In the age of online workload explosion,cloud users are increasing exponentialy.Therefore,large scale data centers are required in cloud environment that leads to high energy consumption.Hence,optimal resource utiliza...In the age of online workload explosion,cloud users are increasing exponentialy.Therefore,large scale data centers are required in cloud environment that leads to high energy consumption.Hence,optimal resource utilization is essential to improve energy efficiency of cloud data center.Although,most of the existing literature focuses on virtual machine(VM)consolidation for increasing energy efficiency at the cost of service level agreement degradation.In order to improve the existing approaches,load aware three-gear THReshold(LATHR)as well as modified best fit decreasing(MBFD)algorithm is proposed for minimizing total energy consumption while improving the quality of service in terms of SLA.It offers promising results under dynamic workload and variable number of VMs(1-290)allocated on individual host.The outcomes of the proposed work are measured in terms of SLA,energy consumption,instruction energy ratio(IER)and the number of migrations against the varied numbers of VMs.From experimental results it has been concluded that the proposed technique reduced the SLA violations(55%,26%and 39%)and energy consumption(17%,12%and 6%)as compared to median absolute deviation(MAD),inter quartile range(IQR)and double threshold(THR)overload detection policies,respectively.展开更多
We compare the optimal operating cost of the two bicriterion policies, <p,T> and <p,N>, for an M/G/1 queueing system with second optional service, in which the length of the vacation period is randomly con...We compare the optimal operating cost of the two bicriterion policies, <p,T> and <p,N>, for an M/G/1 queueing system with second optional service, in which the length of the vacation period is randomly controlled either by the number of arrivals during the idle period or by a timer. After all the customers are served in the queue exhaustively, the server immediately takes a vacation and may operate <p,T> policy or <p,N> policy. For the two bicriterion policies, the total average cost function per unit time is developed to search the optimal stationary operating policies at a minimum cost. Based upon the optimal cost the explicit forms for joint optimum threshold values of (p,T) and (p,N) are obtained.展开更多
With the intensive research into global coupling relationships,ecological carrying capacity（ECC）,seen as the crucial link between natural ecosystems and human systems,has gradually become an important tool for inter...With the intensive research into global coupling relationships,ecological carrying capacity（ECC）,seen as the crucial link between natural ecosystems and human systems,has gradually become an important tool for interdisciplinary research in ecology,resources science and environmental science,as well as for research on regional sustainable development.However,ECC research remains immature and lacks a complete theoretical system,as a result of many limiting factors and different space-time conditions.At present,Chinese and foreign studies focus on methods to evaluate ECC while neglecting to identify the internal driving mechanisms of ECC.In this article,based on the development and conceptualization of ECC,we introduce three evaluation methods for ECC：ecological footprint（EF）,human appropriation of net primary production（HANPP）and ecosystem services consumption（ESC）.Furthermore,we illuminate research focuses and developmental directions for ECC with respect to driving mechanisms,threshold,comprehensive evaluation systems and coupling dynamic model of multi ecological factors,in order to provide a reference for future ECC research.展开更多
文摘In the age of online workload explosion,cloud users are increasing exponentialy.Therefore,large scale data centers are required in cloud environment that leads to high energy consumption.Hence,optimal resource utilization is essential to improve energy efficiency of cloud data center.Although,most of the existing literature focuses on virtual machine(VM)consolidation for increasing energy efficiency at the cost of service level agreement degradation.In order to improve the existing approaches,load aware three-gear THReshold(LATHR)as well as modified best fit decreasing(MBFD)algorithm is proposed for minimizing total energy consumption while improving the quality of service in terms of SLA.It offers promising results under dynamic workload and variable number of VMs(1-290)allocated on individual host.The outcomes of the proposed work are measured in terms of SLA,energy consumption,instruction energy ratio(IER)and the number of migrations against the varied numbers of VMs.From experimental results it has been concluded that the proposed technique reduced the SLA violations(55%,26%and 39%)and energy consumption(17%,12%and 6%)as compared to median absolute deviation(MAD),inter quartile range(IQR)and double threshold(THR)overload detection policies,respectively.
文摘We compare the optimal operating cost of the two bicriterion policies, <p,T> and <p,N>, for an M/G/1 queueing system with second optional service, in which the length of the vacation period is randomly controlled either by the number of arrivals during the idle period or by a timer. After all the customers are served in the queue exhaustively, the server immediately takes a vacation and may operate <p,T> policy or <p,N> policy. For the two bicriterion policies, the total average cost function per unit time is developed to search the optimal stationary operating policies at a minimum cost. Based upon the optimal cost the explicit forms for joint optimum threshold values of (p,T) and (p,N) are obtained.
基金The National Key Research and Development Program of China(2016YFC0503500)National Science and Technology Major Project(Z2016C01G01)
文摘With the intensive research into global coupling relationships,ecological carrying capacity（ECC）,seen as the crucial link between natural ecosystems and human systems,has gradually become an important tool for interdisciplinary research in ecology,resources science and environmental science,as well as for research on regional sustainable development.However,ECC research remains immature and lacks a complete theoretical system,as a result of many limiting factors and different space-time conditions.At present,Chinese and foreign studies focus on methods to evaluate ECC while neglecting to identify the internal driving mechanisms of ECC.In this article,based on the development and conceptualization of ECC,we introduce three evaluation methods for ECC：ecological footprint（EF）,human appropriation of net primary production（HANPP）and ecosystem services consumption（ESC）.Furthermore,we illuminate research focuses and developmental directions for ECC with respect to driving mechanisms,threshold,comprehensive evaluation systems and coupling dynamic model of multi ecological factors,in order to provide a reference for future ECC research.
