The practical engineering of satellite tracking telemetry and command(TT&C)is often disturbed by unpredictable external factors,including the temporary rise in a significant quantity of satellite TT&C tasks,te...The practical engineering of satellite tracking telemetry and command(TT&C)is often disturbed by unpredictable external factors,including the temporary rise in a significant quantity of satellite TT&C tasks,temporary failures and failures of some TT&C resources,and so on.To improve the adaptability and robustness of satellite TT&C systems when faced with uncertain dynamic disturbances,a hierarchical disturbance propagation mechanism and an improved contract network dynamic scheduling method for satellite TT&C resources were designed to address the dynamic scheduling problem of satellite TT&C resources.Firstly,the characteristics of the dynamic scheduling problem of satellite TT&C resources are analyzed,and a mathematical model is established with the weighted optimization objectives of maximizing the revenue from task completion and minimizing the degree of plan disturbance.Then,a bottom-up distributed dynamic collaborative scheduling framework for satellite TT&C resources is proposed,which includes a task layer,a resource layer,a central internal collaboration layer,and a central external collaboration layer.Dynamic disturbances are propagated layer by layer from the task layer to the central external collaboration layer in a bottom-up manner,using efficient heuristic strategies in the task layer and the resource layer,respectively.We use improved contract network algorithms in the center internal collaboration layer and the center external collaboration layer,the original scheduling plan is quickly adjusted to minimize the impact of disturbances while effectively completing dynamic task requirements.Finally,a large number of simulation experiments were carried out and compared with various comparative algorithms.The results show that the proposed algorithm can effectively improve the solution effect of satellite TT&C resource dynamic scheduling problems,and has good application prospects.展开更多
During the course of knowledge economic, setting up e nterprise dynamic alliances is gradually becoming the most effective way for the enterprises, which seek fast development. There are many researches about enter pr...During the course of knowledge economic, setting up e nterprise dynamic alliances is gradually becoming the most effective way for the enterprises, which seek fast development. There are many researches about enter prise dynamic alliances in other fields, but there is few research about leg al relationship among members of enterprise dynamic alliances and ownership of i ntellectual property achievements which are brought by dynamic alliances. Th is paper discusses legal relationship among members of dynamic alliances and own ership of intellectual property achievements under various legal relationshi ps from the point of view of law.展开更多
Spatiotemporal dynamics of the damped dc-driven Frenkel-Kontorova lattice is studied. Multistable topologies are shown. Intermittency of the dynamical contraction factor is found, and this behavior is a consequence of...Spatiotemporal dynamics of the damped dc-driven Frenkel-Kontorova lattice is studied. Multistable topologies are shown. Intermittency of the dynamical contraction factor is found, and this behavior is a consequence of the collisions of kinks and antikinks. Fast kinks and antikinks are unstable. The transition from the localized kink to the whirling mode is found to be a temporal bifurcation cascade of generations of kink-antikink pairs and the collision-induced avalanche dynamics. Noise-induced topology transition is observed and discussed.展开更多
Traditional approach of design by contract, due to mixing the contract code with application code, is difficult for the extensibility and reusability of software system. This paper presents a framework named JADBC for...Traditional approach of design by contract, due to mixing the contract code with application code, is difficult for the extensibility and reusability of software system. This paper presents a framework named JADBC for design by contract based on Aspect-Oriented Programming （AOP） to resolve these problems. By providing a new modularized element, aspect, the framework successfully separates the contracts in design by contract, from functional codes. The implementation of this framework is based on dynamic AOP which can have the contract changed at rtmtime, consequently, enhancing program flexibility. JADBC framework modularizes the contracts in a clear-cut fashion that is easier to design, implement, and maintain.展开更多
