In this paper a method to estimate the initial rotor position of the switched reluctance motor (SRM) at the stand still condition is proposed. The proposed method can be implemented by the simple microcontroller based...
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In this paper a method to estimate the initial rotor position of the switched reluctance motor (SRM) at the stand still condition is proposed. The proposed method can be implemented by the simple microcontroller based system, and it is not necessary to know the magnetization curves. The impulse gate drive signal is applied and the winding current is detected and its approximate value is used for calculating the rotor position. The compensation method to reduce the estimation error thorough one cycle is also mentioned. The proposed method is implemented with the 6-stator-pole and 4- rotor-pole, 1.5 kW 3-phase switched reluctance motor.
In this paper, a wavelet-based speckle-removing algorithm is represented and tested on synthetic aperture radar (SAR) images. The SAR image is first transformed using a dyadic wavelet transform. The noise in the wavel...
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Robust visual tracking is always a challenging but yet intriguing problem owing to the appearance variability of target objects. In this paper we propose a novel method to handle large changes in appearance based on o...
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Robust visual tracking is always a challenging but yet intriguing problem owing to the appearance variability of target objects. In this paper we propose a novel method to handle large changes in appearance based on online real-value boosting, which is utilized to incrementally learn a strong classifier to distinguish between objects and their background. By incorporating online real boosting into a particle filter framework, our tracking algorithm shows a strong adaptability for different target objects which undergo severe appearance changes during the tracking process.
Grid computing emerges as an effective technology to couple geographically distributed resources and solve large-scale computational problems in wide area networks. There are several popular grid platforms, such as UN...
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ISBN:
(纸本)9780769530482;0769530486
Grid computing emerges as an effective technology to couple geographically distributed resources and solve large-scale computational problems in wide area networks. There are several popular grid platforms, such as UNICORE and Globus Toolkit. Many famous grid projects are constructed with these platforms, each of which manages different distributed resources. In order to aggregate resources managed by different grid platforms, it is necessary to implement the interoperation among these grid platforms. Security interoperation is one of key issues for the interoperation. CGSP (ChinaGrid Support Platform) and VEGA are two popular grid platforms in China. To achieve security interoperation between these two platforms, four mapping policies, including user-user mapping, user-agora mapping, role-user mapping, role-agora mapping, are proposed in this paper. The security interoperation process is proposed based on SAML specification and the mapping policies. We also analyze the flexibility of mapping policies and the security of the interoperation process.
In networked control systems, because of limits on communication rates, control waveforms are frequently piece-wise constant with limits on rates at which they can switch levels. It is, therefore, natural to expect ev...
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In networked control systems, because of limits on communication rates, control waveforms are frequently piece-wise constant with limits on rates at which they can switch levels. It is, therefore, natural to expect event-triggered control switchings to perform more efficiently than time-triggered ones. This article verifies the validity of this supposition. A method for designing good level-triggered control schemes is obtained by reducing the continuous time problem to one in discrete time. Then, by numerical procedures, the performance of the level-triggered scheme is computed for comparison with that of the periodically switched control scheme.
It now becomes a trend to implement the interconnections between resources as well as services in ubiquitous systems. Attribute-based authorization mechanisms, protocols and systems are gaining in popularity, such as ...
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It now becomes a trend to implement the interconnections between resources as well as services in ubiquitous systems. Attribute-based authorization mechanisms, protocols and systems are gaining in popularity, such as SAML, XACML, Shibboleth, etc. However, their management efficiency could be further improved. The Role-based Access control (RBAC) mechanism is widely accepted as a general mechanism for authorization management. However, RBAC is still not flexible enough to address various application scenarios in ubiquitous systems. We propose a new architecture for access control in ubiquitous systems that impose attribute and status constraints on the RBAC model, which can significantly enhance the generality and flexibility of authorization by integrating the advantages of RBAC and attributed- based access control models. Moreover, the state mechanism proposed in this architecture captures the states of the authorization elements so as to reflect the outcomes of the authorization control. Finally, we analyze the flexibility and generality of this architecture in ubiquitous systems.
Scale invariant feature transform (SIFT) proposed by Lowe has been widely and successfully applied to object detection and recognition. However, the representation ability of SIFT features in face recognition has rare...
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Scale invariant feature transform (SIFT) proposed by Lowe has been widely and successfully applied to object detection and recognition. However, the representation ability of SIFT features in face recognition has rarely been investigated systematically. In this paper, we proposed to use the person-specific SIFT features and a simple non-statistical matching strategy combined with local and global similarity on key-points clusters to solve face recognition problems. Large scale experiments on FERET and CAS-PEAL face databases using only one training sample per person have been carried out to compare it with other non person-specific features such as Gabor wavelet feature and local binary pattern feature. The experimental results demonstrate the robustness of SIFT features to expression, accessory and pose variations.
In this Letter, we indicate that the proposed sufficient condition in Letter [Z. Li, G. Feng, D., Hill, Phys. Lett. A 359 (2006) 42] does not hold, which cannot guarantee that the states of complex network with coupli...
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In this Letter, we indicate that the proposed sufficient condition in Letter [Z. Li, G. Feng, D., Hill, Phys. Lett. A 359 (2006) 42] does not hold, which cannot guarantee that the states of complex network with coupling delays globally exponentially synchronize with a desired orbit and it only applies to globally asymptotical synchronization with a desired orbit. For correcting the mistakes, a correct version of globally exponential synchronization is given and proved in this Letter.
The application of power quality parameters measurement algorithms requires utilization of computational methods which transform the signal from the time- to the frequency-domain. Currently, the most frequently applie...
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The application of power quality parameters measurement algorithms requires utilization of computational methods which transform the signal from the time- to the frequency-domain. Currently, the most frequently applied method is the fast Fourier transformation (FFT). Because of the amendment of the proper power quality standards, it is also necessary to consider of implementation discrete Fourier transformation (DFT) algorithms. Considering the number of computations, DFT is more complicated than FFT. This paper presents basic analog-to-digital conversion parameters, which are defined in the norms, the time duration analysis of DFT algorithms, considering described assumptions and comparing them to FFT. Codes created in C and assembler languages, as well as the Matlab/Simulink environment, were taken into account. The software including the aforementioned codes was implemented in a low-cost power quality measurement system based on the TMS320c6713 floating point DSP processor from Texas Instruments. In the software, a real time DSP/BIOS operation system was used. Multi thread programming in power quality measurement systems was presented, and an analysis of computational efficiencies of the systems based on the TMS320c6 713 DSP processors was performed.
In this paper we propose a novel reactive multi-path routing protocol for wireless (and vehicular) ad-hoc networks. The proposed scheme tries to establish and maintain local multiple paths to a certain destination, in...
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In this paper we propose a novel reactive multi-path routing protocol for wireless (and vehicular) ad-hoc networks. The proposed scheme tries to establish and maintain local multiple paths to a certain destination, instead of finding multiple global paths between the source and destination nodes as most other multipath solutions do. To achieve this, we adopt and modify the well-known reactive routing protocol AODV. Using this scheme, source node and intermediate nodes are able to find a better next-hop dynamically when the network topology or traffic activity are changed. A cost function is given to let the related nodes to make decisions. NS-2 simulations show that our scheme gives significant improvement in terms of packet delivery ratio, routing overhead, and energy consumption.
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