COVID‑19 mitigation by digital contact tracing and contact prevention (app‑based social exposure warnings)

A plethora of measures are being combined in the attempt to reduce SARS-CoV-2 spread. Due to its sustainability, contact tracing is one of the most frequently applied interventions worldwide, albeit with mixed results. We evaluate the performance of digital contact tracing for different infection detection rates and response time delays. We also introduce and analyze a novel strategy we call contact prevention, which emits high exposure warnings to smartphone users according to Bluetooth-based contact counting. We model the effect of both strategies on transmission dynamics in SERIA, an agent-based simulation platform that implements population-dependent statistical distributions. Results show that contact prevention remains effective in scenarios with high diagnostic/response time delays and low infection detection rates, which greatly impair the effect of traditional contact tracing strategies. Contact prevention could play a significant role in pandemic mitigation, especially in developing countries where diagnostic and tracing capabilities are inadequate. Contact prevention could thus sustainably reduce the propagation of respiratory viruses while relying on available technology, respecting data privacy, and most importantly, promoting community-based awareness and social responsibility. Depending on infection detection and app adoption rates, applying a combination of digital contact tracing and contact prevention could reduce pandemic-related mortality by 20–56%.publishedVersionFil: Soldano, Germán J. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Soldano, Germán J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina.Fil: Fraire Juan A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Fraire Juan A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Fraire Juan A. Saarland University. Saarland Informatics Campus; Saarbrücken, Germany.Fil: Finochietto, Jorge M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Finochietto, Jorge M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Quiroga; Rodrigo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Quiroga; Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina

Comparison in power consumption of static and dynamic WDM networks

This is the author’s version of a work that was accepted for publication in Optical Switching and Networking. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Optical Switching and Networking, 8, 3 (2011) DOI: 10.1016/j.osn.2011.03.005Greening of the Internet has become one of the main challenges for the research community. Optical networks can provide an energy efficient solution, but it has become crucial to assess its power efficiency. In this context, dynamic operation of WDM networks is expected to provide significant power savings when compared to static operation; however, its benefits need to be evaluated to determine its actual impact and to analyze future trends. In this paper, a general framework for evaluating energy consumption in WDM networks is introduced. The proposed framework enables the analysis of different node architectures, link capacities and network topologies. In particular, the case of three different node architectures is discussed and compared. Results show that dynamic operation can significantly reduce power consumption when either the traffic load is below 0.4 or when short-reach transponders consume significantly lower power than long-reach ones. In the latter case, dynamic operation shows significant benefits compared to the static case for traffic loads higher than 0.4. It is also shown that the transponders of the input/output stage of the nodes determine the benefit–in terms of power consumption–of an eventual migration from static to dynamic architecture rather than the transponders of the interface between the WDM and higher layers.This work was supported by the UAM-Banco Santander CEAL grant, the “Juan de la Cierva” postdoctoral research grant from The Spanish Ministry Ministerio de Ciencia e Innovación (MICINN), DGIP-UTFSM Scientific Initiation Scholarship, Conicyt and DGIP-UTFSM Scholarships for PhD studies, USM Project 23.09.70 and Centro Científico Tecnológico Valparaíso Project #FB/28AB/10

Enhanced crankback signaling for multi-domain IP/MPLS networks

Multi-domain traffic engineering is a very challenging problem area and crankback signaling offers a very promising solutions framework herein. Although some initial crankback studies have been done, there is still significant latitude for improving multi-domain crankback performance. Along these lines, this paper studies realistic IP/MPLS multi-domain networks and proposes a novel solution for joint intra/interdomain signaling crankback. Namely, dynamic intra-domain link-state routing information is coupled with available inter-domain path/distance vector routing state to improve the overall search process. Mechanisms are also introduced to limit crankback overheads and delays. The performance of the proposed solution is then analyzed using simulation and compared against hierarchical inter-domain routing strategies as well as another crankback scheme.

Scheduling Variable-Size Packets in the DAVID Metropolitan Area Network

Abstract — DAVID is a research project sponsored by the European Union aimed at the design of an optical packet-switched network for the transport of IP traffic. The DAVID network has a two-level hierarchical structure, with a backbone of optical packet routers inter-connected in a mesh, and metropolitan areas served by sets of optical rings interconnected by passive memoryless devices called Hubs. The paper focuses on the metropolitan area network and its components: the nodes and the Hub. Access is regulated by a dynamic time-division multiple-access scheme allocating slots in sets of wavelengths that provide multi-channel pipes among ring pairs. This paper proposes a new resource allocation scheme capable of transporting variable-size packets without segmentation into fixed-size data units. Resource sharing among nodes is granted by two scheduling algorithms running o

Can simple optical switching fabrics scale to terabit per second switch capacities?

The design of fabrics for terabit packet switches and routers needs to consider the limitations imposed by electronic technologies. In particular, attention has to be paid to information density and to power consumption and dissipation, as well as to power supply and footprint requirements. Optical technologies can overcome some of these limitations. We analyze the use of optical fabrics to interconnect line cards in terabit packet switches and routers. For this purpose, single-plane and multiplane optical interconnection architectures are proposed that exploit wavelength agility at line cards to implement the required switching functionality. The physical-layer scalability and feasibility of these architectures are studied by using realistic models, mostly based on the characteristics of commercially available opto-electronic devices. As a result, the considered architectures can be characterized in terms of power budget and signal-to-noise ratio, enabling the computation of the maximum achievable port count and aggregate switching capacity. Our results show that aggregate capacities of the order of a few terabits per second are possible in very simple optical switching fabrics and that the multiplane architectures permit a complexity trade-off between the wavelength and space domains, making the overall design more feasible