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        검색결과 1,269

        81.
        2022.10 구독 인증기관·개인회원 무료
        Organic waste generated by small and medium-sized (S&M-sized) metal decontamination in NPP decommissioning. To lower the concentration of these organic substances for a level acceptable at the disposal site, the project of “Development of Treatment Process of Organic Decontamination Liquid Wastes from Decommissioning of Nuclear Power Plants” is being carried out. The conditioning and treatment process of organic liquid waste was designed. Also, the literature was investigated to make simulated organic liquid waste, and the composition of these waste was analyzed and compared. As the decontamination agent, organic acids such as EDTA, oxalic acid, citric acid are used. The sum of the concentrations of these organic materials was set to a maximum value of 1,000 ppm. The major metal ions of the decontamination liquid waste estimated are 59Fe, 51Cr, 54Mn, 63Ni, and the concentrations are respectively 527, 163, 161, 159 ppm. Additional major metal ions are 60Co, 58Co, 137Cs. 58Co is replaced by 60Co because it has the same chemical properties as 60Co. Unlike the HLW, the contamination level of S&M-sized metal in primary system was quite low, so 60Co is set to 2,000 Bq/g. Considering the contribution of fission and gamma ray dose constant, 137Cs was estimated to 360 Bq/g. Also, suspended solids of decontamination liquid waste were set at 500 ppm. Under these assumptions, the simulated organic liquid waste was made, and then organic substances and metal ions were analyzed with TOC analyzer and ICP-OES. The TOC analysis value was expected to 392 ppm in consideration of the equivalent organic quantity. the test result was 302 ppm. Some of organics appears to have been decomposed by acid. The values of metal ions (Fe3+, Cr3+, Mn2+, Ni2+) analyzed by ICP-OES are 139, 4, 152, 158 ppm, respectively. A large amount of Cr3+ and Fe3+ were expected to exist as ions, but they existed in the form of suspended solid. Mn2+ and Ni2+ came out similar to the expected values. The designed conditioning and treatment process is largely divided into pretreatment, conditioning, and decomposition processes. After collecting in the primary liquid waste storage tank, large particulate impurities and suspensions are removed through a pretreatment process. In the conditioning process, treated liquid waste passes through UF/RO membrane system, and pure water is discharged to the environment after monitoring. Concentrated water is decomposed in the electrochemical catalyst decomposition process, then this water secondarily passes through the RO membrane system and then discharged to the environment after monitoring. Through an additional experiment, the conditioning and treatment process will be verified.
        82.
        2022.10 구독 인증기관·개인회원 무료
        Since SMR’s reduced reactor radius results in higher neutron leakage, SMR operates at a relatively lower discharge burnup level than traditional Light Water Reactors (LWRs). It may result in larger spent fuel amounts for SMRs. Furthermore, recent studies demonstrated that NuScale reactor will generate a significantly higher volume of low- and intermediate-level waste owing to components located near the active core including the core barrel and the neutron reflector. For spent nuclear fuel simulation, FRAPCON-4.0 was updated. Major modifications were made for fission and decay gas release, pellet swelling, cladding creep, axial temperature distribution, corrosion, and extended simulation time covering from steady-state to dry storage. In this study, typical 17×17 PWR fuel (60 MWd/kgU) and NuScale Power Module (36 MWd/kgU) was compared. NuFuel-HTP2™ fuel assembly, which has a half-length of proven LWR fuel, was employed. Owing to the lower discharge burnup and operating temperature, the maximum hydrogen pickup was 73 wppm and the maximum hoop stress was ~25 MPa. Therefore, hydride reorientation issue is irrelevant to SMR spent fuel. In this context, the current regulatory limit for dry storage (i.e. 400°C and 90 MPa) can be significantly alleviated for LWR-based SMRs. The increased safety margin for SMR spent fuel may compensate high spent fuel management cost of SMRs incurred by an increased amount. The comprehensive analysis on SMR spent fuel management implications are discussed based on simulated SMR fuel characteristics.
