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        검색결과 20

        1.
        2023.11 구독 인증기관·개인회원 무료
        The Republic of Korea (ROK), as a member state of the IAEA, is operating the State’s System of Accounting for and Control (SSAC) and conducting independent national inspections. Furthermore, an evaluation methodology for the material unaccounted for (MUF) is being developed in ROK to enhance capabilities of national inspection. Generally, physical and chemical changes of nuclear material are unavoidable due to the operating system and structure of facilities, an accumulation of material unaccounted for (MUF) has been issued. IAEA developed statistical MUF evaluation method that can be applied to all facilities around the world and it mainly focuses on the diversion detection of nuclear materials in facilities. However, in terms of the national safeguard inspection, an evaluation of accountancy in facilities is additionally needed. Therefore, in this research, a new approach to MUF evaluation is suggested, based on the Guide to the Expression of Uncertainty in Measurement (GUM) that an evaluation of measurement uncertainty factors is straightforward. A hypothetical list of inventory items (LII) which has 6,118 items at the beginning and end of the material balance period, along with 360 inflow and outflow nuclear material items at a virtual fuel fabrication plant was employed for both the conventional IAEA MUF evaluation method and the proposed GUM-based method. To calculate the measurement uncertainty, it was assumed that an electronic balance, gravimetry, and a thermal ionization mass spectrometer were used for a measurement of the mass, concentration, and enrichment of 235U, respectively. Additionally, it was considered that independent and correlated uncertainty factors were defined as random factors and systematic factors for the ease of uncertainty propagation by the GUM. The total MUF uncertainties of IAEA (σMUF) and GUM (uMUF) method were 37.951 and 36.692 kg, respectively, under the aforementioned assumptions. The difference is low, it was demonstrated that the GUM method is applicable to the MUF evaluation. The IAEA method demonstrated its applicability to all nuclear facilities, but its calculated errors exhibited low traceability due to its simplification. In contrast, the calculated uncertainty based on the GUM method exhibited high reliability and traceability, as it allows for individual management of measurement uncertainty based on the facility’s accounting information. Consequently, the application of the GUM approach could offer more benefits than the conventional IAEA method in cases of national safeguard inspections where factor analysis is required for MUF assessment.
        2.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The air transport industry is experiencing unprecedented fluctuations in aviation demand through the Covid-19 pandemic, and is more focused than ever on maintaining and generating business profitability. During the pandemic, demand for air cargo has soared, and the conversion business from passenger aircrafts to freighters(P2F) is drawing attention as a new business in the aviation maintenance industry. This study derives important factors to be considered in order to successfully carry out the P2F project through a wide range of cases and related literature, and analyzes the relative importance of each factor using the analytic hierarchy process. Through a survey of 33 aviation maintenance experts with more than 20 years of field experience, the importance of main factors and their sub factors was determined and implications were drawn. As a primary result, in order to succeed in the P2F project, the main factors were identified in the order of skill, finance, and location. The most important sub factors for each main factors were identified in order of securing airframe modification skill, securing infrastructure construction cost, and creating P2F business complex and district. The quantified success factors suggested the critical direction for the successful development of Korea's P2F business, and presented viable and specific business strategies and implementation plans for each factors.
        4,500원
        3.
