This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mi...This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mission is disturbed by the measurement noise and the target adversarial behavior.To address these problems,a model-free Combined Adaptive-length Datadriven Predictive Controller(CADPC)is proposed.It consists of a separated subsystem identification method and a combined predictive control strategy.The subsystem identification method is composed of an adaptive data length,thereby reducing sensitivity to undetermined measurement noises and disturbances.Based on the subsystem identification,the combined predictive controller is established,reducing calculating resource.The stability of the CADPC is rigorously proven using the Input-to-State Stable(ISS)theorem and the small-gain theorem.Simulations demonstrate that CADPC effectively handles the model-free space robot post operation in the presence of significant disturbances,state measurement noise,and control input errors.It achieves improved steady-state accuracy,reduced steady-state control consumption,and minimized control input chattering.展开更多
This study investigates the correlation between musical competence and English prosodic production as well as the associations among their internal components.Eighty Chinese EFL learners in college took the musical pe...This study investigates the correlation between musical competence and English prosodic production as well as the associations among their internal components.Eighty Chinese EFL learners in college took the musical perception test,musical production test and English prosodic production test in sequence.In order to take a closer look at the prosodic performance,taking native English speakers as a reference,we also conducted an in-depth acoustic analysis of the English prosody produced by six cases in both high and low musical competence groups with the aid of Praat and ToBI.Our results indicate that students with high musical competence tend to outperform those with low musical competence in English prosodic production.However,musical perception competence seems to have a greater correlation with English prosodic competence than musical production competence.In addition,beat alignment or tempo(related to time and stress)could be the most associated component in musical competence with English prosody,while melody in music was double confirmed to be unhelpful.It was also spotted that cases with high musical competence performed more native-like patterns of phrase accent,boundary tones,intonational phrases as well as placement of stress.The results have important theoretical implications for the construct interpretation of musical competence,and also suggest that rhythmic perception training could be the most effective way to transfer music achievement to English speech prosody.展开更多
This article provides a comprehensive analysis of the current feedback practices in Chinese college English as a foreign language(EFL)learners’writing classes,with a particular focus on understanding why students pre...This article provides a comprehensive analysis of the current feedback practices in Chinese college English as a foreign language(EFL)learners’writing classes,with a particular focus on understanding why students predominantly prefer teacher feedback to peer feedback.It identifies three major reasons shedding light on the underlying factors that make teacher feedback more appealing compared to other types of feedback.Considering the growing influence of online teaching,this study also proposes four practical solutions to enhance the effectiveness of feedback in the context of Chinese EFL learners’writing.The suggested solutions aim to address the challenges posed by online teaching while optimizing feedback mechanisms to support learners’writing development.Additionally,the author examines the potential of adopting a pluralistic feedback approach,which integrates teacher feedback,peer feedback,and online automated evaluation system to improve the overall feedback experience in the blended teaching environment.By combining these various feedback modes,the study explores their feasibility and effectiveness in enhancing the learning outcomes of Chinese EFL learners.The pluralistic feedback model is presented as a viable alternative that can address the limitations of relying solely on one-way teacher feedback,thus promoting a more dynamic and interactive learning process for college EFL learners in China.展开更多
Online interactive learning plays a crucial role in improving online education quality.This grounded theory study examines:(1)what key factors shape EFL learners’online interactive learning,(2)how these factors form ...Online interactive learning plays a crucial role in improving online education quality.This grounded theory study examines:(1)what key factors shape EFL learners’online interactive learning,(2)how these factors form an empirically validated model,and(3)how they interact within this model,through systematic analysis of 9,207 discussion forum posts from a Chinese University MOOC platform.Results demonstrate that learning drive,course structure,teaching competence,interaction behavior,expected outcomes,and online learning context significantly influence EFL online interactive learning.The analysis reveals two key mechanisms:expected outcomes mediate the effects of learning drive(β=0.45),course structure,teaching competence,and interaction behavior(β=0.35)on learning outcomes,while online learning context moderates these relationships(β=0.25).Specifically,learning drive provides intrinsic/extrinsic motivation,whereas course structure,teaching competence,interaction behavior,and expected outcomes collectively enhance interaction quality and sustainability.These findings,derived through rigorous grounded theory methodology involving open,axial,and selective coding of large-scale interaction data,yield three key contributions:(1)a comprehensive theoretical model of EFL online learning dynamics,(2)empirical validation of mediation/moderation mechanisms,and(3)practical strategies for designing scaffolded interaction protocols and adaptive feedback systems.The study establishes that its theoretically saturated model(achieved after analyzing 7,366 posts with 1,841 verification cases)offers educators evidence-based approaches to optimize collaborative interaction in digital EFL environments.展开更多
