Joint scheduling of communication and computation resources in multiuser wireless application offloading

We consider a system where multiple users are connected to a small cell base station enhanced with computational capabilities. Instead of doing the computation locally at the handset, the users offload the computation of full applications or pieces of code to the small cell base station. In this scenario, this paper provides a strategy to allocate the uplink, downlink, and remote computational resources. The goal is to improve the quality of experience of the users, while achieving energy savings with respect to the case in which the applications run locally at the mobile terminals. More specifically, we focus on minimizing a cost function that depends on the latencies experienced by the users and provide an algorithm to minimize the latency experienced by the worst case user, under a target energy saving constraint per user.Postprint (author’s final draft

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Multiuser scheduling strategies for wireless application offloading

Development of new scheduling strategies for wireless application offloadingSmartphones are no longer used only for voice communication; instead, they are used for web surfing, GPS navigation, acquiring and watching videos and photos, gaming, and many other purposes. As consequence, these systems consume more power and shorten the battery life. Even though the battery technology has been continuously improving, it has not been able to keep up with the rapid growth of power consumption of these mobile devices. As a result, energy consumption has become a primary constraint for battery-powered mobile systems. On the other hand, mobiles terminals (MTs) have limited computation resources and thus there is an increasing gap between the demand for complex applications and the availability of the required resources for executing such applications in mobile devices. Cloud computing is a flexible and costeffective concept that allows MTs to have access to larger computational resources than those available in typical terminals. These computational resources, such as processing, memory and storage, are located in remote devices (i.e. servers) and the terminals access them via mobile wireless channels. Cloud computing may extend the battery life by migrating the energy-intensive parts of the computation to the remote server. On the other hand, small cells deployments can be seen as an opportunity to offer low-cost solutions for cloud computing services if the small cells are equipped with some enhanced computational and storage capabilities. In a multiuser scenario, the available resources must be shared among the different users, including the radio resources required for the communication between the MT and the small cell in the uplink and downlink, and the processing resources located at the remote processor. The main objective of this master thesis is to develop new scheduling strategies for this scenario in order to improve the quality of service (QoS) perceived by the different users in terms of delay, while achieving a target energy saving. In this sense, we have considered two different approaches: three decoupled schedulers, each one managing the uplink, processing and downlink resources independently, and a single scheduler which allocates jointly the communication and computation resources

Sistema de gestión de interferencias para redes LTE-A con despliegue de femtoceldas

Es proposa un sistema de gestió d'interferències per a xarxes LTE amb femtocel·les, basat en un nou algoritme de detecció que s'integra en la capa física dels terminals mòbils.[ANGLÈS] Femtocells are low-power cellular base stations designed to serve homes, businesses or other scenarios with low coverage needs. These stations reuse the same frequency bands assigned to the outer 4G network in order to increase the transmission rate per area unit. This technology significantly improves the capacity and efficiency of 4G networks, since a greater number of users can potentially access the same set of radio resources. To ensure peaceful coexistence between conventional femtocells and 4G networks, it is necessary to develop new techniques for dynamic resource and interference management to ensure a certain level of quality of service (QoS). This project proposes a new interference detection mechanism, which would be the key to develop new interference management systems. Specifically, the project focuses on minimizing the impact of femtocells on primary transmissions (between macrocells and terminals under its coverage). The proposed mechanism is incorporated into the physical layer (PHY) of mobile terminals, allowing the network to collect real-time information about the terminals which are suffering interferences. With this information, the network can inform the nearby femtocells to change their transmission strategy, ceasing to transmit in the bands where they are interfering.[CASTELLÀ] Las femtoceldas son estaciones base de telefonía móvil de baja potencia, pensadas para dar servicio a domicilios particulares, negocios u otros escenarios con necesidades de cobertura reducidas. Estas estaciones reutilizan las mismas bandas frecuenciales asignadas a las redes 4G exteriores con el objetivo de incrementar la velocidad de transmisión por unidad de área. Esta tecnología mejora significativamente la capacidad y la eficiencia de las redes 4G, ya que un mayor número de usuarios pueden acceder potencialmente al mismo conjunto de recursos radio. Para garantizar la convivencia entre femtoceldas y redes 4G convencionales, es necesario el desarrollo de nuevas técnicas de gestión dinámica de recursos e interferencias que garanticen un determinado nivel de calidad de servicio (QoS). En este proyecto se propone un nuevo mecanismo de detección de señal interferente, que sería la pieza clave para desarrollar nuevos sistemas de gestión de interferencias. Concretamente, el proyecto se centra en minimizar el impacto de las femtoceldas sobre las transmisiones primarias (entre macroceldas y terminales que se encuentran bajo su cobertura). El mecanismo propuesto se incorpora en la capa física (PHY) de los terminales móviles, permitiendo a la red recopilar información en tiempo real sobre los terminales que están sufriendo interferencias en recepción. Con esta información, la red puede informar a las femtoceldas próximas para que cambien su estrategia de transmisión, dejando de transmitir por las bandas donde están interfiriendo.[CATALÀ] Les femtocel·les són estacions base de telefonia mòbil de baixa potència, pensades per donar servei a domicilis particulars, negocis o altres escenaris amb necessitats de cobertura reduïdes. Aquestes estacions reutilitzen les mateixes bandes freqüencials assignades a les xarxes 4G exteriors amb l'objectiu d'incrementar la velocitat de transmissió per unitat d'àrea. Aquesta tecnologia millora significativament la capacitat i l'eficiència de les xarxes 4G, ja que un major número d'usuaris poden accedir potencialment al mateix conjunt de recursos ràdio. Per garantir la convivència entre femtocel·les i xarxes 4G convencionals, és necessari el desenvolupament de noves tècniques de gestió dinàmica de recursos i interferències que garanteixin un determinat nivell de qualitat de servei (QoS). En aquest projecte es proposa un nou mecanisme de detecció de senyal interferent, que seria la peça clau per desenvolupar nous sistemes de gestió d'interferències. Concretament, el projecte se centra en minimitzar l'impacte de les femtocel·les sobre les transmissions primàries (entre macrocel·les i terminals que es troben sota la seva cobertura). El mecanisme proposat s'incorpora en la capa física (PHY) dels terminals mòbils, permetent a la xarxa recopilar informació en temps real sobre els terminals que estan patint interferències en recepció. Amb aquesta informació, la xarxa pot informar a les femtocel·les properes per a que canviïn la seva estratègia de transmissió, deixant de transmetre per les bandes on estan interferint