        2022.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연구는 참외 재배 지에서 흰가루병, 담배가루이 및 두점박이응애가 동시에 발생하였을 때 45, 40, 35°C (대조구)의 온도에서 측창으로 환기 처리 시, 온실 내 온 ․ 습도의 변화, 병충해 발생과 잎말림, 그리고 개화조절에 미 치는 효과를 검토하였다. 3월 3일 ‘히든파워’ 대목에 접붙여진 ‘알찬꿀’ 참외를 40cm 간격으로 격리상에 심었고, 위 에 언급한 병해충이 모든 처리구에서 발생한 6월 18일부터 7월 13일까지 처리하였다. 온실의 온도는 맑은 날에는 설정 온도 지점까지 증가되었고, 45°C 환기 처리에서 고온 고습이 약 9시간 동안 유지되었다. 주간 최고 기온과 최 저 상대습도 차이는 45°C 환기 처리에서 가장 높았다. 환기 처리 11일 후에는 흰가루병과 두점박이응애 피해가 45°C 환기 처리에서 거의 회복되었지만 40°C와 35°C에서는 그렇지 않았다. 처리 14일 후, 담배가루이와 두점박이 응애 밀도는 45°C에서 유의하게 감소하였으나 흰가루병 증상은 유의하게 감소하지는 않았다. 잎말림은 고온에서 유발되었으나 45°C에서도 심하지 않았다. 처리 26일 후, 새로 나온 줄기의 15 마디의 개화수를 조사한 결과, 45°C에 서 암꽃이 전혀 나오지 않았고 수꽃은 1.2개로 나타났다. 이상의 결과는, 고온기에 45°C의 고온에서 2-3주간 환기 처리는 온실 내부의 고온 고습을 유도하여 흰가루병, 담배가루이, 두점박이응애를 통제하고, 개화를 억제하여 참외 의 영양 생장을 회복할 수 있는 방법으로 사료되었다.
        4,000원
        4.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Military aircraft R&D projects require large-scale investment in cost and time, and involve a complex coordination process in decision-making. The R&D project manager should determine the development management priorities as accurately as possible and focus on R&D capabilities, thereby reducing the risks of the aircraft R&D project. To this end, this study aims to reduce R&D risk by prioritizing cost, schedule, and performance, which are basic management factors used in R&D project management in defense project management regulations. Analytic Hierarchy Process (AHP) is applied using a questionnaire for managers in charge of aviation R&D under the Defense Acquisition Program Administration. As a primary result, the importance of the factors that the aircraft R&D project manager should consider was derived in the order of performance, cost, and schedule, and the priorities of performance and cost in the lower layer were also identified. In addition, in order to provide practical risk management measures to aircraft R&D project managers, the results of analyzing 28 cases of US National Transportation Safety Board accidents were compared and analyzed with the AHP analysis results, and management measures suitable for the situation were specified.
        4,000원
        7.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates passenger-authored online reviews of airline services using social network analysis to compare the differences in customer perceptions between full service carriers (FSCs) and low cost carriers (LCCs). While deriving words with high frequency and weight matrix based on the text analysis for FSCs and LCCs respectively, we analyze the semantic network (betweenness centrality, eigenvector centrality, degree centrality) to compare the degree of connection between words in online reviews of each airline types using the social network analysis. Then we compare the words with high frequency and the connection degree to gauge their influences in the network. Moreover, we group eight clusters for FSCs and LCCs using the convergence of iterated correlations (CONCOR) analysis. Using the resultant clusters, we match the clusters to dimensions of two types of service quality models (Grönroos, Brady & Cronin (B&C)) to compare the airline service quality and determine which model fits better. From the semantic network analysis, FSCs are mainly related to inflight service words and LCCs are primarily related to the ground service words. The CONCOR analysis reveals that FSCs are mainly related to the dimension of outcome quality in Grönroos model, but evenly distributed to the dimensions in B&C model. On the other hand, LCCs are primarily related to the dimensions of process quality in both Grönroos and B&C models. From the CONCOR analysis, we also observe that B&C model fits better than Grönroos model for the airline service because the former model can capture passenger perceptions more specifically than the latter model can.
        4,800원
        10.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The design method for cumulative sum (CUSUM) control charts, which can be robust to autoregressive moving average (ARMA) modeling errors, has not been frequently proposed so far. This is because the CUSUM statistic involves a maximum function, which is in
        4,000원
        11.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Monitoring autocorrelated processes is prevalent in recent manufacturing environments. As a proactive control for manufacturing processes is emphasized especially in the semiconductor industry, it is natural to monitor real-time status of equipment throug
        4,000원
        12.
