• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.275-278
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• 2005

본 논문에서는 입력 필터의 영향을 받는 스위칭 전력변환기의 이론적인 해석 과정을 나타내었다. Middle-brook의 extra element theorem을 이용하여 이론적으로 입력 필터 상호 작용을 해석하였으며, 컴퓨터 시뮬레이션을 통해 확인하였다. 또한 전압 제어 및 전류 제어방식 승압형 변환기를 제작하여 이를 검증하였다.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2045-2056
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• 2016

The input impedances of pulse width modulated (PWM) dc-to-dc converters, which dictate the outcomes of the dynamic interaction between dc-to-dc converters and their source subsystem, are analyzed in a general and unified manner. The input impedances of three basic PWM dc-to-dc converters are derived with both voltage mode control and current mode control. This paper presents the analytical expressions of the 24 input impedances of three basic PWM dc-to-dc converters with the two different control schemes in a factorized time-constant form. It also provides a comprehensive reference for future dynamic interaction analyses requiring knowledge of the converters' input impedances. The theoretical predictions of the paper are all supported by measurements on prototype dc-to-dc converters. The use of the presented results is demonstrated via a practical application example, which analyzes the small-signal dynamics of an input-filter coupled current-mode controlled buck converter. This elucidates the theoretical background for the previously-reported eccentric behavior of the converter.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.13-16
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• 2002

This paper proposes a method to track hand gesture and to recognize the gesture pattern using Kalman filter and continuous dynamic programming (CDP). The positions of hands are predicted by Kalman filter, and corresponding pixels to the hands are extracted by skin color filter. The center of gravity of the hands is the same as the input pattern vector. The input gesture is then recognized by matching with the reference gesture patterns using CDP. From experimental results to recognize circle shape gesture and intention gestures such as “Come on” and “Bye-bye”, we show the proposed method is feasible to the hand gesture-based human -computer interaction.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.576-581
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• 1997

DC-DC converter with chopper is seen to have problems, such as, loop instability and degradation of transient response, due to the interaction between input filter and switching regulator. In this paper, the switching regulator consisting of input filter and double chopper is analyzed, and the state space model at continuous current mode and the transfer function between duty ratio of switching pulse and output voltage are derived. The controller in this paper is designed as feedforward(P) and feedback(PI) control scheme to minimize the variation of output voltage, and computer simulation results are presented to show the performance of the proposed controller.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.321-327
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• 2018

DC microgrid system composed of multiple converters has a tendency to make the system unstable due to the interaction of converters. To solve this problem, in this paper, the interaction between cascaded converters with LC input filter is analyzed with impedance modeling using g-parameter. The input impedance and the output impedance of the system can be obtained through this technique. The stability of the system can be determined by applying Middlebrook's stability criterion to the impedance. Virtual impedance is added to the controller to enhance stability. The validity of the analysis is verified by the result of several simulations and experiments.

• Journal of Biomedical Engineering Research
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• v.35 no.2
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• pp.14-18
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• 2014

This study is about e-Book program based on human-computer interaction(HCI) system for physically handicapped person. By acquiring background knowledge of HCI, we know that if we use vision-based interface we can replace current computer input devices by extracting any characteristic point and tracing it. We decided betweeneyes as a characteristic point by analyzing facial input image using webcam. But because of three-dimensional structure of glasses, the person who is wearing glasses wasn't suitable for tracing between-eyes. So we changed characteristic point to the bridge of the nose after detecting between-eyes. By using this technique, we could trace rotation of head in real-time regardless of glasses. To test this program's usefulness, we conducted an experiment to analyze the test result on actual application. Consequently, we got 96.5% rate of success for controlling e-Book under proper condition by analyzing the test result of 20 subjects.

• Science of Emotion and Sensibility
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• v.20 no.2
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• pp.127-136
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• 2017

Attentional blink is observed in an identification task of multiple targets during rapid serial visual presentation (RSVP) where performance for the second target (T2) that follows within 500ms of the first (T1) shows systematic decrease although that for T1 remains highly accurate. Theories accounting for attentional blink can be classified into two broad categories of resource depletion model and disruption of input filter model. Meanwhile, visual attention capacity shows hemifield independence between left and right visual fields, and many studies reported bilateral advantage in a range of visual working memory tasks. The current research tested two major theories of attentional blink using bilateral independence of attentional capacity. To this end, we conducted two experiments where two RSVPs were presented in either bilateral or unilateral visual fields. Experiment 1 presented two RSVPs which contained both T1 and T2 in either bilateral or unilateral visual fields and tested interaction between attentional blink and bilateral advantage. Experiment 2 removed T1 in one of the two RSVPs to test whether attentional blink obtains when identification of T1 and T2 utilize independent sources of attention across two visual fields. The results showed that subjects were more accurate when two RSVPs were presented in bilateral visual fields (i.e., bilateral advantage) although there was no interaction between attentional blink and bilateral advantage (Experiment 1). In addition, attentional blink for T2 was observed in a T1-absent RSVP even when two RSVPs were presented in bilateral visual fields (Experiment 2). These results support disruption of input filter model rather than resource depletion model.

• Journal of Advanced Navigation Technology
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• v.4 no.1
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• pp.50-66
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• 2000

For a long time target maneuvers in tracking problem have been a difficult task to handle. Once a maneuvering such as abrupt change in target accelerations occur, the tracking fiter no longer yields a reasonable estimate of the target position. In order to resolve this cumbersome maneuvering problem. Advanced methods have here proposed : Colored noise, IE(Input Estimation), VD(Variable Dimension), IMM(Interaction Multiple Model), Jump-type processes and jerk model, etc. In this paper, tracking performance of the jerk model is analyzed. Jerk model in which the derivative of target acceleration is included as a state recently attracted considerable attraction. Firstly 3-dimensional Kalman filter is described on the basis of jerk model. Then using this filter, Monte-Carlo simulations are carried out and the filter formance with respect to the variation of jerk time-constant is analyzed. Especially, since jerk model's transient performance is expected to be poor, the performance of analysis of transient response of the model is included too.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.3
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• pp.246-252
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• 2005

Intelligent Space is a space where many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents, which provide human with services. To realize this, human and mobile robots have to approach each other as much as possible. Moreover, it is necessary for them to perform interactions naturally. It is desirable for a mobile robot to carry out human affinitive movement. In this research, a mobile robot is controlled by the Intelligent Space through its resources. The mobile robot is controlled to follow walking human as stably and precisely as possible. In order to follow a human, control law is derived from the assumption that a human and a mobile robot are connected with a virtual spring model. Input velocity to a mobile robot is generated on the basis of the elastic force from the virtual spring in this model. And its performance is verified by the computer simulation and the experiment.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.4
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• pp.429-441
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• 2002

This paper concerns extracting 3D motion information from a 3D input device in real time focused to enabling effective human-computer interaction. In particular, we develop a novel algorithm for extracting 6 degrees-of-freedom motion information from a 3D input device by employing an epipolar geometry of stereo camera, color, motion, and structure information, free from requiring the aid of camera calibration object. To extract 3D motion, we first determine the epipolar geometry of stereo camera by computing the perspective projection matrix and perspective distortion matrix. We then incorporate the proposed Motion Adaptive Weighted Unmatched Pixel Count algorithm performing color transformation, unmatched pixel counting, discrete Kalman filtering, and principal component analysis. The extracted 3D motion information can be applied to controlling virtual objects or aiding the navigation device that controls the viewpoint of a user in virtual reality setting. Since the stereo vision-based 3D input device is wireless, it provides users with a means for more natural and efficient interface, thus effectively realizing a feeling of immersion.