• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.3144-3154
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• 2024

The development of soluble boron-free (SBF) operation in the innovative Small Modular Reactor (i-SMR) requires effective strategies for managing excess reactivity over extended operational cycles. This paper introduces a practical approach to reactor core design for SBF operation in i-SMR, emphasizing the use of gadolinia burnable absorbers (BA). The study investigates the feasibility of Highly Intensive and Discrete Gadolinia/Alumina Burnable Absorber (HIGA) rods for controlling excess reactivity sustainably. Through comprehensive analysis and simulations, the reactivity behavior with varying quantities of HIGA rods is examined, leading to the development of optimized fuel assembly designs. Furthermore, the integration of HIGA rods with integral gadolinia BA rods is discussed to enhance reactivity control and operational flexibility further. This approach utilizes the spatial self-shielding effect of gadolinia for extended reactivity management, crucial for stable and efficient reactor performance. The paper thoroughly addresses core design considerations, including fuel assembly configurations and control rod patterns, to ensure safety and performance in initial and reload cycles. This research advances the development of SBF operation in i-SMR by offering practical reactivity management solutions.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.60.1-60.1
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• 2015

High energy photons and mechanical energy produced by the process of star formation result in copious FIR molecular and atomic lines, which are important coolants of the system. Photons thermally or mechanically induced could dissociate water in the dense envelope to change relative abundances among the species of O, OH, and H2O. Here we analyze OH emission lines toward embedded young stellar objects (YSOs) observed as part of the Herschel open time key program, 'Dust, Ice, and Gas In Time (DIGIT)' in order to study the physical conditions of associated gas and the energy budget loaded on the OH line emission. According to our analysis of the Herschel/PACS spectra, OH emission peaks at the central spaxel in most of sources, but several sources show spatially extended emission structures. In the extended emission sources, the distribution of OH emission is correlated with that of [OI] emission and extended along the outflow directions. Considering the diversity of source properties, ratios between detected OH lines are relatively constant among sources. In addition, each OH line has strong correlation with bolometric luminosity. In order to determine the physical conditions of YSOs, we adopt several methods for the analysis of the OH lines: rotational diagram, non-LTE LVG analysis, and a 2-D PDR code. From the simple LVG analysis, we find that the thermal solution with the dense ( > $10^7cm^{-3}$) and warm ( ~ 100 K) OH gas reproduces the ratios of detected OH lines. However, our self-consistent PDR 2-D model, which can deal with the IR-pumping effect from the central protostar as well as the warm dust in situ, cannot fit the observational results, suggesting that an irradiated shock model is necessary for a better interpretation.

• Structural Engineering and Mechanics
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• v.68 no.3
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• pp.299-312
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• 2018

In this paper, an extended finite element method is proposed to analyze both geometric and material non-linear behavior of general Functionally Graded Material (FGM) plate-shell type structures. A user defined subroutine (UMAT) is developed and implemented in Abaqus/Standard to study the elastoplastic behavior of the ceramic particle-reinforced metal-matrix FGM plates-shells. The standard quadrilateral 4-nodes shell element with three rotational and three translational degrees of freedom per node, S4, is extended in the present study, to deal with elasto-plastic analysis of geometrically non-linear FGM plate-shell structures. The elastoplastic material properties are assumed to vary smoothly through the thickness of the plate-shell type structures. The nonlinear approach is based on Mori-Tanaka model to underline micromechanics and locally determine the effective FGM properties and self-consistent method of Suquet for the homogenization of the stress-field. The elasto-plastic behavior of the ceramic/metal FGM is assumed to follow Ludwik hardening law. An incremental formulation of the elasto-plastic constitutive relation is developed to predict the tangent operator. In order to to highlight the effectiveness and the accuracy of the present finite element procedure, numerical examples of geometrically non-linear elastoplastic functionally graded plates and shells are presented. The effects of the geometrical parameters and the volume fraction index on nonlinear responses are performed.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.105-112
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• 1998

