A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevaryin...A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.展开更多
Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate trackin...Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is solved.By utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is presented.The unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust term.Because the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system stability.Meanwhile,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering practicality.Finally,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator backlash.Contrast co-simulations and experiments illustrate the advantages of the proposed approach.展开更多
This paper describes new building construction methods that utilize soil thermal stabilization reghnes to compensate for negative environmental wanning and anthropogenic factors that impair fundament stability. Based ...This paper describes new building construction methods that utilize soil thermal stabilization reghnes to compensate for negative environmental wanning and anthropogenic factors that impair fundament stability. Based on long-standing research, the Funda- mentstroyarkos Company （FSA） of Tyumen, Russia has developed four primary seasonally active cooling devices （SCDs） that maintain soil in the frozen state, which are now extensively used on oil and gas facilities located in cold regions of Russia. This paper reports on the testing and validation of these SCDs in experimental conditions. On this basis, desigqls and technologies for building bases and foundations on permafrost with use of soil thermal stabilization systems, using carbon dioxide as the heat-transfer agent, were developed.展开更多
Dynesys,a pedicle-based dynamic stabilization system,was introduced to overcome some undesirable complications of fusion procedures.Nevertheless,the theoretical advantages of Dynesys over fusion have not been clearly ...Dynesys,a pedicle-based dynamic stabilization system,was introduced to overcome some undesirable complications of fusion procedures.Nevertheless,the theoretical advantages of Dynesys over fusion have not been clearly confirmed.The purpose of this editorial was to compare clinical and radiological outcomes of patients who underwent Dynesys system with those who underwent posterior lumbar fusion according to the existing literature and to see if the application of the Dynesys system is superior to the traditional lumbar fusion surgery.According to published clinical reports,the short-term effects of the Dynesys dynamic stabilization system are similar to that of traditional lumbar fusion surgery.Three comparative studies of Dynesys dynamic stabilization and fusion surgery with medium-term follow-up are encouraging.However,the results from four single-treatment-arm and small-sample studies of case series with long-term follow-up were not encouraging.In the present circumstances,it is not possible to conclude that the Dynesys dynamic stabilization system is superior to fusion surgery for lumbar degenerative diseases.展开更多
BACKGROUND In recent years,the mechanical concept of intervertebral disc regeneration has become more and more popular due to the increasing awareness of the importance of preservation of spine movement.Interestingly,...BACKGROUND In recent years,the mechanical concept of intervertebral disc regeneration has become more and more popular due to the increasing awareness of the importance of preservation of spine movement.Interestingly,there is increasing evidence,however,that dynamic stabilization systems may compensate nonphysiological loads,limit pathological movement,normalize disc height and intradiscal pressure,and provide an adaptive environment for disc regeneration.CASE SUMMARY The patient was a 54-year-old man,who presented with a 10-year history of mechanical back pain,which had become progressively serious and radiated into the left lower limb with numbness 3 mo prior.He had decreased muscle strength(class IV)of the left dorsal extensor and plantar flexor.Magnetic resonance imaging scans showed L3-S1 disc degeneration and L4-L5 disc herniation.Because the patient did not respond to various conservative treatments,he underwent a posterior L4-5 discectomy with fixation of the BioFlex dynamic stabilization system(Bio-Spine,Seoul,Korea).Preoperative symptoms were relieved and lumbar function was markedly improved after the operation.L4-L5 disc rehydration of instrumented segment was noted on magnetic resonance imaging at the 2-year follow-up.CONCLUSION Rehydration of the degenerated disc in our patient indicates that the BioFlex dynamic stabilization system may promote disc regeneration.Further research is needed to provide more evidence to support lumbar disc rehydration in the bridged segment using this system.展开更多
