In this paper we propose a consistent and asymptotically normal estimator (CAN) of intensities ρ1 , ρ2 for a queueing network with feedback (in which a job may return to previously visited nodes) with distribution-f...In this paper we propose a consistent and asymptotically normal estimator (CAN) of intensities ρ1 , ρ2 for a queueing network with feedback (in which a job may return to previously visited nodes) with distribution-free inter-arrival and service times. Using this estimator and its estimated variance, some 100(1-α)% asymptotic confidence intervals of intensities are constructed. Also bootstrap approaches such as Standard bootstrap, Bayesian bootstrap, Percentile bootstrap and Bias-corrected and accelerated bootstrap are also applied to develop the confidence intervals of intensities. A comparative analysis is conducted to demonstrate performances of the confidence intervals of intensities for a queueing network with short run data.展开更多
Wild pistachio tree （Pistacia mutica） is considered the most important species in the Zagros forests. It can adapt to unfavorable environmental conditions. To find the suitable ecological conditions for pistachio sp...Wild pistachio tree （Pistacia mutica） is considered the most important species in the Zagros forests. It can adapt to unfavorable environmental conditions. To find the suitable ecological conditions for pistachio species, we investigated different environmental factors such as gradient, aspect and position of the slopes through the distribution area. Frequency of pistachio trees in the north and northwest of Qalajeh forests was 36.4% and 1%, respectively. Maximum （32%） and minimum （13%） number of wild pistachio trees were in 30%--60% and 〉120% slope classes, respectively. The most number and least number of pistachio trees were found at elevations of 1100-1200 m and 2200-2300 m, respectively. The percentage of pistachio canopy coverage was 10. The average percentage of herbaceous coverage was 6.5. Pistachio trees of diameter per hectare at breast height （DBH） 〉20 cm numbered 5 while average number of pistachio trees was 8 per hectare. Pistachio seedlings per hectare averaged 3.5. The number of other species per ha was 7 trees. The effect of aspect on other species was not significant （p=0.151）. Slope class and geographical aspect did not affect regeneration （p=0.275 and p=0.111, respectively）. Pistachio plays an important economic role in semi-arid areas, therefore it is essential to protect and restore Qalajeh forests through participation by government and local people.展开更多
Keeping Vehicular Ad hoc Network （VANET） from attacks requires secure and efficient distribution of information about bad entitles. Negative messages are pieces of information that define the negative attributes of ...Keeping Vehicular Ad hoc Network （VANET） from attacks requires secure and efficient distribution of information about bad entitles. Negative messages are pieces of information that define the negative attributes of vehicles. By formally defining the negative message, we observe that accuracy is essential for its efficient distribution. We formally define the coverage percentage and accurate coverage percentage to describe the availability and distribution efficiency of negative message. These two metrics can jointly evaluate the performance of a distribution method. To obtain both high coverage percentage and high accurate coverage percentage, we propose meet-cloud, a scheme based on meet-table and cloud computing to securely and accurately distribute negative messages in VANET. A meet-table in a Road Side Unit （RSU） records the vehicles it encounters. All meet- tables are sent to cloud service to aggregate a global meet-table. The algorithm for distributing and redistributing negative messages are designed. Security analysis shows that meet-cloud is secure against fake and holding on to negative message attacks. Simulations and analysis demonstrate that meet-cloud is secure under denial of service and fake meet-table attacks. The simulation results also justify that meet-cloud outperforms the RSU broadcast and epidemic model.展开更多
文摘In this paper we propose a consistent and asymptotically normal estimator (CAN) of intensities ρ1 , ρ2 for a queueing network with feedback (in which a job may return to previously visited nodes) with distribution-free inter-arrival and service times. Using this estimator and its estimated variance, some 100(1-α)% asymptotic confidence intervals of intensities are constructed. Also bootstrap approaches such as Standard bootstrap, Bayesian bootstrap, Percentile bootstrap and Bias-corrected and accelerated bootstrap are also applied to develop the confidence intervals of intensities. A comparative analysis is conducted to demonstrate performances of the confidence intervals of intensities for a queueing network with short run data.
文摘Wild pistachio tree （Pistacia mutica） is considered the most important species in the Zagros forests. It can adapt to unfavorable environmental conditions. To find the suitable ecological conditions for pistachio species, we investigated different environmental factors such as gradient, aspect and position of the slopes through the distribution area. Frequency of pistachio trees in the north and northwest of Qalajeh forests was 36.4% and 1%, respectively. Maximum （32%） and minimum （13%） number of wild pistachio trees were in 30%--60% and 〉120% slope classes, respectively. The most number and least number of pistachio trees were found at elevations of 1100-1200 m and 2200-2300 m, respectively. The percentage of pistachio canopy coverage was 10. The average percentage of herbaceous coverage was 6.5. Pistachio trees of diameter per hectare at breast height （DBH） 〉20 cm numbered 5 while average number of pistachio trees was 8 per hectare. Pistachio seedlings per hectare averaged 3.5. The number of other species per ha was 7 trees. The effect of aspect on other species was not significant （p=0.151）. Slope class and geographical aspect did not affect regeneration （p=0.275 and p=0.111, respectively）. Pistachio plays an important economic role in semi-arid areas, therefore it is essential to protect and restore Qalajeh forests through participation by government and local people.
基金supported by the National Natural Science Foundation of China (No. 61262072)
文摘Keeping Vehicular Ad hoc Network （VANET） from attacks requires secure and efficient distribution of information about bad entitles. Negative messages are pieces of information that define the negative attributes of vehicles. By formally defining the negative message, we observe that accuracy is essential for its efficient distribution. We formally define the coverage percentage and accurate coverage percentage to describe the availability and distribution efficiency of negative message. These two metrics can jointly evaluate the performance of a distribution method. To obtain both high coverage percentage and high accurate coverage percentage, we propose meet-cloud, a scheme based on meet-table and cloud computing to securely and accurately distribute negative messages in VANET. A meet-table in a Road Side Unit （RSU） records the vehicles it encounters. All meet- tables are sent to cloud service to aggregate a global meet-table. The algorithm for distributing and redistributing negative messages are designed. Security analysis shows that meet-cloud is secure against fake and holding on to negative message attacks. Simulations and analysis demonstrate that meet-cloud is secure under denial of service and fake meet-table attacks. The simulation results also justify that meet-cloud outperforms the RSU broadcast and epidemic model.
