• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2242-2246
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• 2009

In this paper, a homogeneous dual composite right/left-handed (D-CRLH) transmission line (TL) is proposed by using a defected ground structure (DGS) on the ground plane. In order to satisfy a homogeneity condition of metamaterial, a subwavelength unit cell is designed by way of a spiral DGS and a meander stub. From a dispersion diagram, it is expected that the frequency bands for the left-handed (LH) property is 3.5 - 4.4 GHz. At 3.8 GHz in the LH band, backward propagating phenomenon is observed from full-wave analysis. The experimental results show that the proposed TL has a stop-band in 1.75 - 3.6 GHz.

• Geomechanics and Engineering
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• v.16 no.3
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• pp.321-329
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• 2018

Classic braced walls use struts and wales to minimize ground movements induced by deep excavation. However, the installation of struts and wales is a time-consuming process and confines the work space. To secure a work space around the retaining structure, an anchoring system works in conjunction with a braced wall. However, anchoring cannot perform well when the shear strength of soil is low. In such a case, innovative retaining systems are required in excavation. This study proposes an innovative earth-retaining wall that uses in situ soil confined in dual sheet piles as a structural component. A numerical study was conducted to evaluate the stability of the proposed structure in cohesionless dry soil and establish a design chart. The displacement and factor of safety of the structural member were monitored and evaluated. According to the results, an increase in the clearance distance increases the depth of safe excavation. For a conservative design to secure the stability of the earth-retaining structure in cohesionless dry soil, the clearance distance should exceed 2 m, and the embedded depth should exceed 40% of the wall height. The results suggest that the proposed method can be used for 14 m of excavation without any internal support structure. The design chart can be used for the preliminary design of an earth-retaining structure using in situ soil with dual steel sheet piles in cohesionless dry soil.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.2
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• pp.69-76
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• 2000

A dual-modulus prescaler divides the input signal by one of the moduli according to the control signal. In this paper, a new fast dual-modulus prescaler is proposed. The proposed prescaler has a ratioed-NOR structure different from a conventional ratioed-NAND structure. The proposed one can operate at a higher speed by using parallely connected NMOSs instead of using series-connected ones. HSPICE simulation results using HYUNDAI 0.65(m 2-poly 2-metal CMOS process parameters show that the maximum operating frequency of the proposed dual-modulus prescaler is 2.8㎓ with power consumption of 40.7㎽ at 5V supply voltage at $25^{\circ}C$. The proposed dual-modulus prescaler can be utilized for the frequency-synthesis in cellular radio front-ends.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.278-283
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• 2004

Due to the complex arrangement of frequency plans and spatial overages in modern satellite communications, channels that are non-contiguous in frequency may be amplified by a single power amplifier and transmitted to the ground through one beam. In this paper, a dual-mode canonical filter with dual-passband is presented. The filter adopts dual-mode technique for mass and volume reduction. Canonical structure is adopted for maximum transmission zero realization. To validate the design technique, a 6-pole dual-mode canonical dual-passband filter for Ka-band(30/20 ㎓) satellite transponder is realized. The measured frequency response of the filter shows good agreement with the computed one.

• Steel and Composite Structures
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• v.37 no.4
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• pp.447-462
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• 2020

In this paper, a simplified seismic design method for low-rise dual frame-steel plate shear wall (SPSW) structures is proposed in the framework of performance-based seismic design. The dynamic response of a low-rise structure is mainly dominated by the first-mode and the structural system can be simplified to an equivalent single degree-of-freedom (SDOF) oscillator. The dual frame-SPSW structure was decomposed into a frame system and a SPSW system and they were simplified to an equivalent F-SDOF (SDOF for frame) oscillator and an equivalent S-SDOF (SDOF for SPSW) oscillator, respectively. The analytical models of F-SDOF and S-SDOF oscillators were constructed based on the OpenSees platform. The equivalent SDOF oscillator (D-SDOF, dual SDOF) for the frame-SPSW system was developed by combining the F-SDOF and S-SDOF oscillators in parallel. By employing the lateral force resistance coefficients and seismic demands of D-SDOF oscillator, the design approach of SPSW systems was developed. A 7-story frame-SPSW system was adopted to verify the feasibility and demonstrate the design process of the simplified method. The results also show the seismic demands derived by the equivalent dual SDOF oscillator have a good consistence with that by the frame-SPSW structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1458-1470
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• 2018