In order to stabilize the video module to build digital image stabilization image sequence, a method of using inertial measurement system is proposed. Through applying real-time attitude in- formation of the camera th...In order to stabilize the video module to build digital image stabilization image sequence, a method of using inertial measurement system is proposed. Through applying real-time attitude in- formation of the camera that obtained by high-precision attitude sensor to estimate the image motion vector and then to compensate for image, the purpose of stabilizing the image sequence can be a- chieved. Experiments demonstrate that this method has a high image stabilization precision, and the up to 16 frame/s video output rate completely meets the real-time requirements.展开更多
A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated ...A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch, the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filteration. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational, and zooming jitter and robust to local motions.展开更多
Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder r...Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm （MOGA） method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.展开更多
To improve the time and frequency reference standards used for radio astronomy and high precision atomic physics applications, we describe a novel stable frequency transmission technique. The approach uses a vertical-...To improve the time and frequency reference standards used for radio astronomy and high precision atomic physics applications, we describe a novel stable frequency transmission technique. The approach uses a vertical-cavity surface-emitting laser(VCSEL) based phase correction actuator. Using a frequency mixing process for feedback control, the phase noise induced along the 26 km G.655 optical fibre link was actively reduced. This was achieved by using a 1 310 nm dither controlled VCSEL phase error correction actuator together with the inherent chromatic dispersion properties of the fibre. The technique corrects phase noise and optical signal drift along the fibre at the transmission end. Fractional frequency instabilities across the G.655 fibre link of 4.44×10-12 at 1 s and 4.86×10-14 at 104 s are successfully reported.展开更多
Noise,vibration and harshness(NVH)problems in vehicle engineering are always challenging in both traditional vehicles and intelligent vehicles.Although high accuracy manufacturing,modern structural roads and advanced ...Noise,vibration and harshness(NVH)problems in vehicle engineering are always challenging in both traditional vehicles and intelligent vehicles.Although high accuracy manufacturing,modern structural roads and advanced suspension technology have already significantly reduced NVH problems and their impacts;off-road condition,obstacles and extreme operating condition could still trigger NVH problems unexpectedly.This paper proposes a vehicular electronic image stabilization(EIS)system to solve the vibration problem of the camera and ensure the environment perceptive function of vehicles.Firstly,feature point detection and matching based on an oriented FAST and rotated BRIEF(ORB)algorithm are implemented to match images in the process of EIS.Furthermore,a novel improved random sampling consensus algorithm(i-RANSAC)is proposed to eliminate mismatched feature points and increase the matching accuracy significantly.And an adaptive Kalman filter(AKF)is applied to improve the adaptability of the vehicular EIS.Finally,an experimental platform based on a gasoline model car was established to validate its performance.The experimental results show that the proposed EIS system can satisfy vehicular performance requirements even under off-road condition with obvious obstacles.展开更多
A novel image stabilization system is presented,which consists of a global feature point tracking based motion estimation,a Kalman filtering based motion smoothing and an image mosaic based panoramic compensation.The ...A novel image stabilization system is presented,which consists of a global feature point tracking based motion estimation,a Kalman filtering based motion smoothing and an image mosaic based panoramic compensation.The global motion is estimated using feature point matching and iteration with the least-square method.Then,the Kalman filter is applied to smooth the original motion vectors to effectively alleviate unwanted camera vibrations and follow the intentional camera scan.Lastly,the loss information of im...展开更多
A 2＂×2＂BC501A liquid scintillation detector with a gain stabilization system is developed and applied to neutron andγ-ray measurement on the EAST tokamak.Energy calibration of a liquid scintillator using a fas...A 2＂×2＂BC501A liquid scintillation detector with a gain stabilization system is developed and applied to neutron andγ-ray measurement on the EAST tokamak.Energy calibration of a liquid scintillator using a fast coincidence method is presented and compared with the Monte Carlo simulation.Determination of the proton light output function of the BC501A is presented.Results from dedicated experiments with an Am-Be neutron source,γsource and quasi-monoenergetic neutron beams,and from measurements on EAST tokamak are presented and discussed.展开更多
