Machine learning models for traffic classification in electromagnetic nano-networks

The number of nano-sensors connected to wireless electromagnetic nano-network generates different traffic volumes that have increased dramatically, enabling various applications of the Internet of nano-things. Nano-network traffic classification is more challenging nowadays to analyze different types of flows and study the overall performance of a nano-network that connects to the Internet through micro/nanogateways. There are traditional techniques to classify traffic, such as port-based technique and load-based technique, however the most promising technique used recently is machine learning. As machine learning models have a great impact on traffic classification and network performance evaluation in general, it is difficult to declare which is the best or the most suitable model to address the analysis of large volumes of traffic collected in operational nano-networks. In this paper, we study the classification problem of nano-network traffic captured by micro/nano-gateway, and then five supervised machine learning algorithms are used to analyze and classify the nano-network traffic from traditional traffic. Experimental analysis of the proposed models is evaluated and compared to show the most adequate classifier for nano-network traffic that gives very good accuracy and performance score to other classifiers.This work was supported in part by the ‘‘Agencia Estatal de Investigación’’ of ‘‘Ministerio de Ciencia e Innovación’’ of Spain under Project PID2019-108713RB-C51/MCIN/AEI/10.13039/501100011033, and in part by the ‘‘Agència de Gestió d’Ajuts Universitaris i de Recerca’’ (AGAUR) of the ‘‘Generalitat de Catalunya’’ under Grant 2021FI_B2 00091.Postprint (published version

Contribution to the system architecture design for electromagnetic nano-network communications

(English) A nano-network is a communication network at the nano-scale between nano-devices. Nanodevices face certain challenges in functionalities, because of limitations in their processing capabilities and power management due to their nano-scale size. One of these challenges is the ability to perceive partial or full routing tables, which are the main decision makers for data routing in legacy communication networks. The reason is that creating and updating routing tables continuously require adequate processing power with sufficient memory and computing capabilities, which is not the case with nano- devices. Hence, these devices are expected to perform simple tasks, which equire different and novel approaches. In order to exploit the different functionalities of nano-machines, a set of nano-devices in a full nano-network needs to be managed and controlled using an appropriate architecture. This step will enable unrivaled applications in different fields. An Electromagnetic (EM) nano-network is a type of nano-communication that uses terahertz (THz) EM waves in communication. Nano-network has attracted increasing attention in recent years. Consequently, several developments have been achieved in the fabrication, communication and management of various EM nano network devices serving potential applications ranging from software- defined metamaterials, wireless robotic materials and body-centric communication. Such applications need uplink and downlink communication between the deployed nano-network and the external macro- world or the Internet through nano-interfaces. This causes heterogeneity and interoperability in different Internet of Nano-things (IoNT) applications, which become new challenges for nano-network communication. In this regard, dynamic, flexible and distributed micro/nano gateways can accommodate such sustainable issues and make the nano-network fully operational, regardless of the adopted application domain or the protocols used in communication. With the arrival of the Internet of Things (IoT), the use of the Internet has transformed, where various types of objects, sensors and devices can interact, making future networks connect nearly everything from traditional network devices to people. It is worth remarking that Software Defined Networking (SDN) and Network Function Virtualization (NFV) are two useful technologies for IoT. By outlining the way of combining SDN, NFV, IoT and fog computing technologies altogether, nano- network can overcome its challenges and limitations. The main objective of this thesis is to contribute to the system architectural design of EM nano- networks by developing an operational communication architecture to allow nano-machines to access the Internet. This communication architecture uses next-generation network technologies such as IoT and fog computing, besides well-known virtualization network technologies such as SDN and NFV to guarantee such accessibility. In addition, this communication architecture will provide added value to the data routing in the nano-network paradigm, whether inside the nano-domain or towards the macro- domain by providing virtualization and externalization of the complex routing decisions to be compiled externally on a powerful data center hosted on the cloud. The nano-machines will be able to access the cloud with the aid of smart hybrid devices called micro/nano-gateways, which provide two-way communication between nano-machines and the cloud. This two-way communication allows the end-user to easily control and manage a group of nanomachines expanding various applications in different fields. Moreover, it allows the nano-machines to store their measurements on the cloud, providing very large sets of data that are generated by a variety of nano-sensors/actuators forming big data, where Machine Learning (ML) approaches are used to perform complex analysis, intelligent judgments and creative problem solving on this big data extracting valuable information.(Español) Una nano-red es una red de comunicaciones a la escala nano, entre nano-dispositivos. Los nano-dispositivos afrontan determinados desafíos en funcionalidades, debido a las limitaciones de sui capacidad de procesado y la gestión de energía derivado de su nano-tamaño. Uno de estos desafíos es su capacidad de obtener una tabla de rutas parcial o completa, que es uno de los grandes puntos de decisión para el encaminamiento en redes de comunicaciones. La razón se encuentra en la dificultad y esfuerzo necesario para crear y actualizar continuamente las tablas, en términos de energía, memoria y capacidades de cómputo. En consecuencia, estos dispositivos únicamente efectuarán tareas sencillas, para las que se van a necesitar nuevas propuestas. Con el fin de aprovechar las funcionalidades de las nano-máquinas, un conjunto de nano-dispositivos en una nano-red completa necesita de mecanismos de gestión y control, a través de una arquitectura adecuada. Con ello, se podrán proporcionar nuevas aplicaciones en diversos campos. Una nano-red electromagnética (EM) es un tipo de nano-comunicación que emplea ondas en la banda de Teraherzios (THz). Las nano-redes han sido objeto de creciente atracción en los últimos años. En consecuencia, se han conseguido diversos desarrollos en la fabricación, comunicación y gestión con varios dispositivos en nano-redes EM, para aplicaciones desde metamateriales definidos por software, materiales robóticos wireless y comunicaciones en el cuerpo. Tales aplicaciones necesitan comunicaciones en sentido de subida y bajada, entre la nano-red desplegada y el macro-mundo externo, o Internet, a través de nano-interfaces. Ello causa heterogeneidad e inter-operabilidad en diversas aplicaciones de la Internet de las Nano-Things (IoNT), que constituyen nuevos desafíos para las comunicaciones en nano-redes. En este sentido, micro/nano gateways que sean dinámicos, flexibles y distribuidos, han de poder facilitar el acomodo de dichas aplicaciones y hacer que la red sea completamente operacional, independientemente del dominio de aplicaciones usadas o los protocolos de comunicaciones. Con la llegada de la Internet of Things (IoT), el uso de Internet se ha transformado, donde varios tipos de objetos, sensores y dispositivos pueden interactuar, haciendo que las futuras redes puedan conectar prácticamente cualquier cosa. Software Defined Networking (SDN) y Network Function Virtualization (NFV) son 2 tecnologías relevantes para IoT. Por medio de la combinación de SDN, NFV, IoT y fog computing, las nano-redes pueden solventar sus desafíos y limitaciones. El principal objetivo de esta tesis es contribuir al diseño de la arquitectura del sistema de las nano-redes EM por medio del desarrollo de una propuesta operacional que permita el acceso a Internet a las nano-máquinas Esta arquitectura de comunicaciones emplea las tecnologías de IoT y Fog Computing, además de las conocidas tecnologías de virtualización basadas en SDN y NFV. Además, la arquitectura de comunicaciones proporcionará un valor añadido al encaminamiento en el paradigma de la nano-red, ya sea dentro del nano-dominio o hacia el macro-dominio, por medio de virtualización y externalización de las decisiones complejas de encaminamiento, que serán compiladas externamente en un centro de datos situado en la nube. Las nano-máquinas serán capaces de acceder a la nube con la ayuda de dispositivos híbridos inteligentes denominados micro/nano gateways, que podrán proporcionar comunicaciones completas entre las nano-máquinas y la nube. De esta manera, el usuario final podrá controlar y gestionar un grupo de nano-máquinas y facilitar la creación de aplicaciones en diversos campos. Además, permite a las nano-máquinas almacenar su información en la nube, proporcionando grandes conjuntos de información, big-data, donde estrategías de Machine Learning (ML) se pueden usar para resolver diversos problemas complejos.Postprint (published version

