4,147 research outputs found
A Reverse Hex Solver
We present Solrex,an automated solver for the game of Reverse Hex.Reverse
Hex, also known as Rex, or Misere Hex, is the variant of the game of Hex in
which the player who joins her two sides loses the game. Solrex performs a
mini-max search of the state space using Scalable Parallel Depth First Proof
Number Search, enhanced by the pruning of inferior moves and the early
detection of certain winning strategies. Solrex is implemented on the same code
base as the Hex program Solver, and can solve arbitrary positions on board
sizes up to 6x6, with the hardest position taking less than four hours on four
threads.Comment: Presented at Computers and Games 2016 Leiden, International
Conference on Computers and Games. Springer International Publishing, 201
Magic numbers in the discrete tomography of cyclotomic model sets
We report recent progress in the problem of distinguishing convex subsets of
cyclotomic model sets by (discrete parallel) X-rays in prescribed
-directions. It turns out that for any of these model sets
there exists a `magic number' such that any two
convex subsets of can be distinguished by their X-rays in any set
of prescribed -directions. In particular, for
pentagonal, octagonal, decagonal and dodecagonal model sets, the least possible
numbers are in that very order 11, 9, 11 and 13.Comment: 6 pages, 1 figure; based on the results of arXiv:1101.4149 [math.MG];
presented at Aperiodic 2012 (Cairns, Australia
Simulation of an Optional Strategy in the Prisoner's Dilemma in Spatial and Non-spatial Environments
This paper presents research comparing the effects of different environments
on the outcome of an extended Prisoner's Dilemma, in which agents have the
option to abstain from playing the game. We consider three different pure
strategies: cooperation, defection and abstinence. We adopt an evolutionary
game theoretic approach and consider two different environments: the first
which imposes no spatial constraints and the second in which agents are placed
on a lattice grid. We analyse the performance of the three strategies as we
vary the loner's payoff in both structured and unstructured environments.
Furthermore we also present the results of simulations which identify scenarios
in which cooperative clusters of agents emerge and persist in both
environments.Comment: 12 pages, 8 figures. International Conference on the Simulation of
Adaptive Behavio
Peramorphosis, an evolutionary developmental mechanism in neotropical bat skull diversity
Background
The neotropical leaf‐nosed bats (Chiroptera, Phyllostomidae) are an ecologically diverse group of mammals with distinctive morphological adaptations associated with specialized modes of feeding. The dramatic skull shape changes between related species result from changes in the craniofacial development process, which brings into focus the nature of the underlying evolutionary developmental processes.
Results
In this study, we use three‐dimensional geometric morphometrics to describe, quantify, and compare morphological modifications unfolding during evolution and development of phyllostomid bats. We examine how changes in development of the cranium may contribute to the evolution of the bat craniofacial skeleton. Comparisons of ontogenetic trajectories to evolutionary trajectories reveal two separate evolutionary developmental growth processes contributing to modifications in skull morphogenesis: acceleration and hypermorphosis.
Conclusion
These findings are consistent with a role for peramorphosis, a form of heterochrony, in the evolution of bat dietary specialists
«Prozessintelligenz» : Gegenstand und Ziele der Studie
«Intelligente Prozesse, «intelligentes Prozessmanagement», «iBPM» sind Schlagworte, die in erster Linie eingesetzt werden, um Technologien zu vermarkten. Die Begriffe lassen viel Raum für Interpretation und Assoziationen. Können Unternehmen den Hype ignorieren oder bietet «Prozessintelligenz» die Chance, das Prozessmanagement aus einem anderen Blickwinkel zu betrachten und weiterzuentwickeln? Doch was ist Prozessintelligenz? Welche Lösungsansätze, Erfahrungen und Erfolgsmuster gibt es bereits in Unternehmen? Welche Methoden und Werkzeuge kommen zum Einsatz, um Prozesse «intelligenter» zu machen? Diesen Fragen hat sich die Business-Process-Management-Studie 2015 gestellt, mit der das Institut für Wirtschaftsinformatik der Zürcher Hochschule für Angewandte Wissenschaften School of Management and Law seit 2011 regelmässig Status quo und Best Practices im deutschsprachigen Raum erhebt
Has education lost sight of children?
