• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.396-401
• /
• 2003

Electrical impedance tomography(EIT) is a relatively new imaging modality in which the internal impedivity distribution is reconstructed based on the known sets of injected currents and measured voltages on the surface of the object. In this paper, an effective dynamic EIT imaging scheme is presented based on the projection filtering to estimate the unknown resistivity distribution. In particular, pre-integration (pre-grouping) technique is employed to stabilize the inverse algorithm. We carried out computer simulations with synthetic data to illustrate the reconstruction performance of the proposed algorithm.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.264-266
• /
• 2006

This paper presents a impedance model for the simulation of both static and dynamic characteristics of the electrodeless fulorescent lamp. A behavioral, PSpice compatible, model has been developed for the electrodeless fluorescent lamp. The model was tested at steady-state for different power levels, with an LCC modulated drive. and this model is established from some equations and measured electrical characteristics of EEFL. The validity of proposed lamp model is verified from the simulation and experimental results.

• International Journal of Automotive Technology
• /
• v.6 no.4
• /
• pp.391-402
• /
• 2005

Despite its superior braking performance to conventional vehicles on test tracks, the performance of the ABS-equipped car seems disappointing on real highway. The poor braking performance results from questionable design of the human-machine interface(HMI) of the brake system. Force-displacement relation at the brake pedal has a strong effect on the braking performance. Recently developed brake-by-wire (BBW) system may allow us to tailor the force feel at the brake pedal. This study aims at exploring analytical ways of designing human-machine interface of BBW system. In this paper, mathematical models of brake pedal feel for electro-hydraulic BBW (EH-BBW) system are developed, and the braking motion and the characteristics of the driver's leg action are modeled. Based on the dynamic characteristics of the brake pedal and the driver, two new HMI designs for EH-BBW system are proposed. In the designs, BBW system is modeled as a type of master-slave teleoperator. The effectiveness of the proposed designs is investigated using driving simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.1038-1043
• /
• 2002

The floating ring journal bearing is attraction for high-speed turbo machinery applications, including turbochargers and aircraft accessory equipment, because it is not only simple and easy to make and to replace in the field but also it seems to have adequate high speed stability characteristics. Therefore, an analysis method of dynamic properties of floating ring journal bearing is presented. The static equilibrium locus of inner film and outer film are calculated by using the impedance description. The equivalent stiffness and damping coefficients of floating ring journal bearing are composed by using the equilibrium of torque between inner film and outer film. Then, a stability analysis of turbocharger shaft system supported with floating ring journal bearing has been performed.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.9
• /
• pp.1-9
• /
• 1997

Novel class A CMOS second-generation current conveyors (CCII) using 0.6.mu.m n-well standard CMOS process for high-frequency current-mode signal processing were developed. The CCII consists of a regulated current-cell for the voltage input and a cascode current mirror for the current output. In this architecture, the two input stages are coupled by current mirrors to reduce the current input impedance. Measurements of the fabricated cCII show that the current input impedance is 308 .ohm. and the 3-dB cutoff frequency when used as a voltage amplifier extends beyond 10MHz. The linear dynamic ranges of voltage and current are from -0.5V to 1.5V and from -100.mu.A to +120.mu.A for supply voltage V$\_$DD/ = -V$\_$SS/=2.5V, respectively. The power dissipation is 2 mW and the active chip area is 0.2 * 0.2 [mm$\^$2/].

