• Title/Summary/Keyword: Unavailability analysis

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Theoretical Structure Prediction of Bradykinin Receptor B2 Using Comparative Modeling

  • Nagarajan, Santhosh Kumar;Madhavan, Thirumurthy
    • Journal of Integrative Natural Science
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    • v.9 no.4
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    • pp.234-240
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    • 2016
  • Bradykinin receptor B2, a GPCR protein, binds with the inflammatory mediator hormone bradkynin. It plays an important role in cross-talk between the renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS). Also, it is involved in many processes including vasodilation, edema, smooth muscle spasm and pain fiber stimulation. Hence, studuying the structural features of the receptor becomes important. But the unavailability of the three dimensional structure of the protein makes the analysis difficult. Hence we have performed the homology modelling of Bradykinin receptor B2 with 5 different templates. 25 different homology models were constructed. Two best models were selected based on the model validation. The developed models could be helpful in analysing the structural features of Bradykinin receptor B2 and in pathophysiology of various disorders related to them.

Thermal hydraulic analysis of core flow bypass in a typical research reactor

  • Ibrahim, Said M.A.;El-Morshedy, Salah El-Din;Abdelmaksoud, Abdelfatah
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.54-59
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    • 2019
  • The main objective of nuclear reactor safety is to maintain the nuclear fuel in a thermally safe condition with enough safety margins during normal operation and anticipated operational occurrences. In this research, core flow bypass is studied under the conditions of the unavailability of safety systems. As core bypass occurs, the core flow rate is assumed to decrease exponentially with a time constant of 25 s to new steady state values of 20, 40, 60, and 80% of the nominal core flow rate. The thermal hydraulic code PARET is used through these calculations. Reactor thermal hydraulic stability is reported for all cases of core flow bypass.

A Study on Economic Ripple Effect and Export Connection Method of Food Industry (식품산업의 경제적 파급효과와 수출 연계 방안에 관한 연구)

  • Chai, Jong-Hun
    • International Commerce and Information Review
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    • v.12 no.1
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    • pp.225-250
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    • 2010
  • The purpose of this study is to grasp the ripple effect of food industry, which is rising as the prominent industry of the future and has a high forward & backward ripple effect, on domestic economy and other industries through Industrial Input-Output Analysis and suggest the export connection method for the development of food industry in the future. As an analysis result, it was found that the effect on product inducement and employment inducement was very high. Like that, it is necessary to establish export connection strategy to escape from narrow domestic market and advance into world market in order to develop food industry, which has a high ripple effect on domestic market. For the export connection of food industry, it is possible to enlarge overseas market demand of domestic food industry by providing domestic food companies with export-concerned information such as overseas export market information and food market information, advertising world market for domestic food industry actively through the globalization of Korea food, securing food processing technology, removing export unavailability risk through the export insurance policy and advertizing the safety of food industry through the reinforcement of food safety control standard and penalty standard.

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Modeling and Performance Analysis of Communication Channels for Multimedia System (멀티미디어 시스템의 통신 채널 모델링 및 성능분석)

  • Bang Suk-Yoon;Ro Cheul-Woo
    • The Journal of the Korea Contents Association
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    • v.5 no.1
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    • pp.147-155
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    • 2005
  • In this paper, communication channels for the transmission of multimedia packets are modeled and evaluated. The multimedia packet traffic characterized by on-off and MMPP process for voice and data, respectively, dynamic channel allocation, queueing of data packets due to unavailability of channels and dropping of queued data packets over timeout, and guard channel for voice packets are modeled. The performance indices adopted in the evaluation of SRN model includes blocking and dropping probabilities. The SRN uses rewards concepts instead of the complicate numerical analysis required for the Markov chain. It is shown that our SRN modeling techniques provide an easier way to carry out performance analysis.

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Risk-informed approach to the safety improvement of the reactor protection system of the AGN-201K research reactor

  • Ahmed, Ibrahim;Zio, Enrico;Heo, Gyunyoung
    • Nuclear Engineering and Technology
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    • v.52 no.4
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    • pp.764-775
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    • 2020
  • Periodic safety reviews (PSRs) are conducted on operating nuclear power plants (NPPs) and have been mandated also for research reactors in Korea, in response to the Fukushima accident. One safety review tool, the probabilistic safety assessment (PSA), aims to identify weaknesses in the design and operation of the research reactor, and to evaluate and compare possible safety improvements. However, the PSA for research reactors is difficult due to scarce data availability. An important element in the analysis of research reactors is the reactor protection system (RPS), with its functionality and importance. In this view, we consider that of the AGN-201K, a zero-power reactor without forced decay heat removal systems, to demonstrate a risk-informed safety improvement study. By incorporating risk- and safety-significance importance measures, and sensitivity and uncertainty analyses, the proposed method identifies critical components in the RPS reliability model, systematically proposes potential safety improvements and ranks them to assist in the decision-making process.

