A mobile edge cloud provides a platform to accommodate the offloaded traffic workload generated by mobile devices.It can significantly reduce the access delay for mobile application users.However,the high user mobilit...A mobile edge cloud provides a platform to accommodate the offloaded traffic workload generated by mobile devices.It can significantly reduce the access delay for mobile application users.However,the high user mobility brings significant challenges to the service provisioning for mobile users,especially to delay-sensitive mobile applications.With the objective to maximize a profit,which positively associates with the overall admitted traffic served by the local edge cloud,and negatively associates with the access delay as well as virtual machine migration delay,we study a fundamental problem in this paper:how to update the service provisioning solution for a given group of mobile users.Such a profit-maximization problem is formulated as a nonlinear integer linear programming and linearized by absolute value manipulation techniques.Then,we propose a framework of heuristic algorithms to solve this Nondeterministic Polynomial(NP)-hard problem.The numerical simulation results demonstrate the efficiency of the devised algorithms.Some useful summaries are concluded via the analysis of evaluation results.展开更多
Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species...Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species such as terns have the potential to act as visual sentinels of prey availability offshore.However,obtaining diet information from remote bird colonies is often challenging and time consuming.In this pilot study we present a novel approach to combine two established methods to study seabird foraging ecology,providing a powerful and cost-effective tool to study the distribution of prey items available to seabirds.We combined GPS tracking data of Sandwich Terns(Thalasseus sandvicensis)with prey-observations from a hide in 2012 and 2013,and from semicontinuously recorded camera footage in 2017.By doing so,we identified 115 approximate catch locations of prey(86 herring/sprat Clupeidae,29 sandeel Ammodytidae).Combining GPS-data and prey observations yielded detailed knowledge on the movements and chick diets of tracked birds as well as the spatial origin and lengths of captured prey items.Further catch distances of both Clupeidae and Ammodytidae resulted in deliveries of larger prey items and thus higher energy yield per trip,but also a higher energy expenditure per trip.We discuss the limitations and potential of our methodological approach to study foraging energetics during chick-provisioning of seabirds that carry prey items visible in their beaks.展开更多
The emergence of massive ultra-reliable and low latency communications (mURLLC) as a category of age/time/reliability-sensitive service over 6G wireless networks has received considerable research attention, which has...The emergence of massive ultra-reliable and low latency communications (mURLLC) as a category of age/time/reliability-sensitive service over 6G wireless networks has received considerable research attention, which has presented unprecedented challenges. As one of the key enablers for 6G,satellite-terrestrial integrated networks (STIN) have been developed to offer more expansive connectivity and comprehensive 3D coverage in space-aerial-terrestrial domains for supporting 6G mission-critical mURLLC applications while fulfilling diverse and rigorous quality of service (QoS) requirements. In the context of these mURLLC-driven satellite services, data freshness assumes paramount importance, as outdated data may engender unpredictable or catastrophic outcomes.To effectively measure data freshness in satellite-terrestrial integrated communications,age of information(AoI)has recently surfaced as a new dimension of QoS metric to support time-sensitive applications. It is crucial to design new analytical models that ensure stringent and diverse QoS metrics bounded by different key parameters,including AoI,delay,and reliability,over 6G satellite-terrestrial integrated networks. However,due to the complicated and dynamic nature of satellite-terrestrial integrated network environments, the research on efficiently defining new statistical QoS provisioning schemes while taking into account varying degrees of freedom has still been in their infancy. To remedy these deficiencies, in this paper we develop statistical QoS provisioning schemes over 6G satellite-terrestrial integrated networks in the finite blocklength regime. Particularly, we firstly introduce and review key technologies for supporting mURLLC.Secondly,we formulate a number of novel fundamental statistical-QoS metrics in the finite blocklength regime.Finally,we conduct a set of simulations to validate and evaluate our developed statistical QoS provisioning schemes over satellite-terrestrial integrated networks.展开更多
