The distributed denial of service (DDoS) attack is one of the dangers in intrusion modes. It's difficult to defense and can cause serious damage to the system. Based on a careful study of the attack principles and...The distributed denial of service (DDoS) attack is one of the dangers in intrusion modes. It's difficult to defense and can cause serious damage to the system. Based on a careful study of the attack principles and characteristics, an object-oriented formalized description is presented, which contains a three-level framework and offers full specifications of all kinds of DDoS modes and their features and the relations between one another. Its greatest merit lies in that it contributes to analyzing, checking and judging DDoS. Now this formalized description has been used in a special IDS and it works very effectively.(展开更多
The goal of this paper is to take a further step towards an ontological approach for representing requirements information. The motivation for ontologies was discussed. The definitions of ontology and requirements ont...The goal of this paper is to take a further step towards an ontological approach for representing requirements information. The motivation for ontologies was discussed. The definitions of ontology and requirements ontology were given. Then, it presented a collection of informal terms, including four subject areas. It also discussed the formalization process of ontology. The underlying meta-ontology was determined, and the formalized requirements ontology was analyzed. This formal ontology is built to serve as a basis for requirements model. Finally, the implementation of software system was given.展开更多
The municipal bond program has been formally launched since the Ministry of Finance has issued two key regulations which formalize the municipal bond program in March,according to Linan Liu,senior strategist for Great...The municipal bond program has been formally launched since the Ministry of Finance has issued two key regulations which formalize the municipal bond program in March,according to Linan Liu,senior strategist for Greater China at Deutsche Bank.On March 12,the展开更多
The modifiedλ-differential Lie-Yamaguti algebras are considered,in which a modifiedλ-differential Lie-Yamaguti algebra consisting of a Lie-Yamaguti algebra and a modifiedλ-differential operator.First we introduce t...The modifiedλ-differential Lie-Yamaguti algebras are considered,in which a modifiedλ-differential Lie-Yamaguti algebra consisting of a Lie-Yamaguti algebra and a modifiedλ-differential operator.First we introduce the representation of modifiedλ-differential Lie-Yamaguti algebras.Furthermore,we establish the cohomology of a modifiedλ-differential Lie-Yamaguti algebra with coefficients in a representation.Finally,we investigate the one-parameter formal deformations and Abelian extensions of modifiedλ-differential Lie-Yamaguti algebras using the second cohomology group.展开更多
In this paper,we call a tuple consisting of 3-Lie algebra and a higher derivation on it a 3-LieHDer pair.We introduce a cohomology theory of 3-LieHDer pairs.Next,we interpret the second cohomology group as the space o...In this paper,we call a tuple consisting of 3-Lie algebra and a higher derivation on it a 3-LieHDer pair.We introduce a cohomology theory of 3-LieHDer pairs.Next,we interpret the second cohomology group as the space of all isomorphism classes of abelian extensions.Finally,we consider formal deformations of 3-LieHDer pairs that are governed by the cohomology with self-coefficient.展开更多
Smart learning environments have been considered as vital sources and essential needs in modern digital education systems.With the rapid proliferation of smart and assistive technologies,smart learning processes have ...Smart learning environments have been considered as vital sources and essential needs in modern digital education systems.With the rapid proliferation of smart and assistive technologies,smart learning processes have become quite convenient,comfortable,and financially affordable.This shift has led to the emergence of pervasive computing environments,where user’s intelligent behavior is supported by smart gadgets;however,it is becoming more challenging due to inconsistent behavior of Artificial intelligence(AI)assistive technologies in terms of networking issues,slow user responses to technologies and limited computational resources.This paper presents a context-aware predictive reasoning based formalism for smart learning environments that facilitates students in managing their academic as well as extra-curricular activities autonomously with limited human intervention.This system consists of a three-tier architecture including the acquisition of the contextualized information from the environment