• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.177-182
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• 2024

In this paper, the purpose of this paper is to predict and prevent the risk of crowd concentration in advance for possible future crowd accidents based on the Itaewon crush accident in Korea on October 29, 2022. In the case of a single CCTV, the administrator can determine the current situation in real time, but since the screen cannot be seen throughout the day, objects are detected using YOLOv4, which learns images taken with CCTV angle, and safety accidents due to crowd concentration are prevented by notification when the number of clusters exceeds. The reason for using the YOLO v4 model is that it improves with higher accuracy and faster speed than the previous YOLO model, making object detection techniques easier. This service will go through the process of testing with CCTV image data registered on the AI-Hub site. Currently, CCTVs have increased exponentially in Korea, and if they are applied to actual CCTVs, it is expected that various accidents, including accidents caused by crowd concentration in the future, can be prevented.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.1
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• pp.57-70
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• 2024

In order to present a predictive drift model, Jeju National University's training ship was tested for about 11 hours and 40 minutes, and 81 samples that selected one of the entire samples at ten-minute intervals were subjected to regression analysis after verifying outliers and influence points. In the outlier and influence point analysis, although there is a part where the wind direction exceeds 1 in the DFBETAS (difference in Betas) value, the CV (cumulative variable) value is 6%, close to 1. Therefore, it was judged that there would be no problem in conducting multiple regression analyses on samples. The standard regression coefficient showed how much current and wind affect the dependent variable. It showed that current speed and direction were the most important variables for drift speed and direction, with values of 47.1% and 58.1%, respectively. The analysis showed that the statistical values indicated the fit of the model at the significance level of 0.05 for multiple regression analysis. The multiple correlation coefficients indicating the degree of influence on the dependent variable were 83.2% and 89.0%, respectively. The determination of coefficients were 69.3% and 79.3%, and the adjusted determination of coefficients were 67.6% and 78.3%, respectively. In this study, a more quantitative prediction model will be presented because it is performed after identifying outliers and influence points of sample data before multiple regression analysis. Therefore, many studies will be active in the future by combining them.

• Journal of Environmental Science International
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• v.33 no.3
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• pp.193-203
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• 2024

This study aims to determine the factors affecting the level of satisfaction with the Cell Broadcast Service (CBS) among citizens in Incheon. Partial least squares (PLS) regression, instead of multiple regression, was used for the analysis because it can solve multicollinearity and sample size issues. The analysis results are as follows: The factor with the greatest effect on satisfaction with CBS among Incheon citizens, was the elimination of redundancies (VIP=1.185). Therefore, local governments, government agencies, and public organizations must coordinate their ideas and collectively create guidelines to eliminate redundancies. The second most influential factor was the expansion in the broadcast medium from legal, institutional, and policy aspects (VIP=1.087). This is because differences in generation, age, gender, and personal characteristics were not considered. Therefore, it is necessary to devise a customized messaging tool through the expansion of broadcast media. The broadcast criteria of the legal, institutional, and policy perspectives comprised the third most influential factor, with a high VIP value of 1.053. Consequently, it is essential to devise a plan to avoid distributing unnecessary cell broadcast services, by establishing criteria for areas and sections, time, and the direct and indirect impact zones of a disaster. In the future, this study could be used as base data to develop policies, guidelines, and response measures for Incheon CBS. Given the lack of research on the diverse characteristics of each social class and the city traits of each region, and a lack of concrete empirical research on each factor, continuous and in-depth studies are required in the future.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.885-890
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• 2024

This study proposes a secure keypad structure that can adapt to screen changes in mobile devices equipped with stretchable display. For this purpose, we compared and analyzed the authentication methods applied to current rigid form factor smartphones with those applied to rollable and bendable display based smartphones, which are the previous stages of stretchable display. Based on the results of this analysis, we identified potential user convenience and security safety issues that may arise in the form factor structure for smart wallets, multitasking, screen expansion and media viewing, and gaming and entertainment applications where stretchable displays will be applied, then proposed a security keypad structure for these form factors. Our keypad structure provides enhanced user convenience and security compared to the structures applied in the smartphone environment based on the conventional rigid display form factor and rollable, bendable display form factor.

• The Transactions of the Korea Information Processing Society
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• v.13 no.7
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• pp.319-325
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• 2024

This study aims to develop a mobile application for the care of panic disorder, assisting in the prevention of panic attacks and the management of symptoms. Panic disorder is a psychological condition characterized by persistent fear, anxiety, and panic attacks, which requires appropriate treatment and management. The increasing need for digital therapeutics that users can access without time and space constraints is evident. The application developed through this research provides basic knowledge about panic disorder, enables self-diagnosis to monitor one's condition, and offers various therapeutic methods to effectively aid in the care of panic disorder. Additionally, it provides notifications based on real-time user location when they reach places where they have previously experienced panic attacks, and offers personalized support. This digital therapeutic aims to introduce new tools and treatment methods beyond traditional therapies. Furthermore, it is expected to contribute positively by promoting the use of digital therapeutics not only for panic disorder but also across the entire field of mental health, thereby improving users' quality of life.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.833-840
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• 2024

