5 research outputs found
Energy Efficient Resource Allocation for Virtual Network Services with Dynamic Workload in Cloud Data Centers
Title from PDF of title page, viewed on March 21, 2016Dissertation advisor: Baek-Young ChoiVitaIncludes bibliographical references (pages 126-143)Thesis (Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2016With the rapid proliferation of cloud computing, more and more network services and
applications are deployed on cloud data centers. Their energy consumption and green
house gas emissions have significantly increased. Some efforts have been made to control
and lower energy consumption of data centers such as, proportional energy consuming
hardware, dynamic provisioning, and virtualization machine techniques. However, it is
still common that many servers and network resources are often underutilized, and idle
servers spend a large portion of their peak power consumption.
Network virtualization and resource sharing have been employed to improve energy
efficiency of data centers by aggregating workload to a few physical nodes and switch
the idle nodes to sleep mode. Especially, with the advent of live migration, a virtual node
can be moved from one physical node to another physical node without service disrup
tion. It is possible to save more energy by shrinking virtual nodes to a small set of physical
nodes and turning the idle nodes to sleep mode when the service workload is low, and expanding
virtual nodes to a large set of physical nodes to satisfy QoS requirements when
the service workload is high. When the service provider explicates the desired virtual
network including a specific topology, and a set of virtual nodes with certain resource
demands, the infrastructure provider computes how the given virtual network is embedded to its operated data centers with minimum energy consumption. When the service
provider only gives some description about the network service and the desired QoS requirements, the infrastructure provider has more freedom on how to allocate resources for
the network service.
For the first problem, we consider the evolving workload of the virtual networks
or virtual applications and residual resources in data centers, and build a novel model of
energy efficient virtual network embedding (EE-VNE) in order to minimize energy usage
in the physical network consists of multiple data centers. In this model, both operation
cost for executing network services’ task and migration cost for the live migrations of
virtual nodes are counted toward the total energy consumption. In addition, rather than
random generated physical network topology, we use practical assumption about physical
network topology in our model.
Due to the NP-hardness of the proposed model, we develop a heuristic algorithm for virtual network scheduling and mapping. In doing so, we specifically take the expected
energy consumption at different times, virtual network operation and future migration
costs, and a data center architecture into consideration. Our extensive evaluation results
showthatouralgorithmcouldreduceenergyconsumptionupto40%andtakeuptoa57%
higher number of virtual network requests over other existing virtual mapping schemes.
However, through comparison with CPLEX based exact algorithm, we identify
that there is still a gap between the heuristic solution and the optimal solution. Therefore,
after investigation other solutions, we convert the origin EE-VNE problem to an Ant
Colony Optimization (ACO) problem by building the construction model and presenting
the transition probability formula. Then, ACO based algorithm has been adapted to solve
the ACO-EE-VNE problem. In addition, we reduce the space complexity of ACO-EE
VNE by developing a novel way to track and update the pheromone.
For the second problem, we design a framework to dynamically allocate resources
for a network service by employing container based virtual nodes. In the framework,each
network service would have a pallet container and a set of execution containers. The pal
let container requests resource based on certain strategy, creates execution containers with
assigned resources and manage the life cycle of the containers; while the execution containers execute the assigned job for the network service. Formulations are presented to
optimize resource usage efficiency and save energy consumption for network services
with dynamic workload, and a heuristic algorithm is proposed to solve the optimization
problem. Our numerical results show that container based resource allocation provide
more flexible and saves more cost than virtual service deployment with fixed virtual machines and demands.
In addition, we study the content distribution problem with joint optimization goal
and varied size of contents in cloud storage. Previous research on content distribution
mainly focuses on reducing latency experienced by content customers. A few recent studies address the issue of bandwidth usage in CDNs, as the bandwidth consumption is
an important issue due to its relevance to the cost of content providers. However, few
researches consider both bandwidth consumption and delay performance for the content
providers that use cloud storages with limited budgets, which is the focus of this study. We
develop an efficient light-weight approximation algorithm toward the joint optimization
problem of content placement. We also conduct the analysis of its theoretical complexities. The performance bound of the proposed approximation algorithm exhibits a much
better worst case than those in previous studies. We further extend the approximate algorithm into a distributed version that allows it to promptly react to dynamic changes in
users’ interests. The extensive results from both simulations and Planetlab experiments
exhibit that the performance is near optimal for most of the practical conditions.Introduction -- Related work -- Energy efficient virtual network embedding for green data centers using data center topology and future migration -- Ant colony optimization based energy efficient virtual network embedding -- Energy aware container based resource allocation for virtual services in green data centers -- Achieving optimal content delivery using cloud storage -- Conclusions and future wor
Proceedings of the Workshop on Identification and Control of Flexible Space Structures, volume 1
Identification and control of flexible space structures were studied. Exploration of the most advanced modeling estimation, identification and control methodologies to flexible space structures was discussed. The following general areas were discussed: space platforms, antennas, and flight experiments; control/structure interactions - modeling, integrated design and optimization, control and stabilization, and shape control; control technology; control of space stations; large antenna control, dynamics and control experiments, and control/structure interaction experiments