• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.147-148
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• 2015

This paper proposes a tile level rate control for High Efficiency Video Coding (HEVC). The proposed tile level rate control is designed by considering the multi-core platform of tile in HEVC. The proposed tile level rate control allocates the number of bits for each tile based on the predetermined weight generated from the current picture level rate control. According to the experimental results, the proposed tile level rate control for HEVC on multi-core platform loses negligibly the bitrate accuracy about 0.07% on average over the reference software HM-14.0.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1755-1766
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• 1999

A region-based video codec based on the H.263+ standard is examined and its associated novel rate control scheme is proposed in this work. The region-based coding scheme is a hybrid method that consists of the traditional block DCT coding and the object-based coding. Basically, we adopt H.263+ as the platform, and develop a fast macroblock-based segmentation method to implement the region-based video codec. The proposed rate control solution includes rate control in three levels: encoding frame selection, frame-layer rate control and macroblock-layer rate control. The goal is to enhance the visual quality of decoded frames at low bit rates. The efficiency of proposed rate control scheme applied to the region-based video codes is demonstrated via several typical test sequences.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.3
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• pp.152-160
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• 2012

This paper proposes a frame-level rate control algorithm for low delay video applications to reduce the fluctuations in the bitrate. The proposed algorithm minimizes the bitrate fluctuations in two ways with minimal coding loss. First, the proposed rate control applies R-Q model to all frames including the first frame of every group of pictures (GOP) except for the first one of a sequence. Conventional rate control algorithms do not use any R-Q models for the first frame of each GOP and do not estimate the generated-bit. An unexpected output rate result from the first frame affects the remainder of the pictures in the rate control. Second, a rate-distortion (R-D) cost is calculated regardless of the hierarchical coding structure for low bitrate fluctuations because the hierarchical coding structure controls the output bitrate in rate distortion optimization (RDO) process. The experimental results show that the average variance of per-frame bits with the proposed algorithm can reduce by approximately 33.8% with a delta peak signal-to-noise ratio (PSNR) degradation of 1.4dB for a "low-delay B" coding structure and by approximately 35.7% with a delta-PSNR degradation of 1.3dB for a "low-delay P" coding structure, compared to HM 8.0 rate control.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.163-171
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• 2001

This paper presents sliding mode control(SMC) method using target variation rate of Lypunov Function. SMC keeps the response of structure in sliding surface where structure is stable. It can design both linear controller and bang-bang controller. Linear control of previous research, however, can not make most of the performance of controller, because it is designed to satisfy the condition that the variation rate of Lyapunov function is minus. Also, incase of bang-bang controller, unnecessary large control force is generated. Presented method can utilize the capacity of controller efficiently by prescribing the target variation rate of Lyapunov function. Numerical simulation results indicate that the presented control methods can reduce the peak response larger than linear control, and it has control performance equivalent to bang-bang control.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.753-757
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• 2004

This paper describes a PC-based distributed multi-rate realtime control system using USB protocol, which is developed as a general motion controller. The control system consists of two control programs: one running at 1 kHz sampling rate on a PC with Linux and another running at 10 kHz sampling rate on a remotely located motion control card called RASID (remote axis serial interface device). Two programs communicates through USB at every 1 msec. A USB communication driver is developed to ensured the 1 msec desired communication time. The main program running on the PC generates reference trajectory at 1 kHz and send it to the RASID through USB and RASIDs located near the motors gather the sensor information and execute the low-level control at 10 kHz. The USB-based connectivity reduces the wiring harness and eventually the manufacturing cost of the machine. The multi-rate nature of the developed system improves the control capability. The effect of sampling rate is analyzed and simulated.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.84-90
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• 1997

We proposed a new bit-rate control algorithm to improve MPEG-2 video software encoder. Bit-rate Control plays an improtant role in picture quality of MPEG-2 encoder. To achieve better encoding performance such as controlling picture quality and using bity properly, we proposed a MPEG-2 bit-rate control algorithm using linear average Step-Size. Using a benchmark Program, we compared our algorithm with MPEG-2 Test Model 5. Our proposed algorithm showed better Bit-Rate Control with respect to used bits, picture quality.

• Journal of information and communication convergence engineering
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• v.5 no.1
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• pp.54-58
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• 2007

A real-time frame-layer rate control algorithm with a token bucket traffic shaper is proposed for distortion variation minimization. The proposed rate control method uses a non-iterative optimization method for low computational complexity, and performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. The proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performances than the existing rate control method.

• Journal of Bio-Environment Control
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• v.2 no.1
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• pp.27-36
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• 1993

Carbon dioxide enrichment for greenhouse crops has generally been a standard commercial practice for many years. Vegetable crops such as tomato, cucumber, and lettuce respond positively to the $CO_2$ enrichment. But improper $CO_2$ enrichment leads to physiological damage and economical loss. This study was carried out to develop a $CO_2$ concentration control algorithm considering growth stage and efficiency. The measurand was $CO_2$ consumption rate and top fresh weight that represents growth stage. The weight of top fresh lettuce as a whole in the tray was measured through a non-destructive method. The demand in $CO_2$ concentration according to growth stage was investigated. The results are summarized as follows. 1. The $CO_2$ consumption rate could be measured within the error of $\pm$ 15.4mg$CO_2$/hr in the range of $CO_2$ concentration of 500-1500ppm. 2. The weight of top fresh lettuce could be measured within the error $\pm$ 4.3g in the range of 0-1400g. 3. The $CO_2$ control model developed could determine an economical $CO_2$ supply rate considering $CO_2$ consumption rate and leakage rate. 4. The $CO_2$ control algorithm based on the control model was composed of feedforward control for maintaining a stable $CO_2$ concentration level, and feedback control with $CO_2$ consumption rate and top fresh weight for adapting to the change in $CO_2$ demand by growth stage. 5. For the performance test with the developed control algorithm on lettuce the decrease in $CO_2$ supply rate was obtained without a significant decrease in top fresh weight.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.244-249
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• 1998

In this paper, the hybrid state space self-tuning control technique Is studied within the framework of fuzzy systems and dual-rate sampling control theory. We show that fuzzy modeling techniques can be used to formulate chaotic dynamical systems. Then, we develop the hybrid state space self-tuning fuzzy control techniques with dual-rate sampling for digital control of chaotic systems. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the continuous-time optimal state feedback gains, the constructed discrete-time fuzzy system is converted into a continuous-time system. The developed optimal continuous-time control law is then convened into an equivalent slow-rate digital control law using the proposed digital redesign method. The proposed technique enables us to systematically and effective]y carry out framework for modeling and control of chaotic systems. The proposed method has been successfully applied for controlling the chaotic trajectories of Chua's circuit.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2056-2059
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• 2003

The rate control is very important to solve the difficulties arising from bit-rate on transmission through channel and to improve video quality. It is very important to point out that the amount of output bit obtained the encoding process using rate controller brings many problems on the transmission of channels and furthermore output bitstream decoded affects directly on the visual quality of displayed subject. In this paper, the effective rate control algorithm by rate-distortion modeling using MPEG-4 encoder is proposed. The proposed rate control has applied different weighting by VOP prediction type and even in the same VOP prediction type, the predicted reference allocates more bit. Through these bit allocation the minimization of distortion can be achieved preventing propagation of quantization error The amount of saved bitstream obtained by the proposed algorithm in this thesis is allocated to I-VOP using region of interest(ROI) selective enhancement on the next GOV encoding process and this process brought the improvement of visual quality.