101 research outputs found
Symmetry Lie Algebras of Varieties with Applications to Algebraic Statistics
The motivation for this paper is to detect when an irreducible projective
variety V is not toric. We do this by analyzing a Lie group and a Lie algebra
associated to V. If the dimension of V is strictly less than the dimension of
the above mentioned objects, then V is not a toric variety. We provide an
algorithm to compute the Lie algebra of an irreducible variety and use it to
provide examples of non-toric statistical models in algebraic statistics.Comment: 18 pages. Code attached. Comments welcome
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Effect of building gap to improve pedestrian comfort levels and ventilation
Rapid rates of urbanization have resulted into increased concerns of urban environment. Amongst them, wind and thermal
comfort levels for pedestrians have attracted research interest. In this regards, urban wind environment is seen as a crucial
components that can lead to improved thermal comfort levels for pedestrian population. High rise building in modern urban
setting causes high levels of turbulence that renders discomfort to pedestrians. Additionally, a higher frequency of high ris e
buildings at a particular region acts as a shield against the wind flow to the lower buildings beyond them resulting into higher
levels of discomfort to users or residents. Studies conducted on developing wind flow models using Computational Fluid Dynami cs
(CFD) simulations have revealed improvement in interval to height ratios can results into improved wind flow within the
simulation grid. However, high value and demand for land in urban areas renders expansion to be an impractical solution.
Nonetheless, innovative utilization of architectural concepts can be imagined to improve the pedestrian comfort levels through
improved wind permeability. This paper assesses the possibility of through-building gaps being a solution to improve pedestrian
comfort levels
Worldline effective field theory of inspiralling black hole binaries in presence of dark photon and axionic dark matter
We investigate the correction to the potential that gives rise to the bound
orbits and radiation from non-spinning inspiralling binary black holes in a
dark matter environment consisting of axion-like particles and dark photons
using the techniques of Worldline Effective Field Theory. We compute the
conservative dynamics up to PN order for gravitational, electromagnetic, and
Proca fields and up to PN order for the scalar field. The effect of
axion-electromagnetic coupling () arises to the conservative
dynamics at PN order and the kinetic mixing constant () at PN
order. Furthermore, we calculate the radiation due to the various fields
present in our theory. We find that the contribution of to
the gravitational radiation appears at and to the scalar radiation
appears at . We also find that these radiative corrections due to
the coupling vanishes for any orbit confined to a plane
because of the existence of a binormal like term in effective radiative action
but give rise to non-zero contributions for any orbit that lies in three
dimensions. Last but not the least, contributes to the gravitational
radiation at and .Comment: 80 pages, 19 figures, 4 tables, improvements in wording, reference
updated, v2: accepted for publication in JHE
Concise tensors of minimal border rank
We determine defining equations for the set of concise tensors of minimal
border rank in when and the set of concise
minimal border rank -generic tensors when . We solve this classical
problem in algebraic complexity theory with the aid of two recent developments:
the 111-equations defined by Buczy\'{n}ska-Buczy\'{n}ski and results of
Jelisiejew-\v{S}ivic on the variety of commuting matrices. We introduce a new
algebraic invariant of a concise tensor, its 111-algebra, and exploit it to
give a strengthening of Friedland's normal form for -degenerate tensors
satisfying Strassen's equations. We use the 111-algebra to characterize wild
minimal border rank tensors and classify them in .Comment: v2, fina
2 x 2 Phased Array Consisting of Square Loop Antennas for High Gain Wide Angle Scanning With Low Grating Lobes
A 2 × 2 array antenna comprised of conventional hybrid high impedance surface-based reconfigurable square loop antennas (SLAs) as elements is presented. The SLA element has four conducting arms and each arm is fed at the middle by vertical probes, which is connected to a 50 Ω port at the bottom of antenna ground plane. Thus, the SLA element has four feeding ports and it is capable of generating five distinct radiation patterns by using a combination of its feeding ports. Depending upon which of its four ports are excited it can provide four high gain off-boresight tilted beams (8.9 dBi at θmax= 36°) in four different quadrants of the space (tilted beam mode). When all the four ports are simultaneously excited with phases of 0°, 0°, 180°, and 180°, it provides an axial beam (6.5 dBi) at boresight (axial beam mode). By combining these two modes the 2 × 2 array of SLAs can provide a scanning range of-60° to +60° in the elevation plane with high-gain beams (14-11.2 dBi)
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