Contraction behavior of a liquid-solid fluidized bed has been investigated numerically. Based on a simple hydrodynamic model proposed by Brandani and Zhang （2006）, a case study for solid particles with a density of ...Contraction behavior of a liquid-solid fluidized bed has been investigated numerically. Based on a simple hydrodynamic model proposed by Brandani and Zhang （2006）, a case study for solid particles with a density of 3,000 kg/m^3 and a diameter of 2.5× 10^-3 m is simulated in a two-dimensional fluidized bed （0.50 m height and 0.10 m width）. Due to the continuity of numerical computation, there is a transition region between two zones of different solid holdups when the liquid velocity is suddenly changed. The top, middle and bottom interfaces are explored to obtain a reasonable interface height. The simulated results show that the steady time of the middle interface is more close to Gibilaro＇s theory and suitable for describing the contraction process of a phase interface. Furthermore, the effect of liquid velocity and particle diameter is simulated in the other two-dimensional fluidized bed （0.10 m height and 0.02 m width） where the solid particles are glass beads whose properties are similar to those of the catalyst particles used in the alkylation process. The results also show good agreement with Gibilaro＇s theory, and that larger particles lead to a more obvious bed contraction.展开更多
This paper considers a dynamical system defined by a set of ordinary autonomous differential equations with discontinuous right-hand side. Such systems typically appear in economic modelling where there are two or mor...This paper considers a dynamical system defined by a set of ordinary autonomous differential equations with discontinuous right-hand side. Such systems typically appear in economic modelling where there are two or more regimes with a switching between them. Switching between regimes may be a consequence of market forces or deliberately forced in form of policy implementation. Stiefenhofer and Giesl [1] introduce such a model. The purpose of this paper is to show that a metric function defined between two adjacent trajectories contracts in forward time leading to exponentially asymptotically stability of (non)smooth periodic orbits. Hence, we define a local contraction function and distribute it over the smooth and nonsmooth parts of the periodic orbits. The paper shows exponentially asymptotical stability of a periodic orbit using a contraction property of the distance function between two adjacent nonsmooth trajectories over the entire periodic orbit. Moreover it is shown that the ω-limit set of the (non)smooth periodic orbit for two adjacent initial conditions is the same.展开更多
Our paper presents a project that involves two research questions: does the choice of a related problem by the tutorial system allow the problem solving process which is blocked for the student to be restarted? What i...Our paper presents a project that involves two research questions: does the choice of a related problem by the tutorial system allow the problem solving process which is blocked for the student to be restarted? What information about learning do related problems returned by the system provide us? We answer the first question according to the didactic engineering, whose mode of validation is internal and based on the confrontation between an a priori analysis and an a posteriori analysis that relies on data from experiments in schools. We consider the student as a subject whose adaptation processes are conditioned by the problem and the possible interactions with the computer environment, and also by his knowledge, usually implicit, of the institutional norms that condition his relationship with geometry. Choosing a set of good problems within the system is therefore an essential element of the learning model. Since the source of a problem depends on the student’s actions with the computer tool, it is necessary to wait and see what are the related to problems that are returned to him before being able to identify patterns and assess the learning. With the simultaneity of collecting and analysing interactions in each class, we answer the second question according to a grounded theory analysis. By approaching the problems posed by the system and the designs in play at learning blockages, our analysis links the characteristics of problems to the design components in order to theorize on the decisional, epistemological, representational, didactic and instrumental aspects of the subject-milieu system in interaction.展开更多
The realty(real estate)management of ownership of buildings includes the owner(homeowner)entrust-management and the owner self-management,the former through the way of realty service contracts,the latter through the r...The realty(real estate)management of ownership of buildings includes the owner(homeowner)entrust-management and the owner self-management,the former through the way of realty service contracts,the latter through the resolution of the owners’assembly and the owners’committee.The legal disputes of realty service contracts involve balancing interests among the realty service enterprise,individual owner,and all the owners.We should use dynamic balancing of the interests of the three parties to implement the interests of the win-win cooperation rather than the interests of the trade-off of“all or nothing.”The realty service contract is similar to the entrustment contract,both of which are based on the owners’entrustment.The duty to provide realty service is not simply equivalent to fiduciary duty.The realty service contract has the essence of both behavior