• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.190-193
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• 2013

스마트폰이 출시하기 전 과거 핸드폰의 음악 재생력은 아주 한정적이었기 때문에 MP3 플레이어를 필요로 했으나 스마트폰이 등장하면서 멀티미디어 재생은 필수적인 기능이 되었으며, MP3의 모든 기능이 작동하게 되었다. 그리고 하나의 기기에서 음악 및 멀티미디어 재생의 모든 것이 이루어지기 때문에 편리하지만 스마트폰의 음질 부분에 있어서의 논란은 끊이지 않았다. 본 논문은 스마트폰이 가진 음악 재생기능 중 EQ(Equalizer)를 Right Mark Audio Analyzer 프로그램을 통하여 EQ(Equalizer) 밸런스 조절을 통한 하이 피델리티(High Fidelity)에 가까운 사운드의 재생에 관하여 알아본다.

• 전기학회논문지P
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• 제66권4호
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• pp.182-187
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• 2017

Synchronous generators have been significantly applied in large-scale power plants and its monitoring systems are additionally established to sequentially observe states and outputs. We develop a computer based monitoring device for three-phase synchronous power generators in this paper. First, a test-bed of such generator system is created and then a interface board is constructed to transfer electric signals including the output voltage and the current from generators into a computer system via a data acquisition device. Its RMS(root-mean-square) values are continuously shown on a screen of computer systems and its time-histories graphs are additionally illustrated under a graphic user interface(GUI) mode. Lastly, we carry out real-time experiments using the generator system with the monitoring device to demonstrate its reliability and superiority by comparing results of a generic power analyzer which is well-used in measuring various power systems practically.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.54-55
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• 2011

To transfer the power wirelessly, the inverter converted DC power to a high frequency MHz-grade AC power. And the ECR devices for wirelessly transmitting the power are required. In this paper, the spiral-type ECR device and the high frequency inverter were designed. The operating frequency is approximately 1.2MHz. In addition, using a vector network analyzer, the 1.2MHz operating characteristics of the ECR device for wireless power transfer module are analyzed. It is performed and reviewed on validity of wireless power transfer technologies through experiments.

• 펄프종이기술
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• 제32권3호
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• pp.10-17
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• 2000

The MDDA(Modified Dynamic Drainage Analyzer) was developed to evaluate the drainage at hydrofoil table roll and low vacuum devices on fourdrinier paper machine MB-former. Comparison of the results was obtained using a computer simulation system based on Taylor's equation and filtration equation and by measuring the consistency profile in a paper machine presented an agreement within 10.7% This device can evaluate the dewatering pro-file on wire for various stock properties adjust dewatering devices on fourdrinier paper machine and control the dosage of retention aids for improving paper structural properties and runnability of papermachine.

• 한국세라믹학회지
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• 제46권1호
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• pp.41-46
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• 2009

The rheological properties of highly concentrated Ag nano sol depending on particle size were studied. The Ag nano sol was prepared by reducing the Ag ion in aqueous solution. The size of Ag nano particle was controlled by two steps of nucleation and growth, and the thickness of adsorption layer was varied by molecular weight of polyelectrolytes. The polyelectrolytes acted as not only ionic complex agent in ionic state and but also dispersant after formation of Ag nano sol. The effective volume was controlled by combination of varying the molecular weight of polyelectrolytes and the size Ag nano sol. The particle size and the viscosity of nano sol were characterized by particle size analyzer, HR-TEM and cone & plate viscometer. It was found that the 10 nm and 40 nm-sized Ag nano sols were prepared by controlling the nucleation and growth steps, respectively. Finally, we could prepare highly concentrated Ag nano sol over 50 wt%.

• 한국통신학회논문지
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• 제7권4호
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• pp.156-160
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• 1982

A Comb Filter(C.F.) is constucted with a N-stages one-dimensional B.B.D.(Bucket-Brigade Device) delay line. One channel of the B.P.F. (Band Pass Filter) Bank is experimented, which includes a R.F.(Recursie Filter) using S/H circuits cascaded to the C.F. This algorithm of the C.F.B.(Comb Filter Bank) becomes the parallel spectrum analyzer circuit. The algorithm has less number of multiplication than that of FFT and improves the SNR.

