1,161 research outputs found
Is the structure of 42Si understood?
Get PDFA more detailed test of the implementation of nuclear forces that drive shell
evolution in the pivotal nucleus \nuc{42}{Si} -- going beyond earlier
comparisons of excited-state energies -- is important. The two leading
shell-model effective interactions, SDPF-MU and SDPF-U-Si, both of which
reproduce the low-lying \nuc{42}{Si}() energy, but whose predictions for
other observables differ significantly, are interrogated by the population of
states in neutron-rich \nuc{42}{Si} with a one-proton removal reaction from
\nuc{43}{P} projectiles at 81~MeV/nucleon. The measured cross sections to the
individual \nuc{42}{Si} final states are compared to calculations that combine
eikonal reaction dynamics with these shell-model nuclear structure overlaps.
The differences in the two shell-model descriptions are examined and linked to
predicted low-lying excited states and shape coexistence. Based on the
present data, which are in better agreement with the SDPF-MU calculations, the
state observed at 2150(13)~keV in \nuc{42}{Si} is proposed to be the ()
level.Comment: accepted in Physical Review Letter
Phase Analysis of Particles Nano Licoo2 as Cathode Materials of Rechargeable Battery Using X-ray Diffractometer
Full text linkResearch of the analysis of particle nano LiCoO2 phase as cathode material of lithium ion based batteries rechargeable using XRD has been done. Particle Nano LiCoO2 are synthesized using planetary milling technique followed by sonication. The morphology of particle nano LiCoO2 are characterized by using Scanning Electron Microscope (SEM) dan Transmission Electron Microscope (TEM), the phase of particle nano LiCoO2 have been analyzed using XRD. The results show that the size of the particle nano LiCoO2 isare 20-40 nm, the phase of n-particles LiCoO2 is rhombohedral, R-3m, with a = b = 2.82 Ã… and c = 14.08 Ã…, where LiCo formed octahedral symmetry, 3-3m, and CO2 to formed tetrahedral symmetry, 63m
Refined saddle-point preconditioners for discretized Stokes problems
Get PDFThis paper is concerned with the implementation of efficient solution algorithms for elliptic problems with constraints. We establish theory which shows that including a simple scaling within well-established block diagonal preconditioners for Stokes problems can result in significantly faster convergence when applying the preconditioned MINRES method. The codes used in the numerical studies are available online
Using Regular Languages to Explore the Representational Capacity of Recurrent Neural Architectures
Get PDFThe presence of Long Distance Dependencies (LDDs) in sequential data poses
significant challenges for computational models. Various recurrent neural
architectures have been designed to mitigate this issue. In order to test these
state-of-the-art architectures, there is growing need for rich benchmarking
datasets. However, one of the drawbacks of existing datasets is the lack of
experimental control with regards to the presence and/or degree of LDDs. This
lack of control limits the analysis of model performance in relation to the
specific challenge posed by LDDs. One way to address this is to use synthetic
data having the properties of subregular languages. The degree of LDDs within
the generated data can be controlled through the k parameter, length of the
generated strings, and by choosing appropriate forbidden strings. In this
paper, we explore the capacity of different RNN extensions to model LDDs, by
evaluating these models on a sequence of SPk synthesized datasets, where each
subsequent dataset exhibits a longer degree of LDD. Even though SPk are simple
languages, the presence of LDDs does have significant impact on the performance
of recurrent neural architectures, thus making them prime candidate in
benchmarking tasks.Comment: International Conference of Artificial Neural Networks (ICANN) 201
Neurological Soft Signs in Individuals with Pathological Gambling
Get PDFIncreased neurological soft signs (NSSs) have been found in a number of neuropsychiatric syndromes, including chemical addiction. The present study examined NSSs related to perceptual-motor and visuospatial processing in a behavioral addiction viz., pathological gambling (PG). As compared to mentally healthy individuals, pathological gamblers displayed significantly poorer ability to copy two- and three-dimensional figures, to recognize objects against a background noise, and to orient in space on a road-map test. Results indicated that PG is associated with subtle cerebral cortical abnormalities. Further prospective clinical research is needed to address the NSSs' origin and chronology (e.g., predate or follow the development of PG) as well as their response to therapeutic interventions and/or their ability to predict such a response
Fourier Method for Approximating Eigenvalues of Indefinite Stekloff Operator
Full text linkWe introduce an efficient method for computing the Stekloff eigenvalues
associated with the Helmholtz equation. In general, this eigenvalue problem
requires solving the Helmholtz equation with Dirichlet and/or Neumann boundary
condition repeatedly. We propose solving the related constant coefficient
Helmholtz equation with Fast Fourier Transform (FFT) based on carefully
designed extensions and restrictions of the equation. The proposed Fourier
method, combined with proper eigensolver, results in an efficient and clear
approach for computing the Stekloff eigenvalues.Comment: 12 pages, 4 figure
Neuro-evolution Methods for Designing Emergent Specialization
Get PDFThis research applies the Collective Specialization Neuro-Evolution (CONE) method to the problem of evolving neural controllers in a simulated multi-robot system. The multi-robot system consists
of multiple pursuer (predator) robots, and a single evader (prey) robot. The CONE method is designed to facilitate behavioral
specialization in order to increase task performance in collective behavior solutions. Pursuit-Evasion is a task that benefits
from behavioral specialization. The performance of prey-capture strategies derived by the CONE method, are compared to those
derived by the Enforced Sub-Populations (ESP) method. Results indicate that the CONE method effectively facilitates behavioral specialization in the team of pursuer
robots. This specialization aids in the derivation of robust prey-capture strategies. Comparatively, ESP was found to be not
as appropriate for facilitating behavioral specialization and effective prey-capture behaviors
Discrete and fuzzy dynamical genetic programming in the XCSF learning classifier system
Full text linkA number of representation schemes have been presented for use within
learning classifier systems, ranging from binary encodings to neural networks.
This paper presents results from an investigation into using discrete and fuzzy
dynamical system representations within the XCSF learning classifier system. In
particular, asynchronous random Boolean networks are used to represent the
traditional condition-action production system rules in the discrete case and
asynchronous fuzzy logic networks in the continuous-valued case. It is shown
possible to use self-adaptive, open-ended evolution to design an ensemble of
such dynamical systems within XCSF to solve a number of well-known test
problems
- …
