• Journal of Korea Port Economic Association
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• v.39 no.2
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• pp.111-128
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• 2023

Due to the coronavirus pandemic, interest in outdoor leisure activities is growing. Among outdoor leisure activities, marine sports can be seen as having good conditions to enjoy in Korea. In the case of yachting among marine sports, a number of yacht experience programs have recently been operated centered on Gwanganli and Suyeong Bay in Busan. This yacht experience is an attractive tourism product that can be enjoyed casually, and can bring stress relief to many users. This study tried to verify the effect of the attractiveness of the yacht experience on the stress recovery based on the tourists' experiences using the yacht experience tour. In addition, we tried to verify the intention of revisiting the yacht experience or sharing it with others through SNS through this stress recovery. In addition, as a moderator variable, the difference between the MZ generation and other generations, which use SNS more actively than other generations, was presented and its significance was verified. The survey of this study was conducted online for tourists who experienced yacht experience in Busan. As a result of the analysis, among the attractive factors of the yacht experience, the program, landscape, facilities and service was found to have a significant influence on the users' stress recovery, and satisfaction through stress recovery had a significant effect on the intention to revisit and to share the SNS. In the verification of the moderating effect according to age, a generational difference in revisit intention between the MZ generation and other generations was confirmed. Through this study, it was suggested that various programs of yacht experience should be developed to induce users to revisit, and various marketing using SNS should be carried out.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3543-3548
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• 2023

Shutdown chemistry evolution is performed in nuclear power plants at each refueling outage (RFO) to establish safe conditions to open system and minimize inventory of corrosion products in the reactor coolant system (RCS). After hydrogen peroxide is added to RCS during shutdown chemistry evolution, corrosion products are released and are removed by filters and ion exchange resins in the chemical volume control system (CVCS). Shutdown chemistry evolution including RCS clean-up time to remove released corrosion products impacts the critical path schedule during RFOs. The estimation of clean-up time prior to RFO can provide more reliable actions for RCS clean-up operations and transients to operators during shutdown chemistry. Electric Power Research Institute (EPRI) shutdown calculator (SDC) enables to provide clean-up time by Co-58 peak activity through operational data from nuclear power plants (NPPs). In this study, we have investigated the results of EPRI SDC by shutdown chemistry data of Co-58 activity using NPP data from previous cycles and modeled the estimated clean-up time by EPRI SDC using average Co-58 activity of the NPP. We selected two RFO data from the NPP to evaluate EPRI SDC results using the purification time to reach to 1.3 mCi/cc of Co-58 after hydrogen peroxide addition. Comparing two RFO data, the similar purification time between actual and computed data by EPRI SDC, 0.92 and 1.74 h respectively, was observed with the deviation of 3.7-7.2%. As the modeling the estimated clean-up time, we calculated average Co-58 peak concentration for normal cycles after cycle 10 and applied two-sigma (2σ, 95.4%) for predicted Co-58 peak concentration as upper and lower values compared to the average data. For the verification of modeling, shutdown chemistry data for RFO 17 was used. Predicted RCS clean-up time with lower and upper values was between 21.05 and 27.58 h, and clean-up time for RFO 17 was 24.75 h, within the predicted time band. Therefore, our calculated modeling band was validated. This approach can be identified that the advantage of the modeling for clean-up time with SDC is that the primary prediction of shutdown chemistry plans can be performed more reliably during shutdown chemistry. This research can contribute to improving the efficiency and safety of shutdown chemistry evolution in nuclear power plants.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.1-9
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• 2024

This study proposes a multi-scale template matching technique with image pyramids (TMI) to measure structural dynamic displacement using a vision sensor under atmospheric turbulence conditions and evaluates its displacement measurement performance. To evaluate displacement measurement performance according to distance, the three-story shear structure was designed, and an FHD camera was prepared to measure structural response. The initial measurement distance was set at 10m, and increased with an increment of 10m up to 40m. The atmospheric disturbance was generated using a heating plate under indoor illuminance condition, and the image was distorted by the optical turbulence. Through preliminary experiments, the feasibility of displacement measurement of the feature point-based displacement measurement method and the proposed method during atmospheric disturbances were compared and verified, and the verification results showed a low measurement error rate of the proposed method. As a result of evaluating displacement measurement performance in an atmospheric disturbance environment, there was no significant difference in displacement measurement performance for TMI using an artificial target depending on the presence or absence of atmospheric disturbance. However, when natural targets were used, RMSE increased significantly at shooting distances of 20 m or more, showing the operating limitations of the proposed technique. This indicates that the resolution of the natural target decreases as the shooting distance increases, and image distortion due to atmospheric disturbance causes errors in template image estimation, resulting in a high displacement measurement error.

