In network service systems, satisfying quality of service (QoS) is one of the main objectives. Admission control and resource allocation strategy can be used to guarantee the QoS requirement. Based on partially observ...
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In network service systems, satisfying quality of service (QoS) is one of the main objectives. Admission control and resource allocation strategy can be used to guarantee the QoS requirement. Based on partially observable Markov decision processes (POMDPs), this paper proposes a novel admission control model for video on demand (VOD) service systems with elastic QoS. Elastic QoS is also considered in resource allocation strategy. Policy gradient algorithm is often available to find the solution of POMDP problems, with a satisfactory convergence rate. Through numerical examples, it can be shown that the proposed admission control strategy has better performance than complete admission control strategy.
As an application of the Internet of Things, the connected vehicle system (CVS) plays an important role in smart city. While the vehicles in a CVS inevitably suffer with environmental noise interference, which affect ...
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As an application of the Internet of Things, the connected vehicle system (CVS) plays an important role in smart city. While the vehicles in a CVS inevitably suffer with environmental noise interference, which affect the stability of the whole system. So in this paper, the consensus of autonomous CVS is researched in the presence of stochastic multiplicative noise. The parameter restriction method is first proposed which achieves the control requirements by restricting the parameters of the designed control protocol. Then we optimize this method so that it can resist the noise with slightly larger intensity. However, this method has limited ability to resist noise of large intensity. Next we propose another method that is called the interaction network-based method, which can ensure the convergence of the system through introducing a virtual system that interacts with the original CVS. By selecting parameters of the interaction network properly, such method has a good performance in resisting larger intensity noise. In the mentioned two methods, the convergent results are derived to ensure the stability of the platoon by using the stochastic differential equation(SDE). Finally, the validity of the proposed methods is verified in the designed simulations.
In this paper, a vision-based adaptive control is designed for a wheeled inverted pendulum (WIP) robot to track a moving human target by integration of multisensor data. A new algorithm is employed in the system to co...
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In this paper, a vision-based adaptive control is designed for a wheeled inverted pendulum (WIP) robot to track a moving human target by integration of multisensor data. A new algorithm is employed in the system to combine an OptiTrack camera and a Kinect camera, such that more robust and efficient performance can be achieved for human target detection and tracking. Robust adaptive control has been developed for the WIP robot to maintain its balance on two wheels and to follow the human target using visual feedback. Leader-follower control, dynamic balance control and visual tracking are efficiently combined together to achieved desired tracking and balancing performance. Extensive experiment studies have been performed to test the effectiveness of the proposed control strategies.
This study focuses on the output feedback guaranteed cost control issue for networked controlsystems with random packet dropouts and time delays. The plant considered in this study is characterized by an uncertain li...
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This study focuses on the output feedback guaranteed cost control issue for networked controlsystems with random packet dropouts and time delays. The plant considered in this study is characterized by an uncertain linear discrete-time system, wherein random packet dropouts and time delays exist in forward controller-to-actuator and feedback sensor-to-controller communication links that are modeled as unified multiple Markov chains. The resulting closed-loop system is modeled as a Markovian jump linear system. The guaranteed cost control issue is solved via Lyapunov stability theory and the linear matrix inequality approach. The design of the mode-independent robust output feedback controller is derived under the Markov jump unified framework. The closed-loop system is not only stochastically stable but it also guarantees an adequate level of performance. A simulation example illustrates the effectiveness of the proposed method.
Wireless sensor networks on mountain roads will form winding and long transmission paths and accordingly result in centralized energy dissipation near the sink and large transmission delay. In this letter, we propose ...
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Wireless sensor networks on mountain roads will form winding and long transmission paths and accordingly result in centralized energy dissipation near the sink and large transmission delay. In this letter, we propose a node deployment scheme to settle the above-mentioned thorny issues. The core idea is to construct extra paths to the sink and achieve data diversion. Specifically, the places with relatively large transmission hops to the sink and also comparatively small distance away from it are selected as the starting points of the extra paths. This selection mechanism contributes to alleviating the energy holes and reducing the transmission delay. Finally, experimental simulations show the effectiveness and superiority of our deployment scheme.
Time delay is an inevitably negative factor to real-time vehicle control. This paper investigates cooperative spacing control of vehicle platoons with input delays under no communication between vehicles (including th...
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Time delay is an inevitably negative factor to real-time vehicle control. This paper investigates cooperative spacing control of vehicle platoons with input delays under no communication between vehicles (including the lead vehicle). The spacing control strategy is based solely on self information and onboard measurement of the immediate neighbor vehicles (preceding and succeeding vehicles). Considering the delay constraints, sufficient stability conditions are derived for the vehicle system with input delays. To avoid transient spacing errors to amplify along the string of vehicles, we give conditions that guarantee string stability of the vehicular platoon, by which the upper bound of tolerable delays are derived in terms of controller parameters and the model parameters. An algorithm is then given to determine the controller parameters using the stability and string stability conditions simultaneously. Simulations illustrate the effectiveness and the advantages of the proposed control methodology.