Language education has predominantly focused on classroom instruction and pedagogical strategies,yet the sociological aspects of learning-especially the family’s role-are often overlooked in English as a Foreign Lang...Language education has predominantly focused on classroom instruction and pedagogical strategies,yet the sociological aspects of learning-especially the family’s role-are often overlooked in English as a Foreign Language(EFL)contexts.This study explores how parental attitudes,support systems,and disciplinary approaches influence Turkish university students’oral fluency in English.While educators and curricula are frequently held accountable for low communicative competence,this paper posits that sociocultural factors originating from the home environment play a crucial role.Utilizing a qualitative-dominant mixed-methods design with 210 undergraduate EFL learners and 24 lecturers from four Turkish universities,data were gathered through questionnaires,interviews,and parental focus groups.Findings indicate that students with supportive and engaged parents exhibit greater self-efficacy,confidence,and linguistic agency in communication tasks.In contrast,those from indifferent or authoritarian families experience anxiety,low motivation,and stagnation in oral skills.Grounded in Bourdieu’s social capital theory,Bronfenbrenner’s ecological systems theory,and Coleman’s social context of learning,this study conceptualizes the family as an“invisible classroom”where linguistic habits,discipline,and cultural aspirations are cultivated.The paper concludes by proposing a Family-Engaged EFL Fluency Model(FE-EFM)that integrates learner development within a framework of sociological co-responsibility involving parents,educators,and institutions.展开更多
This study integrates multiple sources of data(transaction data,policy text,public opinion data)with visualization techniques(such as heat maps,time-series trend charts,3D building brochures)to construct an analysis f...This study integrates multiple sources of data(transaction data,policy text,public opinion data)with visualization techniques(such as heat maps,time-series trend charts,3D building brochures)to construct an analysis framework for the Chengdu real estate market.By using the Adaptive Neuro-Fuzzy Inference System(ANFIS)prediction model,spatial GIS(Geographic Information System analysis)analysis,and interactive dashboards,this study reveals market differentiation,policy impacts,and changes in demand structure,thereby providing decision support for the government,enterprises,and homebuyers.展开更多
To address the issue of instability or even imbalance in the orientation and attitude control of quadrotor unmanned aerial vehicles(QUAVs)under random disturbances,this paper proposes a distributed antidisturbance dat...To address the issue of instability or even imbalance in the orientation and attitude control of quadrotor unmanned aerial vehicles(QUAVs)under random disturbances,this paper proposes a distributed antidisturbance data-driven event-triggered fusion control method,which achieves efficient fault diagnosis while suppressing random disturbances and mitigating communication conflicts within the QUAV swarm.First,the impact of random disturbances on the UAV swarm is analyzed,and a model for orientation and attitude control of QUAVs under stochastic perturbations is established,with the disturbance gain threshold determined.Second,a fault diagnosis system based on a high-gain observer is designed,constructing a fault gain criterion by integrating orientation and attitude information from QUAVs.Subsequently,a model-free dynamic linearization-based data modeling(MFDLDM)framework is developed using model-free adaptive control,which efficiently fits the nonlinear control model of the QUAV swarm while reducing temporal constraints on control data.On this basis,this paper constructs a distributed data-driven event-triggered controller based on the staggered communication mechanism,which consists of an equivalent QUAV controller and an event-triggered controller,and is able to reduce the communication conflicts while suppressing the influence of random interference.Finally,by incorporating random disturbances into the controller,comparative experiments and physical validations are conducted on the QUAV platforms,fully demonstrating the strong adaptability and robustness of the proposed distributed event-triggered fault-tolerant control system.展开更多
