• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.305-308
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• 1999

In this paper, a transimpedance optical receiver based on PIN/P-HEMT with cascoded input stage and inductor peaking technique was designed for several giga bits optical communication. Analysis of the receiver shows that cascoded input stage with inductor peaking increase bandwidth without sacrificing low frequence gain. The receiver achieved a low noise characteristic and maximally flat frequence response. It is shown that the 3-dB bandwidth of the designed receiver is 8.3 ㎓ and input equivalent noise current is as low as 16pA/√Hz to 10㎓.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.613-617
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• 2002

The ceramic filters were developed using technology similar to that of quartz crystal and electromechanical filter. However, the key to this development involved the theoretical analysis of vibration modes and material improvements of piezoelectric ceramics. The primary application of ceramic filters has been for consumer-market use. Accordingly, a major emhpasis has involved mass production technology, leading to low-priced devices. A typical ceramic filter includes monolithic resonators and capacitors packaged in unique configurations. Nakazawa developed a double-mode resonator as two acoustically coupled single resonators. And he developed 10.7MHz crystal filters using multi-energy trapping mode of thickness shear vibration. He succeeded in realizing a two-pole band pass filter response without external inductance by splitting a dot electrode to creat coupled symmetric and antisymmetric vibration modes. Accordingly, the simulation for ceramic filter were important. So that, this paper were investigated the pass frequency of filter on the electrode length and thickness of ceramic.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.417-419
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• 1998

The ICD(Individual-Channel-Design) is a multivariable control design method based on the classical frequence response, in which the channel decomposition and the loop shaping on frequence domain are introduced. However, in this manner, it is difficult to satisfy time domain specifications such as overshoot, rise time, settling time. To solve the problem, we propose a new design method using CDM(Coefficient Diagram Method). And a new feedforward compensator is introduced for reducing interconnections.

• 조명전기설비학회논문지
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• 제27권7호
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• pp.95-100
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• 2013

In this paper, we propose an active controller for high-speed pantograph in order to improve the transient response. Electrical power is delivered from a catenary to the train via a pantograph and thus it is very important to regulate the contact force between catenary and pantograph. By regarding the catenary displacement as an unknown disturbance input and analyzing the frequency response from the disturbance to contract force. we present an active controller that utilizes the lead compensator and resonant controller. It is shown by the computer simulation that the substantial improvement in transient response can be achieved by the proposed controller.

• 한국기계가공학회지
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• 제2권2호
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• pp.75-83
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• 2003

Recently, the machine tools have been needed for high speed and accuracy to increase productivity. The most Important thing to get a more stabilized machine is to know the frequency response which has an effect on manufacture a lot. This problem should be considered seriously by many researchers. There are many application programs about FEM but Just using FEM program to get information of the object is not enough to put our confidence in the stability of the machine tool design. Therefore, the purpose of this research is to make a study for proving one of the ways to design to produce stabilized a machine more efficiently by comparing FRT method and FEM. At these two tests, we can learn about the frequency response area causing resonance and we can reconfirm the result to trust.

• 한국조리학회지
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• 제11권3호
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• pp.40-55
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• 2005

The purpose of this study was to understand the effect of customers' repurchase intention, extract important factors, systematically analyze them and suggest the direction of bakery industry through studying the customers' satisfaction with bakeries. The researcher modified the questionnaire developed by Park, CH(1998), Lee, JH(2000), Yoon, YC(2000), and Kim SE(2002). In order to assess the level of customers' satisfaction with bakeries, a five point Likert scale was used. The used statistical methods for the data analysis were frequency analysis, reliability analysis, t-test factor analysis, ANOVA, multiple regression analysis. For all analyses of the research question, an alpha level of.05 was used. The major findings obtained from this study were as fellows. First on the factors of reliability and service ability, there was a high difference between males and females, and singles and the married. Second, on the factors of accessibility using convenience, service ability, and service response, there was a high difference among using frequence. Third, on the reliability factors, there was a high difference among average using amount per month. Forth, on the factors of accessibility using convenience, and service response, there was a high difference among types of customers' residing styles. Fifth, on the factors of income level, there was statistically no difference. Lastly, on the factors of accessibility using convenience, tangibleness, and service response, these factors significantly influenced customers' repurchase intention.

• 융합신호처리학회논문지
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• 제1권1호
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• pp.15-22
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• 2000

선형 자귀회귀(AR) 모델을 근거로한 심박변동의 파워 스펙트럼 해석은 비침습적으로 자율신경의 반응을 정량화 하는데 폭넓게 사용된다. 본 연구는 짧은 데이터 저장(2분 미만)의 심전도와 맥파 신호의 심박변동에 대한 파워스펙트럼밀도을 추정한다 심박변동의 시계열은 정상인을 대상으로 검출한 심전도와 맥파신호의 특징점 사이의 시간간격(RRI, PPI)으로부터 구하였다. 발생된 시계열은 다항식 보간법에 의해 AR모델에 적합하게 새로운 시계열로 재구성하였다 AR모델에 의한 파워스펙트럼 밀도는 Burg 알고리즘을 사용하여 계산하였다 AR 모델을 적용한 단 구간의 심전도와 맥파의 심박변동에 대한 파워스펙트럼밀도는 저주파수와 고주파수 영역에서 매끄러운 스펙트럼 파워를 나타내고 있다. 또한 통일한 피험자의 심전도와 맥파의 파워스펙트럼밀도를 비교한 결과 유사한 모양을 나타내었다.

• Journal of Power Electronics
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• 제12권1호
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• pp.67-74
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• 2012

According to electrical output up rating of a permanent magnet motor and request to operate for a large variable speed range, resonance between structural natural vibration and electromagnetic force inside the motor can take place and make noise. This paper describes the mechanism of a resonance between them and noise lowering procedure by frequency shift when they are applied to the reluctance torque largely employed new motor named Permanent magnet Reluctance Motor (PRM).

• 한국진공학회지
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• 제4권4호
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• pp.413-416
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• 1995

고주파 마그네트론 스펏터링법을 이용하여 ZnO막을 제조하고 유리기판 위에 ZnO-SAW필터를 제작하였다. ZnO막의 제조 조건은 고주파 전력 150W, 기판온도 $200^{\circ}C$, 분위기압 5mTorr 및 O2/(Ar+O2)비 50%였다. 한편 IDT(Inter-digital transducer)전극은 전극 폭을 2.56mm, 전극 거리를 2,936mm, λ/8폭을 $8mu$m로 설계하였다. 제작된 ZnO-SAW필터의 주파수 응답을 측정하기 위해 소자는 mount(TO8)에 고정시켰다. ZnO SAW필터의 통과 대역(3 dB대역폭)은 345.2~44.8 MHz로 9.6MHz의 대역 폭을 나타내었으며 중심주 파수는 40 MHz를 나타내었다. 또한 삽입 손실은 39 dB, 통과 대역에서의 리플(ripple)은 $\pm$ 0.8 dB 및 rejection은 17 dB를 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.475-478
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• 1999

In this paper, we propose the robust performance design of multivariable systems within the framework of Quantitative Feedback Theory(QFT) using ICD. The ICD(Individual Channel Design) is a multivariable control method based on the classical frequence response. It is considered to apply feedforward controller for compensating the effect of interconnection between channels. Performance of the proposed method are demonstrated by simulations in appling gas turbine model.