The study of parental food provisioning is essential for understanding the breeding ecology of birds.We conducted the first study using accelerometry to detect food provisioning in birds,using Support Vector Machine(S...The study of parental food provisioning is essential for understanding the breeding ecology of birds.We conducted the first study using accelerometry to detect food provisioning in birds,using Support Vector Machine(SVM)models to identify when adults feed chicks of three different age classes.Accelerometers were attached to the head of adult female Imperial Shags(Leucocarbo atriceps),and various attributes derived from the acceleration signals were used to train SVM models for each chick age class.Model performance improved with chick age class,with SVM models achieving high overall accuracy(>88%)and highest sensitivity in older chick categories(>91%).However,precision values,especially for younger chicks,remained relatively low(between 26%and 45%).The application of a time filter based on the minimum duration of the observed food provisioning behaviours for each chick age category,improved model performance by reducing false provisioning behaviours,particularly in the model for older chicks,which showed the highest precision(72.4%).This study highlights the effectiveness of accelerometry and machine learning in studying parental food provisioning in birds,providing a rapid and accurate data collection method to complement traditional techniques.The described methodology can be applied to any bird species that exhibits distinctive movements while feeding its offspring and has suitable characteristics for attaching an accelerometer to the body part that best captures this movement.Finally,it is hoped that the results of this study will contribute to future research on key questions in parental investment theory and reproductive strategies in birds.展开更多
The scale of global data center market has been explosive in recent years. As the market grows, the demand for fast provisioning of the virtual resources to support elas- tic, manageable, and economical computing over...The scale of global data center market has been explosive in recent years. As the market grows, the demand for fast provisioning of the virtual resources to support elas- tic, manageable, and economical computing over the cloud becomes high. Fast provisioning of large-scale virtual ma- chines （VMs）, in particular, is critical to guarantee quality of service （QoS）. In this paper, we systematically review the existing VM provisioning schemes and classify them in three main categories. We discuss the features and research status of each category, and introduce two recent solutions, VMThunder and VMThunder＋, both of which can provision hundreds of VMs in seconds.展开更多
One of the limitations of current content delivery networks is lack of support for environment aware content delivery. This paper first discusses the requirements of such support, and proposes a new metadata gateway b...One of the limitations of current content delivery networks is lack of support for environment aware content delivery. This paper first discusses the requirements of such support, and proposes a new metadata gateway based environment aware content delivery architecture. The paper discusses in some details key functions and technologies of environment aware content delivery architecture, including its APIs and control policies. Finally the paper presents an application to illustrate advantages of environment aware content delivery architecture in the context of next generation network.展开更多
Scientific workflows have gained the emerging attention in sophisti-cated large-scale scientific problem-solving environments.The pay-per-use model of cloud,its scalability and dynamic deployment enables it suited for ex...Scientific workflows have gained the emerging attention in sophisti-cated large-scale scientific problem-solving environments.The pay-per-use model of cloud,its scalability and dynamic deployment enables it suited for executing scientific workflow applications.Since the cloud is not a utopian environment,failures are inevitable that may result in experiencingfluctuations in the delivered performance.Though a single task failure occurs in workflow based applications,due to its task dependency nature,the reliability of the overall system will be affected drastically.Hence rather than reactive fault-tolerant approaches,proactive measures are vital in scientific workflows.This work puts forth an attempt to con-centrate on the exploration issue of structuring a nature inspired metaheuristics-Intelligent Water Drops Algorithm(IWDA)combined with an efficient machine learning approach-Support Vector Regression(SVR)for task failure prognostica-tion which facilitates proactive fault-tolerance in the scheduling of scientific workflow applications.The failure prediction models in this study have been implemented through SVR-based machine learning approaches and the precision accuracy of prediction is optimized by IWDA and several performance metrics were evaluated on various benchmark workflows.The experimental results prove that the proposed proactive fault-tolerant approach performs better compared with the other existing techniques.展开更多