In this paper, we propose a ESP(Extended Scan Path) architecture for multi-board testing. The conventional architectures for board testing are single scan path and multi-scan path. In the single scan path architecture, the scan path for test data is just one chain. If the scan path is faulty due to short or open, the test data is not valid. In the multi-scan path architecture, there are additional signals in multi-board testing. So conventional architectures are not adopted to multi-board testing. In the case of the ESP architecture, even though scan path is either short or open, it doesn't affect remaining other scan paths. As a result of executing parallel BIST and IEEE 1149.1 boundary scan test by using the proposed ESP architecture, we observed that the test time is short compared with the single scan path architecture. By comparing the ESP architecture with single scan path responding to independency of scan path, test time and with multi-scan path responding to signal, synchronization, we showed that the architecture has improved results.

• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.407-417
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• 2010

In Basel II compliance, internal rating systems are allowed for banks to enhance the self control and the validation of the system are getting more important. The validation methods are composed of qualitative test and quantitative test, three basic standards of which are discriminatory power, stability and calibration. The aim of this article is to review the quantitative tests for calibration and find a new method for it. These methods for discrimination between forecasted PD and observed PD include binomial test, chi square test, Brier score, traffic lights approach, normal test and extended traffic lights approach. We introduce a modified extended traffic lights approach considering asset correlations.

• The Journal of Information Systems
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• v.26 no.3
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• pp.313-337
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• 2017

Purpose Financial technology, also known as FinTech, is conceptually defined as a new type of financial service which is combined with information technology and other traditional financial services like payments, investments, financing, insurance, asset management and so on. Most of the studies on FinTech services have been conducted from the viewpoint of technical issues or legal and institutional studies, and few studies are conducted from the health belief perspectives and security behavior approaches. In this regard, this study suggest an extended information protection behavior model. Design/Methodology/Approach The Health Belief Model (HBM), the Protection Motivation Theory (PMT), and the Technology Threat Avoidance Theory (TTAT) were employed to identify constructs relevant to information protection behavior of FinTech services. A new extended information protection behavior model in which the influence factors of information protection behavior (i.e., perceived susceptibility, perceived severity, perceived benefits, perceived barriers, perceived self-efficacy, subjective norms) affect perceived threats and perceived responsiveness positively, leading to information protection behavior of FinTech users eventually. This study developed an extended information protection behavior model to explain the protection behavior intention in FinTech users and collected 272 survey responses from the mobile users who had experiences with such mobile payments and FinTech services. Findings The finding of this study suggests that the influence factors of information protection behavior affect perceived threats and perceived responsiveness positively, and information protection behavior of FinTech users as well.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.5
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• pp.219-232
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• 2020

The slip-weakening model developed by Ohnaka and Yamashita is extended over the breakdown zone by equating the scaling relationships for the breakdown zone and the whole rupture area. For the extension, the study uses the relationship between rupture velocity and radiation efficiency, which was derived in the theory of linear elastic fracture mechanics, and the definition of f_max given in the specific barrier model proposed by Papageorgiou and Aki. The results clearly show that the extended scaling relationship is governed by the ratio of rupture velocity to S wave velocity, and the velocity ratio can be determined by the ratio of characteristic frequencies of a Fourier amplitude spectrum, which are corner frequency, f_c, and source-controlled cut-off frequency, f_max, or vice versa. The derived relationship is tested by using the characteristic frequencies extracted from previous studies of more than 130 shallow crustal events (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan. Under the assumption of a dynamic similarity, the rupture velocity estimated from f_max/f_c and the modified integral timescale give quite similar scale-dependence of the rupture area to that given by Kanamori and Anderson. Also, the results for large earthquakes show good agreement to the values from a kinematic inversion in previous studies. The test results also indicate the unavailability of the spectral self-similarity proposed by Aki because of the scale-dependent rupture velocity and the rupture velocity-dependent f_max/f_c; however, the results do support the local similarity asserted by Ohnaka. It is also remarkable that the relationship between the rupture velocity and f_max/f_c is quite similar to Kolmogorov's hypothesis on a similarity in the theory of isotropic turbulence.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.4
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• pp.199-206
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• 2018

