This paper presents dynamic behaviors of autonomous solid oxide fuel cells (SOFC) with AC bus control. Both voltage and frequency control are utilized to achieve load-sharing of the studied SOFC feeding isolated loads...
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This paper presents dynamic behaviors of autonomous solid oxide fuel cells (SOFC) with AC bus control. Both voltage and frequency control are utilized to achieve load-sharing of the studied SOFC feeding isolated loads. A DC-to-DC converter is connected to the output terminals of the studied SOFC for stabilizing output voltage and current fluctuations under different loading conditions. The PWM inverter connected to the output terminals of the DC-to-DC converter is operated under voltage-controlled mode to regulate the voltage profile across the connected loads. It can be concluded from the simulation results that the proposed voltage and frequency droop controllers of the PWM inverter may operate satisfactory under stand-alone mode.
This paper is dealing with redundant optoelectronic data transmission with special respect to laser channels. The concept of the generalized erasure channel (GEC) is used to determine the probability of undetected err...
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This paper is dealing with redundant optoelectronic data transmission with special respect to laser channels. The concept of the generalized erasure channel (GEC) is used to determine the probability of undetected error for some binary symmetric and non-symmetric channels protected by appropriate codes. In detail, communication via different binary symmetric channels (BSCs), generalized erasure channels and symmetrized binary non symmetric channels (BNSCs) is investigated. Simple upper bounds are given, relating the new formulas to that one of the BSC Finally the results in connection with an inequality for proper codes are applied to multi wavelength optical transmission through channels generated by semiconductor lasers.
In this paper, the feasibility of using active noise control inside personal computers is demonstrated by applying an adaptive filter to Hewlett-Packard's Blackbird 002 Gaming PC. Conditions relating the control s...
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In this paper, the feasibility of using active noise control inside personal computers is demonstrated by applying an adaptive filter to Hewlett-Packard's Blackbird 002 Gaming PC. Conditions relating the control signals and the sound heard by an external listener are presented as a means of evaluating the hardware design before applying the adaptive filter. A multichannel stochastic adaptive filter is derived by vectorizing the equations and applying gradient descent and Newton's method. For implementation purposes, data-based approximations to the gradient and hessian are provided. It is shown that a 6dB reduction in sound pressure level is obtainable by adding reference microphones, error microphones, a speaker, and some acoustical foam into the system even though the length of the noise cancelation system is small, approx. 6”, compared to the fundamental wavelength of the noise, approx 23”.
The robust stability and stabilization, and H-infinity control problems for discrete-time Markovian jump singular systems with parameter uncertainties are discussed. Based on the restricted system equivalent （r.s.e....
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The robust stability and stabilization, and H-infinity control problems for discrete-time Markovian jump singular systems with parameter uncertainties are discussed. Based on the restricted system equivalent （r.s.e.） transformation and by introducing new state vectors, the singular system is transformed into a discrete-time Markovian jump standard linear system, and the linear matrix inequality （LMI） conditions for the discrete-time Markovian jump singular systems to be regular, causal, stochastically stable, and stochastically stable with 7- disturbance attenuation are obtained, respectively. With these conditions, the robust state feedback stochastic stabilization problem and H-infinity control problem are solved, and the LMI conditions are obtained. A numerical example illustrates the effectiveness of the method given in the oaoer.
In noncooperative Iris recognition one should deal with uncontrolled behavior of the subject as well as uncontrolled lighting conditions. That means imperfect focus, contrast, brightness, and orientation among the oth...
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In noncooperative Iris recognition one should deal with uncontrolled behavior of the subject as well as uncontrolled lighting conditions. That means imperfect focus, contrast, brightness, and orientation among the others. To cope with this situation we propose to take iris images at both near infrared (NIR) and visible light (VL) and use them simultaneously for recognition. In this paper, a novel approach for iris recognition is proposed so that extracted features of NIR and VL images are fused to improve the recognition rate. When the images do not have enough quality due to focus, contrast, etc., effects of feature fusion is more pronounced. This is the situation in UTIRIS database, which is used in our experiments. Experimental results show that the proposed approach, especially in small training samples, leads to a remarkable improvement on recognition rate compared with either NIR or VL recognition.
