This paper describes a new method for how interfering MIMO links might transmit more effectively in a random access network. We assume perfect transmitter-side channel state information, zero-forcing pre-coding to gua...
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This paper describes a new method for how interfering MIMO links might transmit more effectively in a random access network. We assume perfect transmitter-side channel state information, zero-forcing pre-coding to guarantee no interference on links that have already won access, and zero-forcing receiver processing at the still-contending links to suppress interference from the links that have already won. We define an effectiveness metric, the Instantaneous Equivalent SNR Percentile (IESP), in which the Equivalent SNR is the SNR of a single-input-single-output (SISO) link that would have the same capacity of a MIMO link after its interference constraints have been met and the IESP is the percentile of the Equivalent SNR, assuming independent Rayleigh fading. We propose that fairness among heterogeneous contending links be realized by giving the shorter contention window to the link with the higher IESP based on its own distribution, enabling links with few antennas to compete with links that have many antennas. Through simulation of the sum capacity of the winning set of links, the proposed contention window design is shown to provide a higher sum capacity than contention based on equal-sized windows.
As well-known, model predictive control is closely related to optimal control. This paper studies relationships between them and provides a unified framework for optimality analysis of model predictive controllers (MP...
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As well-known, model predictive control is closely related to optimal control. This paper studies relationships between them and provides a unified framework for optimality analysis of model predictive controllers (MPC). The optimality is evaluated by comparing total performance of MPC with finite and infinite horizon optimal cost. Based on relaxed value iteration method, upper and lower bounds of optimality evaluation functions are expressed explicitly in terms of optimization horizon. These results reveal detailed characteristics on performance of closed-loop MPC systems due to using “receding horizon optimization” implementation style.
All currently available Network-based Intrusion Detection systems (NIDS) rely upon passive protocol analysis which is fundamentally flawed as an attack can evade detection by exploiting ambiguities in the traffic stre...
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Temperature is an important factor that limits the current-carrying capability of overhead transmission lines. An online estimation approach is proposed in this study to dynamically track the temperature of transmissi...
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ISBN:
(纸本)9781479975389
Temperature is an important factor that limits the current-carrying capability of overhead transmission lines. An online estimation approach is proposed in this study to dynamically track the temperature of transmission lines and thereby fully use their capability. In the proposed approach, the temperature is represented as a function of the transmission loss and current. A Kalman Filter model is set up to track the dynamic change of the temperature. The proposed approach uses only the accessible electrical measurements to form the estimation models and is therefore more practical than other approaches. Test results on a real 110 KV transmission line illustrate the effectiveness of the proposed approach.
Sensor networks have been widely utilized in various applications. In large wind farms, numerous sensor nodes are deployed across the field for monitoring purpose. They are required to work in harsh environment and us...
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Sensor networks have been widely utilized in various applications. In large wind farms, numerous sensor nodes are deployed across the field for monitoring purpose. They are required to work in harsh environment and usually undergo unexpected failures. This paper introduces a new method to model nodes of sensor networks by using two-layer neural networks (NN). Each node's dynamics and interconnections with other sensor network nodes are integrated into the model, whose accuracy is guaranteed by the NN's universal approximation property. Furthermore, the model can be subsequently employed to detect any incipient failures which can be modeled as a nonlinear function of state and input variables. An additional NN along with a novel simplified updating law is utilized for self-diagnostics, whose output can declare a failure alarm if it exceeds a certain threshold. Mathematical analysis is substantiated with simulation results.
Walking on irregular terrain is usually a common task for a quadruped robot. It is however difficult to control the robot in this situation as undesirable impulse force by collision between the foot of robot and obsta...
