12,462 research outputs found
Non-Linear Realisation of the Pure N=4, D=5 Supergravity
We perform the non-linear realisation or the coset formulation of the pure
N=4, D=5 supergravity. We derive the Lie superalgebra which parameterizes a
coset map whose induced Cartan-Maurer form produces the bosonic field equations
of the pure N=4, D=5 supergravity by canonically satisfying the Cartan-Maurer
equation. We also obtain the first-order field equations of the theory as a
twisted self-duality condition for the Cartan-Maurer form within the
geometrical framework of the coset construction.Comment: 12 page
Excessive Memory Usage of the ELLPACK Sparse Matrix Storage Scheme throughout the Finite Element Computations
Sparse matrices are occasionally encountered during solution of various problems by means of numerical methods, particularly the finite element method. ELLPACK sparse matrix storage scheme, one of the most widely used methods due to its implementation ease, is investigated in this study. The scheme uses excessive memory due to its definition. For the conventional finite element method, where the node elements are used, the excessive memory caused by redundant entries in the ELLPACK sparse matrix storage scheme becomes negligible for large scale problems. On the other hand, our analyses show that the redundancy is still considerable for the occasions where facet or edge elements have to be used
Dualisation of the D=9 Matter Coupled Supergravity
We perform the bosonic dualisation of the matter coupled N=1, D=9
supergravity. We derive the Lie superalgebra which parameterizes the coset map
whose Cartan form realizes the second-order bosonic field equations. Following
the non-linear coset construction we present the first-order formulation of the
bosonic field equations as a twisted self-duality condition.Comment: 16 page
Polarization Beam Splitter Based on Self-Collimation of a Hybrid Photonic Crystal
A photonic crystal polarization beam splitter based on photonic band gap and self-collimation effects is designed for optical communication wavelengths. The photonic crystal structure consists of a polarization-insensitive self-collimation region and a splitting region. TM- and TE-polarized waves propagate without diffraction in the self-collimation region, whereas they split by 90 degrees in the splitting region. Efficiency of more than 75% for TM- and TE-polarized light is obtained for a polarization beam splitter size of only 17 ÎĽm x 17 ÎĽm in a wavelength interval of 60 nm including 1.55 ÎĽm
On the Asserted Clash between the Freud and the Bianchi Identities
Through a constructive method it is shown that the claim advanced in recent
times about a clash that should occur between the Freud and the Bianchi
identities in Einstein's general theory of relativity is based on a faulty
argument.Comment: 4 pages, plain Te
Anticipating Information Needs Based on Check-in Activity
In this work we address the development of a smart personal assistant that is
capable of anticipating a user's information needs based on a novel type of
context: the person's activity inferred from her check-in records on a
location-based social network. Our main contribution is a method that
translates a check-in activity into an information need, which is in turn
addressed with an appropriate information card. This task is challenging
because of the large number of possible activities and related information
needs, which need to be addressed in a mobile dashboard that is limited in
size. Our approach considers each possible activity that might follow after the
last (and already finished) activity, and selects the top information cards
such that they maximize the likelihood of satisfying the user's information
needs for all possible future scenarios. The proposed models also incorporate
knowledge about the temporal dynamics of information needs. Using a combination
of historical check-in data and manual assessments collected via crowdsourcing,
we show experimentally the effectiveness of our approach.Comment: Proceedings of the 10th ACM International Conference on Web Search
and Data Mining (WSDM '17), 201
Fine-Tuning on the Effective Patch Radius Expression of the Circular Microstrip Patch Antennas
In this study, the effective patch radius expression for the circular microstrip antennas is improved by means of several manipulations. Departing from previously proposed equations in the literature, one of the most accurate equations is picked up, and this equation is fine-tuned by means of Particle Swarm Optimization technique. Throughout the study, impacts of other parameters (such as the definition of the fitness/objective function, the degree-of-freedom in the proposed effective patch radius expression, the number of measured resonant frequency values) are observed in a controlled manner. Finally, about 3% additional improvement is achieved over a very accurate formula, which was proposed earlier
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