70 research outputs found
MODELLING AND OPTIMIZATION OF COMPUTER NETWORK TRAFFIC CONTROLLERS
During the past years, there has been increasing interest in the design and development of network traffic controllers capable of ensuring the QoS requirements of a wide range of applications. In this paper, we construct a dynamic model for the token-bucket algorithm: a traffic controller widely used in various QoS-aware protocol architectures. Based on our previous work, we use a system approach to develop a formal model of the traffic controller. This model serves as a basis to formally specify and evaluate the operation of the token-bucket algorithm. Then we develop an optimization algorithm based on a dynamic programming and genetic algorithm approach. We conduct an extensive campaign of numerical experiments allowing us to gain insight on the operation of the controller and evaluate the benefits of using a genetic algorithm approach to speed up the optimization process. Our results show that the use of the genetic algorithm proves particularly useful in reducing the computation time required to optimize the operation of a system consisting of multiple token-bucket-regulated sources. 1
Very low complexity mpeg-2 to h.264 transcoding using machine learning
ABSTRACT This paper presents a novel macroblock mode decision algorithm for inter-frame prediction based on machine learning techniques to be used as part of a very low complexity MPEG-2 to H.264 video transcoder. Since coding mode decisions take up the most resources in video transcoding, a fast macro block (MB) mode estimation would lead to reduced complexity. The proposed approach is based on the hypothesis that MB coding mode decisions in H.264 video have a correlation with the distribution of the motion compensated residual in MPEG-2 video. We use machine learning tools to exploit the correlation and derive decision trees to classify the incoming MPEG-2 MBs into one of the 11 coding modes in H.264. The proposed approach reduces the H.264 MB mode computation process into a decision tree lookup with very low complexity. The proposed transcoder is compared with a reference transcoder comprised of a MPEG-2 decoder and an H.264 encoder. Our results show that the proposed transcoder reduces the H.264 encoding time by over 95% with negligible loss in quality and bitrate
Validez de constructo de un instrumento de enfermería para evaluar adherencia al tratamiento antihipertensivo
Introduction: In nursing, art and science of caring, is important to the use of the nursing process using a standardized language. Therefore, having valid nursing results labels, applied pre and pos intervention, allows the professional to evaluate and demonstrate the impact of such interventions. Especially in the management of common problems in the adult population such as high blood pressure. Objective: Determine the construct validity of the result of nursing "therapeutic conduct: illness or injury" (classification of result NOC 1609) to measure adherence to treatment. Methodology: Study of evaluation of diagnostic technologies nested in cross-sectional population study, carried out in the year 2010. 166 People with hypertension of stratum two and three of Bucaramanga were assessed. The construct validity of the result of nursing "therapeutic conduct: illness or injury" (NOC 1609) to measure adherence to treatment both pharmacological and non-pharmacological was determine using Rasch analysis. Results: The nursing outcome is one-dimensional, it assesses the construct ‘adherence'; the five original answers options regrouped in three, to achieve adequate differentiation in the options of answers, thus reaching a good reliability (0.99) and separation of the items (8.90); In addition, data adjusted to the Rasch model (values infit and outfit: > 0.6 and <1.4) and there was no differential behavior by sex (P> 0.05). Conclusion: The result of nursing evaluated is an appropriate instrument to measure the adhesion because it has construct validity.RESUMEN Introducción: En enfermería, arte y la ciencia de cuidar, es importante el uso del proceso de enfermería a través de un lenguaje estandarizado. Por lo tanto, contar con etiquetas de resultados de enfermería validas, aplicadas pre y pos intervención, permite al profesional evaluar y demostrar el impacto de dichas intervenciones. Especialmente, en el manejo de problemas frecuentes en la población adulta como lo es la hipertensión arterial.Objetivo: Determinar la validez de constructo del resultado de enfermería “conducta terapéutica: enfermedad o lesión” (clasificación de resultado CRE 1609) para medir adherencia al tratamiento. Metodología: Se realizó un estudio de evaluación de tecnologías diagnósticas anidado en un estudio de corte transversal poblacional, realizado en el año 2010. Se evaluaron 166 personas con hipertensión arterial de estrato dos y tres de Bucaramanga. Mediante el análisis Rasch, se determinó la validez de constructo del resultado de enfermería “conducta terapéutica: enfermedad o lesión” (CRE 1609) para medir adherencia al tratamiento, tanto farmacológico como no farmacológico.Resultados: el resultado de enfermería es unidimensional, evalúa el constructo “adherencia”; las cinco opciones de respuestas originales se reagruparon en tres, para lograr una adecuada diferenciación en las opciones de respuestas, alcanzando así una buena confiabilidad (0.99) y separación de los ítems (8.90); además, los datos ajustaron al modelo Rasch (valores infit y outfit: >0.6 y <1.4) y los ítems no presentaron comportamiento diferencial por sexo (valor de p >0,05).Conclusión: el resultado de enfermería evaluado es un instrumento apropiado para medir la adherencia pues cuenta con validez de constructo
