• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.159-179
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• 2022

Often a network becomes complex, and multiple entities would get in charge of managing part of the whole network. An example is a utility grid. While the entire grid would go under a single utility company's responsibility, the network is often split into multiple subsections. Subsequently, each subsection would be given as the responsibility area to the corresponding sub-organization in the utility company. The issue of how to make subsystems of adequate size and minimum number of interconnections between subsystems becomes more critical, especially in real-time simulations. Because the computation capability limit of a single computation unit, regardless of whether it is a high-speed conventional CPU core or an FPGA computational engine, it comes with a maximum limit that can be completed within a given amount of execution time. The issue becomes worsened in real time simulation, in which the computation needs to be in precise synchronization with the real-world clock. When the subject of the computation allows for a longer execution time, i.e., a larger time step size, a larger portion of the network can be put on a computation unit. This translates into a larger margin of the difference between the worst and the best. In other words, even though the worst (or the largest) computational burden is orders of magnitude larger than the best (or the smallest) computational burden, all the necessary computation can still be completed within the given amount of time. However, the requirement of real-time makes the margin much smaller. In other words, the difference between the worst and the best should be as small as possible in order to ensure the even distribution of the computational load. Besides, data exchange/communication is essential in parallel computation, affecting the overall performance. However, the exchange of data takes time. Therefore, the corresponding consideration needs to be with the computational load distribution among multiple calculation units. If it turns out in a satisfactory way, such distribution will raise the possibility of completing the necessary computation in a given amount of time, which might come down in the level of microsecond order. This paper presents an effective way to split a given electrical network, according to multiple criteria, for the purpose of distributing the entire computational load into a set of even (or close to even) sized computational loads. Based on the proposed system splitting method, heavy computation burdens of large-scale electrical networks can be distributed to multiple calculation units, such as an RTDS real time simulator, achieving either more efficient usage of the calculation units, a reduction of the necessary size of the simulation time step, or both.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.562-569
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• 2022

The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

• The Korea Journal of Herbology
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• v.32 no.4
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• pp.25-32
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• 2017

Objectives : Chungsimyeonja-eum (CSYJE; Qingxinlianzi-yin in Chinese; Seishinrenshi-in in Japanese), a traditional herbal medicine, has been used for treating mouth dryness, hyperuresis. This study was designed to determine preservation period of CSYJE. We investigated the stability and biological activity of CSYJE depending on the preservation temperature and periods. Methods : CSYJE decoction was preserved for 0-6 or 12 months at room temperature (RT, $23{\pm}1^{\circ}C$) or refrigeration ($4^{\circ}C$). To evaluate the stability of CSYJE decoction, pH and dissolved solids content were measured. High-performance liquid chromatography (HPLC) analysis was performed to determine marker compounds-liquiritin apioside, liquiritin, baicalin, wogonoside, and glycyrrhizin-in CSYJE. To determine anti-inflammatory effect of CSYJE, prostaglandin $E_2$ ($PGE_2$) was measured in LPS-stimulated RAW 264.7 macrophages. Results : Both at RT and $4^{\circ}C$, pH was decreased depending on the preservation periods. There was no changes in dissolved solids content depending on the preservation temperature and periods. Both at RT and $4^{\circ}C$, the contents of liquiritin apioside and liquiritin were slightly increased at 1 month of storage. The level of baicalin was decreased time-dependently and the disappearance rate at RT is larger than at $4^{\circ}C$. CSYJE inhibited $PGE_2$ production in LPS-stimulated RAW 264.7 cells and maintained inhibitory effect by 12 months both at RT and $4^{\circ}C$. Conclusions : Based on the disappearance rate of the baicalin in CSYJE, the preservation period is recommended within 8 months for RT and 12 months for $4^{\circ}C$.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.403-421
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• 2021

Most of the urban tunnels in Korea, which are represented by the 1st to 3rd subways, use the drainage tunnel by NATM. Recently, when a construction project that actively utilizes large-scale urban space is promoted, negative effects that do not conform to the existing empirical rules of urban tunnels may occur. In particular, there is a high possibility that groundwater fluctuations and hydrodynamic behavior will occur owing to the practice of tunnel technology in Korea, which has mainly applied the drainage tunnel. In order to solve the problem of the drainage tunnel, attempts are being made to control groundwater fluctuations. For this, the establishment of tunnel groundwater management standard concept and the analysis of the tunnel hydraulic behavior were performed. To prevent the problem of groundwater fluctuations caused by the construction of large-scale tunnels in urban areas, it was suggested that the conceptual transformation of the empirical technical practice, which is applied only in the underground safety impact assessment stage, to the direction of controlling the inflow in the tunnel, is required. And the relationship between the groundwater level and the inflow of the tunnel required for setting the allowable inflow when planning the tunnel was derived. The introduction of a tunnel groundwater management concept is expected to help solve problems such as groundwater fluctuations, ground settlement, depletion of groundwater resources, and decline of maintenance performance in various urban deep tunnel construction projects to be promoted in the future.

• Journal of Science Education
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• v.46 no.1
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• pp.53-65
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• 2022

In the application and composition of learning content, the field trip learning of scientific inquiry could provide a positive effect. Also, it can arouse an experience of various inquiry activities through open thinking. In addition, it could take a positive effect by providing the diversity and specificity of wildlife experience for the living organism. The biology inquiry program of the field trip is a necessary process to acquire ecological experiences in the learning context. However, there is some problem to solve before the performance of field trip learning as professional knowledge of the outdoors inquiry. Therefore, this study developed a field trip inquiry program for the plant in a coastal dune using artificial intelligence to assist professional knowledge. The researcher carried out literature reviews and analysis related to studies and programs to investigate learning steps, content, and strategy. Also, this study investigated the effects of the program on the affective domain of gifted elementary science students. According to the results of this study, the program can provide a positive effect on motivation, task commitment, and attitude level. Consequently, the field trip learning program for plant in the coastal dune using artificial intelligence developed in this study can arouse a positive effect on the affective domain. Therefore, additional study is necessary related to inquiry programs of the field trip for various students and sites.

