QoSatAr: a cross-layer architecture for E2E QoS provisioning over DVB-S2 broadband satellite systems

This article presents QoSatAr, a cross-layer architecture developed to provide end-to-end quality of service (QoS) guarantees for Internet protocol (IP) traffic over the Digital Video Broadcasting-Second generation (DVB-S2) satellite systems. The architecture design is based on a cross-layer optimization between the physical layer and the network layer to provide QoS provisioning based on the bandwidth availability present in the DVB-S2 satellite channel. Our design is developed at the satellite-independent layers, being in compliance with the ETSI-BSM-QoS standards. The architecture is set up inside the gateway, it includes a Re-Queuing Mechanism (RQM) to enhance the goodput of the EF and AF traffic classes and an adaptive IP scheduler to guarantee the high-priority traffic classes taking into account the channel conditions affected by rain events. One of the most important aspect of the architecture design is that QoSatAr is able to guarantee the QoS requirements for specific traffic flows considering a single parameter: the bandwidth availability which is set at the physical layer (considering adaptive code and modulation adaptation) and sent to the network layer by means of a cross-layer optimization. The architecture has been evaluated using the NS-2 simulator. In this article, we present evaluation metrics, extensive simulations results and conclusions about the performance of the proposed QoSatAr when it is evaluated over a DVB-S2 satellite scenario. The key results show that the implementation of this architecture enables to keep control of the satellite system load while guaranteeing the QoS levels for the high-priority traffic classes even when bandwidth variations due to rain events are experienced. Moreover, using the RQM mechanism the user’s quality of experience is improved while keeping lower delay and jitter values for the high-priority traffic classes. In particular, the AF goodput is enhanced around 33% over the drop tail scheme (on average)

Active interventions in hypercholeteroloemia patiens with high cardiovascular risk in primary care

Introduction: Hypercholesterolemia is a major modifiable risk factors for cardiovascular disease (CVD). Its reduction reduces morbidity and mortality from ischemic heart disease and CVD in general, primary prevention and secondary prevention especially. Objective: To determine whether a notarized and intensive clinical practice can overcome inertia and achieve the therapeutic goal (OT) LDL-C &lt;100 mg &lt;dL in high-risk patients attended in Primary Care (PC) in our country. Methodology: epidemiological, prospective, multicenter study conducted in centers of different ACs By AP consecutive sampling 310 patients at high cardiovascular risk (diabetic or established CVD) previously treated with statins, which did not reach the OT included c-LDL. Results: The study subjects had a mean age of 65.2 years, of which 60.32% were male. The 41.64% had a previous EVC, acute myocardial infarction (20.33%), angina (16.07%), stroke /TIA (9.19%), arthropathy (5.25%), diabetes (70 , 87%), hypertension (71.01%), and abdominal obesity (69.62%). The 43.57% (95% CI: 37,21; 50,08) of patients who performed the 2nd visit (241) got the OT. 62.50% (95% CI: 55.68, 68.98) of those who took the 3rd (216) got the OT. Finally, 77.56% (95% CI: 72.13, 83.08) patients who performed the last visit (205) got the OT. Throughout the study there was a reduction in LDL-C levels from 135.6 mg /dL at baseline, 107.4 mg /dL in the 2nd visit, 97.3 mg /dL in the 3rd visit, up to 90.7 mg /dL at the final visit (p &lt;0.0001) The increase in HDL-C from baseline (50.9 mg /dL) and final (53.6 mg /dL) was also significant (p = 0.013). Conclusions: The reassessment and intensification of treatment in patients at high cardiovascular risk treated in primary care, applying the indications of the guides, achieves the OT in more than three quarters of the previously uncontrolled within half a year. These results should encourage us to overcome the therapeutic inertia in the control of CVD by early and energetic performance against hypercholesterolemia.Introducción: La hipercolesterolemia es uno de los principales factores de riesgo modificables de la enfermedad cardiovascular (ECV). Su reducción disminuye la morbimortalidad por cardiopatía isquémica y ECV en general, en prevención primaria y en prevención secundaria especialmente. Objetivo: Comprobar si una práctica clínica protocolizada e intensiva permite vencer la inercia y alcanzar el objetivo terapéutico (OT) de c-LDL < 100 mg/dL en pacientes de alto riesgo asistidos en Atención Primaria (AP) de nuestro país. Metodología: Estudio epidemiológico, prospectivo, multicentrico, realizado en Centros de AP de diferentes CC.AA. Mediante muestreo consecutivo se incluyeron 310 pacientes de alto riesgo cardiovascular (diabéticos o con ECV establecida), tratados previamente con estatinas, que no alcanzaban el OT de c-LDL. Resultados: Los sujetos del estudio tenían una edad media de 65,2 años, de los que el 60,32% eran varones. El 41,64% presentaba un EVC previo, infarto agudo de miocardio (20,33%), angina (16,07%), ictus/AIT (9,19%), artropatía (5,25%), diabetes (70,87%), hipertensión (71,01%), y obesidad abdominal (69,62%). El 43,57% (IC95%: 37,21; 50,08) de los pacientes que realizaron la 2a visita (241) consiguieron el OT. El 62,50% (IC95%: 55,68; 68,98) de los que realizaron la 3a (216) consiguieron el OT. Finalmente, el 77,56% (IC95%: 72,13; 83,08) de los pacientes que realizaron la última visita (205) consiguieron el OT. A lo largo del estudio hubo una reducción de los niveles de c-LDL desde los 135,6 mg/ dL en la visita basal, 107,4 mg/dL en la 2a visita, 97,3 mg/ dL en la 3a visita, hasta los 90,7 mg/dL en la visita final (p < 0,0001) El incremento de c-HDL entre la visita basal (50,9 mg/dL) y la final (53,6 mg/dL) también fue significativo (p = 0,013). Conclusiones: La reevaluación e intensificación del tratamiento en pacientes de alto riesgo cardiovascular atendidos en Atención Primaria, aplicando las indicaciones de las guías, permite alcanzar el OT en más de las tres cuartas partes de los previamente no controlados en el plazo de medio año. Estos resultados nos deben estimular a superar la inercia terapéutica en el control de la ECV mediante una actuación precoz y enérgica ante la hipercolesterolemi

