• 전기학회논문지
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• 제58권7호
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• pp.1411-1417
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• 2009

In this paper, we consider the design of $H_{\infty}$ control of linear discrete-time systems having no mathematical model. The basic approach is to use Q-learning which is a reinforcement learning method based on actor-critic structure. The model-free control design is to use not the mathematical model of the system but the informations on states and inputs. As a result, the derived iterative algorithm is expressed as linear matrix inequalities(LMI) of measured data from system states and inputs. It is shown that, for a sufficiently rich enough disturbance, this algorithm converges to the standard $H_{\infty}$ control solution obtained using the exact system model. A simple numerical example is given to show the usefulness of our result on practical application.

• The Journal of Korean Physical Therapy
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• 제15권3호
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• pp.265-276
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• 2003

This study was to investigate the dffects of a color reversal visual perceptual training program on spastic cerebral palsied children's figure-ground discrimination disabilities and to investigate the difference between the control group and experimental group. Subjects of the study were composed of children with spastic cerebral palsy whose age varied from five to seven years old, whose I.Q. was over 70 and whose P.Q. was over 70. Implication of this study can be summarized as follows; First, Perceptual training and speech training programs should be emphasized to improve the preparative ability of spastic cerebral palsied children. Problems of perception cerebral palsied children are concerned with figure-ground discrimination disability. Second, Though it was demonstrated that color reversal visual perceptual training program can be effective through the prestudies and this study, more researches should be made to apply this kind of theory in real education environments. More interest in different color forms for training of cerebral palsied children should be taken. Third, Reprecations of the study should be considered with modified group identities(age, I.Q., P.Q.).

• 성인간호학회지
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• 제17권2호
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• pp.177-187
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• 2005

Purpose: The purpose of the study was to investigate the meaning of the life of middle-aged women. Method: The research method employed Q-methodology. Thirty-one participants rated 30 selected Q-statements on a scale of 1~7. The collected data were analyzed using PC-QUNAL software. Result: Principal component analysis identified 4 types of the meaning of the life of middle-aged women. The categories were labeled 'May I help you?', 'Alone', 'Who am I ?', 'No regret'. Conclusion: We have found meaning of life of middle-aged women through this research. The study result could be data to perform effective nursing intervention for positive life of middle-aged women.

• 한국자기학회지
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• 제10권1호
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• pp.30-36
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• 2000

Q switch mode 혹은 Fixed Q mode Nd-YAG 레이저 어블레이션법으로 (100)Si 기판위에 SmCo 박막을 증착하였다. 증착시 Sm$_{100-x}$Co$_{x}$ (73$\leq$x$\leq$93) 조성의 타겟을 사용하였고, 기판온도는 600~$700^{\circ}C$ 변화시켰으며 각 mode 에너지를 조절하였다. Q switching mode로 증착된 박막의 4$\pi$Ms, $_{i}$H$_{c}$ 및 4$\pi$M$_{r}$/4$\pi$M$_{s}$는 각각 5.2~7.7 kG, 190~250 Oe, 0.4~O.74이었다. 반면, Fixed Q mode로 얻어진 박막의 $_{i}$H$_{c}$, 4$\pi$M$_{r}$/4$\pi$M$_{s}$는 각각 430~6290 Oe, 0.32~0.91로 훨씬 양호한 경자기 특성이 나타났다. 후자의 자기특성은 박막에 존재하는 입자(droplet)내 SmCo$_{5}$ 와 Sm$_2$Co$_{17}$상의 생성에 의한 것으로 판단된다. 입자의 존재로 인한 박막표면의 거칠기는 향후 연구에서 해결되어야 할 문제점으로 확인되었다.문제점으로 확인되었다.었다.

