The behavior of multiple modes before and during minor disruption with the external resonant magnetic perturbations(RMPs)has been studied on a J-TEXT tokamak.The main component of RMPs is m/n=2/1,where m and n are the...The behavior of multiple modes before and during minor disruption with the external resonant magnetic perturbations(RMPs)has been studied on a J-TEXT tokamak.The main component of RMPs is m/n=2/1,where m and n are the numbers of the poloidal and toroidal modes,respectively.During the mode-locking caused by RMPs,it is found that before a minor or a major disruption(if there is no minor disruption),strong oscillations in both electron temperature and density occur if the edge safety factor q_(a)>3.The analysis shows that the oscillations are caused by the m/n=3/1 mode.In addition,using the ECE,Mirnov coils and 2D electron cyclotron emission imaging diagnostic systems,it is found that a thermal collapse occurs on the inner side of the 2/1magnetic island during the minor disruption,and before the collapse,a 3/2 island increases,after the collapse,the 3/2 island may disappear.Moreover,the study also shows that these 3/1,2/1 and 3/2modes play roles in the thermal collapse of disruptions.展开更多
The main problems of the traditional software talent training are that the knowledge learned is out of touch of the industry,weak ability to solve complex engineering problems and the comprehensive quality cannot meet...The main problems of the traditional software talent training are that the knowledge learned is out of touch of the industry,weak ability to solve complex engineering problems and the comprehensive quality cannot meet the requirements of enterprises.Taking the course of digital image processing as an example,this paper analyzes the key steps in the training process in details,and proposes a multiple mode collaborative based software engineering talent training mechanism,which brings the key subjects of teaching materials,teachers,students,enterprises,subjects into a unified training mechanism,so as to provide a new ideas for software talent teaching.展开更多
A terminal sliding mode fuzzy control based on multiple sliding surfaces was proposed for ship course tracking steering, which takes account of rudder characteristics and parameter uncertainty. In order to solve the p...A terminal sliding mode fuzzy control based on multiple sliding surfaces was proposed for ship course tracking steering, which takes account of rudder characteristics and parameter uncertainty. In order to solve the problem, the controller was designed by employing the universal approximation property of fuzzy logic system, the advantage of Nussbaum function, and using multiple sliding mode control algorithm based on the recursive technique. In the last step of designing, a nonsingular terminal sliding mode was utilized to drive the last state of the system to converge in a finite period of time, and high-order sliding mode control law was designed to eliminate the chattering and make the system robust. The simulation results showed that the controller designed here could track a desired course fast and accurately. It also exhibited strong robustness peculiarly to system, and had better adaptive ability than traditional PID control algorithms.展开更多
BACKGROUND Patients with colorectal cancer may need postoperative nursing to improve prognosis,and conventional nursing is not effective.Clinical research is needed to explore nursing methods that can more effectively...BACKGROUND Patients with colorectal cancer may need postoperative nursing to improve prognosis,and conventional nursing is not effective.Clinical research is needed to explore nursing methods that can more effectively improve postoperative conditions on colorectal cancer patients undergoing colostomy.AIM To explore the effect of internet multiple linkage mode-based extended care combined with in-hospital comfort care on colorectal cancer patients undergoing colostomy.METHODS Data from 187 patients with colostomy treated in our hospital from May 2019 to March 2022 were collected and divided into three groups,A(n=62),B(n=62)and C(n=63),according to different intervention methods.Group A received internet multiple linkage mode-based extended care combined with in-hospital comfort care.Group B received internet multiple linkage mode-based extended care.Group C received usual care intervention.Complications were compared among the three groups.The stoma self-efficacy scale,Hamilton Anxiety Scale,RESULTS The complication rate of group A,B and C(16.13%,20.97%and 60.32%,respectively)was significantly different(all P<0.05).The incidence of complications in groups A and B was lower than that in group C,and there was no significant difference between groups A and B(P>0.05).After intervention,the scores of ostomy care,social contact,diet choice,confidence in maintaining vitality,confidence in self-care of ostomy,confidence in sexual life,confidence in sexual satisfaction and confidence in physical labor in the three groups were all higher than before intervention,and the scores of groups A and B were higher than those of group C,with statistical significance(P<0.05).The Hamilton Anxiety Scale and Hamilton Depression Scale scores of the three groups after intervention were lower than those before intervention.The scores of groups A and B were lower than those of group C,and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).There was a statist-ically significant difference in cancer-induced fatigue among the three groups(P<0.05).After intervention,the scores of physical health,psychological health,social health and mental health of the three groups were lower than before the intervention.The scores of group A and B were lower than that of group C;and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).CONCLUSION Internet multiple linkage mode-based extended care combined with in-hospital comfort care can effectively improve self-efficacy,bad mood,cancer-related fatigue and life quality of colorectal cancer patients undergoing colostomy.展开更多
Impact dampers are usually used to suppress single mode resonance. The goal of this paper is to clarify the difference when the impact damper suppresses the resonances of different modes. A cantilever beam equipped wi...Impact dampers are usually used to suppress single mode resonance. The goal of this paper is to clarify the difference when the impact damper suppresses the resonances of different modes. A cantilever beam equipped with the impact damper is modeled. The elastic contact of the ball and the cantilever beam is described by using the Hertz contact model. The viscous damper between the ball and the cantilever beam is modeled to consume the vibrational energy of the cantilever beam. A piecewise ordinary differential-partial differential equation of the cantilever beam is established, including equations with and without the impact damper. The vibration responses of the cantilever beam with and without the impact damper are numerically calculated. The effects of the impact absorber parameters on the vibration reduction are examined. The results show that multiple resonance peaks of the cantilever beam can be effectively suppressed by the impact damper. Specifically, all resonance amplitudes can be reduced by a larger weight ball. Moreover, the impacting gap is very effective in suppressing the vibration of the cantilever beam. More importantly, there is an optimal impacting gap for each resonance mode of the cantilever beam, but the optimal gap for each mode is different.展开更多