Altricial birds often display biased preferences in providing parental care for their dependent offspring,especially during food shortages.During this process,such inflexible rules may result in provisioning errors.To...Altricial birds often display biased preferences in providing parental care for their dependent offspring,especially during food shortages.During this process,such inflexible rules may result in provisioning errors.To demonstrate how parents optimize their provisioning strategies,we proposed a“diagnosis model”of parental care to posit that parents will undergo a diagnosis procedure to test whether selecting against some particular offspring based on phenotype is an optimal strategy.We tested this model in an asynchronous hatching bird,the Azure-winged Magpie Cyanopica cyanus,based on 10 years of data about demography and parental provisioning behaviors.Given their higher daily survival rates,core offspring(those hatched on the first day)merits an investment priority compared with their marginal brood mates(those hatched on later days).However,a marginal offspring also merited a priority if it displayed greater weight gain than the expected value at the early post-hatching days.Parents could detect such a marginal offspring via a diagnosis strategy,in which they provisioned the brood at the diagnosis stage by delivering food to every nestling that begged,then biased food toward high-value nestlings at the subsequent decision stage by making a negative response to the begging of low-value nestlings.In this provisioning strategy,the growth performance of a nestling became a more reliable indicator of its investment value than its hatching order or competitive ability.Our findings provide evidence for this“diagnosis model of parental care”wherein parents use a diagnosis method to optimize their provisioning strategy in brood reduction.展开更多
Ecosystem services(ES)are the connection between nature and society,and are essential for the well-being of local communities that depend on them.In Ethiopia,church forests and the surrounding agricultural matrix supp...Ecosystem services(ES)are the connection between nature and society,and are essential for the well-being of local communities that depend on them.In Ethiopia,church forests and the surrounding agricultural matrix supply numerous ES.However,the ES delivered by both land use types have not yet been assessed simultaneously.Here we surveyed both church forests and their agricultural matrices,aiming to quantify,compare and unravel the drivers underlying tree-based ES supply,density and multifunctionality.We found that almost all church forests and half of the agricultural matrices provided high ES densities.ES multifunctionality was higher in the agricultural matrices,suggesting that people deliberately conserve or plant multifunctional tree species.Furthermore,the supply of all categories of ES was positively correlated with church forest age(p-value<0.001)in the agricultural matrix,while the extent of church forest was positively correlated with the density of all categories ecosystem services score in the church forests(p-value<0.001).Our results can be used to prioritize conservation efforts at sites that provide high levels of ES supply,ES density and ES multifunctionality,and to prioritize restoration efforts at sites with low levels thereof.展开更多
Cloud computing is high technology, which fulfills needs of common as well as enterprise level to meet their information and communication technology requirements and so on. Cloud computing extends existing informatio...Cloud computing is high technology, which fulfills needs of common as well as enterprise level to meet their information and communication technology requirements and so on. Cloud computing extends existing information technology capabilities and requirements. Many technologies are being merged with cloud computing, same as that orchestrations can boost cloud service provisioning process. The usage of orchestrations can play vital role to provision cloud services. Cloud service providers can create scalable cloud services at low cost by organizing cloud infrastructure by using cloud orchestrations. Dynamic orchestration flows can generate required cloud computing services to meet service level agreements and quality of services. There is a need to understand issues and barriers involved to integrate cloud orchestrations with cloud service provisioning process. There is also need to understand business related problems bordering cloud computing technology. There is much capacity to do targeted research work for cloud orchestrations and its integration with service level agreements as well as with SLI (service level integration) layer. In this article we have elaborated detailed analysis and identified a number of issues that will affect the cloud service users as well as cloud service providers and cloud service provisioning system. We are defining an approach to orchestrate cloud infrastructure by using orchestration flows, to generate cloud services in order to meet service level agreements and quality of standard.展开更多
In end-to-end QoS provisioning some bandwidth portions on the link may be reserved for certain traffic classes (and for particular set of users) so the congestion problem of concurrent flows (traversing the network si...In end-to-end QoS provisioning some bandwidth portions on the link may be reserved for certain traffic classes (and for particular set of users) so the congestion problem of concurrent flows (traversing the network simultaneously) can appear. It means that in overloaded and poorly connected MPLS/DS networks the CR (Constraint-based Routing) becomes insufficient technique. If traffic engineering is supported with ap-propriate traffic load control the congestion possibility can be predicted before the utilization of guaranteed service. In that sense the initial (proactive) routing can be pre-computed much earlier, possible during SLA (Service Level Agreement) negotiation. In the paper a load simulation technique for load balancing control purpose is proposed. It could be a very good solution for congestion avoidance and for better load-balancing purpose where links are running close to capacity. To be acceptable for real application such complicated load control technique needs very effective algorithm. Proposed algorithm was tested on the network with maximum M core routers on the path and detail results are given for N=3 service classes. Further improve-ment through heuristic approach is made and results are discussed. Some heuristic options show significant complexity savings that is appropriate for load control in huge networks.展开更多