Wetting deformation in earth-rockfill dams is a critical factor influencingdam safety.Although numerous mathematical models have been developed to describe this phenomenon,most of them rely on empirical formulations a...Wetting deformation in earth-rockfill dams is a critical factor influencingdam safety.Although numerous mathematical models have been developed to describe this phenomenon,most of them rely on empirical formulations and lack prior knowledge of model parameters,which is essential for Bayesian parameter inversion to enhance accuracy and reduce uncertainty.This study introduces a datadriven approach to establishing prior knowledge of earth-rockfill dams.Driving factors are utilized to determine the potential range of model parameters,and settlement changes within this range are calculated.The results are iteratively compared with actual monitoring data until the calculated range encompasses the observed data,thereby providing prior knowledge of the model parameters.The proposed method is applied to the right-bank earth-rockfilldam of Danjiangkou.Employing a Gibbs sample size of 30,000,the proposed method effectively calibrates the prior knowledge of the wetting model parameters,achieving a root mean square error(RMSE)of 5.18 mm for the settlement predictions.By comparison,the use of non-informative priors with sample sizes of 30,000 and 50,000 results in significantly larger RMSE values of 11.97 mm and 16.07 mm,respectively.Furthermore,the computational efficiencyof the proposed method is demonstrated by an inversion computation time of 902 s for 30,000 samples,which is notably shorter than the 1026 s and 1558 s required for noninformative priors with 30,000 and 50,000 samples,respectively.These findingsunderscore the superior performance of the proposed approach in terms of both prediction accuracy and computational efficiency.These results demonstrate that the proposed method not only improves the predictive accuracy but also enhances the computational efficiency,enabling optimal parameter identificationwith reduced computational effort.This approach provides a robust and efficientframework for advancing dam safety assessments.展开更多
Storm-enhanced density(SED)and the tongue of ionization(TOI)are key ionospheric storm-time structures whose rapid evolution and fine-scale variability remain challenging to capture with conventional empirical high-lat...Storm-enhanced density(SED)and the tongue of ionization(TOI)are key ionospheric storm-time structures whose rapid evolution and fine-scale variability remain challenging to capture with conventional empirical high-latitude drivers.In this study,we examine the May 10–11,2024,superstorm using the Thermosphere–Ionosphere–Electrodynamics General Circulation Model(TIEGCM)with observation-constrained high-latitude forcing.Auroral precipitation parameters(energy flux and mean energy)are assimilated from a Defense Meteorological Satellite Program(DMSP)Special Sensor Ultraviolet Spectrographic Imager(SSUSI)using a multi-resolution Gaussian process(Lattice Kriging)approach,whereas high-latitude convection potentials are derived by assimilating Super Dual Auroral Radar Network(SuperDARN)observations with the Thomas and Shepherd(2018)model(TS18).For comparison,an additional simulation is performed using empirical models for both convection and auroral forcing.The results show that during the main phase of the May 10 storm,the data-driven simulation provides a more realistic depiction of the SED source region than does the empirical model run by capturing its rapid intensification more clearly and reproducing its spatial location and structural features with higher fidelity.These improvements lead to a more accurate representation of its poleward extension into the polar cap that develops into the TOI.Above the ionospheric F2 peak over the SED source region,SuperDARN-constrained potentials generate stronger and more localized E×B drifts that dominate plasma uplift and drive its transport into the polar cap,although neutral winds and downward ambipolar diffusion partially offset these effects.Below the F2 peak,neutral winds and photochemical processes play a major role in shaping the spatial extent and intensity of the SED and TOI.These results highlight the role of observation-constrained high-latitude drivers in representing ionosphere–thermosphere responses during extreme storms and suggest their relevance for improving physical interpretation and model performance.展开更多
The Wufeng–Longmaxi Formation derives its name from the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation,found in sequence in the Sichuan Basin.This formation hosts rich shale gas reservoir...The Wufeng–Longmaxi Formation derives its name from the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation,found in sequence in the Sichuan Basin.This formation hosts rich shale gas reservoirs,and its shale gas enrichment patterns are examined in this study using data from 1197 shale samples collected from 14 wells.Five basic and three key parameters,eight in all,are assessed for each sample.The five basic parameters include burial depth and the contents of four mineral types—quartz,clay,carbonate,and other minerals;the three key parameters,representing shale gas enrichment,are total organic carbon(TOC)content,porosity,and gas content.The SHapley Additive exPlanations(SHAP)analysis originated in game theory is used here in an interpretable machine learning framework,to address issues of heterogeneous data structure,noisy relationships,and multi-objective optimization.An evaluation of the ranking,contribution values,and conditions of changes for these parameters offers new quantitative insights into shale gas enrichment patterns.A quantitative analysis of the relationship between data-sets identifies the primary factors controlling TOC,porosity,and gas content of shale gas reservoirs.The results show that TOC and porosity jointly influence gas content;mineral content has a significant impact on both,TOC and porosity;and the burial depth governs porosity which,in turn,affects the conditions under which shale gas is preserved.Input parameter thresholds are also determined and provide a basis for the establishment of quantitative criteria to evaluate shale gas enrichment.The predictive accuracy of the model used in this study is significantly improved by the step-wise addition of two input parameters,namely TOC and porosity,separately and together.Thus,the game theory method in big data-driven analysis uses a combination of TOC and porosity to evaluate the gas content with encouraging results—suggesting that these are the key parameters that indicate source rock and reservoir properties.展开更多