In this study, numerical analysis is applied to a two - dimensional model for verifying the general finite element program, Abaqus' s extended finite element method(XFEM). The cohesive element model used in the existing research has a limitation in simulating the actual crack because of the disadvantage that the crack path should be predicted and the element should be inserted. For this reason, the extended finite element method(XFEM), which predicts the path of cracks based on the directionality and specificity of stress, is emerging as a new solution in crack analysis. The validity of the XFEM application was confirmed by comparing the cohesive element analysis with the XFEM analysis by applying the crack path to the self - evident two - dimensional model. Numerical analysis confirms stress distribution and stress specificity immediately before crack initiation and compares it with actual crack initiation path. Based on this study, it is expected that cracks can be simulated by performing actual crack propagation analysis of complex models.

• Journal of Families and Better Life
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• v.29 no.6
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• pp.9-25
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• 2011

This study was performed to explore the factors that affect debt-use intention of young defaulters. In addition, this study compares three models that predict the intention to use debt by young defaulters: the theory of reasoned action and two variations of it. Specifically, this study proposes an extended theory of reasoned action by introducing Ao in place of the cognitive structure in the theory of reasoned action. In addition, this study proposes Ao as an independent variable that acts on BI rather than a dependent variable. Self-administered questionnaires were completed by 196 young defaulters attending a credit management education session held by the Credit Counseling & Recovery Service in Kwang-ju, Korea. Based on the study, the conclusions are as follows: the extended theory of reasoned action as proposed in this article most suitably explained the intention to use debt by young defaulters. It was also found that young defaulters were affected by attitudes toward debt, attitudes toward using debt, and subjective norms. It is therefore suggested that an attitudinal message would change the behavior effectively for young defaulters. The findings appeared to support the usefulness of the extended theory of reasoned action and the role of Ao as an independent variable as proposed in this article to explain the intention to use debt by young defaulters. These findings have an important theoretical meaning in that they modify two existing attitude theories in the context of consumer behavior.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.285-295
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• 1990

The utilization of medical care services has been partly regionalized with the implementation of referral requirement by the government since July 1, 1989 when the health insurance coverage was extended to all the people. For the purpose of regionalization, the whole country has been primarily divided into tertiary care regions, and each of them again into secondary care regions. This study investigates the self-sufficiency for in-patient care services of secondary care regions focusing on why it varies among the regions. In doing so, analysis is performed to examine a model which embodies three sets of hypotheses as follows : 1) The regional self-sufficiency for medical care services would be subject to direct influences of regional characteristics, amount of available services and structural properties of regional medical care system ; 2) The regional characteristics would have indirect effects on the self-sufficiency which are mediated by medical care services ; and 3) The amount of available services would indirectly affect the self-sufficiency by influencing the structure of regional medical care system. The results of analysis were generally consistent with the model. The findings have some practical implications. The regional self-sufficiency for medical care services partly depends upon basic properties of each region which cannot be changed in a short period of time. Thus the self-sufficiency for medical care services can be improved mainly by health policy measures. In some of the regions the self-sufficiency for in-patient care services was much higher or lower than can be predicted from the bed-population ratio. Indication is that the allocation of health resources should be made considering a variety of factors bearing upon the supply of and demand for health care ; not on the basis of just a single criterion like the availability. The self-sufficiency of a certain region is related to not only its own characterstics but also the characteristics of neighboring regions. Therefore, attention should be also directed to the inter-regional relationships in health care when the needs for investment of health resources in a region are assessed. However, it should be noted that this study used the data collected before the referral requirement was imposed. A replication of this analysis using recent data would provide an evaluation of the impact on the self-sufficiency of the referral requirement as well as a confirmation of the findings of this study.