autonomously,modeling the system using Web Ontology Rule Language(OWL 2 RL)and Semantic Web Rule Language(SWRL),and perform reasoning to infer the desired goals whenever and wherever needed.For contextual reasoning,we develop a non-monotonic reasoning based formalism to reason with contextual information using rule-based reasoning.The focus is on distributed problem solving,where context-aware agents exchange information using rule-based reasoning and specify constraints to accomplish desired goals.To formally model-check and simulate the system behavior,we model the case study of a smart learning environment in the UPPAAL model checker and verify the desired properties in the model,such as safety,liveness and robust properties to reflect the overall correctness behavior of the system with achieving the minimum analysis time of 0.002 s and 34,712 KB memory utilization.展开更多
This study sought to analyze the occupational habits of immigrant workers in the formal Brazilian labor market from a sociological perspective.It was understood that a study on occupation should observe professional a...This study sought to analyze the occupational habits of immigrant workers in the formal Brazilian labor market from a sociological perspective.It was understood that a study on occupation should observe professional and employment history,which may include an analysis over time of workers in the same profession or in periods of professional mobility.In order to understand occupational trajectories and related aspects,this study used data that were collected through semi-structured interviews and surveys with immigrant workers who were employed in the Brazilian formal labor market.The interviews and surveys revealed a strong polarization among the immigrant workers present in Brazil-while a small part holds highly skilled occupations,the majority participate at the base of the productivity hierarchy.展开更多
On 20 April 1994,China made its first o!cial full-function connection to the World Wide Web through a 64-kilobyte international leased line,marking the country’s formal entry into the global digital age.The year 2024...On 20 April 1994,China made its first o!cial full-function connection to the World Wide Web through a 64-kilobyte international leased line,marking the country’s formal entry into the global digital age.The year 2024 marked the 30th anniversary of the country’s entry into the internet era.展开更多
Cambodia and China have long enjoyed a close relationship grounded in centuries of historical,cultural,and political ties.From their early connections in the 13th Century to today’s multifaceted partnership,the bond ...Cambodia and China have long enjoyed a close relationship grounded in centuries of historical,cultural,and political ties.From their early connections in the 13th Century to today’s multifaceted partnership,the bond between these two nations has been built on mutual respect and cooperation,fortified by economic collaboration and a profound connection between their peoples.Since the formal establishment of diplomatic ties in 1958,Cambodia and China have fostered an enduring“ironclad”friendship that weathered challenges and adapted to the everchanging global dynamics.展开更多
Following the groundbreaking introduction of the Transformer architecture in 2017,the development of Large Language Models(LLMs)formally commenced.In May 2020,Chat GPT-3,with over one hundred billion parameters,entere...Following the groundbreaking introduction of the Transformer architecture in 2017,the development of Large Language Models(LLMs)formally commenced.In May 2020,Chat GPT-3,with over one hundred billion parameters,entered the public eye,marking a significant milestone in LLM advancement.展开更多
When China and Singapore exchanged formal handshakes in 1990,few could have imagined that 35 years later,a Data Science undergraduate named Hu Yunxin would be happily counting hawker-centre noodles while memorizing re...When China and Singapore exchanged formal handshakes in 1990,few could have imagined that 35 years later,a Data Science undergraduate named Hu Yunxin would be happily counting hawker-centre noodles while memorizing regression formulas along Clementi Road.Yet it is precisely these small,personal stories that breathe life into grand diplomatic milestones.In celebration of the anniversary,I spoke with Yunxin—freshly returned from her first year at the National University of Singapore(NUS)—to discover how the Lion City looks through Chinese eyes.展开更多
