• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.19-31
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• 2023

According to the climate change scenarios, the intensity of typhoons, a major factor in Korea's natural disaster, is expected to increase. The increase in typhoon intensity leads to a rise in wave heights, which is likely to cause large-scale disasters in coastal regions with high populations and building density for dwelling, industry, and tourism. This study, therefore, analyzed observation data of the Donghae ocean data buoy and conducted a numerical model simulation for wave estimations for the typhoon MAYSAK (202009) period, which showed the maximum significant wave height. The boundary conditions for wave simulations were a JMA-MSM wind field and a wind field applying the typhoon central pressure reduction rate in the SSP5-8.5 climate change scenario. As a result of the wave simulations, the wave height in front of the breakwater at Sokcho port was increased by 15.27% from 4.06 m to 4.68 m in the SSP5-8.5 scenario. Furthermore, the return period at the location of 147-2 grid point of deep-sea design wave was calculated to increase at least twice, it is necessary to improve the deep-sea design wave of return period of 50-year, which is prescriptively applied when designing coastal structures.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.1
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• pp.1-10
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• 2015

In the safety assessment of the geological disposal system of the radioactive wastes, the abnormal scenarios, in which the system is impacted by the abnormal events, need to be considered in addition to the reference scenario. In this study, characterization and prediction of well intrusion as one of the abnormal events which will impact the disposal system were conducted probabilistically and statistically for the safety assessment. The domestic well development data were analyzed, and the prediction methodologies of the well intrusion were suggested with a computation example. From the results, the annual well development rate per unit area in Korea was about 0.8 well/yr/km² in the conservative point of view. Considering the area of the overall disposal system which is about 1.5 km², the annual well development rate within the disposal system could be 1.2 well/yr. That is, it could be expected that more than one well would be installed within the disposal system every year after the institutional management period. From the statistical analysis, the probabilistic distribution of the well depth followed the log-normal distribution with 3.0363 m of mean value and 1.1467 m of standard deviation. This study will be followed by the study about the impacts of the well intrusion on the geological disposal system, and the both studies will contribute to the increased reliability of safety assessment.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.781-795
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• 2008

This paper focuses on effects that IPTV will have on domestic broadcasting market in the point of view of customers. The purpose of the paper is to present the future landscape of competitive media market when IPTV is launched, and to research how IPTV will have impact on terrestrial broadcasting, cable TV and satellite broadcasting industry. The paper integrates two known theories, such as the niche-gratification model and the value-expectancy model, to analyze competitive media market. The value expected model makes it possible to overcome the weakness of the niche-gratification model and to forecast competitiveness more accurately. According to this research, competitive power will be in the order of Cable TV, IPTV, and satellite broadcasting. Terrestrial broadcasting does not show strong competitive relationships with others statistically. As a result, Cable TV will be the most competitive medium in the future. IPTV will be stuck in the middle and can rapidly substitute for existing broadcasting services. While IPTV will severely threaten the satellite broadcasting company which has a relatively small number of subscribers, cable TV will be in a superior position to IPTV.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.171-179
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• 2012

Cooling of hot sections, especially the turbine nozzle and rotor blades, has a significant impact on gas turbine performance. In this study, the influence of precooling of the cooling air on the performance of gas turbines and their combined cycle plants was investigated. A state-of-the-art F-class gas turbine was selected, and its design performance was deliberately simulated using detailed component models including turbine blade cooling. Off-design analysis was used to simulate changes in the operating conditions and performance of the gas turbines due to precooling of the cooling air. Thermodynamic and aerodynamic models were used to simulate the performance of the cooled nozzle and rotor blade. In the combined cycle plant, the heat rejected from the cooling air was recovered at the bottoming steam cycle to optimize the overall plant performance. With a 200K decrease of all cooling air stream, an almost 1.78% power upgrade due to increase in main gas flow and a 0.70 percent point efficiency decrease due to the fuel flow increase to maintain design turbine inlet temperature were predicted.

• Korean Journal of Environment and Ecology
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• v.27 no.1
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• pp.30-51
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• 2013

This study was conducted to identify the impact of river improvement efforts by studying terrestrial insects inhabiting at streamside locations at the Daejeon and Yudeung streams. Seven surveys were conducted from April to October on 2008 and the results were analyzed. Totally 428 species of 110 families belonging to 11 orders of insects were investigated during the course of the present study. The insects identified at the Daejeon stream belonged to 335 species, 99 families and 11 orders, while those at the Yudeung stream were of 350 species, with 98 families and 11 orders. At the Daejeon stream, D-1 and D-2 points were the sites where the most species(178 species) were identified, while at the Yudeung stream, the Y-1 point was the site where the most species(179 species) emerged. In a cluster analysis based on a similarity index, Group A(without river improvement works) and Group B(downtown passing area with river improvement works) were created. Within Group A, survey points were classified as the Daejeon stream group(the A-1 Group) and the Yudeung stream group(the A-2 Group). It was found that the emergence patterns of insects were related to regional characteristics of the streams.