The key challenge in the preparation of perovskite solar cells is to enhance the reproducibility of PSC manufacturing,particularly by better controlling multiple high-dimensional process parameters.This study proposes...The key challenge in the preparation of perovskite solar cells is to enhance the reproducibility of PSC manufacturing,particularly by better controlling multiple high-dimensional process parameters.This study proposes a machine learning(ML)approach to efficiently predict and analyze perovskite film fabrication processes.By evaluating five classic ML algorithms on 130 experimental data sets from blade-coating parameters,the Random Forest(RF)model was identified as the most effective,enabling rapid prediction of over 100,000 parameter sets in just 10 min-equivalent to 3 years of manual experimentation.The RF model demonstrated strong predictive accuracy,with an R^(2) close to 0.8.This approach led to the identification of optimal process parameter combinations,significantly improving the reproducibility of PSCs and reducing performance variance by approximately threefold,thereby advancing the development of scalable manufacturing processes.展开更多
This study is a comparative research based on corpus. This article compares China's English learners with English na?tive speakers about the use of "at last" and "in the end" from three aspects...This study is a comparative research based on corpus. This article compares China's English learners with English na?tive speakers about the use of "at last" and "in the end" from three aspects: frequency of use, location, semantic prosody. The study shows that the use of the two words are greatly different between China's English learners and English native speakers. In addition, this study discusses about causes of obvious differences and teaching enlightenments.展开更多
This study investigated the general situation of metalinguistic awareness of third language learners in Chinese universities.Data analyses showed that the level of metalinguistic awareness in those learners was signif...This study investigated the general situation of metalinguistic awareness of third language learners in Chinese universities.Data analyses showed that the level of metalinguistic awareness in those learners was significantly higher than that of second language learners.And learning a third language can improve metalinguistic awareness.展开更多
The paper discusses SL learners＇ lexical competence from O＇Connor＇s Five Steps of Vocabulary Acquisition Theory, Collins ＆ Loftus＇s Semantic Network Theory and Fay ＆ Cutler＇s Mental Lexicon Theory. From the dis...The paper discusses SL learners＇ lexical competence from O＇Connor＇s Five Steps of Vocabulary Acquisition Theory, Collins ＆ Loftus＇s Semantic Network Theory and Fay ＆ Cutler＇s Mental Lexicon Theory. From the discussion, the author finds that second language learners＇ lexical competence includes the following aspects： the ability to recall the words which are similar to the target words in spelling and pronunciation; the ability to recall the synonyms of the target words; the ability to recall the antonyms of the target words; and the ability to recall the related words which come together with the target words in a context. Meanwhile it advances some strategies to develop the corresponding competence.展开更多
It has long been in dispute about whether explicit grammar teaching is more effective in second language learning or implicit grammar teaching is.However,there are more than one factor to take into consideration while...It has long been in dispute about whether explicit grammar teaching is more effective in second language learning or implicit grammar teaching is.However,there are more than one factor to take into consideration while discussing which way is better for L2 learners.This short essay aims at depicting three respects concerning grammar teaching,namely learning context,language learners'beliefs and needs,and grammar instruction.When educators and practitioners try to adopt grammar instruction either implicitly or explicitly in L2 learners'writing development,they probably need to consider the above three factors and to find out the best way to produce more effective teaching results among their students.展开更多
基金supported by the National Natural Science Foundation of China(No.12372045)the National Key Research and the Development Program of China(Nos.2023YFC2205900,2023YFC2205901)。
文摘This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mission is disturbed by the measurement noise and the target adversarial behavior.To address these problems,a model-free Combined Adaptive-length Datadriven Predictive Controller(CADPC)is proposed.It consists of a separated subsystem identification method and a combined predictive control strategy.The subsystem identification method is composed of an adaptive data length,thereby reducing sensitivity to undetermined measurement noises and disturbances.Based on the subsystem identification,the combined predictive controller is established,reducing calculating resource.The stability of the CADPC is rigorously proven using the Input-to-State Stable(ISS)theorem and the small-gain theorem.Simulations demonstrate that CADPC effectively handles the model-free space robot post operation in the presence of significant disturbances,state measurement noise,and control input errors.It achieves improved steady-state accuracy,reduced steady-state control consumption,and minimized control input chattering.
