Approximation to a behavioral model for estimating traffic aggregation scenarios

This article provides a comparison among different methods for estimating the aggregation of Internet traffic resulting from different users, network-access types and corresponding services. Some approximate models usually used as isolated methods are combined with a temporally scaled ON-OFF model with binomial approximations. The aggregation problem is solved using a new form of parameterization based on the composition of the source traffic accordingly to the concrete characteristics of the users, the accesses and the services. This is a new concept, called CASUAL, included within an overall network planning methodology for the design and dimensioning of Next Generation Internet

Simplified methods for next generation IP access networks planning

The scope of this paper is to derive a set of simple formulas providing a traffic aggregation in important points of an Internet access networks. The paper shows that the resources associated to the access network depend on user type-, technology and service parameter. Existing calculation methodologies applies on individual approximations whereas this proposal exposes the combined application of these individual and wellknown approximations providing a scheme of generic dimensioning formulas. The dimensioning formulas for a generic applications are derived for the three main levels: connection, session and burst level, and the traffic aggregation is considered through three different and combined variables describing users, accesses and services forming a cube with three axes. The adaptation of corresponding parameters following the different axes allows the calculation of complete access network traffic scenarios, grouped by the so called CASUAL concept: Cube of Accesses / Services / Users. A set of CASUAL based tools allows an estimation of the aggregated traffic in different access points as multiplexers, IP point of presence or edge routers

Contribución al desarrollo de herramientas estratégicas para el diseño, dimensionado y evaluación de redes de telecomunicación de banda ancha

RESUMEN: Internet ha supuesto el despegue de las redes de conmutación de paquetes, las ha convertido en un medio al que todo el mundo quiere acceder, y ha obligado a replantear todas las previsiones que manejaban los operadores sobre el tráfico que iban a soportar sus redes en cada una de sus partes: el acceso, la agregación y la dorsal. Precisamente, la evaluación de estas y otras situaciones deben estar incluidas en el proceso de diseño y planificación de cualquier red, en lo que se ha denominado planificación estratégica. La estimación de la demanda de tráfico resulta especialmente importante porque permite al operador anticiparse a situaciones de congestión y bloqueo de la red. Utiliza herramientas de modelado del tráfico, bien para su cálculo analítico o para su estudio mediante simulación, y al ser una herramienta fundamental, existe un extenso catálogo de modelos de tráfico: genéricos y particularizados, de fuentes individuales y de redes completas, de elementos de interconexión y de enlaces. En esta Tesis, se han analizado los diferentes modelos existentes y se ha desarrollado un nuevo modelo que tiene en cuenta el comportamiento del tráfico desde su preparación por parte de la capa de aplicación, hasta su inserción en la capa física. El modelo propuesto parte de la solución ON-OFF tradicional, aunque aplicado a tres niveles diferentes (conexión, sesión y ráfaga), de forma que cada estado ON se encuentra modulado por el modelo correspondiente a la capa inferior. Como alternativa más simple, surgen los modelos multifuente, que intentan introducir el efecto de la interacción entre las diferentes fuentes, también conocido como agregación. Para considerar este caso, se ha realizado un estudio de modelos específicos para su aplicación a puntos de agregación, especialmente los situados en la red de acceso, al ser ésta la parte de la red que más alto coste presenta en su implementación. Partiendo del modelo ON-OFF para una sola fuente, se ha propuesto una variante multifuente, que aprovecha las propiedades de la función de distribución binomial para realizar el cálculo del tráfico agregado por un número determinado de fuentes. El resultado ha sido comparado mediante la observación de flujos reales, tal como propone la teoría del Network Calculus, y que ha sido evaluada y aplicada en este trabajo con ejemplos prácticos que se han incluido en el documento. El estudio realizado en esta Tesis concluye que el tráfico de fuente está condicionado a tres premisas fundamentales: el usuario, el servicio y la tecnología de acceso, de donde surge un nuevo concepto que especifica de forma sistemática y ordenada todas las variaciones, denominada CASUAL (Cubo de Acceso/Servicios/Usuarios de Asignación Libre) y ha sido aplicada en una herramienta realizada a su efecto, junto con los modelos de tráfico de fuente propuestos.ABSTRACT: Internet has been the catalyst of the development of packet switched networks, which have become the resource which everyone wants to access. As a consequence, the operators need to recalculate all their forecasts about the traffic to be transported by their networks. In fact, the evaluation of these and other situations should be included within the design and planning phases of any network, in the so called strategic planning overall process. Traffic demand estimation is particularly interesting, since it allows the operator to anticipate bottlenecks and blocking situations of the network. It uses traffic modelling tools, either for their analytical or simulation-based study. Since they have become an essential tool, there is a wide range of traffic models: generic and particularized, for individual sources and complete networks, for interconnection elements and links. In this thesis, we have analyzed the different models and have developed a new model that takes into account traffic patterns from preparation by the application layer to its insertion into the physical layer. The proposed model is based on the traditional on-off solution, but applied to three different levels (connection, session and burst), so that each ON state is modulated by the model corresponding to the bottom layer. As a simpler alternative, multisource models emerge, seeking to introduce the effect of the interaction between different sources, also known as aggregation. To consider this case, it has made a study of specific models for application to aggregation points, especially those located in the access network, as this is the part of the network that has higher cost in implementation. Based on the ON-OFF model for a single source, is a proposed multi-source variant, which exploits the properties of the binomial distribution function for the calculation of the aggregate traffic for a specified number of sources. The result has been compared by observation of actual flows, as proposed by the theory of Network Calculus, and has been evaluated and implemented in this work with practical examples that are included in the document. The study in this thesis concludes that the traffic source is conditioned on three fundamental premises: the user, service and technology access, where there was a new concept that specifies a systematic and orderly all the variations, called CASUAL (Cube of Access / Services / Users with Free Allocation) and has been implemented in a tool made of its effect, along with the traffic source models proposed

