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        검색결과 1,387

        61.
        2023.05 구독 인증기관·개인회원 무료
        The configuration management system was implemented on the basis of a document management system that secured stable understanding, scalability, document security, and convenience in small modular reactor. To reduce the cost and risk of errors, configuration management is implemented to maintain a balance between design requirements, physical configuration, facility configuration information. In the initial stages, configuration change review procedures was developed with the main purpose of change management such as classification system management, configuration control committee management, configuration change review preparation, configuration control committee operation, followup measures, current status and tracking management. The preparation of the configuration change review consisted of preparation, distribution approval, designation of reviewers, review, collection of review opinions, and preparation of resolution results. In the operation of the configuration control committee, it was conducted by designating review members, reviewing members, collecting operation, and approval them. The next step is to supplement and develop the requirements of IEEE Std 828-2012, such as configuration management planning, configuration management control, configuration identification, configuration change control, configuration status monitoring, configuration audit, interface management, and release management. Through this, issue raising, action management, and baseline management will be implemented.
        62.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In wastewater treatment, an emulsion polymer automatic dissolving system is used to mix and dissolve the polymer used as a polymer coagulant with water before it is put into the dissolution tank. In this study, a disperser is developed to mix water and emulsion polymer better in the dissolving system. For this purpose, the flow analysis of the three disperser models was performed to select the disperser for the emulsion polymer automatic dissolving system with the best performance. The excellence of mixing was evaluated by grasping the flow uniformity and the vorticit in the disperser, and it was confirmed that the TYPE3 disperser was excellent.
        4,000원
        70.
        2023.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a precision automatic irrigation system in a nursery by considering the problems and improvements of manual and the conventional automatic irrigation system. The amount of irrigated water between the conventional automatic irrigation system and manual irrigation was 28.7 ± 4.4 g and 14.2 ± 4.3 g, respectively, and the coefficient of variation was less than 30%. However, the coefficient of variation of the conventional automatic irrigation system of 15%, was higher than that of manual irrigation of 30%. The irrigation test using the developed uniform irrigation system attached with the nozzle of a spray angle 80° and most highest uniformity was at height 600 mm. And coefficient of variation of the irrigation uniformity at the center part was within 20%, but irrigation amount of the edge part was lower 50% and over compared to the center part. As a result of a tomato grafting seedling cultivation test using the developed uniform irrigation system, the average plant height of seedling at the edge part was 28 mm but plant height at the center part was higher as 72 mm. Therefore, it was necessary to apply additional irrigation device at the edge part. The irrigation uniformity of the edge concentrated irrigation system was investigated that the irrigation amount of the edge part was irrigated by more than 50% compared with the center part, and coefficient of variation of the irrigation amount at the center part was less than 30%. As a result of a cucumber grafting seedling cultivation test using the edge concentrated irrigation system, the plant height of seedlings in the edge and central part of cultivation bed were 24% and 26%, respectively, so irrigation uniformity was higher then the uniform irrigation system. In order to improve the uniformity of seedlings, it is necessary to adjust the height of boom according to the growth of the seedling by installing a distance sensor in the overhead watering and boom irrigation system.
        4,000원
        71.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In South Korea, the history of the qualifications has been matured with industry development. Since National Technical Qualifications Act was enacted in 1973, the government makes an effort to develop the ability for improving socioeconomic status and the contribution of qualifications to industry. As the industry has been diversified and globalized, the government has efficiently and systematically operating the qualification by enacting Framework Act on Qualifications in 1997. And then, the qualifications are classified into national qualifications, private qualifications, and foreign qualifications. However, it is hard for national qualifications to abolish or establish a qualification by each organization and the privileged license acquisitors as the qualifications are separately operated by the laws and the organizations and lack consistency. For private qualifications, it is harder to organize even by the government because of the entry barriers by each qualification association. For those reasons, it is necessary to organize the system adapted in the changing job market and operated by the organization managing the qualification system with consistency. This research indicates the inefficiency of the qualification system because the work-study parallelism National qualification system, enacted in 2020, is like the qualification system in business in terms of the general operating system and the operator, except the institute and the law related. Therefore, we analyze the work-study parallelism National qualification system and the qualification system in business and suggest the efficient method to operate and the future research plan regarding the whole qualification system.
        5,100원
        72.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, fire accidents in tunnels are sufficiently preventable, but the damage is very large. Therefore, the number of highway traffic accidents is high in spring when spring fatigue occurs and the traffic volume for maple travel increases. In particular, when analyzing the cause of death of people killed in fire accidents in tunnels, it is analyzed that most of them are suffocated by smoke. Therefore, in this study, it can be said that it is meaningful to make a social contribution to reduce the number of traffic accident deaths by establishing an efficient fire suppression system for fire accidents in tunnels.
