期刊文献+
共找到3,310篇文章
< 1 2 166 >
每页显示 20 50 100
Multi-Time Scale Optimal Scheduling of a Photovoltaic Energy Storage Building System Based on Model Predictive Control
1
作者 Ximin Cao Xinglong Chen +2 位作者 He Huang Yanchi Zhang Qifan Huang 《Energy Engineering》 EI 2024年第4期1067-1089,共23页
Building emission reduction is an important way to achieve China’s carbon peaking and carbon neutrality goals.Aiming at the problem of low carbon economic operation of a photovoltaic energy storage building system,a ... Building emission reduction is an important way to achieve China’s carbon peaking and carbon neutrality goals.Aiming at the problem of low carbon economic operation of a photovoltaic energy storage building system,a multi-time scale optimal scheduling strategy based on model predictive control(MPC)is proposed under the consideration of load optimization.First,load optimization is achieved by controlling the charging time of electric vehicles as well as adjusting the air conditioning operation temperature,and the photovoltaic energy storage building system model is constructed to propose a day-ahead scheduling strategy with the lowest daily operation cost.Second,considering inter-day to intra-day source-load prediction error,an intraday rolling optimal scheduling strategy based on MPC is proposed that dynamically corrects the day-ahead dispatch results to stabilize system power fluctuations and promote photovoltaic consumption.Finally,taking an office building on a summer work day as an example,the effectiveness of the proposed scheduling strategy is verified.The results of the example show that the strategy reduces the total operating cost of the photovoltaic energy storage building system by 17.11%,improves the carbon emission reduction by 7.99%,and the photovoltaic consumption rate reaches 98.57%,improving the system’s low-carbon and economic performance. 展开更多
关键词 Load optimization model predictive control multi-time scale optimal scheduling photovoltaic consumption photovoltaic energy storage building
下载PDF
Integrated strategy for real-time wind power fluctuation mitigation and energy storage system control
2
作者 Yu Zhang Yongkang Zhang Tiezhou Wu 《Global Energy Interconnection》 EI CSCD 2024年第1期71-81,共11页
To address the impact of wind-power fluctuations on the stability of power systems,we propose a comprehensive approach that integrates multiple strategies and methods to enhance the efficiency and reliability of a sys... To address the impact of wind-power fluctuations on the stability of power systems,we propose a comprehensive approach that integrates multiple strategies and methods to enhance the efficiency and reliability of a system.First,we employ a strategy that restricts long-and short-term power output deviations to smoothen wind power fluctuations in real time.Second,we adopt the sliding window instantaneous complete ensemble empirical mode decomposition with adaptive noise(SW-ICEEMDAN)strategy to achieve real-time decomposition of the energy storage power,facilitating internal power distribution within the hybrid energy storage system.Finally,we introduce a rule-based multi-fuzzy control strategy for the secondary adjustment of the initial power allocation commands for different energy storage components.Through simulation validation,we demonstrate that the proposed comprehensive control strategy can smoothen wind power fluctuations in real time and decompose energy storage power.Compared with traditional empirical mode decomposition(EMD),ensemble empirical mode decomposition(EEMD),and complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)decomposition strategies,the configuration of the energy storage system under the SW-ICEEMDAN control strategy is more optimal.Additionally,the state-of-charge of energy storage components fluctuates within a reasonable range,enhancing the stability of the power system and ensuring the secure operation of the energy storage system. 展开更多
关键词 SW-ICEEMDAN HESS real-time smoothing Rule-based multi-fuzzy control SoC
下载PDF
Two-Stage Optimal Scheduling of Community Integrated Energy System
3
作者 Ming Li Rifucairen Fu +4 位作者 Tuerhong Yaxiaer Yunping Zheng Abiao Huang Ronghui Liu Shunfu Lin 《Energy Engineering》 EI 2024年第2期405-424,共20页
From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling an... From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling analyzes whether various controllable loads participate in the optimization and investigates the impact of their responses on the operating economy of the community integrated energy system(IES)before and after;the intra-day scheduling proposes a two-stage rolling optimization model based on the day-ahead scheduling scheme,taking into account the fluctuation of wind turbine output and load within a short period of time and according to the different response rates of heat and cooling power,and solves the adjusted output of each controllable device.The simulation results show that the optimal scheduling of controllable loads effectively reduces the comprehensive operating costs of community IES;the two-stage optimal scheduling model can meet the energy demand of customers while effectively and timely suppressing the random fluctuations on both sides of the source and load during the intra-day stage,realizing the economic and smooth operation of IES. 展开更多