Understanding the primatespsila visual system has been one of the challenging problems of different groups of scientists for years. Though many studies, from physiology and neuroscience to computer vision, are done on...
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Understanding the primatespsila visual system has been one of the challenging problems of different groups of scientists for years. Though many studies, from physiology and neuroscience to computer vision, are done on different aspects of visual processing in the cortex, a comprehensive computational model of visual cortex is still missing. We have implemented a computational model of object recognition in ventral visual pathway in our previous work. This hierarchical model covers visual areas V1/V2, V4/PIT, and AIT sending inputs to the Prefrontal Cortex (PFC) for categorization. To extend our model, in this work, we have added a simple model of motion detection in neurons of areas V1 and MT of the dorsal stream to our previous model. This has enabled the model to perform another principal function of the visual cortex, i.e., motion perception.
Along with the thorough development and application for Web services, the security of it has taken people¿s attention more and more. While Web services security (WSS) can exchange safe SOAP message and enhance th...
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Along with the thorough development and application for Web services, the security of it has taken people¿s attention more and more. While Web services security (WSS) can exchange safe SOAP message and enhance the security of Web services, it will also have certain influence to the performance of Web services. In order to satisfy the security of it , to reduce the performance influence of Web services and to solve both the requester and provider side cannot recognize the security token, in this paper, we aim at proposing a SOAP information registration and security token proxy model for Web services (SIRSTPM). We has carried on the formalizing and verifying of this model. The result of theoretical verification shows this model is secure and effective. This model is helpful for solving the problem between security and performance contradiction as well as the token cannot be recognized by both the requester and the provider.
We propose a constrained, three-dimensional, nonparametric, entropy-based, coupled, multi-shape approach to segment subcortical brain structures from magnetic resonance images (MRI). The proposed method uses PCA to de...
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We propose a constrained, three-dimensional, nonparametric, entropy-based, coupled, multi-shape approach to segment subcortical brain structures from magnetic resonance images (MRI). The proposed method uses PCA to develop shape models that capture structural variability. It integrates geometrical relationship between different structures into the algorithm by coupling them (limiting their independent deformations). On the other hand, to allow variations among coupled structures, it registers each structure separately when building the shape models. It defines an entropy-based energy function, which is minimized using quasi-Newton algorithm. To this end, probability density functions (pdf) are estimated iteratively using nonparametric Parzen window method. In the optimization algorithm, constraints are used to improve segmentation quality. These constraints are extracted from training data. Sample results are given for the segmentation of caudate, hippocampus, and putamen, illustrating highly superior performance of the proposed method compared to the most similar methods in the literature.
Driver distraction has been recognized as a significant cause of traffic incidents. Therefore, the aim of this study was to investigate Electroencephalography (EEG) dynamics in response to distraction during driving. ...
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Driver distraction has been recognized as a significant cause of traffic incidents. Therefore, the aim of this study was to investigate Electroencephalography (EEG) dynamics in response to distraction during driving. To study human cognition under specific driving task, we used Virtual Reality (VR) based driving simulation to simulate events including unexpected car deviations and mathematics questions (math) in real driving. For further assessing effects of the stimulus onset asynchrony (SOA) between the deviation onset and math presented on the EEG dynamics, we designed five cases with different SOA. The scalp-recorded EEG channel signals were first separated into independent brain sources by Independent Component Analysis (ICA). Then, the Event-Related-Spectral-Perturbations (ERSP) measuring changes of EEG power spectra were used to evaluate the brain dynamics in time-frequency domains. Results showed that increases of theta band (5approx7.8 Hz) and beta band (12.2approx17 Hz) power were observed in the frontal cortex. Results demonstrated that reaction time and multiple cortical EEG sources responded to the driving deviations and math occurrences differentially in the stimulus onset asynchrony. Results also suggested that the theta band power increase in frontal area could be used as the distracted indexes for early detecting driver's inattention in the future.
This article gives a capsule view of research on rough set theory and applications ongoing at universities and laboratories in China. Included in this capsule view of rough set research is a brief description of the f...
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