• Journal of the Korean Society for information Management
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• v.6 no.2
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• pp.87-103
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• 1989

In this study, A DDC online system was developed which provides subject access and browsing function for class numbers or subject terms. A knowledgebase of the DDC Schedules and Relative Index was designed for this purpose using IBM-PC. From the DDC 20th edition, subjects from 004 to 006, covering‘data processing’,‘computer science’‘programming and progrms’, and etc., were selected for this experiment. DDC schedules are represented as a frame structure which is apt to describe hierachical structures. This experiment, joining the DDC to the information retrieval environment of an online catalog, will contribute to the future of the online DDC system by providing possiblities for search strategies not feasible through the alphabetical approach of subject headings and keywords presently supported by online catalogs.

• Structural Engineering and Mechanics
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• v.64 no.1
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• pp.121-133
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• 2017

This paper proposes an analytical solution method for free vibration of curved functionally graded (FG) nonlocal beam supposed to different thermal loadings, by considering porosity distribution via nonlocal elasticity theory for the first time. Material properties of curved FG beam are assumed to be temperature-dependent. Thermo-mechanical properties of porous FG curved beam are supposed to vary through the thickness direction of beam and are assumed to be temperature-dependent. Since variation of pores along the thickness direction influences the mechanical and physical properties, porosity play a key role in the mechanical response of curved FG structures. The rule of power-law is modified to consider influence of porosity according to even distribution. The governing equations of curved FG porous nanobeam under temperature field are derived via the energy method based on Timoshenko beam theory. An analytical Navier solution procedure is used to achieve the natural frequencies of porous FG curved nanobeam supposed to thermal loadings with simply supported boundary condition. The results for simpler states are confirmed with known data in the literature. The effects of various parameters such as nonlocality, porosity volume fractions, type of temperature rising, gradient index, opening angle and aspect ratio of curved FG porous nanobeam on the natural frequency are successfully discussed. It is concluded that these parameters play key roles on the dynamic behavior of porous FG curved nanobeam. Presented numerical results can serve as benchmarks for future analyses of curve FG nanobeam with porosity phases.

• The Journal of the Acoustical Society of Korea
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• v.11 no.2
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• pp.50-58
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• 1992

To improve the quality of dwelling environment of domestic apartment house, it is required to establish the sound insulation standard and the performance evaluation method which is suitable to the domestic residential conditions. In this study, the properties of internal noisy sources of a single unit in apartment houses and the sound insulation performance of party walls are investigated and analyzed, as a primary step to the establishment of sound insulation standard. Based on these data, the differences in sound insulation index of each plane type are investigated along with their causes. Also, the factor which affect and decide the insulation performance are analyzed in an effort to improve the performance of party wall structures.

• Journal of Ocean Engineering and Technology
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• v.29 no.5
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• pp.359-365
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• 2015

A reliability analysis of the gravity-based foundation of anoffshore wind turbine was performed by considering the uncertainties of the design variables, including environmental loads. The limit state functions of the gravity-based foundation were defined using the response limits of the support structures suggested in the DNV standard. The wind load couldbe obtained using the GH_bladed software, and the wave load was calculated using the Morison equation. Then, the extreme distributions of the wind and wave loads were estimated by applying the peak over threshold (POT) method to the wind and wave load data. The probability distribution characteristics of the soil properties were defined with reference to a southwest coast geotechnical survey report. The reliability index was evaluated for each failure mode using a first-order reliability method.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.788-796
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• 1996

$TiO_2$ films prepared by RF magnetron sputtering, electron beam evaporation, ion assisted deposition (IAD) and sol-gel method are prepared on c-Si substrate and vitreous silica substrate respectively. From the transmission spectra of $TiO_2$ films on vitreous silica substrate in the spectral region from 190 nm to 900 nm, k($\lambda$) of $TiO_2$ is obtained. Using k($\lambda$) in the interband transition region the coefficients of the quantum mechanical dispersion relation of an amorphous $TiO_2$ and hence n($\lambda$) including the optically opaque region of above fundamental transition energy are obtained. The spectroscopic ellipsometry spectra of $TiO_2$ films in the spectral region of 1.5-5.0eV are model analyzed to get the film packing density variation versus i) substrate material, ii) film thickness and iii) film growth technique. The complex refractive index change of these $TiO_2$ films versus water condensation is also studied. Film micro-structures by SE modelling results are compared with those by atomic force microscopy images and X-ray diffraction data.

