We propose an experimental scheme for implementing the optimal 1 → 3 real state cloning via linear optical elements. This method relies on one polarized qubit and two location qubits and is feasible with current expe...We propose an experimental scheme for implementing the optimal 1 → 3 real state cloning via linear optical elements. This method relies on one polarized qubit and two location qubits and is feasible with current experimental technology.展开更多
The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliab...The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliability. Based on the analysis of the characteristics of real-time embedded software, the formal method is introduced into the real-time embedded software testing field and the real-time extended finite state machine （RT-EFSM） model is studied firstly. Then, the time zone division method of real-time embedded system is presented and the definition and description methods of time-constrained transition equivalence class （timeCTEC） are presented. Furthermore, the approaches of the testing sequence and test case generation are put forward. Finally, the proposed method is applied to a typical avionics real- time embedded software testing practice and the examples of the timeCTEC, testing sequences and test cases are given. With the analysis of the testing result, the application verification shows that the proposed method can effectively describe the real-time embedded software state transition characteristics and real-time requirements and play the advantages of the formal methods in accuracy, effectiveness and the automation supporting. Combined with the testing platform, the real-time, closed loop and automated simulation testing for real-time embedded software can be realized effectively.展开更多
This paper presents a model specifying requirements of real-time systems. Different from existing researches, this model mainly uses rules and templates to represent hierarchical FSMs (Finite State Machine). In this m...This paper presents a model specifying requirements of real-time systems. Different from existing researches, this model mainly uses rules and templates to represent hierarchical FSMs (Finite State Machine). In this model, one rule corresponds to one state transition of FSM and one template corresponds to one FSM. Rules and information with respect to a FSM can be written in a template. So templates include not only state diagrams, but also information that can not be described by FSM, such as performance requirements. The specification using this model consists of a collection of templates and it is easy for users to understand and to review. After introduced the related researches and principles of the model, this paper specifies requirements of a real-time system with this model, and discusses characters of this model in the end.展开更多
In relativistic mechanics the time-like vector characterize the motion in spacetime with speed faster than the speed of light in vacuum c in which the line element ds2=c2dt2-dx2-dx2-dz2 is less than zero (where is inf...In relativistic mechanics the time-like vector characterize the motion in spacetime with speed faster than the speed of light in vacuum c in which the line element ds2=c2dt2-dx2-dx2-dz2 is less than zero (where is infinitesimal change in time, and are infinitesimal change in space), thus the time in relativistic mechanics can instantaneously flow [1], however in quantum mechanics although the time is treated as unobservable parameter (without any Hermitian observable operator have engine-value equivalent to time) any two physical quantity described by two non-commuting observable operatorsand fulfill , the knowledge of one immediately produce the knowledge of the other [2], thus in quantum mechanics if two particles interacted in finite temporal epoch and then separated in space the gaining of knowledge by the local measurement of physical quantity runs on one them (for example the measurement of spin direction of one particle using Stern-Gerlach experiment) immediately produce the knowledge of the complementary physical quantity of the other particle (for example the opposite spin direction of the other particle), this simply called quantum entanglement the concept that so much advanced after publication of the Jon Bell’s 1964 celebrated paper [3] in which he illustrated that we can add parameters to quantum mechanics to determine the results of individual measurements, without changing the statistical predictions, and then he conclude “there must be a mechanism whereby the setting of one measuring device can influence the reading of another instrument, however remote. Moreover, the signal involved must propagate instantaneously so that such a theory could not be Lorentz invariant”. The question now what these signals that can propagate instantaneously? The answer in this paper will be the time signals field which is