A real-time electronic image stabilization motion estimation method based on fast sub- block gray projection algorithm is proposed. In the method, each image is divided into a number of sub-blocks, and sub-blocks are ...A real-time electronic image stabilization motion estimation method based on fast sub- block gray projection algorithm is proposed. In the method, each image is divided into a number of sub-blocks, and sub-blocks are sifted with their gray gradients. After removing sub-blocks whose gray gradients are lower than the given threshold, the calculation amount of projection is reduced and the motion estimation accuracy is improved. Then gray projection is done in each remained sub- block, and global motion vector of the image is calculated according to the local motion vectors of sub-blocks and the affine motion model. The drawbacks as the local motions reducing the global mo- tion estimation accuracy and traditional gray projection algorithm could not deal with rotation are re- solved well by this algorithm. The experiment results show that the algorithm is more accurate and efficient than the gray projection algorithm.展开更多
Future applications of portable40Ca^(+)optical clocks require reliable magnetic field stabilization to improve frequency stability, which can be achieved by implementing an active and passive magnetic field noise supp...Future applications of portable40Ca^(+)optical clocks require reliable magnetic field stabilization to improve frequency stability, which can be achieved by implementing an active and passive magnetic field noise suppression system. On the one hand, we have optimized the magnetic shielding performance of the portable optical clock by reducing its apertures and optimizing its geometry;on the other hand, we have introduced an active magnetic field noise suppression system to further suppress the magnetic field noise experienced by the ions. These efforts reduced the ambient magnetic field noise by about 10000 times, significantly reduced the linewidth of the clock transition spectrum, improved the stability of the portable40Ca+optical clock, and created the conditions for using portable optical clocks in non-laboratory magnetic field environments. This active magnetic field suppression scheme has the advantages of simple installation and wide applicability.展开更多
Traditional type pumped storage system contributes to adjust the electric power unbalance between day and night, in general. The pump-turbine unit is prepared for the power stabilization system, in this serial researc...Traditional type pumped storage system contributes to adjust the electric power unbalance between day and night, in general. The pump-turbine unit is prepared for the power stabilization system, in this serial research, to provide the constant power with good quality for the grid system, even at the suddenly fluctuating/turbulent output from renewable energies. In the unit, the angular momentum changes through the front impeller/runner must be the same as that through the rear impeller/runner, that is, the axial flow at the outlet should be the same to the axial flow at the inlet. Such flow conditions are advantageous to work at not only the pumping mode but also the turbine mode. This work discusses experimentally the performance of the unit, and verifies that this type unit is very effective to both operating modes.展开更多
Dear Editor,This letter is concerned with stability analysis and stabilization design for sampled-data based load frequency control(LFC) systems via a data-driven method. By describing the dynamic behavior of LFC syst...Dear Editor,This letter is concerned with stability analysis and stabilization design for sampled-data based load frequency control(LFC) systems via a data-driven method. By describing the dynamic behavior of LFC systems based on a data-based representation, a stability criterion is derived to obtain the admissible maximum sampling interval(MSI) for a given controller and a design condition of the PI-type controller is further developed to meet the required MSI. Finally, the effectiveness of the proposed methods is verified by a case study.展开更多
This paper proposes a model-based control framework for vehicle platooning systems with secondorder nonlinear dynamics operating over switching signed networks,time-varying delays,and deception attacks.The study inclu...This paper proposes a model-based control framework for vehicle platooning systems with secondorder nonlinear dynamics operating over switching signed networks,time-varying delays,and deception attacks.The study includes two configurations:a leaderless structure using Finite-Time Non-Singular Terminal Bipartite Consensus(FNTBC)and Fixed-Time Bipartite Consensus(FXTBC),and a leader—follower structure ensuring structural balance and robustness against deceptive signals.In the leaderless model,a bipartite controller based on impulsive control theory,gauge transformation,and Markovian switching Lyapunov functions ensures mean-square stability and coordination under deception attacks and communication delays.The FNTBC achieves finite-time convergence depending on initial conditions,while the FXTBC guarantees fixed-time convergence independent of them,providing adaptability to different operating states.In the leader—follower case,a discontinuous impulsive control law synchronizes all followers with the leader despite deceptive attacks and switching topologies,maintaining robust coordination through nonlinear corrective mechanisms.To validate the approach,simulations are conducted on systems of five and seventeen vehicles in both leaderless and leader—follower configurations.The results demonstrate that the proposed framework achieves rapid consensus,strong robustness,and high resistance to deception attacks,offering a secure and scalable model-based control solution for modern vehicular communication networks.展开更多