文摘This study investigates the correlation between musical competence and English prosodic production as well as the associations among their internal components.Eighty Chinese EFL learners in college took the musical perception test,musical production test and English prosodic production test in sequence.In order to take a closer look at the prosodic performance,taking native English speakers as a reference,we also conducted an in-depth acoustic analysis of the English prosody produced by six cases in both high and low musical competence groups with the aid of Praat and ToBI.Our results indicate that students with high musical competence tend to outperform those with low musical competence in English prosodic production.However,musical perception competence seems to have a greater correlation with English prosodic competence than musical production competence.In addition,beat alignment or tempo(related to time and stress)could be the most associated component in musical competence with English prosody,while melody in music was double confirmed to be unhelpful.It was also spotted that cases with high musical competence performed more native-like patterns of phrase accent,boundary tones,intonational phrases as well as placement of stress.The results have important theoretical implications for the construct interpretation of musical competence,and also suggest that rhythmic perception training could be the most effective way to transfer music achievement to English speech prosody.
文摘This article provides a comprehensive analysis of the current feedback practices in Chinese college English as a foreign language(EFL)learners’writing classes,with a particular focus on understanding why students predominantly prefer teacher feedback to peer feedback.It identifies three major reasons shedding light on the underlying factors that make teacher feedback more appealing compared to other types of feedback.Considering the growing influence of online teaching,this study also proposes four practical solutions to enhance the effectiveness of feedback in the context of Chinese EFL learners’writing.The suggested solutions aim to address the challenges posed by online teaching while optimizing feedback mechanisms to support learners’writing development.Additionally,the author examines the potential of adopting a pluralistic feedback approach,which integrates teacher feedback,peer feedback,and online automated evaluation system to improve the overall feedback experience in the blended teaching environment.By combining these various feedback modes,the study explores their feasibility and effectiveness in enhancing the learning outcomes of Chinese EFL learners.The pluralistic feedback model is presented as a viable alternative that can address the limitations of relying solely on one-way teacher feedback,thus promoting a more dynamic and interactive learning process for college EFL learners in China.
文摘Online interactive learning plays a crucial role in improving online education quality.This grounded theory study examines:(1)what key factors shape EFL learners’online interactive learning,(2)how these factors form an empirically validated model,and(3)how they interact within this model,through systematic analysis of 9,207 discussion forum posts from a Chinese University MOOC platform.Results demonstrate that learning drive,course structure,teaching competence,interaction behavior,expected outcomes,and online learning context significantly influence EFL online interactive learning.The analysis reveals two key mechanisms:expected outcomes mediate the effects of learning drive(β=0.45),course structure,teaching competence,and interaction behavior(β=0.35)on learning outcomes,while online learning context moderates these relationships(β=0.25).Specifically,learning drive provides intrinsic/extrinsic motivation,whereas course structure,teaching competence,interaction behavior,and expected outcomes collectively enhance interaction quality and sustainability.These findings,derived through rigorous grounded theory methodology involving open,axial,and selective coding of large-scale interaction data,yield three key contributions:(1)a comprehensive theoretical model of EFL online learning dynamics,(2)empirical validation of mediation/moderation mechanisms,and(3)practical strategies for designing scaffolded interaction protocols and adaptive feedback systems.The study establishes that its theoretically saturated model(achieved after analyzing 7,366 posts with 1,841 verification cases)offers educators evidence-based approaches to optimize collaborative interaction in digital EFL environments.
