4,516 research outputs found
Comparison between Suitable Priors for Additive Bayesian Networks
Additive Bayesian networks are types of graphical models that extend the
usual Bayesian generalized linear model to multiple dependent variables through
the factorisation of the joint probability distribution of the underlying
variables. When fitting an ABN model, the choice of the prior of the parameters
is of crucial importance. If an inadequate prior - like a too weakly
informative one - is used, data separation and data sparsity lead to issues in
the model selection process. In this work a simulation study between two weakly
and a strongly informative priors is presented. As weakly informative prior we
use a zero mean Gaussian prior with a large variance, currently implemented in
the R-package abn. The second prior belongs to the Student's t-distribution,
specifically designed for logistic regressions and, finally, the strongly
informative prior is again Gaussian with mean equal to true parameter value and
a small variance. We compare the impact of these priors on the accuracy of the
learned additive Bayesian network in function of different parameters. We
create a simulation study to illustrate Lindley's paradox based on the prior
choice. We then conclude by highlighting the good performance of the
informative Student's t-prior and the limited impact of the Lindley's paradox.
Finally, suggestions for further developments are provided.Comment: 8 pages, 4 figure
BER-Adaptive RMLSA Algorithm for Wide-Area Flexible Optical Networks
Wide-area optical networks face significant transmission challenges due to the relentless growth of bandwidth demands experienced nowadays. Network operators must consider the relationship between modulation format and maximum reach for each connection request due to the accumulation of physical layer impairments in optical fiber links, to guarantee a minimum quality of service (QoS) and quality of transmission (QoT) to all connection requests. In this work, we present a BER-adaptive solution to solve the routing, modulation format, and spectrum assignment (RMLSA) problem for wide-area elastic optical networks. Our main goal is to maximize successful connection requests in wide-area networks while choosing modulation formats with the highest efficiency possible. Consequently, our technique uses an adaptive bit-error-rate (BER) threshold to achieve communication with the best QoT in the most efficient manner, using the strictest BER value and the modulation format with the smallest bandwidth possible. Additionally, the proposed algorithm relies on 3R regeneration devices to enable long-distances communications if transparent communication cannot be achieved. We assessed our method through simulations for various network conditions, such as the number of regenerators per node, traffic load per user, and BER threshold values. In a scenario without regenerators, the BER-Adaptive algorithm performs similarly to the most relaxed fixed BER threshold studied in blocking probability. However, it ensures a higher QoT to most of the connection requests. The proposed algorithm thrives with the use of regenerators, showing the best performance among the studied solutions, enabling long-distance communications with a high QoT and low blocking probability
Increasing the frequency of hand washing by healthcare workers does not lead to commensurate reductions in staphylococcal infection in a hospital ward
Hand hygiene is generally considered to be the most important measure that can be applied to prevent the spread of healthcare-associated infection (HAI). Continuous emphasis on this intervention has lead to the widespread opinion that HAI rates can be greatly reduced by increased hand hygiene compliance alone. However, this assumes that the effectiveness of hand hygiene is not constrained by other factors and that improved compliance in excess of a given level, in itself, will result in a commensurate reduction in the incidence of HAI. However, several researchers have found the law of diminishing returns to apply to hand hygiene, with the greatest benefits occurring in the first 20% or so of compliance, and others have demonstrated that poor cohorting of nursing staff profoundly influences the effectiveness of hand hygiene measures. Collectively, these findings raise intriguing questions about the extent to which increasing compliance alone can further reduce rates of HAI.
In order to investigate these issues further, we constructed a deterministic Ross-Macdonald model and applied it to a hypothetical general medical ward. In this model the transmission of staphylococcal infection was assumed to occur after contact with the transiently colonized hands of HCWs, who, in turn, acquire contamination only by touching colonized patients. The aim of the study was to evaluate the impact of imperfect hand cleansing on the transmission of staphylococcal infection and to identify, whether there is a limit, above which further hand hygiene compliance is unlikely to be of benefit.
The model demonstrated that if transmission is solely via the hands of HCWs, it should, under most circumstances, be possible to prevent outbreaks of staphylococcal infection from occurring at a hand cleansing frequencies <50%, even with imperfect hand hygiene. The analysis also indicated that the relationship between hand cleansing efficacy and frequency is not linear - as efficacy decreases, so the hand cleansing frequency required to ensure R0<1 increases disproportionately.
