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

Phylogenetic relationships among Staphylococcus species and refinement of cluster groups based on multilocus data

Background: Estimates of relationships among Staphylococcus species have been hampered by poor and inconsistent resolution of phylogenies based largely on single gene analyses incorporating only a limited taxon sample. As such, the evolutionary relationships and hierarchical classification schemes among species have not been confidently established. Here, we address these points through analyses of DNA sequence data from multiple loci (16S rRNA gene, dnaJ, rpoB, and tuf gene fragments) using multiple Bayesian and maximum likelihood phylogenetic approaches that incorporate nearly all recognized Staphylococcus taxa. Results: We estimated the phylogeny of fifty-seven Staphylococcus taxa using partitioned-model Bayesian and maximum likelihood analysis, as well as Bayesian gene-tree species-tree methods. Regardless of methodology, we found broad agreement among methods that the current cluster groups require revision, although there was some disagreement among methods in resolution of higher order relationships. Based on our phylogenetic estimates, we propose a refined classification for Staphylococcus with species being classified into 15 cluster groups (based on molecular data) that adhere to six species groups (based on phenotypic properties). Conclusions: Our findings are in general agreement with gene tree-based reports of the staphylococcal phylogeny, although we identify multiple previously unreported relationships among species. Our results support the general importance of such multilocus assessments as a standard in microbial studies to more robustly infer relationships among recognized and newly discovered lineages

Performance Evaluation of Wavelet-Coded OFDM on a 4.9 Gbps W-Band Radio-over-Fiber Link

Future generation mobile communications running on mm-wave frequencies will require great robustness against frequency selective channels. In this paper, we evaluate the transmission performance of 4.9 Gb/s wavelet-coded orthogonal frequency division multiplexing (OFDM) signals on a 10 km fiber plus 58 m wireless radio-over-fiber link using a mm-wave radio frequency carrier. The results show that a 2 × 128 wavelet-coded OFDM system achieves a bit-error rate of 1e-4 with nearly 2.5 dB less signal-to-noise ratio than a convolutional coded OFDM system with equivalent spectral efficiency for 8 GHz-wide signals with 512 subcarriers on a carrier frequency of 86 GHz. Our findings confirm the Tzannes’ theory that wavelet coding enables high diversity gains with a low complexity receiver and, most notably, without compromising the system’s spectral efficiency

Longitudinal genetic analyses of Staphylococcus aureus nasal carriage dynamics in a diverse population

Background: Staphylococcus aureus (SA) nasal colonization plays a critical role in the pathogenesis of staphylococcal infections and SA eradication from the nares has proven to be effective in reducing endogenous infections. To understand SA nasal colonization and its relation with consequent disease, assessment of nasal carriage dynamics and genotypic diversity among a diverse population is a necessity. Results: We have performed extensive longitudinal monitoring of SA nasal carriage isolates in 109 healthy individuals over a period of up to three years. Longitudinal sampling revealed that 24% of the individuals were persistent SA nasal carriers while 32% were intermittent. To assess the genetic relatedness between different SA isolates within our cohort, multi locus sequence typing (MLST) was performed. MLST revealed that not only were strains colonizing intermittent and persistent nasal carriers genetically similar, belonging to the same clonal complexes, but strain changes within the same host were also observed over time for both types of carriers. More highly discriminating genetic analyses using the hypervariable regions of staphylococcal protein A and clumping factor B virulence genes revealed no preferential colonization of specific SA strains in persistent or intermittent carriers. Moreover, we observed that a subset of persistent and intermittent carriers retained clinically relevant community-acquired methicillin-resistant SA (CA-MRSA) strains in their nares over time. Conclusions: The findings of this study provides added perspective on the nasal carriage dynamics between strains colonizing persistent and intermittent carriers; an area currently in need of assessment given that persistent carriers are at greater risk of autoinfection than intermittent carriers

Falcon/Kyber and Dilithium/Kyber Network Stack on Nvidia’s Data Processing Unit Platform

