This paper describes an experimental work in order to assess the efficiency of slit dam on non-viscous debris flow. Some results have been acquired as follows： （1） there are three kinds of blocking type; Total-bloc...This paper describes an experimental work in order to assess the efficiency of slit dam on non-viscous debris flow. Some results have been acquired as follows： （1） there are three kinds of blocking type; Total-blocking, opening and part-blocking. The blocking conditions of slit dam are closely link to b/dmax （the ratio of slit width to maximum diameter of solid matter）, as b/dmax is less than 0. 739, the slit dam is total- blocking; and b/dmax is more than 1. 478, the slit dam will be opening; whereas b/dma ranges from 0. 739 to 1. 478, the slit dam is part-blocking. （2） Variation of the mean density passing through slit dam is the most obvious as b/dmax ranges from 0. 739 to 1. 232. （2） According to experimental results, slit dams have been shown to be effective in reducing debris flow density while slit density ∑ b/B （B is slit dam width） ranges from 0.2 to 0. 5.展开更多
Aim To Put forward an improve algorithm for real-time connection admission control (CAC) decision. Methods converted equations of Cell loss ratio (CLR) upper bound were derived based on typical approaches to reduce co...Aim To Put forward an improve algorithm for real-time connection admission control (CAC) decision. Methods converted equations of Cell loss ratio (CLR) upper bound were derived based on typical approaches to reduce computing load. Moreover, the effects of usage parameter control (UPC) policing and bandwidth allocation functions were combined to deduce improver equations. computing load and admission region of the new algorithm were analyzed, while numerical examples and comparisons with classical non-parametic method were also included. Results Computing burden was reduced. More accurate estimation of CLR was obtained. The admission region of new algorithm was larger than typical non-parametric approach and was variable according to the burst length.Conclusion The calculation burden of new algorithm for CLR estimation is lighter than classical non-parametric approach. In addition to that, just as many information as what we can get in connection setup process are used for CAC decision. So it is not only a practicable but also an effective method that can be used in real-time processing.展开更多
Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement pro...Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement process of rock blocks in rock avalanche, due to the high velocity and impacts against obstructions. In view of the energy consumption theory for brittle rock fragmentation proposed by Bond, which relates energy to size reduction, a theoretical model is proposed to estimate the average fragment size for a moving rock block when it impacts against an obstruction. Then, different forms of motion are studied, with various drop heights and slope angles for the moving rock block. The calculated results reveal that the average fragment size decreases as the drop height increases, whether for free-fall or for a sliding or rolling rock block, and the decline in size is rapid for low heights and slow for increasing heights in the corresponding curves. Moreover, the average fragment size also decreases as the slope angle increases for a slidingrock block. In addition, a rolling rock block has a higher degree of fragmentation than a sliding rock block, even for the same slope angle and block volume. Finally, to compare with others' results, the approximate number of fragments is estimated for each calculated example, and the results show that the proposed model is applicable to a relatively isotropic moving rock block.展开更多
A new Distributed Dynamic Channel Allocation (DDCA) algorithm named Combined DDCA is proposed in this paper.In this algorithm, each base station selects channels by learning through past experience of channel usag...A new Distributed Dynamic Channel Allocation (DDCA) algorithm named Combined DDCA is proposed in this paper.In this algorithm, each base station selects channels by learning through past experience of channel usage together with CIR measurement. Computer simulations are used to evaluate system performances. Performances are evaluated in two criteria, blocking probability and interaction probability. Comparisons with other DDCA algorithms have been carried out to validate the proposed algorithm.展开更多
文摘This paper describes an experimental work in order to assess the efficiency of slit dam on non-viscous debris flow. Some results have been acquired as follows： （1） there are three kinds of blocking type; Total-blocking, opening and part-blocking. The blocking conditions of slit dam are closely link to b/dmax （the ratio of slit width to maximum diameter of solid matter）, as b/dmax is less than 0. 739, the slit dam is total- blocking; and b/dmax is more than 1. 478, the slit dam will be opening; whereas b/dma ranges from 0. 739 to 1. 478, the slit dam is part-blocking. （2） Variation of the mean density passing through slit dam is the most obvious as b/dmax ranges from 0. 739 to 1. 232. （2） According to experimental results, slit dams have been shown to be effective in reducing debris flow density while slit density ∑ b/B （B is slit dam width） ranges from 0.2 to 0. 5.
文摘Aim To Put forward an improve algorithm for real-time connection admission control (CAC) decision. Methods converted equations of Cell loss ratio (CLR) upper bound were derived based on typical approaches to reduce computing load. Moreover, the effects of usage parameter control (UPC) policing and bandwidth allocation functions were combined to deduce improver equations. computing load and admission region of the new algorithm were analyzed, while numerical examples and comparisons with classical non-parametic method were also included. Results Computing burden was reduced. More accurate estimation of CLR was obtained. The admission region of new algorithm was larger than typical non-parametric approach and was variable according to the burst length.Conclusion The calculation burden of new algorithm for CLR estimation is lighter than classical non-parametric approach. In addition to that, just as many information as what we can get in connection setup process are used for CAC decision. So it is not only a practicable but also an effective method that can be used in real-time processing.
基金supported by the National Natural Science Foundation of China (41472272, 41225011)the Youth Science and Technology Fund of Sichuan Province (2016JQ0011)the Opening Fund of the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology) (SKLGP2013K015)
文摘Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement process of rock blocks in rock avalanche, due to the high velocity and impacts against obstructions. In view of the energy consumption theory for brittle rock fragmentation proposed by Bond, which relates energy to size reduction, a theoretical model is proposed to estimate the average fragment size for a moving rock block when it impacts against an obstruction. Then, different forms of motion are studied, with various drop heights and slope angles for the moving rock block. The calculated results reveal that the average fragment size decreases as the drop height increases, whether for free-fall or for a sliding or rolling rock block, and the decline in size is rapid for low heights and slow for increasing heights in the corresponding curves. Moreover, the average fragment size also decreases as the slope angle increases for a slidingrock block. In addition, a rolling rock block has a higher degree of fragmentation than a sliding rock block, even for the same slope angle and block volume. Finally, to compare with others' results, the approximate number of fragments is estimated for each calculated example, and the results show that the proposed model is applicable to a relatively isotropic moving rock block.
文摘A new Distributed Dynamic Channel Allocation (DDCA) algorithm named Combined DDCA is proposed in this paper.In this algorithm, each base station selects channels by learning through past experience of channel usage together with CIR measurement. Computer simulations are used to evaluate system performances. Performances are evaluated in two criteria, blocking probability and interaction probability. Comparisons with other DDCA algorithms have been carried out to validate the proposed algorithm.
