• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1042-1045
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• 2005

The feasibility of graphoepitaxial growth of compound semiconductor has been studied. Two kinds of substrates were prepared; one is smooth substrate, the other one is a periodic structured substrate. ZnO film was deposited on both substrates by sputtering, and thermal treatment was performed to improve the crystal quality and investigate the effect of the periodic structure. Atomic force microscopy (AFM) and photoluminescence (PL) were used to characterize the samples. As a result, very similarchange, the improvement of crystallinity, has been observed from both samples, except the sample annealed at the highest temperature. It implies the periodic structure affects the crystallinity of the films, and the graphoepitaxy of compound semiconductors is possible by using appropriate surface structure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.489-494
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• 2003

Vibration localization characteristics of open loop repeated structures with mistuning are investigated in this paper. Mistuning of a periodic structure often creates significant non-uniformity in vibration responses. As a result of the localization, critical fatigue problems often occur in repeated structures. Therefore, it is of great importance to predict the vibration response of the mistuned repeated structures accurately. In this paper, a simplified model for the open-loop repeated structure is introduced and dimensionless parameters which influence the localization characteristics are identified. The effects of the parameters on the localization characteristics are investigated through numerical study.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1412-1414
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• 2009

It is suggested that the light extraction efficiency of the display device can be improved by adoption of periodic array of sub-wavelength scale structures. The relief of the total reflection has been investigated using the rigorous coupled wave analysis (RCWA). Various shape of the sub-wavelength scale structure allowed to have non vanishing transmittance for the light rays with the incident angle bigger than the critical angle.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.40-46
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• 1993

In this paper, we design a multirate controller for a given multirate sampled-data system which has a periodic output measurement scheme. A sufficient condition for maintaining observability in multirate sampled-data systems is given first. The design strategy for disturbance rejection is proposed. The proposed controller has IMC structure, and can be deomposed into a disturbance estimator and the inverse of fast plants.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.107-108
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• 2009

• Journal of the Korean institute of surface engineering
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• v.15 no.1
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• pp.18-23
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• 1982

The microstructure of Watts and bright ni-ckel electrodepositss is correlated with pref-erred orientation. The characteristics lamellar structure of bright nickel was atributed to the periodic adsorption of organic additives and related to cyclic fluctuations in temper-ature.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.3
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• pp.142-146
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• 2014

In this paper, an antenna which has quad band in GSM/DCS/PCS/Bluetooth is proposed. This structure is designed with miniaturization for wide band characteristic based on monopole antenna and log-periodic toothed trapezoid patch antenna which has slots. To achieve multi-bandwidth is used the microstrip line on the substrate. An antenna size is $35mm{\times}20mm$ on FR-4(${\varepsilon}r=4.4$) ground substrate of $35mm{\times}75mm{\times}1mm$ size. And proposed antenna is satisfied with impedance bandwidth(VSWR ${\leq}$ 3). The simulated maximum radiation gain is 1.92 dBi, 3.26 dBi, 3.97 dBi at the center frequency of 0.92 GHz, 1.97 GHz, 2.45 GHz, respectively.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.101-107
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• 2003

In this study, we provide a single element log-periodic antenna that the feeding networks and array structures are aperture coupled and series dipole array type. We made the antenna for direct receiving the Moogoongwha satellite broadcasting signal. The transmission power was able to feed the patch dipole in series due to lay perpendicularly 8 series patch dipole on tapered slot. The patch dipole radiation pattern which fed in series power, make the main beam direction up $37^{\circ}{\sim}42^{\circ}$ within the BS/CS bandwidth. The main beam gain was measured 9.31~11.03 dBi. Using 32 elements to array the elements properly, we acquire $4{\times}8$ array structure on limited PCB board. As a result, it has been found that the new planar DBS antenna structure have high gain over 10dBi and acceptable elevation angle over 42 degree, and we can apply this result to commercial DBS reception antenna manufacturing.

• Journal of the Korea Furniture Society
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• v.19 no.5
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• pp.328-340
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• 2008

This study examined the characteristics of furniture design in the early Modernism that occurred in the early 20th Century through the relationship with modern arts. The furniture design of the early Modernism was established in the early 20th Century based on the simplicity and honesty of the Art and Crafts Movement and Anti-Historicism in Art Nouveau. During this period, the necessity of mass production became critical due to the radical industrialization and new social demands. In such periodic stream, the furniture design of the early modernism pursued simplicity and geometric beauty based on functionalism. The efforts to discover the fundamental structure of furniture were intensified. It was not limited to furniture design but was also exercised in the huge periodic transformation that progressed in every field of art including architecture. The Modernism art has also been connected to Cubism and spread into an abstract direction. While questioning the potential essence and progressing the study on genuine characteristics, the Modernism art tried to return things into their substantial looks and reorganize them conceptually, rather than reproducing external objects. The furniture that was secondary to a part of architecture and interior accessory transcended its decorative purpose. It pursued the structure to follow its fundamental purpose as furniture. Such tendency corresponded to the direction that Post-Modernism followed. Likewise, both art and design had the revivable and abstract characteristics based on the identical objective in ideology. For this reason, the formative and geometric characteristics of the early modernism furniture design have a mutual relationship with modern arts. Particularly, such tendency intensified and progressed through the Bauhaus in Germany. Based on such facts, this study proved that the early Modernism furniture design in the 20th Century tended to appear in common arts including the art and design according to the social demand of the huge periodic stream. Furthermore, the ideology that was adopted in art and design, as well as its formative characteristics, was examined through the mutual relationship of modern arts and design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.247-256
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• 1999

The leaky wave emanated from the dielectric-coated parallel-plate waveguide with finite periodic thick slot in its upper plate is investigated theoretically for H-polarization case. For this structure, fields in slot regions are expressed as a summation of the parallel-plate waveguide TM modes, and in other regions are expressed in the spectral domain by use of the inverse Fourier transform. Boundary conditions at the interfaces are enforced, and the simultaneous linear equations are derived. The influences of the slot width, slot thickness, thickness of a dielectric coating, and finite slot number on the radiation characteristics (phase constant, leakage constant, radiation pattern) are examined. The results of the finite periodic slot are compared with those of the infinite extent structure and good agreement has been found.