debt and result debt.For the former,the general provisions of the entrustment contract can be referred to,and for the latter,the general provisions of the contract for work can be referred to.In view of the group characteristics of the realty service contract,owners have no right to terminate the realty service contract at any time but should obey the principle of due process and take the majority mechanism to make a dismissal resolution resolution.The resolutions and management stipulations worked out by the owners’assembly in a majority mechanism,both of which belong to resolution behavior and are legal tools of the owners’autonomy,shall be binding on all the owners.The relationship between the owner,the owner’s assembly,and the owner’s committee is similar to the fiduciary relationship.If the decision made by the owners’assembly or the owners’committee and the management stipulation infringes upon the legal rights and interests of the owners,the injured owner has the right to revocation litigation.At present,residential commodity owners have a relatively low degree of autonomy in China,and legal disputes over realty services are frequent.In the future,we need to perfect the legal incentive and constraint measures,and stimulate the vitality of owner autonomy to promote better implementation of the owner self-management and owner entrust-management.展开更多
Objective:To observe the HRV changes before and after the radiofrequency current catheter ablationventricular premature beats originated from different site of right ventricular outflow tract.Methods:A total of 102 pa...Objective:To observe the HRV changes before and after the radiofrequency current catheter ablationventricular premature beats originated from different site of right ventricular outflow tract.Methods:A total of 102 patients with frequent RVOT-VPC admitted to our hospital were accepted radiofrequency current catheter ablation (RF). According to the origin of RVOT-VPC, it was divided into 2 groups, one is from ventricular septum, and the other one is from free wall, and in each group, male and female are observed separately.Results:(1) HRV before RF ablation: 1) rMSSD in the female patients with RVOT-VPC from free wall was significantly lower than those from septum;2) frequency domain index (W, LF) were higher than normal range, and in male patients, LF/HF<1 were found, but in female patients, LF/HF>1. (2) HRV after RF ablation: 1) Significant changes were found in female patients with RVOT-VPC from septum, rMSSD, PNN50, HF and LF decreased;2) In female patients with RVOT-VPC from free wall, rMSSD decreased;3) In male patients, there were no significant HRV changes found before and after RF ablation. (3) Heart rate changes: 1) In female patients with RVOT-VPC from septum, heart rate decreased significantly ((76.47±9.47) bpm vs (69.29±14.59) bpm)2) No significant changes were found in male patients.Conclusion:In patients with RVOT-PVC sympathetic and vagus excitability increased, and after catheter ablation, in female patients with RVOT-PVC originated from septum, the HRV index relating to sympathetic and vagus excitability significantly decreased.展开更多
基金This work was supported in part by the National Natural Science Foundation of China(No.62373380).
文摘The practical engineering of satellite tracking telemetry and command(TT&C)is often disturbed by unpredictable external factors,including the temporary rise in a significant quantity of satellite TT&C tasks,temporary failures and failures of some TT&C resources,and so on.To improve the adaptability and robustness of satellite TT&C systems when faced with uncertain dynamic disturbances,a hierarchical disturbance propagation mechanism and an improved contract network dynamic scheduling method for satellite TT&C resources were designed to address the dynamic scheduling problem of satellite TT&C resources.Firstly,the characteristics of the dynamic scheduling problem of satellite TT&C resources are analyzed,and a mathematical model is established with the weighted optimization objectives of maximizing the revenue from task completion and minimizing the degree of plan disturbance.Then,a bottom-up distributed dynamic collaborative scheduling framework for satellite TT&C resources is proposed,which includes a task layer,a resource layer,a central internal collaboration layer,and a central external collaboration layer.Dynamic disturbances are propagated layer by layer from the task layer to the central external collaboration layer in a bottom-up manner,using efficient heuristic strategies in the task layer and the resource layer,respectively.We use improved contract network algorithms in the center internal collaboration layer and the center external collaboration layer,the original scheduling plan is quickly adjusted to minimize the impact of disturbances while effectively completing dynamic task requirements.Finally,a large number of simulation experiments were carried out and compared with various comparative algorithms.The results show that the proposed algorithm can effectively improve the solution effect of satellite TT&C resource dynamic scheduling problems,and has good application prospects.