It is foreseen that the Internet of Things (IoT) will comprise billions of connected devices, and this will make the provi?sioning and operation of some IoT connectivity services more challenging. Indeed, IoT services...It is foreseen that the Internet of Things (IoT) will comprise billions of connected devices, and this will make the provi?sioning and operation of some IoT connectivity services more challenging. Indeed, IoT services are very different from lega?cy Internet services because of their dimensioning figures and also because IoT services differ dramatically in terms of na?ture and constraints. For example, IoT services often rely on energy and CPU?constrained sensor technologies, regardless of whether the service is for home automation, smart building, e?health, or power or water metering on a regional or national scale. Also, some IoT services, such as dynamic monitoring of biometric data, manipulation of sensitive information, and pri?vacy needs to be safeguarded whenever this information is for?warded over the underlying IoT network infrastructure. This paper discusses how software?defined networking (SDN) can facilitate the deployment and operation of some advanced IoT services regardless of their nature or scope. SDN introduces a high degree of automation in service delivery and operation-from dynamic IoT service parameter exposure and negotiation to resource allocation, service fulfillment, and assurance. This paper does not argue that all IoT services must adopt SDN. Rather, it is left to the discretion of operators to decide which IoT services can best leverage SDN capabilities. This paper only discusses managed IoT services, i.e., services that are op?erated by a service provider.展开更多
As an important component of cryospheric provisioning services, freshwater provisioning services of the cryosphere is particularly critical to human well-being and socio-economic sustainability. It is imperative to qu...As an important component of cryospheric provisioning services, freshwater provisioning services of the cryosphere is particularly critical to human well-being and socio-economic sustainability. It is imperative to quantitatively estimate the value of freshwater provisioning services to facilitate informed decision-making for ecosystem management and economic development. This study assessed the economic value and associated changes in benefits of freshwater provisioning services for industrial, agricultural, services and domestic water uses combining cost-based method and hydrological model in the Urumqi River during 2010–2016. The results showed that the average annual economic value of agricultural, services, domestic and industrial water uses generated from freshwater provisioning services were estimated to be 1.7, 4.4, 9.9, and 15.7 million CNY. The annual value of snowmelt provisioning services of sectorial water uses was much higher than that of glacier meltwater due to the greater contribution of snowmelt to outlet streamflow than glacier melt. The relative contributions of agricultural, services, domestic and industrial sectors to total economic value of freshwater provisioning services were 6%, 13%, 32%, and 49% respectively, depending on the meltwater supply and market prices. The benefits of freshwater provisioning services from different sectors generally increased in 2010–2016, with a significant increase in the services sector. Considering the impact of changes in freshwater supply under climate change on the assessment of cryospheric provisioning services, the results emphasize the necessity of promoting industrial structure optimization and adopting resource-efficient policies.展开更多
In the era of cloud computing and social networks prosperity, new requirements rise up for cloud services that meet social network’s needs. Several cloud service providers deliver social network services for cloud se...In the era of cloud computing and social networks prosperity, new requirements rise up for cloud services that meet social network’s needs. Several cloud service providers deliver social network services for cloud services users. The aim of this paper is to develop a framework to pick the best cloud service providers from group of available providers based on many Quality-of-Service (“QoS”) criteria attributes in order to enhance efficiency, accuracy and service provisioning. This paper also aims to provide a classification for QoS criteria attributes, which is divided into five main attributes and sub-attributes, helping in enhancing ranking process in the provided framework.展开更多