Riboflavin,an important vitamin utilized in pharmaceutical products and as a feed additive,is mainly produced by metabolically engineered bacterial fermentation.However,the reliance on antibiotics in the production pr...Riboflavin,an important vitamin utilized in pharmaceutical products and as a feed additive,is mainly produced by metabolically engineered bacterial fermentation.However,the reliance on antibiotics in the production process leads to increased costs and safety risks.To address these challenges,an antibiotic-free Escherichia coli riboflavin producer was constructed using metabolic engineering approaches coupled with a novel plasmid stabilization system.Initially,competitive pathways and feedback inhibition were attenuated to enhance the metabolic flux towards riboflavin.Key genes in the purine pathway were overexpressed to boost the availability of riboflavin precursors.Subsequently,a plasmid stabilization system based on toxin was screened and characterized,achieving a plasmid retention rate of 84.9%after 10 days of passaging.Finally,transcriptomic analysis at the genome-wide level revealed several rate-limiting genes,including pgl,gnd,and yigB,which were subsequently upregulated,leading to a 26%improvement in riboflavin production.With optimization of the culture medium,the final strain allowed the production of 11.5 g/L of riboflavin with a yield of 90.4 mg/g glucose in 5 L bioreactors without antibiotics.These strategies can be extended to other plasmid-based riboflavin derivative production systems.展开更多
This paper deals with the singular chemotaxis-Navier-Stokes system with indirect signal consumption n_(t)+u·▽v=△n-Х▽·(n/v▽u);v_(t)+u·▽v=△v-uw;w_(t)+u·▽w=△w-w+n;u_(t)+(u·▽)u=△u-▽P+...This paper deals with the singular chemotaxis-Navier-Stokes system with indirect signal consumption n_(t)+u·▽v=△n-Х▽·(n/v▽u);v_(t)+u·▽v=△v-uw;w_(t)+u·▽w=△w-w+n;u_(t)+(u·▽)u=△u-▽P+n▽Ф;▽·u=0,x∈Ω,t>0 in a bounded and smooth domainΩ⊂ℝ2 with no-flux/no-flux/no-flux/no-slip boundary conditions,whereΦ∈W2,∞(Ω).A recent literature[Dai F,Liu B.J Differential Equations,2023,369:115–155]has proved that for all reasonably regular initial data,the associated initial-boundary value problem possesses a global classical solution,but qualitative information on the behavior of solution has never been touched so far.In stark contrast to the positive effect of indirect signal consumption mechanism on the global solvability of system,the analysis of asymptotic behavior of solution to the system with indirect signal consumption is essentially complicated than that with direct signal consumption because the favorable coupled structure between cells and signal is broken down by the indirect signal consumption mechanism.The present study shows that the global classical solution exponentially stabilizes toward the corresponding spatially homogeneous equilibria under a smallness condition on the initial cell mass.In comparison to the previously known result concerning the uniform convergence of solution to the system with direct signal consumption,our result inter alia provides a more in-depth understanding on the asymptotic behavior of solution.展开更多
This study investigates the stabilization challenge at the boundaries of a type II thermoelastic network with n-star configuration and terminal masses,which experiences non-uniform bounded external disturbances at its...This study investigates the stabilization challenge at the boundaries of a type II thermoelastic network with n-star configuration and terminal masses,which experiences non-uniform bounded external disturbances at its control boundary.This research employs an advanced active disturbance rejection control framework,incorporating an innovative observer with adaptive gain characteristics for precise disturbance estimation,coupled with a robust feedback control mechanism for disturbance compensation.The theoretical analysis establishes rigorous convergence proofs for the proposed time-dependent extended state observer.Furthermore,this investigation utilizes semigroup theory to validate the closed-loop system’s well-posed.Through comprehensive Lyapunov-based analysis,this study confirms the system’s capability to achieve exponential convergence of tracking errors while effectively mitigating disturbance effects.Extensive numerical experiments corroborate the theoretical findings,demonstrating the control scheme’s practical efficacy.展开更多
基金supported in part by the Nation Natural Science Foundation of China under Grant No.52175099China Postdoctoral Science Foundation under Grant No.2020M671494Jiangsu Planned Projects for Postdoctoral Research Funds under Grant No.2020Z179。
文摘A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.
