1,383 research outputs found
Thoughts on Barnette's Conjecture
We prove a new sufficient condition for a cubic 3-connected planar graph to
be Hamiltonian. This condition is most easily described as a property of the
dual graph. Let be a planar triangulation. Then the dual is a cubic
3-connected planar graph, and is bipartite if and only if is
Eulerian. We prove that if the vertices of are (improperly) coloured blue
and red, such that the blue vertices cover the faces of , there is no blue
cycle, and every red cycle contains a vertex of degree at most 4, then is
Hamiltonian.
This result implies the following special case of Barnette's Conjecture: if
is an Eulerian planar triangulation, whose vertices are properly coloured
blue, red and green, such that every red-green cycle contains a vertex of
degree 4, then is Hamiltonian. Our final result highlights the
limitations of using a proper colouring of as a starting point for proving
Barnette's Conjecture. We also explain related results on Barnette's Conjecture
that were obtained by Kelmans and for which detailed self-contained proofs have
not been published.Comment: 12 pages, 7 figure
Tracing mobility patterns through the 6th-5th millennia BC in the Carpathian Basin with strontium and oxygen stable isotope analyses
The complexity of Neolithic population movements and their interpretation through material culture have been the subject of archaeological research for decades. One of the dominant narratives proposes that groups from the Starčevo-Ko¨ro¨ s-Criş complex spread from the central towards the northern Balkans in the Early Neolithic and eventually brought the Neolithic lifestyle into present-day Hungary. Broad geographical migrations were considered to shape the continuous expansion of Neolithic groups and individuals. However, recent archaeological research, aDNA, and isotope analyses challenged the synchronous appearance of specific material culture distributions and human movement dynamics through emphasizing communication networks and socio-cultural transformation processes. This paper seeks to retrace the complexity of Neolithic mobility patterns across Hungary by means of strontium and oxygen stable isotope analyses, which were performed on a total of 718 human dental enamel samples from 55 Neolithic sites spanning the period from the Starčevo to the Balaton-Lasinja culture in Transdanubia and from the Ko¨ro¨s to the Tiszapolga ´ r cultural groups on the Great Hungarian Plain (Alfo¨ ld). This study presents the largest strontium and oxygen isotope sample size for the Neolithic Carpathian Basin and discusses human mobility patterns on various geographical scales and throughout archaeological cultures, chronological periods, and sex and gender categories in a multiproxy analysis. Based on our results, we discuss the main stages of the Neolithisation processes and particularly trace individual movement behaviour such as exogamy patterns within extensive social networks. Furthermore, this paper presents an innovative differentiation between mobility patterns on small, micro-regional, and supra-regional scales, which provides new insights into the complex organisation of Neolithic communities.The complexity of Neolithic population movements and their interpretation through material culture have been the subject of archaeological research for decades. One of the dominant narratives proposes that groups from the Starčevo-Ko¨ro¨ s-Criş complex spread from the central towards the northern Balkans in the Early Neolithic and eventually brought the Neolithic lifestyle into present-day Hungary. Broad geographical migrations were considered to shape the continuous expansion of Neolithic groups and individuals. However, recent archaeological research, aDNA, and isotope analyses challenged the synchronous appearance of specific material culture distributions and human movement dynamics through emphasizing communication networks and socio-cultural transformation processes. This paper seeks to retrace the complexity of Neolithic mobility patterns across Hungary by means of strontium and oxygen stable isotope analyses, which were performed on a total of 718 human dental enamel samples from 55 Neolithic sites spanning the period from the Starčevo to the Balaton-Lasinja culture in Transdanubia and from the Ko¨ro¨s to the Tiszapolga ´ r cultural groups on the Great Hungarian Plain (Alfo¨ ld). This study presents the largest strontium and oxygen isotope sample size for the Neolithic Carpathian Basin and discusses human mobility patterns on various geographical scales and throughout archaeological cultures, chronological periods, and sex and gender categories in a multiproxy analysis. Based on our results, we discuss the main stages of the Neolithisation processes and particularly trace individual movement behaviour such as exogamy patterns within extensive social networks. Furthermore, this paper presents an innovative differentiation between mobility patterns on small, micro-regional, and supra-regional scales, which provides new insights into the complex organisation of Neolithic communities
CNN-based Euler's Elastica Inpainting with Deep Energy and Deep Image Prior
Euler's elastica constitute an appealing variational image inpainting model.
