66,294 research outputs found
Monte Carlo results for the hydrogen Hugoniot
We propose a theoretical Hugoniot obtained by combining results for the
equation of state (EOS) from the Direct Path Integral Monte Carlo technique
(DPIMC) and those from Reaction Ensemble Monte Carlo (REMC) simulations. The
main idea of such proposal is based on the fact that DPMIC provides
first-principle results for a wide range of densities and temperatures
including the region of partially ionized plasmas. On the other hand, for lower
temperatures where the formation of molecules becomes dominant, DPIMC
simulations become cumbersome and inefficient. For this region it is possible
to use accurate REMC simulations where bound states (molecules) are treated on
the Born-Oppenheimer level using a binding potential calculated by Kolos and
Wolniewicz. The remaining interaction is then reduced to the scattering between
neutral particles which is reliably treated classically applying effective
potentials. The resulting Hugoniot is located between the experimental values
of Knudson {\textit{et al.}} \cite{1} and Collins {\textit{et al.}} \cite{2}.Comment: 10 pges, 2 figures, 2 table
Index to Library Trends Volume 38
published or submitted for publicatio
Rigorous Multiple-Precision Evaluation of D-Finite Functions in SageMath
We present a new open source implementation in the SageMath computer algebra
system of algorithms for the numerical solution of linear ODEs with polynomial
coefficients. Our code supports regular singular connection problems and
provides rigorous error bounds
Quantum Artificial Life in an IBM Quantum Computer
We present the first experimental realization of a quantum artificial life
algorithm in a quantum computer. The quantum biomimetic protocol encodes
tailored quantum behaviors belonging to living systems, namely,
self-replication, mutation, interaction between individuals, and death, into
the cloud quantum computer IBM ibmqx4. In this experiment, entanglement spreads
throughout generations of individuals, where genuine quantum information
features are inherited through genealogical networks. As a pioneering
proof-of-principle, experimental data fits the ideal model with accuracy.
Thereafter, these and other models of quantum artificial life, for which no
classical device may predict its quantum supremacy evolution, can be further
explored in novel generations of quantum computers. Quantum biomimetics,
quantum machine learning, and quantum artificial intelligence will move forward
hand in hand through more elaborate levels of quantum complexity
Faster Gossiping in Bidirectional Radio Networks with Large Labels
We consider unknown ad-hoc radio networks, when the underlying network is
bidirectional and nodes can have polynomially large labels. For this model, we
present a deterministic protocol for gossiping which takes rounds. This improves upon the previous best result for deterministic
gossiping for this model by [Gasienec, Potapov, Pagourtizis, Deterministic
Gossiping in Radio Networks with Large labels, ESA (2002)], who present a
protocol of round complexity for this problem. This
resolves open problem posed in [Gasienec, Efficient gossiping in radio
networks, SIROCCO (2009)], who cite bridging gap between lower and upper bounds
for this problem as an important objective. We emphasize that a salient feature
of our protocol is its simplicity, especially with respect to the previous best
known protocol for this problem
The role of human body movements in mate selection
It is common scientific knowledge, that most of what we say within a conversation is not only expressed by the words meaning alone, but also through our gestures, postures, and body movements. This non-verbal mode is possibly rooted firmly in our human evolutionary heritage, and as such, some scientists argue that it serves as a fundamental assessment and expression tool for our inner qualities. Studies of nonverbal communication have established that a universal, culture-free, non-verbal sign system exists, that is available to all individuals for negotiating social encounters. Thus, it is not only the kind of gestures and expressions humans use in social communication, but also the way these movements are performed, as this seems to convey key information about an individuals quality. Dance, for example, is a special form of movement, which can be observed in human courtship displays. Recent research suggests that people are sensitive to the variation in dance movements, and that dance performance provides information about an individuals mate quality in terms of health and strength. This article reviews the role of body movement in human non-verbal communication, and highlights its significance in human mate preferences in order to promote future work in this research area within the evolutionary psychology framework
Enriching accounts of computerâsupported collaboration by using video data
This paper will discuss the approach to the evaluation of computerâsupported collaborative learning developed in our group over the past ten years. This approach depends on the collection of video data to allow the analysis of key features of problemâsolving behaviour within groups of students working on collaborative learning tasks. Our theoretical framework derives from two sourcesâ the CIAOl framework for evaluating examples of CAL and an analysis of appropriate methods of evaluating computerâsupported collaboration. Our work in this area has been supported by developing the data capture facilities for the CALRG (Computers and Learning Research Group) at the Open University. We will draw on a number of studies to illustrate this approach and will present a brief case study from work done on a computerâsupported learning environment for statistics where we use video records of videoâmediated collaboration. This case study gives an example of the rich data that can be collected using video recording and analysed to increase understanding of computerâsupported collaboration
Variable fused deposition modelling - concept design and tool path generation
Current Fused Deposition Modelling (FDM) techniques use fixed diameter nozzles to deposit a filament of plastic layer by layer. The consequence is that the same small nozzle, essential for fine details, is also used to fill in relatively large volumes. In practice a Pareto-optimal nozzle diameter is chosen that attempts to maximise resolution while minimising build time. This paper introduces a concept for adapting an additive manufacturing system, which exploits a variable diameter nozzle for the fused deposition of polymers. The variable nozzle allows the print resolution and the build speed to become independent variables which may be optimised. The paper discusses a concept design for the variable diameter nozzle to be fitted to a RapMan 3D printer and the software used to generate the tool paths for the extrusion head. The methodology involves the use of existing software solutions to gather basic data from STL files and generate the tool paths. A method for integrating the data and the deposition system is proposed. The challenges and possibilities of the technology are discussed as well as future research
On combinatorial optimisation in analysis of protein-protein interaction and protein folding networks
Abstract: Protein-protein interaction networks and protein folding networks represent prominent research topics at the intersection of bioinformatics and network science. In this paper, we present a study of these networks from combinatorial optimisation point of view. Using a combination of classical heuristics and stochastic optimisation techniques, we were able to identify several interesting combinatorial properties of biological networks of the COSIN project. We obtained optimal or near-optimal solutions to maximum clique and chromatic number problems for these networks. We also explore patterns of both non-overlapping and overlapping cliques in these networks. Optimal or near-optimal solutions to partitioning of these networks into non-overlapping cliques and to maximum independent set problem were discovered. Maximal cliques are explored by enumerative techniques. Domination in these networks is briefly studied, too. Applications and extensions of our findings are discussed
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