• Journal of Ocean Engineering and Technology
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• v.24 no.6
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• pp.103-108
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• 2010

WIG crafts are high speed vessels with the features of a dynamic supported craft. These crafts, which are predominantly lightweight and operate at substantially greater speeds than conventional craft, could not be accommodated under traditional maritime safety instruments. WIG crafts inherently possess more hazard factors than conventional ships because of their relatively high speed, lightweight, and navigational characteristics, and an accident is likely to cause damage to the ship and a high loss of life. Because WIG crafts are composed of many systems and subsystems, the safety assessment of a WIG must use a commercial software system in the design stage. This paper reviews a safety assessment process and methodology proposed by the IMO interim guideline, which were developed in view of the configuration of WIG crafts. This safety assessment system was developed to fit the WIG's safety assessment process using a reliability analysis system widely used in commercial systems. The FHA was performed on the functional hazards of systems in the conceptual design stage.

• The Korean Journal of Applied Statistics
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• v.30 no.6
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• pp.983-991
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• 2017

High frequency time series are now prevalent in financial data. However, models need to be further developed to suit high frequency time series that account for intraday volatilities since traditional volatility models such as ARCH and GARCH are concerned only with daily volatilities. Due to $H{\ddot{o}}rmann$ et al. (2013), functional ARCH abbreviated as fARCH is proposed to analyze intraday volatilities based on high frequency time series. This article introduces fARCH to readers that illustrate intraday volatility configuration on the KOSPI and the Hyundai motor company based on the data with one minute high frequency.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.257-264
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• 2019

Recently, ITU-T recommends that FlexE, which allows the flexible configuration of Ethernet signals, be received by OTN for transparent transmission through OTN. To compensate for the difference in bit rate that can occur when mapping FlexE signals to OTN payload, an idle codeword is removed or inserted. However, the detailed functional blocks required to implement this method are not yet available. In this paper, based on the recent ITU-T requirements, a detailed functional block for OTN mapping of FlexE signals is proposed based on 400G class. In addition, based on the detailed functional blocks, mathematical analysis was performed to obtain the characteristics of removing and inserting idle code words, and the simulation results are shown.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.399-405
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• 2013

Two series of new green phosphorescent polymers bearing a bis(2-phenyl-pyridine)iridium(III)(dibenzoylmethane) [$(ppy)_2Irdbm$] complex were designed and synthesized. Poly-carbazole (PCbz) derivative or polyfluorene with pendant carbazole groups (PFCbz) were employed as host polymers for the iridium complex. The iridium complex monomer was copolymerized with the host monomers using varying monomer ratios via a Yamamoto coupling reaction. Efficient energy transfer from host to dopant unit was observed by increasing the ratio of the iridium guest in the copolymers. Electroluminescent devices with the configuration ITO/PEDOT:PSS/polymer/BmPyPB/LiF/Al were fabricated and characterized. The phosphorescent polymers composed of the iridium complex guest and polyfluorene with carbazole pendants as a host performed better than the polymers composed of the same guest and the main chain polycarbazole host. A maximum external quantum efficiency of 0.73%, a luminous efficiency of 1.21 cd/A, and a maximum luminance of 372 $cd/m^2$ were obtained from a device fabricated using one of the synthesized copolymers.

• Journal of the Korean housing association
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• v.27 no.6
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• pp.85-93
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• 2016

The spaces have a variety of sizes dependent upon their function and significance as well as their geometric shape. An architect Adolf Loos (1870-1933) had incorporated a correlation between the unconstrained formation of space into design. He had noticeably revealed the features of space that are unconstrained and mutually related with each other, for the space compositions among modern architects. This study is about to analyze the feature of space structure for houses of Adolf Loos through Space syntax which is the quantitative space analyzing method for the subject of his detached houses. These houses were emphasized for functional aspects of space without unnecessary decorations. Le Corbusier's Villa Savoye was analysed along with it to review a comparative point of view of his house's characteristic. Based on this, the features of the spatial structure of Loos' house were examined in conjunction with his views space as essence. A J-Graph and VGA for Adolf Loos' detached house revealed the structure's spatial characteristics in which the interior space is located deeply removed from exterior yet it is integrated as a whole. Also, it revealed that the experiments of the various spatial structures shown in Adolf Loos' detached house and European rationalist architects like Le Corbusier affected each other at the same time.

