control for each vehicle for a flexible formation. This command is a repulsive force in the form of the second-order system by the nearest UAV or mission area. The algorithm uses the relative position/speed through sensing and communication for calculating the command without external intervention. The command allows each UAV to follow the reference distance and fill the mission area as densely as possible without overlapping. We determine the reference distance via optimization technique solving the packing problem. The mission area comprises the desired formation outline and can be set flexibly depending on the mission. Numerical simulation is carried out to verify the performance of the proposed algorithm under a complex and flexible environment. The formation is formed in 26.94 seconds and has a packing density of 71.91%.

• Journal of Music and Human Behavior
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• v.17 no.2
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• pp.83-100
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• 2020

The purpose of this study was to develop and validate the music program based on social-emotional learning (SEL) to facilitate social inclusion between children with and without disabilities studying together in inclusive classes. For program development, the literature on social inclusion programs and SEL programs were analyzed. Program components were extracted from the literature review and based on the review activities were also selected. The participants were fifth- and sixth-grade elementary school students, including children with intellectual disabilities, and the program was implemented over 12 sessions during the students' creative experiential activity class. The validity of the program was evaluated by teachers and the specified program contents were modified and finalized reflecting the professionals' recommendations. This study supports that SEL-based music program can be effectively applied to inclusive education. The developed music program is also expected to improve the social and emotional capacity of children in inclusive classrooms and to increase the social inclusion between children with and without disabilities.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.15-23
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• 2022

The operation method of offline venues such as local festivals usually has problems such as the absence of real-time events and booth information, wasting time in the process of purchasing and receiving goods, and stagnating the movement of guests. This study increases the convenience of guests and managers by integrating all contents in the venue in the form of booth, thereby increasing the uniformity of event information and the efficiency of booth operation. In addition, a system was designed to minimize movement problems and improve performance by detecting the movement of guests within the venue and increasing the efficiency of arranging booths based on location data. It has been developed as a low-cost system that measures wireless packets with portable wireless LAN APs and control units. This has advantages in the operation of the venue, which consists of the installation and dismantling of variable booths in a short period of time. It is expected that the integrated operation of the venue will be utilized by linking the movement data of guests to activate visits and increase sales through data-based promotions.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.293-294
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• 2023

2023년 8월 3일 다중이용시설과 운송시설이 맞닿아 있는 서현역 부근의 다중이 밀집한 장소에서 차량돌진 및 흉기난동의 묻지마 범죄가 발생하였다. 차량을 인도로 몰아 보행자를 들이받은 뒤 백화점 내부로 들어가 흉기를 휘둘러 차량돌진으로 5명, 흉기난동으로 9명의 피해자가 발생하였다(리차드김, 2023). 서현역의 묻지마 범죄 이후, '살인예고 지도' 서비스의 등장하면서 많은 이용객이 상시 붐비는 번화가 및 백화점 등의 다중이용시설을 이용하는 시민들의 불안감이 전국적으로 크게 확산하고 있다(김잔디 & 최윤선, 2023). 급격히 늘어나는 국민의 불안감으로 정부에서는 '묻지마 범죄'를 '이상동기범죄'로 명명하고 근절을 위해, 사실상 테러와 비슷한 수준의 강력한 대책을 추진하고 있다(강은민, 2023). 이상동기범죄에 따른 강력한 대책으로 국무조정실(대테러센터), 경찰청 등 관계부처의 다중이용시설 대한 안전대책들이 강구되어지고 실정에서 「경비업법」에 따라 시설의 위험발생을 방지하는 업무를 담당하고 있는 민간 경비원에게 이용객의 안전을 보호하고 피해를 최소화하기 위한 일선 역할이 중요해졌다. 하지만, 이상동기범죄에 대한 일선의 초동대응이 인력과 장비, 정당방위에 대한 법제도의 뒷받침 미흡 등으로 인해 민간 경비원의 실질적인 대응이 어려운 실정이다. 많은 사람의 왕래가 있는 다중이용시설에서의 민간 경비원 최소 경력배치 기준, 현행범 제압을 위한 무기사용 기준, 이용객 보호를 위한 경비원 위력 사용 기준 등의 제도적으로 마련되어 있지 않아 민간 경비원이 범죄로부터 시설 이용객을 보호하는 것은 쉽지 않은 것이 현실이다. 따라서 본 연구에서는 다중이용시설 묻지마 범죄 등의 위험성과 민간 경비원의 무기사용과 관련한 법제도적 한계점을 고찰하여, 이에 대한 개선방안을 제시하고자 한다.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.380-392
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• 2022

In this paper, the new vertiport regulations of the FAA and EASA are analyzed for urban air mobility(UAM), and the major components of the vertipad and the new specifications of each component are analyzed, and UAM operation in various environments is analyzed. Additional components for vertiport and regulations for surrounding airspace were also reviewed. Afterwards, based on the size of the S-A1 aircraft being developed by Hyundai Motors, domestic vertiport specifications and layouts were investigated for UAM operation, and these were applied to the city of Incheon. In addition, the time required for using a taxi or car were compared with the time required for using UAM between major locations in Incheon and Seoul.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.289-298
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• 2024

As digital mobile technology has advanced, vertical videos have emerged as a prominent format in the contemporary media field, presenting a new visual language that challenges traditional horizontal-centric aesthetic norms. This study delves into the visual and structural parallels and distinctions between traditional East Asian Hanging scrolls and contemporary vertical videos by applying traditional spatial composition techniques such as the 'Three Distances', 'One River, Two Banks', 'Intended Blank', and 'Unity of Poetry, Calligraphy, and Painting' to the creation of modern vertical videos. Through this comparative analysis, the research examines how vertical layouts enhance depth and layering of the screen, deepen emotional expression, and offer creators new avenues for expression. By juxtaposing the spatial compositions of traditional East Asian Hanging scrolls with those prevalent in today's digital vertical videos, this study seeks to uncover new visual languages and aesthetic values within the evolving media field.