基金Project (No .70 1 71 0 0 7)supportedbyNationalScienceFoundationofChina
文摘During the course of knowledge economic, setting up e nterprise dynamic alliances is gradually becoming the most effective way for the enterprises, which seek fast development. There are many researches about enter prise dynamic alliances in other fields, but there is few research about leg al relationship among members of enterprise dynamic alliances and ownership of i ntellectual property achievements which are brought by dynamic alliances. Th is paper discusses legal relationship among members of dynamic alliances and own ership of intellectual property achievements under various legal relationshi ps from the point of view of law.
文摘Spatiotemporal dynamics of the damped dc-driven Frenkel-Kontorova lattice is studied. Multistable topologies are shown. Intermittency of the dynamical contraction factor is found, and this behavior is a consequence of the collisions of kinks and antikinks. Fast kinks and antikinks are unstable. The transition from the localized kink to the whirling mode is found to be a temporal bifurcation cascade of generations of kink-antikink pairs and the collision-induced avalanche dynamics. Noise-induced topology transition is observed and discussed.
基金the National Natural Science Foundation of China (60773006)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060486045)
文摘Traditional approach of design by contract, due to mixing the contract code with application code, is difficult for the extensibility and reusability of software system. This paper presents a framework named JADBC for design by contract based on Aspect-Oriented Programming （AOP） to resolve these problems. By providing a new modularized element, aspect, the framework successfully separates the contracts in design by contract, from functional codes. The implementation of this framework is based on dynamic AOP which can have the contract changed at rtmtime, consequently, enhancing program flexibility. JADBC framework modularizes the contracts in a clear-cut fashion that is easier to design, implement, and maintain.
基金Financial support from the National Natural Science Foundation of China(20976191 and 51025624)Program for New Century Excellent Talents in University (NCET-09-0342)111 Project (B12034)
文摘Contraction behavior of a liquid-solid fluidized bed has been investigated numerically. Based on a simple hydrodynamic model proposed by Brandani and Zhang （2006）, a case study for solid particles with a density of 3,000 kg/m^3 and a diameter of 2.5× 10^-3 m is simulated in a two-dimensional fluidized bed （0.50 m height and 0.10 m width）. Due to the continuity of numerical computation, there is a transition region between two zones of different solid holdups when the liquid velocity is suddenly changed. The top, middle and bottom interfaces are explored to obtain a reasonable interface height. The simulated results show that the steady time of the middle interface is more close to Gibilaro＇s theory and suitable for describing the contraction process of a phase interface. Furthermore, the effect of liquid velocity and particle diameter is simulated in the other two-dimensional fluidized bed （0.10 m height and 0.02 m width） where the solid particles are glass beads whose properties are similar to those of the catalyst particles used in the alkylation process. The results also show good agreement with Gibilaro＇s theory, and that larger particles lead to a more obvious bed contraction.
文摘This paper considers a dynamical system defined by a set of ordinary autonomous differential equations with discontinuous right-hand side. Such systems typically appear in economic modelling where there are two or more regimes with a switching between them. Switching between regimes may be a consequence of market forces or deliberately forced in form of policy implementation. Stiefenhofer and Giesl [1] introduce such a model. The purpose of this paper is to show that a metric function defined between two adjacent trajectories contracts in forward time leading to exponentially asymptotically stability of (non)smooth periodic orbits. Hence, we define a local contraction function and distribute it over the smooth and nonsmooth parts of the periodic orbits. The paper shows exponentially asymptotical stability of a periodic orbit using a contraction property of the distance function between two adjacent nonsmooth trajectories over the entire periodic orbit. Moreover it is shown that the ω-limit set of the (non)smooth periodic orbit for two adjacent initial conditions is the same.