This paper investigates the consensus problems of the third-order discrete-time Connected Vehicle systems (CVSs) under cyber-attacks. First, the necessary and sufficient conditions for consensus of third-order discret...
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This paper investigates the consensus problems of the third-order discrete-time Connected Vehicle systems (CVSs) under cyber-attacks. First, the necessary and sufficient conditions for consensus of third-order discrete-time CVSs are derived in the absence of attacks by using algebraic graph and matrix theory. Then the interaction network framework between the original CVSs in the vehicle platoon layer and a virtual system in the hidden layer is established to resist cyber-attacks. Since sufficiently large attacks can be excluded from CVSs through a threshold defense mechanism, such potential attacks considered are bounded and generated by any linear or non-linear finite L2-gain exogenous dynamics system. It is proved that the stability of CVSs can be ensured and the state errors converge to a bounded range whether the attacks exist only in the vehicle platoon layer or in the overall systems (including the vehicle platoon layer and the hidden layer) by using the Lyapunov stability method. Finally, a simulation example containing several scenarios demonstrates the effectiveness and superiority of the proposed methods.
This paper is concerned with the distributed Kalman filtering over the wireless sensor networks (WSNs) in the presence of intermittent observations and different sensing states, where only task nodes are required to e...
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This paper is concerned with the distributed Kalman filtering over the wireless sensor networks (WSNs) in the presence of intermittent observations and different sensing states, where only task nodes are required to estimate the state of a linear time-invariant discrete-time system. A class of flexible binary values is used to develop the adaptability of flexible optimal Kalman filtering (FOKF) for variable sensing states. Based on the minimum error covariance trace principle, two classes of FOKFs have optimal collaborative estimation via their own and community observations, including the original FOKF and the FOKF with uncertain noise variance. The performance analysis of these two types of filters show that they have high estimation accuracy, strong robustness, low energy consumption and user-friendliness. The proposed algorithms are applied to estimate and track the position of a moving target in WSNs. The simulation illustrates that the proposed filters have superior performance, compared with the existing algorithms. (c) 2021 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
Benefitting from the maturation of Wireless Power Transfer technology, Wireless Rechargeable Sensor networks have become a promising solution for prolonging network lifetime. In practical charging scenarios, obstacles...
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Benefitting from the maturation of Wireless Power Transfer technology, Wireless Rechargeable Sensor networks have become a promising solution for prolonging network lifetime. In practical charging scenarios, obstacles are ubiquitous. However, most prior arts have failed to consider the combined impacts of the material, size, and location of obstacles on the charging performance, making these schemes unsuitable for real applications. In this article, we study a fundamental issue of Wireless chArger placement wIth obsTacles (WAIT), that is, how to place wireless chargers by comprehensively considering these parameters of obstacles, such that the overall charging utility is maximized. To tackle theWAIT problem, we first build a practical charging model with obstacles by introducing shadow fading, and conduct experiments to verify its correctness. Then, we design a piecewise constant function to approximate the nonlinear charging power. Afterwards, we develop a Dominating Coverage Set extraction algorithm to reduce the continuous solution space to a limited number. Finally, we prove the WAIT problem is a maximizing monotone submodular function problem, and propose a 1- 1/e - epsilon approximation algorithm to address it. Extensive simulations and field experiments show that our scheme outperforms comparison algorithms by at least 20.6% in charging utility improvement.
With wider application of P2P-based Media Delivery network (P2P-based MDN), much work has been done to improve the system' performance and efficiency in the process of media contents sharing. In this paper, we fir...
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ISBN:
(纸本)9787894631046
With wider application of P2P-based Media Delivery network (P2P-based MDN), much work has been done to improve the system' performance and efficiency in the process of media contents sharing. In this paper, we first propose a specific partially observable Markov Decision Process (POMDP) model for admission control of P2P-based MDN. Based on this model, we provide the observation-based randomized policy to conduct admission control and optimize the policy by applying policy-gradient algorithm. Observation-based policy can promote the system's performance in real time aspect and policy optimizing can increase the accuracy of controller's judgments based on partial information. Admission strategy in the paper can save the cost in operating the system for media service providers. Bandwidth allocation policy is designed to reduce service delay and provide high-quality service. The comparison results of system's performances under different policies indicate that, partial service can utilize the system's resource in a better way.
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