Search

Fever is an evolutionary conserved response able to stimulate and boost both innate and adaptive immunity. Temperature variations in general modify the homeostatic setpoint such as blood flow in warm blooded animals and can change gene-expression patterns on the single cell level [1] . Neutrophils and dendritic cells (DCs) patrol tissues under various temperature levels and their effective encounter and response to ‘danger signals’ is key for optimal immune defence [2] . Still, the thermo-regulation of immune cell dynamics remains largely elusive. Here we show that the local temperature controls immune cell dynamics, such as shape changes, cell migration speed and persistence in 2D/2.5D/3D biomimetic micro-environments.

Dynamic, large social events with concurrent activities, in which participants view, but also provide high-quality content to other visitors, pose one of many challenges to multimedia delivery. Distributing content in such a situation is difficult, and requires strong support from the underlying network, in order to quickly respond to changes in supply and demand. A Flock is a flexible overlay built in a self-organized, decentralized manner, relying on a simple interest-property concept. In this paper, we use Flocks to build large overlays that are both content- and Quality-of-Service (QoS) aware, and show how they adapt their structure dynamically, depending on interests in available QoS. We evaluate their performance under churn and large scale failures through extensive simulations, and practical experiments under Internet conditions on the Planet Lab, and present a selection of our results.

The Peer-to-Peer Epi-Transport Protocol (PPETP) [1] is a peer-to-peer protocol designed for multimedia data distribution between end users. While its robustness and flexibility are attractive properties for multimedia cloud services, its lack of routing poses an issue if distant or specific nodes must be reached to, for example, provide service, or cloud interoperability. This paper describes an extension to the PPETP that provides fast routing based on Dynamic Linked Data Structures (DLDS) and hierarchical topology aggregation. We provide a hierarchical routing algorithm with low runtime complexity that offers PPETP several suitable paths needed to draw full benefit from its ability to send multiple reduced streams. DLDS are used to speed-up the routing of packets belonging to long-lasting streams, in periods where their paths do not change. We describe the challenges encountered implementing this solution, and evaluate its performance through simulation.

When dealing with multimedia delivery, scalability, efficiency and Quality of Service (QoS) are challenging features for today's networks. Overlay networks can compensate for the lack of control over the network routers, but for real-world applications overlay network performance is an issue. This paper presents an efficient solution for software implementation of overlay network nodes. A new, advanced Distributed Linked Data Structures (DLDS) schema has been developed to provide scalable per-flow resource reservation and fast, searchless routing/forwarding table lookup. This schema has been integrated in a new overlay network framework that features hierarchical dynamic routing and QoS estimation based on performance measures of the underlying network. The proposed technique has been implemented and tested in a large, realistic network simulation environment, and experimental results are presented.

This paper introduces a scalable approach for efficient, low-cost multi-level Quality of Service (QoS) estimation in large overlay networks (ON). We modify an existing distributed partitioning algorithm, and use it to create "QoS maps". QoS maps empower applications to quickly predict several QoS metrics for any given route, and to obtain multiple alternative routes to any target node in the ON. We show that our modifications of the partitioning algorithm permit the aggregation of large hubs, but still preserve the sub-linear runtime of the original heuristic. Simulations with large ONs are performed to evaluate the proposed approach and demonstrate its scalability. Finally, we outline our estimation algorithm that we use to predict QoS and perform QoS aware routing in any given ON.

Self-organizing overlay networks have received a lot of attention in the recent years. However, despite the popularity of content-aware and topology-aware overlay networks, surprisingly little research has been done to combine both approaches. In this paper, we create robust and flexible overlay networks that we call “Flocks”, which can be content-aware, topology-aware, or a combination of both. We model affinity with interests and properties and show the resulting overlay networks work in a decentralized, self-organizing way, and stabilize quickly.