• Animal Systematics, Evolution and Diversity
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• v.18 no.2
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• pp.191-201
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• 2002

The first zoeal stage of Heptacarpus rectirostris (Stimpson, 1860) is re-described and illustrated in detail from laboratory-hatched material. The first zoea of H. rectirostris is more closely related to that of H. futilirostris than to H. camtschaticus, H. pandaloides, and H. geniculatus by having the pterygostomial spine and two anteroventral denticles on the carapace. The former two species, however, can be readily distinguished by the presence (H. futilirostris) or absence (H. rectirostris) of the posterolateral spine on the abdominal somites 4-5. A provisional key to the first zoeas of Heptacarpus for which larval studies are known from Korea and adjacent waters is provided. A list of larval descriptions within the Hippolytidae from Korea and adjacent waters is also included.

• Animal Systematics, Evolution and Diversity
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• v.31 no.3
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• pp.153-159
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• 2015

A terebellid polychaete identified as Pista shizugawaensis Nishi and Tanaka, 2006, whose species validity has been doubted, is newly reported from the southwest coast of Korea. Korean materials of the present study have several characteristics that agree well with the original description of P. shizugawaensis as follows: two pairs of branchiae on the 2nd and 3rd segments have tufts composed of many dichotomously branched filaments; the nephridial papillae are present on the 6th and 7th segments; the uncini on the anterior and middle thoracic segments possess only long-handled shafts while those on the posterior ones have additional short-handled shafts or lacking shafts; the notosetae are broadly or narrowly winged capillary. The authors examined the taxonomic value of the presence of lateral lobes on the 5th and 6th segments, which has been known as a key characteristic feature of P. shizugawaensis in the classification of Pista species. In the present study, several characteristics such as the shape of notosetae, uncinial shafts in the thoracic segments, and the presence of thin narrow lateral lobes on the 4th segment are suggested as the specific characteristics that help to distinguish P. shizugawaensis from its congeners. A key to Pista species from Korean waters is also provided.

• Strategy21
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• s.39
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• pp.198-241
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• 2016

Aircraft carriers: are they national platforms to maximize national interest or just simply paper tigers to be little useful for states' development? To some states such as U.S., U.K, and France, aircraft carriers functioned as national assets which is indispensable to their interest. By contrast, Thailand's aircraft carrier was a dead platform which is useless to its national interest and India's ones were little used on the mission field. What is the mechanism leading to this difference? The key is whether states make aircraft carriers connected to overall national evolution when it comes to establishing military strategy and planning a long-term force structure. Put it another way, conditions to acquire them need to be analyzed regarding two variables-national status(prestige and economic power) and threat(mission)-for the future as well as in the present. The former acquired carriers under the condition of making them becoming national platforms which is balanced with their overall development. However, the latter simply bought them without carefully taking account of economic obstacles, e.g., the poverty rate, when it comes to force planning. At the same time, we should not neglect to identify that states of the former cases might have a hard time in maximizing their key interests if they did not have carriers. Accordingly, conditions on carriers' acquisition need to be carefully examined and a typological theory suggested here could shed light on this process. This theory shows that South Korea's status is eligible to have a necessary and sufficient condition to acquire carriers.

• Geomechanics and Engineering
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• v.11 no.3
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• pp.325-343
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• 2016

A total stress-based bounding surface model is developed to predict the undrained behaviour of saturated soft clays under cyclic loads based on the anisotropic hardening modulus field and bounding-surface theories. A new hardening rule is developed based on a new interpolation function of the hardening modulus that has simple mathematic expression and fewer model parameters. The evolution of hardening modulus field is described in the deviatoric stress space. It is assumed that the stress reverse points are the mapping centre points and the mapping centre moves with the variation of loading and unloading paths to describe the cyclic stress-strain hysteresis curve. In addition, by introducing a model parameter that reflects the accumulation rate and level of shear strain to the interpolation function, the cyclic shakedown and failure behaviour of soil elements with different combinations of initial and cyclic stresses can be captured. The methods to determine the model parameters using cyclic triaxial compression tests are also studied. Finally, the cyclic triaxial extension and torsional shear tests are performed. By comparing the predictions with the test results, the model can be used to describe undrained cyclic stress-strain responses of elements with different stress states for the tested clays.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.811-818
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• 2020

Y-containing CLAM steels were melted via vacuum induction melting and electroslag remelting. In this study, the evolution, microstructure, and mechanical properties of the alloy inclusions (ESR-1 (0 wt.% Y), ESR-2 (0.016 wt.% Y) and ESR-3 (0.042 wt.% Y)) were investigated. Further, the number of inclusions in ESRed steel was observed to obviously decrease, and the distributions were more uniform. The fine Y-Al-O inclusions (1-2 ㎛) were the main inclusions in ESR-2. The addition of Y affected the prior austenite grain size (PAGZ), increasing the tensile strength at test temperature. Low ductile-brittle transition temperature (DBTT) was obtained because of the fine PAGZ and dispersive inclusions. For the ESRed CLAM steel with 0.016 wt.% Y, the yield strengths were 621 MPa at 20 ℃ and 354 MPa at 600 ℃ in air. Further, the uniform elongation and elongation of the ESR-2 alloy were 5.5% and 20.1% at 20 ℃, respectively. Meanwhile, the DBTT tested using full-size Charpy impact specimen (55 cm × 10 cm × 10 cm) was reduced to -83 ℃.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1742-1760
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• 2017