• Journal of Electrical Engineering and Technology
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• 제7권4호
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• pp.570-575
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• 2012

In a wireless communication RF transmitter, the output of a quadrature modulator (QM) is distorted by not only the linear imperfection features such as in/quadrature-phase (I/Q) input gain imbalance, local phase imbalance, and local gain imbalance but also the nonlinear imperfection features such as direct current (DC) offset and mixer nonlinearity related to in-band spurious signal. In this paper, we propose the unified QM model to analyze the combined effects of the linear and nonlinear imperfection features on the performance of the QM. The unified QM model consists of two identical nonlinear systems and modified I/Q inputs based on the two-port nonlinear mixer model. The unified QM model shows that the output signals can be expressed by mixer circuit parameters such as intercept point and gain as well as the imperfection features. The proposed approach is validated by not only simulation but also measurement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.372-375
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• 2001

본 논문에서는 고속데이터 전송을 위한 CDMA 모뎀를 구현하였다. 데이터율 1Mbps의 트래픽 5채널에 직교부호를 곱하여 채널을 구분한 후 하나의 채널로 처리하였다. I,Q로 입력된 신호는 복소 곱셈기에서 칩 레이트 8Mcps로 OCQPSK(또는 HPSK) 변조하였다. 복조기는 I,Q의 신호를 역확산한 후 직교부호를 다시 곱하여 각 채널의 데이터를 분리한다. 변복조기의 구현은 클럭 속도 167MHz의 부동 소수점형 프로세서인 TI사의 TMS320C6701 DSP(Digital Signal Processor)를 사용하었고, long code 및 I,Q 채널 PN 코드는 IMT-2000 동기방식과 비동기방식의 규격에 정의된 2가지의 PN코드 발생기를 모두 구현하였다.

• 전기전자학회논문지
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• 제18권4호
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• pp.502-508
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• 2014

This paper has reviewed the performances of various AGCs which can be adopted in IEEE802.11p modems. IEEE802.11p, a high speed mobile communication standard for vehicles, requires high performance signal detector since the channel impulse responses are varied rapidly in time. In order to select the optimal signal detector, we simulated the performances of three detection methods. One is using RSSI signal, the other is using RSSI signal and I/Q signal, and the third is using I/Q signal through the Monte Carlo simulation. We evaluated the performances of the algorithms using our own system based on MAX 2829 transceiver(MAXIM $Integrated^{TM}$) in a real vehicular environment. As a result, the experiment using Fully I/Q signal derives the most excellent performance with the lowest minimum receiver sensitivity, packet error rate (PER) and false alarm rate (FAR).

• International Journal of Precision Engineering and Manufacturing
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• 제6권2호
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• pp.34-39
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• 2005

The precision stage is an essential device for optic fiber assembly systems, micro machines and semiconductor equipments. A new piezoelectric inchworm type actuator is proposed to implement an actuator-integrated long-stroke linear stage. An in-and-quadrature phase (I/Q) heterodyne interferometer is developed as a feedback sensor of a servo system, and a synchronized counting method is proposed. The proposed measurement system can measure the accurate position of fast moving object with robustness to external sensing noise from actuator vibration. The developed servo stage will be applied to optic fiber device assembly system.

• 스마트미디어저널
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• 제7권2호
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• pp.9-14
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• 2018

The k-ary n-cube $Q^k_n$ is widely used in the design and implementation of parallel and distributed processing architectures. It consists of $k^n$ identical nodes, each node having degree 2n is connected through bidirectional, point-to-point communication channels to different neighbors. On $Q^k_n$ we would like to transmit packets from a source node to 2n destination nodes simultaneously along paths on this network, the $i^{th}$ packet will be transmitted along the $i^{th}$ path, where $0{\leq}i{\leq}2n-1$. In order for all packets to arrive at a destination node quickly and securely, we present an $O(n^3)$ routing algorithm on $Q^k_n$ for generating a set of one-to-many node-disjoint and nearly shortest paths, where each path is either shortest or nearly shortest and the total length of these paths is nearly minimum since the path is mainly determined by employing the Hungarian method.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.570-572
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• 2008

The modulation quality of the I/Q modulator in a wireless transmitter usually affects system performance and it mostly depends on both a nonlinearity and a distortion, from the third order intermodulation($IM_3$) signal and the error components such as an input amplitude error and a local phase error, respectively. This paper focused on how much the Single Sideband Ratio(SSR), which indicates the signal distortion, changes according to the variation of the error components. Consequently, since a desired signal, side band signal at the I/Q modulator output are also represented with those power series coefficients and the error components, the effects of the error components on SSR to meet the EVM specification of the WPAN can be clearly analyzed.