Search results for "Location"
showing 10 items of 1480 documents
On the Performance of Channel Assembling and Fragmentation in Cognitive Radio Networks
2014
[EN] Flexible channel allocation may be applied to multi-channel cognitive radio networks (CRNs) through either channel assembling (CA) or channel fragmentation (CF). While CA allows one secondary user (SU) occupy multiple channels when primary users (PUs) are absent, CF provides finer granularity for channel occupancy by allocating a portion of one channel to an SU flow. In this paper, we investigate the impact of CF together with CA for SU flows by proposing a channel access strategy which activates both CF and CA and correspondingly evaluating its performance. In addition, we also consider a novel scenario where CA is enabled for PU flows. The performance evaluation is conducted based on…
Model and optimal Call Admission Policy in Cellular Mobile Networks
2000
For current cellular networks, two important Quality of Service (QoS) measures are the fractions of new and handoff calls that are blocked due to unavailability of channels. Based on these QoS measures, we propose a queuing network model with impatient users for handoff and new calls in cellular mobile networks. The number of simultaneous calls, that can be supported, is modeled by C identical servers with exponentially distributed session duration for each one of them. Priority is given to handoffs over new calls. We use for that a Guard Channel policy that reserves a set of CH channels for handoff calls, new calls being served at their arrival if there are more than CH available channels.…
<title>Statistical bandwidth allocation for multiservice networks</title>
2002
Multiservice networks will carry di erent kinds of applications in the near future. Bandwidth requirements change rapidly, and the network resource management will play an important role to guarantee the use of the limited resources in the most eAEcient way. We approach the channel capacity allocation problem by developing an SLA (Service Level Agreement) based channel allocation method. In our model, the channel may be wired or wireless, so this method can be adapted in multi-technique networks. The algorithm allocates resources to several di erent service classes via several di erent capacity routes. Service provider perfroms optimization by allocating data rate in such a way that the sat…
The Community Structure of the Global Corporate Network
2013
We investigate the community structure of the global ownership network of transnational corporations. We find a pronounced organization in communities that cannot be explained by randomness. Despite the global character of this network, communities reflect first of all the geographical location of firms, while the industrial sector plays only a marginal role. We also analyze the network in which the nodes are the communities and the links are obtained by aggregating the links among firms belonging to pairs of communities. We analyze the network centrality of the top 50 communities and we provide the first quantitative assessment of the financial sector role in connecting the global economy.
Inhibitory effects of N-acetylcysteine on the functional responses of human eosinophils in vitro
2007
Background Oxidative stress appears to be relevant in the pathogenesis of inflammation in allergic diseases like bronchial asthma. Eosinophils are oxidant-sensitive cells considered as key effectors in allergic inflammation. Objective The aim of this work was to study the effects of the clinically used antioxidant N-acetyl-L-cysteine (NAC) on the functional responses of human-isolated eosinophils. Methods Human eosinophils were purified from the blood of healthy donors by a magnetic bead separation system. The effects of NAC were investigated on the generation of reactive oxygen species (chemiluminescence and flow cytometry), Ca2+ signal (fluorimetry), intracellular glutathione (GSH; flow c…
Yeast β-glucans and microalgal extracts modulate the immune response and gut microbiome in Senegalese sole (Solea senegalensis)
2019
One bottleneck to sustainability of fish aquaculture is the control of infectious diseases. Current trends include the preventive application of immunostimulants and prebiotics such as polysaccharides. The present study investigated how yeast β-glucan (Y), microalgal polysaccharide-enriched extracts (MAe) and whole Phaeodactylum tricornutum cells (MA) modulated the gut microbiome and stimulated the immune system in Senegalese sole (Solea senegalensis) when administered by oral intubation. Blood, intestine and spleen samples were taken at 3 h, 24 h, 48 h and 7 days after treatment. The short-term response (within 48 h after treatment) consisted of up-regulation of il1b and irf7 expression in…
Macroeconomic determinants of Peruvian migration flows
2020
The objective of this paper is to determine the variables associated with the weight that Peruvian immigration has in the total immigration in Chile for the period 2005-2014. The initial hypothesis is that the Peruvian migratory flow has a social and economic component. The results showed that an increase in the Human Development Index (HDI) in favor of Chile increases the migratory flow. On the other hand, a larger education budget in favor of Chile decreases the migratory flow of Peruvian citizens.
Scope-Oriented Thermoeconomic analysis of energy systems. Part I: Looking for a non-postulated cost accounting for the dissipative devices of a vapou…
2010
Abstract The authors of the main thermoeconomic methodologies developed in the last two decades have recently focused their efforts on the analysis of dissipative devices, i.e. those components whose productive purpose is neither intuitive nor easy to define. Coherent and unanimously accepted cost structures have been identified for dissipative components, while ambiguities still exist as concerns the cost allocation principles to be adopted. Being this aspect evidently cost-influencing, accurate analyses focused on the subjectivity of results are needed. This paper is structured in two parts. In the Part I an in-depth study of some critical issues arising from the thermoeconomic analysis o…
Dominance and leadership in research activities: Collaboration between countries of differing human development is reflected through authorship order…
2017
Introduction Scientific collaboration is an important mechanism that enables the integration of the least developed countries into research activities. In the present study, we use the order of author signatures and addresses for correspondence in scientific publications as variables to analyze the interactions between countries of very high (VHHD), high (HHD), medium (MHD), and low human development (LHD). Methodology We identified all documents published between 2011 and 2015 in journals included in the Science Citation Index-Expanded categories’ of Tropical Medicine, Infectious Diseases, Parasitology, and Pediatrics. We then classified the countries participating in the publications acco…
Transnationalization through country-of-origin clusters: drivers and challenges in China
2017
La internacionalización hoy en día no es una opción, sino una realidad. Este nuevo entorno global repercute claramente en las organizaciones, cuyas estructuras tienen que afrontar nuevos retos sociales, culturales, competitivos e institucionales. En un entorno de estas características la internacionalización en colaboración aparece como una oportunidad y/o necesidad apremiante para múltiples empresas. Las empresas españolas llevan tiempo inmersas en este proceso de globalización que desde 2007 se ve dominado por la peor crisis financiera y económica de las últimas décadas. Sin embargo, la falta de experiencia internacional les plantea la reflexión de afrontar el reto de la internacionalizac…