774 research outputs found
Fuzzy rule-based system applied to risk estimation of cardiovascular patients
Cardiovascular decision support is one area of increasing research interest. On-going collaborations between clinicians and computer scientists are looking at the application of knowledge discovery in databases to the area of patient diagnosis, based on clinical records. A fuzzy rule-based system for risk estimation of cardiovascular patients is proposed. It uses a group of fuzzy rules as a knowledge representation about data pertaining to cardiovascular patients. Several algorithms for the discovery of an easily readable and understandable group of fuzzy rules are formalized and analysed. The accuracy of risk estimation and the interpretability of fuzzy rules are discussed. Our study shows, in comparison to other algorithms used in knowledge discovery, that classifcation with a group of fuzzy rules is a useful technique for risk estimation of cardiovascular patients. © 2013 Old City Publishing, Inc
Guided by the light: Roost choice and behaviour of urban Rainbow Lorikeets (Trichoglossus haematodus)
1. The formation of large communal roosts is a conspicuous phenomenon associated with a wide range of bird species successfully exploiting urban environments. In many Australian cities, the abundance of the Rainbow Lorikeet (Trichoglossus haematodus), a native parrot, has increased markedly in recent decades, with the species roosting in very large numbers within suburban sites. These roosting locations are noisy and cause significant fouling of the land beneath, resulting in conflict with humans.2. We investigated the selection of roosting sites in this species in Brisbane, Australia, by comparing characteristics of both the general sites of these roosts as well as individual trees used within roosting sites and trees that were avoided.3. Lorikeets used a wide variety of tree types for roosting but demonstrated a clear preference for clumped trees within sparsely treed areas that received significantly more artificial light at night than otherwise suitable sites and trees nearby.4. These features of roosting sites may enhance the detection of nocturnal predators by Rainbow Lorikeets, suggesting a potential positive impact of anthropogenic lighting. Our findings provide valuable insights into the management of roost-related conflicts in urban areas. We encourage further investigations into the possible benefits of artificial light
Mining frequent biological sequences based on bitmap without candidate sequence generation
Biological sequences carry a lot of important genetic information of organisms. Furthermore, there is an inheritance law related to protein function and structure which is useful for applications such as disease prediction. Frequent sequence mining is a core technique for association rule discovery, but existing algorithms suffer from low efficiency or poor error rate because biological sequences differ from general sequences with more characteristics. In this paper, an algorithm for mining Frequent Biological Sequence based on Bitmap, FBSB, is proposed. FBSB uses bitmaps as the simple data structure and transforms each row into a quicksort list QS-list for sequence growth. For the continuity and accuracy requirement of biological sequence mining, tested sequences used during the mining process of FBSB are real ones instead of generated candidates, and all the frequent sequences can be mined without any errors. Comparing with other algorithms, the experimental results show that FBSB can achieve a better performance on both run time and scalability
A class of equations with peakon and pulson solutions (with an Appendix by Harry Braden and John Byatt-Smith)
We consider a family of integro-differential equations depending upon a
parameter as well as a symmetric integral kernel . When and
is the peakon kernel (i.e. up to rescaling) the
dispersionless Camassa-Holm equation results, while the Degasperis-Procesi
equation is obtained from the peakon kernel with . Although these two
cases are integrable, generically the corresponding integro-PDE is
non-integrable. However,for the family restricts to the pulson family of
Fringer & Holm, which is Hamiltonian and numerically displays elastic
scattering of pulses. On the other hand, for arbitrary it is still possible
to construct a nonlocal Hamiltonian structure provided that is the peakon
kernel or one of its degenerations: we present a proof of this fact using an
associated functional equation for the skew-symmetric antiderivative of .
The nonlocal bracket reduces to a non-canonical Poisson bracket for the peakon
dynamical system, for any value of .Comment: Contribution to volume of Journal of Nonlinear Mathematical Physics
in honour of Francesco Caloger
No evidence for intense, cold accretion onto YSOs from measurements of Li in T-Tauri stars
We have used medium resolution spectra to search for evidence that
proto-stellar objects accrete at high rates during their early 'assembly
phase'. Models predict that depleted lithium and reduced luminosity in T-Tauri
stars are key signatures of 'cold' high-rate accretion occurring early in a
star's evolution.