• Journal of the Korean Society of Combustion
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• v.21 no.4
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• pp.48-60
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• 2016

Experimental and numerical studies were conducted to investigate flame behaviors near flammable limits for downstream-interacting SNG-air premixed flames in a counter-flow configuration. The SNG fuel consisted of a methane, a propane, and a hydrogen with volumetric ratios of 91, 6, and 3%, respectively. The most appropriate priority for some reliable reaction mechanisms examined was given to the mechanism of UC San diego via comparison of lean extinction limits attained numerically with experimental ones. Flame stability map was presented with a functional dependencies of lower and upper methane concentrations in terms of global strain rate. The results show that, at the global strain rate of $30s^{-1}$, lean extinction boundary is slanted while rich extinction one is relatively less inclined because of the dependency of such extinction boundary shapes on deficient reactant Lewis number governed by methane mainly. Further increase of global strain rate forces both extinction boundaries to be more slanted and to be shrunk, resulting in an island of extinction boundary and subsequently one flame extinction limit. Extinction mechanisms for lean and rich, symmetric and asymmetric extinction boundary were identified and discussed via heat losses and chemical interaction.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1698-1701
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• 2006

In this research, fractal approach is applied to the realization of a virtual enterprise. Virtual enterprise is a temporarily built organization to cope with new business opportunity. It is composed of diverse business partners such as suppliers, manufacturers, customers, and service providers in value chains. Therefore, communication and interoperability problems between heterogeneous participants are one of the main concerns in developing collaboration models of a virtual enterprise. Fractal-based reference model can be a solution for this problem. The term 'fractal' is used to represent a participant of the value chains. There are many advantages when participants try to embody fractal-based collaboration model such as; (1) no restriction of inner configuration, (2) guarantee of autonomy, (3) easy implementation of interfaces, etc. Fractals are self-similar, however, this does not mean that they should have same configuration. In this paper, a fractal-based collaboration model for a virtual enterprise is proposed and described with (1) a formal formulation of fractal concept, (2) functional requirements and interfaces, and (3) a goal model as a driving force of the virtual enterprise.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.304-307
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• 2015

Carbon nanotubes (CNTs) have been widely accepted and used as the enhancer for polymer nano-composites due to their remarkable mechanical properties. Understandably, the CNT fiber-polymer matrix interface plays a major role in determining the properties of the CNT-polymer nano-composites. Here, using the LCAODFT Lab tool available on the EDISON Nano-Physics site, we performed first-principles density-functional theory calculations to determine the atomic configurations and binding energies of the CNTs in contact with polymers. For the polymer matrixes, we chose poly(acrylonitrile) (PAN), which is one of the most well-known polymer matrixes for the carbon nanofiber nanocomposites. Different chiralities and diameters of pristine CNTs were considered, and several PAN-CNT configurations were prepared based on the atomistic positions and directions of cyano group in PAN. The most favorable configuration of PAN was obtained when the PAN bound parallel to the surface of CNT. Our finding indicates the binding configurations are determined by the direction of the cyano group dominantly rather than the atomistic position of PAN, or the symmetry of CNTs. The result of increasing the length of CNT diameter suggests that PAN is inclinable to align evenly on the surface of relatively large size of CNT with the configuration parallel to the surface. These results obtained in this study will provide the starting point for the design of improved PAN-CNT composites for the next-generation ultra-strong and ultra-light carbon nanofibers.

• Progress in Superconductivity and Cryogenics
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• v.18 no.2
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• pp.42-47
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• 2016

A free-piston reciprocating expander is a device which operates without any mechanical linkage to a stationary part. Since the motion of the floating piston is only controlled by the pressure difference at two ends of the piston, this kind of expander may indispensably require a sophisticated active control system equipped with multiple valves and reservoirs. In this paper, we have suggested a novel design that can further reduce complexity of the previously developed cryogenic free-piston expander configuration. It is a simple replacement of both multiple valves and reservoirs by a combination of an orifice valve and a reservoir. The functional characteristic of the integrated orifice-reservoir configuration is similar to that of a phase controller applied in a pulse tube refrigerator so that we designate the one as a phase controller. Depending on the orifice valve size in the phase controller, the different PV work which affects the expander performance is generated. The numerical model of this unique free-piston reciprocating expander utilizing a phase controller is established to understand and analyze quantitatively the performance variation of the expander under different valve timing and orifice valve size. The room temperature experiments are carried out to examine the performance of this newly developed cryogenic expander.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1055-1060
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• 2013

The adsorption structures of threonine on the Ge(100) surface were investigated using core-level photoemission spectroscopy (CLPES) in conjunction with density functional theory (DFT) calculations. CLPES measurements were performed to identify the experimentally preferred adsorption structure. The preferred structure indicated the relative reactivities of the carboxyl and hydroxymethyl groups as electron donors to the Ge(100) surface during adsorption. The core-level C 1s, N 1s, and O 1s CLPES spectra indicated that the carboxyl oxygen competed more strongly with the hydroxymethyl oxygen during the adsorption reaction. Three among six possible adsorption structures were identified as energetically favorable using DFT calculation methods that considered the inter- and intra-bonding configurations upon adsorption onto the Ge(100) surface. These structures were O-H dissociated N dative inter bonding, O-H dissociated N dative intra bonding, O-H dissociation bonding. One of the adsorption structures: O-H dissociated N dative inter bonding was predicted to be stable in light of the transition state energies. We thus confirmed that the most favorable adsorption structure is the O-H dissociated N dative-inter bonding structure using CLPES and DFT calculation.