基金the National Natural Science Foundation of China(No.52275062)and(No.52075262).
文摘Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is solved.By utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is presented.The unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust term.Because the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system stability.Meanwhile,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering practicality.Finally,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator backlash.Contrast co-simulations and experiments illustrate the advantages of the proposed approach.
文摘This paper describes new building construction methods that utilize soil thermal stabilization reghnes to compensate for negative environmental wanning and anthropogenic factors that impair fundament stability. Based on long-standing research, the Funda- mentstroyarkos Company （FSA） of Tyumen, Russia has developed four primary seasonally active cooling devices （SCDs） that maintain soil in the frozen state, which are now extensively used on oil and gas facilities located in cold regions of Russia. This paper reports on the testing and validation of these SCDs in experimental conditions. On this basis, desigqls and technologies for building bases and foundations on permafrost with use of soil thermal stabilization systems, using carbon dioxide as the heat-transfer agent, were developed.
文摘Dynesys,a pedicle-based dynamic stabilization system,was introduced to overcome some undesirable complications of fusion procedures.Nevertheless,the theoretical advantages of Dynesys over fusion have not been clearly confirmed.The purpose of this editorial was to compare clinical and radiological outcomes of patients who underwent Dynesys system with those who underwent posterior lumbar fusion according to the existing literature and to see if the application of the Dynesys system is superior to the traditional lumbar fusion surgery.According to published clinical reports,the short-term effects of the Dynesys dynamic stabilization system are similar to that of traditional lumbar fusion surgery.Three comparative studies of Dynesys dynamic stabilization and fusion surgery with medium-term follow-up are encouraging.However,the results from four single-treatment-arm and small-sample studies of case series with long-term follow-up were not encouraging.In the present circumstances,it is not possible to conclude that the Dynesys dynamic stabilization system is superior to fusion surgery for lumbar degenerative diseases.
基金Supported by Foundation of Capital Medical Development,Beijing,China,No.2010026.
文摘BACKGROUND In recent years,the mechanical concept of intervertebral disc regeneration has become more and more popular due to the increasing awareness of the importance of preservation of spine movement.Interestingly,there is increasing evidence,however,that dynamic stabilization systems may compensate nonphysiological loads,limit pathological movement,normalize disc height and intradiscal pressure,and provide an adaptive environment for disc regeneration.CASE SUMMARY The patient was a 54-year-old man,who presented with a 10-year history of mechanical back pain,which had become progressively serious and radiated into the left lower limb with numbness 3 mo prior.He had decreased muscle strength(class IV)of the left dorsal extensor and plantar flexor.Magnetic resonance imaging scans showed L3-S1 disc degeneration and L4-L5 disc herniation.Because the patient did not respond to various conservative treatments,he underwent a posterior L4-5 discectomy with fixation of the BioFlex dynamic stabilization system(Bio-Spine,Seoul,Korea).Preoperative symptoms were relieved and lumbar function was markedly improved after the operation.L4-L5 disc rehydration of instrumented segment was noted on magnetic resonance imaging at the 2-year follow-up.CONCLUSION Rehydration of the degenerated disc in our patient indicates that the BioFlex dynamic stabilization system may promote disc regeneration.Further research is needed to provide more evidence to support lumbar disc rehydration in the bridged segment using this system.
文摘In order to stabilize the video module to build digital image stabilization image sequence, a method of using inertial measurement system is proposed. Through applying real-time attitude in- formation of the camera that obtained by high-precision attitude sensor to estimate the image motion vector and then to compensate for image, the purpose of stabilizing the image sequence can be a- chieved. Experiments demonstrate that this method has a high image stabilization precision, and the up to 16 frame/s video output rate completely meets the real-time requirements.
