To support the rapid automatic services composition and fulfill multi-quality of service （multi- QoS） demand, we propose a novel approach to realize services composition automatically by a prefihering process. Aimed...To support the rapid automatic services composition and fulfill multi-quality of service （multi- QoS） demand, we propose a novel approach to realize services composition automatically by a prefihering process. Aimed at a set of web services with similar functionality and different quality of service （QoS） , a semantic services chain is given and a corresponding constructing algorithm is proposed to construct the data structure. A pre-filtering process is put forward to find whether a composition service before planning exists. It can avoid aborted planning. An optimal planning algorithm is proposed which can choose the most suitable service from a lot of similar candidate services based on semantic service chains and multi-QoS values. The algorithms can improve the correctness and automation performances of automated semantic web services composition. As an example, a concrete composite process is analyzed. Experimental results show the validity of the composite process.展开更多
In high-speed multiuser Time Reversal(TR)downlink systems,the transmission rate is degraded due to the presence of severe inter-user and inter-symbol interference.Moreover,maximizing the weighted sum rate in such syst...In high-speed multiuser Time Reversal(TR)downlink systems,the transmission rate is degraded due to the presence of severe inter-user and inter-symbol interference.Moreover,maximizing the weighted sum rate in such systems is a critical objective,since the weighting factors represent the priority of different users in different applications.However,it faces significant challenges as it is an NP-hard and non-convex problem.In order to suppress these interferences and maximize the weighted sum rate,in this paper we present a novel approach for the joint design of the pre-filters.The proposed method applies successive convex approximation to transform the original problem into a Second-Order Cone Programming(SOCP)problem.Then,a low-complexity iterative algorithm is provided to effectively solve the resulting SOCP problem.According to the simulation results,the proposed method reaches a local optimum within a few iterations and demonstrates superior performance in terms of weighted sum rate compared to the current algorithm.展开更多
In response to the complex working conditions of the power grid caused by the high proportion of new energy access,which leads to insufficient output accuracy of the second-order generalized integrator(SOGI)phaselocke...In response to the complex working conditions of the power grid caused by the high proportion of new energy access,which leads to insufficient output accuracy of the second-order generalized integrator(SOGI)phaselocked loop,this article proposes an improved frequency adaptive phase-locked loop structure for SOGI.Firstly,an amplitude compensation branch is introduced to compensate for the SOGI tracking fundamental frequency signal,ensuring the accuracy of the SOGI output orthogonal signal under frequency fluctuation conditions.Secondly,by cascading two adaptive SOGI modules,the suppression capability of low-order harmonics and Direct Current(DC)components has been improved.Finally,the positive and negative sequence separation method of orthogonal signals is introduced to eliminate the influence of unbalanced components on the phase-locked loop.The comparative experiment with the classic SOGI-PLL method shows that the proposed phase-locked loop structure effectively improves the accuracy of power grid synchronization detection under complex working conditions such as harmonic components,unbalanced components,and frequency fluctuations.It can complete frequency detection within 1.5 power frequency cycles,and the detected fundamental frequency positive sequence voltage has a higher sinuosity and harmonic distortion rate within 0.5%.展开更多
In this paper, a two step secure spectrum sensing algorithm is proposed for cognitive radio networks. In this algorithm, the sensing results of secondary users are pre-filtered and applying fuzzy logic, so, the overal...In this paper, a two step secure spectrum sensing algorithm is proposed for cognitive radio networks. In this algorithm, the sensing results of secondary users are pre-filtered and applying fuzzy logic, so, the overall sensing performance of the network is improved. To determine pre-filter parameters, statistical parameters of the sensing results are used to remove those sensing results which are far from the majority sensing results. However, to obtain a better performance in the spectrum sensing, we propose a fuzzy logic to nullify the effects of malicious users who transmit false sensing data to the fusion center. We further propose a Fuzzy Trust Level for each user as to weight the sensing result of the corresponding user before combining all sensing results in the fusion center. Simulation results demonstrate that our proposed algorithm yield significant improvement in the performance of the spectrum sensing and identifying malicious users.展开更多