Identification of Unmet Healthcare Needs: A National Survey in Thailand

  • Chongthawonsatid, Sukanya
    • Journal of Preventive Medicine and Public Health
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    • v.54 no.2
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    • pp.129-136
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    • 2021
  • Objectives: This study examined demographic factors hampering access to healthcare at hospitals and suggests policy approaches to improve healthcare management in Thailand. Methods: The data for the study were drawn from a health and welfare survey conducted by the National Statistical Office of Thailand in 2017. The population-based health and welfare survey was systematically carried out by skilled interviewers, who polled 21 519 384 individuals. The independent variables related to demographic data (age, sex, religion, marital status, education, occupation, and area of residence), chronic diseases, and health insurance coverage. The dependent variable was the degree of access to healthcare. Multiple logistic regression analysis was subsequently performed on the variables found to be significant in the univariate analysis. Results: Only 2.5% of the population did not visit a hospital when necessary for outpatient-department treatment, hospitalization, or the provision of oral care. The primary reasons people gave for not availing themselves of the services offered by government hospitals when they were ill were-in descending order of frequency-insufficient time to seek care, long hospital queues, travel inconvenience, a lack of hospital beds, unavailability of a dentist, not having someone to accompany them, and being unable to pay for the transportation costs. Multiple logistic regression analysis showed that failure to access the health services provided at hospitals was associated with demographic, educational, occupational, health welfare, and geographic factors. Conclusions: Accessibility depends not only on health and welfare benefit coverage, but also on socioeconomic factors and the degree of convenience associated with visiting a hospital.

A Risk Impact Assessment According to the Reliability Improvement of the Emergency Power Supply System of a Nuclear Power Plant (원자력발전소 비상전력계통 강화 방안에 따른 리스크 영향 평가)

  • Jeon, Ho-Jun
    • Journal of the Korean Society of Safety
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    • v.27 no.5
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    • pp.224-228
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    • 2012
  • According to the results of Probabilistic Safety Assessment(PSA) for a Nuclear Power Plant(NPP), an Emergency Power Supply(EPS) system has been considered as one of the most important safety system. Especially, the interests in the reliability of the EPS system have been increased after the severe accidents of Fukushima Daiichi. Firstly, we performed the risk assessment and the importance analysis of the EPS system based on the PSA models of the reference plant, which is the Korean standard NPP type. Considering a portable Diesel Generator(DG) system as the reliability reinforcement of the EPS system, we modified the PSA models and performed the risk impact assessment and the importance analysis. Although the reliability of the potable DG could be about 20% of the reliability of the alternative AC DG, we identified that Core Damage Frequency(CDF) was decreased by at least 4.6%. In addition, the risk impacts due to the unavailability of the EPS system on CDF were decreased.

Review of Calculational Model for the Performance of CANDU-Type Nuclear Development and Parametric Study on the Fuel Performance (CANDU형 핵연료거동에 관한 계산모형의 검토 및 거동특성에 관한 변수적 연구)

  • Man Sung Yim;Un Chul Lee;Ho Chun Suk
    • Nuclear Engineering and Technology
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    • v.15 no.1
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    • pp.57-69
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    • 1983
  • The LWR fuel performance analysis computer code, FRAPCON-1, are evaluated to investigate the performance of CANDU fuel elements loaded in Wolsung-1 reactor. The FRAPCON-1 models of neutron flux depression in fuel and of fuel-to-cladding heat transfer are modified, and the validity of fission gas release model for CANDU fuel is evaluated. And the heavy water properties are provided in calculating the heat transfer coefficient between cladding and coolant. By using the modified code, FRAPCON-1-CSK, the sensitivity studies are carried out for Wolsung-1 fuel element design parameters. The performance analysis is also performed for Wolsung-l fuel elements. The calculated results are discussed in terms of. LWR fuel design criteria because of unavailability of CANDU fuel design criteria.

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The Effect of R&D Expenditure on Firm Output: Empirical Evidence from Vietnam

  • BINH, Quan Minh Quoc;TUNG, Le Thanh
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.6
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    • pp.379-385
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    • 2020
  • The effect of research and development (R&D) expenditure on firm output is an interesting topic, but hardly explored in developing countries due to the unavailability of data. This study investigates this topic in the context of Vietnam by utilizing a novel dataset of 343 firms listed on the Vietnam Stock Exchange in the 2010-2018 period. The effect of R&D expenditure is examined under the production function framework. In order to obtain the robustness of the quantitative results, we estimate the production function with two coherent techniques including the OLS and 2-SLS. An instrumental variable regression technique is adopted to avoid the endogeneity problem between R&D expenditure and other variables. In our empirical analysis, we find that R&D expenditure has a positive and significant impact on output growth. The finding is robust in both OLS and 2-SLS frameworks. Besides, the output elasticity to R&D expenditure of our result is much higher than the estimated elasticity of other countries. The results imply that a 1% increase in R&D expenditure in Vietnam will help to expand the output more than a 1% increase in R&D investment in other countries. The findings from our paper provide important implications for firm managers, investors, and policymakers in Vietnam.

A Study on Outage Probability Analysis of HVDC Converter Considering Spare Elements (HVDC 변환소의 여유요소(Spare)를 고려한 사고확률 분석에 관한 연구)

  • Oh, Ungjin;Choi, Jaeseok;Kim, Chan-Ki;Yoon, Yongbeum
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.11
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    • pp.1408-1414
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    • 2018
  • Recently, as a solution to the problem of maintaining system reliability, stability, and quality occurring worldwide, such as activation of smart grid and recognition of super grid and rapid grid interconnection of renewable energy sources HVDC(High Voltage Direct Current) will appear on the front of the electric power system. These concepts are also very important concepts in HVDC systems. When the HVDC system is linked to the existing power system, it is composed of AC/DC/AC conversion device, and these conversion devices are composed of many thyristors. These parts(Devices) are connected in a complicated manner, and they belong to the one with a higher failure rate. However, the problem of establishing the concept of failure rate of HVDC parts directly linked to economic efficiency and the understanding accompanying it are still insufficient. Therefore, in this paper, we establish the meaning of reliability in power system and try to develop a model to analyze and verify the failure rate data of HVDC based on this.