When the number of video group call users increases dramatically, existing TEAR algorithm cannot adjust congestion windows in time, causing network congestion, and its congestion window control does not meet the MCVid...
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ISBN:
(数字)9781728161068
ISBN:
(纸本)9781728161075
When the number of video group call users increases dramatically, existing TEAR algorithm cannot adjust congestion windows in time, causing network congestion, and its congestion window control does not meet the MCVideo system control level requirements. Aiming to solve the uncertainty about the number of users of MCVideo system video group calls, the paper proposes an adaptive MCVideo system video stream congestion window control algorithm. This algorithm uses an additive logarithmic growth factor in the congestion avoidance phase to control the congestion window of the video stream, thereby automatically adjusting the congestion window of the video stream according to the number of users to avoid network congestion. Theoretical analysis and experimental results show that the algorithm has higher throughput and lower packet loss rates than the TEAR algorithm.
This paper introduces a strategy for satisfying basic control objectives for systems whose dynamics are almost entirely unknown. This setting is motivated by a scenario where a system undergoes a critical failure, thu...
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ISBN:
(纸本)9781538679012;9781538679265
This paper introduces a strategy for satisfying basic control objectives for systems whose dynamics are almost entirely unknown. This setting is motivated by a scenario where a system undergoes a critical failure, thus significantly changing its dynamics. In such a case, retaining the ability to satisfy basic control objectives such as reach-avoid is imperative. To deal with significant restrictions on our knowledge of system dynamics, we develop a theory of myopic control. The primary goal of myopic control is to, at any given time, optimize the current direction of the system trajectory, given solely the limited information obtained about the system until that time. Building upon this notion, we propose a control algorithm which simultaneously uses small perturbations in the control effort to learn local system dynamics while moving in the direction which seems to be optimal based on previously obtained knowledge. We show that the algorithm results in a trajectory that is nearly optimal in the myopic sense, i.e., it is moving in a direction that seems to be nearly the best at the given time, and provide formal bounds for suboptimality. We demonstrate the usefulness of the proposed algorithm on a high-fidelity simulation of a damaged Boeing 747 seeking to remain in level flight.
Aiming at the problems of poor adaptability of the UAV during air combat and unreasonable decision-making mode, an optimal air combat decision-making method based on target trajectory prediction is proposed. Firstly, ...
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ISBN:
(纸本)9781728152103
Aiming at the problems of poor adaptability of the UAV during air combat and unreasonable decision-making mode, an optimal air combat decision-making method based on target trajectory prediction is proposed. Firstly, according to the non-empty air combat situation, different performance index functions are set, and then the target trajectory prediction is used to identify the enemy's intentions. According to the real-time situation analysis results, different performance index functions are selected to perform optimal control solution. Compared with other traditional methods, this method adopts the optimal control algorithm, and each maneuver made by the drone is optimal, which greatly improves the combat capability of the drone.
In this paper, we propose the connected cruise control (CCC) algorithm by analyzing human driver behavior, based on which a dynamic model is established for intelligent and connected vehicle (ICV). Changing values of ...
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ISBN:
(纸本)9781728137933
In this paper, we propose the connected cruise control (CCC) algorithm by analyzing human driver behavior, based on which a dynamic model is established for intelligent and connected vehicle (ICV). Changing values of model parameters, the CCC vehicle and the human-driven vehicle can be represented at the same time in this unified model. As a result, while ensuring the string stability of the platoon, the CCC algorithm does not require the same model parameters and control algorithms for the members of the platoon as comparative of the cooperative adaptive cruise control (CACC) algorithm, which improves its practicality under the real road conditions. A Lyapunov equation is used to verify the stability of the CCC vehicle and the string stability of the CCC platoon is verified in the two-predecessors following condition, while stability constraints on the model parameters are also given. Simulations are performed to verify the stability of dynamic models and the string stability of CCC platoon for different parameters.
The transient modes play an important role at operations of the “heating - straining” process line. These include starting the process line after planned or emergency stops and changing the work pace of the hot stra...
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ISBN:
(纸本)9781728167015
The transient modes play an important role at operations of the “heating - straining” process line. These include starting the process line after planned or emergency stops and changing the work pace of the hot straining equipment. An important task of the induction heating control during transient modes is the search for the optimal operation mode of the heating line, which ensures minimal total losses when the heater reaches a steady state. The present article solves the problem of minimizing energy consumption during the transition of a continuous two-section induction heater to a steady state mode. The design of optimal control algorithms in transient modes is based on the electrothermal model, taking into account the nonlinear relationship of the distribution of the specific heating power in each section with the temperature distribution along the radial and axial coordinates. It is shown that temperature deviations, which occur during the transient modes of continuous heaters can significantly exceeds the limits of technological tolerances. Under these conditions, the optimal control search problem is to determine the algorithms for changing the power of each section and the moment when the billet starts to move through the heater. The obtained algorithms provide the minimum balance delay of straining equipment and the minimum unproductive waste energy for heating substandard billets. The paper estimates the control algorithms effectiveness for the starting mode from the “cold” state and from the “thermostatic temperature control” mode. Some variants of energy efficient start-up control algorithms are proposed, which depend on the specific conditions of the technological process and requirements for process quality indicators.