This paper introduces an electrical drives control architecture combining a fractional-order controller and a setpoint pre-filter. The former is based on a fractional-order proportional-integral(PI) unit, with a non-i...This paper introduces an electrical drives control architecture combining a fractional-order controller and a setpoint pre-filter. The former is based on a fractional-order proportional-integral(PI) unit, with a non-integer order integral action, while the latter can be of integer or non-integer type. To satisfy robustness and dynamic performance specifications, the feedback controller is designed by a loop-shaping technique in the frequency domain. In particular, optimality of the feedback system is pursued to achieve input-output tracking. The setpoint pre-filter is designed by a dynamic inversion technique minimizing the difference between the ideal synthesized command signal(i.e., a smooth monotonic response) and the prefilter step response. Experimental tests validate the methodology and compare the performance of the proposed architecture with well-established control schemes that employ the classical PIbased symmetrical optimum method with a smoothing pre-filter.展开更多
The aim of this paper is to develop controllers for uncertain systems in the presence of stuck type actuator failures.A new scheme is proposed to design output feedback controllers for a class of uncertain systems hav...The aim of this paper is to develop controllers for uncertain systems in the presence of stuck type actuator failures.A new scheme is proposed to design output feedback controllers for a class of uncertain systems having redundant control inputs,with which the relative degrees of transfer functions are different.To deal with these inputs using backstepping technique,a pre-filter is introduced before each actuator such that its output is the input to the actuator.The orders of the pre-filters are chosen properly to ensure all their inputs can be designed at the same step in the systematic design.To compensate for the effects of possible failed actuators,more uncertain parameters than system parameters are required to be identified.With the proposed scheme,the global boundedness of the closed-loop system can still be ensured and the system output can be regulated to a specific value when some of the actuators＇ outputs are stuck at unknown fixed values.展开更多
The decentralized pre-filter based vector tracking loop(VTL)configuration with data wipe-off(DWO)method of the Global Positioning System(GPS)receiver is proposed for performance enhancement.It is a challenging task to...The decentralized pre-filter based vector tracking loop(VTL)configuration with data wipe-off(DWO)method of the Global Positioning System(GPS)receiver is proposed for performance enhancement.It is a challenging task to continuously track the satellites’signals in weak signal environment for the GPS receiver.VTL is a very attractive technique as it can provide tracking capability in signal-challenged environments.In the VTL,each channel will not form a loop independently.On the contrary,the signals in the channels of VTL are shared with each other;the navigation processor in turn predicts the code phases.Thus,the receiver can successfully track signals even the signal strength from individual satellite is weak.The tracking loop based on the pre-filter provides more flexible adjustment to specific environments to reduce noise interference.Therefore,even if the signals from some satellites are very weak the receiver can track them from the navigation results based on the other satellites.The navigation data,which contains information necessary to perform navigation computations,are binary phase-shift keying(BPSK)modulated onto the GPS carrier phase with the bit duration of 20 ms(i.e.,50 bits per second)for the GPS L1 C/A signals.The coherent integration interval can be extended for improved tracking performance in signal-challenged environment.However,tracking accuracy is decreased by possible data bit sign reversal.The DWO algorithm can be employed to remove the data bit in I and Q correlation values so as to avoid energy loss due to bit transitions when the integration interval of the correlator is extended over 20 ms under the low carrier-to-noise ratio(C/No)environments.The proposed method has an advantage to provide continuous tracking of signals and obtain improved navigation performance.Performance evaluation of the tracking capability as well as positioning accuracy will be presented.展开更多
