A method to transmit multiplexed digital video that potentially allows for video quality and capacity gains over conventional constant bit-rate (CBR) transmission is described. The method uses a joint rate control alg...
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A method to transmit multiplexed digital video that potentially allows for video quality and capacity gains over conventional constant bit-rate (CBR) transmission is described. The method uses a joint rate control algorithm that regulates the encoders during buffer congestion periods using bandwidth re-allocation and source rate control. A multichannel joint rate control algorithm is described and its performance simulated for MPEG encoded video on a typical Direct Broadcast Satellite (DBS) indicate significant capacity and/or quality gains conventional CBR transmission methods.
This paper describes an experimental investigation of adaptive control algorithms applied to aeroacoustic instabilities. The study is carried out on a cold how experimental rig, designed to reproduce the essential fea...
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This paper describes an experimental investigation of adaptive control algorithms applied to aeroacoustic instabilities. The study is carried out on a cold how experimental rig, designed to reproduce the essential features of acoustically coupled vortex shedding. This mechanism is the source of thrust oscillations in large segmented solid rocket motors. It is also found in a wide variety of combustion instabilities. Two adaptive control strategies are investigated and selected experimental results are reported. These results show the feasibility of control. The effect of the controller on the instability mechanism is analyzed and improvements to the control strategy are proposed. (C) 2000 Academic Press.
A novel approach is developed and demonstrated to characterize the sampling line effects during dynamic monitoring of fluid concentrations. The "sampling line" in this study refers to all components between ...
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A novel approach is developed and demonstrated to characterize the sampling line effects during dynamic monitoring of fluid concentrations. The "sampling line" in this study refers to all components between the point of fluid sampling and the point of analyzer sensor. In general, sampling lines introduce errors in measurements by altering the sample properties due to the fluid transport in the line as well as the adsorption and desorption of fluid constituents on the surfaces of the sampling components that come into contact with the sample fluid. A methodology based on a sampling line simulator is developed for taking these effects into account and correcting the measurements. The model is validated by direct experimental measurements using several different analyzers under various conditions. The sampling line simulator can be used to analyze the effect of various sampling configurations and operating conditions;this would be helpful in the design of sampling lines and their location. An algorithm is proposed that can be used to convert concentration values measured and reported by the analyzer to the concentration values at the point of sampling that are the actual and desired Values.
During stretch bending, considerable springback will occur after a tube has been plastically bent. To predict the springback, a simplified two-flange model for stretch bending of a rectangular tube has been developed ...
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During stretch bending, considerable springback will occur after a tube has been plastically bent. To predict the springback, a simplified two-flange model for stretch bending of a rectangular tube has been developed in which the strain history has been considered. A comparison has been made between the springback predicted by this model and experimental data, which shows rough agreement. Based on this model, a real time closed-loop control algorithm is developed.
In order to accurately identify the dynamic health of shearer, reducing operating trouble and production accident of shearer and improving coal production efficiency further, a dynamic health assessment approach for s...
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In order to accurately identify the dynamic health of shearer, reducing operating trouble and production accident of shearer and improving coal production efficiency further, a dynamic health assessment approach for shearer based on artificial immune algorithm was proposed. The key technologies such as system framework, selecting the indicators for shearer dynamic health assessment, and health assessment model were provided, and the flowchart of the proposed approach was designed. A simulation example, with an accuracy of 96%, based on the collected data from industrial production scene was provided. Furthermore, the comparison demonstrated that the proposed method exhibited higher classification accuracy than the classifiers based on back propagation-neural network (BP-NN) and support vector machine (SVM) methods. Finally, the proposed approach was applied in an engineering problem of shearer dynamic health assessment. The industrial application results showed that the paper research achievements could be used combining with shearer automation control system in fully mechanized coal face. The simulation and the application results indicated that the proposed method was feasible and outperforming others.
For assessing hearing aid algorithms, a method is sought to shift the threshold of a speech-in-noise test to (mostly positive) signal-to-noise ratios (SNRs) that allow discrimination across algorithmic settings and ar...