• Journal of Distribution Science
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• v.11 no.11
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• pp.5-11
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• 2013

Purpose - Considering corporate companies that are continually growing and bearing in mind the theory of agency, how confident can stakeholders be about their benefits in relation to managers' decisions? Previous research has indicated that the type of corporate governance can have an effective impact on companies' performance. The current study aims to investigate the impact of ownership structure on listed companies on the Tehran Stock Exchange. Research Design, Data, and Methodology - Through use of the correlation coefficient, the results indicate a positive correlation among the percentage of common stock held by board members, the percentage of non-executive board members, and separation of the positions of chairperson of the board of directors and managing director. Results - Based on the return on assets index, only the correlation between the proportion of ownership of the managing director and financial investment company ownership is significant. Conclusion -Managers can potentially make decisions that benefit themselves but are detrimental to shareholders' interests. Corporate governance is a factor that can mitigate agency costs. Corporate governance comprises the laws, regulations, structures, processes, cultures, and systems that lead to the achievement of objectives such as accountability, transparency, justice, and stakeholders' rights.

• Journal of KIISE:Databases
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• v.31 no.2
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• pp.99-107
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• 2004

Education and training are expected to change dramatically due to the combined impact of the Internet, database, and multimedia technologies However, the distance learning is often impeded by the lack of effective tools and system to manage and retrieve the lecture contents effectively. This paper introduces a prototype system called COVA that enables remote users to access specific parts of interest by contents from a large lecture database. COVA includes several novel techniques to achieve the content-based lecture retrieval in distance teaming: (1) The XML-based semistructured model to represent lecture contents; (2) The technique to build structural summaries, i.e., schemas, of XML lecture databases; (3) Index structures to speed up the search to find appropriate lecture contents.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.601-611
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• 2020

The study aims to investigate the impact of ownership structure on corporate voluntary disclosure in the listed companies of Bangladesh. While many studies on the impact of ownership structure on voluntary disclosure have looked at developed and developing countries, few studies have been carried out in a transition economy. Using a three-step relative voluntary disclosure index, the study applies a multivariate analysis on the cross-sectional data for the year 2018. The findings indicate that the quality of voluntary disclosure in transition economy is still below average but has improved compared to findings from the previous literature. We found a significant inverse relationship between corporate voluntary disclosure and public ownership, while no significant relationships between voluntary disclosure and institutional ownership, director ownership, and foreign ownership have been found. The empirical findings of the study will provide evidence to promote the voluntary disclosure characterized by the ownership structures. The findings have important implications for both local and foreign investors as they make their investment decisions especially related to a transition economy. Besides, the findings will assist, not only the corporate executives in rearranging their reporting paradigm, but also the regulators and governments in similar transition economy in adopting and formulating their corporate policies and strategies.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1061-1068
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• 2013

In this research, the design optimization of a composite sandwich has been performed for using as an airplane wing skin. Automated analysis framework for aero-structure interaction is used for calculating load data on the wing. For automated analysis framework, FLUENT is used for computational fluid dynamics (CFD) analysis. CFD mesh is generated automatically by using parametric modeling of CATIA and GAMBIT. A computational structure mechanics (CSM) mesh is generated automatically by the parametric method of the CATIA and visual basic script of NASTRAN-FX. The structure is analyzed by ABAQUS. Composite sandwich optimization is performed by NASTRAN SOL200. Design variables are thicknesses of the sandwich core and composite skin panel plies. The objective is to minimize the weight of the wing and constraints are applied for wing tip displacement, global failure index and local failure indexes.

• Structural Engineering and Mechanics
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• v.68 no.6
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• pp.721-733
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• 2018

The modal frequency responses of functionally graded (FG) sandwich doubly curved shell panels are investigated using a higher-order finite element formulation. The system of equations of the panel structure derived using Hamilton's principle for the evaluation of natural frequencies. The present shell panel model is discretised using the isoparametric Lagrangian element (nine nodes and nine degrees of freedom per node). An in-house MATLAB code is prepared using higher-order kinematics in association with the finite element scheme for the calculation of modal values. The stability of the opted numerical vibration frequency solutions for the various shell geometries i.e., single and doubly curved FG sandwich structure are proven via the convergence test. Further, close conformance of the finite element frequency solutions for the FG sandwich structures is found when compared with the published theoretical predictions (numerical, analytical and 3D elasticity solutions). Subsequently, appropriate numerical examples are solved pertaining to various design factors (curvature ratio, core-face thickness ratio, aspect ratio, support conditions, power-law index and sandwich symmetry type) those have the significant influence on the free vibration modal data of the FG sandwich curved structure.