• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.843-852
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• 2022

To determine the composition of benthic species on the southwest coast, a macrobenthos study was conducted at 18 sites on the islands of Wando and Jodo for seven summers (2014-2021) from June to September. Two hundred and twenty species(645 ind./m²) were collected on the rocky shores of Wando and Jodo. A similar number of species was observed in Wando (165 species) and Jodo (167 species). The mean density was higher in Wando (726 ind./m²) than in Jodo (564 ind./m²). The number of species was the highest at Site 15 (116 species), and the density was highest at Site 7 (1,664 ind/m²). The dominant species were Nodilittorina radiata with 175 ind./m² (27.1%), Littorina brevicula with 97 ind./m² (15.1%), and Heminerita japonica with 41 ind./m² (6.3%). The climate change indicator species, Tetraclita japonca, appeared in 15 sites, and the endemic species, Ptilohyale bisaeta, appeared in some sites. Fusinus spectrum, which appears on the Red List as a Near Threatened (NT) species, the lowest level of extinction risk, appeared in Jodo. The macrobenthos of Wando and Jodo demonstrated the general characteristics of rocky shores in Korea. Based on the tides and substrate, the rocky shores revealed a vertical distribution trend where Nodilittorina radiata, Littorina brevicula, Chthamalus challengeri, and Reishia clavigera were dominant. Wando and Jodo exhibited similar habitat distribution patterns.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.638-649
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• 2020

Purpose: The objective of this study is to evaluate the load carrying capacity of a target bridge structure based on the simple slab bridge of concrete over 20 years of public service. Method: By performing static loading test and dynamic loading test, the displacement, strain, impact factor, and natural frequency values were measured and evaluated through analysis method. Result: The main results of this study are as follows. First, the maximum displacement and maximum strain of S1 were assessed at 2.917 mm and 44.720 𝜇ε( tensile) and -13.760 𝜇ε(compression), respectively, with S2 maximum displacement and maximum strain being 2.100 mm and 4.870 𝜇ε(tensile), respectively. Second, the maximum measured impact factor was 0.191 in section S1 A-A, and the maximum measured impact factor was 0.155 in section S2 C-C. Third, the natural frequency was assessed at 6.086 Hz, and the measurement was found to be within the range of 6.152 Hz to 6.738 Hz. Conclusion: The tested bridge may be evaluated to show good behavior and characteristics for the design load.

• Journal of Broadcast Engineering
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• v.27 no.6
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• pp.848-859
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• 2022

This paper presents a novel 360-degree video streaming system for large-scale immersive displays and its ongoing implementation. Recent VR systems aim to provide a service for a single viewer on HMD. However, the proposed 360-degree video streaming system enables multiple viewers to explore immersive contents on a large-scale immersive display. The proposed 360-degree video streaming system is being developed in 3 research phases, with the final goal of providing 6DoF. Currently, the phase 1: implementation of the 3DoF 360-degree video streaming system prototype is finished. The implemented prototype employs subpicture-based viewport-dependent streaming technique, and it achieved bit-rate saving of about 80% and decoding speed up of 543% compared to the conventional viewport-independent streaming technique. Additionally, this paper demonstrated the implemented prototype on UCSB AlloSphere, the large-scale instrument for immersive media art exhibition.

• Quality Improvement in Health Care
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• v.28 no.1
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• pp.45-54
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• 2022

Purpose: The study aims to identify the theme list and priority criteria of patient safety theme reports in South Korea. Methods: The survey was conducted twice, and the importance of each criterion and theme was measured on a nine-point scale using the Delphi technique by a panel of 19 patient safety experts. The criteria included severity, universality, preventability, and organizational-social impact. Descriptive statistics such as frequency, percentage, mean, standard deviation, median, and interval quartile range were used to analyze the data. Results: The parameters were assigned a weighted average of 35% for severity, 20% for universality, 30% for preventability, and 15% for organizational-social impact, respectively. The final top three rankings were surgery safety, blood transfusion safety, and medication safety. In addition to expert opinion, for the theme that is selected based on the priority ranking, one to five sub-topics can be derived from the theme based on the priority ranking, societal demands, or the yearly priority list of patient safety incidents. Conclusion: It is recommended that the official patient safety center distribute the report in the form of a summary that can be utilized nationwide at medical institutions, government institutions, and other places. Updates, as well as accumulated theme reports, will serve as the baseline data for the proposal of the system and for the policy designed to implement and improve institutions' safety practices as a standard of domestic patient safety practice guidelines.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.5
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• pp.189-196
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• 2022

Skyline query is a scheme for exploring objects that are suitable for user preferences based on multiple attributes of objects. Existing skyline queries return search results as batch processing, but the need for real-time search results has increased with the advent of interactive apps or mobile environments. Online algorithm for Skyline improves the return speed of objects to explore preferred objects in real time. However, the object navigation process requires unnecessary navigation time due to repeated comparative operations. This paper proposes a Pre-processing Online Algorithm for Skyline Query (POA) to eliminate unnecessary search time in Online Algorithm exploration techniques and provide the results of skyline queries in real time. Proposed techniques use the concept of range-limiting to existing Online Algorithm to perform pretreatment and then eliminate repetitive rediscovering regions first. POAs showed improvement in standard distributions, bias distributions, positive correlations, and negative correlations of discrete data sets compared to Online Algorithm. The POAs used in this paper improve navigation performance by minimizing comparison targets for Online Algorithm, which will be a new criterion for rapid service to users in the face of increasing use of mobile devices.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.129-140
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• 2021

