Owing to the ubiquity of wireless networks and the popularity of WiFi infrastructures,received signal strength(RSS)-based indoor localization systems have received much attention.The placement of access points(APs)sig...Owing to the ubiquity of wireless networks and the popularity of WiFi infrastructures,received signal strength(RSS)-based indoor localization systems have received much attention.The placement of access points(APs)significantly influences localization accuracy and network access.However,the indoor scenario and network access are not fully considered in previous AP placement optimization methods.This study proposes a practical scenario modelingaided AP placement optimization method for improving localization accuracy and network access.In order to reduce the gap between simulation-based and field measurement-based AP placement optimization methods,we introduce an indoor scenario modeling and Gaussian process-based RSS prediction method.After that,the localization and network access metrics are implemented in the multiple objective particle swarm optimization(MOPSO)solution,Pareto front criterion and virtual repulsion force are applied to determine the optimal AP placement.Finally,field experiments demonstrate the effectiveness of the proposed indoor scenario modeling method and RSS prediction model.A thorough comparison confirms the localization and network access improvement attributed to the proposed anchor placement method.展开更多
Real-time prediction of excavation-induced displacement of retaining pile during the deep excavation process is crucial for construction safety.This paper proposes a modified back analysis method with multi-objective ...Real-time prediction of excavation-induced displacement of retaining pile during the deep excavation process is crucial for construction safety.This paper proposes a modified back analysis method with multi-objective optimization procedure,which enables a real-time prediction of horizontal displacement of retaining pile during construction.As opposed to the traditional stage-by-stage back analysis,time series monitoring data till the current excavation stage are utilized to form a multi-objective function.Then,the multi-objective particle swarm optimization (MOPSO) algorithm is applied for parameter identification.The optimized model parameters are immediately adopted to predict the excavation-induced pile deformation in the continuous construction stages.To achieve efficient parameter optimization and real-time prediction of system behavior,the back propagation neural network (BPNN) is established to substitute the finite element model,which is further implemented together with MOPSO for automatic operation.The proposed approach is applied in the Taihu tunnel excavation project,where the effectiveness of the method is demonstrated via the comparisons with the site monitoring data.The method is reliable with a prediction accuracy of more than 90%.Moreover,different optimization algorithms,including non-dominated sorting genetic algorithm (NSGA-II),Pareto Envelope-based Selection Algorithm II (PESA-II) and MOPSO,are compared,and their influences on the prediction accuracy at different excavation stages are studied.The results show that MOPSO has the best performance for high dimensional optimization task.展开更多
侦察星座优化是天基信息体系建设的关键问题。为弥补以往研究大多只采用少量性能指标进行侦察星座优化的不足,提出了一种综合考虑5项性能指标的侦察星座优化模型。在解算优化模型过程中,为解决传统基于Pareto支配的进化算法出现的选择...侦察星座优化是天基信息体系建设的关键问题。为弥补以往研究大多只采用少量性能指标进行侦察星座优化的不足,提出了一种综合考虑5项性能指标的侦察星座优化模型。在解算优化模型过程中,为解决传统基于Pareto支配的进化算法出现的选择压力与多样性不足的问题,提出了TOPSIS-MOPSO(Technique for Order Preference by Similarity to an Ideal Solution-Multi-Objective Particle Swarm Optimization)算法,将多属性决策领域的TOPSIS引入进化算法中,并与SPD(Strengthened Pareto Dominate)相结合,得到一种能够同时增强种群收敛性与多样性的环境选择策略。提出了基于Harmonic距离的全局最优粒子选择策略,加快种群收敛速度,保护种群多样性;提出了自适应进化算子选择策略,帮助算法摆脱局部最优解。将TOPSIS-MOPSO算法应用在侦察星座优化问题上,并与MOPSO、DGEA、AR-MOEA 3种经典方法进行实验对比分析,实验结果显示,所提算法比其他3种算法在Δ*、IGD和HV上的最优指标值分别提升了19.76%、89.07%和28.2%。展开更多
文摘Owing to the ubiquity of wireless networks and the popularity of WiFi infrastructures,received signal strength(RSS)-based indoor localization systems have received much attention.The placement of access points(APs)significantly influences localization accuracy and network access.However,the indoor scenario and network access are not fully considered in previous AP placement optimization methods.This study proposes a practical scenario modelingaided AP placement optimization method for improving localization accuracy and network access.In order to reduce the gap between simulation-based and field measurement-based AP placement optimization methods,we introduce an indoor scenario modeling and Gaussian process-based RSS prediction method.After that,the localization and network access metrics are implemented in the multiple objective particle swarm optimization(MOPSO)solution,Pareto front criterion and virtual repulsion force are applied to determine the optimal AP placement.Finally,field experiments demonstrate the effectiveness of the proposed indoor scenario modeling method and RSS prediction model.A thorough comparison confirms the localization and network access improvement attributed to the proposed anchor placement method.
基金supported by the National Natural Science Foundation of China(Grant Nos.52208380 and 51979270)the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(Grant No.SKLGME021022).
文摘Real-time prediction of excavation-induced displacement of retaining pile during the deep excavation process is crucial for construction safety.This paper proposes a modified back analysis method with multi-objective optimization procedure,which enables a real-time prediction of horizontal displacement of retaining pile during construction.As opposed to the traditional stage-by-stage back analysis,time series monitoring data till the current excavation stage are utilized to form a multi-objective function.Then,the multi-objective particle swarm optimization (MOPSO) algorithm is applied for parameter identification.The optimized model parameters are immediately adopted to predict the excavation-induced pile deformation in the continuous construction stages.To achieve efficient parameter optimization and real-time prediction of system behavior,the back propagation neural network (BPNN) is established to substitute the finite element model,which is further implemented together with MOPSO for automatic operation.The proposed approach is applied in the Taihu tunnel excavation project,where the effectiveness of the method is demonstrated via the comparisons with the site monitoring data.The method is reliable with a prediction accuracy of more than 90%.Moreover,different optimization algorithms,including non-dominated sorting genetic algorithm (NSGA-II),Pareto Envelope-based Selection Algorithm II (PESA-II) and MOPSO,are compared,and their influences on the prediction accuracy at different excavation stages are studied.The results show that MOPSO has the best performance for high dimensional optimization task.
文摘侦察星座优化是天基信息体系建设的关键问题。为弥补以往研究大多只采用少量性能指标进行侦察星座优化的不足,提出了一种综合考虑5项性能指标的侦察星座优化模型。在解算优化模型过程中,为解决传统基于Pareto支配的进化算法出现的选择压力与多样性不足的问题,提出了TOPSIS-MOPSO(Technique for Order Preference by Similarity to an Ideal Solution-Multi-Objective Particle Swarm Optimization)算法,将多属性决策领域的TOPSIS引入进化算法中,并与SPD(Strengthened Pareto Dominate)相结合,得到一种能够同时增强种群收敛性与多样性的环境选择策略。提出了基于Harmonic距离的全局最优粒子选择策略,加快种群收敛速度,保护种群多样性;提出了自适应进化算子选择策略,帮助算法摆脱局部最优解。将TOPSIS-MOPSO算法应用在侦察星座优化问题上,并与MOPSO、DGEA、AR-MOEA 3种经典方法进行实验对比分析,实验结果显示,所提算法比其他3种算法在Δ*、IGD和HV上的最优指标值分别提升了19.76%、89.07%和28.2%。