The sterile insect technique(SIT)for controlling the Mediterranean fruit fly,Ceratitis capitata(Wiedemann),requires the mass-rearing of males in bio-facilities.This study summarizes the implementation of a Pre-Filter ...The sterile insect technique(SIT)for controlling the Mediterranean fruit fly,Ceratitis capitata(Wiedemann),requires the mass-rearing of males in bio-facilities.This study summarizes the implementation of a Pre-Filter system in the mass-rearing process of C.capitata at the Moscamed program's El Pino facility in Guatemala.The Pre-Filter selection process as presented here was aimed to increase the longevity of the VIENNA 8 D53-strain males released for pest control.Over a 9-year period(2015–2024),the longevity of these males was systemically monitored,and the impact of the Pre-Filter system on mortality,half-life,and survival rate were analyzed.Results indicated a significant reduction in mortality at 48 h,declining from 16.47%in 2017 to 2.56%in 2024.Concurrently,the half-life of males increased from 79.55 h in 2018 to 85.97 h in 2024.The Pre-Filter system shifted the frequency distribution of half-lives toward longer durations,with a peak observed between 76.14 and 86.14 h,whereas populations without the Pre-Filter exhibited shorter half-lives,peaking between 56.14 and 66.14 h.Comparative analyses with historical data(2005–2024)demonstrated that the Pre-Filter system significantly improved the male longevity,compared to pre-implementation periods during which mortality rates were higher and more variable.Additionally,the results revealed a gradual reduction in longevity variability within the population,indicating a more homogeneous longevity among the mass-reared males.展开更多
In order to ease the pass-band response distortion of the matrix pre-filter,a simple approach for designing matrix spatial filter is proposed,which minimizes the sum of the k maximal distortion norm（k is the number o...In order to ease the pass-band response distortion of the matrix pre-filter,a simple approach for designing matrix spatial filter is proposed,which minimizes the sum of the k maximal distortion norm（k is the number of the constraint points）within the pass-band,while constraining the filter response within the stop-band.Considering the costly amount of calculation of the high-resolution methods,an algorithm with small amount of calculation based on matrix pre-filtering and subspace fitting using acoustic vector array（MF-VSSF）is proposed.Through joint processing of signal subspace of both pressure and particle velocity,the pre-filtering matrix and the signal subspace is decreased to M-dimensional（M is the number of array-element）,hence reduces the time-consumption of the matrix pre-filter design and DOA searching.Simulation results show that,the method offers the same performance as MUSIC with pre-filtering,but has much lesser amount of calculation.Moreover,the designed prefilter can efficiently suppress the interference in the stop-band and improve the estimation and resolution performance of successive DOA estimators.展开更多
基金Supported by the National Natural Science Foundation of China （No. 61201252, 60775037） , Humanities and Social Sciences Foundation of the Ministry of Education （No. 10YJC870046 ）, Natural Science Research Key Project of Anhui Provincial Higher Education （No. KJ2011 A128） , Soft Science Project of Anhui Province （ No. 11020503009）.
文摘To support the rapid automatic services composition and fulfill multi-quality of service （multi- QoS） demand, we propose a novel approach to realize services composition automatically by a prefihering process. Aimed at a set of web services with similar functionality and different quality of service （QoS） , a semantic services chain is given and a corresponding constructing algorithm is proposed to construct the data structure. A pre-filtering process is put forward to find whether a composition service before planning exists. It can avoid aborted planning. An optimal planning algorithm is proposed which can choose the most suitable service from a lot of similar candidate services based on semantic service chains and multi-QoS values. The algorithms can improve the correctness and automation performances of automated semantic web services composition. As an example, a concrete composite process is analyzed. Experimental results show the validity of the composite process.
基金partially supported by the following funding sources:The National Natural Science Foundation of China(No.61771084)the Chongqing Graduate Scientific Research Innovation Project(No.CYB21200)。
文摘In high-speed multiuser Time Reversal(TR)downlink systems,the transmission rate is degraded due to the presence of severe inter-user and inter-symbol interference.Moreover,maximizing the weighted sum rate in such systems is a critical objective,since the weighting factors represent the priority of different users in different applications.However,it faces significant challenges as it is an NP-hard and non-convex problem.In order to suppress these interferences and maximize the weighted sum rate,in this paper we present a novel approach for the joint design of the pre-filters.The proposed method applies successive convex approximation to transform the original problem into a Second-Order Cone Programming(SOCP)problem.Then,a low-complexity iterative algorithm is provided to effectively solve the resulting SOCP problem.According to the simulation results,the proposed method reaches a local optimum within a few iterations and demonstrates superior performance in terms of weighted sum rate compared to the current algorithm.