基金the National Natural Science Foundation (60572152) of China and Science Foundation ofShaanxi Province (2005F26)
文摘A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch, the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filteration. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational, and zooming jitter and robust to local motions.
基金Foundation item： Supported by the National Natural Science Foundation of China （Grant No. 61174047） and the Fundamental Research Funds for the Central Universities （HEUCF041406）.
文摘Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm （MOGA） method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.
基金supported by the National Research Foundation of South Africa,Department of Science and Technology South Africa,Square Kilometre Array South Africa,Telkom,Cisco
文摘To improve the time and frequency reference standards used for radio astronomy and high precision atomic physics applications, we describe a novel stable frequency transmission technique. The approach uses a vertical-cavity surface-emitting laser(VCSEL) based phase correction actuator. Using a frequency mixing process for feedback control, the phase noise induced along the 26 km G.655 optical fibre link was actively reduced. This was achieved by using a 1 310 nm dither controlled VCSEL phase error correction actuator together with the inherent chromatic dispersion properties of the fibre. The technique corrects phase noise and optical signal drift along the fibre at the transmission end. Fractional frequency instabilities across the G.655 fibre link of 4.44×10-12 at 1 s and 4.86×10-14 at 104 s are successfully reported.
基金National Natural Science Foundation of China(Grant Nos.52072072,52025121 and 51605087).
文摘Noise,vibration and harshness(NVH)problems in vehicle engineering are always challenging in both traditional vehicles and intelligent vehicles.Although high accuracy manufacturing,modern structural roads and advanced suspension technology have already significantly reduced NVH problems and their impacts;off-road condition,obstacles and extreme operating condition could still trigger NVH problems unexpectedly.This paper proposes a vehicular electronic image stabilization(EIS)system to solve the vibration problem of the camera and ensure the environment perceptive function of vehicles.Firstly,feature point detection and matching based on an oriented FAST and rotated BRIEF(ORB)algorithm are implemented to match images in the process of EIS.Furthermore,a novel improved random sampling consensus algorithm(i-RANSAC)is proposed to eliminate mismatched feature points and increase the matching accuracy significantly.And an adaptive Kalman filter(AKF)is applied to improve the adaptability of the vehicular EIS.Finally,an experimental platform based on a gasoline model car was established to validate its performance.The experimental results show that the proposed EIS system can satisfy vehicular performance requirements even under off-road condition with obvious obstacles.
基金supported by the National "863 Program" on High Technology Research and Development of China (Grant No.2006AA01Z127)
文摘A novel image stabilization system is presented,which consists of a global feature point tracking based motion estimation,a Kalman filtering based motion smoothing and an image mosaic based panoramic compensation.The global motion is estimated using feature point matching and iteration with the least-square method.Then,the Kalman filter is applied to smooth the original motion vectors to effectively alleviate unwanted camera vibrations and follow the intentional camera scan.Lastly,the loss information of im...
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB106004 and 2012GB101003)National Natural Science Foundation of China(No.91226102)
文摘A 2＂×2＂BC501A liquid scintillation detector with a gain stabilization system is developed and applied to neutron andγ-ray measurement on the EAST tokamak.Energy calibration of a liquid scintillator using a fast coincidence method is presented and compared with the Monte Carlo simulation.Determination of the proton light output function of the BC501A is presented.Results from dedicated experiments with an Am-Be neutron source,γsource and quasi-monoenergetic neutron beams,and from measurements on EAST tokamak are presented and discussed.
基金Supported by the National Defense Scientific Research Project （ B2220132013 ）
文摘A real-time electronic image stabilization motion estimation method based on fast sub- block gray projection algorithm is proposed. In the method, each image is divided into a number of sub-blocks, and sub-blocks are sifted with their gray gradients. After removing sub-blocks whose gray gradients are lower than the given threshold, the calculation amount of projection is reduced and the motion estimation accuracy is improved. Then gray projection is done in each remained sub- block, and global motion vector of the image is calculated according to the local motion vectors of sub-blocks and the affine motion model. The drawbacks as the local motions reducing the global mo- tion estimation accuracy and traditional gray projection algorithm could not deal with rotation are re- solved well by this algorithm. The experiment results show that the algorithm is more accurate and efficient than the gray projection algorithm.