defined for each constituent matter particle M and at each space point P as the measure of the total length of all occupation and leaving epochs of P by M which is representing a sequence function compactly supported only at the space point occupied by it and indexed by the number of occupation epochs of P by M, thus the flow of this time signal field from the far future to near future through the present to the near past to the far past inferable by the flow of matter particles constituting the system(such as sun, moon earth and clocks hands). Thus the present will represent in this paper a local absolute feature of time signals field defined at each space point as the set of all occupation epochs of it by matter particle, however the past and future will represent relativistic non-local features of the time signal field defined at each space point as a set of all leaving epochs between each two sequential occupation epochs, so the future after one occupation epoch is representing a past of the next one. Thus according to current representation of time, the two Mc-Taggard’s A and B series of time [4] will exist together as temporal set and then the time is real, the A-series in current theory is a set of all occupation and leaving epochs of space point by the matter particle that is consisting of the present, past and future epochs, and the B-series is the set of all leaving epochs of space points between each two sequential occupation epochs which are taking position before or after the discrete occupation epochs between them and then before or after each other.展开更多
This paper investigates the positive real control problem for uncertain descriptor systems. The parametric uncertainty is assumed to be norm bounded. Firstly, for the nominal system, a new positive real characterizati...This paper investigates the positive real control problem for uncertain descriptor systems. The parametric uncertainty is assumed to be norm bounded. Firstly, for the nominal system, a new positive real characterization is given, which is expressed by a strict linear matrix mequality（LMI） without equality constraints. Secondly, for the uncertain system, necessary and sufficient conditions for the solvability of the positive real control problem are derived. Based on these conditions a state feedback law is obtained, which renders the resultant closed-loop system robustly positive real.展开更多
In spite of the inherent difficulty, reproducing the exact structure of real flows is a critically important issue in many fields, such as weather forecasting or feedback flow control. In order to obtain information o...In spite of the inherent difficulty, reproducing the exact structure of real flows is a critically important issue in many fields, such as weather forecasting or feedback flow control. In order to obtain information on real flows, extensive studies have been carried out on methodology to integrate measurement and simulation, for example, the four-dimensional variational data assimilation method (4D-Var) or the state estimator such as the Kalman filter or the state observer. Measurement-integrated (MI) simulation is a state observer in which a computational fluid dynamics (CFD) scheme is used as a mathematical model of the physical system instead of a small dimensional linear dynamical system usually used in state observers. A large dimensional nonlinear CFD model makes it possible to accurately reproduce real flows for properly designed feedback signals. This review article surveys the theoretical formulations and applications of MI simulation. Formulations of MI simulation are presented, including governing equations of a flow field observer, those of a linearized error dynamics describing the convergence of the observer, and stabilization of the numerical scheme, which is important in implementation of MI simulation. Applications of MI simulation are presented ranging from fundamental turbulent flows in pipes and Karman vortices in a wind tunnel to clinical application in diagnosis of blood flows in a human body.展开更多
We consider a multi server and multichannel real-time system with identical servers (e.g. unmanned aerial vehicles, machine controllers, etc.) that provide services for requests of real-time jobs arriving via several ...We consider a multi server and multichannel real-time system with identical servers (e.g. unmanned aerial vehicles, machine controllers, etc.) that provide services for requests of real-time jobs arriving via several different channels (e.g. surveillance regions, assembly lines, etc.) working under maximum load regime. Each channel has its own constant numbers of jobs inside at any instant. Each channel has its own specifications, and therefore different kinds of equipment and inventory are needed to serve different channels. There is a limited number of identical maintenance teams (less than the total number of servers in the system). We compute analytically steady- state probabilities of this system, its availability, loss penalty function and other performance characteristics, when both service and maintenance times are exponentially distributed.展开更多