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Walking on irregular terrain is usually a common task for a quadruped robot. It is however difficult to control the robot in this situation as undesirable impulse force by collision between the foot of robot and obstacles makes the robot unstable. This paper presents a hybrid Force-Posture Feedback Compensation (FPFC) controller for a quadruped robot with high payload walking on irregular terrain. In order to make the robot walk stably on irregular terrain, the proposed controller utilizes the feedback signals detected by force sensor and gyroscope to adjust every leg of the robot in real-time. The foot trajectory is scheduled based on the Bezier curve method in order to improve the stability of quadruped robot. Simulations of crawling gait on irregular terrain have been performed. The results have verified that the proposed methods have better stability and performance for walking on the irregular terrain.
Load distribution is a key technology in hot strip rolling process, which directly influences strip product quality. A multi-objective load distribution model, which takes into account the rolling force margin balance...
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Load distribution is a key technology in hot strip rolling process, which directly influences strip product quality. A multi-objective load distribution model, which takes into account the rolling force margin balance, roll wear ratio and strip shape control, is presented. To avoid the selection of weight coefficients encountered in single objective optimization, a multi-objective differential evolutionary algorithm, called MaximinDE, is proposed to solve this model. The experimental results based on practical production data indicate that MaximinDE can obtain a good pareto-optimal solution set, which consists of a series of alternative solutions to load distribution. Decision-makers can select a trade-off solution from the pareto-optimal solution set based on their experience or the importance of ob- iectives. In comparison with the empirical load distribution solution, the trade-off solution can achieve a better per- formance, which demonstrates the effectiveness of the multi-objective load distribution optimization. Moreover, the conflicting relationship among different objectives can be also found, which is another advantage of multi-objective load distribution optimization.
作者:
Xin CaiShaoyuan LiNing LiKang LiDepartment of Automation
Shanghai Jiao Tong University and Key Laboratory of System Control and Information Processing Ministry of Education Shanghai 200240 P. R. China School of Electronics
Electrical Engineering and Computer Science The Queen's University Belfast Belfast BT7 1NN UK
This paper addresses the problem of infinite time performance of model predictive controllers applied to constrained nonlinear systems. The total performance is compared with a finite horizon optimal cost to reveal pe...
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This paper addresses the problem of infinite time performance of model predictive controllers applied to constrained nonlinear systems. The total performance is compared with a finite horizon optimal cost to reveal performance limits of closed-loop model predictive controlsystems. Based on the Principle of Optimality, an upper and a lower bound of the ratio between the total performance and the finite horizon optimal cost are obtained explicitly expressed by the optimization horizon. The results also illustrate, from viewpoint of performance, how model predictive controllers approaches to infinite optimal controllers as the optimization horizon increases.
With the rapid growth of wind energy installed capacity, optimized maintenance has gained increasingly attentions from both researchers and wind farm owners. Condition-based maintenance (CBM) has been introduced to th...
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With the rapid growth of wind energy installed capacity, optimized maintenance has gained increasingly attentions from both researchers and wind farm owners. Condition-based maintenance (CBM) has been introduced to the wind energy industry in order to ensure the availability and safety of the wind energy conversion (WEC) system, while minimize the operating and maintenance (O&M) costs. In this paper a maintenance decision support system is introduced. By combining the information delivered by the data-driven WEC condition monitoring system and the economical benefits of each possible corrective maintenance action, the decision support system provides the operators with a choice of the most proper maintenance action for the current situation. The performance of the decision support system is tested with data collected from different WECs in a wind farm.
To improve design quality and efficiency of turbine blade, the geometric model of blade is parameterized by using the quintic polynomial method in this paper. The geometric shape and performance of blade mainly depend...
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To improve design quality and efficiency of turbine blade, the geometric model of blade is parameterized by using the quintic polynomial method in this paper. The geometric shape and performance of blade mainly depend on blade profile and cascade with parametric model. First of all, the blade profile lines are designed and generated in different parameters based on the theory of quintic polynomial. The effect of relative parameters on the blade profile is analysed conveniently and rapidly. Then, the geometric shape of blade is generated in the arranged blade profiles according to blade cascade position and consistency. The 3D model of blade is created by the parametric blade profile and cascade. It is shown that parametric model of blade will provide the reference and foundation for application research.
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