        84.
        2022.10 구독 인증기관·개인회원 무료
        In addition to Korea, various countries such as the United States, the United Kingdom, France, and China are designing small module-type reactors. In particular, a small modular reactor is the power of 300 MWe or less, in which the main equipment constituting the nuclear reactor is integrated into a single container. Depending on the purpose, small modular reactors are being developed to help daily life such as power, heating supply, and seawater desalination, or for power supply such as icebreakers, nuclear submarines, and spacecraft propellants. Small modular reactors are classified according to form. It can be classified into light-water reactors/ pressurized light-water reactors based on technology proven in commercial reactors, and non-lightwater reactors based on fuel and coolant type such as Sodium-cooled Fast Reactor, High temperature gas-cooled reactor, Very high temperature reactor and Moltenn salt reactor. SMRs, which are designed for various purposes, have the biggest difference from commercial nuclear reactors. The size of SMRs is as small as 1/5 of that of the commercial reactors. Several modules may be installed to generate the same power as commercial reactors. Because of the individually operation for each module, load follow is possible. Also, The reactor can be cooled by natural convection because the size is small enough. It is manufactured as a module, the construction period can be reduced. Depending on the characteristics of these SMRs, application for safeguards is considered. There are many things to consider in terms of safeguards. Therefore, it is IAEA inspection or other approaches for SMRs installed and remotely operated in isolated areas, data integrity for remote monitoring equipment to prevent the diversion of nuclear materials, verification method and material accountancy and control for new fuel types and reactors. Since SMR is more compact and technical intensive, safeguards should be considered at the design stage so that safeguards can be efficiently and effectively implemented, which is called the Safeguards by design (SBD) in the IAEA. In this paper, according to the characteristics of SMR, we will analyze the advantages/disadvantages from the point of view of safeguards and explain what should be considered.
        89.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Enhancing income for small-scale farmers in developing countries, is one of the major concerns for governments and many stakeholders. This is attributed by the fact that, a majority of smallscale farmers in the region are characterized by low income earners caused by agronomic related challenges, such as low productivity of input factors. In addressing this challenge, the purpose of this study was to assess the impact of outgrower scheme on its members’ income, using the propensity score matching approach. Through this approach the study assessed cross-sectional data, collected from small-scale tea farmers in the Mufindi district, founded in Tanzania. Results of the assessment on the impact of outgrower scheme on its members, suggest that the scheme has a negative and insignificant impact on its members’ income. This implies that, the outgrower scheme does not meet its intended objective of raising the income of its members, due to failure of improving quality as well as quantity of tea produced in the study area.
        4,000원
        90.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to suggest a plan to improve the level of acceptance of related technologies and the transition to smart factories of small and medium-sized manufacturing enterprises by using ‘technology readiness’ and ‘integrated technology acceptance model’. To this end, the research hypothesis was verified by collecting questionnaire data from 130 small and medium- sized manufacturing companies in Korea and conducting path analysis. First, optimism affects performance expectations, social influence, and facilitation conditions, innovation affects performance expectations, effort expectations, and social influence, discomfort affects performance expectations, social influence, and facilitation conditions, and anxiety affects effort expectations, social influence and facilitation conditions. has been proven to affect Finally, performance expectations, effort expectations, social influence, and facilitation conditions were verified to have a significant positive effect on the intention to accept technology.
        5,100원
        91.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the method of continuous improvement of small-medium company production processes through POSCO's QSS(Quick Six Sigma) activities. QSS is a field operation technique that encompasses the advantages of Six Sigma, TPS(Toyota Production System), TQM (Total Quality Management), and IE(Industrial Engineering). Through this, POSCO not only encourages activities centered on related small and medium-sized partners, etc., but is also expected to contribute to the continuous improvement of the company's own production process through QSS activities. In this study, rather than unconditionally carrying out activities according to the needs of large companies, the research is to help the continuous improvement of the actual production process of small and medium-sized enterprises by effectively applying and spreading QSS activities in consideration of the characteristics and environment of the company. For this purpose, empirical research is conducted on the process improvement activities and QSS activities of company Y, which has less than 100 assembly and production quality and inspection processes among SMEs. The changes in the production process improvement of SMEs through the application of the final QSS were investigated through empirical studies.