• Journal of Korea Entertainment Industry Association
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• v.15 no.7
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• pp.17-32
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• 2021

This is an environmental analysis study for discovering specialized local sports tourism and aims to provide implications for the development of sports tourism industry in the Chuncheon region by analyzing the current status of domestic and overseas sports tourism and presenting overseas cases of specialized regional sports tourism. Therefore, through SWOT analysis and secondary data survey, implications for the development direction according to facilities, programs, and public relations and marketing were derived. Sports tourism contributes to vitalization of local economy by converging with local tourism centering on sports participation or viewing. Thus, it must be organized with differentiated products taking into account the characteristics of the area. An investigation of the main components of domestic and overseas sports tourism shows that mega sports events or specialized local leisure sports are connected to tourism resources for commercialization. In Korea, 3 to 4 local areas are discovered and supported annually through the specialized local sports tourism promotion program. This study suggests a development plan by evaluating and analyzing the performance of the Chuncheon Spo-Tour program. In terms of facility, it is necessary to construct accommodation facilities that harmonize with the natural environment, develop new programs connected to Songam Sports Town, and reinforce existing equipment. In terms of program, it is necessary to develop canoe/kayak water courses utilizing Uiam-Lake, train professionals to operate programs, and develop programs that take into consideration seasonal characteristics as well as the level of each participants. In terms of PR/marketing, it is important to build competitiveness by using ICT, improving public awareness of the sites, and adopting reasonable pricing policies. The development of specialized local sports tourism products through remedies and efforts will contribute to vitalization of local economy.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.269-278
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• 2021

This study was conducted to develop a learning competency scales customized for learning programs conducted by Center for Teaching & Learning at A University. To achieve this purpose, a preliminary study was set up, which consists of three competency groups (basic competency, intensity competency, application competency) and 13 learning competency factors through a review of previous studies. In order to verify the reliability and validity of the provisional learning competency scales, an online survey was conducted on A university students in September 2020, The collected questionnaire data were organized and exploratory factor analysis and confirmatory factor analysis were conducted. As a result of exploratory factor analysis, 13 learning competency was reduced to 10 as the three competency groups were maintained. As a result of the confirmatory factor analysis, the model was found to be good, Also, as a result of analyzing the reliability of the confirmed learning competency factors, all 10 factors showed a good level of .7 or more. The learning competency scales developed through this study can be used as basic data for performance evaluation and development of new programs of CTL learning program.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.427-436
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• 2020

This study aims to understand human rights sensibility in university varsity teams and to compare and analyze differences in human rights sensibility by variables related to university varsity teams. In order to achieve the purpose of this study, 188 student-athletes from 10 universities were selected. The collected data were analyzed in descriptive analysis, reliability analysis, one-way ANOVA, Scheffe using IBM SPSS 24.0. First, based on the episodes, the episodes with the highest human rights sensitivity are the right to labor of migrant workers and happiness rights, and the episodes with the lowest human rights sensitivity are the right to freedom of detention and privacy rights. In addition, among the sub-factors of human rights sensitivity, perception of responsibility and perception of behavior are higher than perception of outcome. Second, there are differences in the human rights sensitivity of the university varsity team depending on the size and the level of performance of the university varsity team. Third, there are differences in the human rights sensibility of the university varsity team depending on the educational characteristics (volunteer activity and human rights education) of the university varsity team.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.139-147
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• 2022

In this study, we designed a high-strength, low-alkali type cement composite for artificial reef by mixing various binders and evaluated whether it is possible to manufacture it with an ME method 3D printer. As a result of the tests, it is found that it is important to control the water-binder ratio, the silica sand-binder ratio, and the type of silica sand in order to control the fluidity of the cement composites to enable 3D printing. The surface quality of 3D printer output can be achieved by adjusting the amount of viscosity agent added while obtaining printable fluidity. In the cement composites mixing proportion using the alpha-type hemihydrate gypsum, a setting control agent needs to be used to control the quick setting effect. It is also necessary to derive the time to maintain the fluidity, and to apply it when printing. To obtain the required strength, the mix proportion needs to be modified while satisfying the fluidity level of 3D-printable cement composites. In the present study, 3D-printable mix proportions were designed by the use of multi-component binders including alpha-type hemihydrate gypsum a for low-alkali type artificial reefs, and the printability was confirmed. A further study needs to be performed to quantitatively evaluate the alkali reduction effect.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.69-80
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• 2022

The proportion of buildings over 30 years old in Korea has increased, from 29.0% in 2005 to 37.8% in 2019. These old buildings were built during a time in which there was a lack of building-related safety standards in areas such as fire safety performance. Worse, during their years of use, many such old buildings have had illegal changes and extensions made, making them more vulnerable in terms of safety. Fire safety investigations are being conducted to prevent large-scale disasters in multi-use buildings, but no investigation has been conducted at the regional district level, where small-scale old buildings are concentrated. Therefore, to identify fire risk factors in the old building district where old buildings are concentrated, the composition characteristics of the buildings were first analyzed. To examine the spatial characteristics of old building districts in order to derive fire risk factors, the results of this analysis based on the structure, use, roof type, and year of approval for use are as follows. It was found through our analysis that as of the date of approval for the use of the building, the main structure of the building has the greatest impact.