mdFoam+: Advanced molecular dynamics in OpenFOAM

This paper introduces mdFoam+, which is an MPI parallelised molecular dynamics (MD) solver implemented entirely within the OpenFOAM software framework. It is open-source and released under the same GNU General Public License (GPL) as OpenFOAM. The source code is released as a publicly open software repository that includes detailed documentation and tutorial cases. Since mdFoam+ is designed entirely within the OpenFOAM C++ object-oriented framework, it inherits a number of key features. The code is designed for extensibility and flexibility, so it is aimed first and foremost as an MD research tool, in which new models and test cases can be developed and tested rapidly. Implementing mdFoam+ in OpenFOAM also enables easier development of hybrid methods that couple MD with continuum-based solvers. Setting up MD cases follows the standard OpenFOAM format, as mdFoam+ also relies upon the OpenFOAM dictionary-based directory structure. This ensures that useful pre- and post-processing capabilities provided by OpenFOAM remain available even though the fully Lagrangian nature of an MD simulation is not typical of most OpenFOAM applications. Results show that mdFoam+ compares well to another well-known MD code (e.g. LAMMPS) in terms of benchmark problems, although it also has additional functionality that does not exist in other open-source MD codes

Bounded Model Checking for Parametric Timed Automata

Abstract. The paper shows how bounded model checking can be ap-plied to parameter synthesis for parametric timed automata with con-tinuous time. While it is known that the general problem is undecidable even for reachability, we show how to synthesize a part of the set of all the parameter valuations under which the given property holds in a model. The results form a complete theory which can be easily applied to parametric verification of a wide range of temporal formulae – we present such an implementation for the existential part of CTL −X. 1 Introduction and related work The growing abundance of complex systems in real world, and their presence in critical areas fuels the research in formal specification and analysis. One of the established methods in systems verification is model checking, where the system is abstracted into the algebraic model (e.g. various versions of Kripke structures

Towards a self-deploying and gliding robot

Strategies for hybrid locomotion such as jumping and gliding are used in nature by many different animals for traveling over rough terrain. This combination of locomotion modes also allows small robots to overcome relatively large obstacles at a minimal energetic cost compared to wheeled or flying robots. In this chapter we describe the development of a novel palm sized robot of 10\,g that is able to autonomously deploy itself from ground or walls, open its wings, recover in midair and subsequently perform goal- directed gliding. In particular, we focus on the subsystems that will in the future be integrated such as a 1.5\,g microglider that can perform phototaxis; a 4.5\,g, bat-inspired, wing folding mechanism that can unfold in only 50\,ms; and a locust-inspired, 7\,g robot that can jump more than 27 times its own height. We also review the relevance of jumping and gliding for living and robotic systems and we highlight future directions for the realization of a fully integrated robot

Do morphological adaptations for gliding in frogs influence clinging and jumping?

The ability to glide has evolved in multiple taxa and is usually associated with highly specialized morphological adaptations. Traits that evolve for one reason, can, however, influence other traits and abilities. In this study, we examined the influence of adaptations for gliding on the jumping and clinging abilities of frogs by comparing specialized flying frogs (Rhacophorus) and unspecialized non-flying frogs (Polypedates) from the family Rhacophoridae. Flying frogs had more webbing, longer legs, and greater clinging abilities than non-flying frogs. Clinging abilities, jumping distance, and gliding distance all correlated positively with body size for both flying and non-flying frogs. We did not, however, find any significant differences between the two groups in horizontal jumping distance or glide distance from a low starting point of 1.56 m. The morphological adaptations that evolved for gliding have not significantly influenced the flying frogs' short-distance jumping abilities, but may have influenced their clinging abilities. Alternatively, there may have been direct selection for clinging ability because of flying frogs' increased need, compared with other frogs, to land on vertical surfaces without slipping off