Commercially available quantum computers are expected to reshape the world in the near future. They are said to break conventional cryptographic security mechanisms that are deeply embedded in our today’s communication. Symmetric cryptography, such as AES, will withstand quantum attacks as long as the key sizes are doubled compared to today’s key lengths. Asymmetric cryptographic procedures, e.g. RSA, however are broken. It is therefore necessary to change the way we assure our privacy by adopting and moving towards post-quantum cryptography (PQC) principles. In this work, we benchmark three PQC algorithms, Falcon, Dilithium, and Kyber. Moreover, we present an implementation of a PQC stack consisting of the algorithms Dilithium/Kyber and Falcon/Kyber which use hardware accelerators for some key functions and evaluate their performance and resource utilization. Regarding a classic server-client model, the computational load of the Dilithium/Kyber stack is distributed more equally among server and client. The stack Falcon/Kyber biases the computational challenges towards the server, hence relieving the client of performing costly operations. We found that Dilithium’s advantage over Falcon is that Dilithium’s execution is faster while the workload to be performed is distributed equally among client and server, whereas Falcon’s advantage over Dilithium lies within the small signature sizes and the unequally distributed computational tasks. In a client server model with a performance limited client (i.e. Internet-of-Things - IoT - environments) Falcon could proof useful for it constrains the computational hard tasks to the server and leaves a minimal workload to the client. Furthermore, Falcon requires smaller bandwidth, making it a strong candidate for deep-edge or IoT applications

Falcon/Kyber and Dilithium/Kyber Network Stack on Nvidia’s Data Processing Unit Platform

Commercially available quantum computers are expected to reshape the world in the near future. They are said to break conventional cryptographic security mechanisms that are deeply embedded in our today’s communication. Symmetric cryptography, such as AES, will withstand quantum attacks as long as the key sizes are doubled compared to today’s key lengths. Asymmetric cryptographic procedures, e.g. RSA, however are broken. It is therefore necessary to change the way we assure our privacy by adopting and moving towards post-quantum cryptography (PQC) principles. In this work, we benchmark three PQC algorithms, Falcon, Dilithium, and Kyber. Moreover, we present an implementation of a PQC stack consisting of the algorithms Dilithium/Kyber and Falcon/Kyber which use hardware accelerators for some key functions and evaluate their performance and resource utilization. Regarding a classic server-client model, the computational load of the Dilithium/Kyber stack is distributed more equally among server and client. The stack Falcon/Kyber biases the computational challenges towards the server, hence relieving the client of performing costly operations. We found that Dilithium’s advantage over Falcon is that Dilithium’s execution is faster while the workload to be performed is distributed equally among client and server, whereas Falcon’s advantage over Dilithium lies within the small signature sizes and the unequally distributed computational tasks. In a client server model with a performance limited client (i.e. Internet-of-Things - IoT - environments) Falcon could proof useful for it constrains the computational hard tasks to the server and leaves a minimal workload to the client. Furthermore, Falcon requires smaller bandwidth, making it a strong candidate for deep-edge or IoT applications

Wireless intelligent sensors based in nanostructures with energy self-sufficiency to study the consequences of high temperatures in combustion motors

In this research are proposed the consequences of high temperatures in Internal Combustion Motors (ICM) as correlation of its performance according to give information of the ICM fault detector, which also can be useful for preventive maintenance. It was possible to achieve the proposed target because of it was designed a smart sensor based in nanostructures prepared over Anodic Aluminum Oxide (AAO) samples, which proportionated short response time and high robustness in the measurement tasks of the smart sensor, as well as, the designed sensor has the possibility to work by energy self-sufficiency and sending the measurement data to external users by wireless. In fact, it is waited that this research could be a support for researchers of ICM enhancement, who could look for new techniques of environment conditions cares in compensation to keep the balance between the useful energy obtained from ICM and the environment conditions, where are developed economical activities such as public transport or mining in Peru