基金supported by the Science and Technology Project of China Southern Power Grid Co.,Ltd.(Grant No.ZBKJXM20232471)the National Key R&D Program of China(Grant No.2021YFB1600200)the Innovation Capability Support Program of Shaanxi(Grant No.2022KXJ-144)。
文摘In response to the complex working conditions of the power grid caused by the high proportion of new energy access,which leads to insufficient output accuracy of the second-order generalized integrator(SOGI)phaselocked loop,this article proposes an improved frequency adaptive phase-locked loop structure for SOGI.Firstly,an amplitude compensation branch is introduced to compensate for the SOGI tracking fundamental frequency signal,ensuring the accuracy of the SOGI output orthogonal signal under frequency fluctuation conditions.Secondly,by cascading two adaptive SOGI modules,the suppression capability of low-order harmonics and Direct Current(DC)components has been improved.Finally,the positive and negative sequence separation method of orthogonal signals is introduced to eliminate the influence of unbalanced components on the phase-locked loop.The comparative experiment with the classic SOGI-PLL method shows that the proposed phase-locked loop structure effectively improves the accuracy of power grid synchronization detection under complex working conditions such as harmonic components,unbalanced components,and frequency fluctuations.It can complete frequency detection within 1.5 power frequency cycles,and the detected fundamental frequency positive sequence voltage has a higher sinuosity and harmonic distortion rate within 0.5%.
文摘In this paper, a two step secure spectrum sensing algorithm is proposed for cognitive radio networks. In this algorithm, the sensing results of secondary users are pre-filtered and applying fuzzy logic, so, the overall sensing performance of the network is improved. To determine pre-filter parameters, statistical parameters of the sensing results are used to remove those sensing results which are far from the majority sensing results. However, to obtain a better performance in the spectrum sensing, we propose a fuzzy logic to nullify the effects of malicious users who transmit false sensing data to the fusion center. We further propose a Fuzzy Trust Level for each user as to weight the sensing result of the corresponding user before combining all sensing results in the fusion center. Simulation results demonstrate that our proposed algorithm yield significant improvement in the performance of the spectrum sensing and identifying malicious users.
基金partially supported by the Australian Research Council(DP160104994)
文摘This paper introduces an electrical drives control architecture combining a fractional-order controller and a setpoint pre-filter. The former is based on a fractional-order proportional-integral(PI) unit, with a non-integer order integral action, while the latter can be of integer or non-integer type. To satisfy robustness and dynamic performance specifications, the feedback controller is designed by a loop-shaping technique in the frequency domain. In particular, optimality of the feedback system is pursued to achieve input-output tracking. The setpoint pre-filter is designed by a dynamic inversion technique minimizing the difference between the ideal synthesized command signal(i.e., a smooth monotonic response) and the prefilter step response. Experimental tests validate the methodology and compare the performance of the proposed architecture with well-established control schemes that employ the classical PIbased symmetrical optimum method with a smoothing pre-filter.
文摘The aim of this paper is to develop controllers for uncertain systems in the presence of stuck type actuator failures.A new scheme is proposed to design output feedback controllers for a class of uncertain systems having redundant control inputs,with which the relative degrees of transfer functions are different.To deal with these inputs using backstepping technique,a pre-filter is introduced before each actuator such that its output is the input to the actuator.The orders of the pre-filters are chosen properly to ensure all their inputs can be designed at the same step in the systematic design.To compensate for the effects of possible failed actuators,more uncertain parameters than system parameters are required to be identified.With the proposed scheme,the global boundedness of the closed-loop system can still be ensured and the system output can be regulated to a specific value when some of the actuators＇ outputs are stuck at unknown fixed values.