Preserving formal style in neural machine translation (NMT) is essential, yet often overlooked as an optimization objective of the training processes. This oversight can lead to translations that, though accurate, lac...Preserving formal style in neural machine translation (NMT) is essential, yet often overlooked as an optimization objective of the training processes. This oversight can lead to translations that, though accurate, lack formality. In this paper, we propose how to improve NMT formality with large language models (LLMs), which combines the style transfer and evaluation capabilities of an LLM and the high-quality translation generation ability of NMT models to improve NMT formality. The proposed method (namely INMTF) encompasses two approaches. The first involves a revision approach using an LLM to revise the NMT-generated translation, ensuring a formal translation style. The second approach employs an LLM as a reward model for scoring translation formality, and then uses reinforcement learning algorithms to fine-tune the NMT model to maximize the reward score, thereby enhancing the formality of the generated translations. Considering the substantial parameter size of LLMs, we also explore methods to reduce the computational cost of INMTF. Experimental results demonstrate that INMTF significantly outperforms baselines in terms of translation formality and translation quality, with an improvement of +9.19 style accuracy points in the German-to-English task and +2.16 COMET score in the Russian-to-English task. Furthermore, our work demonstrates the potential of integrating LLMs within NMT frameworks to bridge the gap between NMT outputs and the formality required in various real-world translation scenarios.展开更多
With the assistance of Stroh formalism,the general solutions satisfying the basic laws of linear elastic theory are written in complex variable forms.To analyze the fracture behavior of two-dimensional decagonal piezo...With the assistance of Stroh formalism,the general solutions satisfying the basic laws of linear elastic theory are written in complex variable forms.To analyze the fracture behavior of two-dimensional decagonal piezoelectric quasicrystals,an elliptical hole model under different boundary conditions is established.The analytical expressions of generalized stress intensity factors(GSIFs)are obtained,respectively,for four general cases:a Griffith crack with generalized remote uniform loading,arbitrary loading on the crack surface,concentrated loading at any position of the crack surface,and multiple collinear periodic cracks under uniform loading at infinity.Numerical examples are given,and the effects of crack length,loading position,loading condition,and crack period on GSIFs are discussed.The derived analytical solutions of cracks play a significant role in understanding the phonon-phason and electromechanical coupled behavior in quasicrystals,and they also serve as criteria for fracture analysis.展开更多
This study aims to present exact multi-field coupling modeling and analysis of a simply-supported rectangular piezoelectric semiconductor(PSC)plate.Under the linear assumption of drift-diffusion current for a small el...This study aims to present exact multi-field coupling modeling and analysis of a simply-supported rectangular piezoelectric semiconductor(PSC)plate.Under the linear assumption of drift-diffusion current for a small electron concentration perturbation,the governing equations are solved by extending the classical Stroh formalism to involve all the physical fields of PSCs.The general solutions are obtained and then utilized to analyze three-dimensional(3D)problems of static deformation and free vibration of the PSC plate.To investigate the multi-physics interactions along the plate thickness,the distribution forms of electromechanical fields and electron concentration perturbation are given exactly,which are helpful for the development of the PSC plate theory.The differences between the PSC and purely piezoelectric as well as purely elastic counterparts are emphasized,in the context of evaluating the material performances with changing initial electron concentration.The results demonstrate that the PSC coupling exists only within a specific range of the initial electron concentration,where it exhibits a transition from the piezoelectric characteristics to the elastic ones.In addition,the dependence of coupling behaviors on the plate thickness is clarified.These results can not only be benchmarks in the development of PSC plate theories or other numerical methods,but also be guidance for the design of plate-based PSC devices.展开更多