Using periodic permanent magnet(PPM)electromagnetic acoustic transducers(EMATs),different shear horizontal(SH)guided wave modes can form simultaneously in some situations,which can interfere with the inspection.The ma...Using periodic permanent magnet(PPM)electromagnetic acoustic transducers(EMATs),different shear horizontal(SH)guided wave modes can form simultaneously in some situations,which can interfere with the inspection.The main cause of this phenomenon(typically named multiple modes)is related to the frequency bandwidth of excitation signals and the transducer spatial bandwidth.Simply narrowing the frequency bandwidth cannot effectively limit the number of different SH modes.Previous researches showed that unnecessary SH wave modes can be eliminated by using dual EMATs.However,in practical applications,it is more convenient to change the excitation frequency than to use dual EMATs.In this paper,the stress boundary conditions of the PPM-EMAT are analyzed,the analytical expression of SH guided wave is established,and the magnitude of SH guided wave mode under continuous tone and tone-burst input is obtained.A method to generate a single SH mode by re-selecting an operating point is proposed.Furthermore,the influence of the frequency bandwidth of the tone-burst signal is analyzed.Finally,a single SH mode excitation is achieved with tone-burst input.展开更多
There are multiple operating modes in the real industrial process, and the collected data follow the complex multimodal distribution, so most traditional process monitoring methods are no longer applicable because the...There are multiple operating modes in the real industrial process, and the collected data follow the complex multimodal distribution, so most traditional process monitoring methods are no longer applicable because their presumptions are that sampled-data should obey the single Gaussian distribution or non-Gaussian distribution. In order to solve these problems, a novel weighted local standardization(WLS) strategy is proposed to standardize the multimodal data, which can eliminate the multi-mode characteristics of the collected data, and normalize them into unimodal data distribution. After detailed analysis of the raised data preprocessing strategy, a new algorithm using WLS strategy with support vector data description(SVDD) is put forward to apply for multi-mode monitoring process. Unlike the strategy of building multiple local models, the developed method only contains a model without the prior knowledge of multi-mode process. To demonstrate the proposed method's validity, it is applied to a numerical example and a Tennessee Eastman(TE) process. Finally, the simulation results show that the WLS strategy is very effective to standardize multimodal data, and the WLS-SVDD monitoring method has great advantages over the traditional SVDD and PCA combined with a local standardization strategy(LNS-PCA) in multi-mode process monitoring.展开更多
In considering the characteristic of a rudder,the maneuvers of a ship were described by an unmatched uncertain nonlinear mathematic model with unknown virtual control coefficient and parameter uncertainties.In order t...In considering the characteristic of a rudder,the maneuvers of a ship were described by an unmatched uncertain nonlinear mathematic model with unknown virtual control coefficient and parameter uncertainties.In order to solve the uncertainties in the ship heading control,specifically the controller singular and paramount re-estimation problem,a new multiple sliding-mode adaptive fuzzy control algorithm was proposed by combining Nussbaum gain technology,the approximation property of fuzzy logic systems,and a multiple sliding-mode control algorithm.Based on the Lyapunov function,it was proven in theory that the controller made all signals in the nonlinear system of unmatched uncertain ship motion uniformly bounded,with tracking errors converging to zero.Simulation results show that the demonstrated controller design can track a desired course fast and accurately.It also exhibits strong robustness peculiarity in relation to system uncertainties and disturbances.展开更多
Multiple failure modes tend to be identified in the reliability analysis of a redundant truss structure.This identification process involves updating the model for identifying the next potential failure members.Herein...Multiple failure modes tend to be identified in the reliability analysis of a redundant truss structure.This identification process involves updating the model for identifying the next potential failure members.Herein we intend to update the finite element model automatically in the identification process of failure modes and further perform the system reliability analysis efficiently.This study presents a framework that is implemented through the joint simulation of MATLAB and APDL and consists of three parts:reliability index of a single member,identification of dominant failure modes,and system-level reliability analysis for system reliability analysis of truss structures.Firstly,RSM(response surface method)combines with a constrained optimization model to calculate the reliability indices ofmembers.Then theβ-unzipping method is adopted to identify the dominant failuremodes,and the system function in MATLAB,as well as the EKILL command in APDL,is used to facilitate the automatic update of the finite element model and realize load-redistribution.Besides,the differential equivalence recursion algorithmis performed to approximate the reliability indices of failuremodes efficiently and accurately.Eventually,the PNET(probabilistic network evaluation technique)is used to calculate the joint failure probability as well as the system reliability index.Two illustrative examples demonstrate the accuracy and efficiency of the proposed system reliability analysis framework through comparison with corresponding references.展开更多
Comprehensive parks offer a wide range of functions and serve diverse populations.Assessing their accessibility based on multiple travel modes and real-time travel data is of great importance for promoting the rationa...Comprehensive parks offer a wide range of functions and serve diverse populations.Assessing their accessibility based on multiple travel modes and real-time travel data is of great importance for promoting the rational distribution and efficient service of these parks.By using real-time travel data obtained through the API(Application Programming Interface)of Gaode Maps and applying the Ga2SFCA(Gaussian Two-Step Floating Catchment Area)method,this study explores the accessibility of comprehensive parks in the central urban area of Suzhou city under multiple travel modes.The findings are as follows.①Walking accessibility shows significant improvement under the 15-minute threshold compared to the 10-minutethreshold scenario;cycling accessibility increases synchronically with the time threshold,maintaining relatively stable travel costs;driving is the preferred mode for long-duration and long-distance trips;whereas the accessibility of bus travel exhibits substantial spatial variation.②The overall accessibility within the studied time thresholds shows that driving is better than cycling,followed by bus travel and walking.Especially for trips within a 4 km range between communities and comprehensive parks,cycling accessibility surpasses that of buses.③The high-value distribution of accessibility to comprehensive parks,as measured under walking,cycling,and driving modes,is relatively balanced,while the overall accessibility coverage of bus travel is relatively low.This study reveals the differences and characteristics of comprehensive park accessibility under multiple travel modes,providing insights for reassessing the existing service radius indicator and offering a theoretical basis for optimizing the allocation of parks based on population distribution.展开更多