基金This work has been partially supported by the Ministry of Science and Technology,Taiwan[Grant Numbers MOST 101-2221-E-019-027-MY3 and MOST 109-2221-E-019-010].
文摘The decentralized pre-filter based vector tracking loop(VTL)configuration with data wipe-off(DWO)method of the Global Positioning System(GPS)receiver is proposed for performance enhancement.It is a challenging task to continuously track the satellites’signals in weak signal environment for the GPS receiver.VTL is a very attractive technique as it can provide tracking capability in signal-challenged environments.In the VTL,each channel will not form a loop independently.On the contrary,the signals in the channels of VTL are shared with each other;the navigation processor in turn predicts the code phases.Thus,the receiver can successfully track signals even the signal strength from individual satellite is weak.The tracking loop based on the pre-filter provides more flexible adjustment to specific environments to reduce noise interference.Therefore,even if the signals from some satellites are very weak the receiver can track them from the navigation results based on the other satellites.The navigation data,which contains information necessary to perform navigation computations,are binary phase-shift keying(BPSK)modulated onto the GPS carrier phase with the bit duration of 20 ms(i.e.,50 bits per second)for the GPS L1 C/A signals.The coherent integration interval can be extended for improved tracking performance in signal-challenged environment.However,tracking accuracy is decreased by possible data bit sign reversal.The DWO algorithm can be employed to remove the data bit in I and Q correlation values so as to avoid energy loss due to bit transitions when the integration interval of the correlator is extended over 20 ms under the low carrier-to-noise ratio(C/No)environments.The proposed method has an advantage to provide continuous tracking of signals and obtain improved navigation performance.Performance evaluation of the tracking capability as well as positioning accuracy will be presented.
文摘The sterile insect technique(SIT)for controlling the Mediterranean fruit fly,Ceratitis capitata(Wiedemann),requires the mass-rearing of males in bio-facilities.This study summarizes the implementation of a Pre-Filter system in the mass-rearing process of C.capitata at the Moscamed program's El Pino facility in Guatemala.The Pre-Filter selection process as presented here was aimed to increase the longevity of the VIENNA 8 D53-strain males released for pest control.Over a 9-year period(2015–2024),the longevity of these males was systemically monitored,and the impact of the Pre-Filter system on mortality,half-life,and survival rate were analyzed.Results indicated a significant reduction in mortality at 48 h,declining from 16.47%in 2017 to 2.56%in 2024.Concurrently,the half-life of males increased from 79.55 h in 2018 to 85.97 h in 2024.The Pre-Filter system shifted the frequency distribution of half-lives toward longer durations,with a peak observed between 76.14 and 86.14 h,whereas populations without the Pre-Filter exhibited shorter half-lives,peaking between 56.14 and 66.14 h.Comparative analyses with historical data(2005–2024)demonstrated that the Pre-Filter system significantly improved the male longevity,compared to pre-implementation periods during which mortality rates were higher and more variable.Additionally,the results revealed a gradual reduction in longevity variability within the population,indicating a more homogeneous longevity among the mass-reared males.
基金supported by the National Natural Science Foundation of China(61201411)
文摘In order to ease the pass-band response distortion of the matrix pre-filter,a simple approach for designing matrix spatial filter is proposed,which minimizes the sum of the k maximal distortion norm（k is the number of the constraint points）within the pass-band,while constraining the filter response within the stop-band.Considering the costly amount of calculation of the high-resolution methods,an algorithm with small amount of calculation based on matrix pre-filtering and subspace fitting using acoustic vector array（MF-VSSF）is proposed.Through joint processing of signal subspace of both pressure and particle velocity,the pre-filtering matrix and the signal subspace is decreased to M-dimensional（M is the number of array-element）,hence reduces the time-consumption of the matrix pre-filter design and DOA searching.Simulation results show that,the method offers the same performance as MUSIC with pre-filtering,but has much lesser amount of calculation.Moreover,the designed prefilter can efficiently suppress the interference in the stop-band and improve the estimation and resolution performance of successive DOA estimators.