The reflections presented in this chapter are informed by clinical and personal experiences of school education in the UK. There are many challenges for children and young people in the modern education system and for the professionals who support them. In the UK, there are significant gaps between the highly selective education provided to those who pay privately for it and to the majority of those educated in the state-funded system. Though literacy rates have improved around the world, many children, particularly boys, do not finish their education for reasons such as boredom, behavioural difficulties or because education does not ‘pay’. Violence, bullying, and sexual harassment are issues faced by many children in schools and there are disturbing trends of excluding children who present with behavioural problems at school whose origins are not explored. Excluded children are then educated with other children who may also have multiple problems which often just make the situation worse. The experience of clinicians suggests that school-related mental health problems are increasing in severity. Are mental health services dealing with the consequences of an education system that is not meeting children’s needs? An education system that is testing- and performance-based may not be serving many children well if it is driving important decisions about them at increasingly younger ages. Labelling of children and setting them on educational career paths can occur well before they reach secondary schools, limiting potential very early on in their developmental trajectory. Furthermore, the emphasis at school on testing may come at the expense of creativity and other forms of intelligence, which are also valuable and important. Meanwhile the employment marketplace requires people with widely different skills, with an emphasis on innovation, creativity, and problem solving. Is education losing sight of the children it is educating
Environmental life cycle assessment of wire arc additively manufactured steel structural components
Wire arc additive manufacturing (WAAM) enables the production of structural components with topologically optimised geometries thus leading to significant self-weight reductions for a given load-carrying capacity. A common question arises regarding the environmental performance of WAAM structural components in comparison with conventional steel structural components. Thus, a comparative cradle-to-gate life cycle assessment has been conducted where the environmental impact of producing a topologically optimised WAAM steel beam is compared with that of producing a conventional hot-rolled steel I-beam. The beams are 2 m long, simply-supported and loaded vertically at midspan. The impact of using either carbon steel or stainless steel is investigated. The results demonstrate that the carbon steel and stainless steel WAAM beams have 7% and 24%, respectively, lower climate change impact than the corresponding I-beams. It is concluded that WAAM can lead to lower CO2-eq. emissions than conventional hot-rolling, provided that mass reductions of the order of 50% (which are readily attainable) can be achieved by employing WAAM in conjunction with, for instance, topology optimisation. Furthermore, it is shown that the shielding gas contributes greatly to the environmental impact of WAAM, and that, by using higher deposition rates or by utilising renewable energy sources, the impact of WAAM can be reduced by more than 30%
Comparative cytogenetic analysis between Lonchorhina aurita and Trachops cirrhosus (Chiroptera, Phyllostomidae)
Phyllostomidae comprises the most diverse family of neotropical bats, its wide range of morphological features leading to uncertainty regarding phylogenetic relationships. Seeing that cytogenetics is one of the fields capable of providing support for currently adopted classifications through the use of several markers, a comparative analysis between two Phyllostomidae species was undertaken in the present study, with a view to supplying datasets for the further establishment of Phyllostomidae evolutionary relationships. Karyotypes of Lonchorhina aurita (2n = 32; FN = 60) and Trachops cirrhosus (2n = 30; FN = 56) were analyzed by G- and C-banding, silver nitrate staining (Ag-NOR) and base-specific fluorochromes. Chromosomal data obtained for both species are in agreement with those previously described, except for X chromosome morphology in T. cirrhosus, hence indicating chromosomal geographical variation in this species. A comparison of G-banding permitted the identification of homeologies in nearly all the chromosomes. Furthermore, C-banding and Ag-NOR patterns were comparable to what has already been observed in the family. In both species CMA3 /DA/DAPI staining revealed an R-banding-like pattern with CMA 3 , whereas DAPI showed uniform staining in all the chromosomes. Fluorochrome staining patterns for pericentromeric constitutive heterochromatin (CH) regions, as well as for nucleolar organizing regions (NORs), indicated heterogeneity regarding these sequences among Phyllostomidae species
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