4,121 research outputs found
Memetic Multi-Objective Particle Swarm Optimization-Based Energy-Aware Virtual Network Embedding
In cloud infrastructure, accommodating multiple virtual networks on a single
physical network reduces power consumed by physical resources and minimizes
cost of operating cloud data centers. However, mapping multiple virtual network
resources to physical network components, called virtual network embedding
(VNE), is known to be NP-hard. With considering energy efficiency, the problem
becomes more complicated. In this paper, we model energy-aware virtual network
embedding, devise metrics for evaluating performance of energy aware virtual
network-embedding algorithms, and propose an energy aware virtual
network-embedding algorithm based on multi-objective particle swarm
optimization augmented with local search to speed up convergence of the
proposed algorithm and improve solutions quality. Performance of the proposed
algorithm is evaluated and compared with existing algorithms using extensive
simulations, which show that the proposed algorithm improves virtual network
embedding by increasing revenue and decreasing energy consumption.Comment: arXiv admin note: text overlap with arXiv:1504.0684
Binary PSOGSA for Load Balancing Task Scheduling in Cloud Environment
In cloud environments, load balancing task scheduling is an important issue
that directly affects resource utilization. Unquestionably, load balancing
scheduling is a serious aspect that must be considered in the cloud research
field due to the significant impact on both the back end and front end.
Whenever an effective load balance has been achieved in the cloud, then good
resource utilization will also be achieved. An effective load balance means
distributing the submitted workload over cloud VMs in a balanced way, leading
to high resource utilization and high user satisfaction. In this paper, we
propose a load balancing algorithm, Binary Load Balancing-Hybrid Particle Swarm
Optimization and Gravitational Search Algorithm (Bin-LB-PSOGSA), which is a
bio-inspired load balancing scheduling algorithm that efficiently enables the
scheduling process to improve load balance level on VMs. The proposed algorithm
finds the best Task-to-Virtual machine mapping that is influenced by the length
of submitted workload and VM processing speed. Results show that the proposed
Bin-LB-PSOGSA achieves better VM load average than the pure Bin-LB-PSO and
other benchmark algorithms in terms of load balance level
Energy-Aware Virtual Network Embedding Approach for Distributed Cloud
Network virtualization has caught the attention of many researchers in recent
years. It facilitates the process of creating several virtual networks over a
single physical network. Despite this advantage, however, network
virtualization suffers from the problem of mapping virtual links and nodes to
physical network in most efficient way. This problem is called virtual network
embedding ("VNE"). Many researches have been proposed in an attempt to solve
this problem, which have many optimization aspects, such as improving embedding
strategies in a way that preserves energy, reducing embedding cost and
increasing embedding revenue. Moreover, some researchers have extended their
algorithms to be more compatible with the distributed clouds instead of a
single infrastructure provider ("ISP"). This paper proposes energy aware
particle swarm optimization algorithm for distributed clouds. This algorithm
aims to partition each virtual network request ("VNR") to subgraphs, using the
Heavy Clique Matching technique ("HCM") to generate a coarsened graph. Each
coarsened node in the coarsened graph is assigned to a suitable data center
("DC"). Inside each DC, a modified particle swarm optimization algorithm is
initiated to find the near optimal solution for the VNE problem. The proposed
algorithm was tested and evaluated against existing algorithms using extensive
simulations, which shows that the proposed algorithm outperforms other
algorithms.Comment: International Journal of Advanced Computer Science and
Applications(IJACSA
PRP and BMAC for Musculoskeletal Conditions via Biomaterial Carriers.
Platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) are orthobiologic therapies considered as an alternative to the current therapies for muscle, bone and cartilage. Different formulations of biomaterials have been used as carriers for PRP and BMAC in order to increase regenerative processes. The most common biomaterials utilized in conjunction with PRP and BMAC clinical trials are organic scaffolds and natural or synthetic polymers. This review will cover the combinatorial strategies of biomaterial carriers with PRP and BMAC for musculoskeletal conditions (MsCs) repair and regeneration in clinical trials. The main objective is to review the therapeutic use of PRP and BMAC as a treatment option for muscle, bone and cartilage injuries
Multi-objective evolution of artificial neural networks in multi-class medical diagnosis problems with class imbalance
This paper proposes a novel multi-objective optimisation approach to solving both the problem of finding good structural and parametric choices in an ANN and the problem of training a classifier with a heavily skewed data set. The state-of-the-art CMA-PAES-HAGA multi-objective evolutionary algorithm [41] is used to simultaneously optimise the structure, weights, and biases of a population of ANNs with respect to not only the overall classification accuracy, but the classification accuracies of each individual target class. The effectiveness of this approach is then demonstrated on a real-world multi-class problem in medical diagnosis (classification of fetal cardiotocograms) where more than 75% of the data belongs to the majority class and the rest to two other minority classes. The optimised ANN is shown to significantly outperform a standard feed-forward ANN with respect to minority class recognition at the cost of slightly worse performance in terms of overall classification accuracy
AdS/CFT correspondence via R-current correlation functions revisited
Motivated by realizing open/closed string duality in the work by Gopakumar
[Phys. Rev. D70:025009,2004], we study two and three-point correlation
functions of R-current vector fields in N=4 super Yang-Mills theory. These
correlation functions in free field limit can be derived from the worldline
formalism and written as heat kernel integrals in the position space. We show
that reparametrizing these integrals converts them to the expected AdS
supergravity results which are known in terms of bulk to boundary propagator.
We expect that this reparametrization corresponds to transforming open string
moduli parameterization to the closed string ones.Comment: 23 pages, v2: calculations clarified, references added, v3: sections
re-arranged with more explanations, 4 figures and an appendix adde
CMA-PAES: Pareto archived evolution strategy using covariance matrix adaptation for multi-objective optimisation
The quality of Evolutionary Multi-Objective Optimisation (EMO) approximation sets can be measured by their proximity, diversity and pertinence. In this paper we introduce a modular and extensible Multi-Objective Evolutionary Algorithm (MOEA) capable of converging to the Pareto-optimal front in a minimal number of function evaluations and producing a diverse approximation set. This algorithm, called the Covariance Matrix Adaptation Pareto Archived Evolution Strategy (CMA-PAES), is a form of (μ + λ) Evolution Strategy which uses an online archive of previously found Pareto-optimal solutions (maintained by a bounded Pareto-archiving scheme) as well as a population of solutions which are subjected to variation using Covariance Matrix Adaptation. The performance of CMA-PAES is compared to NSGA-II (currently considered the benchmark MOEA in the literature) on the ZDT test suite of bi-objective optimisation problems and the significance of the results are analysed using randomisation testing. © 2012 IEEE
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