关键词 Integrated energy system two-stage optimal scheduling controllable loads rolling optimization
下载PDF
A Model Predictive Scheduling Algorithm inReal-Time Control Systems 被引量:2
4
作者 Mengya Kang Chenglin Wen Chenxi Wu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第2期471-478,共8页
Abstract-The ineffective utilization of power resources has attracted much attention in current years. This paper proposes a real-time distributed load scheduling algorithm considering constraints of power supply. Fir... Abstract-The ineffective utilization of power resources has attracted much attention in current years. This paper proposes a real-time distributed load scheduling algorithm considering constraints of power supply. Firstly, an objective function is designed based on the constraint, and a base load forecasting model is established when aggregating renewable generation and non-deferrable load into a power system, which aims to transform the problem of deferrable loads scheduling into a distributed optimal control problem. Then, to optimize the objective function, a real-time scheduling algorithm is presented to solve the proposed control problem. At every time step, the purpose is to minimize the variance of differences between power supply and aggregate load, which can thus ensure the effective utilization of power resources. Finally, simulation examples are provided to illustrate the effectiveness of the proposed algorithm. 展开更多
关键词 Index Terms-Deferrable loads scheduling electric vehicles(EVs) optimal control power supply real-time distributed con-trol.
下载PDF
Application of predictive control scheduling method to real-time periodic control tasks overrun 被引量:1
5
作者 沈青 桂卫华 +1 位作者 阳春华 杨铁军 《Journal of Central South University of Technology》 EI 2007年第2期266-270,共5页
Based on the abort strategy of fixed periods, a novel predictive control scheduling methodology was proposed to efficiently solve overrun problems. By applying the latest control value in the prediction sequences to t... Based on the abort strategy of fixed periods, a novel predictive control scheduling methodology was proposed to efficiently solve overrun problems. By applying the latest control value in the prediction sequences to the control objective, the new strategy was expected to optimize the control system for better performance and yet guarantee the schedulability of all tasks under overrun. The schedulability of the real-time systems with p-period overruns was analyzed, and the corresponding stability criteria was given as well. The simulation results show that the new approach can improve the performance of control system compared to that of conventional abort strategy, it can reduce the overshoot and adjust time as well as ensure the schedulability and stability. 展开更多
关键词 real-time system OVERRUN predictive control scheduling STABILITY
下载PDF
FEL-H Robust Control Real-Time Scheduling 被引量:1
6
作者 Bing Du Chun Ruan 《Journal of Software Engineering and Applications》 2009年第1期60-65,共6页
The existing scheduling algorithms cannot adequately support modern embedded real-time applications. An important challenge for future research is how to model and introduce control mechanisms to real-time systems to ... The existing scheduling algorithms cannot adequately support modern embedded real-time applications. An important challenge for future research is how to model and introduce control mechanisms to real-time systems to improve real-time performance, and to allow the system to adapt to changes in the environment, the workload, or to changes in the system architecture due to failures. In this paper, we pursue this goal by formulating and simulating new real-time scheduling models that enable us to easily analyse feedback scheduling with various constraints, overload and disturbance, and by designing a robust, adaptive scheduler that responds gracefully to overload with robust H∞ and feedback error learning control. 展开更多
关键词 ROBUST real-timE scheduling Feedbacke Simulation FEEDBACK
下载PDF
Long-release-interval-first real-time scheduling algorithm and its schedulability test
7
作者 沈卓炜 汪芸 《Journal of Southeast University(English Edition)》 EI CAS 2006年第4期484-489,共6页