        2019.04 KCI 등재 서비스 종료(열람 제한)
        본 연구는 갑상샘 초음파에서 K-TIRADS 분류와 K-TIRADS 분류에 따른 Different risk group의 조합을 이용한 방법이 양성과 악성 결절의 감별진단에 유용한지를 평가하였다. 갑상샘 초음파를 시행한 210명을 대상으로 하였으며, 세침흡인세포검사 결과를 바탕으로 후향적인 분석을 하였다. 갑상샘 결절의 양성과 악성에 따른 K-TIRADS와 Different risk group의 점수체계의 차이 분석은 카이제곱 검정을 하였다. ROC 곡선 분석을 통해 악성 결절의 예측을 위한 K-TIRADS 점수와 Different risk group의 최적 cut off 값을 결정하였다. 양성과 악성 결절 군의 분류에 따른 K-TIRADS와 Different risk group의 차이검증 결과에서 각각 통계적으로 유의한 차이를 보였다(p=.001). ROC 곡선 분석에서 양성과 악성 결절의 예측을 위한 K-TIRADS에 따른 점수분류에서는 AUC 0.786, Cut-off value> 2를 나타내었으며, Different risk group에서는 AUC 0.640, Cut-off value> 2로 결정되었다(p=.001). 갑상샘 초음파에서 결절을 발견했을 때 양성과 악성 갑상샘 결절을 감별하는 데 도움을 주는 K-TIRADS에 따른 분류체계가 Different risk group에 따른 분류체계보다 갑상샘 결절의 감별진단에 도움을 줄 것으로 생각하며 K-TIRADS에 따른 분류체계를 적용하면, 불필요한 세포 검사를 줄일 수 있고, 악성 결절의 조기발견에 도움이 될 것으로 생각된다.
        13.
        2017.05 서비스 종료(열람 제한)
        Background : Korean mountain ginseng (Panax ginseng C.A. Meyer) are difficult to industrially apply because of its scarcity and high cost. Advances in plant biotechnology have made it possible to produce mountain ginseng on a large scale using adventitious root cultures in bio-reactors. This study was conducted to develop a cosmetic emulsion using ginsenoside and physiological activity - enhanced raw materials by fermentation process. Methods and Results : Wild ginseng adventitious roots were fermented with Pediococcus pentosaceus HLJG 0702 (KACC 81017BP). ginsenoside contents was analysed by using HPLC. Antioxidant activity was measured by DPPH and ABTS radical scavenging activity and whitening effect was measured by tyrosinase inhibitory activity. After microfluidizer processing was performed to prepare emulsions with homogenized particles, particle size and distribution were measured through a transmission electron microscop e(TEM). Particle stability compares pH, viscosity, light and zeta potential. When fermented with Pediococcus pentosaceus HLJG 0702, the highest change rates of Rg3, Rk1 and Rg5 were shown and the antioxidant activity was increased. The whitening effect was 73.2 ± 0.9% when treated at 100 ㎍/㎖, 1.5 times higher than the control. The optimum particle size and distribution were shown to be 418.0 ± 14.9 ㎚ for 6 times treatment with 0 - 10 times microfluidizer treatment. Stability was about 3% in pH, viscosity and light test. the zeta potential was found to be homogeneous at –33.33 mV. Conclusion : Pediococcus pentosaceus HLJG 0702 Fermented Wild ginseng adventitious roots were found to have effective ingredients and improved physiological activity. We have also developed emulsions that exhibit optimal particle size and distribution
        14.
        2016.10 서비스 종료(열람 제한)
        Background : The minor saponins produced by the hydrolysis of a major saponins sugar. The minor saponins has high absorption and efficacy compared to major saponin. The acid treatment, heat treatment and fermentation with minor saponin research has been actively conducted. This study was performed in order to investigate the bioconversion of ginsenoside Rg5 of fermented wild ginseng adventitious roots by using lactic acid bacteria. Methods and Results : 20g adventitious roots of ginseng was added to water (10-fold v/w). 10% (v/v) of lactic acid bacteria (Pediococcus pentosaceus HLJG0702[KACC 81017BP]) were inoculated with wild ginseng adventitious roots. For the fermentation process the inoculated samples were transferred to culture room for 1, 3 and 5 days. The fermented samples were dried at room temperature and extracted with 70% ethanol. Extract was concentrated completely at 50 ℃ and Rg5 was analysed by using HPLC. Results showed no significant difference the dry weight of non-fermented and fermented wild ginseng adventitious roots. During the fermentation process, the pH changed from 5.7 to 4.2. HPLC analysis showed higher ginsenoside Rg5 (39.588 mg/g) at 3 days. Conclusion : The fermentation of ginseng root can increase the Rg5 contents and minor saponin composition. This process may be used to enhance the minor saponin thereby increasing in fermented property of wild ginseng adventitious roots.