This paper investigates control synthesis for motion planning under conditions of uncertainty,specifically in robot motion and environmental properties,which are modeled using a probabilistic labeled Markov decision p...This paper investigates control synthesis for motion planning under conditions of uncertainty,specifically in robot motion and environmental properties,which are modeled using a probabilistic labeled Markov decision process(PL-MDP).To address this,a model-free reinforcement learning(RL)approach is designed to produce a finite-memory control policy that meets complex tasks specified by linear temporal logic(LTL)formulas.Recognizing the presence of uncertainties and potentially conflicting objectives,this study centers on addressing infeasible LTL specifications.A relaxed LTL constraint enables the agent to adapt its motion plan,allowing for partial satisfaction by accounting for necessary task violations.Additionally,a new automaton structure is introduced to increase the density of accepting rewards,facilitating deterministic policy outcomes.The proposed RL framework is rigorously analyzed and prioritizes two key objectives:(1)satisfying the acceptance condition of the relaxed product MDP,and(2)minimizing long-term violation costs.Simulation and experimental results are presented to demonstrate the framework’s effectiveness and robustness.展开更多
Phonon quasiparticles and their anharmonic interactions govern heat transport in insulators.Accurate characterization of phonon frequencies and linewidths,especially beyond the quasiparticle approximation,is essential...Phonon quasiparticles and their anharmonic interactions govern heat transport in insulators.Accurate characterization of phonon frequencies and linewidths,especially beyond the quasiparticle approximation,is essential for understanding anharmonic effects and lattice thermal conductivity.Here,we investigate the anharmonic lattice dynamics and phonon transport in crystalline copper halides CuBiI4 using the self-consistent phonon theory,combined with the Wigner transport formalism and the quasi-harmonic Green–Kubo method.Results show that the three-phonon bubble self-energy substantially renormalizes the phonon dispersion,inducing strong modedependent broadening.Depending on the strength of the anharmonic scattering,phonons exhibit particle-like,wave-like,or overdamped transport characteristics,with broadened states contributing additional coherent thermal transport channels.We establish a consistent description of the overdamped phonon self-energy and advance the microscopic understanding of the strongly anharmonic phonon thermal transport in CuBiI4.Overdamped phonon modes significantly hinder the lattice thermal transport by reducing phonon lifetimes.However,the still well-defined phonon dispersions mitigate carrier scattering induced by the local structural disorder.Anisotropic electrical transport properties are obtained by considering polar and non-polar electroacoustic coupling and ionized impurity scattering mechanisms.Upon electron doping,the thermoelectric figure of merit of n-type CuBiI4 reaches 2.25 at 800 K.展开更多
The polaron problem is a very old problem in condensed matter physics that dates back to the thirties,but still remains largely unsolved today,especially when electron–electron interaction is taken into consideration...The polaron problem is a very old problem in condensed matter physics that dates back to the thirties,but still remains largely unsolved today,especially when electron–electron interaction is taken into consideration.The presence of both electron–electron and electron–phonon interactions in the problem invalidates most existing numerical methods,which are either computationally too expensive or simply intractable.The continuous-time quantum Monte Carlo(CTQMC)methods could tackle this problem,but they are only effective on the imaginarytime axis.In this work,we present a method based on tensor networks and the path integral formalism to solve polaron impurity problems.As both the electron and phonon baths can be integrated out via the Feynman–Vernon influence functional in the path integral formalism,our method is free of bath discretization error.It can also flexibly work on imaginary time,Keldysh contour,and L-shaped Kadanoff contour.In addition,our method can naturally resolve several long-existing challenges:(i)non-diagonal hybridization function;(ii)measuring multi-time correlations beyond single-particle Green’s functions.We demonstrate the effectiveness and accuracy of our method with extensive numerical examples against analytic solutions,exact diagonalization,and CTQMC.We also perform full-fledged real-time calculations that have never been done before to our knowledge,which could serve as a benchmarking baseline for future method developments.展开更多
