How Graph Theory can help Communications Engineering

International audienceWe give an overview of different aspects of graph theory which can be applied in communication engineering, not trying to present immediate results to be applied neither a complete survey of results, but to give a flavor of how graph theory can help this field. We deal in this paper with network topologies, resource competition, state transition diagrams and specific models for optical networks

OTIS-Based Multi-Hop Multi-OPS Lightwave Networks

International audienceAdvances in optical technology, such as low loss Optical Passive Star couplers (OPS) and the possibility of building tunable optical transmitters and receivers have increased the interest for multiprocessor architectures based on lightwave networks because of the vast bandwidth available. Many research have been done at both technological and theoretical level. An essential effort has to be done in linking those results. In this paper we propose optical designs for two multi-OPS networks: the single-hop POPS network and the multi-hop stack-Kautz network; using the Optical Transpose Interconnecting System (OTIS) architecture, from the Optoelectronic Computing Group of UCSD. In order to achieve our result, we also provide the optical design of a generalization of the Kautz digraph, using OTIS

Unfolding Rates for the Diffusion-Collision Model

In the diffusion-collision model, the unfolding rates are given by the likelihood of secondary structural cluster dissociation. In this work, we introduce an unfolding rate calculation for proteins whose secondary structural elements are $\alpha$-helices, modeled from thermal escape over a barrier which arises from the free energy in buried hydrophobic residues. Our results are in good agreement with currently accepted values for the attempt rate.Comment: Shorter version of cond-mat/0011024 accepted for publication in PR

Topologies for Optical Interconnection Networks Based on the Optical Transpose Interconnection System

International audienceMany results exist in the literature describing technological and theoretical advances in optical network topologies and design. However, an essential effort has yet to be done in linking those results together. In this paper, we propose a step in this direction, by giving optical layouts for several graph-theoretical topologies studied in the literature, using the Optical Transpose Interconnection System (OTIS) architecture. These topologies include the family of Partitioned Optical Passive Star (POPS) and stack-Kautz networks as well as a generalization of the Kautz and de Bruijn digraphs

How Graph Theory can help Communications Engineering

International audienceWe give an overview of different aspects of graph theory which can be applied in communication engineering, not trying to present immediate results to be applied neither a complete survey of results, but to give a flavor of how graph theory can help this field. We deal in this paper with network topologies, resource competition, state transition diagrams and specific models for optical networks

Effectiveness of a participatory approach for collection of economic data in aquaculture systems at farm level in Brazil.

This paper aims to evaluate the effectiveness of a participatory approach which is currently being applied by the Brazilian Agricultural Research Corporation (Embrapa) and Brazilian Confederation of Agriculture and Livestock (CNA) in aquaculture sector in Brazil

Topologies for Optical Interconnection Networks Based on the Optical Transpose Interconnection System

International audienceMany results exist in the literature describing technological and theoretical advances in optical network topologies and design. However, an essential effort has yet to be done in linking those results together. In this paper, we propose a step in this direction, by giving optical layouts for several graph-theoretical topologies studied in the literature, using the Optical Transpose Interconnection System (OTIS) architecture. These topologies include the family of Partitioned Optical Passive Star (POPS) and stack-Kautz networks as well as a generalization of the Kautz and de Bruijn digraphs

Evaluation of IEEE802.15.4g for Environmental Observations

International audienceIEEE802.15.4g is a low-power wireless standard initially designed for Smart Utility 1 Networks, i.e. for connecting smart meters. IEEE802.15.4g operates at sub-GHz frequencies to offer 2 2-3× longer communication range compared to its 2.4 GHz counterpart. Although the standard 3 offers 3 PHYs (FSK, OFDM and O-QPSK) with numerous configurations, 2-FSK at 50 kbps is the 4 mandatory and most prevalent radio setting used. This article looks at whether IEEE802.15.4g can 5 be used to provide connectivity for outdoor deployments. We conduct range measurements using 6 the totality of the standard (all modulations with all further parametrization) in the 863-870 MHz 7 band, within four scenarios which we believe cover most low-power wireless outdoor applications: 8 line of sight, smart agriculture, urban canyon, and smart metering. We show that there are radio 9 settings that outperform the "2-FSK at 50 kbps" base setting in terms of range, throughput and 10 reliability. Results show that highly reliable communications with data rates up to 800 kbps can 11 be achieved in urban environments at 540 m between nodes, and the longest useful radio link is 12 obtained at 779 m. We discuss how IEEE802.15.4g can be used for outdoor operation, and reduce 13 the number of repeater nodes that need to be placed compared to a 2.4 GHz solution