• Child Health Nursing Research
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• v.21 no.1
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• pp.37-45
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• 2015

Purpose: In this study, a comparison was done of the extent of health-related quality of life (HRQoL) for preterm and fullterm children during early childhood, and factors affecting HRQoL in the early childhood of premature children were analyzed. Methods: Eighty mothers of children born prematurely and 83 mothers of children born at fullterm listed on two Internet cafes were sampled for this study. The major instrument used for the study was the TNO-AZL Preschool Quality Of Life (TAPQOL) questionnaire. Results: Total score for HRQoL in the premature group was 80.5 (${\pm}9.9$) and for the full term group, 85.0 (${\pm}8.3$), on a 100-point scale. A comparison of the premature group and full term group showed that the domains which scored relatively lower with respect to HRQoL included the stomach, motor function, anxiety, liveliness and communication. Among the factors that have an impact on HRQoL were 'length of stay in neonatal intensive care unit (${\geq}7$ days)' and 'birth weight (<1,000 gm)'. The explanation power of the model was 17%, which was statistically significant. Conclusion: These findings indicate that a differentiated premature infant follow-up program for children who are hospitalized over 7 days in NICU or weighed under 1,000g at birth is urgently needed.

• Journal of Service Research and Studies
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• v.7 no.2
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• pp.17-41
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• 2017

The purpose of this research is to investigate the factors that impact customer satisfaction and loyalty in mobile payment services. Specifically, this research (1) studies the influence of company reputation on customer satisfaction and loyalty, (2) examines service quality dimensions that increase customer satisfaction, and (3) assesses switching barriers as moderators in influencing customer loyalty. Findings of this empirical research reconfirm the point of view that company reputation, service quality, and switching barriers are crucial for customer satisfaction in mobile payment services. The research methodologies that were used to verify the hypothesis in this study included customized surveys and structural equation modeling. The results demonstrated that company reputation significantly affects customer satisfaction and loyalty. Additionally, the results indicated that only two of the five total service qualities, ease of use and the security/privacy qualities, have positive influences on customer satisfaction. Customer satisfaction has also proven to be a significant influence on loyalty. Lastly, the results showed that among the factors of switching barriers, the factors of lost performance costs, sunk costs, setup costs, the attractiveness of alternatives, and service recovery have moderating effects on the relationships between customer satisfaction and loyalty. Base on the results, this research recommends that firms aim at devising integrated strategies that make switching barriers act as complements to customer satisfaction.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.1-16
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• 2022

The location of the bus stop on urban roads should be installed at a point where it is convenient for users and the impact of bus stops on the traffic flow is minimized. However, the location of the bus stops is determined indiscriminately due to the lack of related research. Therefore, this study developed a traffic accident prediction model and calculated the proper separation distance for the bus stops through an optimization technique. The result of the study indicates that the bus stop can be installed in the form of a mid-block approximately 87 to 166 m away from the intersection in the road section. This result is valid if the number of main road lanes in the road section is 2 to 4 with a level of traffic from 1,000 to 3,000 v/h. In the section with 5 to 6 lanes, it is desirable to install a bus stop close to the intersection by about 42 to 97 m.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.28-41
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• 2022

A road system with CV(Connected Vehicle)s, which is often referred to as a cooperative intelligent transportation system (C-ITS), provides various road information to drivers using an in-vehicle warning system. Road environments with CVs induce drivers to reduce their speed or change lanes to avoid potential risks downstream. Such avoidance maneuvers can be considered to improve driving behaviors from a traffic safety point of view. Thus, empirically evaluating how a given in-vehicle warning information affects driving behaviors, and monitoring of the correlation between them are essential tasks for traffic operators. To quantitatively evaluate the effect of in-vehicle warning information, this study develops a method to calculate compliance rate of drivers where two groups of speed profile before and after road information is provided are compared. In addition, conventional indexes (e.g., jerk and acceleration noise) to measure comfort of passengers are examined. Empirical tests are conducted by using PVD (Probe Vehicle Data) and DTG (Digital Tacho Graph) data to verify the individual effects of warning information based on C-ITS constructed in Seoul metropolitan area in South Korea. The results in this study shows that drivers tend to decelerate their speed as a response to the in-vehicle warning information. Meanwhile, the in-vehicle warning information helps drivers to improve the safety and comport of passengers.

• Journal of Internet Computing and Services
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• v.24 no.1
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• pp.71-86
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• 2023

The purpose of this exploratory study is to compare the differences in public perceptual characteristics of Korean and Chinese societies regarding the metaverse using big data analysis. Due to the environmental impact of the COVID-19 pandemic, technological progress, and the expansion of new consumer bases such as generation Z and Alpha, the world's interest in the metaverse is drawing attention, and related academic studies have been also in full swing from 2021. In particular, Korea and China have emerged as major leading countries in the metaverse industry. It is a timely research question to discover the difference in social awareness using big data accumulated in both countries at a time when the amount of mentions on the metaverse has skyrocketed. The analysis technique identifies the importance of key words by analyzing word frequency, N-gram, and TF-IDF of clean data through text mining analysis, and analyzes the density and centrality of semantic networks to determine the strength of connection between words and their semantic relevance. Python 3.9 Anaconda data science platform 3 and Textom 6 versions were used, and UCINET 6.759 analysis and visualization were performed for semantic network analysis and structural CONCOR analysis. As a result, four blocks, each of which are similar word groups, were driven. These blocks represent different perspectives that reflect the types of social perceptions of the metaverse in both countries. Studies on the metaverse are increasing, but studies on comparative research approaches between countries from a cross-cultural aspect have not yet been conducted. At this point, as a preceding study, this study will be able to provide theoretical grounds and meaningful insights to future studies.