Supercritical CO_(2)(SCO_(2))Brayton cycle has received more and more attention in the field of power generation due to its high cycle efficiency and compact structure.SCO_(2) compressor is the core component of the c...Supercritical CO_(2)(SCO_(2))Brayton cycle has received more and more attention in the field of power generation due to its high cycle efficiency and compact structure.SCO_(2) compressor is the core component of the cycle,and the improvement of its performance is the key to improving the efficiency of the entire cycle.However,the operation of the SCO_(2) compressor near the critical point has brought many design and operation problems.Based on the Reynolds Averaged Navier-Stokes(RANS)model,the performance and flow field of SCO_(2) centrifugal compressors based on different CO_(2) working fluid models are numerically investigated in this paper.The stability and convergence of the compressor steady-state simulation are also discussed.The results show that the fluid based on the Span-Wanger(SW)equation can obtain a more ideal compressor performance curve and capture a more accurate flow field structure,while the CO_(2) ideal gas is not suitable for the calculation of SCO_(2) centrifugal compressors.But its flow field can be used as the initial flow field for numerical calculation of centrifugal compressor based on CO_(2) real gas.展开更多
基于气体等熵喷射过程和绝热变化过程分析氢气泄漏的热力学过程,建立理想气体状态方程、Abel-Noble状态方程和基于NIST(National Institute of Standards and Technology)的真实气体状态方程的计算模型,利用MATLAB对稳态/非稳态泄漏过...基于气体等熵喷射过程和绝热变化过程分析氢气泄漏的热力学过程,建立理想气体状态方程、Abel-Noble状态方程和基于NIST(National Institute of Standards and Technology)的真实气体状态方程的计算模型,利用MATLAB对稳态/非稳态泄漏过程进行计算。结果显示,建立的稳态泄漏模型能够精确计算泄漏口处的相关参数,在保证计算精度的前提下与数值模拟相比,误差可以忽略不计;非稳态泄漏模型中,与基于理想气体状态方程和Abel-Noble状态方程相比,基于NIST的真实气体状态方程误差更小;非稳态泄漏过程中,罐内气体温度高于理论预测值,泄漏质量流量小于理论预测值。真实气体模型在一定程度上体现了热力学模型的局限性,但与数值模拟等计算方法相比,该模型计算更加快捷精准,对实际气体泄漏事故的预测具有理论指导意义。展开更多
Investments in rural land for agriculture, timber, and other natural resource purposes occur frequently and globally. Fundamental principles of liberty and property found in the United States of America’s (“US”) le...Investments in rural land for agriculture, timber, and other natural resource purposes occur frequently and globally. Fundamental principles of liberty and property found in the United States of America’s (“US”) legal system, from its origins to recent US Supreme Court decisions, continue to positively benefit holders of real estate in the Southern US, through a deep-rooted public policy of supporting private property rights and rural economic development. This stable rule of law enhances the long-term adaptability and sustainability of timberland as an asset class. This article is a commentary. It combines legal research methodology with the observations and conclusions of the authors. Its purpose is to demonstrate that the existence of alienable, documentable ownership, and related property rights create inherent stability and security. These principles form the basis of a culture that is defined by the rule of law and is “open for business.” This business mindset is particularly prevalent in the Southern US.展开更多
文摘We propose an experimental scheme for implementing the optimal 1 → 3 real state cloning via linear optical elements. This method relies on one polarized qubit and two location qubits and is feasible with current experimental technology.
基金supported by the Aviation Science Foundation of China
文摘The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliability. Based on the analysis of the characteristics of real-time embedded software, the formal method is introduced into the real-time embedded software testing field and the real-time extended finite state machine （RT-EFSM） model is studied firstly. Then, the time zone division method of real-time embedded system is presented and the definition and description methods of time-constrained transition equivalence class （timeCTEC） are presented. Furthermore, the approaches of the testing sequence and test case generation are put forward. Finally, the proposed method is applied to a typical avionics real- time embedded software testing practice and the examples of the timeCTEC, testing sequences and test cases are given. With the analysis of the testing result, the application verification shows that the proposed method can effectively describe the real-time embedded software state transition characteristics and real-time requirements and play the advantages of the formal methods in accuracy, effectiveness and the automation supporting. Combined with the testing platform, the real-time, closed loop and automated simulation testing for real-time embedded software can be realized effectively.
