Pedro García López

Cyclone: a novel design schema for hierarchical DHTs

Recent research efforts have improved the existing flat distributed hash tables to accommodate hierarchical structure. Nevertheless, many problems still remain to be solved regarding scalability issues, autonomous systems, connection degree, and network proximity. In this paper, we present a new hierarchical DHT called Cyclone that aims to solve the aforementioned issues with a near-optimal architecture. Cyclone provides optimal logarithmic routing hops without establishing unnecessary connection links to other nodes. Our approach follows a horizontal and uniform leaf-based approach that considerably reduces the overall number of links per node. Furthermore, Cyclone also offers a disjoint multipath routing scheme that benefits from network proximity and thus creates a more robust overlay infrastructure.

A novel methodology for constructing secure multipath overlays

One technique for securely delivering data in structured overlays is to increase the number of disjoint paths among peers. However, most overlays do not offer a substrate to accommodate multiple paths. The binary-equivalence relationship-based Cyclone methodology is decoupled from the overlay architecture, which insulates it from such limitations. It fortifies existing routing algorithms to defend against data-forwarding attacks.

ANTS framework for cooperative work environments

Designed to facilitate computer-supported cooperative work, ANTS overcomes the major deficiencies found in earlier groupware toolkits at the conceptual, architectural, and technological levels.

Dermi: a new distributed hash table-based middleware framework

We disscus about Dermi: a new distributed hash table-based middleware framework. Decentralized event remote method invocation (Dermi) is a peer-to-peer (P2P), decentralized event-based object middleware framework built on top of a structured overlay network. Using an event-notification service as the principal building block, Dermi makes three innovative contributions: P2P call abstractions, distributed interception, and a decentralized object-location service. We describe how to use these three pillars to build a wide variety of global-scale distributed applications and argue that Dermi is a solid foundational technology for future wide-area distributed component infrastructures.

Deploying Wide-Area Applications Is a Snap

The Structured overlay Networks Application Platform (Snap) is a J2EE-compatible wide-area Web application deployment infrastructure. Due to its structured peer-to-peer overlay network substrate, Snap offers three benefits to wide-area Web application deployment: easy adaptation of existent J2EE applications to a scalable network, a secure and decentralized deployment environment, and transparent embedded services, such as persistence, load balancing, fault tolerance, and edge computing

AGORA: an integrated approach for collaboration in MANETs

Nowadays, a growing interest exists for collaborative working environments. Proliferation of hand-held devices with networking capabilities, together with the free-of-charge characteristic have turned MANETs in a good alternative for group spontaneous collaboration. In order to reduce application development difficulty and adjust to MANET specific requirements, middleware approaches seem a good alternative for developing new collaboration applications. However, it is not easy to find a system which allows rapid application deployment. Building applications from scratch makes developing applications for ad hoc scenarios a difficult task. To cope with these requirements, we introduce AGORA, an integrated approach for collaborative applications in the MANET environment. AGORA provides an architecture with three well defined elements: a plug-in framework which simplifies the development of MANET collaborative applications; a collaboration middleware which offers communication and group services to application plug-ins, and finally, a routing layer in charge of providing efficient group communication.

Improving BitTorrent download times using community partners

In this paper we present the concept of community downloads as a mechanism to improve the overall performance of BitTorrent clients. A community is a group of nodes interested in the same content working cooperatively inside a swarm. To reinforce this cooperation among community nodes, we designed two new algorithms: Group Rarest-First (piece selection) and Group-Balanced Tit-for-tat (unchoke policy). Our algorithms treat the group as a big node, prioritizing community members and helping them to improve their download ratios. Our validation shows improvements in download time around 20% and up to 71% in different swarm scenarios.

SCOMET: Adapting Collaborative Working Environments to the MANET Scenario

In this short paper we present SCOMET, a system based on the peer-to-peer model that offers group management and various communication services for mobile ad-hoc collaboration. This system, which is under current development in the context of the IST-POPEYE project, aims to reduce communication impact by considering locality and cluster-based solutions. Besides, it offers services such as publish/subscribe, naming and communication primitives for building higher level applications.

SQS: Similarity Query Scheme for Peer-to-Peer Databases

Similarity search is a hot research topic on peer-to-peer systems. In this paper we present SQS, a similarity query scheme for peer-to-peer databases. In this work we provide a novel linearization mechanism that enables structured queries without the burden of a global information maintenance scheme. The system offers exact match and range searches to multidimensional data. SQS employs Cyclone, a hierarchical overlay that is able to build disjoint clusters in terms of network latency and enables data search load balancing by caching per cluster scheme. Finally, we show the good properties of SQS through representative simulation results.

COPS 2008 Workshop Final Report

An apparatus and a method for remotely indicating that a fax has been received. Received faxes are detected using an infrared emitter that sprays infrared energy into space that is open when no paper is present in the paper tray that receives incoming faxes at a fax machine, but which space is occupied by paper when a fax has been received. When there is no paper present in the paper tray, the infrared energy is lost in space. When there is paper present in the paper tray, the infrared energy is reflected back to and sensed by a photo transistor. When the photo transistor senses the presence of paper in the paper tray, a high-brightness light emitting diode is flashed to indicate that a fax has been received.