        4,200원
        92.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 중국 강소성 소주 운암사 탑과 서광사 탑, 그리고 절강성 금화 만불탑 안에서 발견된 소형 금동불상의 종류와 상태, 그리고 상들이 탑 내 봉안된 의미를 탐색한 글이다. 오대~북송 초, 즉 10세기 후반~11세기 중엽에 조성된 세 탑 안에서는 탑의 제3층 탑신부 혹은 탑 아래에 조성된 석실에서 각기 6구, 9구, 그리고 60여 구의 금동불이 수습되었다. 이 시기 불탑 안에 소형 불상이 안치되어 있음은 잘 알려진 사실이나 안치된 상의 성격이나 그 의미에 대해서는 심도 있는 논의가 이루어지지 못했다. 본 논문은 상의 상태와 제작 시기 를 조사하여 대체로 이들은 탑보다 적게는 50년, 많게는 500여 년 앞서 제작되었으며, 광배 가 결실되거나 상의 일부가 파손된 채 안치된 것이 많음을 확인했다. 파손된 옛 불상을 탑 안에 넣은 이유를 탐색하기 위해 唐宋전환기라 불리는 이 시기 두드러지게 보이는 佛事의 신경향을 주목했다. 개인적인 발원을 담은 소형 불상의 제작이 감소함과 동시에 불상이나 탑내 다양한 공양물을 넣는 불사가 크게 유행했으며, 파손되었을 뿐 아니라 제작된 지 오래되 어 발원의 의미가 희미해진 옛 불상을 매장한 관습이 그것이다. 파손된 불상을 수리하여 사 찰의 경내에 보관하거나 소형 금동불을 불전에 진열해 놓았던 唐 이전의 관습 대신 오래된 상들을 매장하는 것이 당시 중국 각지에서 유행했는데, 江浙 지역에서는 그러한 불교 교장 을 조성하는 대신 탑이라는 공간 안에 옛 금동불을 모아 넣었을 것으로 보았다.
        7,000원
        93.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, a simulation computerized crash analysis evaluation method through reverse engineering was applied to the Defender vehicle to systemize and simplify the certification of small-scale electric vehicles. The Defender vehicle was selected as a benchmarking vehicle that converts into an electric vehicle, and the layout of the frame and element analysis of individual parts were conducted through reverse engineering. To review the vehicle package layout, the fastening and assembly method for each part was analyzed referring to the Defender maintenance guide and parts list, and it was used for frame element technology analysis. In addition, collisions according to the main frame material and the shape of the crash box were analyzed, and various cases were analyzed through parameter study. As a result of the crash analysis, it was found that the mild steel main frame could not guarantee the safety of the vehicle in a fixed wall collision situation, and the ATOS material would increase the collision safety of the Defender relatively. Through the crash analysis according to the shape of the crash box, it was found that the strength of the crash box is too high compared to the main body, and this should be reflected in the design for small-volume production of multiple products.
        4,000원
        94.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The first step is to determine the principal dimensions of the design ship, such as length between perpendiculars, beam, draft and depth when accomplishing the design of a new vessel. To make this process easier, a database with a large amount of existing ship data and a regression analysis technique are needed. Recently, deep learning, a branch of artificial intelligence (AI) has been used in regression analysis. In this paper, deep learning neural networks are used for regression analysis to find the regression function between the input and output data. To find the neural network structure with the highest accuracy, the errors of neural network structures with varying the number of the layers and the nodes are compared. In this paper, Python TensorFlow Keras API and MATLAB Deep Learning Toolbox are used to build deep learning neural networks. Constructed DNN (deep neural networks) makes helpful in determining the principal dimension of the ship and saves much time in the ship design process.
