• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• 제7권5호
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• pp.961-969
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• 2017

Today, the world is experiencing a variety of natural disasters due to the extreme weather. Drought that occurred throughout Southeast Asia from February to May 2016 is also a form of abnormal climate. As a result of this drought, five countries, including Cambodia, Thailand, Vietnam, Laos and Myanmar, faced food shortages, food shortages, as well as rice yields for export. In this study, remote sensing technique was applied to the vicinity of Tonlé Sap, the largest lake in Southeast Asia, to quantitatively analyze the damage caused by drought. As a result, the change of land cover caused a drastic decrease in the water system (132.582㎢) and greenery (706.937㎢) in February 2016, and the reduced water system and greenery changed to dry land and paddy field. It was also found that the temperature rise of 6℃ ~ 8 ℃ compared to the previous year due to the drought from February to April 2016 due to the change of the surface temperature. And it was found that the function of the lake was deteriorated in April due to continuous drought.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• 제7권5호
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• pp.83-92
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• 2017

Because the exhibition space in the virtual reality is another kind of reality, which exits in another level, it enables us free from time and physical space, so using the virtual reality will be an effective practice for overcoming cultural divide and managing museums. Especially, virtual reality could transform a fixed physical space into portable contents, so this characteristic would be useful and meaningful when applying the outreach program, which claimed to stand for 'museum out of museum' as following. First, it will give more opportunities of experiencing museums to many people because of freedom of physical space, one of the advantages virtual reality has. Second, people will experience and understand the contents under the context, rather than simply exposing information of artifacts one by one. Third, even people who are far from a museum can experience identical contents at the same time, so this synchronicity will enhance communications among people and the society. Fourth, it will provide rich contents to people by putting a variety of exhibitions into one VR device. Fifth, it will be useful for archiving the exhibition with minimizing the loss of contents. Sixth, VR will convert museum visitors from observers to operators. Finally, VR can expand the target audience of the outreach program and develop a variety of education programs. Because museums is a public organization for overcoming cultural divide and enhancing communication, they should adopt virtual reality, which enables to extend the exhibition space and provide more opportunities of experiencing museums.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제26권11호
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• pp.1577-1585
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• 2022

As the interest in the 4th industrial revolution and metaverse increases, metaverse with multi edge structure is proposed and noted. Metaverse is a structure that can create digital doctor-like system through a large amount of image processing and data transmission in a multi edge system. Since metaverse application requires calculating performance, which can reconstruct 3-D space, edge hardware's insufficient calculating performance has been a problem. To provide streamable AI software in runtime, image processing, and data transmission, which is edge's loads, needs to be lightweight. Also lightweight at the edge leads to power consumption reduction of the entire metaverse application system. In this paper, we propose collaborative edge-cloud image processing with remote image processing method and Region of Interest (ROI) to overcome edge's power performance and build streamable and runtime executable AI software. The proposed structure was implemented using a PC and an embedded board, and the reduction of time, power, and network communications were verified.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제33권6호
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• pp.1077-1086
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• 2023

The searchable encryption model allows to selectively search for encrypted data stored on a remote server. In a real-world scenarios, the model must be able to support multiple search keywords, multiple data owners/users. In this paper, these models are referred to as Multi Ranked Searchable Encryption model. However, at the time this paper was written, the proposed models use fully-trusted trapdoor centers, some of which assume that the connection between the user and the trapdoor center is secure, which is unlikely that such assumptions will be kept in real life. In order to improve the practicality and security of these searchable encryption models, this paper proposes a new Multi Ranked Searchable Encryption model which uses random keywords to protect search words requested by the data downloader from an honest-but-curious trapdoor center with an external attacker without the assumptions. The attacker cannot distinguish whether two different search requests contain the same search keywords. In addition, experiments demonstrate that the proposed model achieves reasonable performance, even considering the overhead caused by adding this protection process.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• 제16권6호
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• pp.519-525
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• 2023

The human brain constantly emits electrical impulses, which is called brain waves, and brain waves can be defined as the electrical activity of the brain generated by the flow of ions generated by the biochemical interaction of brain cells. There is a study that emotion is one of the factors that can cause stress. Brain waves are the most used in the study of emotions. This paper is a study on whether emotions affect stress, and showed two images of fear and joy to four experimenters and divided them into three stages before, during, and after watching. As a measurement tool, brain waves at the positions of Fp1 and Fp2 were measured using the NeuroBrain System, a system that can automate brain wave measurement, analysis, brain wave reinforcement, and suppression training with remote control. After obtaining the brain wave data for each emotion, the average value was calculated and the study was conducted. As for the frequency related to stress, the values of Alpha and SMR, Low Beta, and High Beta were analyzed. Brainwave analysis affects stress depending on the emotional state, and "fear" emotions cause anxiety by raising Beta levels, resulting in higher Mind Stress levels, while "joy" emotions lower Beta levels, resulting in a significant drop in Mind Stress.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• 제16권6호
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• pp.478-488
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• 2023

This paper investigates the naval application of laser communication as a potential replacement for traditional acoustic wave communication in underwater environments. We developed a laser transceiver using Arduino and MATLAB, conducting a water tank experiment to validate communication feasibility across diverse underwater conditions. In the first experiment, when transmitting data through a laser, the desired message was converted into data and transmitted, received, and confirmed to be converted into the correct message. In the second experiment, the operation of communication in underwater situations was confirmed, and in the third experiment, the intensity of light was measured using the CDS illuminance sensor module and the limits of laser communication were measured and confirmed in various underwater situations. Additionally, MATLAB code was employed to gather data on salinity, water temperature, and water depth for calculating turbidity. Optimal wavelength values (532nm, 633nm, 785nm, 1064nm) corresponding to calculated turbidity levels (5, 20, 55, 180) were determined and presented. The study then focuses on analyzing potential applications in naval tactical communication, remote sensing, and underwater drone control. Finally, we propose measures for overcoming current technological limitations and enhancing performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제24권1호
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• pp.207-212
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• 2024

