403 research outputs found
Irredundant Triangular Decomposition
Triangular decomposition is a classic, widely used and well-developed way to
represent algebraic varieties with many applications. In particular, there
exist sharp degree bounds for a single triangular set in terms of intrinsic
data of the variety it represents, and powerful randomized algorithms for
computing triangular decompositions using Hensel lifting in the
zero-dimensional case and for irreducible varieties. However, in the general
case, most of the algorithms computing triangular decompositions produce
embedded components, which makes it impossible to directly apply the intrinsic
degree bounds. This, in turn, is an obstacle for efficiently applying Hensel
lifting due to the higher degrees of the output polynomials and the lower
probability of success. In this paper, we give an algorithm to compute an
irredundant triangular decomposition of an arbitrary algebraic set defined
by a set of polynomials in C[x_1, x_2, ..., x_n]. Using this irredundant
triangular decomposition, we were able to give intrinsic degree bounds for the
polynomials appearing in the triangular sets and apply Hensel lifting
techniques. Our decomposition algorithm is randomized, and we analyze the
probability of success
Understanding Sample Generation Strategies for Learning Heuristic Functions in Classical Planning
We study the problem of learning good heuristic functions for classical
planning tasks with neural networks based on samples that are states with their
cost-to-goal estimates. It is well known that the learned model quality depends
on the training data quality. Our main goal is to understand better the
influence of sample generation strategies on the performance of a greedy
best-first heuristic search guided by a learned heuristic function. In a set of
controlled experiments, we find that two main factors determine the quality of
the learned heuristic: the regions of the state space included in the samples
and the quality of the cost-to-goal estimates. Also, these two factors are
interdependent: having perfect estimates of cost-to-goal is insufficient if an
unrepresentative part of the state space is included in the sample set.
Additionally, we study the effects of restricting samples to only include
states that could be evaluated when solving a given task and the effects of
adding samples with high-value estimates. Based on our findings, we propose
practical strategies to improve the quality of learned heuristics: three
strategies that aim to generate more representative states and two strategies
that improve the cost-to-goal estimates. Our resulting neural network heuristic
has higher coverage than a basic satisficing heuristic. Also, compared to a
baseline learned heuristic, our best neural network heuristic almost doubles
the mean coverage and can increase it for some domains by more than six times.Comment: 27 page
Research Proposal for an Experiment to Search for the Decay {\mu} -> eee
We propose an experiment (Mu3e) to search for the lepton flavour violating
decay mu+ -> e+e-e+. We aim for an ultimate sensitivity of one in 10^16
mu-decays, four orders of magnitude better than previous searches. This
sensitivity is made possible by exploiting modern silicon pixel detectors
providing high spatial resolution and hodoscopes using scintillating fibres and
tiles providing precise timing information at high particle rates.Comment: Research proposal submitted to the Paul Scherrer Institute Research
Committee for Particle Physics at the Ring Cyclotron, 104 page
The differential-algebraic and bi-Hamiltonian integrability analysis of the Riemann type hierarchy revisited
A differential-algebraic approach to studying the Lax type integrability of
the generalized Riemann type hydrodynamic hierarchy is revisited, its new Lax
type representation and Poisson structures constructed in exact form. The
related bi-Hamiltonian integrability and compatible Poissonian structures of
the generalized Riemann type hierarchy are also discussed.Comment: 18 page
A Xenon Condenser with a Remote Liquid Storage Vessel
We describe the design and operation of a system for xenon liquefaction in
which the condenser is separated from the liquid storage vessel. The condenser
is cooled by a pulse tube cryocooler, while the vessel is cooled only by the
liquid xenon itself. This arrangement facilitates liquid particle detector
research by allowing easy access to the upper and lower flanges of the vessel.
We find that an external xenon gas pump is useful for increasing the rate at
which cooling power is delivered to the vessel, and we present measurements of
the power and efficiency of the apparatus.Comment: 22 pages, 7 figures Corrected typos in authors lis
Viable Supersymmetry and Leptogenesis with Anomaly Mediation
The seesaw mechanism that explains the small neutrino masses comes naturally
with supersymmetric (SUSY) grand unification and leptogenesis. However, the
framework suffers from the SUSY flavor and CP problems, and has a severe
cosmological gravitino problem. We propose anomaly mediation as a simple
solution to all these problems, which is viable once supplemented by the
D-terms for U(1)_Y and U(1)_{B-L}. Even though the right-handed neutrino mass
explicitly breaks U(1)_{B-L} and hence reintroduces the flavor problem, we show
that it lacks the logarithmic enhancement and poses no threat to the framework.