In this paper, we present an approach to establish efficient and scalable service provisioning in the cloud environment using P2P-based infrastructure for storing, sharing and discovering services. Unlike most other P...In this paper, we present an approach to establish efficient and scalable service provisioning in the cloud environment using P2P-based infrastructure for storing, sharing and discovering services. Unlike most other P2P-based approaches, it allows flexible search queries, since all of them are executed against internal database presenting at each overlay node. Various issues concerning using this approach in the cloud environment, such as load-balancing, queuing, dealing with skewed data and dynamic attributes, are addressed in the paper. The infrastructure proposed in the paper can serve as a base for creating robust, scalable and reliable cloud systems, able to fulfill client’s QoS requirements, and at the same time introduce more efficient utilization of resources to the cloud provider.展开更多
基金partially supported by JSPS KAKENHI under Grant Number JP16J07062
文摘A mobile edge cloud provides a platform to accommodate the offloaded traffic workload generated by mobile devices.It can significantly reduce the access delay for mobile application users.However,the high user mobility brings significant challenges to the service provisioning for mobile users,especially to delay-sensitive mobile applications.With the objective to maximize a profit,which positively associates with the overall admitted traffic served by the local edge cloud,and negatively associates with the access delay as well as virtual machine migration delay,we study a fundamental problem in this paper:how to update the service provisioning solution for a given group of mobile users.Such a profit-maximization problem is formulated as a nonlinear integer linear programming and linearized by absolute value manipulation techniques.Then,we propose a framework of heuristic algorithms to solve this Nondeterministic Polynomial(NP)-hard problem.The numerical simulation results demonstrate the efficiency of the devised algorithms.Some useful summaries are concluded via the analysis of evaluation results.
文摘Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species such as terns have the potential to act as visual sentinels of prey availability offshore.However,obtaining diet information from remote bird colonies is often challenging and time consuming.In this pilot study we present a novel approach to combine two established methods to study seabird foraging ecology,providing a powerful and cost-effective tool to study the distribution of prey items available to seabirds.We combined GPS tracking data of Sandwich Terns(Thalasseus sandvicensis)with prey-observations from a hide in 2012 and 2013,and from semicontinuously recorded camera footage in 2017.By doing so,we identified 115 approximate catch locations of prey(86 herring/sprat Clupeidae,29 sandeel Ammodytidae).Combining GPS-data and prey observations yielded detailed knowledge on the movements and chick diets of tracked birds as well as the spatial origin and lengths of captured prey items.Further catch distances of both Clupeidae and Ammodytidae resulted in deliveries of larger prey items and thus higher energy yield per trip,but also a higher energy expenditure per trip.We discuss the limitations and potential of our methodological approach to study foraging energetics during chick-provisioning of seabirds that carry prey items visible in their beaks.
基金supported by the Key Area Research and Development Program of Guangdong Province under Grant 2020B0101110003in part by the National Natural Science Foundation of China under Grant 62341132+2 种基金the National Key Research and Development Program of China under Grant 2021YFC3002102the Key Research and Development Plan of Shaanxi Province under Grant 2022ZDLGY05-09the Natural Science Basic Research Program of Shaanxi under Grant 2024JC-YBQN-0642.
文摘The emergence of massive ultra-reliable and low latency communications (mURLLC) as a category of age/time/reliability-sensitive service over 6G wireless networks has received considerable research attention, which has presented unprecedented challenges. As one of the key enablers for 6G,satellite-terrestrial integrated networks (STIN) have been developed to offer more expansive connectivity and comprehensive 3D coverage in space-aerial-terrestrial domains for supporting 6G mission-critical mURLLC applications while fulfilling diverse and rigorous quality of service (QoS) requirements. In the context of these mURLLC-driven satellite services, data freshness assumes paramount importance, as outdated data may engender unpredictable or catastrophic outcomes.To effectively measure data freshness in satellite-terrestrial integrated communications,age of information(AoI)has recently surfaced as a new dimension of QoS metric to support time-sensitive applications. It is crucial to design new analytical models that ensure stringent and diverse QoS metrics bounded by different key parameters,including AoI,delay,and reliability,over 6G satellite-terrestrial integrated networks. However,due to the complicated and dynamic nature of satellite-terrestrial integrated network environments, the research on efficiently defining new statistical QoS provisioning schemes while taking into account varying degrees of freedom has still been in their infancy. To remedy these deficiencies, in this paper we develop statistical QoS provisioning schemes over 6G satellite-terrestrial integrated networks in the finite blocklength regime. Particularly, we firstly introduce and review key technologies for supporting mURLLC.Secondly,we formulate a number of novel fundamental statistical-QoS metrics in the finite blocklength regime.Finally,we conduct a set of simulations to validate and evaluate our developed statistical QoS provisioning schemes over satellite-terrestrial integrated networks.
