• Journal of Technology Innovation
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• v.6 no.2
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• pp.80-100
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• 1998

The application of computers and information technologies progressed with remarkable pace has paved the way for technological innovation toward the efficient integration of various functions in a manufacturing system. Actually it is observed that the greater part of manufacturing companies already initiated significant efforts to integrate information systems and attained the level of integration to some extent. The purpose of this paper is to clarify the strategic direction that manufacturing firms are pursuing through integrating information systems. Using the extensive data gathered from Japanese manufacturers, it is attempted to find the differences in competitive priorities and action programmes between the companies with high and low-level system integration. Our empirical data reveals that the manufacturers with highly integrated system are focusing their competitive capabilities on the rapid design change and new product introduction, and accordingly they place a greater emphasis on the action programmes related to design, process and quality improvement. As a conclusion, highly integrated firms tend to pursue new product development strategy more intensively, thereby they want to be a preemptor in the new market through exploiting technological advantages of integrated manufacturing system.

• ETRI Journal
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• v.33 no.1
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• pp.13-17
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• 2011

A highly miniaturized on-chip $180^{\circ}$ hybrid employing periodic ground strip structure (PGSS) was realized on a silicon radio frequency integrated circuit. The PGSS was placed at the interface between $SiO_2$ film and silicon substrate, and it was electrically connected to top-side ground planes through the contacts. Owing to the short wavelength characteristic of the transmission line employing the PGSS, the on-chip $180^{\circ}$ hybrid was highly miniaturized. Concretely, the on-chip $180^{\circ}$ hybrid exhibited good radio frequency performances from 37 GHz to 55 GHz, and it was 0.325 $mm^2$, which is 19.3% of a conventional $180^{\circ}$ hybrid. The miniaturization technique proposed in this work can be also used in other fields including compound semiconducting devices, such as high electron mobility transistors, diamond field effect transistors, and light emitting diodes.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.159-165
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• 2009

In this study, using a periodical ground structure(PGS) on GaAs monolithic microwave integrated circuit(MMIC), transmission line with a high isolation characteristic was developed for application to compact signal/bias lines of highly integrated MMIC. And the origin of the high isolation characteristic was theoretically investigated. The high isolation characteristic was originated from a resonance between adjacent microstrip lines employing PGS. With only a spacing of $20{\mu}m$, the coupled microstrip line employing PGS showed an isolation value of -47 dB at 60 GHz. The frequency range for high isolation was easily controlled by changing the PGS structure. Above results indicate that microstrip lines employing PGS are very useful for application to compact signal/bias lines of highly integrated MMIC requiring a high isolation characteristics between lines. In addition, equivalent circuit employing closed-form equation for the coupled line with PGS was also extracted.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.79-83
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• 2014

Dye-sensitized solar cells (DSSCs) are applied in the emerging fields of building integrated photovoltaic and electronics integrated photovoltaic like small portable power sources as demands are increased with characteristic advantages. Highly flexible dye-sensitized solar cells (DSSCs) prepared on single stainless steel mesh were proposed in this paper. Single mesh DSSCs structure utilizing the spraying the chopped glass paper on the surface treated stainless steel mesh for integrating the space element and the electrode components, counter electrode component and photoelectrode component were coated on each side of the single mesh. The fabricated single mesh DSSCs showed the energy-conversion efficiency 0.50% which show highly bendable ability. The new single mesh DSSCs may have potential applications as highly bendable solar cells to overcome the limitations of TCO-based DSSCs.

• Journal of Power Electronics
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• v.14 no.2
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• pp.257-264
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• 2014

A novel converter-free AC LED driver that is highly resistant to the fluctuation of AC voltage is proposed in this study. By removing large passive components, such as the bulky capacitor and the large-value inductor, the integration of the driver circuit is enhanced while the driving current remains stable. The proposed circuit provides LED lamps with a driving current that can follow the sinusoid waveform to obtain a very high power factor (PF) and low total harmonic distortion (THD). The LED input current produced by this driving current is insensitive to fluctuations in the AC voltage. Users will thus not feel that LED lamps are flashing during the fluctuation. Experiment results indicate that the proposed system can obtain PF of 0.999 and THD as low as 3.3% for a five-string 6 W LED load under 220 V at 50 Hz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1064-1069
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• 2007

This paper proposes the highly miniaturized active $90^{\circ} power combiner for application to MMIC. Conventional passive $90^{\circ} power combiners can't be integrated on MMIC because of their very larger size. Therefore, the highly miniaturized $90^{\circ} power combiners are required for a development of highly integrated MMIC. For this paper, the highly miniaturized active $90^{\circ} power combiner employing InGaP/GaAs HBT was fabricated on GaAs substrate for application to highly integrated MMIC. A size of fabricated active $90^{\circ} power combiner was $2.42{\times}1.05$ mm, which was 2.2 % of conventional passive $90^{\circ} power combiner. The fabricated active $90^{\circ} power combiner showed a gain characteristic about 10 dB and a good phase-difference coupling characteristic of $-92.6^{\circ} than conventional passive $90^{\circ} power combiner at 2.4 GHz. The highly miniaturized active $90^{\circ} power combiner exhibited good RF performances comparable to conventional passive $90^{\circ} power combiners. This work is the first report of an active $90^{\circ} power combiner.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1525-1525
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• 1999

The main purpose of HITES(Highly Integrated Total Energy System) is to build and develop an integrated energy system for power system operational planning and analysis which consists of load forecast, economic generation schedule, stability analysis and relational database system. The HITES can be utilized to supply a stable electric power and operate KEPCO's power system facilities economically. This system was put into operation in 1999. This paper describes the main feature of the HITES, main functions, numerical methods adopted in this system and network configuration.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.567-574
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• 2016

We propose a highly birefringent and dispersion compensating photonic crystal fiber based on a double line defect core. Using a finite element method (FEM) with a perfectly matched layer (PML), it is demonstrated that it is possible to obtain broadband large negative dispersion of about -400 to -427 ps/(nm.km) covering all optical communication bands (from O to U band) and to achieve the dispersion coefficient of -425 ps/(nm.km) at 1.55μm. In addition, the highest birefringence of the proposed PCF at 1.55 μm is 1.92 × 10^-2 and the value of birefringence from the wavelength of 1.26 to 1.8 μm (covering O to U bands) is about 1.8 × 10^-2 to 1.92 × 10^-2. It is confirmed that from the simulation results, the confinement loss of the proposed PCF is always less than 10^-3 dB/km at 1.55 μm with seven fiber rings of air holes in the cladding.

• ETRI Journal
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• v.31 no.5
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• pp.598-600
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• 2009

A highly efficient and compactly integrated balanced power amplifier (PA) for W-CDMA handset applications is presented. To overcome the size limit of a typical balanced PA, a bulky input divider is integrated into a PA MMIC, and a complex output network is replaced with simple lumped-element networks. For efficiency improvement at the low output power level, one of the two amplifiers in parallel is deactivated and the other is partially operated with corresponding load impedance optimization. The implemented PA shows excellent average current consumption of 34.5 mA in urban and 56.3 mA in suburban environments, while exhibiting very good load-insensitivity under condition of VSWR=4:1.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.85-88
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• 1992

This paper describes the need of the Database which is designed built with data lot a highly Integrated system for power system planning and operation. The study also, deals plans for and designs of thr highly integrated systems in order to optimize coordination of security and economy of power system planning and operations, as well as to improve the efficiency of data handling