• Journal of ILASS-Korea
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• v.11 no.2
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• pp.105-112
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• 2006

A unique feature of fluidic atomizers is that the nozzle geometry produces a thin capillary Jet which is forced to oscillate on a 2-dimensional plane through the use of a passive feedback mechanism. The objective of the current work is to characterize the influence of the stagnation pressure at the nozzle exit, jet oscillation and stretching on the breakup properties of the capillary ligament. To achieve this, shadow graph technique is used to measure size, shape, velocity and the number density of the droplets as a function of the position within the spray fan. The breakup length, defined as the radial distance from the breakup point, is analyzed as a function of the non-dimensional parameters. Finally, a kinematic model is developed to simulate the breakup of the oscillating jets at low stagnation pressures. Using the existing jet breakup theories, the model is used to predict the size and diameter distribution of the droplets after primary atomization.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.579-582
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• 1995

Recently, the vision system has the wide and growing' application field on account of the vast information from that visual mechanism. Especially, in the control field, the vision system has been applied to the industrial robot. In this paper, the object tracking and grasping task is accomplished by the robot vision system with a camera in the robot hand. The camera setting method is proposed to implement that task in a simple way. In spite of the calibration error, the stable grasping task is achieved using the tracking control algorithm based on the vision feature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.704-706
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• 2012

In this paper, we proposes a document summarization method using the term weighting. The proposed method can minimize the user intervention to use the pseudo relevance feedback. It also can improve the quality of document summaries because the inherent semantic of the sentence set are well reflected by term weighting derived from semantic feature.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.134-137
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• 2002

This paper presents a robot manipulator kinematic motion control scheme based on velocity feedback loop. The desired joint velocity is obtained by the feature-based visual servoing and is used in the joint velocity control loop system for trajectory control of the robot manipulator. The asymptotic stability of the closed loop system is shown by the Lyapunov method. Effectiveness of the proposed method is shown by simulation and experimental results on a robot manipulator with two degree of freedom.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.47-50
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• 1990

Deafs cannot speak straight voice as normal people in lack of feedback of their pronunciation, therefore speech training is required. In this study, fundamental frequency, intensity, formant frequencies, vocal tract graphic and vocal tract area function, extracted from speech signal, are used as feature parameter. AR model, whose coefficients are extracted using inverse filtering. is used as speech generation model. In connect ion between vocal tract graphic and speech parameter, articulation distances and articulation distance functions in selected 15-intervals are determined by extracted vocal tract areas and formant frequencies.

• Journal of Sensor Science and Technology
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• v.13 no.3
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• pp.236-243
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• 2004

In this paper, we proposed a brain-computer interface system using EEG signals. It can generate 4 direction command signal from EEG signals captured during imagination of subjects. Bandpass filter used for preprocessing to detect the brain signal, and the power spectrum at a specific frequency domain of the EEG signals for concentration status and non-concentration one is used for feature. In order to generate an adequate signal for controlling the 4 direction movement, we propose a new interface system implemented by using a support vector machine and a time-multiplexing method. Moreover, bio-feed back process and on-line adaptive pattern recognition mechanism are also considered in the proposed system. Computer experimental results show that the proposed method is effective to recognize the non-stational brain wave signal.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.628-634
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• 2002

A capacitor-charging power supply using high frequency inverter technology is strongly recommended for the charging section of the pulsed power supplies. A high frequency inverter swiching makes the overall system size small. The command-charging feature can guarantee the higher reliability of switching function. The protection circuit can be easily included in the system and the good regulation of charging voltage can be acieved by the feedback system. Several modules can be stacked to supply required output power and a failed module can be easily replaced. A 50-kV, 35-kW capacitor charging power supply is developed. In this paper the detailed design and test results of a prototype unit are presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.305-306
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• 2013

In this paper, we proposes a document summarization method using the weighting based on cloud. The proposed method can minimize the user intervention to use the relevance feedback. It also can improve the quality of document summaries because the inherent semantic of the sentence set are well reflected by term weighting derived from semantic feature using nonnegative matrix factorizaitno based cloud.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2001.05a
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• pp.152-158
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• 2001

Since web_based tutoring systems are generally composed with passive and static hypertext, they could not provide adaptive learning environments according to learning ability of each student. In this study, we suggest an intelligent tutoring system, which grasps the learning state of student and provides each student with dynamic learning materials suitable to individual feature based on learning result. It is an agent based system, in which, courseware knowledge for learning is effectively constructed, the proper feedback according to learning assessment is inferred, and it is given to each student.

• Proceedings of the IEEK Conference
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• summer
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• pp.259-262
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• 2004

In most of the character recognition systems, the method of template matching or statistical method using hidden Markov model is used to extract and recognize feature shapes. In this paper, we used modified chain-code which has 8-directions but 4-codes, and made the chain-code of hand-written character, after that, converted it into transition chain-code by applying to HMM(Hidden Markov Model). The transition chain code by HMM is analyzed as signal flow graph by Mason's theory which is generally used to calculate forward gain at automatic control system. If the specific forward gain and feedback gain is properly set, the forward gain of transition chain-code using Mason's theory can be distinguished depending on each object for recognition. This data of the gain is reorganized as tree structure, hence making it possible to distinguish different hand-written characters. With this method, $91\%$ recognition rate was acquired.