基金supported by the National Key R&D Program of China (Grant Nos.2022YFB3904001, 2022YFB3904004, and 2018YFA0307500)the National Natural Science Foundation of China (Grant Nos. 12022414 and 12121004)+3 种基金the CAS Youth Innovation Promotion Association (Grant Nos. Y201963 and Y2022099)the Natural Science Foundation of Hubei Province (Grant No. 2022CFA013)the CAS Project for Young Scientists in Basic Research (Grant No. YSBR-055)the Interdisciplinary Cultivation Project of the Innovation Academy for Precision Measurement of Science and Technology (Grant No. S21S2201)。
文摘Future applications of portable40Ca^(+)optical clocks require reliable magnetic field stabilization to improve frequency stability, which can be achieved by implementing an active and passive magnetic field noise suppression system. On the one hand, we have optimized the magnetic shielding performance of the portable optical clock by reducing its apertures and optimizing its geometry;on the other hand, we have introduced an active magnetic field noise suppression system to further suppress the magnetic field noise experienced by the ions. These efforts reduced the ambient magnetic field noise by about 10000 times, significantly reduced the linewidth of the clock transition spectrum, improved the stability of the portable40Ca+optical clock, and created the conditions for using portable optical clocks in non-laboratory magnetic field environments. This active magnetic field suppression scheme has the advantages of simple installation and wide applicability.
文摘Traditional type pumped storage system contributes to adjust the electric power unbalance between day and night, in general. The pump-turbine unit is prepared for the power stabilization system, in this serial research, to provide the constant power with good quality for the grid system, even at the suddenly fluctuating/turbulent output from renewable energies. In the unit, the angular momentum changes through the front impeller/runner must be the same as that through the rear impeller/runner, that is, the axial flow at the outlet should be the same to the axial flow at the inlet. Such flow conditions are advantageous to work at not only the pumping mode but also the turbine mode. This work discusses experimentally the performance of the unit, and verifies that this type unit is very effective to both operating modes.
基金supported in part by the National Natural Science Foundation of China(62373337,62373333)the 111 Project(B17040)State Key Laboratory of Advanced Electromagnetic Technology(2024KF002)
文摘Dear Editor,This letter is concerned with stability analysis and stabilization design for sampled-data based load frequency control(LFC) systems via a data-driven method. By describing the dynamic behavior of LFC systems based on a data-based representation, a stability criterion is derived to obtain the admissible maximum sampling interval(MSI) for a given controller and a design condition of the PI-type controller is further developed to meet the required MSI. Finally, the effectiveness of the proposed methods is verified by a case study.
基金Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under grant number RGP.2/103/46”Deanship of Scientific Research at Northern Border University,Arar,Saudi Arabia for funding this research work through project number“NBU-FFR-2025-871-15”funding from Prince Sattam bin Abdulaziz University project number(PSAU/2025/R/1447).
文摘This paper proposes a model-based control framework for vehicle platooning systems with secondorder nonlinear dynamics operating over switching signed networks,time-varying delays,and deception attacks.The study includes two configurations:a leaderless structure using Finite-Time Non-Singular Terminal Bipartite Consensus(FNTBC)and Fixed-Time Bipartite Consensus(FXTBC),and a leader—follower structure ensuring structural balance and robustness against deceptive signals.In the leaderless model,a bipartite controller based on impulsive control theory,gauge transformation,and Markovian switching Lyapunov functions ensures mean-square stability and coordination under deception attacks and communication delays.The FNTBC achieves finite-time convergence depending on initial conditions,while the FXTBC guarantees fixed-time convergence independent of them,providing adaptability to different operating states.In the leader—follower case,a discontinuous impulsive control law synchronizes all followers with the leader despite deceptive attacks and switching topologies,maintaining robust coordination through nonlinear corrective mechanisms.To validate the approach,simulations are conducted on systems of five and seventeen vehicles in both leaderless and leader—follower configurations.The results demonstrate that the proposed framework achieves rapid consensus,strong robustness,and high resistance to deception attacks,offering a secure and scalable model-based control solution for modern vehicular communication networks.
