• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.45-46
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• 2010

In this paper, the static overmodulation is proposed for the 2-phase full bridge inverter. The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation range. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. Simulation and experimentation results demonstrate the effectiveness of the proposed algorithms.

• Annual Conference of KIPS
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• 2000.10a
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• pp.767-770
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• 2000

저 대역 망에서 동영상을 실시간으로 전송하기 위해서는 높은 압축률을 요구한다. 따라서 복원된 이미지는 화질 저하라는 현상을 낳게 되는데 본 논문에서는 복원 이미지의 화질 보상에 대한 방법으로 디코더에서 블록 아티팩을 제거하고 복원 이미지를 선명하게 하는 알고리즘을 제안한다. 여기서 화질 보상은 원본 이미지와 동일하게 만드는 것이 아니라 인간이 더 좋은 영상으로 인식하도록 하는 걸 목적으로 한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.166-175
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• 2001

The high speed tracking control of a 6-6 Stewart platform manipulator (SPM) normally requires knowledge of its complex full dynamics and measurement of its base motion when the SPM operates on a motion nit. In this study, an enhanced sliding mode control scheme has been developed, which is based on the reduced dynamics, not necessitating measurement of the base motion. The enhanced sliding mode control implemented with the perturbation compensation and modified reaching phase alleviation functions has been successfully employed for high speed tacking control of the laboratory SPM, when it is subjected to a virtual base motion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4489-4501
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• 2014

We propose a novel lane detection method based on classification in image sequences. Both structural and statistical features of the extracted bright shape are applied to the neural network for finding correct lane marks. The features used in this paper are shown to have strong discriminating power to locate correct traffic lanes. The traffic lanes detected in the current frame is also used to estimate the traffic lane if the lane detection fails in the next frame. The proposed method is fast enough to apply for real-time systems; the average processing time is less than 2msec. Also the scheme of the local illumination compensation allows robust lane detection at nighttime. Therefore, this method can be widely used in intelligence transportation systems such as driver assistance, lane change assistance, lane departure warning and autonomous vehicles.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.193-196
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• 2002

본 논문은 현재 국내 디지털 오디오 방송의 잠정 표준으로 채택된 Eureka-147 수신 시스템의 심볼 동기보상 방법에 관한 내용이다. 제안하는 방법을 이용하면 대략적 심볼 동기와 미세 심볼 동기를 모두 수행하는 일반적인 OFDM 심볼 동기 방법 대신 대략적 동기와 새로운 전처리 과정을 포함하는 보상 방법을 사용하여 수신 성능을 보장할 수 있다. 기본 아이디어는 시스템의 수신 성능에 큰 영향을 미치는 (+) 방향의 OFDM 심볼 동기 추정 오류의 발생 확률을 줄이는 것이다.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.265-269
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• 1994

The switching dead time avoiding a bridge leg short circuit in PWM voltage source inverter produces distortions of the controlling inverter output performance such as current waveform, voltage vector, and torque. In this paper, the influence of dead time is investigated. The on-line space voltage vector modulation method is used for current controller. It is possible to compensate dead time by space voltage vector modulation which generates additional pulse compensating voltage distortion caused by dead time. In addition, narrow pulse which is generally neglected can be compensated. All the algorithms, including field-oriented control are performed by one chip microprocessor 80C196MC and DSP TMS320C31. Experimental results probe that the proposed scheme provides a good inverter output performance.

• Journal of Satellite, Information and Communications
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• v.2 no.1
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• pp.7-13
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• 2007

A new and effective Doppler effects compensation method based on constellation estimation as well as an average power saving strategy by modified modulation scheme utilizing zero point constellation are presented with theoretical analysis and relevant simulations. The suggested schemes are proved to be very effective for satellite OFDM signals relayed by power limiting transponder for the mobile terminal on high speed vehicles.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.810-817
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• 2006

This paper presents a rotational motion estimation and correction technique for digital image stabilization. An equivalent rotation model is derived so as to accommodate a combined rotational and the translational motion. Thanks to this simplification, the suggested estimation algorithm can directly find the rotational center using geometric characteristic of local motion vectors instead of using searching method. And we also present recursive version of frame to reference algorithm(FRA) for the real time implementation. The proposed DIS system does not require time consuming parameter searching process, while showing comparatively good performance compared with the previous ones. To show the effectiveness of the DIS scheme, the algorithm has been implemented on the DSP based hardware system and experimental results are also discussed.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.147-154
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• 2000

This paper proposes an overmodulation strategy for space-vector PWM(SVPWM). The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation region. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. The practical implementation is simple and it is applied to improve an output voltage of SVPWM controlled AC Motor in the steady-state. The characteristic of the proposed strategy is confirmed by simulations and experiments for a V/F control of a induction motor.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.3
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• pp.185-190
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• 2009

A scheme of expert system based on iterative learning control is proposed. Iterative learning control can obtain control experience from the historical data to build the knowledge base of expert system. Considering some uncertain factors, a flexible measure is adopted in iterative learning control (ILC). Simulation proves the feasibility and effect of the air conditioning control expert system based on flexible iterative learning control (F-ILC). Finally, a feedback compensation unit is incorporated against irregular heavy disturbance.