Internet applications are increasing network traffic exponentially these days due to remarkable growth of the Internet. To handle the huge traffic on Transport Layer one provides the most trusted, Connection oriented ...
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ISBN:
(纸本)9781728100012
Internet applications are increasing network traffic exponentially these days due to remarkable growth of the Internet. To handle the huge traffic on Transport Layer one provides the most trusted, Connection oriented and end-to-end packet delivery protocol which is Transmission Control Protocol (TCP). There are many problems available in congestion control algorithms i.e. transfer size of the packet, initialization of Congestion Window, cross traffic, congestion along the path, size of the router buffer, intra protocol and inter protocol fairness. There are many variants of the protocol available to control the congestion. This paper presents a comparative analysis of commonly used TCP flavors. We present analysis of TCP protocol named, TCP Reno, CUBIC-TCP, FAST-FIT, TCP New Reno and followed by experiment results.
The bidirectional DC-DC converters (BDC) is extensively promoted for numerous applications. Dual-active-bridge (DAB) converter is preferred among all other BDC converters for medium and high power application. There a...
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ISBN:
(纸本)9781728104201
The bidirectional DC-DC converters (BDC) is extensively promoted for numerous applications. Dual-active-bridge (DAB) converter is preferred among all other BDC converters for medium and high power application. There are some key challenges of isolated boost based BDC converters. Isolated boost based BDC converters offer high voltage spike, high current stress, and additional conduction losses due to flowing the freewheeling current in the switches of the low-voltage-side bridge of DAB converter. The auxiliary clamping circuits have been required to mitigate freewheeling current. The BDC converter with dual-switch forward (DSF) snubber has been presented in this paper. The converter operation of the BDC converter has been discussed. The various auxiliary clamping circuits have been explained. The control algorithm of the BDC DSF snubber circuit has been conferred. The comparative analysis has been considered among all BDC converters with the auxiliary clamping circuits. The PSIM simulation tool has been chosen to verify the effectiveness of the converter in the closed-loop control of the converter. The simulation results show the effectiveness of the converter.
Distributed energy resources (DERs) are becoming an important part of distribution systems, because of their economic and environmental benefits. Although their inherent intermittency and volatility introduce uncertai...
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ISBN:
(纸本)9781538679012;9781538679265
Distributed energy resources (DERs) are becoming an important part of distribution systems, because of their economic and environmental benefits. Although their inherent intermittency and volatility introduce uncertainties into the electric power system, they have the potential to provide controllability to the system under proper coordination. In this paper, we propose a hierarchical control algorithm for distribution systems with DERs so that they have controllability similar to a generator bus. The upper level scheduler solves a chance-constrained optimal power flow (OPF) problem to plan the operation of the DERs based on forecasts, and the lower level distributed DER controllers leverage the extremum seeking approach to deliver the planned power at the feeder head. The proposed algorithm is tested on a modified IEEE 13-node feeder, demonstrating its effectiveness.
One of the key aspects in racing is the ability of the driver to find the handling limits of the vehicle to minimize the resulting lap time. Many approaches for raceline optimization assume the tire-road friction coef...
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ISBN:
(纸本)9781728101439
One of the key aspects in racing is the ability of the driver to find the handling limits of the vehicle to minimize the resulting lap time. Many approaches for raceline optimization assume the tire-road friction coefficient to be known. However, this neglects the fact that the ability of the system to realize such a race trajectory depends on complex interdependencies between the online trajectory planner, the control systems and the non-modelled uncertainties. In general, a high quality control system can approach the physical limit more reliable, as it applies less corrective actions. We present a model-free learning method to find the minimum achievable lap-time for a given controller using online adaption of a scale factor for the maximum longitudinal and lateral accelerations in the online trajectory planner. In contrast to existing concepts, our approach can be applied as an extension to already available planning and control algorithms instead of replacing them. We demonstrate reliable and safe operation for different vehicle setups in simulation and demonstrate that the algorithm works successfully on a full-size racecar.
This paper proposes a selective control algorithm to reduce switching losses of N-phase switching pole of 3-phase 4-leg interlinking converter (ILC) in AC/DC hybrid microgrid. Unbalanced load connected to 3-phase 4-le...
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ISBN:
(纸本)9781728133997
This paper proposes a selective control algorithm to reduce switching losses of N-phase switching pole of 3-phase 4-leg interlinking converter (ILC) in AC/DC hybrid microgrid. Unbalanced load connected to 3-phase 4-leg ILC causes unbalanced voltage condition and this problems can be complemented by N-phase switching pole of 4-leg ILC. However, if the switching pole on N is operated constantly regardless of control decision due to unbalanced load conditions, switching loss on the N-phase switching pole will cause power loss in the entire topology. To compensate this problem, selective control algorithm considering voltage unbalance factor (VUF) for N-phase switching pole in ILC is proposed. Proposed algorithm decides switching operation of N-phase switching pole depending on unbalanced load voltage. When occurring unbalanced load condition, voltage unbalance factor can be reduced by proposed control algorithm. At the same time, the current flowing through the N-phase switch pole and switching losses can be reduced.
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