Competition of multiple Gortler modes in hypersonic boundary layer flows are investigated with the local and marching methods. The wall-layer mode （mode W） and the trapped-layer mode （mode T） both occur in the com...Competition of multiple Gortler modes in hypersonic boundary layer flows are investigated with the local and marching methods. The wall-layer mode （mode W） and the trapped-layer mode （mode T） both occur in the compressible boundary layer where there exists a temperature adjustment layer near the upper edge. The mode T has the largest growth rate at a lower Gortler number while the mode W dominates at larger G/Srtler numbers. These two modes are both responsible for the flow transition in the hypersonic flows especially when Gortler number is in the high value range in which the crossover of these two modes takes place. Such high Gortler numbers are virtually far beyond the neutral regime. The nonparallel base flows, therefore, cease to influence the stability behavior of the Gortler modes. The effects of the Mach number on the multiple Gortler modes are studied within a chosen Mach number of 0.95, 2, 4 and 6. When the flow Mach number is sufficiently large, e.g., Ma ≥4, the growth rate crossover of the mode T and mode W occurs both in the conventional G-β map as well as on the route downstream for a fixed wavelength disturbance. Four particular regions （Region T, T-W, W-T and W） around the crossover point are highlighted with the marching analysis and the result matches that of the local analysis. The initial disturbance of a normal mode maintains the shape in its corresponding dominating region while a shape-transformation occurs outside this region.展开更多
This paper proposes a modified centralized shifted Rayleigh filter（MCSRF） algorithm for tracking boost phase of ballistic missile（BM） trajectory with a highly nonlinear dynamical model based on bearings-only.This ...This paper proposes a modified centralized shifted Rayleigh filter（MCSRF） algorithm for tracking boost phase of ballistic missile（BM） trajectory with a highly nonlinear dynamical model based on bearings-only.This paper contributes three folds.Firstly,the mathematical model of an MCSRF for multiple passive sensors is derived.Then,minimum entropy based onedimensional optimization search to adaptively adjust the probability of the different filters for real time state estimation is deployed.Finally,the unscented transform（UT） is introduced to resolve the asymmetric state estimation problem.Simulation results show that the proposed algorithm can consecutively track the BM precisely during the boost phase.In comparison with the unscented Kalman filter（UKF） algorithm,the proposed algorithm effectively reduces the tracking position and velocity root mean square（RMS） errors,which will make more sense for early precision interception.展开更多
Power converters are the typical switched systems which operate based on the alternate switching of the semiconductor switches.The operating mode of power converters consists of several operating stages in one switchi...Power converters are the typical switched systems which operate based on the alternate switching of the semiconductor switches.The operating mode of power converters consists of several operating stages in one switching period.Each operating stage refers to a sub-circuit or equivalent circuit where different sub-circuits are switched in a fixed order according to the control strategy design.Power converter may operate in different operating modes even with the same control scheme,for example,the DC-DC converter has differing performance under the continuous conduction mode(CCM)and discontinuous conduction mode(DCM).Thus,it is necessary to have a comprehensive understanding of the converter’s characteristics in advance to avoid undesired operation in practice.In this paper,the power converter is considered as a graph made up of several meshes.All sub-circuits in power converter can then be obtained by the mesh combination algorithm,and the operating mode can be constructed by considering the preset switching ON/OFF scheme.Ultimately,the typical waveforms in different modes can be predicted,which is useful to identify abnormal phenomena.Cúk converter is taken as an example to demonstrate the proposed multiple mode analysis method.It is found that there are four kinds of phenomena in addition to the well-known CCM and DCM.Finally,the experimental results are provided and show good agreement with the theoretical analysis.展开更多
Combining the advantages of the stratified sampling and the importance sampling, a stratified importance sampling method （SISM） is presented to analyze the reliability sensitivity for structure with multiple failure...Combining the advantages of the stratified sampling and the importance sampling, a stratified importance sampling method （SISM） is presented to analyze the reliability sensitivity for structure with multiple failure modes. In the presented method, the variable space is divided into several disjoint subspace by n-dimensional coordinate planes at the mean point of the random vec- tor, and the importance sampling functions in the subspaces are constructed by keeping the sampling center at the mean point and augmenting the standard deviation by a factor of 2. The sample size generated from the importance sampling function in each subspace is determined by the contribution of the subspace to the reliability sensitivity, which can be estimated by iterative simulation in the sampling process. The formulae of the reliability sensitivity estimation, the variance and the coefficient of variation are derived for the presented SISM. Comparing with the Monte Carlo method, the stratified sampling method and the importance sampling method, the presented SISM has wider applicability and higher calculation efficiency, which is demonstrated by numerical examples. Finally, the reliability sensitivity analysis of flap structure is illustrated that the SISM can be applied to engineering structure.展开更多