To fulfill the requirements for hybrid real-time system scheduling, a long-release-interval-first (LRIF) real-time scheduling algorithm is proposed. The algorithm adopts both the fixed priority and the dynamic prior... To fulfill the requirements for hybrid real-time system scheduling, a long-release-interval-first (LRIF) real-time scheduling algorithm is proposed. The algorithm adopts both the fixed priority and the dynamic priority to assign priorities for tasks. By assigning higher priorities to the aperiodic soft real-time jobs with longer release intervals, it guarantees the executions for periodic hard real-time tasks and further probabilistically guarantees the executions for aperiodic soft real-time tasks. The schedulability test approach for the LRIF algorithm is presented. The implementation issues of the LRIF algorithm are also discussed. Simulation result shows that LRIF obtains better schedulable performance than the maximum urgency first (MUF) algorithm, the earliest deadline first (EDF) algorithm and EDF for hybrid tasks. LRIF has great capability to schedule both periodic hard real-time and aperiodic soft real-time tasks. 展开更多
关键词 real-time scheduling schedulability test earliest deadline first maximum urgency first long release interval first
下载PDF
A non-myopic scheduling method of radar sensors for maneuvering target tracking and radiation control 被引量:15
8
作者 Gan-lin Shan Gong-guo Xu Cheng-lin Qiao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第1期242-250,共9页
In decades,the battlefield environment is becoming more and more complex with plenty of electronic equipments.Thus,in order to improve the survivability of radar sensors and satisfy the requirement of maneuvering targ... In decades,the battlefield environment is becoming more and more complex with plenty of electronic equipments.Thus,in order to improve the survivability of radar sensors and satisfy the requirement of maneuvering target tracking with a low probability of intercept,a non-myopic scheduling is proposed to minimize the radiation cost with tracking accuracy constraint.At first,the scheduling problem is formulated as a partially observable Markov decision process(POMDP).Then the tracking accuracy and radiation cost over the future finite time horizon are predicted by the posterior carmer-rao lower bound(PCRLB) and the hidden Markov model filter,respectively.Finally,the proposed scheduling is implemented efficiently by utilizing the branch and bound(B&B) pruning algorithm.Simulation results show that the performance of maneuvering target tracking was improved by the improved interacting multiple model(IMM),and the scheduler time and maximum memory consumption were significant reduced by the present B&B pruning algorithm without losing the optimal solution. 展开更多
关键词 Non-myopic scheduling RADIATION control PCRLB POMDP Branch and BOUND
下载PDF
Research on fault-tolerant control of networked control systems based on information scheduling 被引量:5
9
作者 Huo Zhihong Zhang Zhixue Fang Huajing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第5期1024-1028,共5页
A kind of networked control system is studied; the networked control system with noise disturbance is modeled based on information scheduling and control co-design. Augmented state matrix analysis method is introduced... A kind of networked control system is studied; the networked control system with noise disturbance is modeled based on information scheduling and control co-design. Augmented state matrix analysis method is introduced, and robust fault-tolerant control problem of networked control systems with noise disturbance under actuator failures is studied. The parametric expression of the controller under actuator failures is given. Furthermore, the result is analyzed by simulation tests, which not only satisfies the networked control systems stability, but also decreases the data information number in network channel and makes full use of the network resources. 展开更多
关键词 networked control systems fault-tolerant control information scheduling linear matrix inequality.
下载PDF
Feedback Scheduling of Model-based Networked Control Systems with Flexible Workload 被引量:4
10
作者 Xian-Ming Tang Jin-Shou Yu 《International Journal of Automation and computing》 EI 2008年第4期389-394,共6页
In this paper,a novel control structure called feedback scheduling of model-based networked control systems is proposed to cope with a flexible network load and resource constraints.The state update time is adjusted a... In this paper,a novel control structure called feedback scheduling of model-based networked control systems is proposed to cope with a flexible network load and resource constraints.The state update time is adjusted according to the real-time network congestion situation.State observer is used under the situation where the state of the controlled plant could not be acquired.The stability criterion of the proposed structure is proved with time-varying state update time.On the basis of the stability of the novel system structure,the compromise between the control performance and the network utilization is realized by using feedback scheduler. Examples are provided to show the advantage of the proposed control structure. 展开更多
关键词 Model-based networked control system state update time stability criterion feedback scheduling.
