• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.683-689
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• 2019

We are trying to evaluate usefulness of Wide Coverage Volume Axial Mode by comparing and analyzing for exposure doses to patients and video quality extracted from two materials. First material is a computer tomography scanning of paediatric cardiac made by using High Pitch Mode, which is designed for diagnosing Congenital cardiac diseases. Second material is computer tomography scanning of paediatric cardiac made by using Wide Coverage Volume Axial Mode. When we did computer tomography scanning of paediatric cardiac, we used High Pitch Mode and Wide Coverage Volume Axial Mode to 50 patients of each, overall 100 patients. Also, we compared exposure doses to patients using videos got from each protocol. Then we compared video quality by calculating SNR and CNR by setting ROI of each. Not only exposure doses to patients were reduced by 13.07 %, but also SNR and CNR were improved when testing used Wide Coverage Volume Axial Mode rather than using High Pitch Mode. Wide Coverage Volume Axial Mode reduced testing time by using high-speed scanner. Furthermore, we can find out that Wide Coverage Volume Axial Mode is an useful method through improving video quality and reducing exposure doses to patients than using High Pitch Mode from ASiR-V, which is low-dose technology.

• Journal of Internet Computing and Services
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• v.20 no.5
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• pp.105-111
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• 2019

Core technologies that lead the Fourth Industrial Revolution era, such as artificial intelligence, big data, and autonomous driving, are implemented and serviced through the rapid development of computing power and hyper-connected networks based on the Internet of Things. In this paper, we implement two different models for drivable area segmentation in various environment, and propose a better model by comparing the results. The models for drivable area segmentation are using DeepLab V3+ and Mask R-CNN, which have great performances in the field of image segmentation and are used in many studies in autonomous driving technology. For driving information in various environment, we use BDD dataset which provides driving videos and images in various weather conditions and day&night time. The result of two different models shows that Mask R-CNN has higher performance with 68.33% IoU than DeepLab V3+ with 48.97% IoU. In addition, the result of visual inspection of drivable area segmentation on driving image, the accuracy of Mask R-CNN is 83% and DeepLab V3+ is 69%. It indicates Mask R-CNN is more efficient than DeepLab V3+ in drivable area segmentation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.3-12
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• 2005

This paper introduces a 3D perceptual model based on JND(Just Noticeable Difference) and proposes a video watermarking scheme which is perceptual approach of adaptive embedding in 3D-DCT domain. Videos are composed of consecutive frames with many similar adjacent frames. If a watermark is embedded in the period of similar frames with little motion, it can be easily noticed by human eyes. Therefore, for the transparency the watermark should be embedded into some places where motions exist and for the robustness its magnitude needs to be adjusted properly. For the transparency and the robustness, watermark based on 3D perceptual model is utilized. That is. the sensitivities from the 3D-DCT quantization are derived based on 3D perceptual model, and the sensitivities of the regions having more local motion than global motion are adjusted. Then the watermark is embedded into visually significant coefficients in proportion to the strength of motion in 3D-DCT domain. Experimental results show that the proposed scheme improves the robustness to MPEG compression and temporal attacks by about $3{\sim}9\%$, compared to the existing 3D-DCT based method. In terms of PSNR, the proposed method is similar to the existing method, but JND guarantees the transparency of watermark.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.217-226
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• 2021

The use of personal mobility(PM) is increasing because of preading shared mobility, but, it causes risk of accidents and fear to pedestrians because of lack of sound. The purpose of this study is to find out the effects of the alert sound in PM and driving direction on risk perception of pedestrians, awareness on PM driver, and allowance for driving on each road. The 8 videos were produced from a pedestrian perspective, depending on the alert sound type(silent, vess, bell, voice) and direction of driving(front, back). After watching each video, participants completed surveys. There was a non-effect on the driving direction. Regardless of the alert sound type, all of the sounds reduced the risk perception. Also, the awareness of PM drivers and allowance for driving on each road were positive. This study found that PM needed an alert sound for pedestrian safety. We expect the results of the study to help improve awareness of PM and make policies and regulations.

• Korean Journal of Heritage: History & Science
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• v.55 no.1
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• pp.5-34
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• 2022

The purpose of this study is to investigate the unique contrasting landscape characteristics of imperial tombs of Qing dynasty by examining the characteristics of facility layout in which location, Feng shui, and siblings are harmonized with the 12 Qing Dynasty Hwanggyeongchim. Through literature surveys, field observation and interviews, videos and drawing comparison, and inductive contrast analysis, the contrasting landscape characteristics of imperial tombs in the Qing Dynasty were analyzed by classifying them into natural environment, location, Feng shui, and formal esthetics. As a result, the characteristics of the location type and the layout plan of the Qing dynasty imperial tombs were derived from the analysis of Feng shui shape, axis extension distance along the midaxial line, the width of the ridge, the formality of the facility layout according to the difference between the height of the starting point and the end point, the leftward direction of the tomb, and the space ratio of the 'entry space' - 'ritual space' - 'burial mound space', etc. In addition, it was possible to derive the facility arrangement characteristics of tombstones through the analysis of the types and the arrangement order of tombs facilities, as well as the distribution, quantity and types of stone figures, while also revealing some contrasting characteristics different from those of the Ming Dynasty. In addition, it was confirmed that the spatial division effect through the water system and the view effect of the view from the midaxial line and the vista are the representative view effect found in the Qing Dynasty imperial tombs along with the density contrast.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.235-242
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• 2022

