774 resultados para peer-to-peer (P2P) computing


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Process variations are a major bottleneck for digital CMOS integrated circuits manufacturability and yield. That iswhy regular techniques with different degrees of regularity are emerging as possible solutions. Our proposal is a new regular layout design technique called Via-Configurable Transistors Array (VCTA) that pushes to the limit circuit layout regularity for devices and interconnects in order to maximize regularity benefits. VCTA is predicted to perform worse than the Standard Cell approach designs for a certain technology node but it will allow the use of a future technology on an earlier time. Ourobjective is to optimize VCTA for it to be comparable to the Standard Cell design in an older technology. Simulations for the first unoptimized version of our VCTA of delay and energy consumption for a Full Adder circuit in the 90 nm technology node are presented and also the extrapolation for Carry-RippleAdders from 4 bits to 64 bits.

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This paper presents a probabilistic approach to model the problem of power supply voltage fluctuations. Error probability calculations are shown for some 90-nm technology digital circuits.The analysis here considered gives the timing violation error probability as a new design quality factor in front of conventional techniques that assume the full perfection of the circuit. The evaluation of the error bound can be useful for new design paradigms where retry and self-recoveringtechniques are being applied to the design of high performance processors. The method here described allows to evaluate the performance of these techniques by means of calculating the expected error probability in terms of power supply distribution quality.

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This paper analyzes the asymptotic performance of maximum likelihood (ML) channel estimation algorithms in wideband code division multiple access (WCDMA) scenarios. We concentrate on systems with periodic spreading sequences (period larger than or equal to the symbol span) where the transmitted signal contains a code division multiplexed pilot for channel estimation purposes. First, the asymptotic covariances of the training-only, semi-blind conditional maximum likelihood (CML) and semi-blind Gaussian maximum likelihood (GML) channelestimators are derived. Then, these formulas are further simplified assuming randomized spreading and training sequences under the approximation of high spreading factors and high number of codes. The results provide a useful tool to describe the performance of the channel estimators as a function of basicsystem parameters such as number of codes, spreading factors, or traffic to training power ratio.

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The Wigner higher order moment spectra (WHOS)are defined as extensions of the Wigner-Ville distribution (WD)to higher order moment spectra domains. A general class oftime-frequency higher order moment spectra is also defined interms of arbitrary higher order moments of the signal as generalizations of the Cohen’s general class of time-frequency representations. The properties of the general class of time-frequency higher order moment spectra can be related to theproperties of WHOS which are, in fact, extensions of the properties of the WD. Discrete time and frequency Wigner higherorder moment spectra (DTF-WHOS) distributions are introduced for signal processing applications and are shown to beimplemented with two FFT-based algorithms. One applicationis presented where the Wigner bispectrum (WB), which is aWHOS in the third-order moment domain, is utilized for thedetection of transient signals embedded in noise. The WB iscompared with the WD in terms of simulation examples andanalysis of real sonar data. It is shown that better detectionschemes can be derived, in low signal-to-noise ratio, when theWB is applied.

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INDISIM-YEAST, an individual-based simulator, models the evolution of a yeast population by settingup rules of behaviour for each individual cell according to their own biological rules and characteristics. Ittakes into account the uptake, metabolism, budding reproduction and viability of the yeast cells, over aperiod of time in the bulk of a liquid medium, occupying a three dimensional closed spatial grid with twokinds of particles (glucose and ethanol). Each microorganism is characterized by its biomass, genealogicalage, states in the budding cellular reproduction cycle and position in the space among others. Simulationsare carried out for population properties (global properties), as well as for those properties that pertain toindividual yeast cells (microscopic properties). The results of the simulations are in good qualitativeagreement with established experimental trends.

