• Animal Systematics, Evolution and Diversity
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• v.29 no.2
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• pp.99-114
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• 2013

Phylogeographic and feeding ecological studies of seven terrestrial mustelid species (Carnivora, Mustelidae), the Japanese marten Martes melampus, the sable Martes zibellina, the Japanese badger Meles anakuma, the ermine or the stoat Mustela erminea, the Japanese weasel Mustela itatsi, the least weasel Mustela nivalis, and the Siberian weasel Mustela sibirica, representing four biogeographic patterns in the Japanese archipelagos (Hokkaido, Honshu-Shikoku-Kyushu, Tsushima, and Hokkaido-Honshu), were reviewed in order to clarify causes for the faunal assemblage processes of those mustelid species in Japan. Here, three main constraints were extracted as important factors on the mustelid assemblage. First, fundamental evolutionary differences maintained by niche conservatism in each ecologically diversified lineage ("evolutionary constraint") would enable the species to co-occur without any major problem (coexistence among Martes, Meles, and Mustela species). Second, "ecological constraints" would force two closely related species to be allopatric by competitive exclusion (Mu. itatsi and Mu. sibirica) or to be sympatric by resource partitions (Mu. erminea and Mu. nivalis). Third and most importantly, "geological constraints" would allow specific species to be embraced by a particular geographic region, primarily deciding which species co-occurs. The allopatric distribution of two Martes species in Japan would have been established by the strong effect of the geological separation in Tsugaru Strait. Elucidating both phylogeny and ecology of co-existing species in a community assemblage is important to know which species possess distinct lineage and which ecological traits are adapted to local environments, fulfilling the requirement of the field of conservation biology that endemism and adaptation should both be considered. The Japanese archipelagos would, therefore, provide valuable insight into the conservation for small carnivoran species.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.1-18
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• 2017

Metal fatigue is an important aging mechanism that material characteristics can be deteriorated when even a small load is applied repeatedly. An accurate fatigue evaluation is very important for component structural integrity and reliability. In the design stage of a nuclear power plant, the fatigue evaluations of the Class 1 components have to be performed. However, operating experience shows that the design evaluation can be very conservative due to conservatism in the transient severity and number of occurrence. Therefore, the fatigue monitoring system has been considered as a practical mean to ensure safe operation of the nuclear power plants. The fatigue monitoring system can quantify accumulated fatigue damage up to date for various plant conditions. The purpose of this paper is to describe the fatigue monitoring procedure and to introduce the fatigue monitoring program developed by the authors. The feasibility of the fatigue monitoring program is demonstrated by comparing with the actual operating data and finite element analysis results.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1253-1272
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• 2016

For a nonlinear control system, there are many uncertainties, such as the structural model, controlled parameters and external loads. Although the significant progress has been achieved on the robust control of nonlinear systems through some researches on this issue, there are still some limitations, for instance, the complicated solving process, weak conservatism of system, involuted structures and high order of controllers. In this study, the computational structural mechanics and optimal control theory are adopted to address above problems. The induced norm is the eigenvalue problem in structural mechanics, i.e., the elastic stable Euler critical force or eigenfrequency of structural system. The segment mixed energy is introduced with a precise integration and an extended Wittrick-Williams (W-W) induced norm calculation method. This is then incorporated in the market-based control (MBC) theory and combined with the force analogy method (FAM) to solve the MBC robust strategy (R-MBC) of nonlinear systems. Finally, a single-degree-of-freedom (SDOF) system and a 9-stories steel frame structure are analyzed. The results are compared with those calculated by the $H{\infty}$-robust (R-$H{\infty}$) algorithm, and show the induced norm leads to the infinite control output as soon as it reaches the critical value. The R-MBC strategy has a better control effect than the R-$H{\infty}$ algorithm and has the advantage of strong strain capacity and short online computation time. Thus, it can be applied to large complex structures.

• Nuclear Engineering and Technology
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• v.16 no.1
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• pp.36-46
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• 1984

Studied are the statistical thermal design (STD) methods that have been developed to satisfy the design basis which protects a pressurized water reactor (PWR) core against departure from nucleate boiling (DNB) during normal operations and anticipated transients. The objective of the statistical thermal design is to quantify the thermal design margin and to remove any excess conservatism from the DNB ratio calculations through statistically combining design parameter uncertainties, while still maintaining a high level of core protection. This report describes and compares the STD methods developed by the two U.S. reactor vendors (Westinghouse and B & W). Included are the characteristics of STD, statistical treatment of uncertainties, DNB design limit development methodology and the sample application of the STD technique to core thermal design analysis. It is observed that the STD methods developed by the two vendors are similiar to each other in principle, but different in the treatment of the uncertainties associated with the design parameters. The statistical thermal design is found to significantly improve the thermal design margin.

• Nuclear Engineering and Technology
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• v.23 no.2
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• pp.183-199
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• 1991

Transient response of temperature distributions in a Pressurized Water Reactor (PWR) pressurizer vessel wall for the Inadvertent Auxiliary Spray transient has been analyzed with conservatism accounted for the resulting thermal stresses in the regions of the vessel wall which are wetted by the spray water droplets. In order to determine the forced convective heat transfer coefficient at the inner boundary surface of vessel wall where the droplets impinge on and flow down, the transient temperatures of spray droplets when they reach the inner surface of the vessel wall after travelling from the spray nozzle through the pressurizer interior space occupied with the saturated steam-noncondensable hydrogen gas mixture have been predicted. The transient temperature distributions in the vessel wall have been obtained by using the finite element method, and the typical results have been provided. It has been shown that the results of thermal analysis are consistent with representation of the input transient and have plausible physical meaning.

