• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.1
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• pp.25-39
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• 2018

In this paper, an integrated analysis model for evaluating the underwater acoustic performance of the multilayered acoustic coatings containing visco-elastic composite layers with hollow glass microspheres is described. The model uses the effective medium theory considering the acoustic scattering and resonance effects of the inclusions. Also, the model incorporates the compressive deformation mechanism associated with hydrostatic pressure. The technique developed in this work was used as the acoustic layer design and performance analysis tools for the practical hull coatings and acoustic baffles in Korean next generation submarines.

• ETRI Journal
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• v.31 no.2
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• pp.225-227
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• 2009

A new planar metamaterial (MTM) with simultaneous negative values of permittivity (${\varepsilon}$) and permeability (${\mu}$) is proposed. Our MTM is composed of two identical copper patterns etched on both sides of dielectric laminate, which is very thin and easy to fabricate. Unlike conventional MTMs, the proposed structure shows a negative refractive index (NRI) behavior with respect to a normally incident wave. To explain the underlying principle of the NRI characteristics, an equivalent resonant circuit model based on surface current density distribution is investigated. An eigenmode analysis and a three-dimensional wave simulation for the stacked MTM prism are also performed to verify the existence of negative refraction. The experimental results from the transmission and reflection measurement ensure the validity of our design approach and show good agreement with the theoretically predicted effective medium parameters.

• Asia pacific journal of information systems
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• v.11 no.4
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• pp.155-173
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• 2001

This study identified CSFs(Critical Success Factors) for successful ERP system implementation in small and medium firms, and empirically tested relationship between CSFs and user performance. Survey questionnaires were distributed via email & fax to 142 firms that have implemented ERP systems. Out of 52 responded questionnaires, 46 data sets were available for statistical analysis with SPSSWin8.0. CEO's participation, vendor support & service, securing human resources, effective use of software, and hardware capacity were identified as CSFs from factor analysis. Among those factors, vendor support & service and effective use of software were related to user performance, and the relationship was shown to be statistically significant. Study results also showed that user performance of ERP system was significantly different among those surveyed firms when ERP system package products were used as a simple proxy measure of independent variable.

• Macromolecular Research
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• v.15 no.3
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• pp.211-215
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• 2007

Hybrid thin film nanostructures composed of metal nanoparticles (NPs) and self-assembled polymer films with different spatial distributions of NPs were analyzed by optical waveguide spectroscopy (OWS). Specifically, the dielectric constants were calculated using effective medium theory for the incorporation of 1 vol% Au NP into the block copolymer (BCP) films having a cylindrical nanodomain morphology. Three cases were considered: uniform distribution of NPs in the film; selective distribution of NPs only in the cylindrical domains; and segregation of NPs to the center of the cylindrical domains. The optical waveguide spectra derived from the calculated dielectric constants demonstrate the feasibility of experimentally distinguishing the composite nanostructures with different inner morphologies in the hybrid metal NP-BCP nanostructures, by the measurement of the dielectric constants using OWS.

• Current Optics and Photonics
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• v.7 no.3
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• pp.304-309
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• 2023

In this study, a binary dielectric annular nanoring lens is proposed to cover the full range of optical phase. The lens is designed numerically, based on the effective-medium theory. The performance of the proposed lens is verified for the cases of single-focal and dual-focal lenses. The efficiency of a single-focal lens is improved by 17.19% compared to a binary dielectric lens, and that of a dual-focal lens shows enhancements of 13.11% and 49.41% at the two focal points. This lens design can be applied to other optical components with axially symmetric structures.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.66
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• pp.59-67
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• 2001

This thesis is to research for analysis of ISO 9000 Quality Management System application status of small & medium-sized Industrial Companies. For this research, 10 companies certified by ISO 9000 standard were selected. By using an evaluation method and a software for analysis of application, this thesis compared, analyzed and evaluated the application status before and after certificate of ISO 9000, and identified the performance and difficulty of QMS application, and then proposed improvement methodology for ISO 9000 effective application.

• Journal of Computing Science and Engineering
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• v.6 no.2
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• pp.119-126
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• 2012

Machine-to-machine communications for healthcare is emerging for the benefit of humans. In addition to novel medium access, we provide a systematic view to look for ways to develop technology to accomplish this goal, and a thorough vision toward effective system and network design.

• Journal of the Korean Ceramic Society
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• v.15 no.2
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• pp.85-88
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• 1978

Influence of cooling atmosphere on the whiteness in white portland cement was studied. The effective composition of gaseous medium of cooling atmosphere is desirable less than 0.5% of $O_2$ and 0.5~1.5% of CO. When theclinker is quenched in nitrogen atmosphere, the color of clinker becomes bright pink. In a weakly reducing gaseous medium or vacuum, the absence of oxygen brings defects in crystal and transformation in the coordination of iron, and as a result, whiteness is raised.

• International Journal of Quality Innovation
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• v.4 no.1
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• pp.213-219
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• 2003

This paper proposes an efficient and effective BOM management scheme for small and medium manufacturing (SME) companies that produce automobile parts. Automobile part's manufacturers produce very various products due to various automobile characteristics such as types, colors, and options of cars. These products are classified into product groups with common parts and like this product groups with commonality are regarded as product family. This paper proposes a BOM data model for product family structures and implements the practical EXCEL-based BOM management system for real small and medium manufacturing (SU) companies that produces automobile parts.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.289-292
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• 2003

SME's (Small and Medium-sized Enterprises) have limited resources to build information systems on their own. We suggest what government need to do to support SME's, which includes establishing a one-stop service center, outsourcing of public service, and triggering strategy In order for the government support to be effective, it should serve SME's needs continuously and professionally.