We found no evidence in 168 stars in NGC 2264 and the Orion Nebula Cluster
for strong lithium depletion through analysis of veiling corrected 6708
angstrom lithium spectral line strengths. This suggests that 'cold' accretion
at high rates (M_dot > 5 x 10-4 M_sol yr-1) occurs in the assembly phase of
fewer than 0.5 per cent of 0.3 < M < 1.9 M_sol stars.
We also find that the dispersion in the strength of the 6708 angstrom lithium
line might imply an age spread that is similar in magnitude to the apparent age
spread implied by the luminosity dispersion seen in colour magnitude diagrams.
Evidence for weak lithium depletion (< 10 per cent in equivalent width) that is
correlated with luminosity is also apparent, but we are unable to determine
whether age spreads or accretion at rates less than 5 x 10-4 M_sol yr-1 are
responsible.Comment: 13 pages, 10 figures; Accepted for publication in Monthly Notices of
the Royal Astronomical Society, 2013 June 0
Reasoning with BDI robots: from simulation to physical environment – implementations and limitations
In this paper an overview of the state of research into cognitive robots is given. This is driven by insights arising from research that has moved from simulation to physical robots over the course of a number of sub-projects. A number of major issues arising from seminal research in the area are explored. In particular in the context of advances in the field of robotics and a slowly developing model of cognition and behaviour that is being mapped onto robot colonies. The work presented is ongoing but major themes such as the veracity of data and information, and their effect on robot control architectures are explored. A small number of case studies are presented where the theoretical framework has been used to implement control of physical robots. The limitations of the current research and the wider field of behavioral and cognitive robots are explored
Detection of the spin character of Fe(001) surface states by scanning tunneling microscopy: A theoretical proposal
We consider the magnetic structure on the Fe(001) surface and theoretically
study the scanning tunneling spectroscopy using a spin-polarized tip (SP-STM).
We show that minority-spin surface states induce a strong bias dependence of
the tunneling differential conductance which largely depends on the orientation
of the magnetization in the SP-STM tip relative to the easy magnetization axis
in the Fe(001) surface. We propose to use this effect in order to determine the
spin character of the Fe(001) surface states. This technique can be applied
also to other magnetic surfaces in which surface states are observed.Comment: 5 pages, 4 figure
Using a Role-Driven Race Equity Reform Approach to Mitigate the Effects of America\u27s History of Racism on Food Insecurity
Abstract
Food insecurity, or the lack of reliable access to sufficient quantities of nutritious food, affects African Americans and other minorities disproportionately. This paper examines how America’s history of racism created and sustains the Nation’s racially disparate food system. Food insecurity contributes to hunger. This paper contemplates disparities in other American systems, including education and criminal justice, as exemplars of the broader ramifications of hunger. Finally, the paper examines the potential of individual action to address problems in any system. It champions the adoption of a role-driven race equity reform strategy as a tool to confront the current food insecurity. The strategy emphasizes the capacity of individuals to use the inherent authority of roles at any level of an organization to create change. The paper contends that individual actors, both within and without the food system, can work toward achieving more equitable outcomes in the Nation’s food system
Strain-Induced Conduction Band Spin Splitting in GaAs from First Principles Calculations
We use a recently developed self-consistent GW approximation to present first
principles calculations of the conduction band spin splitting in GaAs under
[110] strain. The spin orbit interaction is taken into account as a
perturbation to the scalar relativistic hamiltonian. These are the first
calculations of conduction band spin splitting under deformation based on a
quasiparticle approach; and because the self-consistent GW scheme accurately
reproduces the relevant band parameters, it is expected to be a reliable
predictor of spin splittings. We also discuss the spin relaxation time under
[110] strain and show that it exhibits an in-plane anisotropy, which can be
exploited to obtain the magnitude and sign of the conduction band spin
splitting experimentally.Comment: 8 pages, 4 figures, 1 tabl
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