We have studied, using DLTS, the EL-2 concentration in unintentionally doped OMVPE n-GaAs as a function of growth conditions such as partial pressure of Arsine, Trimethylgallium and growth temperature. The partial pre...
We have studied, using DLTS, the EL-2 concentration in unintentionally doped OMVPE n-GaAs as a function of growth conditions such as partial pressure of Arsine, Trimethylgallium and growth temperature. The partial pressure dependencies are used to develop a model for the formation of EL-2 in the OMVPE process. The EL-2 concentration also shows a near inverse dependence on growth temperature.
We introduce and examine a tool for analysing logics. This algebraic tool, coming from some ideas introduced by J. Piaget, provides condensed information about a logic (with emphasis on the behavior of a unary symbol)...
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This paper studies the problem of data gathering in hierarchical wireless ad hoc networks. In this scenario, a set of wireless devices generates messages which are addressed to the base station. As not all nodes can r...
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In this paper we present an algorithm to perform precoder adaptation and power control for rate maximization problem in ad-hoc networks where individual transmitterreceiver pairs communicate in interference channel sc...
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The performance of Networked Control systems (NCS) is directly affected mainly by time-varying network delays, so a specific approach to compensate their effects is usually required during the controller design proces...
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This paper presents GoPoMoSA, a Goal-oriented Process Modeling and Simulation Advisor that semi-automatically discovers suitable software Process Modeling and Simulation (SPMS) techniques for (inexperienced) process m...
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Future development of Intelligent Transportation systems (ITS) depends on Vehicular Ad-hoc Networks (VANETs) in which communications will help to improve traffic safety and efficiency through exchanging information am...
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Abstract In this work, the joint position tracking control problem of industrial robots is tackled. To cope with the model uncertainties and external disturbances affecting the robot, the Inverse Dynamic Controller (I...
Abstract In this work, the joint position tracking control problem of industrial robots is tackled. To cope with the model uncertainties and external disturbances affecting the robot, the Inverse Dynamic Controller (IDC) is combined with an approach based on higher order Sliding Mode Control (SMC) technique. We make use, in particular, of the so-called “Twisting” Second Order Sliding Mode Controller. Higher order SMC techniques transfer the inherent discontinuities to the time derivative of the input torque and this allows to obtain a continuous profile for the input torque, which is computed through integration of an appropriate discontinuous switching signal. Despite the chattering phenomenon is strongly attenuated, some residual problems (vibration and acustical noise) are still observed during the experimental implementation of such an approach in its standard formulation. To improve the system performance we suggest in this work an adaptation mechanism to adjust on-line the authority of the SMC. The logic is driven by a “sliding-mode indicator” that detects, on line, the occurrence of a sliding mode behaviour and uses this information for adaptation purposes. When large and fast control activity is demanded (e.g. to track fast reference trajectories) the adaptation unit reacts by automatically increasing the control authority of the SMC. On the other hand when small control authority is sufficient the control magnitude is lowered. Such a bidirectional adaptation logic significantly reduces the chattering. The proposed technique is theoretically analyzed and experimentally tested, and the results of comparative experiments are discussed in the paper.
In this paper we discuss the latest results obtained by a prototypical Spectral LADAR imager, an augmented implementation of conventional LADAR. This sensor uses an eye-safe shortwave infrared polychromatic laser-like...
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ISBN:
(纸本)9781618393487
In this paper we discuss the latest results obtained by a prototypical Spectral LADAR imager, an augmented implementation of conventional LADAR. This sensor uses an eye-safe shortwave infrared polychromatic laser-like source to obtain range-resolved 3D images with a backscatter spectrum uniquely associated to each detected point in 3D space. We show how 3D point cloud data augmented by spectral vectors at each point may significantly improve a UGVs situational awareness in complex terrain and contrast these attributes with the capabilities of other contemporary methods. In particular, we concentrate on natural and manmade terrain features that can pose serious operational challenges for fully autonomous vehicles. Spectrally classified point clouds generated by this demonstrator unit are presented for scenes typical of military operations.
With the fast technical improvement, flash memory based Solid State Drives (SSDs) are becoming an important part of the computer storage hierarchy to significantly improve performance and energy efficiency. However, d...
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