Recent evolution in the open access internet technology demands that the identifying information of a user must be protected. Authentication is a prerequisite to ensure the protection of user identification. To improve Qu et al.'s scheme for remote user authentication, a recent proposal has been published by Huang et al., which presents a key agreement protocol in combination with ECC. It has been claimed that Huang et al. proposal is more robust and provides improved security. However, in the light of our experiment, it has been observed that Huang et al.'s proposal is breakable in case of user impersonation. Moreover, this paper presents an improved scheme to overcome the limitations of Huang et al.'s scheme. Security of the proposed scheme is evaluated using the well-known random oracle model. In comparison with Huang et al.'s protocol, the proposed scheme is lightweight with improved security.

• Korean Journal of Occupational Health Nursing
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• v.16 no.1
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• pp.58-66
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• 2007

Purpose: A national long-term care system for elderly and the disabled has its unique evolution in each country. Japan, Germany and the United States may be the typical examples of respective social insurance system. This paper reviews the counterpart examples of Japan, Germany and the United States and looks at their accumulated long-term care system experiences and personal care system under workers' compensation. Methods: Literature review and website searching were conducted. Key words as 'workers' compensation insurance', 'personal care benefit' and 'long term care' were used in searching the related literatures. Results: Though the personal care benefit under current Workers'Compensation in Korea is very similar to Japan's, the long-term care system of Korea is not as well established. Germany and the United States have the provision of personal care benefit for injured workers within long term care system. Conclusions: We recommend some key issues to take into account for improving personal care benefit system in workers' compensation in Korea as follows: providing a comprehensive coverage through the linkage of long term care, introducing an assessment & evaluation system for the appropriate benefits, establishing insurer's role for quality management of personal care service, and developing a policy for family caregivers.

• International Journal of High-Rise Buildings
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• v.1 no.3
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• pp.169-179
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• 2012

The development history, the current situation and the future of the performance-based seismic design of building structures in China are presented in this paper. Firstly, the evolution of performance-based seismic design of building structures specified in the Chinese codes for seismic design of buildings of the edition 1974, 1978, 1989, 2001 and 2010 are introduced and compared. Secondly, in two parts, this paper details the provisions of performance-based seismic design in different Chinese codes. The first part is about the "Code for Seismic Design of Buildings" (GB50011) (edition 1989, 2001 and 2010) and "Technical Specification for Concrete Structures of Tall Building", which presents the concepts and methods of performance-based seismic design adopted in Chinese codes; The second part is about "Management Provisions for Seismic Design of Outof-codes High-rise Building Structures" and "Guidelines for Seismic Design of Out-of-codes High-rise Building Structures", which concludes the performance-based seismic design requirements for high-rise building structures over the relevant codes in China. Finally, according to those mentioned above, this paper pointed out the imperfections of current performance-based seismic design in China and proposed the possible direction for further improvement.

• Nuclear Engineering and Technology
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• v.45 no.6
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• pp.767-790
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• 2013

MAAP4 is a computer code that can simulate the response of a light water reactor power plant during severe accident sequences, including actions taken as part of accident management. The code quantitatively predicts the evolution of a severe accident starting from full power conditions given a set of system faults and initiating events through events such as core melt, reactor vessel failure, and containment failure. Furthermore, models are included in the code to represent the actions that could mitigate the accident by in-vessel cooling, external cooling of the reactor pressure vessel, or cooling the debris in containment. A key element tied to using a code like MAAP4 is an uncertainty analysis. The purpose of this paper is to present a MAAP4 based analysis to examine the sensitivity of a key parameter, in this case hydrogen production, to a set of model parameters that are related to a Level 2 PRA analysis. The Level 2 analysis examines those sequences that result in core melting and subsequent reactor pressure vessel failure and its impact on the containment. This paper identifies individual contributors and MAAP4 model parameters that statistically influence hydrogen production. Hydrogen generation was chosen because of its direct relationship to oxidation. With greater oxidation, more heat is added to the core region and relocation (core slump) should occur faster. This, in theory, would lead to shorter failure times and subsequent "hotter" debris pool on the containment floor.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.26.1-26.1
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• 2010

In this talk we outline the current understanding of solar flares, mainly focusing on magnetohydrodynamic (MHD) processes. A flare causes plasma heating, mass ejection, and particle acceleration which generates high-energy particles. The key physical processes producing a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), formation of current-concentrated areas (current sheets) in the corona, and magnetic reconnection proceeding in a current sheet to cause shock heating, mass ejection, and particle acceleration. A flare starts with the dissipation of electric currents in the corona, followed by various dynamic processes that affect lower atmosphere such as the chromosphere and photosphere. In order to understand the physical mechanism for producing a flare, theoretical modeling has been develops, where numerical simulation is a strong tool in that it can reproduce the time-dependent, nonlinear evolution of a flare. In this talk we review various models of a flare proposed so far, explaining key features of individual models. We introduce the general properties of flares by referring observational results, then discuss the processes of energy build-up, release, and transport, all of which are responsible for a flare. We will come to a concluding viewpoint that flares are the manifestation of the recovering and ejecting processes of a global magnetic flux tube in the solar atmosphere, which has been disrupted via interaction with convective plasma while rising through the convection zone.