基金supported by the National Key Research and Devel-opment Program of China(No.2021YFC2100900,2022YFA0912200)the National Natural Science Foundation of China(No.32071470,32300063)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20221080,No.BK20210464)the Research Program of State Key Laboratory of Food Science and Resources,Jiangnan University(No.SKLF-ZZB-202408).
文摘Riboflavin,an important vitamin utilized in pharmaceutical products and as a feed additive,is mainly produced by metabolically engineered bacterial fermentation.However,the reliance on antibiotics in the production process leads to increased costs and safety risks.To address these challenges,an antibiotic-free Escherichia coli riboflavin producer was constructed using metabolic engineering approaches coupled with a novel plasmid stabilization system.Initially,competitive pathways and feedback inhibition were attenuated to enhance the metabolic flux towards riboflavin.Key genes in the purine pathway were overexpressed to boost the availability of riboflavin precursors.Subsequently,a plasmid stabilization system based on toxin was screened and characterized,achieving a plasmid retention rate of 84.9%after 10 days of passaging.Finally,transcriptomic analysis at the genome-wide level revealed several rate-limiting genes,including pgl,gnd,and yigB,which were subsequently upregulated,leading to a 26%improvement in riboflavin production.With optimization of the culture medium,the final strain allowed the production of 11.5 g/L of riboflavin with a yield of 90.4 mg/g glucose in 5 L bioreactors without antibiotics.These strategies can be extended to other plasmid-based riboflavin derivative production systems.
文摘This paper deals with the singular chemotaxis-Navier-Stokes system with indirect signal consumption n_(t)+u·▽v=△n-Х▽·(n/v▽u);v_(t)+u·▽v=△v-uw;w_(t)+u·▽w=△w-w+n;u_(t)+(u·▽)u=△u-▽P+n▽Ф;▽·u=0,x∈Ω,t>0 in a bounded and smooth domainΩ⊂ℝ2 with no-flux/no-flux/no-flux/no-slip boundary conditions,whereΦ∈W2,∞(Ω).A recent literature[Dai F,Liu B.J Differential Equations,2023,369:115–155]has proved that for all reasonably regular initial data,the associated initial-boundary value problem possesses a global classical solution,but qualitative information on the behavior of solution has never been touched so far.In stark contrast to the positive effect of indirect signal consumption mechanism on the global solvability of system,the analysis of asymptotic behavior of solution to the system with indirect signal consumption is essentially complicated than that with direct signal consumption because the favorable coupled structure between cells and signal is broken down by the indirect signal consumption mechanism.The present study shows that the global classical solution exponentially stabilizes toward the corresponding spatially homogeneous equilibria under a smallness condition on the initial cell mass.In comparison to the previously known result concerning the uniform convergence of solution to the system with direct signal consumption,our result inter alia provides a more in-depth understanding on the asymptotic behavior of solution.
文摘This study investigates the stabilization challenge at the boundaries of a type II thermoelastic network with n-star configuration and terminal masses,which experiences non-uniform bounded external disturbances at its control boundary.This research employs an advanced active disturbance rejection control framework,incorporating an innovative observer with adaptive gain characteristics for precise disturbance estimation,coupled with a robust feedback control mechanism for disturbance compensation.The theoretical analysis establishes rigorous convergence proofs for the proposed time-dependent extended state observer.Furthermore,this investigation utilizes semigroup theory to validate the closed-loop system’s well-posed.Through comprehensive Lyapunov-based analysis,this study confirms the system’s capability to achieve exponential convergence of tracking errors while effectively mitigating disturbance effects.Extensive numerical experiments corroborate the theoretical findings,demonstrating the control scheme’s practical efficacy.
