• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.16-21
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• 2016

The purpose of this paper is to conduct ETA on 15 components of power installations: the DS/LBS, LA, MOF, CT, PT, A/V meter, VCB, OCR, COS, PF, Transformer, Condenser(C), Grounding, Cable and Connector. To achieve that, power installations work flow and its components are categorized. Based on performance, human, environmental, management, and safety, this paper drew Initiation events (IE) and End states (ES). ETA is applied to the main functions of each component, and the end states that may occur in one initiation event are suggested. In addition, detailed classification was performed to induce various end states on the basis of the suggested initiation events. If the suggested IEs and ESs are applied on the basis of power installations event cases, it is expected to prevent the same kinds of accident and operate power installations safely.

• Earthquakes and Structures
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• v.13 no.6
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• pp.599-611
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• 2017

This paper improves seismic fragility of a typical steel-concrete composite bridge with the deck-to-pier connection joint configuration at the concrete crossbeam (CCB). Based on the quasi-static test on a typical steel-concrete composite bridge model under the SEQBRI project, the damage states for both of the critical components, the CCB and the pier, are identified. The finite element model is developed, and calibrated using the experimental data to model the damage states of the CCB and the bridge pier as observed from the experiment of the test specimen. Then the component fragility curves for both of the CCB and the pier are derived and combined to develop the system fragility curves of the bridge. The uncertainty associated with the mean system fragility has been discussed and quantified. The study reveals that the CCB is more vulnerable than the pier for certain damage states and the typical steel-concrete composite bridge with CCB exhibits desirable seismic performance.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.803-808
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• 2012

We have implemented two-component spin-orbit relativistic effective core potential (SOREP) methods in an all-electron relativistic program DIRAC. This extends the capacity of the two-component SOREP method to many ground and excited state calculations in a single program. As the test cases, geometries and energies of the small halogen molecules were studied. Several two-component methods are compared by using spin-orbit and scalar relativistic effective core potentials. For the $I_2$ molecule, excitation energies of low-lying excited states agree well with those from corresponding all-electron methods. Efficiencies in SOREP calculations enhanced by using symmetries are also discussed briefly.

• Journal of the Korea Safety Management & Science
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• v.3 no.2
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• pp.123-131
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• 2001

Reliability calculation of a system is frequently required in industrial, military, and everyday life situations. For such a calculation, it is necessary to specify the configuration of components and subsystems, the failure mode of each component, and the states in which the system is classified as failed. In this paper, we are primary interested in the time to the first failure of a system. And we discuss failure probability of coherent system under various condition, especially focus on probability calculation of subsystem failure before system failure used by Bayes formula. Problem statement and general applications illustrated by several examples.

• Korean Journal of Materials Research
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• v.12 no.7
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• pp.528-532
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• 2002

Anodic $TiO_2$film on Ti substrate was fabricated at 180V in sulfuric acid solutions containing phosphoric acid and hydrogen peroxide. Effects of the anodizing conditions on the morphology of the oxide layers, and chemical states of the component elements of the layers were studied primarily using SEM, XRD, AFM, and XPS. The pores in the oxide layer was not uniform in size, shape, and growth direction particularly near the interface between the substrate and the oxide layer, compared with those of the surface layer. The formation of irregular type of pores seemed to be attributed to spark discharge phenomena which heavily occurred during increasing the anodic voltage. The pore diameter and the cell size increased, and the number of cells per unit area decreased with the increasing time. From the XPS results, it was shown that component elements of the electrolytes, P and S, existed in the chemical states of $PO_4^{-3}$ , $P_2$$O_{5}$, $SO_4^{-2}$ , $SO_3^{-2}$ , P, S, etc., which were penetrated from the electrolytes into the oxide layer during anodization.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.127-145
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• 2012