What laws do the universe naturally operate according to?What should be the logical foundation of the human real world?This is a foundational and fundamental issue that humans have always wanted to clarify.From Thales...What laws do the universe naturally operate according to?What should be the logical foundation of the human real world?This is a foundational and fundamental issue that humans have always wanted to clarify.From Thales to philosophers such as Socrates,Plato,and Aristotle,ancient Greece achieved the origin and development of philosophy;Later,Descartes,Hume,Kant,Hegel,Nietzsche,and others explored new fields and concepts;Philosophers such as Husserl,Sartre,Russell,Wittgenstein,and Derrida left a profound mark in the 20th century.The emergence of a worldview emerged in the ancient Indian Vedas,and later in the religious and philosophical work The Upanishads,there was a discourse on the entities of"Brahma"and"I",which gave rise to the idea of"Advaita"in later generations.The Book of Changes was born in ancient China,along with major academic schools such as Taoism,Confucianism,Legalism,and Mohism.Later,Buddhist thought was integrated;With the Eastern ideas of yin and yang,the Doctrine of the Mean,harmony,and the ultimate goodness,I have integrated Eastern and Western historical philosophies,modern physics,and classical logic theories in my thinking on the principle of cosmic paradox,proposing a new perspective of understanding the essence of the universe and its natural logical relationship structure using the principle of paradox as the law of cosmic operation.The theoretical exploration and discussion of the dual nature relationship of"non-contradiction"and"contradiction"in the"first contradiction"relationship of things in the universe,that is,the identity of the universe is a self-contradictory overall transformation process;Attempting to reveal the paradoxical relationship of the universe from a new perspective in modern science,philosophy,and logic,striving to have a beneficial impact on the exploration and practical application of sustainable human survival and development models in the future.展开更多
文摘The distributed denial of service (DDoS) attack is one of the dangers in intrusion modes. It's difficult to defense and can cause serious damage to the system. Based on a careful study of the attack principles and characteristics, an object-oriented formalized description is presented, which contains a three-level framework and offers full specifications of all kinds of DDoS modes and their features and the relations between one another. Its greatest merit lies in that it contributes to analyzing, checking and judging DDoS. Now this formalized description has been used in a special IDS and it works very effectively.(
基金HighTechnologyResearch andDevelopment Program"863" (No.2 0 0 2 AA4114 2 0 )National NaturalScienceFoundation of China (No.60 3 740 71)
文摘The goal of this paper is to take a further step towards an ontological approach for representing requirements information. The motivation for ontologies was discussed. The definitions of ontology and requirements ontology were given. Then, it presented a collection of informal terms, including four subject areas. It also discussed the formalization process of ontology. The underlying meta-ontology was determined, and the formalized requirements ontology was analyzed. This formal ontology is built to serve as a basis for requirements model. Finally, the implementation of software system was given.
文摘The municipal bond program has been formally launched since the Ministry of Finance has issued two key regulations which formalize the municipal bond program in March,according to Linan Liu,senior strategist for Greater China at Deutsche Bank.On March 12,the
基金National Natural Science Foundation of China(12161013)Research Projects of Guizhou University of Commerce in 2024。
文摘The modifiedλ-differential Lie-Yamaguti algebras are considered,in which a modifiedλ-differential Lie-Yamaguti algebra consisting of a Lie-Yamaguti algebra and a modifiedλ-differential operator.First we introduce the representation of modifiedλ-differential Lie-Yamaguti algebras.Furthermore,we establish the cohomology of a modifiedλ-differential Lie-Yamaguti algebra with coefficients in a representation.Finally,we investigate the one-parameter formal deformations and Abelian extensions of modifiedλ-differential Lie-Yamaguti algebras using the second cohomology group.
基金Supported by the National Natural Science Foundation of China(Grant No.12161013)the Basic Research Program(Natural Science)of Guizhou Province(Grant No.ZK[2023]025).
文摘In this paper,we call a tuple consisting of 3-Lie algebra and a higher derivation on it a 3-LieHDer pair.We introduce a cohomology theory of 3-LieHDer pairs.Next,we interpret the second cohomology group as the space of all isomorphism classes of abelian extensions.Finally,we consider formal deformations of 3-LieHDer pairs that are governed by the cohomology with self-coefficient.
基金supported by the National Research Foundation(NRF),Republic of Korea,under project BK21 FOUR(4299990213939).