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.6
• /
• pp.48-55
• /
• 2004

Design for quite operation of fluid power system requires the understanding of noise and vibration characteristics of the system. This paper presents a dynamic response of design of hydraulic circuit. Experimental investigations on the attenuation of pressure ripple in automotive power steering hydraulic pipe line is examined. Also, a mathematical model of hydraulic pipe is p개posed to support a design of the hydraulic circuit. and the impedance characteristics of pressure ripple is analyzed. It is experimentally shown that power steering hydraulic pipe attenuates pressure ripple with high frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.1047-1051
• /
• 2004

Charge amplifier systems benefit from the very wide dynamic range of PE accelerometers by offering flexibility in adjusting the electrical output characteristics such as sensitivity and range. They are well suited for operation at high temperatures. Modern charge systems feature improved low noise operation, simplified digital controls, and dual mode operation for operation with charge or IEPE voltage mode sensors. high impedance circuitry is not well suited for operation in adverse field or factory environments. The resolution of a PE accelerometer may not be specified or known since noise is a system consideration determined by cable length and amplifier gain. IEPE accelerometrs operate from a constant current power source, provide a high-voltage, low-impedance, fixed mV/g output. They operate through long, ordinary, coaxial cable in adverse environments without degradation of signal quality. They have limited high temperature range. IEPE sensors are simple to operate. Both resolution and operating range are defined specifications. Cost perchannel is lower compared to PE systems since low-noise cable and charge amplifiers are not required.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1997.04a
• /
• pp.115-127
• /
• 1997

A study to evaluate the seismic response of $\frac{1}{2}$-scaled liquid storage tank constructed in Hualien, is performed. And this study is to identify the liquid-structure-soil interaction by observed earthquake data ans analyzed results. After the calculation of soil impedance for the test site by SASSI code, 3-dimensional seismic response analysis is performed by BEM-FEM-Impedance Method with the consideration of liquid-structure-soil interaction when the tank is excited by real earthquake. The observed acceleration and hydrodynamic pressure are compared with the numerical results. This comparisons show good agreement in predominant frequency and maximum hydrodynamic pressure. And the free surface sloshing motion due to earthquake loadings is computed in time domain.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.289-291
• /
• 2008

태양전지에 관한 많은 모델이 제안되어 왔으나 대부분은 특정 일사량에서 측정된 태양전지의 I-V 특성커브를 기준으로 보간법을 사용하여 운전점을 구하는 모델링 방식을 사용하고 있으며, 태양전지의 동특성 모델에 관한 연구는 매우 드물다. 효율적인 에너지 변환을 위한 고성능 전력변환기의 설계를 위해서는 태양전지의 정특성 및 동특성에 관한 정확한 정보가 요구된다. 태양전지의 정특성은 제조사에 의해 일반적으로 측정되어 공개되므로 용이하게 이해될 수 있으나 동특성은 그렇지 못하다. 본 논문에서는 임피던스 분광법(Impedance Spectroscopy)을 이용하여 태양전지 모듈의 동특성 모델을 개발하고, 개발된 모델의 유용함과 정밀함을 실험을 통해 검증 하였다. 개발된 동특성 모델은 정밀한 태양전지 시뮬레이션과 새로운 MPPT 알고리즘 개발에 이용될 수 있을 것으로 기대된다.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.295-297
• /
• 2008

슈퍼커패시터는 전력밀도가 높고 사이클 수명이 긴 무공해 소자로 신재생에너지원이나 배터리의 동특성 보상 및 수명연장을 목적으로 그 사용이 증대되고 있다. 본 논문에서는 이러한 슈퍼커패시터의 정확한 동특성 모델을 임피던스 분광법(Impedance Spectroscopy)을 이용하여 개발하고, 개발된 모델의 유용함을 시뮬레이션을 통해 검증하였다. 주파수영역에서 개발된 모델은 시간영역으로 등가 변환되어 Matlab/Simulink를 이용하여 시뮬레이션 되었고, 실험결과와 비교되었다. 다수의 제조사에서 제작된 비슷한 용량의 슈퍼커패시터들의 임피던스 모델을 개발하고 전압에 따른 커패시턴스의 변화를 비교하고 분석하였다. 또한, 상용 장비로는 모델링이 불가능한 고압 슈퍼커패시터 모듈의 모델링을 수행할 수 있는 새로운 방법을 제안하고, 제안된 방법에 의해 개발된 모델의 유용함을 실험을 통해 검증하였다.