Search results for "Computer"

Best Practices in Constant pH MD Simulations: Accuracy and Sampling

2022

Various approaches have been proposed to include the effect of pH in molecular dynamics (MD) simulations. Among these, the λ-dynamics approach proposed by Brooks and co-workers [Kong, X.; Brooks III, C. L. J. Chem. Phys.1996, 105, 2414−2423] can be performed with little computational overhead and hfor each typeence be used to routinely perform MD simulations at microsecond time scales, as shown in the accompanying paper [Aho, N. et al. J. Chem. Theory Comput.2022, DOI: 10.1021/acs.jctc.2c00516]. At such time scales, however, the accuracy of the molecular mechanics force field and the parametrization becomes critical. Here, we address these issues and provide the community with guidelines on…

Bayesian semiparametric long memory models for discretized event data

2020

We introduce a new class of semiparametric latent variable models for long memory discretized event data. The proposed methodology is motivated by a study of bird vocalizations in the Amazon rain forest; the timings of vocalizations exhibit self-similarity and long range dependence. This rules out Poisson process based models where the rate function itself is not long range dependent. The proposed class of FRActional Probit (FRAP) models is based on thresholding, a latent process. This latent process is modeled by a smooth Gaussian process and a fractional Brownian motion by assuming an additive structure. We develop a Bayesian approach to inference using Markov chain Monte Carlo and show g…

Toolbox for Distance Estimation and Cluster Validation on Data With Missing Values

2022

Missing data are unavoidable in the real-world application of unsupervised machine learning, and their nonoptimal processing may decrease the quality of data-driven models. Imputation is a common remedy for missing values, but directly estimating expected distances have also emerged. Because treatment of missing values is rarely considered in clustering related tasks and distance metrics have a central role both in clustering and cluster validation, we developed a new toolbox that provides a wide range of algorithms for data preprocessing, distance estimation, clustering, and cluster validation in the presence of missing values. All these are core elements in any comprehensive cluster analy…

Lyapunov quantities and limit cycles in two-dimensional dynamical systems : analytical methods, symbolic computation and visualization

2011

Developing and testing a discrete event simulation model to evaluate budget impacts of diabetes prevention programs

2020

Type 2 diabetes (T2D) is one of the most rapidly increasing non-communicable diseases worldwide. Lifestyle interventions are effective in preventing T2D but also resource intensive. This study evaluated with discrete event simulation (DES) the relative budget impacts of three hypothetical diabetes prevention programs (DPP), including group-based contact intervention, digital program with human coaching and fully automated program. The data for simulation were derived from research literature and national health and population statistics. The model was constructed using the iGrafx Process for Six Sigma software and simulations were carried out for 10 years. All simulated interventions produc…

New Capabilities of the FLUKA Multi-Purpose Code

2022

We would like to deeply thank the CERN Knowledge Transfer and Legal Service teams for their essential and extended support. Our appreciation also goes to the FLUKA.CERN Collaboration Board members for their strong commitment.

Modelling Without a Modelling Language

2018

Developments in computer hardware and programming languages, in this case C++, have made it feasible to write models of concurrent systems under verification in the programming language, instead of some established modelling language such as Promela. While this does not reduce the usefulness of modelling languages, it offers new possibilities that may be advantageous, for instance, when teaching state space ideas to newcomers or when experimenting with new scientific ideas. In earlier work, we were able to express everything else fairly naturally in C++, except the set of transitions. The present study uses C++ lambda functions to represent naturally transitions that consist of a tail state…

Development and use of computational tools for modelling negative hydrogen ion source extraction systems

2013

Motivic Pattern Extraction in Music, and Application to the Study of Tunisian Modal Music

2007

A new methodology for automated extraction of repeated patterns in time-series data is presented, aimed in particular at the analysis of musical sequences. The basic principles consists in a search for closed patterns in a multi-dimensional parametric space. It is shown that this basic mechanism needs to be articulated with a periodic pattern discovery system, implying therefore a strict chronological scanning of the time-series data. Thanks to this modelling global pattern filtering may be avoided and rich and highly pertinent results can be obtained. The modelling has been integrated in a collaborative pro ject between ethnomusicology, cognitive sciences and computer science, aimed at the…

L'ordinateur, outil de productivité de l'enseignant quelle formation initiale en IUFM ?

1992

Les nouvelles technologies de l'information et de la communication – audiovisuel, informatique et télématique – ont connu depuis trente ans en France de grandes actions de mise en oeuvre dans l'enseignement : radio-télévision scolaire, Jeune Téléspectateur Actif, expérimentation « 58 lycées », plan « 10 000 micros », expérimentation « 84 collèges », plan « 100 000 micros », plan IPT, opération « vidéo collège »...Les avancées technologiques de ces dernières années ont favorisé l'évolution des pratiques pédagogiques des enseignants. On est passé progressivement de pratiques indépendantes et isolées de l'informatique, de la télématique et de l'audio visuel à une utilisation combinée qui conce…