In this letter, a new dual-port Multiple-Input Multiple-Output (MIMO) antenna is introduced which has two independent signal feeding ports in a single antenna element to achieve smaller antenna volumes for the 5G mobile applications. The dual-port structure is implemented by adding a cross coupled semi-loop (CCSL) antenna as the secondary radiator to the ground short of inverted-F antenna (IFA). It is found that the port to port isolation is not deteriorated when an IFA and CCSL is combined to form a dual-port structure. The isolation property of the proposed antenna is compared with a polarization diversity based dual-port antenna proposed in the literature [9]. The operating frequency range is 3.3-4.0 GHz which is suitable for places where $4{\times}4$ MIMO systems are supposed to be deployed such as in China, EU, Korea and Japan at the band ${\times}$ (3.3 - 3.8GHz. The measured 6-dB impedance bandwidths of the proposed antennas are larger than 700 MHz with isolation between the feeding ports higher than 18 dB [1-2]. The simulation and measurement results show that the proposed antenna concept is a very promising alternative for 5G mobile applications.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.61-66
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• 1992

In this paper, a method for implementing software for the control system with dual structure in processor module is proposed and implemented to enhance its reliability. In this implementation the multi-tasking function which is provided by a real-time operating system is applied. The overall softwre is divided into five tasks and is performed in each of the dual processor module, independently. By this, the processor module with dual structure can achieve a control objective and fault diagnostics effectively. An experimental result shows that the backup processor module can be substituted for the primary processor module immediately when it happens to fail, because data relating the failure information are exchanged continuously done via shared memories.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.3
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• pp.14-20
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• 2011

This study aims at aligning multiple wafers to reduce wafer handling time in wafer processes. We designed a multilevel structure for a prealigner which can handle multiple wafer simultaneously in a system. The system consists of gripping parts, kinematic parts, vacuum chucks, pneumatic units, hall sensors and a DSP controller. Aligning procedure has two steps: mechanical gripping and notch finding. In the first step, a wafer is aligned in XY directions using 4-point mechanical contact. The rotational error can be found by detecting a signal in a notch using hall sensors. A dual prealigner was designed for 300mm wafers and constructed for a performance test. The accuracy was monitored by checking the movement of a notch in a machine vision. The result shows that the dual prealigner has enough performance as commercial products.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.11
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• pp.529-535
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• 2003

In this paper, we presents the characteristics of the new electrode structure in an AC Plasma Display Panel(PDP) that can generate dual mode discharges with a combination of short-gap and long-gap discharges. The experiment results show that the discharge voltage of the new electrode structure is mainly determined by short-gap discharge and the luminous efficiency is improved by 20% compared with the conventional electrode structure. The improvement of luminous efficiency is mainly caused by higher VUV generation and broader distribution from Ole ICCD camera measurements.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.76-80
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• 2007

In this paper, the PAE (Power Added Efficiency) and the linearity of the Doherty amplifier has been improved using dual bias control and PBG (Photonic BandGap) structure. The PBG structure has used to implement on output matching circuit and dual bias control has applied to improve the PAE of the Doherty amplifier at a low input level by applying it to a carrier amplifier. The Doherty amplifier using the proposed structure has improved PAE by 8% and 5dBc of IMD3 (3rd Inter-Modulation Distortion) compared with those of the conventional class AB amplifier. In addition to, it has been evident that the designed the structure has showed more than a 30% increase in PAE for flatness over all input power level.