Multiuser scheduling strategies for wireless application offloading

Development of new scheduling strategies for wireless application offloadingSmartphones are no longer used only for voice communication; instead, they are used for web surfing, GPS navigation, acquiring and watching videos and photos, gaming, and many other purposes. As consequence, these systems consume more power and shorten the battery life. Even though the battery technology has been continuously improving, it has not been able to keep up with the rapid growth of power consumption of these mobile devices. As a result, energy consumption has become a primary constraint for battery-powered mobile systems. On the other hand, mobiles terminals (MTs) have limited computation resources and thus there is an increasing gap between the demand for complex applications and the availability of the required resources for executing such applications in mobile devices. Cloud computing is a flexible and costeffective concept that allows MTs to have access to larger computational resources than those available in typical terminals. These computational resources, such as processing, memory and storage, are located in remote devices (i.e. servers) and the terminals access them via mobile wireless channels. Cloud computing may extend the battery life by migrating the energy-intensive parts of the computation to the remote server. On the other hand, small cells deployments can be seen as an opportunity to offer low-cost solutions for cloud computing services if the small cells are equipped with some enhanced computational and storage capabilities. In a multiuser scenario, the available resources must be shared among the different users, including the radio resources required for the communication between the MT and the small cell in the uplink and downlink, and the processing resources located at the remote processor. The main objective of this master thesis is to develop new scheduling strategies for this scenario in order to improve the quality of service (QoS) perceived by the different users in terms of delay, while achieving a target energy saving. In this sense, we have considered two different approaches: three decoupled schedulers, each one managing the uplink, processing and downlink resources independently, and a single scheduler which allocates jointly the communication and computation resources

Multiplexació de senyals DVB: anàlisi i millora del software mplex13818

Aquest TFC tracta sobre la multiplexació de senyals de vídeo i àudio MPEG-2, estàndard en què es basen la major part d'aplicacions de difusió i emmagatzematge de vídeo digital. Concretament, se centra en els Transport Streams, adequats per a difondre continguts audiovisuals en format digital a través de multitud de plataformes com poden ser la televisió digital terrestre (TDT), la televisió per satèl·lit i per cable, i la difusió de continguts audiovisuals a través d'Internet, entre altres. L'objectiu final del treball era l'obtenció d'una peça de software de codi obert que permetés generar aquest tipus de fluxos de transport. Per aconseguir-ho, s'ha partit d'un programa ja existent, l'Mplex 13818, del qual se n'ha modificat el codi per millorar les seves prestacions, ja que les proves inicials van descobrir deficiències en la seva implementació que n'impossibilitaven l'ús. Després de realitzar una explicació teòrica sobre els estàndards que intervenen en la generació dels fluxos de transport, una part important del treball s'ha centrat en l'anàlisi del Mplex 13818, amb la finalitat de descriure l'algoritme de multiplexació que utilitza i buscar els problemes d'implementació que s'havien de tractar. Concretament s'han detectat dos aspectes a corregir, relacionats amb el sistema de temporització, que impossibilitaven la correcta reproducció dels streams generats amb Mplex. Per avaluar el resultat de les millores proposades s'han realitzat proves a partir de captures de diferents múltiplex, combinant-les tal d'obtenir nous fluxos de transport barrejant programes de les fluxos originals. Els resultats han estat satisfactoris, aconseguint que els Transport Streams generats amb Mplex compleixin l'estàndard ISO 13818-1 (capa de sistema MPEG-2)