Load sharing, circulation current, and bus voltage regulation are the main challenges of parallel converters operation in DC microgrids. For its simplicity, a droop controller is preferred for current sharing control ...
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Recent studies on MAC scheduling have shown that carrier sense multiple access (CSMA) algorithms can be throughput optimal for arbitrary wireless network topology. However, these results are highly sensitive to the un...
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ISBN:
(纸本)9781450321938
Recent studies on MAC scheduling have shown that carrier sense multiple access (CSMA) algorithms can be throughput optimal for arbitrary wireless network topology. However, these results are highly sensitive to the underlying assumption on 'static' or 'fixed' system conditions. For example, if channel conditions are time-varying, it is unclear how each node can adjust its CSMA parameters, so-called backoff and channel holding times, using its local channel information for the desired high performance. In this paper, we study 'channel-aware' CSMA (A-CSMA) algorithms in time-varying channels, where they adjust their parameters as some function of the current channel capacity. First, we show that the achievable rate region of A-CSMA equals to the maximum rate region if and only if the function is exponential. Furthermore, given an exponential function in ACSMA, we design updating rules for their parameters, which achieve throughput optimality for an arbitrary wireless network topology. They are the first CSMA algorithms in the literature which are proved to be throughput optimal under time-varying channels. Moreover, we also consider the case when back-off rates of A-CSMA are highly restricted compared to the speed of channel variations, and characterize the throughput performance of A-CSMA in terms of the underlying wireless network topology. Our results not only guide a high-performance design on MAC scheduling under highly time-varying scenarios, but also provide new insights on the performance of CSMA algorithms in relation to their backoff rates and underlying network topologies. Copyright 2013 ACM.
In this paper, a new object recognition framework is presented. The framework includes a variety of object recognition approaches based on Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), and th...
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This paper presents a successful implementation of an undergraduate robotics and virtual reality course that builds upon the synergies existing between these two areas in order to introduce computers and information t...
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It is concluded from the results of testing the frequency characteristics of the sub micron precision machine tool servo control system, that the existence of several oscillating modalities is the main factor that aff...
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It is concluded from the results of testing the frequency characteristics of the sub micron precision machine tool servo control system, that the existence of several oscillating modalities is the main factor that affects the performance of the control system. To compensate for this effect,several concave filters are utilized in the system to improve the control accuracy. The feasibility of compensating for several oscillating modalities with a single concave filter is also studied. By applying a modified Butterworth concave filter to the practical system, the maximum stable state output error remains under ±10 nm in the closed loop positioning system.
Application of projection pursuit learning in ship motion extreme short time prediction was presented. Relations among pitch time, roll, and vertical acceleration of ship was studied for top waves, longitudinal waves ...
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Application of projection pursuit learning in ship motion extreme short time prediction was presented. Relations among pitch time, roll, and vertical acceleration of ship was studied for top waves, longitudinal waves and roll waves. It was found that parametric projection pursuit achieved better accuracy with fewer parameters than a one hidden-layer sigmoidal neural networks.
This paper describes a fast and simple training method for face detection based on block gradient of the gray level. The gradient orientation is one of the most essential features to describe the image structure. In t...
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As an new optical instrument, Fiber Optical Gyroscope (FOG) is used in guidance and navigation system more and more. But the problem is that it can be disturbed by electromagnetic environment easily. According to appl...
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To efficiently extract local and global features in face description and recognition, a pyramid-based multi-scale LBP approach is proposed. Firstly, the face image pyramid is constructed through multi-scale analysis. ...
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