It minimises an energy that involves the total variation as well as the level
line curvature. These components are transparent and make it attractive for
shape completion tasks. However, its gradient flow is a singular, anisotropic,
and nonlinear PDE of fourth order, which is numerically challenging: It is
difficult to find efficient algorithms that offer sharp edges and good rotation
invariance. As a remedy, we design the first neural algorithm that simulates
inpainting with Euler's Elastica. We use the deep energy concept which employs
the variational energy as neural network loss. Furthermore, we pair it with a
deep image prior where the network architecture itself acts as a prior. This
yields better inpaintings by steering the optimisation trajectory closer to the
desired solution. Our results are qualitatively on par with state-of-the-art
algorithms on elastica-based shape completion. They combine good rotation
invariance with sharp edges. Moreover, we benefit from the high efficiency and
effortless parallelisation within a neural framework. Our neural elastica
approach only requires 3x3 central difference stencils. It is thus much simpler
than other well-performing algorithms for elastica inpainting. Last but not
least, it is unsupervised as it requires no ground truth training data.Comment: In Proceedings of the 10th European Workshop on Visual Information
Processing, Lisbon, 202
Heuristic-free Optimization of Force-Controlled Robot Search Strategies in Stochastic Environments
In both industrial and service domains, a central benefit of the use of
robots is their ability to quickly and reliably execute repetitive tasks.
However, even relatively simple peg-in-hole tasks are typically subject to
stochastic variations, requiring search motions to find relevant features such
as holes. While search improves robustness, it comes at the cost of increased
runtime: More exhaustive search will maximize the probability of successfully
executing a given task, but will significantly delay any downstream tasks. This
trade-off is typically resolved by human experts according to simple
heuristics, which are rarely optimal. This paper introduces an automatic,
data-driven and heuristic-free approach to optimize robot search strategies. By
training a neural model of the search strategy on a large set of simulated
stochastic environments, conditioning it on few real-world examples and
inverting the model, we can infer search strategies which adapt to the
time-variant characteristics of the underlying probability distributions, while
requiring very few real-world measurements. We evaluate our approach on two
different industrial robots in the context of spiral and probe search for THT
electronics assembly.Comment: 7 pages, 5 figures, accepted to the 2022 IEEE/RSJ International
Conference on Intelligent Robots and Systems (IROS 2022), Kyoto, Japan For
code and data, see https://github.com/benjaminalt/dps
Frozen Stored Teeth : Autogenous Dentin as an Alternative Augmentation Material in Dentistry
Tooth Shell Technique (TST) with the use of autologous dentin has proven to be a suitable
method of grafting in the context of lateral ridge augmentation. This present feasibility study aimed
to retrospectively evaluate the preservation by lyophilization of processed dentin. Thus, the frozen
stored processed dentin matrix (FST: 19 patients with 26 implants) was re-examined with that of
processed teeth used immediately after extraction (IUT: 23 patients with 32 implants). Parameters of
biological complications, horizontal hard tissue loss, osseointegration, and buccal lamella integrity
were used for evaluation. For complications, the observation period was 5 months. Only one
graft was lost (IUT group). In the area of minor complications, without the loss of an implant or
augmentation, there were two cases of wound dehiscence and one case with inflammation and
suppuration (IUT: n = 3, FST: n = 0). Osseointegration and integrity of the buccal lamella were present
in all implants without exception. Statistically, there was no difference between the groups studied
for the mean resorption of the crestal width and the buccal lamella. Results of this study show that
prepared autologous dentin preserved with a conventional freezer had no disadvantage compared
to immediately use autologous dentin in terms of complications and graft resorption in the context
of TST
Energy dependence of transverse mass spectra of kaons produced in p+p and p+pbar interactions.A compilation
The data on m_T spectra of K0S K+ and K- mesons produced in all inelastic p+p
and p+pbar interactions in the energy range sqrt(s)NN=4.7-1800GeV are compiled
and analyzed. The spectra are parameterized by a single exponential function,
dN/(m_T*dm_T)=C exp(-m_T/T), and the inverse slope parameter T is the main
object of study. The T parameter is found to be similar for K0S, K+ and K-
mesons. It increases monotonically with collision energy from T~30MeV at
sqrt(s)NN=4.7GeV to T~220MeV at sqrt(s)NN=1800GeV. The T parameter measured in
p+p and p+pbar interactions is significantly lower than the corresponding
parameter obtained for central Pb+Pb collisions at all studied energies. Also
the shape of the energy dependence of is different for central Pb+Pb
collisions and p+p(pbar) interactions.Comment: more differential analysis adde
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