• 전기학회논문지
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• 제56권5호
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• pp.905-909
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• 2007

Crystalline and micro-structural characteristics of ZnO thin films which were deposited on p-Si(100) with cooling naturally down of pre-heated substrate during RF magnetron sputter deposition, were investigated by XRD and SEM in this paper. The film which was prepared on the substrate which was pre-heated to $400^{\circ}C$ before deposition and then cooled naturally down during deposition, showed the most outstanding c-axis preferred orientation. The ZnO thin film having the best crystalline result were applied to SMR type FBAR device and resonance properties of the device were investigated by network analyzer. It showed that resonance frequency was 2.05 GHz, return loss was -30.64 dB, quality factor was 3169 and electromechanical coupling factor was 0.4 %. This deposition method would be very useful for application of surface acoustic wave filter or film bulk acoustic wave resonator.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2434-2440
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• 2018

A new type of piezoelectric micromachined ultrasonic transducer (pMUT) with high resonant frequency was developed by using a thin lead zirconate titanate (PZT) as an insulation layer on a floating $10{\mu}m$ silicon membrane. The PZT insulation layer facilitated acoustic impedance matching at active pMUT, leading to a high performance in the acoustic conversion property compared with the transducer using $SiO_2$ insulation layer. The fabricated ultrasonic devices were wirelessly measured by connecting two identical acoustic transducers to two separate ports in a single network analyzer simultaneously. The acoustic wave emitted from a transducer induced a $3.16{\mu}W$ on the other side of the transducer at a distance of 2 cm. The transducer performances in terms of device diameters, PZT thickness, annealings, and different DC polings, etc. were investigated. COMSOL simulation was also performed to predict the device performances prior to fabrication. Based on the COMSOL simulation, the device was fabricated and the results were compared.

• International journal of advanced smart convergence
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• 제11권4호
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• pp.57-67
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• 2022

The demand for personal training (PT), through which high exercise effects can be achieved within short-term, has recently increased. PT can achieve an exercise amount improvement effect, only if accurate postures are maintained upon performing PT, and exercise with inaccurate postures can cause injuries. However, research is insufficient on exercise amount comparisons and judging exercise accuracy on PT. This study proposes an exercise accuracy measurement algorithm and compares differences in exercise amounts according to exercise postures through experiments using a respiratory gas analyzer. The exercise accuracy measurement algorithm acquires Euler anglesfrom major body parts operated upon exercise through a motion device, based on which the joint angles are calculated. By comparing the calculated joint angles with each reference angle in each exercise step, the status of exercise accuracy is judged. The calculated results of exercise accuracy on squats, lunges, and push-ups showed 0.02% difference in comparison with actually measured results through a goniometer. As a result of the exercise amount comparison experiment according to accurate posture through a respiratory gas analyzer, the exercise amount was higher by 45.19% on average in accurate postures. Through this, it was confirmed that maintaining accurate postures contributes to exercise amount improvement.

• 한국정밀공학회지
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• 제30권1호
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• pp.128-133
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• 2013

Si Nanowire (Si-NW) arrays were fabricated by top-down method. A relatively simple method is suggested to fabricate suspended silicon nanowire arrays. This method allows for the production of suspended silicon nanowire arrays using anisotropic wet etching and conventional MEMS method of SOI (Silicon-On-Insulator) wafer. The dimensions of the fabricated nanowire arrays with the proposed method were evaluated and their effects on the Field Effect Transistor (FET) characteristics were discussed. Current-voltage (I-V) characteristics of the device with nanowire arrays were measured using a probe station and a semiconductor analyzer. The electrical properties of the device were characterized through leakage current, dielectric property, and threshold voltage. The results implied that the electrical characteristics of the fabricated device show the potential of being ion-selective field effect transistors (ISFETs) sensors.