文摘Smart learning environments have been considered as vital sources and essential needs in modern digital education systems.With the rapid proliferation of smart and assistive technologies,smart learning processes have become quite convenient,comfortable,and financially affordable.This shift has led to the emergence of pervasive computing environments,where user’s intelligent behavior is supported by smart gadgets;however,it is becoming more challenging due to inconsistent behavior of Artificial intelligence(AI)assistive technologies in terms of networking issues,slow user responses to technologies and limited computational resources.This paper presents a context-aware predictive reasoning based formalism for smart learning environments that facilitates students in managing their academic as well as extra-curricular activities autonomously with limited human intervention.This system consists of a three-tier architecture including the acquisition of the contextualized information from the environment autonomously,modeling the system using Web Ontology Rule Language(OWL 2 RL)and Semantic Web Rule Language(SWRL),and perform reasoning to infer the desired goals whenever and wherever needed.For contextual reasoning,we develop a non-monotonic reasoning based formalism to reason with contextual information using rule-based reasoning.The focus is on distributed problem solving,where context-aware agents exchange information using rule-based reasoning and specify constraints to accomplish desired goals.To formally model-check and simulate the system behavior,we model the case study of a smart learning environment in the UPPAAL model checker and verify the desired properties in the model,such as safety,liveness and robust properties to reflect the overall correctness behavior of the system with achieving the minimum analysis time of 0.002 s and 34,712 KB memory utilization.
文摘This study sought to analyze the occupational habits of immigrant workers in the formal Brazilian labor market from a sociological perspective.It was understood that a study on occupation should observe professional and employment history,which may include an analysis over time of workers in the same profession or in periods of professional mobility.In order to understand occupational trajectories and related aspects,this study used data that were collected through semi-structured interviews and surveys with immigrant workers who were employed in the Brazilian formal labor market.The interviews and surveys revealed a strong polarization among the immigrant workers present in Brazil-while a small part holds highly skilled occupations,the majority participate at the base of the productivity hierarchy.
文摘On 20 April 1994,China made its first o!cial full-function connection to the World Wide Web through a 64-kilobyte international leased line,marking the country’s formal entry into the global digital age.The year 2024 marked the 30th anniversary of the country’s entry into the internet era.
文摘Cambodia and China have long enjoyed a close relationship grounded in centuries of historical,cultural,and political ties.From their early connections in the 13th Century to today’s multifaceted partnership,the bond between these two nations has been built on mutual respect and cooperation,fortified by economic collaboration and a profound connection between their peoples.Since the formal establishment of diplomatic ties in 1958,Cambodia and China have fostered an enduring“ironclad”friendship that weathered challenges and adapted to the everchanging global dynamics.
文摘Following the groundbreaking introduction of the Transformer architecture in 2017,the development of Large Language Models(LLMs)formally commenced.In May 2020,Chat GPT-3,with over one hundred billion parameters,entered the public eye,marking a significant milestone in LLM advancement.
文摘When China and Singapore exchanged formal handshakes in 1990,few could have imagined that 35 years later,a Data Science undergraduate named Hu Yunxin would be happily counting hawker-centre noodles while memorizing regression formulas along Clementi Road.Yet it is precisely these small,personal stories that breathe life into grand diplomatic milestones.In celebration of the anniversary,I spoke with Yunxin—freshly returned from her first year at the National University of Singapore(NUS)—to discover how the Lion City looks through Chinese eyes.
文摘Preserving formal style in neural machine translation (NMT) is essential, yet often overlooked as an optimization objective of the training processes. This oversight can lead to translations that, though accurate, lack formality. In this paper, we propose how to improve NMT formality with large language models (LLMs), which combines the style transfer and evaluation capabilities of an LLM and the high-quality translation generation ability of NMT models to improve NMT formality. The proposed method (namely INMTF) encompasses two approaches. The first involves a revision approach using an LLM to revise the NMT-generated translation, ensuring a formal translation style. The second approach employs an LLM as a reward model for scoring translation formality, and then uses reinforcement learning algorithms to fine-tune the NMT model to maximize the reward score, thereby enhancing the formality of the generated translations. Considering the substantial parameter size of LLMs, we also explore methods to reduce the computational cost of INMTF. Experimental results demonstrate that INMTF significantly outperforms baselines in terms of translation formality and translation quality, with an improvement of +9.19 style accuracy points in the German-to-English task and +2.16 COMET score in the Russian-to-English task. Furthermore, our work demonstrates the potential of integrating LLMs within NMT frameworks to bridge the gap between NMT outputs and the formality required in various real-world translation scenarios.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272402,12102458,and 11972365)the China Agricultural University Education Foundation(No.1101-2412001).
