Detecting common scientific workflow fragments using templates and execution provenance

Provenance plays a major role when understanding and reusing the methods applied in a scientic experiment, as it provides a record of inputs, the processes carried out and the use and generation of intermediate and nal results. In the specic case of in-silico scientic experiments, a large variety of scientic workflow systems (e.g., Wings, Taverna, Galaxy, Vistrails) have been created to support scientists. All of these systems produce some sort of provenance about the executions of the workflows that encode scientic experiments. However, provenance is normally recorded at a very low level of detail, which complicates the understanding of what happened during execution. In this paper we propose an approach to automatically obtain abstractions from low-level provenance data by finding common workflow fragments on workflow execution provenance and relating them to templates. We have tested our approach with a dataset of workflows published by the Wings workflow system. Our results show that by using these kinds of abstractions we can highlight the most common abstract methods used in the executions of a repository, relating different runs and workflow templates with each other.

Influence of air drag on the optimal hand launching of a small, round projectile

Conditions leading to a maximum range for a small, round projectile, fired by hand, are discussed taking into account air drag and the dependence of the initial speed on the mass launched. Both the optimal angle of release for given projectile and initial speed, and the optimal radius for given density (i.e., among a bed of pebbles) are determined; an increase on the height of release is found to always decrease the angle and increase the radius. The influence of the projectile mass on the optimal manner of launching is considered. The validity of the approximations used in the analysis is discussed. Results from very simple measurements show good agreement with theory.

Plano del lago de Almenara [Material gráfico] = Plan de lac Almenara = Plan of the lake of Almenara ; Fragmentos de un templo cerca del lago de Almenara = Fragments d'un temple prés du lac d'Almenara = Fragments of a temple near the lake of Almenara

Estampada en la misma hoja con el grabado de "Vista de Almenara, tomada de Murviedro" y con huella de plancha común (53'5 x 31'5 cm)

Fragmentos antiguos [Material gráfico] = Fragmens Antiques = Antique fragments

Estampado con: "Plano del Circo de Sagunto"