• Science of Emotion and Sensibility
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• v.26 no.4
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• pp.71-92
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• 2023

This study investigates the symbolism and meaning of the bead design, its relationship with the Silla culture, and the conditions of glass bead manufacturing to verify the theory of Silla's production of Silla face-inlaid glass beads with excellent artistry and technology. The research method includes investigating the design analysis, ancient documents, myths, relics, glass, and metal production techniques. Moreover, Hongshan cultural relics and other cases of inlaid glass beads were collected. There are records in the literature that the people of Makhan, Buyeo and Silla of ancient Korea people considered beads as treasures and used them for accessories. It was confirmed that all the design elements of the bead-patterned hair topknot, golden crown, birds, and flower trees were closely related to the myth of Kim Al-ji of Silla, the oviparous tales and the sacred birds and divine beasts of the north. Moreover, the pattern and arrangements were found to be similar in other Silla relics. The origin of beads and face pendants was Hongsan culture, and a stone cast for beads was discovered in Bukpyo of Gojoseon, the lower-level culture of Hajiajeom. In addition, excavating inlaid glass beads from Sik-ri tombs of Korea and a face-inlaid glass bead from Toganmori tombs in Japan confirms the theory of Silla's production. The fact that the Baekje people of ancient Korea had a glass bead manufacturing office in Japan in the fifth centuries suggests that the Silla people also had a manufacturing plant in Java, Indonesia, because this place was a crossroads of Silla's Sea Silk Road and a source of raw materials and labors with a close relationship to Silla. Therefore, the face-inlaid glass bead was indeed self-made by Silla, who possessed the tradition of bead myths and hair topknot, and the high-level skills such as gold crowns and metal inlays.

• Journal of Korean Society of Disaster and Security
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• v.17 no.1
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• pp.1-8
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• 2024

In Korea, mountainous areas cover 60% of the land, leading to increased factors such as concentrated heavy rainfall and typhoons, which can result in debris flow and landslide. Despite the high risk of disasters like landslides and debris flow, there has been a tendency in most regions to focus more on post-damage recovery rather than preventing damage. Therefore, in this study, precise topographic data was constructed by conducting on-site surveys and drone measurements in areas where debris flow actually occurred, to analyze the risk zones for such events. The numerical analysis program RAMMS model was utilized to perform debris flow analysis on the areas prone to debris flow, and the actual distribution of debris flow was compared and analyzed to evaluate the applicability of the model. As a result, the debris flow generation area calculated by the RAMMS model was found to be 18% larger than the actual area, and the travel distance was estimated to be 10% smaller. However, the simulated shape of debris flow generation and the path of movement calculated by the model closely resembled the actual data. In the future, we aim to conduct additional research, including model verification suitable for domestic conditions and the selection of areas for damage prediction through debris flow analysis in unmeasured watersheds.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.6
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• pp.569-582
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• 2023

In recent years, the service life of major SOC facilities in south korea has exceeded 30 years, and rapid aging is expected within the next 10 years. This has led to a growing recognition of the need for proactive maintenance of these facilities. Consequently, there have been numerous research efforts to introduce smart inspection technologies into maintenance. However, the current system relies primarily on manpower for safety inspections and diagnostics, and on-site surveys rely on visual inspections. Manpower inspections can be time-consuming, and subjective errors may occur during result analysis. In the case of tunnels, there are disadvantages, such as the loss of social overhead capital due to partial closures during inspections. Therefore, institutionalizing smart safety inspections is essential, considering specific measures like using advanced equipment and updating qualifications for experts. Furthermore, it is necessary to verify and validate safety inspection results using advanced equipment before instituting changes. This could be achieved through national-level official research programs and the operation of verification and validation institutions. If smart inspection technology is introduced into maintenance, routine inspections of SOC facilities, such as tunnels, will become feasible. As a result, maintenance technology capable of early detection and proactive response to safety incidents caused by changes in facility conditions is anticipated.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.345-357
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• 2023