Probability-based path discovery protocol for electromagnetic nano-networks

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/One of the major challenges for nano-network is the forfeit of communication protocols to exploit the potential communication between nano-machines forming fully operational nano-network. Because nano-machines face some restrictions such as limited processing power and confined computing capabilities, up-to-date nano-machines cannot perceive partial or full routing tables, which are the main decision-makers for data routing in legacy communication networks. The reason is that creating and updating routing tables continuously require adequate processing power with sufficient memory and computing capabilities, which is not the case of nano-nodes. So, new innovative routing schemes have to be proposed for nano-networks to deal with such extremely low resources. This paper focuses on decoupling the routing intelligence from nano-network towards a computational architecture using Software Defined Networking (SDN) and Network Function Virtualization (NFV) technologies by externalizing routing decisions and complex computations from nano-nodes to be fully compiled externally. Moreover, the paper proposes a probability-based path discovery protocol denoted by (PBPD) for electromagnetic nano-nodes suitable for dynamic nano-network applications. The performance of the proposed protocol is evaluated and compared with other routing protocols discussed in the literature. The proposed scheme provides low energy consumption inside nano-nodes and low computational complexity thanks to SDN/NFV system.This work has been supported by the ”Ministerio de Economía y Competitividad” of the Spanish Government under project TEC2016-76795-C6-1-R, AEI/FEDER UE and ”Agència de Gestió d’Ajuts Universitaris i de Recerca” (AGAUR) of the ”Generalitat de Catalunya” under FI-AGAUR grant number 2019FI-B00056.Peer ReviewedPostprint (author's final draft

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research