Dynamic Unicast: Information-Centric Multi-hop Routing for Mobile Ad-hoc Networks

Abstract Information-centric networking (ICN) offers new perspectives on mobile ad-hoc communication because routing is based on names but not on endpoint identifiers. Since every content object has a unique name and is signed, authentic content can be stored and cached by any node. If connectivity to a content source breaks, it is not necessarily required to build a new path to the same source but content can also be retrieved from a closer node that provides the same content copy. For example, in case of collisions, retransmissions do not need to be performed over the entire path but due to caching only over the link where the collision occurred. Furthermore, multiple requests can be aggregated to improve scalability of wireless multi-hop communication. In this work, we base our investigations on Content-Centric Networking (CCN), which is a popular {ICN} architecture. While related works in wireless {CCN} communication are based on broadcast communication exclusively, we show that this is not needed for efficient mobile ad-hoc communication. With Dynamic Unicast requesters can build unicast paths to content sources after they have been identified via broadcast. We have implemented Dynamic Unicast in CCNx, which provides a reference implementation of the {CCN} concepts, and performed extensive evaluations in diverse mobile scenarios using NS3-DCE, the direct code execution framework for the {NS3} network simulator. Our evaluations show that Dynamic Unicast can result in more efficient communication than broadcast communication, but still supports all {CCN} advantages such as caching, scalability and implicit content discovery.

El paisaje cultural inisecular : construcción ad hoc de metodología para análisis de valor productivo del paisaje en la producción de vivienda masiva en Mendoza, Argentina

Fil: Zalazar, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas

MIRACLE’s Ad-Hoc and Geographical IR Approaches for CLEF 2006

This paper presents the 2006 Miracle team’s approaches to the Ad-Hoc and Geographical Information Retrieval tasks. A first set of runs was obtained using a set of basic components. Then, by putting together special combinations of these runs, an extended set was obtained. With respect to previous campaigns some improvements have been introduced in our system: an entity recognition prototype is integrated in our tokenization scheme, and the performance of our indexing and retrieval engine has been improved. For GeoCLEF, we tested retrieving using geo-entity and textual references separately, and then combining them with different approaches.

MIRACLE at Ad-Hoc CLEF 2005: Merging and Combining Without Using a Single Approach

This paper presents the 2005 Miracle’s team approach to the Ad-Hoc Information Retrieval tasks. The goal for the experiments this year was twofold: to continue testing the effect of combination approaches on information retrieval tasks, and improving our basic processing and indexing tools, adapting them to new languages with strange encoding schemes. The starting point was a set of basic components: stemming, transforming, filtering, proper nouns extraction, paragraph extraction, and pseudo-relevance feedback. Some of these basic components were used in different combinations and order of application for document indexing and for query processing. Second-order combinations were also tested, by averaging or selective combination of the documents retrieved by different approaches for a particular query. In the multilingual track, we concentrated our work on the merging process of the results of monolingual runs to get the overall multilingual result, relying on available translations. In both cross-lingual tracks, we have used available translation resources, and in some cases we have used a combination approach.

Analysis of ad hoc routing protocols for emergency and rescue scenarios.

A mobile ad hoc network MANET is a collection of wireless mobile nodes that can dynamically configure a network without a fixed infrastructure or centralized administration. This makes it ideal for emergency and rescue scenarios where information sharing is essential and should occur as soon as possible. This article discusses which of the routing strategies for mobile ad hoc networks: proactive, reactive and hierarchical, have a better performance in such scenarios. Using a real urban area being set for the emergency and rescue scenario, we calculate the density of nodes and the mobility model needed for validation. The NS2 simulator has been used in our study. We also show that the hierarchical routing strategies are beffer suited for this type of scenarios.

Assessment of troughput performance under NS2 in Mobile Ad Hoc Networks (MANETs)

Providing QoS in the context of Ad Hoc networks includes a very wide field of application from the perspective of every level of the architecture in the network.In order for simulation studies to be useful, it is very important that the simulation results match as closely as possible with the test bed results. In this Paper, we study the throughput performance (parameter QoS) in Mobile Ad Hoc Networks (MANETs) and compares emulated test bed results with simulation results from NS2 (Network Simulator). The performance of the Mobile Ad Hoc Networks is very sensitive to the number of users and the offered load. When the number of users/offered load is high then the collisions increase resulting in larger wastage of the medium and lowering overall throughput. The aim of this research is to compare the throughput of Mobile Ad Hoc Networks using three different scenarios: 97, 100 and 120 users (nodes) using simulator NS2. By analyzing the graphs in MANETs, it is concluded When the number of users o nodes is increased beyond the certain limit, throughput decreases.

Behavior of Ad Hoc routing protocols, analyzed for emergency and rescue scenarios, on a real urban area

A mobile Ad Hoc network (MANET) is a collection of wireless mobile nodes that can dynamically configure a network without a fixed infrastructure or central administration. This makes it ideal for emergency and rescue scenarios, where sharing information is essential and should occur as soon as possible. This article discusses which of the routing strategies for mobile MANETs: proactive, reactive or hierarchical, has a better performance in such scenarios. By selecting a real urban area for the emergency and rescue scenario, we calculated the density of nodes and the mobility model needed for the validation study of AODV, DSDV and CBRP in the routing model. The NS2 simulator has been used for our study. We also show that the hierarchical routing strategies are better suited for this type of scenarios.

Terminología bilingüe y documentación ad hoc para intérpretes de conferencias. Una aproximación metodológica basada en corpus

El intérprete de conferencias debe llevar a cabo un trabajo documental antes, durante y después de los eventos en los que presta sus servicios, independientemente de su subcompetencia extralingüística. Desafortunadamente, pocas son las propuestas metodológicas que se hayan planteado para que este profesional pueda realizar esta tarea de manera sistemática. En el presente artículo, repasamos algunos de los trabajos que se han referido a las posibilidades que tiene el intérprete de satisfacer sus necesidades informativas. Una vez reseñada la mencionada escasez de propuestas, presentamos, en un estudio de caso, una aproximación metodológica a este trabajo de documentación, fundamentada en la compilación de corpus paralelos ad hoc y la extracción terminológica en forma de glosarios.

La Oscilación del Mediterráneo Occidental: un patrón de teleconexión ad hoc para el este de la Península Ibérica

Se presenta el origen y la historia de la propuesta de un nuevo patrón de teleconexión, la Oscilación del Mediterráneo Occidental (WeMO), presentado por el autor en 2002 y aceptado internacionalmente en 2006. El índice de la WeMO, como diferencia de las presiones atmosféricas en superficie, previamente estandarizadas, de Cádiz-San Fernando y Padua, ofrece mejores correlaciones con la precipitación en la fachada oriental de la Península Ibérica que la NAO. En la actualidad medio centenar de artículos en revistas indexadas internacionalmente, de especialidades científicas diversas, no solo de Climatología, han hecho uso del nuevo patrón o lo han referenciado. Para la Península Ibérica, la WeMO es el patrón más explicativo de la precipitación torrencial desde el nordeste al sur.