文摘Our paper presents a project that involves two research questions: does the choice of a related problem by the tutorial system allow the problem solving process which is blocked for the student to be restarted? What information about learning do related problems returned by the system provide us? We answer the first question according to the didactic engineering, whose mode of validation is internal and based on the confrontation between an a priori analysis and an a posteriori analysis that relies on data from experiments in schools. We consider the student as a subject whose adaptation processes are conditioned by the problem and the possible interactions with the computer environment, and also by his knowledge, usually implicit, of the institutional norms that condition his relationship with geometry. Choosing a set of good problems within the system is therefore an essential element of the learning model. Since the source of a problem depends on the student’s actions with the computer tool, it is necessary to wait and see what are the related to problems that are returned to him before being able to identify patterns and assess the learning. With the simultaneity of collecting and analysing interactions in each class, we answer the second question according to a grounded theory analysis. By approaching the problems posed by the system and the designs in play at learning blockages, our analysis links the characteristics of problems to the design components in order to theorize on the decisional, epistemological, representational, didactic and instrumental aspects of the subject-milieu system in interaction.
文摘The realty(real estate)management of ownership of buildings includes the owner(homeowner)entrust-management and the owner self-management,the former through the way of realty service contracts,the latter through the resolution of the owners’assembly and the owners’committee.The legal disputes of realty service contracts involve balancing interests among the realty service enterprise,individual owner,and all the owners.We should use dynamic balancing of the interests of the three parties to implement the interests of the win-win cooperation rather than the interests of the trade-off of“all or nothing.”The realty service contract is similar to the entrustment contract,both of which are based on the owners’entrustment.The duty to provide realty service is not simply equivalent to fiduciary duty.The realty service contract has the essence of both behavior debt and result debt.For the former,the general provisions of the entrustment contract can be referred to,and for the latter,the general provisions of the contract for work can be referred to.In view of the group characteristics of the realty service contract,owners have no right to terminate the realty service contract at any time but should obey the principle of due process and take the majority mechanism to make a dismissal resolution resolution.The resolutions and management stipulations worked out by the owners’assembly in a majority mechanism,both of which belong to resolution behavior and are legal tools of the owners’autonomy,shall be binding on all the owners.The relationship between the owner,the owner’s assembly,and the owner’s committee is similar to the fiduciary relationship.If the decision made by the owners’assembly or the owners’committee and the management stipulation infringes upon the legal rights and interests of the owners,the injured owner has the right to revocation litigation.At present,residential commodity owners have a relatively low degree of autonomy in China,and legal disputes over realty services are frequent.In the future,we need to perfect the legal incentive and constraint measures,and stimulate the vitality of owner autonomy to promote better implementation of the owner self-management and owner entrust-management.
基金Natural Science Foundation Project of Beijing(7122173).
文摘Objective:To observe the HRV changes before and after the radiofrequency current catheter ablationventricular premature beats originated from different site of right ventricular outflow tract.Methods:A total of 102 patients with frequent RVOT-VPC admitted to our hospital were accepted radiofrequency current catheter ablation (RF). According to the origin of RVOT-VPC, it was divided into 2 groups, one is from ventricular septum, and the other one is from free wall, and in each group, male and female are observed separately.Results:(1) HRV before RF ablation: 1) rMSSD in the female patients with RVOT-VPC from free wall was significantly lower than those from septum;2) frequency domain index (W, LF) were higher than normal range, and in male patients, LF/HF<1 were found, but in female patients, LF/HF>1. (2) HRV after RF ablation: 1) Significant changes were found in female patients with RVOT-VPC from septum, rMSSD, PNN50, HF and LF decreased;2) In female patients with RVOT-VPC from free wall, rMSSD decreased;3) In male patients, there were no significant HRV changes found before and after RF ablation. (3) Heart rate changes: 1) In female patients with RVOT-VPC from septum, heart rate decreased significantly ((76.47±9.47) bpm vs (69.29±14.59) bpm)2) No significant changes were found in male patients.Conclusion:In patients with RVOT-PVC sympathetic and vagus excitability increased, and after catheter ablation, in female patients with RVOT-PVC originated from septum, the HRV index relating to sympathetic and vagus excitability significantly decreased.