The flexibility of MIP technology to meet market demand is mainly introduced in this study. Their commercial application and technical principle are analyzed too. The MIP technology with wide feed adaptability can for...The flexibility of MIP technology to meet market demand is mainly introduced in this study. Their commercial application and technical principle are analyzed too. The MIP technology with wide feed adaptability can form a good combination with other technologies. The MIP technology has been applied extensively in China. Based on this platform, the CGP, MIP-LTG and MIP-DCR technologies have been developed, which can further improve the flexibility of MIP technology. Based on its novel reaction control technique with a sole sequential two-zone riser, the MIP users can easily switch to different operating modes between producing either more clean gasoline and propylene or diesel through changing the catalysts and varying the operating conditions. That offers MIP users with enough production flexibility and a rational production arrangement to meet the market demand. The MIP-DCR technology with less dry gas and coke yields can provide a more flexible operating mode since the catalysts to oil ratio has become an independent variable.展开更多
Multiple failure modes of gas compressor stations have not been modeled into risk evaluation of electricity-gas integrated energy system(EGIES).This paper presents a method to incorporate multiple failure modes of com...Multiple failure modes of gas compressor stations have not been modeled into risk evaluation of electricity-gas integrated energy system(EGIES).This paper presents a method to incorporate multiple failure modes of compressor stations with bypass systems in the EGIES risk evaluation.Three outage models representing multi-states and multi-failure-modes of com-pressor stations and a bi-level Monte Carlo sampling algorithm for the models are developed.A novel network model of EGIES considering compressor stations with multiple failure modes is presented.An EGIES with a modified RBTS and an 11-node gas system is used to demonstrate the effectiveness of the proposed method and models.Results indicate that compressor stations have both positive and negative significant impacts on the risk of EGIES.Bypass systems for compressor stations can effectively offset the negative impacts.Ignoring compressor stations and their station failures in the risk evaluation of EGIES may result in an inaccurate estimation of the system risk levels and even lead to a misleading conclusion in system planning.Index Terms-Compressor station,electricity-gas integrated energy system,multiple failure modes,risk evaluation.展开更多
Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots(FWIDSMRs)due to the flexible allocation of multiple maneuver modes.To address t...Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots(FWIDSMRs)due to the flexible allocation of multiple maneuver modes.To address this problem,this study proposes a novel multiple mode-based navigation system,which can achieve efficient motion planning and accurate tracking control.To reduce the calculation burden and obtain a comprehensive optimized global path,a kinodynamic interior-exterior cell exploration planning method,which leverages the hybrid space of available modes with an incorporated exploration guiding algorithm,is designed.By utilizing the sampled subgoals and the constructed global path,local planning is then performed to avoid unexpected obstacles and potential collisions.With the desired profile curvature and preselected mode,a fuzzy adaptive receding horizon control is proposed such that the online updating of the predictive horizon is realized to enhance the trajectory-following precision.The tracking controller design is achieved using the quadratic programming(QP)technique,and the primal-dual neural network optimization technique is used to solve the QP problem.Experimental results on a real-time FWIDSMR validate that the proposed method shows superior features over some existing methods in terms of efficiency and accuracy.展开更多
Wave propagation is studied in structures consisting of alternate left- and right-handed layers. Bragg gap and zero-n gap appear in different frequency regions of the structure. The periodicity of the structure is bro...Wave propagation is studied in structures consisting of alternate left- and right-handed layers. Bragg gap and zero-n gap appear in different frequency regions of the structure. The periodicity of the structure is broken by simply reversing the order of the layers in one half of the structure, resulting in defect modes located inside the zero-n gap and Bragg gap. These modes can be made very narrow by adding more layers in the structure. The defect mode located inside the zero-n gap is sensitive to the symmetry of the structure and insensitive to the angle of incidence of the incoming radiation. Multiple modes are also generated inside the gaps by repeating the structural pattern. Thus, a simple structure can be used for single and multiple modes that are imDortant for different applications.展开更多
Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced relia...Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced reliability-based robust geotechnical design method,which can consider multiple failures and uncertainty of statistical information.A universal design sample was conducted to verify the necessity of considering the uncertainty of statistical information.Ultimate limit state and serviceability limit state of braced excavations were defined,and point estimating method was used to evaluate the standard deviation of failure probabilities.Two-objective and three-objective optimization models were developed to illustrate the application of proposed methods in detail.In addition,the performance of optimization algorithms and further application of multiple-objective models were discussed.The results from this study indicate that the proposed method has a good performance in determining the optimal design with reasonable robustness and cost.New algorithms have higher efficiency in solving nonlinear and multiple-objective optimization problems than the 2nd Non-dominated sorting genetic algo-rithm.This study can guide the design of retaining systems of braced excavations in clay.展开更多
基金National MCF Energy R&D Program of China(No.2018YFE0310300)National Natural Science Foundation of China(Nos.51821005,51977221 and 61903384)+1 种基金Fundamental Research Funds for the Central Universities(No.CZY20028)Startup Funds for the Introduction of Talents,South-Central Minzu University(No.YZZ19026)。
文摘The behavior of multiple modes before and during minor disruption with the external resonant magnetic perturbations(RMPs)has been studied on a J-TEXT tokamak.The main component of RMPs is m/n=2/1,where m and n are the numbers of the poloidal and toroidal modes,respectively.During the mode-locking caused by RMPs,it is found that before a minor or a major disruption(if there is no minor disruption),strong oscillations in both electron temperature and density occur if the edge safety factor q_(a)>3.The analysis shows that the oscillations are caused by the m/n=3/1 mode.In addition,using the ECE,Mirnov coils and 2D electron cyclotron emission imaging diagnostic systems,it is found that a thermal collapse occurs on the inner side of the 2/1magnetic island during the minor disruption,and before the collapse,a 3/2 island increases,after the collapse,the 3/2 island may disappear.Moreover,the study also shows that these 3/1,2/1 and 3/2modes play roles in the thermal collapse of disruptions.
文摘The main problems of the traditional software talent training are that the knowledge learned is out of touch of the industry,weak ability to solve complex engineering problems and the comprehensive quality cannot meet the requirements of enterprises.Taking the course of digital image processing as an example,this paper analyzes the key steps in the training process in details,and proposes a multiple mode collaborative based software engineering talent training mechanism,which brings the key subjects of teaching materials,teachers,students,enterprises,subjects into a unified training mechanism,so as to provide a new ideas for software talent teaching.
基金the National Natural Science Foundation ofChina (60974136)
文摘A terminal sliding mode fuzzy control based on multiple sliding surfaces was proposed for ship course tracking steering, which takes account of rudder characteristics and parameter uncertainty. In order to solve the problem, the controller was designed by employing the universal approximation property of fuzzy logic system, the advantage of Nussbaum function, and using multiple sliding mode control algorithm based on the recursive technique. In the last step of designing, a nonsingular terminal sliding mode was utilized to drive the last state of the system to converge in a finite period of time, and high-order sliding mode control law was designed to eliminate the chattering and make the system robust. The simulation results showed that the controller designed here could track a desired course fast and accurately. It also exhibited strong robustness peculiarly to system, and had better adaptive ability than traditional PID control algorithms.
基金Supported by Clinical Teaching Base of Jiangsu Medical Vocational College,No.20219141.
文摘BACKGROUND Patients with colorectal cancer may need postoperative nursing to improve prognosis,and conventional nursing is not effective.Clinical research is needed to explore nursing methods that can more effectively improve postoperative conditions on colorectal cancer patients undergoing colostomy.AIM To explore the effect of internet multiple linkage mode-based extended care combined with in-hospital comfort care on colorectal cancer patients undergoing colostomy.METHODS Data from 187 patients with colostomy treated in our hospital from May 2019 to March 2022 were collected and divided into three groups,A(n=62),B(n=62)and C(n=63),according to different intervention methods.Group A received internet multiple linkage mode-based extended care combined with in-hospital comfort care.Group B received internet multiple linkage mode-based extended care.Group C received usual care intervention.Complications were compared among the three groups.The stoma self-efficacy scale,Hamilton Anxiety Scale,RESULTS The complication rate of group A,B and C(16.13%,20.97%and 60.32%,respectively)was significantly different(all P<0.05).The incidence of complications in groups A and B was lower than that in group C,and there was no significant difference between groups A and B(P>0.05).After intervention,the scores of ostomy care,social contact,diet choice,confidence in maintaining vitality,confidence in self-care of ostomy,confidence in sexual life,confidence in sexual satisfaction and confidence in physical labor in the three groups were all higher than before intervention,and the scores of groups A and B were higher than those of group C,with statistical significance(P<0.05).The Hamilton Anxiety Scale and Hamilton Depression Scale scores of the three groups after intervention were lower than those before intervention.The scores of groups A and B were lower than those of group C,and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).There was a statist-ically significant difference in cancer-induced fatigue among the three groups(P<0.05).After intervention,the scores of physical health,psychological health,social health and mental health of the three groups were lower than before the intervention.The scores of group A and B were lower than that of group C;and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).CONCLUSION Internet multiple linkage mode-based extended care combined with in-hospital comfort care can effectively improve self-efficacy,bad mood,cancer-related fatigue and life quality of colorectal cancer patients undergoing colostomy.
基金the National Natural Science Foundation of China(No.11772181)the Program of Shanghai Municipal Education Commission(No.2019-01-07-00-09-E0018)the Key Research Projects of Shanghai Science and Technology Commission(No.18010500100)。
文摘Impact dampers are usually used to suppress single mode resonance. The goal of this paper is to clarify the difference when the impact damper suppresses the resonances of different modes. A cantilever beam equipped with the impact damper is modeled. The elastic contact of the ball and the cantilever beam is described by using the Hertz contact model. The viscous damper between the ball and the cantilever beam is modeled to consume the vibrational energy of the cantilever beam. A piecewise ordinary differential-partial differential equation of the cantilever beam is established, including equations with and without the impact damper. The vibration responses of the cantilever beam with and without the impact damper are numerically calculated. The effects of the impact absorber parameters on the vibration reduction are examined. The results show that multiple resonance peaks of the cantilever beam can be effectively suppressed by the impact damper. Specifically, all resonance amplitudes can be reduced by a larger weight ball. Moreover, the impacting gap is very effective in suppressing the vibration of the cantilever beam. More importantly, there is an optimal impacting gap for each resonance mode of the cantilever beam, but the optimal gap for each mode is different.
基金Project supported by the National Natural Science Foundation of China(Grant No.51977044).
文摘Using periodic permanent magnet(PPM)electromagnetic acoustic transducers(EMATs),different shear horizontal(SH)guided wave modes can form simultaneously in some situations,which can interfere with the inspection.The main cause of this phenomenon(typically named multiple modes)is related to the frequency bandwidth of excitation signals and the transducer spatial bandwidth.Simply narrowing the frequency bandwidth cannot effectively limit the number of different SH modes.Previous researches showed that unnecessary SH wave modes can be eliminated by using dual EMATs.However,in practical applications,it is more convenient to change the excitation frequency than to use dual EMATs.In this paper,the stress boundary conditions of the PPM-EMAT are analyzed,the analytical expression of SH guided wave is established,and the magnitude of SH guided wave mode under continuous tone and tone-burst input is obtained.A method to generate a single SH mode by re-selecting an operating point is proposed.Furthermore,the influence of the frequency bandwidth of the tone-burst signal is analyzed.Finally,a single SH mode excitation is achieved with tone-burst input.
基金Project(61374140)supported by the National Natural Science Foundation of China
文摘There are multiple operating modes in the real industrial process, and the collected data follow the complex multimodal distribution, so most traditional process monitoring methods are no longer applicable because their presumptions are that sampled-data should obey the single Gaussian distribution or non-Gaussian distribution. In order to solve these problems, a novel weighted local standardization(WLS) strategy is proposed to standardize the multimodal data, which can eliminate the multi-mode characteristics of the collected data, and normalize them into unimodal data distribution. After detailed analysis of the raised data preprocessing strategy, a new algorithm using WLS strategy with support vector data description(SVDD) is put forward to apply for multi-mode monitoring process. Unlike the strategy of building multiple local models, the developed method only contains a model without the prior knowledge of multi-mode process. To demonstrate the proposed method's validity, it is applied to a numerical example and a Tennessee Eastman(TE) process. Finally, the simulation results show that the WLS strategy is very effective to standardize multimodal data, and the WLS-SVDD monitoring method has great advantages over the traditional SVDD and PCA combined with a local standardization strategy(LNS-PCA) in multi-mode process monitoring.
基金Supported by the National Natural Science Foundation of China under Grant No.60974136
文摘In considering the characteristic of a rudder,the maneuvers of a ship were described by an unmatched uncertain nonlinear mathematic model with unknown virtual control coefficient and parameter uncertainties.In order to solve the uncertainties in the ship heading control,specifically the controller singular and paramount re-estimation problem,a new multiple sliding-mode adaptive fuzzy control algorithm was proposed by combining Nussbaum gain technology,the approximation property of fuzzy logic systems,and a multiple sliding-mode control algorithm.Based on the Lyapunov function,it was proven in theory that the controller made all signals in the nonlinear system of unmatched uncertain ship motion uniformly bounded,with tracking errors converging to zero.Simulation results show that the demonstrated controller design can track a desired course fast and accurately.It also exhibits strong robustness peculiarity in relation to system uncertainties and disturbances.
基金support from the National Key R&D Program of China(Grant Nos.2021YFB2600605,2021YFB2600600)the Overseas Scholar Program in the Hebei Province(C20190514)+1 种基金from the State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Project(ZZ2020-20)from the Youth Foundation of Hebei Science and Technology Research Project(QN2018108).
文摘Multiple failure modes tend to be identified in the reliability analysis of a redundant truss structure.This identification process involves updating the model for identifying the next potential failure members.Herein we intend to update the finite element model automatically in the identification process of failure modes and further perform the system reliability analysis efficiently.This study presents a framework that is implemented through the joint simulation of MATLAB and APDL and consists of three parts:reliability index of a single member,identification of dominant failure modes,and system-level reliability analysis for system reliability analysis of truss structures.Firstly,RSM(response surface method)combines with a constrained optimization model to calculate the reliability indices ofmembers.Then theβ-unzipping method is adopted to identify the dominant failuremodes,and the system function in MATLAB,as well as the EKILL command in APDL,is used to facilitate the automatic update of the finite element model and realize load-redistribution.Besides,the differential equivalence recursion algorithmis performed to approximate the reliability indices of failuremodes efficiently and accurately.Eventually,the PNET(probabilistic network evaluation technique)is used to calculate the joint failure probability as well as the system reliability index.Two illustrative examples demonstrate the accuracy and efficiency of the proposed system reliability analysis framework through comparison with corresponding references.