The next generation mBcN should be built to cooperate with the wireless network to support hyper-speed and hyper-connectivity. In this paper, we propose a network architecture for the cooperation mBcN and 5G commercial network and architecture of the cooperative security gateway required for the cooperation. The proposed cooperative security gateway is between gNB and UPF to support LBO, SFC, and security. Our analysis shows that the proposed architecture has several advantages. First of all, user equipment connected with the mBcN can be easily connected through the 5G commercial radio network to the mBcN. Second, the military application traffic can be transmitted to mBcN without going through the 5G core network, reducing the end-to-end transmission delay without causing the traffic load on the 5G core network. In addition, the security level of the military application can effectively be maintained because the user equipment can be connected to the cooperative security gateway, and the traffic generated by the user equipment is transmitted to the mBcN without going through the 5G core network. Finally, we demonstrate that LBO, SFC, and security modules are essential functions of the proposed gateway in the 5G test-bed environment.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.148-163
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• 2021

The diversification of the New Deal urban regeneration projects, that started in 2017 in accordance with the "Special Act on Urban Regeneration Activation and Support", generated the increased demand for the accuracy of data-driven diagnosis and project type forecast. Thus, this research was conducted to develop an application model able to identify the most appropriate New Deal project type for "eup", "myeon" and "dong" across the country. Data for application model development were collected through Statistical geographic information service(SGIS) and the 'Urban Regeneration Comprehensive Information Open System' of the Urban Regeneration Information System, and data for the analysis model was constructed through data pre-processing. Four models were derived and simulations were performed through polynomial regression analysis and multinomial logistic regression analysis for the application of the appropriate New Deal project type. I verified the applicability and validity of the four models by the comparative analysis of spatial distribution of the previously selected New Deal projects by targeting the sites located in Seoul by each model and the result showed that the DI-54 model had the highest concordance rate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.73-81
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• 2022

Recently, as the service life of structures increased, the load-carrying capacity of deteriorated reinforced concrete, where corrosion of reinforcing bars occurs due to various causes, is frequently decreased. In order to address this problem, many studies on the bond characteristic of FRP (Fiber Reinforced Polymer) bars with corrosion resistance, light weight and high tensile strength have been conducted, however there are not many studies on the bond characteristic of grid-typed CFRP embedded in concrete. Therefore, in order to evaluate the bond characteristics of grid-typed CFRP and its usability as a substitute for steel rebar, a pull-out test is performed using the longitudinal bond length and transverse grid length of the grid-typed CFRP as variables. Through the pull-out test, the bond load-slip curve of the grid-typed CFRP is derived, and the bond behavior is analyzed. The total bond load equation is proposed as the sum of the bond force of the longitudinal bond length and the shear force of the grid in the transverse direction. Also, expressing the area of the bond load-slip curve as total work, the change in dissipated energy with respect to the slip is analyzed to examine the effect of the tranverse grid on the bond force.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.230-237
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• 2022

It is essential that service life of reinforced concrete structures in economic and safety aspects should be secured. It is well-known that chloride attack is a typical deterioration mechanism in field concrete structures. To prevent serious accidents like collapse, many studies have been conducted to increase resistance of chloride ingress using concrete mixed with GGBS. The usage of GGBS concrete is nowadays mandatory. Since most concretes in the field are unsaturated, study regarding chloride absorption is necessary, but many studies have focused on the chloride diffusion phenomenon. Methods for evaluating chloride absorption are cost and improper in the field. It is necessary to develop a simple method for evaluating chloride absorption in practice. This study evaluated resistance of chloride ingress in GGBS concretes with impedance measurement and absorption test. From the results, it was confirmed that the contents of absorbed chloride were linearly correlated with the measured electrical resistivities (or conductivities) in the concrete. At the end of the test, the electrical conductivities were 250.8 S/m (w/b=0.4) and 303.1 S/m (w/b=0.6) for PC concretes, and 2.6 S/m (w/b=0.4) and 64.4 S/m (w/b=0.6) for GGBS concretes, respectively. Considering influencing factors for chloride absorption and impedance measurement, chloride ingress into concrete is mainly affected by pore structures due to replacement of GGBS. Especially, formations of pore structure are different with binder, thereby binders should be considered in building reinforced concrete structures exposed to chloride environments.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.515-524
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• 2022

The turnout system of the sleeper floating tracks (STEDEF) on urban transit is a Anti-vibration track composed of a wooden sleeper embedded in a concrete bed and a sleeper resilience pad under the sleeper. Therefore, deterioration and changes in spring stiffness of the sleeper resilience pad could be cause changes in sleeper support conditions. The damage amount of manganese crossings that occurred during the current service period of about 21 years was investigated to be about 17% of the total amount of crossings, and it was analyzed that the damage amount increased after 15 years of use (accumulated passing tonnage of about 550 million tons). In this study, parameter analysis (wheel position, sleeper support condition, and dynamic wheel load) was performed using a three-dimensional numerical model that simulated real manganese crossing and wheel profile, to analyze the damage type and cause of manganese crossing that occurred in the actual field. As a result of this study, when the voided sleeper occurred in the sleeper around the nose, the stress generated in the crossing nose exceeded the yield strength according to the dynamic wheel load considering the design track impact factor. In addition, the analysis results were evaluated to be in good agreement with the location of damage that occurred in the actual field. Therefore, in order to minimize the damage of the manganese crossing, it is necessary to keep the sleeper support condition around the nose part constant. In addition, by considering the uniformity of the boundary conditions under the sleepers, it was analyzed that it would be advantageous to to replace the sleeper resilience pad together when replacing the damaged manganese crossing.