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Peer reviewed

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This study examines how firms interpret new, potentially disruptive technologies in their own strategic context. The work presents a cross-case analysis of four potentially disruptive technologies or technical operating models: Bluetooth, WLAN, Grid computing and Mobile Peer-to-peer paradigm. The technologies were investigated from the perspective of three mobile operators, a device manufacturer and a software company in the ICT industry. The theoretical background for the study consists of the resource-based view of the firm with dynamic perspective, the theories on the nature of technology and innovations, and the concept of business model. The literature review builds up a propositional framework for estimating the amount of radical change in the companies' business model with two middle variables, the disruptiveness potential of a new technology, and the strategic importance of a new technology to a firm. The data was gathered in group discussion sessions in each company. The results of each case analysis were brought together to evaluate, how firms interpret the potential disruptiveness in terms of changes in product characteristics and added value, technology and market uncertainty, changes in product-market positions, possible competence disruption and changes in value network positions. The results indicate that the perceived disruptiveness in terms ofproduct characteristics does not necessarily translate into strategic importance. In addition, firms did not see the new technologies as a threat in terms of potential competence disruption.

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Rare diseases are typically chronic medical conditions of genetic etiology characterized by low prevalence and high complexity. Patients living with rare diseases face numerous physical, psychosocial and economic challenges that place them in the realm of health disparities. Congenital hypogonadotropic hypogonadism (CHH) is a rare endocrine disorder characterized by absent puberty and infertility. Little is known about the psychosocial impact of CHH on patients or their adherence to available treatments. This project aimed to examine the relationship between illness perceptions, depressive symptoms and adherence to treatment in men with CHH using the nursing-sensitive Health Promotion Model (HPM). A community based participatory research (CBPR) framework was employed as a model for empowering patients and overcoming health inequities. The study design used a sequential, explanatory mixed-methods approach. To reach dispersed CHH men, we used web-based recruitment and data collection (online survey). Subsequently, three patient focus groups were conducted to provide explanatory insights into the online survey (i.e. barriers to adherence, challenges of CHH, and coping/support) The online survey (n=101) revealed that CHH men struggle with adherence and often have long gaps in care (40% >1 year). They experience negative psychosocial consequences because of CHH and exhibit significantly increased rates of depression (p<0.001). Focus group participants (n=26) identified healthcare system, interpersonal, and personal factors as barriers to adherence. Further, CHH impacts quality of life and impedes psychosexual development in these men. The CHH men are active internet users who rely on the web forcrowdsourcing solutions and peer-to-peer support. Moreover, they are receptive to web-based interventions to address unmet health needs. This thesis contributes to nursing knowledge in several ways. First, it demonstrates the utility of the HPM as a valuable theoretical construct for understanding medication adherence and for assessing rare disease patients. Second, these data identify a range of unmet health needs that are targets for patient-centered interventions. Third, leveraging technology (high-tech) effectively extended the reach of nursing care while the CBPR approach and focus groups (high-touch) served as concurrent nursing interventions facilitating patient empowerment in overcoming health disparities. Last, these findings hold promise for developing e-health interventions to bridge identified shortfalls in care and activating patients for enhanced self- care and wellness -- Les maladies rares sont généralement de maladies chroniques d'étiologie génétique caractérisées par une faible prévalence et une haute complexité de traitement. Les patients atteints de maladies rares sont confrontés à de nombreux défis physiques, psychosociaux et économiques qui les placent dans une posture de disparité et d'inégalités en santé. L'hypogonadisme hypogonadotrope congénital (CHH) est un trouble endocrinien rare caractérisé par l'absence de puberté et l'infertilité. On sait peu de choses sur l'impact psychosocial du CHH sur les patients ou leur adhésion aux traitements disponibles. Ce projet vise à examiner la relation entre la perception de la maladie, les symptômes dépressifs et l'observance du traitement chez les hommes souffrant de CHH. Cette étude est modélisée à l'aide du modèle de la Promotion de la santé de Pender (HPM). Le cadre de l'approche communautaire de recherche participative (CBPR) a aussi été utilisé. La conception de l'étude a reposé sur une approche mixte séquentielle. Pour atteindre les hommes souffrant de CHH, un recrutement et une collecte de données ont été organisées électroniquement. Par la suite, trois groupes de discussion ont été menées avec des patients experts impliqués au sein d'organisations reliés aux maladies rares. Ils ont été invités à discuter certains éléments additionnels dont, les obstacles à l'adhésion au traitement, les défis généraux de vivre avec un CHH, et l'adaptation à la maladie en tenant compte du soutien disponible. Le sondage en ligne (n = 101) a révélé que les hommes souffrant de CHH ont souvent de longues périodes en rupture de soins (40% > 1 an). Ils vivent des conséquences psychosociales négatives en raison du CHH et présentent une augmentation significative des taux de dépression (p <0,001). Les participants aux groupes de discussion (n = 26) identifient dans l'ordre, les systèmes de soins de santé, les relations interpersonnelles, et des facteurs personnels comme des obstacles à l'adhésion. En outre, selon les participants, le CHH impacte négativement sur leur qualité de vie générale et entrave leur développement psychosexuel. Les hommes souffrant de CHH se considèrent être des utilisateurs actifs d'internet et comptent sur le web pour trouver des solutions pour trouver des ressources et y recherchent le soutien de leurs pairs (peer-to-peer support). En outre, ils se disent réceptifs à des interventions qui sont basées sur le web pour répondre aux besoins de santé non satisfaits. Cette thèse contribue à la connaissance des soins infirmiers de plusieurs façons. Tout d'abord, elle démontre l'utilité de la HPM comme une construction théorique utile pour comprendre l'adhésion aux traitements et pour l'évaluation des éléments de promotion de santé qui concernent les patients atteints de maladies rares. Deuxièmement, ces données identifient une gamme de besoins de santé non satisfaits qui sont des cibles pour des interventions infirmières centrées sur le patient. Troisièmement, méthodologiquement parlant, cette étude démontre que les méthodes mixtes sont appropriées aux études en soins infirmiers car elles allient les nouvelles technologies qui peuvent effectivement étendre la portée des soins infirmiers (« high-tech »), et l'approche CBPR par des groupes de discussion (« high-touch ») qui ont facilité la compréhension des difficultés que doivent surmonter les hommes souffrant de CHH pour diminuer les disparités en santé et augmenter leur responsabilisation dans la gestion de la maladie rare. Enfin, ces résultats sont prometteurs pour développer des interventions e-santé susceptibles de combler les lacunes dans les soins et l'autonomisation de patients pour une meilleure emprise sur les auto-soins et le bien-être.