基金funded by the National Natural Science“Research on the Pattern,Evolution,and Mechanism of Spatial Differentiation of Green Space Ratio in Urban Built-up Areas of China Based on Spatial Econometric Analysis”(No.51778389)National Natural Science Foundation“Response Mechanisms of Urban Green Space to Public Health Crises and Resilience Optimization Research”(No.42471218)+3 种基金Qinglan Project in Jiangsu Colleges and UniversitiesJiangsu Provincial Enterprise Graduate Workstation(Suzhou Institute of Landscape Architecture Design Co.,Ltd.)Second Phase of Jiangsu University Brand Major Construction Project(Landscape Architecture)Key Discipline of Jiangsu Province During the 14th FiveYear Plan Period(Landscape Architecture)。
文摘Comprehensive parks offer a wide range of functions and serve diverse populations.Assessing their accessibility based on multiple travel modes and real-time travel data is of great importance for promoting the rational distribution and efficient service of these parks.By using real-time travel data obtained through the API(Application Programming Interface)of Gaode Maps and applying the Ga2SFCA(Gaussian Two-Step Floating Catchment Area)method,this study explores the accessibility of comprehensive parks in the central urban area of Suzhou city under multiple travel modes.The findings are as follows.①Walking accessibility shows significant improvement under the 15-minute threshold compared to the 10-minutethreshold scenario;cycling accessibility increases synchronically with the time threshold,maintaining relatively stable travel costs;driving is the preferred mode for long-duration and long-distance trips;whereas the accessibility of bus travel exhibits substantial spatial variation.②The overall accessibility within the studied time thresholds shows that driving is better than cycling,followed by bus travel and walking.Especially for trips within a 4 km range between communities and comprehensive parks,cycling accessibility surpasses that of buses.③The high-value distribution of accessibility to comprehensive parks,as measured under walking,cycling,and driving modes,is relatively balanced,while the overall accessibility coverage of bus travel is relatively low.This study reveals the differences and characteristics of comprehensive park accessibility under multiple travel modes,providing insights for reassessing the existing service radius indicator and offering a theoretical basis for optimizing the allocation of parks based on population distribution.
基金supported by the National Natural Science Foundation of China(Grant Nos.10932005 and 11202115)
文摘Competition of multiple Gortler modes in hypersonic boundary layer flows are investigated with the local and marching methods. The wall-layer mode （mode W） and the trapped-layer mode （mode T） both occur in the compressible boundary layer where there exists a temperature adjustment layer near the upper edge. The mode T has the largest growth rate at a lower Gortler number while the mode W dominates at larger G/Srtler numbers. These two modes are both responsible for the flow transition in the hypersonic flows especially when Gortler number is in the high value range in which the crossover of these two modes takes place. Such high Gortler numbers are virtually far beyond the neutral regime. The nonparallel base flows, therefore, cease to influence the stability behavior of the Gortler modes. The effects of the Mach number on the multiple Gortler modes are studied within a chosen Mach number of 0.95, 2, 4 and 6. When the flow Mach number is sufficiently large, e.g., Ma ≥4, the growth rate crossover of the mode T and mode W occurs both in the conventional G-β map as well as on the route downstream for a fixed wavelength disturbance. Four particular regions （Region T, T-W, W-T and W） around the crossover point are highlighted with the marching analysis and the result matches that of the local analysis. The initial disturbance of a normal mode maintains the shape in its corresponding dominating region while a shape-transformation occurs outside this region.
基金supported by the Aerospace Science and Technology Innovation Foundation (CASC0202-3)
文摘This paper proposes a modified centralized shifted Rayleigh filter（MCSRF） algorithm for tracking boost phase of ballistic missile（BM） trajectory with a highly nonlinear dynamical model based on bearings-only.This paper contributes three folds.Firstly,the mathematical model of an MCSRF for multiple passive sensors is derived.Then,minimum entropy based onedimensional optimization search to adaptively adjust the probability of the different filters for real time state estimation is deployed.Finally,the unscented transform（UT） is introduced to resolve the asymmetric state estimation problem.Simulation results show that the proposed algorithm can consecutively track the BM precisely during the boost phase.In comparison with the unscented Kalman filter（UKF） algorithm,the proposed algorithm effectively reduces the tracking position and velocity root mean square（RMS） errors,which will make more sense for early precision interception.
基金Supported by the key program of national natural science foundation of China under Grant 51437005.
文摘Power converters are the typical switched systems which operate based on the alternate switching of the semiconductor switches.The operating mode of power converters consists of several operating stages in one switching period.Each operating stage refers to a sub-circuit or equivalent circuit where different sub-circuits are switched in a fixed order according to the control strategy design.Power converter may operate in different operating modes even with the same control scheme,for example,the DC-DC converter has differing performance under the continuous conduction mode(CCM)and discontinuous conduction mode(DCM).Thus,it is necessary to have a comprehensive understanding of the converter’s characteristics in advance to avoid undesired operation in practice.In this paper,the power converter is considered as a graph made up of several meshes.All sub-circuits in power converter can then be obtained by the mesh combination algorithm,and the operating mode can be constructed by considering the preset switching ON/OFF scheme.Ultimately,the typical waveforms in different modes can be predicted,which is useful to identify abnormal phenomena.Cúk converter is taken as an example to demonstrate the proposed multiple mode analysis method.It is found that there are four kinds of phenomena in addition to the well-known CCM and DCM.Finally,the experimental results are provided and show good agreement with the theoretical analysis.
基金National Natural Science Foundation of China (10572117,10802063,50875213)Aeronautical Science Foundation of China (2007ZA53012)+1 种基金New Century Program For Excellent Talents of Ministry of Education of China (NCET-05-0868)National High-tech Research and Development Program (2007AA04Z401)
文摘Combining the advantages of the stratified sampling and the importance sampling, a stratified importance sampling method （SISM） is presented to analyze the reliability sensitivity for structure with multiple failure modes. In the presented method, the variable space is divided into several disjoint subspace by n-dimensional coordinate planes at the mean point of the random vec- tor, and the importance sampling functions in the subspaces are constructed by keeping the sampling center at the mean point and augmenting the standard deviation by a factor of 2. The sample size generated from the importance sampling function in each subspace is determined by the contribution of the subspace to the reliability sensitivity, which can be estimated by iterative simulation in the sampling process. The formulae of the reliability sensitivity estimation, the variance and the coefficient of variation are derived for the presented SISM. Comparing with the Monte Carlo method, the stratified sampling method and the importance sampling method, the presented SISM has wider applicability and higher calculation efficiency, which is demonstrated by numerical examples. Finally, the reliability sensitivity analysis of flap structure is illustrated that the SISM can be applied to engineering structure.