• Korean journal of communication and information
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• v.18
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• pp.7-36
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• 2002

This study is concerned with analysing complexity, flexibility and dynamism of social discoursive space. The developmental process of social discourse is analogous to that of a spatial structure of social discourse. Post-capitalist society has seen New-Liberalism and New-Conservatism have become dominant, resulting in the deterioration of the cultural politics of citizenship. It is argued that the position of otherness, in which those binary structures (inside/outside or centre/margin) collide and collapse, is where subversive discourse can emerge to dominant discursive power. Furthermore, it is necessary to democratize social discursive space, through which the Other becomes able to. participate in the social production, distribution and consumption of social discourse.

• Journal of Korean Clinical Nursing Research
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• v.18 no.2
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• pp.215-227
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• 2012

Purpose: This study was conducted to examine clinical nurses' perceptions on the nursing organizational culture and investigate the differences in their perceptions according to age groups in South Korea. Methods: Participants were 1,087 nurses from 25 general hospitals in South Korea. Data were collected from July 29 to September 30 in 2011, and were analyzed using descriptive statistics, ANOVA with $Scheff{\grave{e}}$ test, and factor analysis. Results: Nurses perceived nursing as an excellent professional job which progresses continually. Autonomy and individualized reward to their professional work, however, were reported not-satisfactory to them. They agreed that nurses are punctual, polite, honest, and responsible, while disagreeing in competitiveness. There were differences in perceiving cultural factors according to age groups. The subjects in their over 40s perceived 'professionalism', 'normative', 'strictness', 'rightfulness', and 'community spirit' strongly, while nurses in their 20s perceived 'conservatism' highly. Also, nurses' perception on the organizational commitment and job satisfaction were high in over 40s while turnover intention was high in other groups. Conclusion: Nurse managers need to assess the perception on nursing organizational culture in order to improve nursing work environment better. In addition, it is necessary to take into account seriously the generation gap to build supportive nursing organizational culture.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.524-531
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• 2004

To investigate relevance of the definition of the reference stress to estimate J and $C^{*}$ for surface crack problems, this paper compares FE J and $C^{*}$ results for surface cracked pipes with those estimated according to the reference stress approach using various definitions of the reference stress. Pipes with part circumferential inner surface crack and finite internal axial crack are considered, subject to internal pressure and global bending. The crack depth and aspect ratio are systematically varied. The reference stress is defined in four different ways using (i) the local limit load, (ii) the global limit load, (iii) the global limit load determined from the FE limit analysis, and (iv) the optimized reference load. It is found that the reference stress based on the local limit load gives overall excessively conservative estimates of J and $^{*}$. Use of the global limit load clearly reduces the conservatism, compared to that of the local limit load, although it can provide sometimes non-conservative estimates of J and $^{*}$. The use of the FE global limit load gives overall non-conservative estimates of J and $^{*}$. The reference stress based on the optimised reference load gives overall accurate estimates of J and $^{*}$, compared to other definitions of the reference stress. Based on the present finding, general guidance on the choice of the reference stress for surface crack problems is given.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1741-1751
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• 2004

It is commonly requested that the steam generator tubes wall-thinned in excess of 40% should be plugged. However, the plugging criterion is known to be too conservative for some locations and types of defects and its application is limited to a single crack in spite of the fact that the occurrence of multiple through-wall cracks is more common in general. The objective of this research is to propose the optimum failure prediction models for two adjacent through-wall cracks in steam generator tubes. The conservatism of the present plugging criteria was reviewed using the existing failure prediction models for a single crack, and six new failure prediction models for multiple through-wall cracks have been introduced. Then, in order to determine the optimum ones among these new local or global failure prediction models, a series of plastic collapse tests and corresponding finite element analyses for two adjacent through-wall cracks in thin plate were carried out. Thereby, the reaction force model, plastic zone contact model and COD (Crack-Opening Displacement) base model were selected as the optimum ones for assessment of steam generator tubes with multiple through-wall cracks. The selected optimum failure prediction models, finally, were used to estimate the coalescence pressure of two adjacent through-wall cracks in steam generator tubes.

• Journal of the Korea Society of Computer and Information
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• v.18 no.6
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• pp.9-19
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• 2013

This paper deals with fuzzy $H_{\infty}$ filtering problem of discrete-time nonlinear Markovian jump systems with state and output time delays. The purpose is to design fuzzy $H_{\infty}$ filter such that the corresponding estimation error system with time delays and initial state uncertainties is stochastically stable and satisfies an $H_{\infty}$ performance level. A sufficient condition for the existence of fuzzy $H_{\infty}$ filter is given in terms of matrix inequalities. In order to relax conservatism, a stochastic mode dependent fuzzy Lyapunov function is employed. The Lyapunov function not only is dependent on the operation modes of system, but also includes the fuzzy membership functions. An illustrative example is finally given to show the applicability and effectiveness of the proposed method.