下载PDF
Improved control of intelligent excavator using proportional-integral-plus gain scheduling 被引量:5
11
作者 顾军 D. SEWARD 《Journal of Central South University》 SCIE EI CAS 2012年第2期384-392,共9页
Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to aut... Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to autonomously dig trenches without human intervention. One stumbling block is the achievement of adequate, accurate, quick and smooth movement under automatic control, which is difficult for traditional control algorithm, e.g. PI/PID. A gain scheduling design, based on the true digital proportional-integral-plus (PIP) control methodology, was utilized to regulate the nonlinear joint dynamics. Simulation and initial field tests both demonstrated the feasibility and robustness of proposed technique to the uncertainties of parameters, time delay and load disturbances, with the excavator arm directed along specified trajectories in a smooth, fast and accurate manner. The tracking error magnitudes for oblique straight line and horizontal straight line are less than 20 mm and 50 mm, respectively, while the velocity reaches 9 m/min. 展开更多
关键词 robotic excavator gain scheduling control proportional-integral-plus ROBUSTNESS
下载PDF
Real-time scheduling strategy for microgrids considering operation interval division of DGs and batteries 被引量:7
12
作者 Chunyang Liu Yinghao Qin Hengxu Zhang 《Global Energy Interconnection》 2020年第5期442-452,共11页
Real-time scheduling as an on-line optimization process must output dispatch results in real time. However, the calculation time required and the economy have a trade-off relationship. In response to a real-time sched... Real-time scheduling as an on-line optimization process must output dispatch results in real time. However, the calculation time required and the economy have a trade-off relationship. In response to a real-time scheduling problem, this paper proposes a real-time scheduling strategy considering the operation interval division of distributed generators(DGs) and batteries in the microgrid. Rolling scheduling models, including day-ahead scheduling and hours-ahead scheduling, are established, where the latter considers the future state-of-charge deviations. For the real-time scheduling, the output powers of the DGs are divided into two intervals based on the ability to track the day-ahead and hours-ahead schedules. The day-ahead and hours-ahead scheduling ensure the economy, whereas the real-time scheduling overcomes the timeconsumption problem. Finally, a grid-connected microgrid example is studied, and the simulation results demonstrate the effectiveness of the proposed strategy in terms of economic and real-time requirements. 展开更多
关键词 MICROGRID real-time scheduling Rolling scheduling Interval division
下载PDF
SWARM INTELLIGENCE BASED DYNAMIC REAL-TIME SCHEDULING APPROACH FOR SEMICONDUCTOR WAFER FAB 被引量:4
13
作者 LiLi FeiQiao WuQidi 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2005年第1期71-74,共4页
Based on the analysis of collective activities of ant colonies, the typicalexample of swarm intelligence, a new approach to construct swarm intelligence basedmulti-agent-system (SMAS) for dynamic real-time scheduling ... Based on the analysis of collective activities of ant colonies, the typicalexample of swarm intelligence, a new approach to construct swarm intelligence basedmulti-agent-system (SMAS) for dynamic real-time scheduling for semiconductor wafer fab is proposed.The relevant algorithm, pheromone-based dynamic real-time scheduling algorithm (PBDR), is given.MIMAC test bed data set mini-fab is used to compare PBDR with FIFO (first in first out),SRPT(shortest remaining processing time) and CR(critical ratio) under three different release rules,i.e. deterministic rule, Poisson rule and CONWIP (constant WIP). It is shown that PBDR is prior toFIFO, SRPT and CR with better performance of cycle time, throughput, and on-time delivery,especially for on-time delivery performance. 展开更多
关键词 Swarm intelligence Ant colonies PHEROMONE Ant agents Semiconductor waferfab Dynamic real-time scheduling
下载PDF
Multi-Agent Deep Reinforcement Learning for Cross-Layer Scheduling in Mobile Ad-Hoc Networks
14
作者 Xinxing Zheng Yu Zhao +1 位作者 Joohyun Lee Wei Chen 《China Communications》 SCIE CSCD 2023年第8期78-88,共11页