The importance of hydrogen fuel cells continues to be emphasized, and there is a growing demand for education and training in this field. Among various educational environments, metaverse education is opening a new era of change in the global education industry, especially to adapt to remote learning. The most significant change that the metaverse has brought to education is the shift from one-way, instructor-centered, and static teaching approaches to multi-directional and dynamic ones. It is expected that the metaverse can be effectively utilized in hydrogen fuel cell engineer education, not only enhancing the effectiveness of education by enabling learning and training anytime, anywhere but also reducing costs associated with engineering education.In this research, inspired by these ideas, we are designing a fuel cell education platform. We have created a platform that combines theoretical and practical training using the metaverse. Key aspects of this research include the development of educational training content to increase learner engagement, the configuration of user interfaces for improved usability, the creation of environments for interacting with objects in the virtual world, and support for convergence services in the form of digital twins.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제24권3호
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• pp.27-34
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• 2024

The direct and indirect damages caused by fires in underground utility tunnels have a great impact on society as a whole, so efforts are needed to prevent and manage them in advance. To this end, research is ongoing to prevent disasters such as fire flooding by applying digital twin technology to underground utility tunnels. A network is required to transmit the sensed signals from each sensor to the platform. In essence, it is necessary to analyze the application of wireless networks in the underground utility tunnel environments because the tunnel lacks the reception range of external wireless communication systems. Within the underground utility tunnels, electromagnetic interference caused by transmission and distribution cables, and diffuse reflection of signals from internal structures, obstacles, and metallic pipes such as water pipes can cause distortion or size reduction of wireless signals. To ensure real-time connectivity for remote surveillance and monitoring tasks through sensing, it is necessary to measure and analyze the wireless coverage in underground utility tunnels. Therefore, in order to build a wireless network environment in the underground utility tunnels. this study minimized the shaded area and measured the actual cavity environment so that there is no problem in connecting to the wireless environment inside the underground utility tunnels. We analyzed the data transmission rate, signal strength, and signal-to-noise ratio for each section of the terrain of the underground utility tunnels. The obtained results provide an appropriate wireless planning approach for installing wireless networks in underground utility tunnels.

• The Journal of the Korean bone and joint tumor society
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• 제14권1호
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• pp.33-43
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• 2008

Purpose: To evaluate the clinical usability of reconstructive methods, and how to select flap after wide excision of malignant soft tissue tumor in ankle and foot. Materials and Methods: The 15 cases shown in the 14 patients (In case of a male patient, reconstruction was performed two times due to local recurrence.) with malignant soft tissue tumor in ankle and foot, who underwent reconstruction after wide excision from March 2000 until March 2007. Oncologic, surgical and functional results were evaluated. Results: The method of reconstruction used were anterolateral thigh perforator flap (5cases), Reversed superficial sural artery flap (4 cases), dorsalis pedis flap (3 cases), local flap (3cases). The defect, mean size was $5.5{\times}5.7\;cm$, was reconstructed with rotation flap or free flap, mean size was $5.9{\times}6.0\;cm$, skin graft for remnant. The mean operation time was 310 minutes (120~540 minutes); it took 256 minutes to reconstruct by rotation flap, and 420 minutes by free flap. As oncologic results, 7 patients were no evidence of disease, 6 patients were alive with disease and 1 patient was expired by pulmonary metastasis at the time of the last follow-up. 4 patients had local recurrence and 4 pateints had distant metastases. As functional results, 14 patients were evaluated with average score of 68.8% using the system of the Musculoskeletal Tumor Society. Conclusion: The dorsalis pedis and reverse superficial sural artery rotation flap which is easy procedure, has less complication and takes short operation time, can be primarily considered to reconstruct a small defect. And the anterolateral thigh perforator flap is suitable for coverage of a large defects after wide excision of malignant soft tissue tumor in ankle and foot.

• Journal of Yeungnam Medical Science
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• 제16권1호
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• pp.94-100
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• 1999

The aim of this retrospective study was to determine whether a nephron sparing surgery might be feasible in patients with a small solid renal tumor. Materials and methods: Between 1988 and 1999, 21 patients with a radiologically detectable small solid renal tumor underwent enucleoresection, wedge resection and polar segmental nephrectomy. The mean age of the 11 men and 10 women in this study was 43 years (range 14 to 68). According to the preoperative radiological diagnosis, 15 among the 21 patients were considered to have renal cell carcinoma, 4 were considered to have angiomyolipoma, and in the remaining 2 patients, radiological differentiation of renal tumors was difficult. Among 15 patients considered to have renal cell carcinoma, 14 were found to have renal cell carcinoma and the remaining one patient was diagnosed as having oncocytoma on pathologic examination. Radiological determination of angiomyolipoma in four patients was confirmed to be correct on pathological examination. The 2 patients whose radiological diagnose was difficult were found to have cavernous hemangioma and angiomyolipoma. One patient with renal cell carcinoma developed arteriocaliceal fistula, the only immediate complication in this series and underwent nephrectomy on postoperative 10th day. The mean follow up duration for the 14 patients with renal cell carcinoma was 18.6 months (range:1-103). There was no other tumor involvement in the resection margins following the nephron sparing surgery. These results suggest that nephron sparing surgery provides an effective treatment for patients with a single, small, unilateral, localized renal tumor. Longer follow-up is suggested for more definite verification of the role of nephron sparing surgery.