文摘Language education has predominantly focused on classroom instruction and pedagogical strategies,yet the sociological aspects of learning-especially the family’s role-are often overlooked in English as a Foreign Language(EFL)contexts.This study explores how parental attitudes,support systems,and disciplinary approaches influence Turkish university students’oral fluency in English.While educators and curricula are frequently held accountable for low communicative competence,this paper posits that sociocultural factors originating from the home environment play a crucial role.Utilizing a qualitative-dominant mixed-methods design with 210 undergraduate EFL learners and 24 lecturers from four Turkish universities,data were gathered through questionnaires,interviews,and parental focus groups.Findings indicate that students with supportive and engaged parents exhibit greater self-efficacy,confidence,and linguistic agency in communication tasks.In contrast,those from indifferent or authoritarian families experience anxiety,low motivation,and stagnation in oral skills.Grounded in Bourdieu’s social capital theory,Bronfenbrenner’s ecological systems theory,and Coleman’s social context of learning,this study conceptualizes the family as an“invisible classroom”where linguistic habits,discipline,and cultural aspirations are cultivated.The paper concludes by proposing a Family-Engaged EFL Fluency Model(FE-EFM)that integrates learner development within a framework of sociological co-responsibility involving parents,educators,and institutions.
基金Chengdu City Philosophy and Social Sciences Research Center“artificial intelligence+urban communication”theory and Application Research Center Project“Chengdu real estate vertical market public opinion data visualization research”(Project No.RZCC2025017).
文摘This study integrates multiple sources of data(transaction data,policy text,public opinion data)with visualization techniques(such as heat maps,time-series trend charts,3D building brochures)to construct an analysis framework for the Chengdu real estate market.By using the Adaptive Neuro-Fuzzy Inference System(ANFIS)prediction model,spatial GIS(Geographic Information System analysis)analysis,and interactive dashboards,this study reveals market differentiation,policy impacts,and changes in demand structure,thereby providing decision support for the government,enterprises,and homebuyers.
基金supported in part by the National Natural Science Foundation of China,Grant/Award Number:62003267the Key Research and Development Program of Shaanxi Province,Grant/Award Number:2023-GHZD-33Open Project of the State Key Laboratory of Intelligent Game,Grant/Award Number:ZBKF-23-05。
文摘To address the issue of instability or even imbalance in the orientation and attitude control of quadrotor unmanned aerial vehicles(QUAVs)under random disturbances,this paper proposes a distributed antidisturbance data-driven event-triggered fusion control method,which achieves efficient fault diagnosis while suppressing random disturbances and mitigating communication conflicts within the QUAV swarm.First,the impact of random disturbances on the UAV swarm is analyzed,and a model for orientation and attitude control of QUAVs under stochastic perturbations is established,with the disturbance gain threshold determined.Second,a fault diagnosis system based on a high-gain observer is designed,constructing a fault gain criterion by integrating orientation and attitude information from QUAVs.Subsequently,a model-free dynamic linearization-based data modeling(MFDLDM)framework is developed using model-free adaptive control,which efficiently fits the nonlinear control model of the QUAV swarm while reducing temporal constraints on control data.On this basis,this paper constructs a distributed data-driven event-triggered controller based on the staggered communication mechanism,which consists of an equivalent QUAV controller and an event-triggered controller,and is able to reduce the communication conflicts while suppressing the influence of random interference.Finally,by incorporating random disturbances into the controller,comparative experiments and physical validations are conducted on the QUAV platforms,fully demonstrating the strong adaptability and robustness of the proposed distributed event-triggered fault-tolerant control system.
基金supported by the National Key R&D Program of China(Grant No.2023YFC3209504)Natural Science Foundation of Wuhan(Grant No.2024040801020271)the Fundamental Research Funds for Central Public Welfare Research Institutes(Grant No.CKSF2025718/YT).