        4,000원
        95.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, for the purpose of reducing the catch of small giant octopus in a net pot, an escape experiment of octopus was performed on five types of escape rings of different sizes. As a result of the experiment, the smallest giant octopus with a weight of 406 g was found to escape from an escape ring with a diameter of 30 mm or larger, and 592 g octopus, a weight similar to the octopus of the current minimum landing weight (600 g), escaped from an escape ring with a diameter of larger than 40 mm. An individual weight with 406 g becomes 39 mm when converted from a diameter of 25 mm circular escape vent; that is, the circumference to the inner diameter of the mesh. It can be inferred that the converted mesh size of 39 mm cannot escape. Logistic regression analysis was performed using a generalized linear model (GLM) to investigate the correlation between the ratio of escape ring size/Mantle diameter (R/MD) and the escape rate. As a result, it was found that there was a significant correlation between the R/MD ratio and the escape rate and that the higher the R/MD ratio, the greater the escape rate. As a result of logistic regression analysis, the R/MD value was denoted 0.520 with the 50% escape rate. In addition, it can be estimated to be about 50 mm when converted to the mesh size. Therefore, in this study, the diameter of the escape ring and the size of the escape possible of the octopus were experimentally considered. It was found that there was a significant correlation.
        4,000원
        96.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 시군구와 같은 소지역 수준의 인구추계에 대한 관심이 증대하고 있음에도 불구하고 방법론적 연구는 매우 제한적이다. 따라서 본 연구의 주된 목적은 관찰 데이터를 이용해 다양한 소지역 인구추계 방법의 특성을 비교 분석하는 것이다. 이를 위해 선행연구에 대한 검토를 바탕으로 소지역 인구추계로 활용될 수 있는 주요 방법론을 선정하였다. 선정된 방법론을 대상으로 인구추 계를 수행함에 있어 적용 가능한 세부 사항을 고려하여 20여 가지의 실행 방법으로 구분하였다. 각 방법에 대해 우리나라 시군구 단위로 2001-2010년의 데이터를 바탕으로 2020년까지의 인구를 추계하고, 그 결과를 분석하였다. 주요 연구 결과는 다음과 같다. 첫째, 총인구를 대상으로 전반적인 추계 수행성을 비교한 결과 절충 할당법과 이지역 코호트-요인법이 상당히 유사한 정도로 가장 우수한 것으로 나타났다. 둘째, 추계 결과를 인구구조 및 시공간적 이질성의 측면에서 세부적으로 따져본 결과 다른 특성들도 드러났다. 대체로 이지역 코호트-요인법의 결과가 우수하였지만 0-4세, 25-34세 인구에 대한 오차는 상대적으로 크게 나타났다. 추계 기간이 짧은 단기 추계(5년)에서는 절충 할당법이 가장 우수했지만 추계 기간 증가에 따른 오차 증가 폭은 이지역 코호트-요인 법이 가장 낮았다. 개별 시군구의 오차 간에 편차가 있는데, 10% 이상의 오차를 가진 시군구는 약 25%였다. 이들은 인구 이동의 시계열 변이가 크거나 추계기간 중 인구성장율이 달라진 경우가 많았다. 이 연구는 소지역 인구추계 방법의 경험적 근거를 제시하여 향후 수행될 다양한 소지역 인구추계에서 주요한 참고가 될 것으로 기대된다.
        5,100원
        97.