Although our study confirmed hand hygiene to be an effective control measure, it demonstrated that the law of diminishing returns applies, with the greatest benefit derived from the first 20% or so of compliance. Indeed, our analysis suggests that there is little benefit to be accrued from very high levels of hand cleansing and that in most situations compliance >40% should be enough to prevent outbreaks of staphylococcal infection occurring, if transmission is solely via the hands of HCWs. Furthermore we identified a non-linear relationship between hand cleansing efficacy and frequency, suggesting that it is important to maximise the efficacy of the hand cleansing process
Evolution of leaf-form in land plants linked to atmospheric CO2 decline in the Late Palaeozoic era
The widespread appearance of megaphyll leaves, with their branched veins and planate form, did not occur until the close of the Devonian period at about 360 Myr ago. This happened about 40 Myr after simple leafless vascular plants first colonized the land in the Late Silurian/Early Devonian, but the reason for the slow emergence of this common feature of present-day plants is presently unresolved. Here we show, in a series of quantitative analyses using fossil leaf characters and biophysical principles, that the delay was causally linked with a 90% drop in atmospheric pCO2 during the Late Palaeozoic era. In contrast to simulations for a typical Early Devonian land plant, possessing few stomata on leafless stems, those for a planate leaf with the same stomatal characteristics indicate that it would have suffered lethal overheating, because of greater interception of solar energy and low transpiration. When planate leaves first appeared in the Late Devonian and subsequently diversified in the Carboniferous period, they possessed substantially higher stomatal densities. This observation is consistent with the effects of the pCO2 on stomatal development and suggests that the evolution of planate leaves could only have occurred after an increase in stomatal density, allowing higher transpiration rates that were sufficient to maintain cool and viable leaf temperatures
Analisis daya saing nilai ekspor udang beku halal food indonesia ke 5 negara tujuan ekspor dalam perspektif islam
Indonesia menjadi salah satu negara pengekspor komoditas perikanan dan menempati peringkat 11  dunia, selain  itu juga menguasai pangsa pasar ekspor sebesar 3,2% pada 2021 (atau mencapai USD5,26 miliar).Perdagangan internasional memegang peranan penting dalam mesin pertumbuhan ekonomi suatu negara. Menurut Adam Smith melalui perdagangan, sumber daya dunia dapat digunakan secara efisien dan dapat memaksimumkan kesejahteraan dunia. Udang merupakan komoditas di sektor perikanan yang memiliki kontribusi besar terhadap nilai ekspor Indonesia. Tujuan penelitian ini dilakukan untk mengetahui daya saing ekspor udang beku sebagai makanan halam dalam perspektif islam. Penelitian ini termasuk dalam kuantitatif. Hasil penelitian menunjukkan bahwa daya saing udang beki indonesia di lima negara dipengaruhi oleh jumlah penduduk dan pendapatan perkapita setiap negara
Pol i ti cal V i ol ence and Excess Li qui di ty i n Egypt: A N ote
Abst ract In t hi s paper w e est i m at e a t i m e-seri es m odel of excess l i qui di t y i n t he Egypt i an banki ng sect or. W hi l e fi nanci al l i beral i zat i on and fi nanci al st abi l i t y are found t o have reduced excess l i qui di t y, t hese effect s have been offset by an i ncrease i n t he num ber of vi ol ent pol i t i cal i nci dent s ari si ng from confl i ct bet w een radi cal Isl am i c groups and t he Egypt i an st at e. The l i nk bet w een pol i t i cal event s and fi nanci al out com es provi des a rat i onal e for econom i c pol i cy i nt ervent i ons by t he i nt ernat i onal com m uni t y i n response t o i ncreases i n pol i t i cal i nst abi l i t y
Clinical characterisation and risk stratification of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy ≥50 years of age
Augmented reality applications for cultural heritage using Kinect
AbstractThis paper explores the use of data from the Kinect sensor for performing augmented reality, with emphasis on cultural heritage applications. It is shown that the combination of depth and image correspondences from the Kinect can yield a reliable estimate of the location and pose of the camera, though noise from the depth sensor introduces an unpleasant jittering of the rendered view. Kalman filtering of the camera position was found to yield a much more stable view. Results show that the system is accurate enough for in situ augmented reality applications. Skeleton tracking using Kinect data allows the appearance of participants to be augmented, and together these facilitate the development of cultural heritage applications.</jats:p
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