The thermal leptogenesis is then made easily consistent with the gravitino
constraint.Comment: 5 pages, one figure, uses Revtex4; Discussion on the upper bound on
the LSP mass added. The version published in PR
When Worlds Collide: Boundary Management of Adolescent and Young Adult Childhood Cancer Survivors and Caregivers
Adolescent and young adult childhood cancer survivors experience health complications, late or long-term biomedical complications, as well as economic and psychosocial challenges that can have a lifelong impact on their quality-of-life. As childhood cancer survivors transition into adulthood, they must learn to balance their identity development with demands of everyday life and the near- and long-term consequences of their cancer experience, all of which have implications for the ways they use existing technologies and the design of novel technologies. In this study, we interviewed 24 childhood cancer survivors and six caregivers about their cancer survivorship experiences. The results of our analysis indicate that the challenges of transitioning to adulthood as a cancer survivor necessitate the development and management of multiple societal, relational, and personal boundaries, processes that social computing technologies can help or hinder. This paper contributes to the empirical understanding of adolescent and young adult cancer survivors’ social experiences. We further contribute sociotechnical design provocations for researchers, designers, and community members to support survivors
Simple heuristics for the assembly line worker assignment and balancing problem
We propose simple heuristics for the assembly line worker assignment and
balancing problem. This problem typically occurs in assembly lines in sheltered
work centers for the disabled. Different from the classical simple assembly
line balancing problem, the task execution times vary according to the assigned
worker. We develop a constructive heuristic framework based on task and worker
priority rules defining the order in which the tasks and workers should be
assigned to the workstations. We present a number of such rules and compare
their performance across three possible uses: as a stand-alone method, as an
initial solution generator for meta-heuristics, and as a decoder for a hybrid
genetic algorithm. Our results show that the heuristics are fast, they obtain
good results as a stand-alone method and are efficient when used as a initial
solution generator or as a solution decoder within more elaborate approaches.Comment: 18 pages, 1 figur
Capacitar profissionais para trabalhar/difundir a segurança alimentar e nutricional da comunidade
Trabalho apresentado no II Congresso Nacional do PROJETO RONDON, realizado em Florianópolis, SC, no período de 23 a 25 de setembro de 2015 - Universidade Federal de Santa Catarina.O conceito de Segurança alimentar e Nutricional (SAN) é muito amplo, define-se como o direito de todos ao acesso a alimentos de qualidade e em quantidade, sem comprometer o acesso a outras necessidades essenciais. Além disso, a SAN constitui a prática de uma alimentação adequada com alimentos saudáveis, e consumir nutrientes necessários para as atividades diárias de cada cidadão. Sendo assim, foi desenvolvida durante a Operação Bororos - julho/2015, no Conjunto A de atividades no município de Nortelândia/MT, uma oficina que objetivou o esclarecimento dos direitos supracitados a toda população, além de promover o conhecimento sobre os alimentos que estão disponíveis para o consumo, e quais os benefícios que estes podem trazer para a saúde, sua quantidade e variedade adequada. Além de direcionar formas de promoção à alimentação saudável e de auto produção e consumo. Esta oficina foi desenvolvida na Escola Municipal Júlio Praxe de Duarte com auxílio de recursos audiovisuais para 47 pessoas que incluíam profissionais da área da saúde, merendeiras e comunidade em geral. Foram dois dias de atividade no período integral (manhã e tarde), onde no primeiro dia foram desenvolvidas atividades teóricas sobre conceitos de SAN, componentes dos alimentos, grupos alimentares, e aspectos de higiene alimentar. No segundo dia foram desenvolvidas atividades práticas, sendo construída, no período matutino uma horta comunitária no pátio da escola e no período vespertino praticado o monitoramento da SAN para a população, como exemplo, a realização do cálculo do Índice de Massa Corporal (IMC). Foi verificado que houve impacto das informações sobre a população, que se sentiu esclarecida, sendo ouvidos muitos relatos que deixou exposto que o ato de alimentar-se não expressava tanta preocupação com relação a qualidade e propósito dos alimentos. Também constatou-se que o conhecimento sobre como alimentar-se, e o que ingerir, e o porquê consumir tais alimentos apresentaram conceitos novos. Conclui-se desta forma que a atividade promoveu um impacto sobre a comunidade implicando em sua qualidade de vida, e que poderá ser replicada mesmo após a conclusão do trabalho dos rondonistas
Characterization of JBURE-IIb isoform of Canavalia ensiformis (L.) DC urease.
Ureases, nickel-dependent enzymes that catalyze the hydrolysis of urea into ammonia and bicarbonate, are widespread in plants, bacteria, and fungi. Previously, we cloned a cDNA encoding a Canavalia ensiformis urease isoform named JBURE-II, corresponding to a putative smaller urease protein (78 kDa) when compared to other plant ureases. Aiming to produce the recombinant protein, we obtained jbure-IIb, with different 3? and 5? ends, encoding a 90 kDa urease. Three peptides unique to the JBURE-II/-IIb protein were detected by mass spectrometry in seed extracts, indicating that jbure-II/-IIb is a functional gene. Comparative modeling indicates that JBURE-IIb urease has an overall shape almost identical to C. ensiformis major urease JBURE-I with all residues critical for urease activity. The cDNA was cloned into the pET101 vector and the recombinant protein was produced in Escherichia coli. The JBURE-IIb protein, although enzymatically inactive presumably due to the absence of Ni atoms in its active site, impaired the growth of a phytopathogenic fungus and showed entomotoxic properties, inhibiting diuresis of Rhodnius prolixus isolated Malpighian tubules, in concentrations similar to those reported for JBURE-I and canatoxin. The antifungal and entomotoxic properties of the recombinant JBURE-IIb apourease are consistent with a protective role of ureases in plants
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