• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.376-380
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• 2008

This paper deals with a performance analysis of real-time control systems, which engages DMR(dual modular redundancy) to detect transient errors and checkpointing technique to tolerate transient errors. Transient errors are caused by transient faults and the most significant type of errors in reliable computer systems. Transient faults are assumed to occur according to a Poisson process and to be detected by a dual modular redundant structure. In addition, an equidistant checkpointing strategy is considered. The probability of the successful task completion in a real-time control system where periodic checkpointing operations are performed during the execution of a real-time control task is derived. Numerical examples show how checkpoiniting scheme influences the probability of task completion. In addition, the result of the analysis is compared with the simulation result.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.664-669
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• 2003

This paper proposes a swing-arm type dual-stage actuator, which consists of a PZT actuator for fine motion and a VCM(Voice Coil Motor) for coarse motion, for SFF ODD(Small Form Factor Optical Disk Drive), in order to achieve fast access speed and precise track following control. We focus our attention on the design and control of the PZT actuator, because there have been a lot of previous researches related to the VCM and dual-stage actuators. Due to the dual cantilever structure, the PZT actuator can generate precise translational tracking motion at its tip where optical pickup is attached at, and the effect of hysteric behavior of the PZT element is reduced. The dynamic model of the PZT actuator is derived by using the Hamilton's principle, and verified by comparing with the experimental frequency response. The sliding mode control is designed in order to be robust against modeling uncertainties. Simulations and experimental results confirm the effectiveness of the suggested control scheme.

• 한국인터넷방송통신학회논문지
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• 제12권5호
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• pp.213-217
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• 2012

본 논문에서는 IEEE 802.11의 WLAN 대역을 포함하고 IEEE 802.16e의 이동형 WiMAX 규격을 동시에 포함하는 이중대역용 마이크로스트립 안테나를 설계하였다. 원하는 동작 주파수 대역에서 사용하지 않는 주파수의 간섭을 개선하여 임피던스 정합을 향상시키고, 간단한 제작 방식으로 소형화하였으며, 무지향성의 특성을 보였다. 제안된 구조는 하나의 안테나로 이중대역통신이 가능하여 설치비용 절감의 효과를 가져 올 것으로 사료된다.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.233-237
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• 2017

In this paper, a dual-band high frequency (HF) and ultra-high frequency (UHF) radio-frequency identification (RFID) tag antenna is presented that operates in the 13.56 MHz band as well as in the 920 MHz band. A spiral coil along the edges of the antenna substrate is designed to handle the HF band, and a novel meander open complementary split ring resonator (MOCSRR) dipole antenna is utilized to generate the UHF band. The dual-band antenna is supported by a single-feeding port for mono-chip RFID applications. The antenna is fabricated using an FR4 substrate to verify theoretical and simulation designs, and it has compact dimensions of $80mm{\times}40mm{\times}0.8mm$. The proposed antenna also has an omnidirectional characteristic with a gain of approximately 1 dBi.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.342-344
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• 2005

We have simulated a symmetric dual-gate TFT which has triple floating n+ channel to improve the on-current of the dual-gate TFT. We achieved a low hole concentration at the source and channel junction causes the improvement the potential barrier so that we observed the reduction of the kink-effect. In this paper, we observed the reduction of the kink-effect compared with the conventional single-gate TFT and the improvement of the on-current compared with the conventional dual-gate TFT.

• 전자공학회논문지B
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• 제33B권7호
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• pp.40-50
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• 1996

An unified compliant control algorithm to regulate the force by dual arms is proposed, where tow arms are treated as one arm in a kinematic viewpoint. The force error calculated form the information of two force/torque sensors attached to the end of each arm is transferred to minimum actuator coordinates, and then is distributed to total system actuator coordinates. The position adjustment at the total actuator coordinates is computed based on the effective computed based on the effective compliance matrix with respect to total actuator coordinates, which is obtained by coordinate transformation between the task coordinates and the total actuator coordinates. An experiment is carried out for dual arms with asymmetric kinematic structure to control an interaction force between manipulators and the environment. The performances of the proposed control algorithm are experimentally compared to those of dual arms employing master/slave scheme. The proposed compliant control algorithm not only ouperforms other algorithms, but also can be treated as an unified approach n the sense that it can be applied to arbitrary dual arm systems with general kinematic structures.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.219-220
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• 2006

In this paper, we designed and implemented the Dual Band Dipole Antenna with Tapered Microstrip Balun for WLAN Access Point. Two dipole antennas with different resonant frequency and the antenna structure combined additional line were implemented for dual band performance. In order to feed the balun current, the tapered microstrip balun was used. Produced the Dual Band Antenna shows a special quality. The quality is that all VSWR is less than 1.5 in the 2.4GHz and 5GHz frequency bands in 802.11 standards, and it profits not less than 1.7dBi having typical Dipole Antenna pattern the very "a form of 8"pattern and Omni-directional pattern.

• Carbon letters
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• 제7권4호
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• pp.277-281
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• 2006

In this study, in order to easily provide functional groups on the surface of carbon nanotubes, dual structural multiwalled carbon nanotubes which have crystalline graphite and turbostratic carbon wall were synthesized by modified vertical thermal decomposition method. Synthesized dual structural MWCNTs were characterized by FE-SEM, TGA, HR-TEM, Raman spectroscopy and BET specific surface area analyzer. The average innermost and outermost diameters of the synthesized nanotubes were around 45 and 75 nm, respectively. The large empty inner space and the presence of graphitic carbons on the surface may open potential applications for gas storage and collection of hazardous materials.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1250-1256
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• 2017

This paper proposes the design of microstrip patch antennas for dual-band polarization adjustment. The antenna has a multi-layer structure for dual-band operation, and each layer contains a resonating patch with surrounding strips separated into two parts. The antenna polarization is adjusted by varying the separated positions of the strips, while fixing other design parameters. To demonstrate the feasibility, an antenna sample with right-hand circular polarization is fabricated, and its antenna characteristics are measured in a full anechoic chamber. The operating principle of polarization adjustment in the dual frequency bands is also verified by observing near electromagnetic fields and the magnetic surface current density around the antenna.

• Journal of Power Electronics
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• 제16권1호
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• pp.133-141
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• 2016

This paper focuses on the development of a Five-Level Flying-Capacitor Dual Buck Inverter (FLFCDBI) based on the main circuit of dual buck inverters. This topology has been described as not having any shoot-through problems, no body-diode reverse recovery problems and the half-cycle work mode found in the traditional Multi-Level Flying-Capacitor Inverter (MLFCI). It has been shown that the flying-capacitor voltages of this inverter can be regulated by the redundant state selection within one pole. The voltage balance of the flying-capacitors can be achieved by charging or discharging in the positive (negative) half cycles by choosing the proper logical algorithms. This system has a simple structure but demonstrates improved performance and reliability. The validity of this inverter is conformed through computer-aided simulation and experimental investigations.