40,753 research outputs found
Neutrino Masses and GUT Baryogenesis
We reconsider the GUT-baryogenesis mechanism for generating the baryon
asymmetry of the Universe. The baryon asymmetry is produced by the out of
equilibrium decay of coloured Higgs bosons at the GUT scale, conserving B-L. If
neutrinos are Majorana particles, lepton number violating interactions erase
the lepton number excess, but part of the baryon asymmetry may be preserved,
provided those interactions are not in thermal equilibrium when the sphaleron
processes become effective, at . We analyse whether this
mechanism for baryogenesis is feasible in a variety of GUT models of fermion
masses proposed in the literature, based on horizontal symmetries.Comment: Talk presented at AHEP2003, Valencia, Spain, October 200
Tour-based Travel Mode Choice Estimation based on Data Mining and Fuzzy Techniques
This paper extends tour-based mode choice model, which mainly includes individual trip level interactions, to include
linked travel modes of consecutive trips of an individual. Travel modes of consecutive trip made by an individual in a
household have strong dependency or co-relation because individuals try to maintain their travel modes or use a few
combinations of modes for current and subsequent trips. Traditionally, tour based mode choice models involved nested
logit models derived from expert knowledge. There are limitations associated with this approach. Logit models assumes
i) specific model structure (linear utility model) in advance; and, ii) it holds across an entire historical observations.
These assumptions about the predefined model may be representative of reality, however these rules or heuristics
for tour based mode choice should ideally be derived from the survey data rather than based on expert knowledge/
judgment. Therefore, in this paper, we propose a novel data-driven methodology to address the issues identified in tour
based mode choice. The proposed methodology is tested using the Household Travel Survey (HTS) data of Sydney
metropolitan area and its performances are compared with the state-of-the-art approaches in this area
Matrix Product Density Operators: Renormalization Fixed Points and Boundary Theories
We consider the tensors generating matrix product states and density
operators in a spin chain. For pure states, we revise the renormalization
procedure introduced by F. Verstraete et al. in 2005 and characterize the
tensors corresponding to the fixed points. We relate them to the states
possessing zero correlation length, saturation of the area law, as well as to
those which generate ground states of local and commuting Hamiltonians. For
mixed states, we introduce the concept of renormalization fixed points and
characterize the corresponding tensors. We also relate them to concepts like
finite correlation length, saturation of the area law, as well as to those
which generate Gibbs states of local and commuting Hamiltonians. One of the
main result of this work is that the resulting fixed points can be associated
to the boundary theories of two-dimensional topological states, through the
bulk-boundary correspondence introduced by Cirac et al. in 2011.Comment: 63 pages, Annals of Physics (2016). Accepted versio
Automatic learning of gait signatures for people identification
This work targets people identification in video based on the way they walk
(i.e. gait). While classical methods typically derive gait signatures from
sequences of binary silhouettes, in this work we explore the use of
convolutional neural networks (CNN) for learning high-level descriptors from
low-level motion features (i.e. optical flow components). We carry out a
thorough experimental evaluation of the proposed CNN architecture on the
challenging TUM-GAID dataset. The experimental results indicate that using
spatio-temporal cuboids of optical flow as input data for CNN allows to obtain
state-of-the-art results on the gait task with an image resolution eight times
lower than the previously reported results (i.e. 80x60 pixels).Comment: Proof of concept paper. Technical report on the use of ConvNets (CNN)
for gait recognition. Data and code:
http://www.uco.es/~in1majim/research/cnngaitof.htm
Recommended from our members
Solving the minimum labelling spanning tree problem using hybrid local search
Given a connected, undirected graph whose edges are labelled (or coloured), the minimum
labelling spanning tree (MLST) problem seeks a spanning tree whose edges have the smallest
number of distinct labels (or colours). In recent work, the MLST problem has been shown
to be NP-hard and some effective heuristics (Modified Genetic Algorithm (MGA) and Pilot
Method (PILOT)) have been proposed and analyzed. A hybrid local search method, that we
call Group-Swap Variable Neighbourhood Search (GS-VNS), is proposed in this paper. It is
obtained by combining two classic metaheuristics: Variable Neighbourhood Search (VNS) and
Simulated Annealing (SA). Computational experiments show that GS-VNS outperforms MGA
and PILOT. Furthermore, a comparison with the results provided by an exact approach shows
that we may quickly obtain optimal or near-optimal solutions with the proposed heuristic
Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (III) hfbtho (v3.00): a new version of the program
We describe the new version 3.00 of the code HFBTHO that solves the nuclear
Hartree-Fock (HF) or Hartree-Fock-Bogolyubov (HFB) problem by using the
cylindrical transformed deformed harmonic oscillator basis. In the new version,
we have implemented the following features: (i) the full Gogny force in both
particle-hole and particle-particle channels, (ii) the calculation of the
nuclear collective inertia at the perturbative cranking approximation, (iii)
the calculation of fission fragment charge, mass and deformations based on the
determination of the neck (iv) the regularization of zero-range pairing forces
(v) the calculation of localization functions (vi)MPI interface for large-scale
mass table calculations.Comment: 29 pages, 3 figures, 4 tables; Submitted to Computer Physics
Communication
An Agent Based Model for the Simulation of Transport Demand and Land Use
Agent based modelling has emerged as a promising tool to provide planners with insights on social behaviour and
the interdependencies characterising urban system, particularly with respect to transport and infrastructure planning.
This paper presents an agent based model for the simulation of land use and transport demand of an urban area
of Sydney, Australia. Each individual in the model has a travel diary which comprises a sequence of trips the person
makes in a representative day as well as trip attributes such as travel mode, trip purpose, and departure time.
Individuals are associated with each other by their household relationship, which helps define the interdependencies
of their travel diary and constrains their mode choice. This allows the model to not only realistically reproduce how
the current population uses existing transport infrastructure but more importantly provide comprehensive insight into
future transport demands. The router of the traffic micro-simulator TRANSIMS is incorporated in the model to inform
the actual travel time of each trip and changes of traffic density on the road network. Simulation results show very
good agreement with survey data in terms of the distribution of trips done by transport modes and by trip purposes,
as well as the traffic density along the main road in the study area
- …