According to recent data from the Korea Meteorological Administration(KMA), the frequency of typhoons around the Korea Peninsula is almost unchanged, but the intensity is on the rise due to climate change. A typhoon that has become so powerful can cause partial or complete damage to the traffic signal structures, limiting the operation of the vehicle and causing traffic congestion. If the traffic signal structure fails to function properly due to the influence of the typhoon, not only the v ehicle operation will be disrupted, but also direct damage to the traffic signal structure will occur. In addition, if the social overhead cost of traffic congestion is included, the recovery cost caused by the typhoon will increase to an extent that it is difficult to estimate. Therefore, in this study, a wind tunnel experiment was performed by producing a wind tunnel model of an existing fixed traffic signal structure and a traffic signal structure in which signs and traffic lights are hinged. Also, The fixed and hinge structures were modeled as 3D finite elements, and wind-resistant analysis was performed by wind speed, and, wind-resistant safety of traffic signal structures were analyzed and examined through wind-resistant analyses. From the comparative analysis of the results of experiment and FE analysis, it was known that the stress reduction rate of the hinge connection structure was at least 30% compared to that of the fixed connection structure from the results of the wind tunnel experiment and FE analysis. And As a result of finite element analysis for the maximum design wind speed of 50m/s, it was found that the maximum stress generated in the existing structure exceeded all the yield stress, but the maximum stress of the hinge connection structure was within the yield stress. Finally The hinge connection structure showed a relatively large stress reduction rate as the wind speed increased and the length of the lateral beam was shorter at the same wind speed.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.20 no.1
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• pp.1-7
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• 2024

To In this study, a nozzle which is designed to work as expansion device was installed in a refrigeration system and performance test was conducted. The nozzle has 0.8mm, 1.0mm, 1.2mm diameter and inserted in a body of the devices. System performance was compared with a electronic expansion device(EEV, electric expansion valve) and designed nozzles at the environmental conditions such as dry bulb and wet bulb temperature. To reduce energy loss in the evaporator, a nozzle was inserted into the evaporator. In the comparison test, the opening of the EEV was adjusted to the same diameter as the 3 nozzles, and the experiments conducted at a 27℃ dry bulb temperature and 19.5℃ wet bulb temperature with 50% relative humidity as defined at KS C 9306 standard. To find out the effect of the environmental condition, the bulb temperature was varied 5 degree lower and higher than the standard condition temperature with the same relative humidity condition at 50%. The air flow rate to the evaporator was also changed 4, 7 and 10 m³/min. As results, the temperature drop in the nozzle was 153% higher than that of the EEV and the enhancement of the performance(COP) was up to 125.7% if install the nozzles in the refrigeration system. The highest performance was obatained at 1.0mm diameter nozzle.

• Journal of Korea Port Economic Association
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• v.40 no.2
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• pp.1-20
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• 2024

The purpose of this study is to clarify a safety efficiency of ports in South Korea considering port casualties. The paper conducted a vector auto regression to analyze a cause-and-effect relationship between latent factors and port casualties. Subsequently, the paper evaluated safety efficiency for the ports using an undesirable outputs model. The results implied that the number of workers in the shipping union had a statistical effect on the port casualties. In contrast, the number of workers in the operators and working hours are unrelated to the port casualties. In addition, it was found that Yeosu Gwangyang Port is the most safety efficiency port in South Korea. Based on these results, this paper may provide various policy implications for port operators, developers, and managers.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.1
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• pp.103-109
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• 2009

Analysis of collection factor was studied to compare various parameters such as collection time, transport time, amount of collection and number of man power by on-the-spot survey at one municipal area and one rural area in Jeju-do. Results showed that the amount of man and time to collect 1 ton of waste of rural area($5.853man{\cdot}hour\;per\;time$) was four times as much as that of municipal area($1.527man{\cdot}hour\;per\;time$). In case of a transport time, rural area(11.08 per km/hr) has similar value to municipal area(11.07 per km/hr) and has half or one third value to the restaurant(36.7km/hr), an apartment area(33.0km/hr) and a detached area(22.4km/hr).

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.37-50
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• 2009

This study was carried out to investigate the integrated biomass strategies for utilization and application characteristics in Hokkaido prefecture, japan. From the results, to achieve a successful operation of biomass recycling facilities, it previously needs the effective byproduct supplying construction system for field demander as well as the advanced environmental technology introduction. Especially, the value-promotion recycling technology were requested as follows; (1) production of functional solid composting for protection soil acidification, (2) the addition of soil microorganism to the production of liquid fermentation fertilizer, (3) construction of diverse energy supply system, (4) mixed organic material fermentation process concerning on heavy metal concentration, (5) introduction of incentive garbage collection system for contaminants prevention.