基金supported by a grant from the National Agency for the Promotion of Science and Technology of Argentina(grant PICT,2017-1996 to AGL)by two awards,one from the Association of Field Ornithologists and the other from Aves Argentinas to MDC。
文摘The study of parental food provisioning is essential for understanding the breeding ecology of birds.We conducted the first study using accelerometry to detect food provisioning in birds,using Support Vector Machine(SVM)models to identify when adults feed chicks of three different age classes.Accelerometers were attached to the head of adult female Imperial Shags(Leucocarbo atriceps),and various attributes derived from the acceleration signals were used to train SVM models for each chick age class.Model performance improved with chick age class,with SVM models achieving high overall accuracy(>88%)and highest sensitivity in older chick categories(>91%).However,precision values,especially for younger chicks,remained relatively low(between 26%and 45%).The application of a time filter based on the minimum duration of the observed food provisioning behaviours for each chick age category,improved model performance by reducing false provisioning behaviours,particularly in the model for older chicks,which showed the highest precision(72.4%).This study highlights the effectiveness of accelerometry and machine learning in studying parental food provisioning in birds,providing a rapid and accurate data collection method to complement traditional techniques.The described methodology can be applied to any bird species that exhibits distinctive movements while feeding its offspring and has suitable characteristics for attaching an accelerometer to the body part that best captures this movement.Finally,it is hoped that the results of this study will contribute to future research on key questions in parental investment theory and reproductive strategies in birds.
文摘The scale of global data center market has been explosive in recent years. As the market grows, the demand for fast provisioning of the virtual resources to support elas- tic, manageable, and economical computing over the cloud becomes high. Fast provisioning of large-scale virtual ma- chines （VMs）, in particular, is critical to guarantee quality of service （QoS）. In this paper, we systematically review the existing VM provisioning schemes and classify them in three main categories. We discuss the features and research status of each category, and introduce two recent solutions, VMThunder and VMThunder＋, both of which can provision hundreds of VMs in seconds.
文摘One of the limitations of current content delivery networks is lack of support for environment aware content delivery. This paper first discusses the requirements of such support, and proposes a new metadata gateway based environment aware content delivery architecture. The paper discusses in some details key functions and technologies of environment aware content delivery architecture, including its APIs and control policies. Finally the paper presents an application to illustrate advantages of environment aware content delivery architecture in the context of next generation network.
文摘Scientific workflows have gained the emerging attention in sophisti-cated large-scale scientific problem-solving environments.The pay-per-use model of cloud,its scalability and dynamic deployment enables it suited for executing scientific workflow applications.Since the cloud is not a utopian environment,failures are inevitable that may result in experiencingfluctuations in the delivered performance.Though a single task failure occurs in workflow based applications,due to its task dependency nature,the reliability of the overall system will be affected drastically.Hence rather than reactive fault-tolerant approaches,proactive measures are vital in scientific workflows.This work puts forth an attempt to con-centrate on the exploration issue of structuring a nature inspired metaheuristics-Intelligent Water Drops Algorithm(IWDA)combined with an efficient machine learning approach-Support Vector Regression(SVR)for task failure prognostica-tion which facilitates proactive fault-tolerance in the scheduling of scientific workflow applications.The failure prediction models in this study have been implemented through SVR-based machine learning approaches and the precision accuracy of prediction is optimized by IWDA and several performance metrics were evaluated on various benchmark workflows.The experimental results prove that the proposed proactive fault-tolerant approach performs better compared with the other existing techniques.
基金This work was supported by the National Natural Science Foundation of China(grants 31370417,31572271,31772465,32071491).