文摘With the assistance of Stroh formalism,the general solutions satisfying the basic laws of linear elastic theory are written in complex variable forms.To analyze the fracture behavior of two-dimensional decagonal piezoelectric quasicrystals,an elliptical hole model under different boundary conditions is established.The analytical expressions of generalized stress intensity factors(GSIFs)are obtained,respectively,for four general cases:a Griffith crack with generalized remote uniform loading,arbitrary loading on the crack surface,concentrated loading at any position of the crack surface,and multiple collinear periodic cracks under uniform loading at infinity.Numerical examples are given,and the effects of crack length,loading position,loading condition,and crack period on GSIFs are discussed.The derived analytical solutions of cracks play a significant role in understanding the phonon-phason and electromechanical coupled behavior in quasicrystals,and they also serve as criteria for fracture analysis.
基金Project supported by the National Natural Science Foundation of China(Nos.U21A20430 and 12472155)the Science Research Project of Hebei Education Department of China(No.BJK2022055)+2 种基金the“333 Talents Project”of Hebei Province of China(No.C20231111)the Natural Science Foundation of Hebei Province of China(Nos.A2024210002 and A2023210064)the S&T Program of Hebei Province of China(No.225676162GH)。
文摘This study aims to present exact multi-field coupling modeling and analysis of a simply-supported rectangular piezoelectric semiconductor(PSC)plate.Under the linear assumption of drift-diffusion current for a small electron concentration perturbation,the governing equations are solved by extending the classical Stroh formalism to involve all the physical fields of PSCs.The general solutions are obtained and then utilized to analyze three-dimensional(3D)problems of static deformation and free vibration of the PSC plate.To investigate the multi-physics interactions along the plate thickness,the distribution forms of electromechanical fields and electron concentration perturbation are given exactly,which are helpful for the development of the PSC plate theory.The differences between the PSC and purely piezoelectric as well as purely elastic counterparts are emphasized,in the context of evaluating the material performances with changing initial electron concentration.The results demonstrate that the PSC coupling exists only within a specific range of the initial electron concentration,where it exhibits a transition from the piezoelectric characteristics to the elastic ones.In addition,the dependence of coupling behaviors on the plate thickness is clarified.These results can not only be benchmarks in the development of PSC plate theories or other numerical methods,but also be guidance for the design of plate-based PSC devices.
基金supported by the National Natural Science Foundation of China under Grant 62173314.
文摘This paper investigates control synthesis for motion planning under conditions of uncertainty,specifically in robot motion and environmental properties,which are modeled using a probabilistic labeled Markov decision process(PL-MDP).To address this,a model-free reinforcement learning(RL)approach is designed to produce a finite-memory control policy that meets complex tasks specified by linear temporal logic(LTL)formulas.Recognizing the presence of uncertainties and potentially conflicting objectives,this study centers on addressing infeasible LTL specifications.A relaxed LTL constraint enables the agent to adapt its motion plan,allowing for partial satisfaction by accounting for necessary task violations.Additionally,a new automaton structure is introduced to increase the density of accepting rewards,facilitating deterministic policy outcomes.The proposed RL framework is rigorously analyzed and prioritizes two key objectives:(1)satisfying the acceptance condition of the relaxed product MDP,and(2)minimizing long-term violation costs.Simulation and experimental results are presented to demonstrate the framework’s effectiveness and robustness.
