458 research outputs found
Existential questions in (relatively) hyperbolic groups {\it and} Finding relative hyperbolic structures
This arXived paper has two independant parts, that are improved and corrected
versions of different parts of a single paper once named "On equations in
relatively hyperbolic groups".
The first part is entitled "Existential questions in (relatively) hyperbolic
groups". We study there the existential theory of torsion free hyperbolic and
relatively hyperbolic groups, in particular those with virtually abelian
parabolic subgroups. We show that the satisfiability of systems of equations
and inequations is decidable in these groups.
In the second part, called "Finding relative hyperbolic structures", we
provide a general algorithm that recognizes the class of groups that are
hyperbolic relative to abelian subgroups.Comment: Two independant parts 23p + 9p, revised. To appear separately in
Israel J. Math, and Bull. London Math. Soc. respectivel
Study on Two Way Reinforced Concrete Slab Using ANSYS with Different Boundary Conditions and Loading
This paper presents the Finite Element Method (FEM) for analyzing the failure pattern of rectangular slab with various edge conditions. Non-Linear static analysis is carried out using ANSYS 15 Software. Using SOLID65 solid elements, the compressive crushing of concrete is facilitated using plasticity algorithm, while the concrete cracking in tension zone is accommodated by the nonlinear material model. Smeared reinforcement is used and introduced as a percentage of steel embedded in concrete slab. The behavior of the analyzed concrete slab has been observed in terms of the crack pattern and displacement for various loading and boundary conditions. The finite element results are also compared with the experimental data. One of the other objectives of the present study is to show how similar the crack path found by ANSYS program to those observed for the yield line analysis. The smeared reinforcement method is found to be more practical especially for the layered elements like concrete slabs. The value of this method is that it does not require explicit modeling of the rebar, and thus a much coarser mesh can be defined
Twin building lattices do not have asymptotic cut-points
We show that twin building lattices have linear divergence, which implies
that all asymptotic cones are without cut-points.Comment: 7 page
Parabolic groups acting on one-dimensional compact spaces
Given a class of compact spaces, we ask which groups can be maximal parabolic
subgroups of a relatively hyperbolic group whose boundary is in the class. We
investigate the class of 1-dimensional connected boundaries. We get that any
non-torsion infinite f.g. group is a maximal parabolic subgroup of some
relatively hyperbolic group with connected one-dimensional boundary without
global cut point. For boundaries homeomorphic to a Sierpinski carpet or a
2-sphere, the only maximal parabolic subgroups allowed are virtual surface
groups (hyperbolic, or virtually ).Comment: 10 pages. Added a precision on local connectedness for Lemma 2.3,
thanks to B. Bowditc
Transparent conducting sol-gel ATO coatings for display applications by an improved dip coating technique
Transparent conducting coatings of solâgel ATO (antimony-doped tin oxide) were used to improve surface smoothness of commercial sputter-deposited ITO (indium tin oxide) coatings for application as display electrodes. In order to overcome the deteriorating evaporation-cooling during dip coating, the coating solution was heated moderately to 25 °C thus providing the substrate with the required heat. This way, the surface roughness of the ITO could be reduced with an only 45 nm thick ATO coating to Rpv = 3.8 nm (Ra = 0.4 nm) compared to 31 nm (3.8 nm) for the ITO substrate. Another benefit of such additional coating is the possibility to tailor surface properties of the electrodes in wide ranges. This was used to increase the work function of the ITO substrate from initially 4.3â4.6 eV to about 4.8â5.2 eV by the ATO coating
Blockchain-enabled Platform for a Meta Customer Loyalty Program
The competitive value of customer loyalty programs is well-known among marketing strategists. With the emergence of digital platforms, their impact has skyrocketed, with mobile applications replacing more cumbersome physical cards with unique identification numbers on embedded magnetic strips or smart chips. However, these programs generally suffer from two major drawbacks that limit their growth. Firstly, physical cards and mobile applications are restricted to particular merchants and programs. There is no mechanism for customers to transfer their loyalty points between programs or to other customers (although airlines are pioneering efforts in this direction). Secondly, the payoffs of participating in these programs and transactions are not fair to all players (customers, merchants and program operators). Finally, the operational mechanisms of such programs are rarely transparent and traceable; hence, disputes are not easily mediated. Using the innovative strengths of blockchain technology, we present a conceptual architecture for a meta or universal customer loyalty program that supports the design principles of transparency, accountability, fairness and ethics
Whispering gallery mode resonator based ultra-narrow linewidth external cavity semiconductor laser
We demonstrate a miniature self-injection locked DFB laser using resonant
optical feedback from a high-Q crystalline whispering gallery mode resonator.
The linewidth reduction factor is greater than 10,000, with resultant
instantaneous linewidth less than 200 Hz. The minimal value of the Allan
deviation for the laser frequency stability is 3x10^(-12) at the integration
time of 20 us. The laser possesses excellent spectral purity and good long term
stability.Comment: To be published in Optics Letter
Circumcaval ureter with synchronous ipsilateral transitional cell carcinoma of the renal pelvis and the urinary bladder: report of a case and review of the literature
We report a case of concomitant transitional cell carcinoma (TCC) in a circumcaval ureter and invasive bladder cancer. The diagnosis was based on the findings of excretory urography (IVU) and contrast-enhanced computed tomography (CT). IVU showed a typical J-shaped deformity in the dilated right proximal ureteric segment with moderate hydronephrosis and a filling defect in the renal pelvis, while abdominal CT with contrast showed right hydronephrosis with an intrapelvic tumor. The patient underwent radical cystoprostatectomy and nephroureterectomy. No recurrence was detected after 12 months of follow-up.Key Words: Circumcaval, retrocaval, ureter, bladder, transitional cell carcinom
Assessment of dysarthric speech through rhythm metrics
AbstractThis paper reports the results of acoustic investigation based on rhythmic classifications of speech from duration measurements carried out to distinguish dysarthric speech from healthy speech. The Nemours database of American dysarthric speakers is used throughout experiments conducted for this study. The speakers are eleven young adult males with dysarthria caused by cerebral palsy (CP) or head trauma (HT) and one non-dysarthric adult male. Eight different sentences for each speaker were segmented manually to vocalic and intervocalic segmentation (176 sentences). Seventy-four different sentences for each speaker were automatically segmented to voiced and non-voiced intervals (1628 sentences). A two-parameters classification related to rhythm metrics was used to determine the most relevant measures investigated through bi-dimensional representations. Results show the relevance of rhythm metrics to distinguish healthy speech from dysarthrias and to discriminate the levels of dysarthria severity. The majority of parameters was more than 54% successful in classifying speech into its appropriate group (90% for the dysarthric patient classification in the feature space (%V, ÎV)). The results were not significant for voiced and unvoiced intervals relatively to the vocalic and intervocalic intervals (the highest recognition rates were: 62.98 and 90.30% for dysarthric patient and healthy control classification respectively in the feature space (ÎDNV, %DV))
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