Data center connectivity by 6G wireless systems

Wireless connectivity and photonic-wireless links in data centers allow fast deployment and dynamic reconfigurability. Technological advances in millimeter and sub-THz communications will soon go beyond 5G and trigger 6G systems. We present how data centers could benefit from such 6G technologies, particularly in assuring flexibility and adaptability, without compromising scalability

Photonic Integrated Circuits for mmW Systems

The bandwidth of wireless networks needs to grow exponentially over the next decade, due to an increasingly interconnected and smart environment. By 2020 there will be 50 billion devices connected to the internet. Low-cost, compact and broadband wireless transceivers will be required. The current WiFi frequency bands do not have enough capacity and wireless communication needs to move to the millimeter-wavelength or sub-terahertz range. The use of all-electronic solutions becomes increasingly prohibitive, though, at these higher frequencies. Microwave photonic technology o®ers the bandwidth and carrier frequencies required for high- capacity wireless networks and remote sensing applications. In this paper, we will introduce our e®orts to leverage the advantages of microwave photonics and photonic integrated circuits to de- velop low-cost and ubiquitous wireless technology enabled by silicon photonics based transceivers

Throughput Performance Evaluation of Multiservice Multirate OCDMA in Flexible Networks

\u3cp\u3eIn this paper, new analytical formalisms to evaluate the packet throughput of multiservice multirate slotted ALOHA optical code-division multiple-access (OCDMA) networks are proposed. The proposed formalisms can be successfully applied to 1-D and 2-D OCDMA networks with any number of user classes in the system. The bit error rate (BER) and packet correct probability expressions are derived, considering the multiple-access interference as binomially distributed. Packet throughput expressions, on the other hand, are derived considering Poisson, binomial, and Markov chain approaches for the composite packet arrivals distributions, with the latter defined as benchmark. A throughput performance evaluation is carried out for two distinct user code sequences separately, namely, 1-D and 2-D multiweight multilength optical orthogonal code (MWML-OOC). Numerical results show that the Poisson approach underestimates the throughput performance in unacceptable levels and incorrectly predicts the number of successfully received packets for most offered load values even in favorable conditions, such as for the 2-D MWML-OOC OCDMA network with a considerably large number of simultaneous users. On the other hand, the binomial approach proved to be more straightforward, computationally more efficient, and just as accurate as the Markov chain approach.\u3c/p\u3

Conocimiento y poder: la asimetría de intereses de los médicos colombianos y de Rockefeller en la construcción del concepto de fiebre amarilla selvática, 1907-1938

Este estudio examina las asimetrías entre los diferentes intereses de los funcionarios y médicos que trabajaron para la Fundación Rockefeller y sus contrapartes colombianas en el desarrollo y consolidación del concepto de 'fiebre amarilla de la selva', a diferencia de la conocida forma urbana de fiebre amarilla. Exploramos las respuestas de investigación a una variedad de brotes de enfermedades en Colombia en el contexto de las campañas de Rockefeller contra la fiebre amarilla, desde la descripción inicial de Roberto Franco de la 'fiebre amarilla de los bosques' en 1907 hasta la consolidación del concepto. de 'fiebre amarilla de la jungla' de Fred Soper en 1938.This study examines the asymmetries among the different interests of officials and medical doctors who worked for the Rockefeller Foundation and their Colombian counterparts in the development and consolidation of the concept of “jungle yellow fever,” as distinguished from the known urban form ofyellow fever. We explore the research responses to a variety of disease outbreaks in Colombia in the context of the Rockefeller campaigns against yellow fever, from the time of Roberto Franco’s initial description of “yellow fever of the forests” in 1907 until the consolidation of the concept of “jungle yellow fever” by Fred Soper in 1938.Cette étude examine las divergencias de interes parmi les fonction-naires et les meddecins qui ont travaillé pour la Fondation Rockefeller et sa filiale colombienne dans le développement et la consolidation du concept de «la fièvre jaune selvatique», qui diffère de la forme connue de fièvre jaune urbaine. Nous explorons les réponses de recherche à une variété d'irruptions de maladie en Colombie dans le contextte des campagnes de la Fondation Rockefeller con-tre la fìèvre jaune depuis la description initle de la «fièvre jaune des forêts» de Roberto Franco en 1907 jusqu ' à la consolidación del concepto de fièvre jaune sel-vatique por Fred Soper en 1938

Empirical multichannel power consumption model for erbium-doped fiber amplifiers

In this paper we report on the first experimental power consumption analysis and model of single and multi-stage booster erbium-doped fiber amplifiers (EDFAs) with automatic gain control (AGC), accounting for channel number dependency. Results show that the amount of channels being amplified simultaneously contributes significantly, up to 48%, to the total power consumption due to the circuitry used for controlling the EDFA. As the number of simultaneous amplified WDM channels in high capacity long and medium reach transmission links reflects closely traffic patterns generated by end-users, it is relevant to study channel number dependent power consumption for devising EDFA power efficient control and design

High-speed wireless access in forested rural areas using analog radio-over-fiber technology

A low complexity Ka-band hybrid photonic-wireless link based on a commercial SFP+ module is demonstrated, offering an economical and efficient solution for access provisioning to rural areas. A rain forest environment is emulated and low BER is achieved

FSO-CDMA Systems Supporting end-to-end Network Slicing

A new flexible, secure FSO-CDMA system supporting end-to-end network resource slicing is proposed and investigated. New mathematical formalisms considering distinct turbulence conditions are derived. The system supports different applications, use cases, and traffic requirements

FSO-CDMA Systems Supporting end-to-end Network Slicing

A new flexible, secure FSO-CDMA system supporting end-to-end network resource slicing is proposed and investigated. New mathematical formalisms considering distinct turbulence conditions are derived. The system supports different applications, use cases, and traffic requirements

Chemical modeling of acid-base properties of soluble biopolymers derived from municipal waste treatment materials

This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials