• Transactions on Electrical and Electronic Materials
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• 제9권3호
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• pp.128-133
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• 2008

In this paper, in order to analyze property of frequency response in microphone using optical sensor, acousto-optic sensor system has been implemented. The capacitance microphone and fiber-optic transmission path type fiber-optic microphone (FOM) have weaknesses in directivity, size, weight, and price. However suggested optical microphone can be constituted by cheap devices, so it has many benefits like small size, light weight, high directivity, etc. Head part of optical microphone which is suggested in this paper is movable back and forth by sound pressure with the attached reflection plate. Operating point has also been determined by measuring the response characteristics. The choosing the point, which has maximum linearity and sensitivity has changing the distance between optical head and vibrating plate. We measured the output of the O/E transformed signal of the optical microphone while frequency of sound signal is changed using sound measurement /analysis program, "Smaart Live" and "USBPre", which are based on PC, and compared the result from an existing capacitance microphone. The measured optical microphone showed almost similar output characteristics as those of the compared condenser microphone, and its bandwidth performance was about 4 kHz at up to 3 dB.

• 전기전자학회논문지
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• 제20권3호
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• pp.307-309
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• 2016

본 논문에서는 기존 LDO 레귤레이터에서 간단한 피드백 구조를 이용하여 과도응답을 향상시킨 LDO 레귤레이터를 제안한다. 이 제안된 회로는 기존 LDO 레귤레이터에서 나타나는 오버슈트의 응답시간을 감소시켜 더 안정적인 동작을 하도록 하는 피드백 구조를 갖는다. 제안 된 피드백 구조는 큰 면적의 변화 없이 기존 LDO 레귤레이터와 같은 동작을 하며, 출력에서의 노이즈를 갖는 LDO 레귤레이터의 단점을 보완한다. 설계한 회로는 동부 하이텍의 0.18um CMOS 공정을 이용하였다.

• 조명전기설비학회논문지
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• 제18권6호
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• pp.84-90
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• 2004

제어계에서 제어성능을 개선시키기 위해서 많은 제어기법들이 제안되어왔다. 궤환제어계에서 일반적으로 제어기의 출력이 제어대상의 입력으로 사용된다. 그러나 불필요한 잡음이 제어기의 출력에 포함된다. 그러므로 이러한 잡음을 제거하고 계의 응답특성을 개선시키기 위해서 전치보상기를 사용할 필요가 있다. 본 논문에서는 모델추종제어를 위한 전치보상기의 설계법을 I-PD 제어계에서 제안하였다. 제안한 전치보상기를 신경망으로 구현하였고, 계의 응답특성이 어떤 조건하에서 변할 때 원하는 응답이 되도록 전치보상기의 이득이 자동적으로 조정되도록 하였다.

• Wind and Structures
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• 제16권2호
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• pp.157-178
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• 2013

Output-only modal parameter identification is based on the assumption that external forces on a linear structure are white noise. However, harmonic excitations are also often present in real structural vibrations. In particular, it has been realized that the use of forced acceleration responses without knowledge of external forces can pose a problem in the modal parameter identification, because an external force is imparted to its impulse acceleration response function. This paper provides a three-stage identification procedure as a solution to the problem of harmonic and white noise excitations in the acceleration responses of a linear dynamic system. This procedure combines the uses of the mode indicator function, the complex mode indication function, the enhanced frequency response function, an iterative rational fraction polynomial method and mode shape inspection for the correlation-related functions of the force-embedded acceleration responses. The procedure is verified via numerical simulation of a five-floor shear building and a two-dimensional frame and also applied to ambient vibration data of a large-span roof structure. Results show that the modal parameters of these dynamic systems can be satisfactorily identified under the requirement of wide separation between vibration modes and harmonic excitations.

• Smart Structures and Systems
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• 제31권2호
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• pp.141-154
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• 2023

After an earthquake, information regarding potential damage to buildings close to the epicenter is very important during the initial emergency response. This study proposes the use of crowdsourced measured acceleration response data collected from smartphones located within buildings to perform system identification of building structures during earthquake excitations, and the feasibility of the proposed approach is studied. The principal advantage of using crowdsourced smartphone data is the potential to determine the condition of millions of buildings without incurring hardware, installation, and long-term maintenance costs. This study's goal is to assess the feasibility of identifying the lowest fundamental natural frequencies of buildings without knowing the orientations and precise locations of the crowds' smartphones in advance. Both input-output and output-only identification methods are used to identify the lowest fundamental natural frequencies of numerical finite element models of a real building structure. The effects of time synchronization and the orientation alignment between nearby smartphones on the identification results are discussed, and the proposed approach's performance is verified using large-scale shake table tests of a scaled steel building. The presented results illustrate the potential of using crowdsourced smartphone data with the proposed approach to identify the lowest fundamental natural frequencies of building structures, information that should be valuable in making emergency response decisions.

• 대한전기학회논문지
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• 제36권9호
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• pp.685-690
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• 1987

Adaptive design of IIR digiral filters using equation error method has been studied. In this paper, a design technique of IIR digital filters using output error method with adaptive compensator is presented. In computer simulation results, it is shown that flat response characteristic in pass-band, below-40[dB] attenuation characteristic in stop-band, sharf cut-off characteristic in transition-band, and phase characteristic is linearin pass-band.

• 대한전자공학회논문지
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• 제26권11호
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• pp.1728-1735
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• 1989

A design procedure for microstrip bandpass filters using step impedance resonators (SIR's) and tapped input/output to a conventional parallel coupled line bandpass filter is presented. The filter configuration consisting of both half-wavelength and SIR's suppreses to spurious resonance response near the second harmonics, while tapping techniques offer benefit in situations where the impractical. The measured frequency responses of the designed filter are in close agreement with the computed responses.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.176.5-176
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• 2001

This paper presents a fuzzy dynamic output feedback controller design method for Parallel Distributed Compensation (PDC)-type Takagi-Sugeno (T-S) model based fuzzy dynamic system with H$\infty$ performance and additional constraints on the closed pole placement. Design condition for these controller is obtained in terms of the linear matrix inequalities (LMIs). The proposed fuzzy controller satisfies the disturbance rejection performance and the desired transient response. The design method is verified by this method for an inverted pendulum with a cart using the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.576-579
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• 1986

In this paper, a design method of an optimal output PIM(Proportional-Integral-Measurable) controller is presented so that the closed-loop output response of the switching regulator closely match to that of ideal model system satisfying the time domain specifications. The computer simulation for a design example is given to show the usefulness of the proposed technique.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.310-313
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• 2005

In this paper, four quadrant CBPS(Compact Bipolar Power Supply) which development and study using universal PWM controller. The CBPS has 24V DC-link voltage, +/-5A output current, 50kHz switching frequency and 30Hz full load bandwidth using FET device. Proposed system has two independent PWM controllers for each full-bridge switch leg drive and PI control loops for current regulations. It is shown experimental results that good step response of the current output.