967 resultados para distributed transaction processing


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Taking the maximum advantage of technological innovations and the investment in them is of key importance for businesses. The IT industry offers a wide range of innovative high-technology solutions to manage information processing and distribution. However for end-user businesses to make informed decisions in this area is challenging. The aim of this research is to identify the key differences in principal solutions, and what the selection criteria should be for those involved. Existing methodologies for software development are classified, and some key criteria are described to help IT system developers and users determine what are the most important factors in system selection, development and deployment. Statistical data is researched and analysed, a theoretical basis is developed and reviewed, key issues from case studies are identified and generalized to be presented along with the conclusions in the current study. The results give a good basis for corporate consideration and provide overall support to the key decisions in developing web-based software. The conclusion is that new web developments should be considered the stakeholders as an evolution of existing business systems, but they should then pay particular attention to the new advantages that web-based software offers in terms of standardised interfaces and procedures, universal deployment opportunities, and a range of other benefits the study highlights.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The prediction filters are well known models for signal estimation, in communications, control and many others areas. The classical method for deriving linear prediction coding (LPC) filters is often based on the minimization of a mean square error (MSE). Consequently, second order statistics are only required, but the estimation is only optimal if the residue is independent and identically distributed (iid) Gaussian. In this paper, we derive the ML estimate of the prediction filter. Relationships with robust estimation of auto-regressive (AR) processes, with blind deconvolution and with source separation based on mutual information minimization are then detailed. The algorithm, based on the minimization of a high-order statistics criterion, uses on-line estimation of the residue statistics. Experimental results emphasize on the interest of this approach.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper analyzes applications of cumulant analysis in speech processing. A special focus is made on different second-order statistics. A dominant role is played by an integral representation for cumulants by means of integrals involving cyclic products of kernels.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Fragile X mental retardation protein (FMRP) regulates neuronal RNA metabolism, and its absence or mutations leads to the Fragile X syndrome (FXS). The β-amyloid precursor protein (APP) is involved in Alzheimer's disease, plays a role in synapse formation, and is upregulated in intellectual disabilities. Here, we show that during mouse synaptogenesis and in human FXS fibroblasts, a dual dysregulation of APP and the α-secretase ADAM10 leads to the production of an excess of soluble APPα (sAPPα). In FXS, sAPPα signals through the metabotropic receptor that, activating the MAP kinase pathway, leads to synaptic and behavioral deficits. Modulation of ADAM10 activity in FXS reduces sAPPα levels, restoring translational control, synaptic morphology, and behavioral plasticity. Thus, proper control of ADAM10-mediated APP processing during a specific developmental postnatal stage is crucial for healthy spine formation and function(s). Downregulation of ADAM10 activity at synapses may be an effective strategy for ameliorating FXS phenotypes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study aimed to examine developmental trends in response inhibition during childhood and to control for possible developmental influence of other basic cognitive processes (such as working memory and processing speed). In addition, we explored the relationships between response inhibition, working memory, and processing speed, as they are thought to be integral to cognitive control. Therefore, we assessed these three cognitive abilities in 159 children aged from 5 to 12. Results showed an improvement in response inhibition ability from 5 to 10 years of age. This improvement remained significant after controlling for the influence of working memory and processing speed. Furthermore, the developmental relationships showed an early differentiation between response inhibition, working memory, and processing speed. Thus, these processes were independent and need to be treated as such in further studies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tietovarastoissa moniulotteinen tietomalli on tehokkain tapa esittää tietoa päätöksentekijöille. Sen toimivuus on hyväksi havaittu monissa eri liiketoimintaympäristöissä. Tehdasympäristöissä on tuhansia mittalaitteita, joista jokainen mittaa uniikkia valmistusprosessiin liittyvää piirrettä. Tässä työssä kehitettiin tietovarasto tehdasmittausten varastointiin käyttäen moniulotteista tietomallia. Havaittiin, että moniulotteisella mallilla tehdasmittaukset voidaan tallentaa joustavalla tavalla ja esittää käyttäjälle mielekkäässä muodossa. Moniulotteinen malli antaa myös erinomaiset keinot tiedon ryhmittelyyn ja vertailuun. Sillä ei kuitenkaan saada vastaavanlaisia hyötyjä kuin klassisissa kaupanalan tietovarastointi esimerkeissä, koska eri mittaukset ovat keskenään hyvin erilaisia. Vaikka mittaukset eivät olekaan aina vertailtavissa tai summattavissa keskenään, saadaan ne moniulotteisella mallilla tallennettua ja luokiteltua loogisesti siten, että käyttäjän on helppo löytää tarvitsemansa tieto. Lisäksi yleisesti tunnettu ja paljon käytetty tietovaraston suunnittelumalli takaa sen, että markkinoilta on saatavissa työkaluja tietovaraston käyttöön. Tietokannan toteutus tehtiin vapaasti levitettävän MySQLtiedonhallintajärjestelmän avulla. Sitä ei ole suunniteltu pääasiassa tietovarastokäyttöön, mutta halpa lisenssi ja hyvä skaalautuvuus tekevät siitä mielenkiintoisen vaihtoehdon. Sitä onkin käytetty luultua enemmän tietovarastoinnissa ja myös monien nimekkäiden organisaatioiden toimesta. Myös tässä työssä todettiin, että MySQL tarjoaa riittävät välineet tietovaraston kehittämiseen.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Snow cover is an important control in mountain environments and a shift of the snow-free period triggered by climate warming can strongly impact ecosystem dynamics. Changing snow patterns can have severe effects on alpine plant distribution and diversity. It thus becomes urgent to provide spatially explicit assessments of snow cover changes that can be incorporated into correlative or empirical species distribution models (SDMs). Here, we provide for the first time a with a lower overestimation comparison of two physically based snow distribution models (PREVAH and SnowModel) to produce snow cover maps (SCMs) at a fine spatial resolution in a mountain landscape in Austria. SCMs have been evaluated with SPOT-HRVIR images and predictions of snow water equivalent from the two models with ground measurements. Finally, SCMs of the two models have been compared under a climate warming scenario for the end of the century. The predictive performances of PREVAH and SnowModel were similar when validated with the SPOT images. However, the tendency to overestimate snow cover was slightly lower with SnowModel during the accumulation period, whereas it was lower with PREVAH during the melting period. The rate of true positives during the melting period was two times higher on average with SnowModel with a lower overestimation of snow water equivalent. Our results allow for recommending the use of SnowModel in SDMs because it better captures persisting snow patches at the end of the snow season, which is important when modelling the response of species to long-lasting snow cover and evaluating whether they might survive under climate change.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