基金Supported by the National Natural Science F oundation of China(6 98730 35 ) and the Research Fund for the Doctoral Program of Hi
文摘This paper presents a model specifying requirements of real-time systems. Different from existing researches, this model mainly uses rules and templates to represent hierarchical FSMs (Finite State Machine). In this model, one rule corresponds to one state transition of FSM and one template corresponds to one FSM. Rules and information with respect to a FSM can be written in a template. So templates include not only state diagrams, but also information that can not be described by FSM, such as performance requirements. The specification using this model consists of a collection of templates and it is easy for users to understand and to review. After introduced the related researches and principles of the model, this paper specifies requirements of a real-time system with this model, and discusses characters of this model in the end.
文摘In relativistic mechanics the time-like vector characterize the motion in spacetime with speed faster than the speed of light in vacuum c in which the line element ds2=c2dt2-dx2-dx2-dz2 is less than zero (where is infinitesimal change in time, and are infinitesimal change in space), thus the time in relativistic mechanics can instantaneously flow [1], however in quantum mechanics although the time is treated as unobservable parameter (without any Hermitian observable operator have engine-value equivalent to time) any two physical quantity described by two non-commuting observable operatorsand fulfill , the knowledge of one immediately produce the knowledge of the other [2], thus in quantum mechanics if two particles interacted in finite temporal epoch and then separated in space the gaining of knowledge by the local measurement of physical quantity runs on one them (for example the measurement of spin direction of one particle using Stern-Gerlach experiment) immediately produce the knowledge of the complementary physical quantity of the other particle (for example the opposite spin direction of the other particle), this simply called quantum entanglement the concept that so much advanced after publication of the Jon Bell’s 1964 celebrated paper [3] in which he illustrated that we can add parameters to quantum mechanics to determine the results of individual measurements, without changing the statistical predictions, and then he conclude “there must be a mechanism whereby the setting of one measuring device can influence the reading of another instrument, however remote. Moreover, the signal involved must propagate instantaneously so that such a theory could not be Lorentz invariant”. The question now what these signals that can propagate instantaneously? The answer in this paper will be the time signals field which is defined for each constituent matter particle M and at each space point P as the measure of the total length of all occupation and leaving epochs of P by M which is representing a sequence function compactly supported only at the space point occupied by it and indexed by the number of occupation epochs of P by M, thus the flow of this time signal field from the far future to near future through the present to the near past to the far past inferable by the flow of matter particles constituting the system(such as sun, moon earth and clocks hands). Thus the present will represent in this paper a local absolute feature of time signals field defined at each space point as the set of all occupation epochs of it by matter particle, however the past and future will represent relativistic non-local features of the time signal field defined at each space point as a set of all leaving epochs between each two sequential occupation epochs, so the future after one occupation epoch is representing a past of the next one. Thus according to current representation of time, the two Mc-Taggard’s A and B series of time [4] will exist together as temporal set and then the time is real, the A-series in current theory is a set of all occupation and leaving epochs of space point by the matter particle that is consisting of the present, past and future epochs, and the B-series is the set of all leaving epochs of space points between each two sequential occupation epochs which are taking position before or after the discrete occupation epochs between them and then before or after each other.
文摘This paper investigates the positive real control problem for uncertain descriptor systems. The parametric uncertainty is assumed to be norm bounded. Firstly, for the nominal system, a new positive real characterization is given, which is expressed by a strict linear matrix mequality（LMI） without equality constraints. Secondly, for the uncertain system, necessary and sufficient conditions for the solvability of the positive real control problem are derived. Based on these conditions a state feedback law is obtained, which renders the resultant closed-loop system robustly positive real.