        15.
        2016.10 서비스 종료(열람 제한)
        Background : This study was carried out to survey the effect of IBA (indole-3-butric acid) concentration on root development characteristics in Viburnum dilatatum cuttings. Methods and Results : The cuttings were collected on July 28, 2016 from plants growing in Korea National Arboretum. Cuttings were treated with different IBA concentrations [0 (control), 10, 100, 1000, 2000 ㎎⋅L-¹] for 10 seconds. Rooting parameters (root number, the longest root length, root fresh weight, root dry weight, rooting percentage, and survival rate) were observed at 8 weeks after cuttings. Rooting percentage was 43, 33, 17, 47, and 40 % at 0, 10, 100, 1000, and 2000 ㎎⋅L-¹ of IBA, respectively. Root number (13.4) was highest under 1000 ㎎⋅L-¹ IBA. Root length (9.4 ㎝) and Root weight (fresh and dry) were highest under 1000 ㎎⋅L-¹ IBA. Conclusion : According to the results, 1000 ㎎⋅L-¹ IBA was the best treatment for increasing percentage rooting percentage and other root development characteristics of V. dilatatum cuttings.
        16.
        2016.05 서비스 종료(열람 제한)
        Background : Clematis trichotoma is a deciduous climber belonging to the family Ranunculaceae. This study was carried out to survey the effect of shading levels on growth characteristics in Clematis trichotoma seedling. Methods and Results : Seeds were collected from plants growing in the Mt. Kariwang Jeongseon, Gangwon-do in October 2013, and they were sown to 96 cell plug tray filled with Peatmoss (TKS-2) soil at March, 2015. The experiment was performed with four different shading levels (0, 30, 60, 90%) at July, 2015. According to the experiment, plant height was the highest under 90% of shading. It was found that fresh weight and dry weight of clematis trichotoma were the highest under 90% of shading. The leaf number was the highest under 30% of shading. The leaf number decreased as the shading level increased. Root number and length were the highest under 90% of shading. Conclusion : According to the results, Clematis trichotoma seedling showed the highest growth under 90% shading.
        17.
        2016.05 서비스 종료(열람 제한)
        Background : Scrophularia koraiensis is a herbaceous perennials belonging to the family Scrophulariaceae. This study was carried out to survey the effect of LED on root develop characteristics in Scrophularia koraiensis seedling. Methods and Results : Seeds were collected from plants growing in the Mt. Kariwang Jeongseon, Gangwon-do in September 2014, and they were sown to 128 cell plug tray filled with Peatmoss (TKS-2) soil at March, 2015. The experiment was performed with three different LED (Blue, Red, Blue + Red) at July, 2015. Morphological characteristics of root (total root length, root projet area, root surface area, root diameter and root volume) were analyzed with WinRHIZO software. Seedling root growth of scrophularia koraiensis was surveyed to be the highest at the Blue + Red LED in all measuring. Total root length was measured high in the order of Blue + Red, Red, Blue LED. Conclusion : According to the results, Scrophularia koraiensis seedling showed the highest root growth in Blue + Red LED.
        18.
        2014.09 서비스 종료(열람 제한)
        The isolated single coronary artery is a rare congenital anomaly, in which both coronary arteries arise from a solitary ostium. Diagnosis of coronary anomalies and identification of the exact anatomy of coronary arteries has significant clinical importance, hence, myocardial ischemia or sudden cardiac death is usually related to its course of anomalous coronary artery. Most patients with a single coronary artery are asymptomatic and have normal electrocardiogram and negative stress tests. However, if the patient has other structural abnormalities, for example, ventricular hypertrophy, the exam is determined. This report describes a case of single coronary artery, where the right coronary artery originated from the distal left circumflex artery in a patient with hypertrophic ardiomyopathy.