Serum amyloid a1/toll-like receptor-4 Axis, an important link between inflammation and outcome of TBI patients

Traumatic brain injury (TBI) is one of the leading causes of mortality and disability world-wide without any validated biomarker or set of biomarkers to help the diagnosis and evaluation of the evolution/prognosis of TBI patients. To achieve this aim, a deeper knowledge of the biochemical and pathophysiological processes triggered after the trauma is essential. Here, we identified the serum amyloid A1 protein-Toll-like receptor 4 (SAA1-TLR4) axis as an important link between inflammation and the outcome of TBI patients. Using serum and mRNA from white blood cells (WBC) of TBI patients, we found a positive correlation between serum SAA1 levels and injury severity, as well as with the 6-month outcome of TBI patients. SAA1 levels also correlate with the presence of TLR4 mRNA in WBC. In vitro, we found that SAA1 contributes to inflammation via TLR4 activation that releases inflammatory cytokines, which in turn increases SAA1 levels, establishing a positive proinflammatory loop. In vivo, post-TBI treatment with the TLR4-antagonist TAK242 reduces SAA1 levels, improves neurobehavioral outcome, and prevents blood–brain barrier disruption. Our data support further evaluation of (i) post-TBI treatment in the presence of TLR4 inhibition for limiting TBI-induced damage and (ii) SAA1-TLR4 as a biomarker of injury progression in TBI patientsThis work was supported by grants from Fundación Mutua Madrileña and Fondo de Investigaciones Sanitarias (FIS) (ISCIII/FEDER) (Programa Miguel Servet CP14/00008; CPII19/00005; PI16/00735; PI19/00082) to JE, RYC2019-026870-I to JMR and PI18/01387 to A

Performability Analysis of an Adaptive-Rate Video-Streaming Service in End-to-End QoS Scenarios

Abstract. Nowadays, dynamic service management frameworks are proposed to ensure end-to-end QoS. To achieve this goal, it is necessary to manage Ser-vice Level Agreements (SLAs), which specify quality parameters of the services operation such as availability and performance. This work is focused on the eval-uation of Video-on-Demand (VoD) services in end-to-end QoS scenarios. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of an adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system. In this way, new design options can be proposed and be easily evalu-ated. To compute performability measures of the MRC model, the randomization method is employed. Predicted model results fit well to the ones taken from a real video-streaming testbed.

Self-Similar Traffic Generation Using A Fractional Arima Model. Application To The Vbr Mpeg Video Traffic

Recent studies and traffic measurements have shown that variable bit rate (VBR) video traffic, as well as local area networks (LAN) traffic, exhibits long range dependence (LRD). When this kind of traffic is transmitted over ATM networks, the LRD property implies a bigger necessity in term of buffer allocation and channel capacity. In this paper, a new fractional ARIMA model for VBR MPEG video traffic at frame level is presented. The fractional integrative component of the model is based on a process called &quot;fractional differencing&quot;. The model has been obtained from three very long sequences. It has been used to synthesize artificial traffic, which presents the desired LRD. Keywords: Self-similar traffic, VBR MPEG video traffic, Fractional ARIMA models. 1. Introduction Local area networks (LAN) and variable bit rate (VBR) video traffics exhibits long range dependence (LRD) in their autocorrelation function [1][2][3]. This kind of traffic has been called selfsimilar traffic, because i..

Predictive shaping for VBR MPEG video traffic transmission over ATM networks

The use of smoothing techniques to remove the periodic fluctuations of the bit rate generated by the codification modes of the MPEG algorithm is very suitable in video transmission. In this way, the multiplexing gain is maximized and the resource allocation is reduced in ATM Networks. The traffic smoothing can be achieved storing the cells in a buffer. This buffer is allocated between the coder and the user-interface. To reduce the delay introduced in the storage process a new technique to forecast the VBR MPEG traffic is presented. This technique is based on the characterization of bits per frame generated by the MPEG coder as an ARIMA process. In this study the invariance of the ARIMA coefficients is verified for all coded sequences used. In addition, these coefficients are invariant also in front of the changes of the selected image quality in the coder. This characterization allows to propose a new traffic shaper scheme when forecast techniques are applied. Moreover, numerical resu..