INTRODUCTION: Occupational exposure to grain dust causes respiratory symptoms and pathologies. To decrease these effects, major changes have occurred in the grain processing industry in the last twenty years. However, there are no data on the effects of these changes on workers' respiratory health. OBJECTIVES: The aim of this study was to evaluate the respiratory health of grain workers and farmers involved in different steps of the processing industry of wheat, the most frequently used cereal in Europe, fifteen years after major improvements in collective protective equipment due to mechanisation. MATERIALS AND METHOD: Information on estimated personal exposure to wheat dust was collected from 87 workers exposed to wheat dust and from 62 controls. Lung function (FEV1, FVC, and PEF), exhaled nitrogen monoxide (FENO) and respiratory symptoms were assessed after the period of highest exposure to wheat during the year. Linear regression models were used to explore the associations between exposure indices and respiratory effects. RESULTS: Acute symptoms - cough, sneezing, runny nose, scratchy throat - were significantly more frequent in exposed workers than in controls. Increased mean exposure level, increased cumulative exposure and chronic exposure to more than 6 mg.m (-3) of inhaled wheat dust were significantly associated with decreased spirometric parameters, including FEV1 and PEF (40 ml and 123 ml.s (-1) ), FEV1 and FVC (0.4 ml and 0.5 ml per 100 h.mg.m (-3) ), FEV1 and FVC (20 ml and 20 ml per 100 h at >6 mg.m (-3) ). However, no increase in FENO was associated with increased exposure indices. CONCLUSIONS: The lung functions of wheat-related workers are still affected by their cumulative exposure to wheat dust, despite improvements in the use of collective protective equipment.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Today’s commercial web sites are under heavy user load and they are expected to be operational and available at all times. Distributed system architectures have been developed to provide a scalable and failure tolerant high availability platform for these web based services. The focus on this thesis was to specify and implement resilient and scalable locally distributed high availability system architecture for a web based service. Theory part concentrates on the fundamental characteristics of distributed systems and presents common scalable high availability server architectures that are used in web based services. In the practical part of the thesis the implemented new system architecture is explained. Practical part also includes two different test cases that were done to test the system's performance capacity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

NlmCategory="UNASSIGNED">Objects' borders are readily perceived despite absent contrast gradients, e.g. due to poor lighting or occlusion. In humans, a visual evoked potential (VEP) correlate of illusory contour (IC) sensitivity, the "IC effect", has been identified with an onset at ~90ms and generators within bilateral lateral occipital cortices (LOC). The IC effect is observed across a wide range of stimulus parameters, though until now it always involved high-contrast achromatic stimuli. Whether IC perception and its brain mechanisms differ as a function of the type of stimulus cue remains unknown. Resolving such will provide insights on whether there is a unique or multiple solutions to how the brain binds together spatially fractionated information into a cohesive perception. Here, participants discriminated IC from no-contour (NC) control stimuli that were either comprised of low-contrast achromatic stimuli or instead isoluminant chromatic contrast stimuli (presumably biasing processing to the magnocellular and parvocellular pathways, respectively) on separate blocks of trials. Behavioural analyses revealed that ICs were readily perceived independently of the stimulus cue-i.e. when defined by either chromatic or luminance contrast. VEPs were analysed within an electrical neuroimaging framework and revealed a generally similar timing of IC effects across both stimulus contrasts (i.e. at ~90ms). Additionally, an overall phase shift of the VEP on the order of ~30ms was consistently observed in response to chromatic vs. luminance contrast independently of the presence/absence of ICs. Critically, topographic differences in the IC effect were observed over the ~110-160ms period; different configurations of intracranial sources contributed to IC sensitivity as a function of stimulus contrast. Distributed source estimations localized these differences to LOC as well as V1/V2. The present data expand current models by demonstrating the existence of multiple, cue-dependent circuits in the brain for generating perceptions of illusory contours.