        2022.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해상에서 전복사고가 발생하면 선박이 복원성을 잃고 전복되는 과정에서 승선 하고 있던 선원의 사망․실종․부상 등 인명사고가 발생하는 동시에 전복에 따 른 선체 침수 및 침몰로 인해 선박 소유자는 엄청난 경제적 손실을 입게 된다. 따라서 동일한 전복사고가 발생하는 것을 방지하기 위해서는 현행 선박길이24미터 이상 어선에만 적용되는 복원성검사 및 만재흘수선 표시 규정에 대하 여, 허가받은 어업의 형태와 어구의 종류를 고려하여 총톤수 20톤 미만의 소형 어선으로 확대할 필요가 있다. 또한 기중기 등 조업에 사용하는 중량 어로설비 설치 유무에 따라 추가적인 복원성검사 및 만재흘수선을 표시하고, 사고선박에 대해서는 동일한 사고가 다시 발생하지 않도록 임시검사 규정을 강화하는 등 실질적이고 효과적인 검사 규정이 필요하다. 이에 따라 이 연구에서는 2017년부터 2021년까지 최근 5년간의 해양안전심판 원 재결서를 바탕으로, 자주 발생하고 있는 길이 24미터 미만의 소형어선 전복 사고 발생 원인과 소형어선 검사 규정의 문제점에 관한 연구를 통한 어선검사 규정 개선방안을 모색하였다.
        6,000원
        98.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We analyzed the hair microstructure of Korean small terrestrial mammals, such as Rodentia and Lagomorpha, to classify the characteristics of hair morphology. Micromys minutus showed a unicellular irregular type of medulla structures; on the other hand, the other mammals showed multicellular structures. Regarding the cuticular scale structures, the Rodentia species exhibited a narrow and broad diamond petal type, while the Lagomorpha species exhibited an elongated petal type. Interestingly, the hair cross-sections showed quite unique characteristics. We constructed hair identification keys to distinguish species with a single hair. The dichotomous key of Rodentia and Lagomorpha can be used for their behavioral ecology and dietary analysis of upper predators to serve as the basis for ecological research.
        4,000원
        99.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study analyzed small group interaction in the videoconferencing-mediated English class at a university in South Korea. Adopting the ‘affordance’ construct (van Lier, 2004) as a conceptual framework for interpreting small group work, the goals of the research are to 1) identify the types of linguistic affordances emerging in videoconferencing-mediated small group work and 2) examine learners’ perceptions and responses to the linguistic affordances. Data were collected from two major sources: 40 video recording files of small group observation and post-class interviews with four students. The paper analyzed 13 extracts selected from the transcription of the video recordings. The overall results of the research suggest that a range of linguistic affordances emerged through interaction and participants responded to the affordances they perceived in various ways. Three types of linguistic affordances were observed in the data: technology-generated affordances, learner-generated affordances, and learner-to-learner-generated affordances. The study findings have important implications for providing new insights into the operationalization of the affordance construct as well as advancing the understanding of the affordance perspective of L2 learning.
        6,300원
        100.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 5년간 발생한 해양사고를 분석한 결과, 소형선박은 전체 좌초사고의 77.0 %를 차지하고, 인명사상도 66.1%로서 매우 높았 다. 목포지방해양안전심판원은 2021년 72건을 재결하였고, 이중 좌초사건은 10건이었다. 그리고 좌초사건 중 8건은 소형어선에서 발생하 였다. 본 논문은 2021년 목포지방해양안전심판원에서 재결하였던 소형어선에서 발생한 8건의 좌초사고에 대해 분석하였다. 이 소형어선 의 좌초사고는 맑은 날씨에 시정이 2~4마일로 양호하고, 파고 1미터 이내로 양호한 해상상태에서 발생한 것을 파악되었다. 그리고 좌초사 고의 주요 원인은 피로에 따른 졸음 운항, 경계 소홀, 선위확인 소홀, GPS Plotter 과신, 해도도식 및 조석간만의 차에 대한 이해부족 등인 것으로 나타났다. 이에 소형어선의 좌초사고 저감을 위해 다음의 방안을 제시하였다. 첫째, 갑판부 항해당직 부원교육을 이수한 선원이 선장을 보좌하도록 하여야 한다. 둘째, 졸음 방지용 경보장치는 조타실에 설치하여야 한다. 셋째, GPS Plotter의 성능기준과 최신화를 위해 제도는 마련되어야 한다. 마지막으로, 소형어선 선장은 주기적으로 해도도식과 기초 지문항법을 숙지할 수 있도록 교육을 받아야 한다.
        4,000원
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