基金supported by the National Natural Science Foundation of China(Grant Nos.12574028,U2330104,and 12074381)Guang-dong Basic and Applied Basic Research Foundation(Grant No.2024A1515010484)。
文摘Phonon quasiparticles and their anharmonic interactions govern heat transport in insulators.Accurate characterization of phonon frequencies and linewidths,especially beyond the quasiparticle approximation,is essential for understanding anharmonic effects and lattice thermal conductivity.Here,we investigate the anharmonic lattice dynamics and phonon transport in crystalline copper halides CuBiI4 using the self-consistent phonon theory,combined with the Wigner transport formalism and the quasi-harmonic Green–Kubo method.Results show that the three-phonon bubble self-energy substantially renormalizes the phonon dispersion,inducing strong modedependent broadening.Depending on the strength of the anharmonic scattering,phonons exhibit particle-like,wave-like,or overdamped transport characteristics,with broadened states contributing additional coherent thermal transport channels.We establish a consistent description of the overdamped phonon self-energy and advance the microscopic understanding of the strongly anharmonic phonon thermal transport in CuBiI4.Overdamped phonon modes significantly hinder the lattice thermal transport by reducing phonon lifetimes.However,the still well-defined phonon dispersions mitigate carrier scattering induced by the local structural disorder.Anisotropic electrical transport properties are obtained by considering polar and non-polar electroacoustic coupling and ionized impurity scattering mechanisms.Upon electron doping,the thermoelectric figure of merit of n-type CuBiI4 reaches 2.25 at 800 K.
基金supported by the National Natural Science Foundation of China(Grant No.12104328)。
文摘The polaron problem is a very old problem in condensed matter physics that dates back to the thirties,but still remains largely unsolved today,especially when electron–electron interaction is taken into consideration.The presence of both electron–electron and electron–phonon interactions in the problem invalidates most existing numerical methods,which are either computationally too expensive or simply intractable.The continuous-time quantum Monte Carlo(CTQMC)methods could tackle this problem,but they are only effective on the imaginarytime axis.In this work,we present a method based on tensor networks and the path integral formalism to solve polaron impurity problems.As both the electron and phonon baths can be integrated out via the Feynman–Vernon influence functional in the path integral formalism,our method is free of bath discretization error.It can also flexibly work on imaginary time,Keldysh contour,and L-shaped Kadanoff contour.In addition,our method can naturally resolve several long-existing challenges:(i)non-diagonal hybridization function;(ii)measuring multi-time correlations beyond single-particle Green’s functions.We demonstrate the effectiveness and accuracy of our method with extensive numerical examples against analytic solutions,exact diagonalization,and CTQMC.We also perform full-fledged real-time calculations that have never been done before to our knowledge,which could serve as a benchmarking baseline for future method developments.
文摘What laws do the universe naturally operate according to?What should be the logical foundation of the human real world?This is a foundational and fundamental issue that humans have always wanted to clarify.From Thales to philosophers such as Socrates,Plato,and Aristotle,ancient Greece achieved the origin and development of philosophy;Later,Descartes,Hume,Kant,Hegel,Nietzsche,and others explored new fields and concepts;Philosophers such as Husserl,Sartre,Russell,Wittgenstein,and Derrida left a profound mark in the 20th century.The emergence of a worldview emerged in the ancient Indian Vedas,and later in the religious and philosophical work The Upanishads,there was a discourse on the entities of"Brahma"and"I",which gave rise to the idea of"Advaita"in later generations.The Book of Changes was born in ancient China,along with major academic schools such as Taoism,Confucianism,Legalism,and Mohism.Later,Buddhist thought was integrated;With the Eastern ideas of yin and yang,the Doctrine of the Mean,harmony,and the ultimate goodness,I have integrated Eastern and Western historical philosophies,modern physics,and classical logic theories in my thinking on the principle of cosmic paradox,proposing a new perspective of understanding the essence of the universe and its natural logical relationship structure using the principle of paradox as the law of cosmic operation.The theoretical exploration and discussion of the dual nature relationship of"non-contradiction"and"contradiction"in the"first contradiction"relationship of things in the universe,that is,the identity of the universe is a self-contradictory overall transformation process;Attempting to reveal the paradoxical relationship of the universe from a new perspective in modern science,philosophy,and logic,striving to have a beneficial impact on the exploration and practical application of sustainable human survival and development models in the future.