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For assessing hearing aid algorithms, a method is sought to shift the threshold of a speech-in-noise test to (mostly positive) signal-to-noise ratios (SNRs) that allow discrimination across algorithmic settings and are most relevant for hearing-impaired listeners in daily life. Hence, time-compressed speech with higher speech rates was evaluated to parametrically increase the difficulty of the test while preserving most of the relevant acoustical speech cues. A uniform and a non-uniform algorithm were used to compress the sentences of the German Oldenburg Sentence Test at different speech rates. In comparison, the non-uniform algorithm exhibited greater deviations from the targeted time compression, as well as greater changes of the phoneme duration, spectra, and modulation spectra. Speech intelligibility for fast Oldenburg sentences in background noise at different SNRs was determined with 48 normal-hearing listeners. The results confirmed decreasing intelligibility with increasing speech rate. Speech had to be compressed to more than 30% of its original length to reach 50% intelligibility at positive SNRs. Characteristics influencing the discrimination ability of the test for assessing effective SNR changes were investigated. Subjective and objective measures indicated a clear advantage of the uniform algorithm in comparison to the non-uniform algorithm for the application in speech-in-noise tests. (C) 2014 Acoustical Society of America.
Pedestrian detection with large intraclass variations is still a challenging task in computer vision. In this paper, we propose a novel pedestrian detection method based on Random Forest. Firstly, we generate a few lo...
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Pedestrian detection with large intraclass variations is still a challenging task in computer vision. In this paper, we propose a novel pedestrian detection method based on Random Forest. Firstly, we generate a few local templates with different sizes and different locations in positive exemplars. Then, the Random Forest is built whose splitting functions are optimized by maximizing class purity of matching the local templates to the training samples, respectively. To improve the classification accuracy, we adopt a boosting-like algorithm to update the weights of the training samples in a layer-wise fashion. During detection, the trained Random Forest will vote the category when a sliding window is input. Our contributions are the splitting functions based on local template matching with adaptive size and location and iteratively weight updating method. We evaluate the proposed method on 2 well known challenging datasets: TUD pedestrians and INRIA pedestrians. The experimental results demonstrate that our method achieves state-of-the-art or competitive performance.
作者：
Peserico, EMIT
Comp Sci & Artificial Intelligence Lab Cambridge MA 02139 USA
In the context of competitive analysis of online algorithms for the k-server problem, it has been conjectured that every randomized, memoryless online algorithm exhibits the highest competitive ratio against an offlin...
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In the context of competitive analysis of online algorithms for the k-server problem, it has been conjectured that every randomized, memoryless online algorithm exhibits the highest competitive ratio against an offline adversary that is lazy, i.e., that will issue requests forcing it to move one of its own servers only when this is strictly necessary to force a move on the part of the online algorithm. We prove that, in general, this lazy adversary conjecture fails. Moreover, it fails in a very strong sense: there are adversaries which perform arbitrarily better than any other adversary which is even slightly "lazier."
The storage energy of high frequency reactive component for the switched mode power converter is a new factor to assess the performance. The instability of the switched-mode converter under the peak current control mo...
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The storage energy of high frequency reactive component for the switched mode power converter is a new factor to assess the performance. The instability of the switched-mode converter under the peak current control mode is examined for its storage energy. Bifurcation and chaos of the storage energy in the inductor and capacitor are observed based on the stroboscopic map. The boundary of maximum storage energy is given to be an alternative to study the instability of the system in this study. Zero energy is obtained in stable period 1 and the storage energy with the same value and opposite direction is obtained in period 2. The simulation results of bifurcation and chaos of energy are obtained under different parameters and verified by experiment. The boundary of instability of energy stored in the reactive component under various parameters is formulated and a single equation can be used to indicate the factors. These results can provide a new guideline to design a stable system and provide a new control algorithm for power electronic system.
Extended discrete shearlet provides a directional multiresolution decomposition. It has been mathematically shown that extended discrete shearlet is a more efficient representation for the signals containing distribut...
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Extended discrete shearlet provides a directional multiresolution decomposition. It has been mathematically shown that extended discrete shearlet is a more efficient representation for the signals containing distributed discontinuities such as edges, compared to discrete wavelet. Multiresolution analyses such as curvelet and ridgelet share similar properties, yet their directional representations are significantly different from that of extended discrete shearlet. Taking advantage of the unique properties of directional representation of extended discrete shearlet, we develop an image watermark algorithm based on the largest information entropy. In proposed algorithm, firstly, 1-level extended discrete shearlet transform decomposes the test image into directional components on horizontal cone;each directional component reflects directional features and textured features differently. Next, the directional component whose information entropy is the highest is selected to carry watermark. Compared with related algorithms based on DWT and DCT, the proposed algorithm tends to obtain preferable invisibility when it is robust against common attacks.
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