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Polyphenols are a major class of bioactive phytochemicals whose consumption may play a role in the prevention of a number of chronic diseases such as cardiovascular diseases, type II diabetes and cancers. Phenol-Explorer, launched in 2009, is the only freely available web-based database on the content of polyphenols in food and their in vivo metabolism and pharmacokinetics. Here we report the third release of the database (Phenol-Explorer 3.0), which adds data on the effects of food processing on polyphenol contents in foods. Data on >100 foods, covering 161 polyphenols or groups of polyphenols before and after processing, were collected from 129 peer-reviewed publications and entered into new tables linked to the existing relational design. The effect of processing on polyphenol content is expressed in the form of retention factor coefficients, or the proportion of a given polyphenol retained after processing, adjusted for change in water content. The result is the first database on the effects of food processing on polyphenol content and, following the model initially defined for Phenol-Explorer, all data may be traced back to original sources. The new update will allow polyphenol scientists to more accurately estimate polyphenol exposure from dietary surveys. Database URL: http://www.phenol-explorer.eu

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Peer-reviewed

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Nowadays, Wireless Sensor Networks (WSN) arealready a very important data source to obtain data about the environment. Thus, they are key to the creation of Cyber-Physical Systems (CPS). Given the popularity of P2P middlewares as ameans to efficiently process information and distribute services, being able to integrate them to WSN¿s is an interesting proposal. JXTA is a widely used P2P middleware that allows peers to easily exchange information, heavily relying on its main architectural highlight, the capability to organize peers with common interests into peer groups. However, right now, approaches to integrate WSNs to a JXTA network seldom take advantage of peer groups. For this reason, in this paper we present jxSensor, an integrationlayer for sensor motes which facilitates the deployment of CPS¿s under this architecture. This integration has been done taking into account JXTA¿s idiosyncrasies and proposing novel ideas,such as the Virtual Peer, a group of sensors that acts as a single entity within the peer group context.