Due to the fading characteristics of wireless channels and the burstiness of data traffic,how to deal with congestion in Ad-hoc networks with effective algorithms is still open and challenging.In this paper,we focus o... Due to the fading characteristics of wireless channels and the burstiness of data traffic,how to deal with congestion in Ad-hoc networks with effective algorithms is still open and challenging.In this paper,we focus on enabling congestion control to minimize network transmission delays through flexible power control.To effectively solve the congestion problem,we propose a distributed cross-layer scheduling algorithm,which is empowered by graph-based multi-agent deep reinforcement learning.The transmit power is adaptively adjusted in real-time by our algorithm based only on local information(i.e.,channel state information and queue length)and local communication(i.e.,information exchanged with neighbors).Moreover,the training complexity of the algorithm is low due to the regional cooperation based on the graph attention network.In the evaluation,we show that our algorithm can reduce the transmission delay of data flow under severe signal interference and drastically changing channel states,and demonstrate the adaptability and stability in different topologies.The method is general and can be extended to various types of topologies. 展开更多
关键词 Ad-hoc network cross-layer scheduling multi agent deep reinforcement learning interference elimination power control queue scheduling actorcritic methods markov decision process
下载PDF
A Distributionally Robust Optimization Method for Passenger Flow Control Strategy and Train Scheduling on an Urban Rail Transit Line 被引量:4
15
作者 Yahan Lu Lixing Yang +4 位作者 Kai Yang Ziyou Gao Housheng Zhou Fanting Meng Jianguo Qi 《Engineering》 SCIE EI CAS 2022年第5期202-220,共19页
Regular coronavirus disease 2019(COVID-19)epidemic prevention and control have raised new require-ments that necessitate operation-strategy innovation in urban rail transit.To alleviate increasingly seri-ous congestio... Regular coronavirus disease 2019(COVID-19)epidemic prevention and control have raised new require-ments that necessitate operation-strategy innovation in urban rail transit.To alleviate increasingly seri-ous congestion and further reduce the risk of cross-infection,a novel two-stage distributionally robust optimization(DRO)model is explicitly constructed,in which the probability distribution of stochastic scenarios is only partially known in advance.In the proposed model,the mean-conditional value-at-risk(CVaR)criterion is employed to obtain a tradeoff between the expected number of waiting passen-gers and the risk of congestion on an urban rail transit line.The relationship between the proposed DRO model and the traditional two-stage stochastic programming(SP)model is also depicted.Furthermore,to overcome the obstacle of model solvability resulting from imprecise probability distributions,a discrepancy-based ambiguity set is used to transform the robust counterpart into its computationally tractable form.A hybrid algorithm that combines a local search algorithm with a mixed-integer linear programming(MILP)solver is developed to improve the computational efficiency of large-scale instances.Finally,a series of numerical examples with real-world operation data are executed to validate the pro-posed approaches. 展开更多
关键词 Passenger flow control Train scheduling Distributionally robust optimization Stochastic and dynamic passenger demand Ambiguity set
下载PDF
Predictive control and scheduling codesign in network control systems 被引量:1
16
作者 Qing SHEN 1 , 2 , Weihua GUI 2 , Ying XIONG 2 , Chunhua YANG 2 (1.School of Basic Education for Officers, National University of Defense Technology, Changsha Hunan 410003, China 2.School of Information Science and Engineering, Central South University, Changsha Hunan 410083, China) 《控制理论与应用(英文版)》 EI 2010年第2期239-244,共6页
A codesign approach combining predictive control compensation and network scheduling is presented in this paper to overcome the adverse influences of stochastic time delays and packet losses encountered in network-bas... A codesign approach combining predictive control compensation and network scheduling is presented in this paper to overcome the adverse influences of stochastic time delays and packet losses encountered in network-based real-time control systems. The state estimation and control prediction compensation algorithms are used for the random network delays in the feedback and forward channels, and the stability criteria are analyzed. The proper sampling rate is given with network scheduling to meet the desired system performance, while the network-induced delay is tolerated. Simulations show that the codesign approach works well with the bounded network delay. 展开更多
关键词 Network control system PREDICTION scheduling STABILITY
下载PDF
Feasibility Assessment of Fast Numerical Simulations for Real-Time Monitoring and Control of PEM Fuel Cells
17
作者 Abbas Ghasemi Samaneh Shahgaldi Xianguo Li 《Transactions of Tianjin University》 EI CAS 2023年第1期31-45,共15页