        4,000원
        73.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focused on diagnosing and analyzing the level of sustainable development for each fishing communities by applying the sustainable development index in the fishing communities to support the policy of revitalizing the fishing communities. In terms of methodology, diagnostic indicators for rural areas were used through previous studies and literature surveys, and three categories, five fields and 27 indicators were finally selected through collecting opinions from experts. After deriving the weight for each indicator in detail, the final sustainable development index of the fishing communities was applied to fishing village fraternity. Based on the results of the analysis of the application of sustainable development cases in fishing communities, policy support should be implemented differentially according to regional decline factors and potential growth factors. In the population and social sector, it is necessary to consider ways to reduce population and reduce aging. In the industrial and economic sectors, fishing activation and systematic support for fishing-related industries should be provided. In the marine and built environment sector, the government's active project execution and budget support are required. In addition, it is expected to be used in various ways in the process of developing fishing communities and establishing revitalization plans that reflect the characteristics of the region.
        6,000원
        74.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In existing ceramic mold manufacturing processes, inorganic binder systems (Si-Na, two-component system) are applied to ensure the effective firing strength of the ceramic mold and core. These inorganic binder systems makes it possible to manufacture a ceramic mold and core with high dimensional stability and effective strength. However, as in general sand casting processes, when molten metal is injected at room temperature, there is a limit to the production of thin or complex castings due to reduced fluidity caused by the rapid cooling of the molten metal. In addition, because sodium silicate generated through the vitrification reaction of the inorganic binder is converted into a liquid phase at a temperature of 1,000 °C. or higher, it is somewhat difficult to manufacture parts through high-temperature casting. Therefore, in this study, a high-strength ceramic mold and core test piece with effective strength at high temperature was produced by applying a Si-Na-Ti three-component inorganic binder. The starting particles were coated with binary and ternary inorganic binders and mixed with an organic binder to prepare a molded body, and then heat-treated at 1,000/1,350/1,500 °C to prepare a fired body. In the sample where the two-component inorganic binder was applied, the glass was liquefied at a temperature of 1,000 °C or higher, and the strength decreased. However, the firing strength of the ceramic mold sample containing the three-component inorganic binder was improved, and it was confirmed that it was possible to manufacture a ceramic mold and core via high temperature casting.
        4,000원
        75.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Fine dust significantly affects the atmospheric environment, and various measures have been implement to reduce it. The aim of this study is to reduce fine dust on roads by implementing porous pavements and a clean road system using the low-impact development technique. METHODS : We conducted quality tests (draindown, cantabro loss rate, tensile strength ratio, dynamic stability, and indoor permeability coefficient tests) and performance evaluation (dynamic modulus and Hamburg wheel-tracking tests) on the porous asphalt mixture. Subsequently, we constructed a porous pavement road in a test bed and conducted a permeability test. In the test bed, we installed a nozzle, a water tank, and a fluid pump to water the roadside. After the clean road system was completely installed, we measured the concentration of fine dust before and after water was sprayed. Additionally, we conducted a total suspended solids (TSS) test to confirm the reduction in re-suspended dust. RESULTS : All results from the quality test of the porous asphalt mixture satisfy the standards stipulated by the Ministry of Land, Infrastructure and Transport. Results from the dynamic modulus test show a low plastic deformation resistance but a high fatigue crack resistance. The results from the Hamburg wheel-tracking test satisfy the U.S. Department of Transportation standards. After the porous pavement was constructed, a permeability test was conducted, and the result satisfies the standard value. Using a particle counter, we measured the concentration of fine dust before and after water spraying, and results show 12.08% and 10.23% for PM10 and PM2.5 particles, respectively. The results from the TSS test show that after the initial water spray, almost all re-suspended dust are removed from a road. In unfavorable road conditions, almost all re-suspended dust are removed after a second water spray. CONCLUSIONS : The results of all of quality tests performed on a porous asphalt mixture satisfy the standards. By applying the results to a test bed, the problem of securing water is solved. Using the clean road system, 12.08% and 10.23% of PM10 and PM2.5 particles are removed, respectively. The system removes PM10 particles (larger particles) more effectively compared with PM2.5 particles. IN the future, we plan to revise the maintenance plan such that the porous pavement can exhibit long-term performance. Because pipe freezing may occur in the winter, we plan to analyze the periodic maintenance plan of the porous pavement and develop a solution to mitigate the issue of freezing pipes in the winter.
        4,300원
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