One of the most important and challenging steps in seismic vulnerability and performance assessment of highway bridges is the determination of the bridge component damage parameters and their corresponding limit states. These parameters are very essential for defining bridge damage state as well as determining the performance of highway bridges under a seismic event. Therefore, realistic damage limit states are required in the development of reliable fragility curves, which are employed in the seismic risk assessment packages for mitigation purposes. In this article, qualitative damage assessment criteria for ordinary highway bridges are taken into account considering the critical bridge components in terms of proper engineering demand parameters (EDPs). Seismic damage of bridges is strongly related to the deformation of bridge components as well as member internal forces imposed due to seismic actions. A simple approach is proposed for determining the acceptance criteria and damage limit states for use in seismic performance and vulnerability assessment of ordinary highway bridges in Turkey constructed after the 1990s. Physical damage of bridge components is represented by three damage limit states: serviceability, damage control, and collapse prevention. Inelastic deformation and shear force demand of the bent components (column and cap beam), and superstructure displacement are the most common causes for the seismic damage of the highway bridges. Each damage limit state is quantified with respect to the EDPs: i.e. curvature and shear force demand of RC bent components and superstructure relative displacement.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.2
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• pp.151-167
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• 1985

Generally, the same quality tobacco may give similar concentration of each chemical component. This research investigation was studied to obtain the differences in concentrations of volatile oil compounds in physically similar tobacco produced in different environment and managements-in Korea and in the United States. The flue-cured leaf tobacco produced in Korea and America was regraded to B3L and P3L by American grading system and analyzed for volatile oils relating to tobacco flavor and aroma. Sixty compounds of the more than 100 peaks distinguishable on the total neutral volatile oils were identified by G5-MS and quantified. Their concentrations are compared between B3 L and P3L produced in Korea and in the United States. The most volatile oil concentrations of B3 L and P3L grade tobacco arc higher in American than in Korean. Only a few components such as benzaldehyde, pulegonc, 4, 6, 9 - megastigmatriene - 3 - one, and coumaran are less in American.

• Journal of Korean Library and Information Science Society
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• v.48 no.3
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• pp.281-302
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• 2017

This study examined the differences in a searcher's mental states of a complex information search and retrieval task during information search process between the two groups: participants who were exposed to mental demand manipulation and those not exposed. Data from the experiments and questionnaires were analyzed. Based on qualitative approach and quantitative analyses, the results indicated that the participants exposed to mental demand required more thoughts; addressed negative emotions more often; reduced a searcher's efforts; and interrupted search performance than those not exposed. These results suggest that mental demand contributed to a searcher's perceived thought, emotion, effort, and performance, although these mental states differed in relative contribution of information search process. Significant differences were found between the two groups with respect to the component of mental demand, performance, and frustration of the NASA-TLX subjective cognitive load. These results have implications for search user interface design and information search systems among others.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.547-552
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• 1995

As an extension to the Kramers' restricted Hartree-Fock (KRHF) method [J. Comp. Chem., 13, 595 (1992)], we have implemented the Kramers' restricted configuration interaction (KRCI) program in order to calculate excited states as well as the ground state of polyatomic molecules containing heavy atoms. This KRCI is based on determinants composed of the two-component molecular spinors which are generated from KRHF calculations. The Hamiltonian employed in the KRHF and KRCI methods contains most of all the important relativistic effects including spin-orbit terms through the use of relativistic effective core potentials (REP). The present program which is limited to a small configuration space has been tested for a few atoms and molecules. Excitation energies of the group 14 and 16 elements calculated using the present KRCI program are in good accordance with the spectroscopic data. Calculated excitation energies for many Rydberg states of K and Cs indicate that spin-orbit terms in the REP, which are derived for the ground state, are also reliable for the description of highly excited states. The electronic states of the polyatomic molecule CH3I are probed from the molecular region to the dissociation limit. Test calculations demonstrate that the present KRCI is a useful method for the description of potential energy surface of polyatomic molecules containing heavy atoms.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.417-421
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• 2015

We analyzed 0.5-45 keV data of NGC 3227 observed by Suzaku six times between 2008 October 28 and December 2. The count-count plot between the 0.5-3 keV and 3-10 keV bands exhibits a clear break, separating the data into bright and faint phases. Applying the difference spectrum method and time-averaged spectral fits to the phase data, we found the presence of two kinds of variable primary X-rays, (1) a hard primary component with ${\Gamma}{\sim}1.7$ dominating in the faint phase and (2) a soft primary continuum with ${\Gamma}{\sim}2.4$ appearing in the bright phase, both affected by partial absorption. Considering their timing and spectral characteristics, component (1) is presumably identical to a Compton continuum in the low/hard state, while component (2) may correspond to the hard tail emission in the high/soft state, or compact-jet emission. In that case, an accretion ow onto the central super massive black hole in NGC 3227 can be interpreted to include the two different states.