• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.215-220
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• 2005

In order to apply to land mine detection effectively, GPR using an optical electric field sensor as a receiver has been developed. The optical electric field sensor is very small and uses optical fiber instead of metallic coaxial cable. With the combination of these advantages and the bistatic radar system, it can be possible for an operator to measure quite flexible and safely. The sensor has been tested in stepped frequency radar system with frequency which consists of a vector network analyzer, a fixed double ridged horn antenna as transmitter. For considering effectiveness in real field, we applied impulse radar system, which consist of a digital oscilloscope and a impulse generator to produce the impulse. Detection of a PMN2 mine model was carried out by the impulse radar system at a sand pit. The PMN2 were detected clearly with sufficiently high resolution, the target contrast was almost the same while the scanning time decreased down to 1/100.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.935-939
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• 2015

This paper describes sensorless speed control of brushless DC motors by using direct torque control. Direct torque control offers fast torque response, robust specification of parameter changes, and lower hardware and processing costs compared to vector-controlled drives. In this paper, the current error compensation method is applied to the sensorless speed control of a brushless DC motor. Through this control technique, the controlled stator voltage is applied to the brushless DC motor such that the error between the stator currents in the mathematical model and the actual motor can be forced to decay to zero as time proceeds, and therefore, the motor speed approaches the setting value. This paper discusses the composition of the controller, which can carry out robust speed control without any proportional-integral (PI) controllers. The simulation results show that the control system has good dynamic speed and load responses at wide ranges of speed.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.5
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• pp.361-367
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• 2016

The intruder detection system using digital PIR sensor has the problem that it can't recognize human correctly. In this paper, we suggest a new intruder detection system based on analog PIR sensor to get around the drawbacks of the digital PIR sensor. The analog type PIR sensor emits the voltage output at various levels whereas the output of the digitial PIR sensor is binary. The signal captured using analog PIR sensor is sampled, and its frequency feature is extracted using FFT or MFCC. The extracted features are used for the input of neural networks. After neural network is trained using various human and pet's intrusion data, it is used for classifying human and pet in the intrusion situation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.40-46
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• 2006

It is required to develop a highly reliable attitude & orbit control system of satellite that is less expensive as the technology of satellite design & integration is recently matured dramatically. To accomodate this kind of needs, the two axis attitude control method for wheel-based momentum-biased satellite system whose momentum bias vector points to a certain direction(sun direction), is developed using simple but reliable sensors and actuator: three axis magnetometer and coarse sun sensor are used as sensors, and magnetic torque bars are used as actuator. Classical PD type controller design methodologies are applied on a satellite system for the two axis control with the proper assumptions. Nonlinear simulation results are included to demonstrate the long term stability and the performance of closed-loop system design results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1064-1071
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• 2006

In electric motor coaches, the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the weight of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, the electric motor coach has slip phenomena. This paper proposes a re-adhesion control based on disturbance observer and sensor-less vector control. The numerical simulation and experimental results point out that the proposed readhesion control system has the desired driving wheel torque response for the tested bogie system of electric coach. Based on this estimated adhesive effort, the re-adhesion control is performed to obtain the maximum transfer of the tractive effort.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.5
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• pp.39-53
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• 2007

The purpose of this paper is the development of a compensation algorithm by which the interoperability of fingerprint recognition can be improved among various different fingerprint sensor. In order to compensate for the different characteristics of fingerprint sensor, an initial evaluation of the sensors using both the ink-stamped method and the flat artificial finger pattern method was undertaken. This paper proposes Common resolution method and Relative resolution method for compensating different resolution of fingerprint images captured by disparate sensors. Both methods can be applied to image-level and minutia-level. In order to compensate the direction of minutiae in minutia-level, Unit vector method is proposed. The EER of the proposed method was improved by average 64.8% better than before compensation. This paper will make a significant contribution to interoperability in the system integration using different sensors.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1214-1218
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• 2010

As a study on activities associated with sleeping, this paper is aimed to trace a behavior log by differentiating human behavior patterns. Toward this research purpose, we define a behavior log and a simplified feature vector about human behavior patterns associated with sleeping. Then, based on thresholds of the feature vector, we did experiments applying the individual-base behavior pattern decision algorithm to human behavior patterns. The important results derived from these experiments indicate that the proposed approach reflecting individual behavioral characteristics is more useful than the existing single group approach.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.1
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• pp.88-94
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• 2000

In this paper, a parameter estimation method for a vector control of induction motors is presented. It can be easily implemented to the inverters in the industrial fields such as continuous process line, which requires the high performance of torque control, because of being estimated under the condition of the actual operating states. Also, this method nems no additional hardware such as voltage sensors and measuring equipments by the estimation of output voltage, and has good accuracy and repeatability by observing the variation of the stator voltage due to estimation errors. Experimental results verify the validity and usefulness of the proposed estimation method in the industrial fields.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.247-254
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• 2013

The task of 3D gesture recognition for controlling equipments is highly challenging due to the propagation of 3D smart TV recently. In this paper, the AdaBoost algorithm is applied to 3D gesture recognition by using Kinect sensor. By tracking time interval trajectory of hand, wrist and arm by Kinect, AdaBoost algorithm is used to train and classify 3D gesture. Experimental results demonstrate that the proposed method can successfully extract trained gestures from continuous hand, wrist and arm motion in real time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.169-172
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• 2007

This paper presents circuit models and control algorithms of distributed generation system(DGS) which consists of Z-type converter and PWM inverter. Z-type converter which employs both the L and C passive components and shoot-through zero vectors instead qf the conventional DC/DC converter in order to step up DC-link voltage. Discrete time sliding mode control with the asymptotic observer is used for current control. This system am be used for power conversion of DC renewable energy.