• ETRI Journal
• /
• v.35 no.3
• /
• pp.530-533
• /
• 2013

In this letter, a simple method for reducing the size of a dual-band planar inverted-F antenna (PIFA) is described. This method is based on a coupling capacitor connected in parallel to the PIFA feed conductor. The proposed antenna occupies a small ground clearance of $10mm{\times}5mm$ and is able to provide -10-dB impedance bandwidths of 120 MHz and 760 MHz for 2.45-GHz and 5.5-GHz wireless local area network applications, respectively. The measured antenna efficiencies are 71.8% and 73.6%, averaged over the 2.45-GHz and 5.5-GHz frequency bands, respectively.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2535-2539
• /
• 2003

The haptic system becomes an essential device in the area of tele-operation, video entertainment and medical operation. To control a haptic device, impedance control method is widely used, but force sensor costs so much that open-loop control method is usually preferred for commercial purpose. In this case, modeled/un-modeled dynamics affects the performance of device. In this paper, we present a new 3DOF five-link type haptic device that we can reduce the effect of device dynamics and compensate its dynamics. We also evaluate its performance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.432-437
• /
• 2002

DSPA311(Analog Subscriber Line Board Assembly) is offer the interface of between analog subscriber and TDX-100 exchange system. DSPA311 is belong ASI block, accommodate dial and MFC telephone subscriber of 32 channel, and voice signal designed for interface with TSW, and 2 and 4 wire loop impedance is 600 (ohm). DSPA311 is consist 4 channel daughter beard QSLM-10(Quad Subscriber Line Module-10) and perform BORSCHT and be possible A/U-law select and GAIN value control by data control of DSPA171(Device controller I). In this Paper, We described the function test program for the DSPA311 Board by using the HP3070CT combinational test system, and an unmanned automatic test system.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.1
• /
• pp.33-37
• /
• 2009

In this paper, a printed small Ultra-Wideband (UWB) antenna with directive radiation characteristics based on combination of electric-magnetic radiators is presented. The combinations of the electric and magnetic type antennas result in the directive radiation patterns for all observed UWB frequency band. Simple combination of dipole antenna and loop antenna is also presented to show that proper configuration of electric radiator and magnetic radiator can produces directive radiation characteristics. The target frequency is from 3.1 GHz to 10.6 GHz with size of $15\;mm{\times}31\;mm$. A proto-type of the combined antenna is simulated, fabricated and measured. Simulation and experimental results of input impedance and gain characteristics of the proposed antenna are presented. There are good agreements between the simulated and measured VSWR curves. Also, the results show the directive radiation characteristics with small antenna form factor over the target frequency range.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.4
• /
• pp.174-179
• /
• 2002

In this paper, the modified simulation algorithms of the Auto Transformer (AT) feeding electric train system were proposed. To obtain terminal voltage of train by using equivalent circuit or the AT feeding system, the iterative method is proposed for which determine the train voltages. The train voltages are iteratively calculated from the system voltage drop and line impedance. In the carte study, the proposed method is verified from actual operation data of the Kwa-Chon line. Also it is verified that the proposed method can be extent to the multi-train simulation tool. The terminal voltage of the multi-train can be calculated by using superposition principle and it is easily applied to the proposed method. Therefore, the proposed method can be a solution for the complexity of the circuit analysis in the existing methods.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.9
• /
• pp.1064-1072
• /
• 1999

The basic concepts, which are related to the PSS tuning conditions and performance conditions for the safe of determination of PSS gain and compensation of phasor lagging, are thoroughly investigated in this first part. The performance conditions, where the power system has the lowest inherent damping torque and PSS should provide maximum damping torque, are examined by analysing synchronizing torque and damping torque supplied by the voltage control loop at the oscillation frequency. PSS tuning conditions are also investigated by observing the phasor lagging and the gain, resulted from power system-generator-excitation system depending on operating conditions, such as generator active power, reactive power, transmission impedance and AVR gain. The basic concepts developed in this PartImake it possible to lay foundation for the discussion of PSS tuning in Part II.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.54 no.4
• /
• pp.163-170
• /
• 2005

This paper deals with an improved fault location algorithm with compensation ground capacitance through distributed parameter for a long parallel T/L. For the purpose of fault locating algorithm non-influenced by source impedance and fault resistance, the loop method was used in the system modeling analysis. This algorithm uses a positive and negative sequence of the fault current for high accuracy of fault locating calculation. Power system model of 160km and 300km long parallel T/L was simulated using EMTP software. To evaluate of the proposed algorithm, we used the several different cases 64 sampled data per cycle. The test results show that the proposed algorithm was minimized the error factor and speed of fault location estimation.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.145-147
• /
• 2002

In this paper, the improved fault locating method using distributed parameter which calculating the reduced voltage and current according to the ground capacitance in long transmission line was proposed. For the purpose of the fault locating algorithm non influenced source impedance, the loop method was used in the system modeling analysis. To enhance the fault locating, zero sequence of the fault current which is variable according to ground capacitance was not used but positive and negative sequence. System model was simulated using EMTP software. To verify the accuracy of proposed method, in different cases 64 sampled data per cycle was used and 160km and 300km long transmission line has fault resistance $0{\Omega}\;and\;100{\Omega}$ respectively was compared.

• ETRI Journal
• /
• v.31 no.1
• /
• pp.74-76
• /
• 2009

A new feeding method for the circular polarization (CP) dielectric resonator antenna (DRA) is proposed in this letter. Two orthogonal modes (${TE^x}_{{\delta}11}$, ${TE^y}_{1{\delta}1$) of the rectangular DRA are excited by a $90^{\circ}$ phase difference of the differential and common modes currents of the proposed feeding structure. To demonstrate the good CP performance of the proposed method, a right-hand CP DRA for a global positioning system was designed. The impedance bandwidth of the proposed antenna for $S_{11}$ < -10 dB and 3 dB axial ratio bandwidth are about 5.4% and 1.95% at 1.57 GHz, respectively.

• Smart Structures and Systems
• /
• v.11 no.2
• /
• pp.135-161
• /
• 2013

This work presents a test platform for the assessment and benchmarking of modern actuators which have been specifically developed for the new field and service robotics applications. This versatile platform has been designed for the comparative analysis of actuators of dissimilar technology and operating conditions. It combines a modular design to adapt to linear and rotational actuators of different sizes, shapes and functions, as well as those with different load capacities, power and displacement. This test platform emulates the kinematics of robotic joints while an adaptive antagonist-load actuator allows reproducing the variable dynamic loads that actuators used in real robotics applications will be subjected to. A data acquisition system is used for monitoring and analyzing test actuator performance. The test platform combines hardware and software in the loop to allow actuator performance characterization. The use of the proposed test platform is demonstrated through the characterization and benchmarking of three controllable impedance actuators recently being incorporated into modern robotics.