In ubiquitous stub environment, it is a critical challenge to design an optimal device aggregation mechanism to meet all requested ubiquitous services simultaneously with resource- limited devices and bandwidth-limite...In ubiquitous stub environment, it is a critical challenge to design an optimal device aggregation mechanism to meet all requested ubiquitous services simultaneously with resource- limited devices and bandwidth-limited network. Firstly, Multi-Service oriented Devices Aggregation Problem is generalized and formulated based on QoS-metric with Multi-attribute Decision Making. Secondly, a Multi-Service oriented Devices Aggregation Mechanism is proposed to deal the problem in which there are two processes： Dimensionless Processing and Device Aggregation Approach. At last, the simulation is implemented with OPNET and MATLAB. We integrate different QoS factors, such as Average Utility, Utility distribution, Total Utility distribution and Service Failure Rate, to reflect user experience.展开更多
Umbrella-shaped assembly of cylindrical fins is optimized by adopting analytical method and taking dimensionless mean thermal resistance (MTR) as performance index. The optimal construct of umbrella-shaped assembly is...Umbrella-shaped assembly of cylindrical fins is optimized by adopting analytical method and taking dimensionless mean thermal resistance (MTR) as performance index. The optimal construct of umbrella-shaped assembly is obtained. The results show that the heat conductance performance of the assembly becomes ever worse with ever greater number of elemental cylindrical fins,the umbrella-shaped assembly reduces to cylindrical fin in some values of design parameters,and the diameters’ dependence on design parameters is weak for the optimized assembly. An equivalent thermal resistance defined based on entransy dissipation rate (EDR) reflects an average heat transfer effect of the assembly. The constructal design corresponding to the minimum EDR (or MTR) should be adopted for designing an assembly of fins in engineering at the limit safe condition.展开更多
Recently, a new dark energy model called AHDE was proposed. In this model, dark energy consists of two parts： cosmological constant A and holographic dark energy （HDE）. Two key parameters of this model are the frac...Recently, a new dark energy model called AHDE was proposed. In this model, dark energy consists of two parts： cosmological constant A and holographic dark energy （HDE）. Two key parameters of this model are the fractional density of cosmological constant Ω2A0, and the dimensionless HDE parameter c. Since these two parameters determine the dynamical properties of DE and the destiny of universe, it is important to study the impacts of different values of ΩA0 and c on the AHDE model. In this paper, we apply various DE diagnostic tools to diagnose AHDE models with different values of ΩA0 and c; these tools include statefinder hierarchy {S3^（1） ,S4（1）fractional growth parameter E, and composite null diagnostic （CND）, which is a combination of{S3（1）,S4（1）} and E. We find that： （1） adopting different values of ΩA0 only has quantitative impacts on the evolution of the AHDE model, while adopting different c has qualitative impacts; （2） compared with S（1）, S（41） can give larger differences among the cosmic evolutions of the AHDE model associated with different ΩA0 or different c; （3） compared with the case of using a single diagnostic, adopting a CND pair has much stronger ability to diagnose the AHDE model.展开更多
文摘In ubiquitous stub environment, it is a critical challenge to design an optimal device aggregation mechanism to meet all requested ubiquitous services simultaneously with resource- limited devices and bandwidth-limited network. Firstly, Multi-Service oriented Devices Aggregation Problem is generalized and formulated based on QoS-metric with Multi-attribute Decision Making. Secondly, a Multi-Service oriented Devices Aggregation Mechanism is proposed to deal the problem in which there are two processes： Dimensionless Processing and Device Aggregation Approach. At last, the simulation is implemented with OPNET and MATLAB. We integrate different QoS factors, such as Average Utility, Utility distribution, Total Utility distribution and Service Failure Rate, to reflect user experience.
基金supported by the National Natural Science Foundation of China (Grant No.10905093)the Program for New Century Excellent Talents in University of China (Grant No.NCET-04-1006)the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No.200136)
文摘Umbrella-shaped assembly of cylindrical fins is optimized by adopting analytical method and taking dimensionless mean thermal resistance (MTR) as performance index. The optimal construct of umbrella-shaped assembly is obtained. The results show that the heat conductance performance of the assembly becomes ever worse with ever greater number of elemental cylindrical fins,the umbrella-shaped assembly reduces to cylindrical fin in some values of design parameters,and the diameters’ dependence on design parameters is weak for the optimized assembly. An equivalent thermal resistance defined based on entransy dissipation rate (EDR) reflects an average heat transfer effect of the assembly. The constructal design corresponding to the minimum EDR (or MTR) should be adopted for designing an assembly of fins in engineering at the limit safe condition.
基金supported by the National Natural Science Foundation of China(Grant No.11405024)
文摘Recently, a new dark energy model called AHDE was proposed. In this model, dark energy consists of two parts： cosmological constant A and holographic dark energy （HDE）. Two key parameters of this model are the fractional density of cosmological constant Ω2A0, and the dimensionless HDE parameter c. Since these two parameters determine the dynamical properties of DE and the destiny of universe, it is important to study the impacts of different values of ΩA0 and c on the AHDE model. In this paper, we apply various DE diagnostic tools to diagnose AHDE models with different values of ΩA0 and c; these tools include statefinder hierarchy {S3^（1） ,S4（1）fractional growth parameter E, and composite null diagnostic （CND）, which is a combination of{S3（1）,S4（1）} and E. We find that： （1） adopting different values of ΩA0 only has quantitative impacts on the evolution of the AHDE model, while adopting different c has qualitative impacts; （2） compared with S（1）, S（41） can give larger differences among the cosmic evolutions of the AHDE model associated with different ΩA0 or different c; （3） compared with the case of using a single diagnostic, adopting a CND pair has much stronger ability to diagnose the AHDE model.