文摘Altricial birds often display biased preferences in providing parental care for their dependent offspring,especially during food shortages.During this process,such inflexible rules may result in provisioning errors.To demonstrate how parents optimize their provisioning strategies,we proposed a“diagnosis model”of parental care to posit that parents will undergo a diagnosis procedure to test whether selecting against some particular offspring based on phenotype is an optimal strategy.We tested this model in an asynchronous hatching bird,the Azure-winged Magpie Cyanopica cyanus,based on 10 years of data about demography and parental provisioning behaviors.Given their higher daily survival rates,core offspring(those hatched on the first day)merits an investment priority compared with their marginal brood mates(those hatched on later days).However,a marginal offspring also merited a priority if it displayed greater weight gain than the expected value at the early post-hatching days.Parents could detect such a marginal offspring via a diagnosis strategy,in which they provisioned the brood at the diagnosis stage by delivering food to every nestling that begged,then biased food toward high-value nestlings at the subsequent decision stage by making a negative response to the begging of low-value nestlings.In this provisioning strategy,the growth performance of a nestling became a more reliable indicator of its investment value than its hatching order or competitive ability.Our findings provide evidence for this“diagnosis model of parental care”wherein parents use a diagnosis method to optimize their provisioning strategy in brood reduction.
基金flnancial support from VLIR-UOS,Belgium through the VLIR-IUC Interuniversity cooperation with Bahir Dar University,Ethiopia (BDU-IUC)
文摘Ecosystem services(ES)are the connection between nature and society,and are essential for the well-being of local communities that depend on them.In Ethiopia,church forests and the surrounding agricultural matrix supply numerous ES.However,the ES delivered by both land use types have not yet been assessed simultaneously.Here we surveyed both church forests and their agricultural matrices,aiming to quantify,compare and unravel the drivers underlying tree-based ES supply,density and multifunctionality.We found that almost all church forests and half of the agricultural matrices provided high ES densities.ES multifunctionality was higher in the agricultural matrices,suggesting that people deliberately conserve or plant multifunctional tree species.Furthermore,the supply of all categories of ES was positively correlated with church forest age(p-value<0.001)in the agricultural matrix,while the extent of church forest was positively correlated with the density of all categories ecosystem services score in the church forests(p-value<0.001).Our results can be used to prioritize conservation efforts at sites that provide high levels of ES supply,ES density and ES multifunctionality,and to prioritize restoration efforts at sites with low levels thereof.
文摘Cloud computing is high technology, which fulfills needs of common as well as enterprise level to meet their information and communication technology requirements and so on. Cloud computing extends existing information technology capabilities and requirements. Many technologies are being merged with cloud computing, same as that orchestrations can boost cloud service provisioning process. The usage of orchestrations can play vital role to provision cloud services. Cloud service providers can create scalable cloud services at low cost by organizing cloud infrastructure by using cloud orchestrations. Dynamic orchestration flows can generate required cloud computing services to meet service level agreements and quality of services. There is a need to understand issues and barriers involved to integrate cloud orchestrations with cloud service provisioning process. There is also need to understand business related problems bordering cloud computing technology. There is much capacity to do targeted research work for cloud orchestrations and its integration with service level agreements as well as with SLI (service level integration) layer. In this article we have elaborated detailed analysis and identified a number of issues that will affect the cloud service users as well as cloud service providers and cloud service provisioning system. We are defining an approach to orchestrate cloud infrastructure by using orchestration flows, to generate cloud services in order to meet service level agreements and quality of standard.
文摘In end-to-end QoS provisioning some bandwidth portions on the link may be reserved for certain traffic classes (and for particular set of users) so the congestion problem of concurrent flows (traversing the network simultaneously) can appear. It means that in overloaded and poorly connected MPLS/DS networks the CR (Constraint-based Routing) becomes insufficient technique. If traffic engineering is supported with ap-propriate traffic load control the congestion possibility can be predicted before the utilization of guaranteed service. In that sense the initial (proactive) routing can be pre-computed much earlier, possible during SLA (Service Level Agreement) negotiation. In the paper a load simulation technique for load balancing control purpose is proposed. It could be a very good solution for congestion avoidance and for better load-balancing purpose where links are running close to capacity. To be acceptable for real application such complicated load control technique needs very effective algorithm. Proposed algorithm was tested on the network with maximum M core routers on the path and detail results are given for N=3 service classes. Further improve-ment through heuristic approach is made and results are discussed. Some heuristic options show significant complexity savings that is appropriate for load control in huge networks.
