A Tree-based Hierarchy Data Storage Framework in a Pervasive Space

Context data is important information for catching the behaviors of applications in a pervasive space. To effectively store huge amount of data, tree-like layered storage architecture is proposed, where the leaf nodes collect data from sensing devices. In order to integrate data from mobile devices, the related leaf nodes that get data from the same device should upload and store the data to the host node. This paper presents a deep study of the data storage problem and proposes a global algorithm GHS and an online algorithm DHS to dynamically select the host node, which reduces the communication cost significantly. This paper also gives the theoretical and experimental analysis of these algorithms, which shows both GHS and DHS are correct and effective

AccessAuth : Capacity-aware security access authentication in federated-IoT-enabled V2G networks

Vehicle-to-Grid (V2G) systems promoted by the federated Internet of Things (IoT) technology will be ubiquitous in the future; therefore, it is crucial to provide trusted, flexible and efficient operations for V2G services using high-quality measures for security and privacy. These can be achieved by access and authority authentication. This paper presents a lightweight protocol for capacity-based security access authentication named AccessAuth. Considering the overload probability and system capacity constraints of the V2G network domain, as well as the mobility of electric vehicles, the ideal number of admissible access requests is first calculated adaptively for each V2G network domain to actively achieve capacity-based access admission control. Subsequently, to provide mutual authentication and maintain the data privacy of admitted sessions, by considering whether there is prior knowledge of the trust relationship between the relevant V2G network domains, a high-level authentication model with specific authentication procedures is presented to enforce strict access authentication such that the sessions are conducted only by authorized requesters. Additionally, efficient session revocation with forward security and session recovery with no extra authentication delay are also discussed. Finally, analytical and evaluation results are presented to demonstrate the performance of AccessAuth

QoE-ensured Price Competition Model for Emerging Mobile Networks

The ubiquitous availability of devices such as smart phones, tablets, and other portable devices enables the collection of massive amounts of distributed data from the daily lives of citizens. These types of emerging mobile networks can provide new forms of valuable information that are currently not available on this scale via any traditional data collection methods. In such networks, price competition is the most important factor among the participants (mobile devices, Services Organizers and users) that highly affects their Quality-of-Experience (QoE). In this article, we first explain how a game theory model can depict social behavior, price competition and the evolutionary relationship among devices, Services Organizers (SOs) and users, and then we provide insights into understanding the price competition process of those participants in mobile networks. Finally, we outline several important open research directions

SmartRep: Reducing Flow Completion Times with Minimal Replication in Data Centers

To improve users\u27 experience, TCP short flows that are heavily used in interactive services should be completed as soon as possible. In current data centers, large flows and head-of-line blocking in switches hinder short flows from completion, which leads to long-tailed flow completion times (FCT). Replicating short flows with multiple equal-cost paths is a promising way to reduce FCT. However, the original flow and its replicated one are quite likely to be routed to the same path (ECMP hash collision), which increases both the mean and 99-percentile FCT significantly. What\u27s more, inadequate replication leaves many other less-congested equal-cost paths unused and limits the performance while excess replication degrades throughput of large flows. To solve these problems, we propose SmartRep, a scheme consisting of an efficient and effective traceroute based hash collision avoidance method and an algorithm to decide the optimal number of replicated flows for different short flows. SmartRep can be easily implemented in software and readily deployed in data centers. Extensive NS2 simulations show that our approach improves previous replication-based work by 25%-50% in both mean and 99th percentile FCT, and meanwhile imposes negligible impact on large flows.Date of Conference: 8-12 June 2015Conference Location: Londo

Active Data Replica Recovery for Quality-Assurance Big Data Analysis in IC-IoT

QoS-aware big data analysis is critical in Information-Centric Internet of Things (IC-IoT) system to support various applications like smart city, smart grid, smart health, intelligent transportation systems, and so on. The employment of non-volatile memory (NVM) in cloud or edge system provides good opportunity to improve quality of data analysis tasks. However, we have to face the data recovery problem led by NVM failure due to the limited write endurance. In this paper, we investigate the data recovery problem for QoS guarantee and system robustness, followed by proposing a rarity-aware data recovery algorithm. The core idea is to establish the rarity indicator to evaluate the replica distribution and service requirement comprehensively. With this idea, we give the lost replicas with distinguishing priority and eliminate the unnecessary replicas. Then, the data replicas are recovered stage by stage to guarantee QoS and provide system robustness. From our extensive experiments and simulations, it is shown that the proposed algorithm has significant performance improvement on QoS and robustness than the traditional direct data recovery method. Besides, the algorithm gives an acceptable data recovery time

AutoVNF: An Automatic Resource Sharing Schema for VNF Requests

Nowadays, network function virtualization (NFV) receives widespread concerns from the whole society for its promising application. The main challenge for the deployment of VNF that comes along is the resource allocation of demanded network services in NFV-based network infrastructures. Current offline resource mapping and scheduling algorithms are impractical for continuous VNF requests in data centers, because of the high time consumption. In this paper, we firstly present a resource sharing schema for VNF, including the automatic monitoring and fast switching mechanisms, which support multiple VNFs effectively share resource in one node. This VNF resource sharing schema improves the acceptance ratio of VNF requests as well as the system utilization. And then, we propose an automatic NFV resource allocation mechanism AutoVNF to optimize the VNF deployment. AutoVNF includes mapping and scheduling algorithms, which automatically allocates available nodes to VNF requests and schedules the execution of VNFs in one VNF queue. Simulations show that AutoVNF has a good performance on acceptance ratio, average flow time, and total cost compared with well-known scheduling algorithms

SRFabric: A Semi-Reconfigurable Rack Scale Topology

Rack scale design is a promising trend towards customized hardware design, where high density clusters of SoCs are integrated in the rack. One of the biggest challenges for rack scale computing is the interconnection network. Traditional data center topologies require too many ToR switches to support hundreds of SoCs, while distributed fabrics deliver a considerably high end-to-end latency and network oversubscription. Since no one topology fits all kinds of workloads, a flexible in-rack topology requires a careful redesign to dynamically adapt to diverse data center traffic within tight cost and space constraints in the rack. SRFabric is a semi-reconfigurable rack scale network topology that exploits the high path diversity, the cost-effectiveness of distributed fabrics, and the dynamic reconfigurability of circuit switches. This is accomplished by enabling multiple static ports and dynamic ports for each SoC. Leveraging the partial link reconfigurability, SRFabric is able to optimize its topology to dynamically adapt to various workload patterns. We further propose the design of SRFabric to decide the nearly optimal number of dynamic ports and static ports for expected communication density and performance. Extensive evaluations demonstrate that SRFabric can deliver lower average path length, i.e., 2.21 hops on average, and higher bisection bandwidth, i.e., up to 77% nonblocking bandwidth, and provide comparable performance with state-of-the-art strategy XFabric at a lower cost, i.e., XFabric costs up to 3 times more than that of SRFabric