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Server cluster systems are widely used to realize high performance and fault-tolerant information systems. In order to make a server cluster fault-tolerant, multiple replicas of each application process are performed on multiple servers. However, the larger electric energy is consumed in a server cluster due to redundant execution of multiple replicas. The redundant power consumption laxity-based...
Online Social Networks (OSN) have attracted a lot of end-users in the last few years. The success of Facebook, Twitter, Snapchat leads to a huge increase of data transiting in the network of telecom operators. To face to this increase, network operators have to find solutions. The Named Data Networking (NDN) paradigm, focusing on interest-based requests for content, is a good possible networking solution,...
Datacenters, or warehouse scale computers, are rapidly increasing in size and power consumption. However, this growth comes at the cost of an increasing thermal load that must be removed to prevent overheating and server failure. In this paper, we propose to use phase changing materials (PCM) to shape the thermal load of a datacenter, absorbing and releasing heat when it is advantageous to do so....
Latency-critical workloads (e.g., web search), common in datacenters, require stable tail (e.g., 95th percentile) latencies of a few milliseconds. Servers running these workloads are kept lightly loaded to meet these stringent latency targets. This low utilization wastes billions of dollars in energy and equipment annually. Applying dynamic power management to latency-critical workloads is challenging...
Over the past years organizations have been moving their enterprise applications to the cloud to take advantage of cloud's utility computing and elasticity. However, in enterprise applications or workflows, generally, different components/tasks will have different scaling requirements and finding an ideal deployment configuration and having the application to scale up and down based on the incoming...
Wireless cellular networks are undergoing severe changes due to the ever increasing demand of data rate. Additionally, the demand is more and more heterogeneous (imbalanced) in time and space. Sudden peaks in demand at a certain location have to be absorbed by the network. While operators traditionally over-provisioned their own separate network capacity in order to reduce the blocking and overload...
As Applications are moved from physical servers to virtual machines sharing storage resources, they experience large variation in I/O latencies. While maintaining average performance in such virtualized environments is important to conform to service level agreements (SLA), cloud users also expect their applications to have minimum variation in tail end latencies like 90th percentile latency for predictable...
The IP multimedia subsystem provides a platform for group communication services using Session Initiation Protocol (SIP). SIP supports the services where participation of multiple users is involved. The centralized conferencing framework limits the ability to have large number of participants because of the overhead on the server. In this paper, an efficient solution for enhancing the capability of...
An Edge-Overlay model constructing virtual networks using both virtual switches and IP tunnels is promising in cloud datacenter networks. But software-implemented virtual switches can cause performance problems because the packet processing load is concentrated on a particular CPU core. Although multi queue functions like Receive Side Scaling (RSS) can distribute the load onto multiple CPU cores,...
Compared to the traditional online creation and work display platform, "Creative Studio Online" (CSO), based on the cloud model and Web-based Graphics Library (WebGL) technique, is more practical and more powerful. CSO provides an online creation and work display framework for the people who are engaged in cultural and creative industry. The key merit of this framework is to offer users...
Companies nowadays are widely adopting cloud computing. One important problem encountered to efficiently adopt public IaaS clouds is wasting leased computational resources, which remain active if no policy is established to implement elasticity according to the demand. As a consequence, the cloud use becomes more expensive than expected, leading to higher costs that may turn the company business unattractive...
Cloud computing has recently received considerable attention, as a promising approach for delivering ICT services by improving the utilisation of data centre resources. On the other hand, the increased usage of ICT, jointly with the increased cost of energy, make designing and managing data centres with energy efficient strategies a crucial and strategical problem. In the literature there are many...
This paper presents a scalable model-driven approach to quantify the availability of resources and optimal distribution of tasks over these resources, such that the average response time of tasks is minimized. To reduce the complexity of analysis and solution time, we use an integrated stochastic based approach. To achieve this, first we use clustering algorithm to group the tasks into distinct classes...
Energy efficiency of cloud data centers is of great concern today and has been tackled by many researchers. Dynamic VM placement is a well-known strategy to improve energy efficiency of a data center. Virtual machines (VMs) under light load are consolidated into a small number of physical machines (PMs) to turn idle PMs into low-power states. Although live migration is essential for dynamic VM placement,...
Fat-tree is a popular topology for data center networks (DCNs). Many recent papers propose new energy-efficient techniques that reduce the power consumption of fat-tree DCNs by dynamically powering off idle network switches and links. However, fat-tree DCNs adopting those techniques still consume a significant amount of energy even when lightly loaded. In this paper, we examine the approach of merging...
There has been growing concern about energy consumption and environmental impact of data centers. Some pioneers begin to power data centers with renewable energy to offset carbon footprint. However, it is challenging to integrate intermittent renewable energy into data center power system. Grid-tied system is widely deployed in renewable energy powered data centers. But the drawbacks (e.g. Harmonic...
Nowadays, more and more the industry and market depend on cloud-based infrastructures for delivering IT services. To this aim cloud-based infrastructures are changing continuously, increasing their complexity especially for the management of cloud resources. Control and management of resources (e.g., virtual machines, VMs) are of paramount importance to adjust resources automatically allocated to...
In recent years, CAPTCHA has been used as a panacea against HTTP-based Distributed Denial of Service (DDoS) attacks. However, they also cause a lot of inconvenience to legitimate users. In this paper, we present a framework to exploit the synchronized behaviour of bots to exhaust web server resources. Clustering technique is used to form separate group of attackers and legitimate users. The clusters...
Preemptive-priority scheduling scheme based on M/M/n/m with different service ability of servers is proposed, in which arrival load of multiclass services increases proportionally and every service is able to choose a server with a certain probability. We set up the simulation model for understanding the transmission situation under various services and discuss in detail, which have been divided into...
In the last few years numerous connected vehicular applications and services have been developed. Most of them reside in the infotainment domain, but safety-critical use cases are within the scope of current realizations. As the performance of the wireless link has a major influence on the applications' reliability and functionality, it is important to consider its characteristics as early as possible...
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