IoT protocols, architectures, and applications
The proliferation of embedded systems, wireless technologies, and Internet protocols have made it possible for the Internet-of-things (IoT) to bridge the gap between the physical and the virtual world and thereby enabling monitoring and control of the physical environment by data processing systems. IoT refers to the inter-networking of everyday objects that are equipped with sensing, computing, and communication capabilities. These networks can collaborate to autonomously solve a variety of tasks. Due to the very diverse set of applications and application requirements, there is no single communication technology that is able to provide cost-effective and close to optimal performance in all scenarios. In this chapter, we report on research carried out on a selected number of IoT topics: low-power wide-area networks, in particular, LoRa and narrow-band IoT (NB-IoT); IP version 6 over IEEE 802.15.4 time-slotted channel hopping (6TiSCH); vehicular antenna design, integration, and processing; security aspects for vehicular networks; energy efficiency and harvesting for IoT systems; and software-defined networking/network functions virtualization for (SDN/NFV) IoT
Dementia in Latin America : paving the way towards a regional action plan
Regional challenges faced by Latin American and Caribbean countries (LACs) to fight dementia, such as heterogeneity, diversity, political instabilities, and socioeconomic disparities, can be addressed more effectively grounded in a collaborative setting based on the open exchange of knowledge. In this work, the Latin American and Caribbean Consortium on Dementia (LAC-CD) proposes an agenda for integration to deliver a Knowledge to Action Framework (KtAF). First, we summarize evidence-based strategies (epidemiology, genetics, biomarkers, clinical trials, nonpharmacological interventions, networking and translational research) and align them to current global strategies to translate regional knowledge into actions with transformative power. Then, by characterizing genetic isolates, admixture in populations, environmental factors, and barriers to effective interventions and mapping these to the above challenges, we provide the basic mosaics of knowledge that will pave the way towards a KtAF. We describe strategies supporting the knowledge creation stage that underpins the translational impact of KtAF
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Developpement et evaluation de performances du protocole de transport de l'ISO pour reseaux locaux
SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
04 Sistemas de Comunicaciones Multimedia para Aplicaciones Médicas
En los últimos años, el empleo de redes de computadores ha supuesto una auténtica revolución, modificando hábitos y agilizando enormemente muchas tareas. En entornos industriales y comerciales, cada vez es más importante disponer de una buena infraestructura de redes, siendo soporte de muchas aplicaciones impensables hace unas décadas. Todo ello lleva asociado un empleo cada vez más masivo de las redes de computadores, lo que implica que se le requieran mayores capacidades, mejores prestaciones y una elevada fiabilidad.
En la actualidad, con el desarrollo de nuevas tecnologías de conmutación y transmisión de datos, y la utilización de soportes de transmisión eficientes, asistimos a una nueva generación de redes que se caracterizan por ofrecer altas prestaciones y soportar distintos tipos de servicios, lo que permite plantearse de forma sensata la implementación de nuevos servicios y aplicaciones. En el ámbito de las redes locales, cada vez son más eficientes los sistemas distribuidos basados en redes locales de altas prestaciones, o redes de estaciones de trabajo, que en algunos casos pueden ofrecer rendimientos muy elevados con un coste muy inferior al de un multicomputador. En el ámbito de las redes de área extensa, asistimos al desarrollo de tecnologías que permiten integrar distintos tipos de tráfico. Como consecuencia de la implantación de tecnologías multimedia, es fundamental disponer de ciertas calidades de servicio, lo que obliga a la red a tratar de forma diferenciada los distintos tipos de tráfico, siendo éste uno de los puntos clave en el diseño actual de tecnologías de redes. Como consecuencia de la existencia de redes de altas prestaciones, comienzan a desarrollarse nuevas aplicaciones que una vez implantadas, no harán sino requerir mayores prestaciones de la red, lo que sin duda traerá asociados nuevos desarrollos y nuevas tecnologías. En este libro se muestran las tendencias actuales en el campo de las redes de altas prestaciones
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