Protocolos para interconexión de redes (G842). Febrero 2013

Grado en Ingeniería de Tecnologías de Telecomunicació

On the use of Blockchain to enable a highly scalable Internet of Things Data Marketplace

As data becomes the new fuel of the economy and a key asset to address our societal challenges, we cannot afford to have the data of businesses, public sector and individuals stored and kept unexploited or, what is worse, exploited by others that actually have the resources and capacity to do it. This is affecting not only our economic performance but also our security, safety and sovereignty. Among the plethora of data sources that exist nowadays, the Internet of Things (IoT) is recognised as a game-changer technology that expands its applicability to a huge variety of domains. Its main asset is, precisely, the data that the myriad of sensors embedded in the environment are constantly generating. The diffusion of platforms for IoT data sharing and monetisation is one of the key success factors which may help to drive the data economy and industrial transformation. In this paper, we are presenting a data sharing platform based on Blockchain, so-called Blockchain-based IoT Data Marketplace (BIDM) over which data producers and data consumers are able to share data in a decentralised and trustworthy manner. The BIDM enables a data marketplace where owners of IoT infrastructures can expose the observations that their devices generate while retaining control over who accesses each observation and directly getting revenues according to the price they have set. The evaluation that we have carried out of the BIDM's behaviour and performance in terms of operational execution times and scalability has been the basis for the discussion that we are presenting on the shortcomings that are typically associated with the use of Blockchain technologies as enablers for data marketplaces. This discussion also includes the evaluation of the challenges that must be considered for the creation of secure and interoperable Data Spaces based on Blockchain.This work was supported by the Spanish State Research Agency (AEI) by means of the project FIERCE ‘‘Future Internet Enabled Resilient CitiEs’’ under Grant Agreement No. RTI2018-093475-A-I00 and the project SITED ‘‘Semantically-enabled Interoperable Trustworthy Enriched Data-spaces’’ under Grant Agreement No. PID2021-125725OB-I00

Lessons learned from a sporadic FUSopathy in a young man: a case report

Abstract Background In frontotemporal dementia (FTD) spectrum, younger patients may correspond to fusopathy cases, and cognitive decline could be rapidly progressive. We present a clinical and neuropathological description of a patient. Case presentation A 37-year-old man, without a family history of neurodegenerative diseases, was brought by his family to consult for dysarthria and behavioural change. Initial exploration showed spastic dysarthria and disinhibition. He progressively worsened with a pseudobulbar syndrome, right-lateralized pyramidal signs, left hemispheric corticobasal syndrome and, finally, lower motor neuron signs in his right arm. He died four years after the initiation of the syndrome from bronchopneumonia. Laboratory tests (including blood and cerebrospinal fluid (CSF)) were normal. Magnetic resonance imaging (MRI) and fluorodeoxyglucose-containing positron emission tomography (PET-18F-FDG) showed left fronto-insular atrophy and hypometabolism. Subsequently, 123I-ioflupane (DaT-SCAN®) single-photon emission computed tomography (SPECT) was pathologic, manifesting bilaterally decreased activity with greater affection on the left side. Only a third electromyogram (EMG) detected denervation in the last year of evolution. No mutations were found in genes such as Tau, progranulin, C9orf72, FUS, TDP-43, CHMP2B, or VCP. In necropsy, severe frontotemporal atrophy with basophilic neuronal cytoplasmic and intranuclear inclusions, negative for tau and TAR DNA binding protein 43 (TDP-43), but positive for fused in sarcoma (FUS) consistent with specifically basophilic inclusions body disease (BIBD) type was found. Conclusions In patients affected by FTD, particularly the youngest, with rapidly progressive decline and early motor affection, fusopathy must be suspected. These cases can include motor signs described in the FTD spectrum. Lower motor neuron affection in EMG could be detected late

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

Objectives: This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP). Methods: Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately. Results: We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors. Conclusion: Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective

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