文摘In spite of the inherent difficulty, reproducing the exact structure of real flows is a critically important issue in many fields, such as weather forecasting or feedback flow control. In order to obtain information on real flows, extensive studies have been carried out on methodology to integrate measurement and simulation, for example, the four-dimensional variational data assimilation method (4D-Var) or the state estimator such as the Kalman filter or the state observer. Measurement-integrated (MI) simulation is a state observer in which a computational fluid dynamics (CFD) scheme is used as a mathematical model of the physical system instead of a small dimensional linear dynamical system usually used in state observers. A large dimensional nonlinear CFD model makes it possible to accurately reproduce real flows for properly designed feedback signals. This review article surveys the theoretical formulations and applications of MI simulation. Formulations of MI simulation are presented, including governing equations of a flow field observer, those of a linearized error dynamics describing the convergence of the observer, and stabilization of the numerical scheme, which is important in implementation of MI simulation. Applications of MI simulation are presented ranging from fundamental turbulent flows in pipes and Karman vortices in a wind tunnel to clinical application in diagnosis of blood flows in a human body.
文摘We consider a multi server and multichannel real-time system with identical servers (e.g. unmanned aerial vehicles, machine controllers, etc.) that provide services for requests of real-time jobs arriving via several different channels (e.g. surveillance regions, assembly lines, etc.) working under maximum load regime. Each channel has its own constant numbers of jobs inside at any instant. Each channel has its own specifications, and therefore different kinds of equipment and inventory are needed to serve different channels. There is a limited number of identical maintenance teams (less than the total number of servers in the system). We compute analytically steady- state probabilities of this system, its availability, loss penalty function and other performance characteristics, when both service and maintenance times are exponentially distributed.
文摘Supercritical CO_(2)(SCO_(2))Brayton cycle has received more and more attention in the field of power generation due to its high cycle efficiency and compact structure.SCO_(2) compressor is the core component of the cycle,and the improvement of its performance is the key to improving the efficiency of the entire cycle.However,the operation of the SCO_(2) compressor near the critical point has brought many design and operation problems.Based on the Reynolds Averaged Navier-Stokes(RANS)model,the performance and flow field of SCO_(2) centrifugal compressors based on different CO_(2) working fluid models are numerically investigated in this paper.The stability and convergence of the compressor steady-state simulation are also discussed.The results show that the fluid based on the Span-Wanger(SW)equation can obtain a more ideal compressor performance curve and capture a more accurate flow field structure,while the CO_(2) ideal gas is not suitable for the calculation of SCO_(2) centrifugal compressors.But its flow field can be used as the initial flow field for numerical calculation of centrifugal compressor based on CO_(2) real gas.
文摘基于气体等熵喷射过程和绝热变化过程分析氢气泄漏的热力学过程,建立理想气体状态方程、Abel-Noble状态方程和基于NIST(National Institute of Standards and Technology)的真实气体状态方程的计算模型,利用MATLAB对稳态/非稳态泄漏过程进行计算。结果显示,建立的稳态泄漏模型能够精确计算泄漏口处的相关参数,在保证计算精度的前提下与数值模拟相比,误差可以忽略不计;非稳态泄漏模型中,与基于理想气体状态方程和Abel-Noble状态方程相比,基于NIST的真实气体状态方程误差更小;非稳态泄漏过程中,罐内气体温度高于理论预测值,泄漏质量流量小于理论预测值。真实气体模型在一定程度上体现了热力学模型的局限性,但与数值模拟等计算方法相比,该模型计算更加快捷精准,对实际气体泄漏事故的预测具有理论指导意义。
文摘Investments in rural land for agriculture, timber, and other natural resource purposes occur frequently and globally. Fundamental principles of liberty and property found in the United States of America’s (“US”) legal system, from its origins to recent US Supreme Court decisions, continue to positively benefit holders of real estate in the Southern US, through a deep-rooted public policy of supporting private property rights and rural economic development. This stable rule of law enhances the long-term adaptability and sustainability of timberland as an asset class. This article is a commentary. It combines legal research methodology with the observations and conclusions of the authors. Its purpose is to demonstrate that the existence of alienable, documentable ownership, and related property rights create inherent stability and security. These principles form the basis of a culture that is defined by the rule of law and is “open for business.” This business mindset is particularly prevalent in the Southern US.