The purpose of this study is to propose an effective class of College English, one of the essential liberal arts subjects of S University, and to analyze the learning effect. This subject targets students with different majors in the first grade, and the learning goal is to improve their reading skills by analyzing students' English skills, especially sentences, as grammatical elements in everyday situations. This thesis examines how College English classes can be conducted in the form of convergence class in the COVID-19 era to induce students' learning motivation and create learning effects. The form of this convergence class is as follows. First, lecture videos, second, Webex real-time non-face-to-face classes, and third, face-to-face classes. In this study, the class procedure of the first class among the classes that were actually conducted during the semester was presented as an example. The researcher specifically surveyed the pre-class questionnaire and conducted the class by grasping the students' English skills and characteristics of the learners through the results. And after taking the course, the questionnaire was surveyed into 30 items and the results were analyzed. Specifically, the results of satisfaction with the composition of the lecture, satisfaction with the lecture video, satisfaction with the face-to-face class, interaction with students, and learning effects were analyzed. This class proposal is a learner-centered model in the form of convergence.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.69-75
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• 2022

The purpose of this study is to present the direction of the development and utilization of remote class content for infants in a future educational environment through the analysis of remote class content for childhood. The analysis targets are 148 kindergarten [play ON] contents, and the analysis results according to "easy to use," "interest," "educational," "conformity of content," and "technicality" are as follows. Except for the 'conformity of content', there was a large variation in the score of content for each sub-area. In the case of "conformity of content," almost all of them received high scores for content production by incumbent teachers. With this in mind, we have drawn the following conclusions: First, it should be produced at an appropriate speed in consideration of the induction and understanding of childhoods' participation in play in the search and progress process, and it should be possible to play according to the challenges and levels using various strategies under the theme that all childhoods can be interested in. In addition, it was found that it was necessary to select topics, edit videos, and voice support so that childhoods can participate in the process of discovery and search, supporting childhoods' imagination, curiosity, and creative experiences.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.115-121
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• 2022

As city environments have recently become crowded, there are many obstacles that interfere with the walking of the visually impaired on pedestrian roads. Typical examples include ballads, parking breakers and standing signs, which usually do not get in the way, but blind people may be injured by collisions. To solve such a problem, many solutions have been proposed, but they are limited in applied in practical environments due to the several restrictions such as outside use only, inaccurate obstacle sensing and requirement of special devices. In this paper, we propose a new method to automatically detect obstacles while walking on the pedestrian roads and warn the collision risk in advance by using only sensors embedded in typical mobile phones. The proposed method supports the walking of the visually impaired by notifying the type of obstacles appearing in front of them as well as the distance remaining from the obstacles. To accomplish this goal, we utilized an object recognition technology applying the latest deep learning algorithms in order to identify the obstacles appeared in real-time videos. In addition, we also calculate the distance to the obstacles using the number of steps and the pedestrian's stride. Compared to the existing walking support technologies for the visually impaired, our proposed method ensures efficient and safe walking with only simple devices regardless of the places.

• Korean Journal of Remote Sensing
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• v.38 no.3
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• pp.237-250
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• 2022

In this study, we propose a method to estimate the biomass of invertebrate grazers from the videos with underwater drones by using a multi-object tracking model based on deep learning. In order to detect invertebrate grazers by classes, we used YOLOv5 (You Only Look Once version 5). For biomass estimation we used DeepSORT (Deep Simple Online and real-time tracking). The performance of each model was evaluated on a workstation with a GPU accelerator. YOLOv5 averaged 0.9 or more mean Average Precision (mAP), and we confirmed it shows about 59 fps at 4 k resolution when using YOLOv5s model and DeepSORT algorithm. Applying the proposed method in the field, there was a tendency to be overestimated by about 28%, but it was confirmed that the level of error was low compared to the biomass estimation using object detection model only. A follow-up study is needed to improve the accuracy for the cases where frame images go out of focus continuously or underwater drones turn rapidly. However,should these issues be improved, it can be utilized in the production of decision support data in the field of invertebrate grazers control and monitoring in the future.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.217-227
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• 2021

The study aims to explore the rapidly changing university sports-related lecture environment from the perspective of professors and seek comprehensive and practical improvements in the online lecture environment for both professors and learners. In order to achieve the purpose of this study, six professors related to physical education at the university were selected as research participants, and in-depth interviews were used for about four months from September 2020 to December 2020. Examples of the problems, counterplans, and the improvement plans of professors who related to sports were shown as the results. First, the difficulties faced by professors have been divided into online and offline lecture problems, which are Internet and media possession, online lecture place amulet, professor-learner communication disorder, attendance verification and evaluation, COVID-19 infection, and face-to-face lecture place restriction since the outbreak of COVID-19. Second, professors' response to online and offline lecture problems was diversification of communication media, telecommuting, providing online learning videos, replacing and reinforcing practical classes, which were found to be somewhat lacking in government and school support systems. Finally, since the COVID-19 outbreak, Sports-related lecture's continuous problems and the professor's responses require the improvements such as government-level guidelines, university-level expansion of the venues for on- and off-line lecture, devising online lecture programs that enhance professor's convenience, and adjusting the number of participants for on- and off-line lecture.