文摘It is foreseen that the Internet of Things (IoT) will comprise billions of connected devices, and this will make the provi?sioning and operation of some IoT connectivity services more challenging. Indeed, IoT services are very different from lega?cy Internet services because of their dimensioning figures and also because IoT services differ dramatically in terms of na?ture and constraints. For example, IoT services often rely on energy and CPU?constrained sensor technologies, regardless of whether the service is for home automation, smart building, e?health, or power or water metering on a regional or national scale. Also, some IoT services, such as dynamic monitoring of biometric data, manipulation of sensitive information, and pri?vacy needs to be safeguarded whenever this information is for?warded over the underlying IoT network infrastructure. This paper discusses how software?defined networking (SDN) can facilitate the deployment and operation of some advanced IoT services regardless of their nature or scope. SDN introduces a high degree of automation in service delivery and operation-from dynamic IoT service parameter exposure and negotiation to resource allocation, service fulfillment, and assurance. This paper does not argue that all IoT services must adopt SDN. Rather, it is left to the discretion of operators to decide which IoT services can best leverage SDN capabilities. This paper only discusses managed IoT services, i.e., services that are op?erated by a service provider.
基金This work was financially supported by the National Natural Science Foundation of China(41690141)the National Key Research and Development Program of China(2019YFC1510500).
文摘As an important component of cryospheric provisioning services, freshwater provisioning services of the cryosphere is particularly critical to human well-being and socio-economic sustainability. It is imperative to quantitatively estimate the value of freshwater provisioning services to facilitate informed decision-making for ecosystem management and economic development. This study assessed the economic value and associated changes in benefits of freshwater provisioning services for industrial, agricultural, services and domestic water uses combining cost-based method and hydrological model in the Urumqi River during 2010–2016. The results showed that the average annual economic value of agricultural, services, domestic and industrial water uses generated from freshwater provisioning services were estimated to be 1.7, 4.4, 9.9, and 15.7 million CNY. The annual value of snowmelt provisioning services of sectorial water uses was much higher than that of glacier meltwater due to the greater contribution of snowmelt to outlet streamflow than glacier melt. The relative contributions of agricultural, services, domestic and industrial sectors to total economic value of freshwater provisioning services were 6%, 13%, 32%, and 49% respectively, depending on the meltwater supply and market prices. The benefits of freshwater provisioning services from different sectors generally increased in 2010–2016, with a significant increase in the services sector. Considering the impact of changes in freshwater supply under climate change on the assessment of cryospheric provisioning services, the results emphasize the necessity of promoting industrial structure optimization and adopting resource-efficient policies.
文摘In the era of cloud computing and social networks prosperity, new requirements rise up for cloud services that meet social network’s needs. Several cloud service providers deliver social network services for cloud services users. The aim of this paper is to develop a framework to pick the best cloud service providers from group of available providers based on many Quality-of-Service (“QoS”) criteria attributes in order to enhance efficiency, accuracy and service provisioning. This paper also aims to provide a classification for QoS criteria attributes, which is divided into five main attributes and sub-attributes, helping in enhancing ranking process in the provided framework.
文摘In this paper, we present an approach to establish efficient and scalable service provisioning in the cloud environment using P2P-based infrastructure for storing, sharing and discovering services. Unlike most other P2P-based approaches, it allows flexible search queries, since all of them are executed against internal database presenting at each overlay node. Various issues concerning using this approach in the cloud environment, such as load-balancing, queuing, dealing with skewed data and dynamic attributes, are addressed in the paper. The infrastructure proposed in the paper can serve as a base for creating robust, scalable and reliable cloud systems, able to fulfill client’s QoS requirements, and at the same time introduce more efficient utilization of resources to the cloud provider.