Computational models that ensure accurate and fast responses to the variations in operating conditions,such as the cell tem-perature and relative humidity(RH),are essential monitoring tools for the real-time control o... Computational models that ensure accurate and fast responses to the variations in operating conditions,such as the cell tem-perature and relative humidity(RH),are essential monitoring tools for the real-time control of proton exchange membrane(PEM)fuel cells.To this end,fast cell-area-averaged numerical simulations are developed and verifi ed against the present experiments under various RH levels.The present simulations and measurements are found to agree well based on the cell voltage(polarization curve)and power density under variable RH conditions(RH=40%,RH=70%,and RH=100%),which verifi es the model accuracy in predicting PEM fuel cell performance.In addition,computationally feasible reduced-order models are found to deliver a fast output dataset to evaluate the charge/heat/mass transfer phenomena as well as water production and two-phase fl ow transport.Such fast and accurate evaluations of the overall fuel cell operation can be used to inform the real-time control systems that allow for the improved optimization of PEM fuel cell performance. 展开更多
关键词 fuel cell Relative humidity real-time control Gas diff usion layer Catalyst layer
下载PDF
Gain Scheduling Control of Nonlinear Shock Motion Based on Equilibrium Manifold Linearization Model 被引量:1
18
作者 Cui Tao Yu Daren Bao Wen Yang Yongbin 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2007年第6期481-487,共7页
The equilibrium manifold linearization model of nonlinear shock motion is of higher accuracy and lower complexity over other models such as the small perturbation model and the piecewise-linear model. This paper analy... The equilibrium manifold linearization model of nonlinear shock motion is of higher accuracy and lower complexity over other models such as the small perturbation model and the piecewise-linear model. This paper analyzes the physical significance of the equilibrium manifold linearization model, and the self-feedback mechanism of shock motion is revealed. This helps to describe the stability and dynamics of shock motion. Based on the model, the paper puts forwards a gain scheduling control method for nonlinear shock motion. Simulation has shown the validity of the control scheme. 展开更多
关键词 shock motion equilibrium manifold linearization gain scheduling control
下载PDF
Using Adaptive Gain Scheduling LQR Method Control of Arm Driven Inverted Pendulum System Based on PIC18F4431 被引量:1
19
作者 Huu Chan Thanh Nguyen An-Wen Shen 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第4期85-92,共8页
The arm driven inverted pendulum system is a highly nonlinear model, muhivariable and absolutely unstable dynamic system so it is very difficult to obtain exact mathematical model and balance the inverted pendulum wit... The arm driven inverted pendulum system is a highly nonlinear model, muhivariable and absolutely unstable dynamic system so it is very difficult to obtain exact mathematical model and balance the inverted pendulum with variable position of the ann. To solve this problem, this paper presents a mathematical model for arm driven inverted pendulum in mid-position configuration and an adaptive gain scheduling linear quadratic regulator control method for the stabilizing the inverted pendulum. The proposed controllers for arm driven inverted pendulum are simulated using MATLAB-SIMULINK and implemented on an experiment system using PIC 18F4431 mieroeontroller. The result of experiment system shows the control performance to be very good in a wide range stabilization of the arm position. 展开更多
关键词 Arm Driven Inverted Pendulum (ADIP) adaptive gain scheduling LQR control LQR control swing up pendlum
下载PDF
Scheduling transactions in mobile distributed real-time database systems 被引量:1
20
作者 雷向东 赵跃龙 +1 位作者 陈松乔 袁晓莉 《Journal of Central South University of Technology》 EI 2008年第4期545-551,共7页
A DMVOCC-MVDA (distributed multiversion optimistic concurrency control with multiversion dynamic adjustment) protocol was presented to process mobile distributed real-time transaction in mobile broadcast environment... A DMVOCC-MVDA (distributed multiversion optimistic concurrency control with multiversion dynamic adjustment) protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load (think time is ls) the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols. 展开更多
关键词 mobile distributed real-time database systems muliversion optimistic concurrency control multiversion dynamic adjustment pre-validation multiversion data broadcast
下载PDF
上一页 1 2 166 下一页 到第
使用帮助 返回顶部