Nuclear forensics has been understood as a mendatory component in the international society for nuclear material control and non-proliferation verification. Radiochronometry of nuclear activities for nuclear forensics are decay series characteristics of nuclear materials and the Bateman equation to estimate when nuclear materials were purified and produced. Radiochronometry values have uncertainty of measurement due to the uncertainty factors in the estimation process. These uncertainties should be calculated using appropriate evaluation methods that are representative of the accuracy and reliability. The IAEA, US, and EU have been researched on radiochronometry and uncertainty of measurement, although the uncertainty calculation method using the Bateman equation is limited by the underestimation of the decay constant and the impossibility of estimating the age of more than one generation, so it is necessary to conduct uncertainty calculation research using computer simulation such as Monte Carlo method. This highlights the need for research using computational simulations, such as the Monte Carlo method, to overcome these limitations. In this study, we have analyzed mathematical models and the LHS (Latin Hypercube Sampling) methods to enhance the reliability of radiochronometry which is to develop an uncertainty algorithm for nuclear material radiochronometry using Bateman Equation. We analyzed the LHS method, which can obtain effective statistical results with a small number of samples, and applied it to algorithms that are Monte Carlo methods for uncertainty calculation by computer simulation. This was implemented through the MATLAB computational software. The uncertainty calculation model using mathematical models demonstrated characteristics based on the relationship between sensitivity coefficients and radiative equilibrium. Computational simulation random sampling showed characteristics dependent on random sampling methods, sampling iteration counts, and the probability distribution of uncertainty factors. For validation, we compared models from various international organizations, mathematical models, and the Monte Carlo method. The developed algorithm was found to perform calculations at an equivalent level of accuracy compared to overseas institutions and mathematical model-based methods. To enhance usability, future research and comparisons·validations need to incorporate more complex decay chains and non-homogeneous conditions. The results of this study can serve as foundational technology in the nuclear forensics field, providing tools for the identification of signature nuclides and aiding in the research, development, comparison, and validation of related technologies.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.45-52
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• 2024

Estimating the sales price of a residential building development project is difficult because of it has many complex variables such as location, environment, and economic conditions. Many previous studies related to influence factors of the sales price is to identify by survey of experts and it is few studies by comparing with actual sales price. Accordingly, the purpose of this study is to identify the factors influenced on the projects by using correlation analysis from collected actual data in this study. For the purpose, first, the factors such as economy, location, housing, financial environmental factors were identified from previous studies. Second, data were collected on actual sale prices and selected factors. Finally, the actual sales price and factors were compared and analyzed by using correlation analysis. As a result, the R² values of economy, location, housing and financial environmental factors were over 0.5 respectively. Therefore, it was confirmed that these factors were significantly correlated with actual sales price. The results of this study are expected to be utilized as basic data for research and development of a new sale prices prediction model.

• Russian Language and Literature
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• no.63
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• pp.233-257
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• 2018

This study aims to analyze the migrants who returned to Russia from the CIS during the time of the Soviet Union, and it especially aims to analyze the migrants' survival and the labor policies directly related to them. However, this analysis is not a utility analysis that analyzes the economic value and the economic advantages and disadvantages of the policy. Russia is no entering into a new multicultural era whether they want it or not. This study aims to examine the fundamental identity (正體性) and direction (方向性) of the migrant labor policy Russia had during the Soviet Union times during this flow in the eras. If so, what is the identity of the migrant worker policy of Russia? By looking through the time and the environment it was created, the Russian migrant policy can be a good medium for understanding the Russian race, human rights, and other people's views, rather than just one economic and social policy. Therefore, this study strived to use the analysis of the characteristics of the policy as the basic propel strategy. Representative migrant workers' policies during the Soviet period include residence registration system, work permit system and quota system for migrant workers. The three representative policies of migrant workers were selected as the basic analysis policy of this study, and the characteristics and direction of the whole policy were analyzed by analyzing the similarities and differences of each policy. Also, even though on the surface these policies were carried out by using the same consumers (Migrant workers who returned from CIS) as the subject, practically, the subjects were racially divided into Slavic and non-Slavic. Thus, this study viewed in the perspective of looking at how each policy was applied to both the Slavic and the non-Slavic. Regardless of the conditions, environments, and the racial divisions of the policy consumers, there was an undeniable common point that from the past to the present, 'migrant workers' were always the weak and were always the stranger. During the processes of drafting and carrying out each policy, depending on the political and economic environments, the policies were applied either with benefits or disadvantages to the migrant workers. In addition, the policy was implemented differently according to the Slavic and to the non-Slavic. However, it was just an advantage and disadvantage in the presence of discrimination; it was not a change in the fundamental view of the other. Therefore, when analyzing the Russian migrant workers' policy in the Soviet era, we can observe the tendency toward the weak and the strangers in Russia and clearly understand the hidden intentions. By understanding identity and direction, we can understand the current Russian multicultural policies and further predict the future Russian multicultural policy.

• Journal of IKEEE
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• v.28 no.3
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• pp.310-320
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• 2024

This article describes the 5G-NR-V2X system and its communication performance methodology. We present a system that can develop and verify the performance of self-driving services in a real road test environment using OBU and RSU for 5G-NR-V2X communication (level 4 or higher). This system ensures ultra-high speed (150Mbps or more), ultra-low latency (3ms or less), and high reliability (99.99 percent) in communication robustness, even under malicious conditions. The 5G-NR-V2X system and performance analysis method proposed in this paper are anticipated to aid in the development of V2X communication technologies that are ultrafast, ultralow-delay, and high-confidence. In addition, it is expected that the services validated by the suggested performance analysis technique will enhance technological competitiveness in the road, transportation, logistics, and commerce industries.