文摘Wetting deformation in earth-rockfill dams is a critical factor influencingdam safety.Although numerous mathematical models have been developed to describe this phenomenon,most of them rely on empirical formulations and lack prior knowledge of model parameters,which is essential for Bayesian parameter inversion to enhance accuracy and reduce uncertainty.This study introduces a datadriven approach to establishing prior knowledge of earth-rockfill dams.Driving factors are utilized to determine the potential range of model parameters,and settlement changes within this range are calculated.The results are iteratively compared with actual monitoring data until the calculated range encompasses the observed data,thereby providing prior knowledge of the model parameters.The proposed method is applied to the right-bank earth-rockfilldam of Danjiangkou.Employing a Gibbs sample size of 30,000,the proposed method effectively calibrates the prior knowledge of the wetting model parameters,achieving a root mean square error(RMSE)of 5.18 mm for the settlement predictions.By comparison,the use of non-informative priors with sample sizes of 30,000 and 50,000 results in significantly larger RMSE values of 11.97 mm and 16.07 mm,respectively.Furthermore,the computational efficiencyof the proposed method is demonstrated by an inversion computation time of 902 s for 30,000 samples,which is notably shorter than the 1026 s and 1558 s required for noninformative priors with 30,000 and 50,000 samples,respectively.These findingsunderscore the superior performance of the proposed approach in terms of both prediction accuracy and computational efficiency.These results demonstrate that the proposed method not only improves the predictive accuracy but also enhances the computational efficiency,enabling optimal parameter identificationwith reduced computational effort.This approach provides a robust and efficientframework for advancing dam safety assessments.
基金The Shandong Provincial Natural Science Foundation(Grant No.ZR2022JQ18)supported this worksupported by the National Natural Science Foundation of China(NNFSC)Youth Program(Grant No.42304168)+1 种基金supported by the National Key R&D Program of China(Grant No.2022YFF0504400)the NNSFC(Grant Nos.42188101 and 42174210)。
文摘Storm-enhanced density(SED)and the tongue of ionization(TOI)are key ionospheric storm-time structures whose rapid evolution and fine-scale variability remain challenging to capture with conventional empirical high-latitude drivers.In this study,we examine the May 10–11,2024,superstorm using the Thermosphere–Ionosphere–Electrodynamics General Circulation Model(TIEGCM)with observation-constrained high-latitude forcing.Auroral precipitation parameters(energy flux and mean energy)are assimilated from a Defense Meteorological Satellite Program(DMSP)Special Sensor Ultraviolet Spectrographic Imager(SSUSI)using a multi-resolution Gaussian process(Lattice Kriging)approach,whereas high-latitude convection potentials are derived by assimilating Super Dual Auroral Radar Network(SuperDARN)observations with the Thomas and Shepherd(2018)model(TS18).For comparison,an additional simulation is performed using empirical models for both convection and auroral forcing.The results show that during the main phase of the May 10 storm,the data-driven simulation provides a more realistic depiction of the SED source region than does the empirical model run by capturing its rapid intensification more clearly and reproducing its spatial location and structural features with higher fidelity.These improvements lead to a more accurate representation of its poleward extension into the polar cap that develops into the TOI.Above the ionospheric F2 peak over the SED source region,SuperDARN-constrained potentials generate stronger and more localized E×B drifts that dominate plasma uplift and drive its transport into the polar cap,although neutral winds and downward ambipolar diffusion partially offset these effects.Below the F2 peak,neutral winds and photochemical processes play a major role in shaping the spatial extent and intensity of the SED and TOI.These results highlight the role of observation-constrained high-latitude drivers in representing ionosphere–thermosphere responses during extreme storms and suggest their relevance for improving physical interpretation and model performance.