文摘The flexibility of MIP technology to meet market demand is mainly introduced in this study. Their commercial application and technical principle are analyzed too. The MIP technology with wide feed adaptability can form a good combination with other technologies. The MIP technology has been applied extensively in China. Based on this platform, the CGP, MIP-LTG and MIP-DCR technologies have been developed, which can further improve the flexibility of MIP technology. Based on its novel reaction control technique with a sole sequential two-zone riser, the MIP users can easily switch to different operating modes between producing either more clean gasoline and propylene or diesel through changing the catalysts and varying the operating conditions. That offers MIP users with enough production flexibility and a rational production arrangement to meet the market demand. The MIP-DCR technology with less dry gas and coke yields can provide a more flexible operating mode since the catalysts to oil ratio has become an independent variable.
基金supported in part by the National Science Fund for Distinguished Young Scholars(51725701)and the National“111”Project of China(B08036)。
文摘Multiple failure modes of gas compressor stations have not been modeled into risk evaluation of electricity-gas integrated energy system(EGIES).This paper presents a method to incorporate multiple failure modes of compressor stations with bypass systems in the EGIES risk evaluation.Three outage models representing multi-states and multi-failure-modes of com-pressor stations and a bi-level Monte Carlo sampling algorithm for the models are developed.A novel network model of EGIES considering compressor stations with multiple failure modes is presented.An EGIES with a modified RBTS and an 11-node gas system is used to demonstrate the effectiveness of the proposed method and models.Results indicate that compressor stations have both positive and negative significant impacts on the risk of EGIES.Bypass systems for compressor stations can effectively offset the negative impacts.Ignoring compressor stations and their station failures in the risk evaluation of EGIES may result in an inaccurate estimation of the system risk levels and even lead to a misleading conclusion in system planning.Index Terms-Compressor station,electricity-gas integrated energy system,multiple failure modes,risk evaluation.
基金The work was funded in part by the Guangdong Major Science and Technology Project,China(Grant Nos.2019B090919003 and 2017B090913001)in part by the China Postdoctoral Science Foundation(Grant No.2019M650179)+2 种基金in part by the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2019ZT08Z780)in part by the Dongguan Innovative Research Team Program,China(Grant No.201536000100031)in part by the Guangdong HUST Industrial Technology Research Institute,Guangdong Provincial Key Laboratory of Manufacturing Equipment Digitization,China(Grant No.2020B1212060014).
文摘Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots(FWIDSMRs)due to the flexible allocation of multiple maneuver modes.To address this problem,this study proposes a novel multiple mode-based navigation system,which can achieve efficient motion planning and accurate tracking control.To reduce the calculation burden and obtain a comprehensive optimized global path,a kinodynamic interior-exterior cell exploration planning method,which leverages the hybrid space of available modes with an incorporated exploration guiding algorithm,is designed.By utilizing the sampled subgoals and the constructed global path,local planning is then performed to avoid unexpected obstacles and potential collisions.With the desired profile curvature and preselected mode,a fuzzy adaptive receding horizon control is proposed such that the online updating of the predictive horizon is realized to enhance the trajectory-following precision.The tracking controller design is achieved using the quadratic programming(QP)technique,and the primal-dual neural network optimization technique is used to solve the QP problem.Experimental results on a real-time FWIDSMR validate that the proposed method shows superior features over some existing methods in terms of efficiency and accuracy.
文摘Wave propagation is studied in structures consisting of alternate left- and right-handed layers. Bragg gap and zero-n gap appear in different frequency regions of the structure. The periodicity of the structure is broken by simply reversing the order of the layers in one half of the structure, resulting in defect modes located inside the zero-n gap and Bragg gap. These modes can be made very narrow by adding more layers in the structure. The defect mode located inside the zero-n gap is sensitive to the symmetry of the structure and insensitive to the angle of incidence of the incoming radiation. Multiple modes are also generated inside the gaps by repeating the structural pattern. Thus, a simple structure can be used for single and multiple modes that are imDortant for different applications.
基金supported by the National Natural Science Foundation of China(Grant No.52078086)Program of Distinguished Young Scholars,Natural Science Foundation of Chongqing,China(Grant No.cstc2020jcyj-jq0087).
文摘Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced reliability-based robust geotechnical design method,which can consider multiple failures and uncertainty of statistical information.A universal design sample was conducted to verify the necessity of considering the uncertainty of statistical information.Ultimate limit state and serviceability limit state of braced excavations were defined,and point estimating method was used to evaluate the standard deviation of failure probabilities.Two-objective and three-objective optimization models were developed to illustrate the application of proposed methods in detail.In addition,the performance of optimization algorithms and further application of multiple-objective models were discussed.The results from this study indicate that the proposed method has a good performance in determining the optimal design with reasonable robustness and cost.New algorithms have higher efficiency in solving nonlinear and multiple-objective optimization problems than the 2nd Non-dominated sorting genetic algo-rithm.This study can guide the design of retaining systems of braced excavations in clay.