基金funded by the Technical Development(Entrusted)Project of Science and Department of SINOPEC(Grant No.P23240-4)the National Natural Science Foundation of China(Grant Nos.42172165,42272143 and 2025ZD1403901-05)。
文摘The Wufeng–Longmaxi Formation derives its name from the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation,found in sequence in the Sichuan Basin.This formation hosts rich shale gas reservoirs,and its shale gas enrichment patterns are examined in this study using data from 1197 shale samples collected from 14 wells.Five basic and three key parameters,eight in all,are assessed for each sample.The five basic parameters include burial depth and the contents of four mineral types—quartz,clay,carbonate,and other minerals;the three key parameters,representing shale gas enrichment,are total organic carbon(TOC)content,porosity,and gas content.The SHapley Additive exPlanations(SHAP)analysis originated in game theory is used here in an interpretable machine learning framework,to address issues of heterogeneous data structure,noisy relationships,and multi-objective optimization.An evaluation of the ranking,contribution values,and conditions of changes for these parameters offers new quantitative insights into shale gas enrichment patterns.A quantitative analysis of the relationship between data-sets identifies the primary factors controlling TOC,porosity,and gas content of shale gas reservoirs.The results show that TOC and porosity jointly influence gas content;mineral content has a significant impact on both,TOC and porosity;and the burial depth governs porosity which,in turn,affects the conditions under which shale gas is preserved.Input parameter thresholds are also determined and provide a basis for the establishment of quantitative criteria to evaluate shale gas enrichment.The predictive accuracy of the model used in this study is significantly improved by the step-wise addition of two input parameters,namely TOC and porosity,separately and together.Thus,the game theory method in big data-driven analysis uses a combination of TOC and porosity to evaluate the gas content with encouraging results—suggesting that these are the key parameters that indicate source rock and reservoir properties.
基金Key Research and Development Program of Hubei Province,China(Grant No.2022BAA096)Zhejiang Provincial Natural Science Foundation of China(This material is based upon work funded by Zhejiang Provincial Natural Science Foundation of China under Grant No.LR25A020002)support of the Center for Materials Analysis and Characterization,Material Characterization Lab,and Nanofabrication Lab at Hubei University。
文摘The key challenge in the preparation of perovskite solar cells is to enhance the reproducibility of PSC manufacturing,particularly by better controlling multiple high-dimensional process parameters.This study proposes a machine learning(ML)approach to efficiently predict and analyze perovskite film fabrication processes.By evaluating five classic ML algorithms on 130 experimental data sets from blade-coating parameters,the Random Forest(RF)model was identified as the most effective,enabling rapid prediction of over 100,000 parameter sets in just 10 min-equivalent to 3 years of manual experimentation.The RF model demonstrated strong predictive accuracy,with an R^(2) close to 0.8.This approach led to the identification of optimal process parameter combinations,significantly improving the reproducibility of PSCs and reducing performance variance by approximately threefold,thereby advancing the development of scalable manufacturing processes.
文摘This study is a comparative research based on corpus. This article compares China's English learners with English na?tive speakers about the use of "at last" and "in the end" from three aspects: frequency of use, location, semantic prosody. The study shows that the use of the two words are greatly different between China's English learners and English native speakers. In addition, this study discusses about causes of obvious differences and teaching enlightenments.
文摘This study investigated the general situation of metalinguistic awareness of third language learners in Chinese universities.Data analyses showed that the level of metalinguistic awareness in those learners was significantly higher than that of second language learners.And learning a third language can improve metalinguistic awareness.
文摘The paper discusses SL learners＇ lexical competence from O＇Connor＇s Five Steps of Vocabulary Acquisition Theory, Collins ＆ Loftus＇s Semantic Network Theory and Fay ＆ Cutler＇s Mental Lexicon Theory. From the discussion, the author finds that second language learners＇ lexical competence includes the following aspects： the ability to recall the words which are similar to the target words in spelling and pronunciation; the ability to recall the synonyms of the target words; the ability to recall the antonyms of the target words; and the ability to recall the related words which come together with the target words in a context. Meanwhile it advances some strategies to develop the corresponding competence.
文摘It has long been in dispute about whether explicit grammar teaching is more effective in second language learning or implicit grammar teaching is.However,there are more than one factor to take into consideration while discussing which way is better for L2 learners.This short essay aims at depicting three respects concerning grammar teaching,namely learning context,language learners'beliefs and needs,and grammar instruction.When educators and practitioners try to adopt grammar instruction either implicitly or explicitly in L2 learners'writing development,they probably need to consider the above three factors and to find out the best way to produce more effective teaching results among their students.
