2,352 research outputs found
Ultra-Low-Power Superconductor Logic
We have developed a new superconducting digital technology, Reciprocal
Quantum Logic, that uses AC power carried on a transmission line, which also
serves as a clock. Using simple experiments we have demonstrated zero static
power dissipation, thermally limited dynamic power dissipation, high clock
stability, high operating margins and low BER. These features indicate that the
technology is scalable to far more complex circuits at a significant level of
integration. On the system level, Reciprocal Quantum Logic combines the high
speed and low-power signal levels of Single-Flux- Quantum signals with the
design methodology of CMOS, including low static power dissipation, low latency
combinational logic, and efficient device count.Comment: 7 pages, 5 figure
Sampling-Based Query Re-Optimization
Despite of decades of work, query optimizers still make mistakes on
"difficult" queries because of bad cardinality estimates, often due to the
interaction of multiple predicates and correlations in the data. In this paper,
we propose a low-cost post-processing step that can take a plan produced by the
optimizer, detect when it is likely to have made such a mistake, and take steps
to fix it. Specifically, our solution is a sampling-based iterative procedure
that requires almost no changes to the original query optimizer or query
evaluation mechanism of the system. We show that this indeed imposes low
overhead and catches cases where three widely used optimizers (PostgreSQL and
two commercial systems) make large errors.Comment: This is the extended version of a paper with the same title and
authors that appears in the Proceedings of the ACM SIGMOD International
Conference on Management of Data (SIGMOD 2016
Measuring co-authorship and networking-adjusted scientific impact
Appraisal of the scientific impact of researchers, teams and institutions
with productivity and citation metrics has major repercussions. Funding and
promotion of individuals and survival of teams and institutions depend on
publications and citations. In this competitive environment, the number of
authors per paper is increasing and apparently some co-authors don't satisfy
authorship criteria. Listing of individual contributions is still sporadic and
also open to manipulation. Metrics are needed to measure the networking
intensity for a single scientist or group of scientists accounting for patterns
of co-authorship. Here, I define I1 for a single scientist as the number of
authors who appear in at least I1 papers of the specific scientist. For a group
of scientists or institution, In is defined as the number of authors who appear
in at least In papers that bear the affiliation of the group or institution. I1
depends on the number of papers authored Np. The power exponent R of the
relationship between I1 and Np categorizes scientists as solitary (R>2.5),
nuclear (R=2.25-2.5), networked (R=2-2.25), extensively networked (R=1.75-2) or
collaborators (R<1.75). R may be used to adjust for co-authorship networking
the citation impact of a scientist. In similarly provides a simple measure of
the effective networking size to adjust the citation impact of groups or
institutions. Empirical data are provided for single scientists and
institutions for the proposed metrics. Cautious adoption of adjustments for
co-authorship and networking in scientific appraisals may offer incentives for
more accountable co-authorship behaviour in published articles.Comment: 25 pages, 5 figure
A grid-based infrastructure for distributed retrieval
In large-scale distributed retrieval, challenges of latency, heterogeneity, and dynamicity emphasise the importance of infrastructural support in reducing the development costs of state-of-the-art solutions. We present a service-based infrastructure for distributed retrieval which blends middleware facilities and a design framework to ‘lift’ the resource sharing approach and the computational services of a European Grid platform into the domain of e-Science applications. In this paper, we give an overview of the DILIGENT Search Framework and illustrate its exploitation in the field of Earth Science
Extended H? emission line sources from UWISH2
We present the extended source catalogue for the UKIRT Wide Field Infrared Survey for H2 (UWISH2). The survey is unbiased along the inner Galactic Plane from l ? 357° to l ? 65° and |b| ? 1.5° and covers 209 deg2. A further 42.0 and 35.5 deg2 of high dust column density regions have been targeted in Cygnus and Auriga. We have identified 33 200 individual extended H2 features. They have been classified to be associated with about 700 groups of jets and outflows, 284 individual (candidate) planetary nebulae, 30 supernova remnants and about 1300 photodissociation regions. We find a clear decline of star formation activity (traced by H2 emission from jets and photodissociation regions) with increasing distance from the Galactic Centre. About 60 per cent of the detected candidate planetary nebulae have no known counterpart and 25 per cent of all supernova remnants have detectable H2 emission associated with them
Bounded Conjunctive Queries
A query Q is said to be effectively bounded if for all datasets D, there exists a subset DQ of D such that Q(D) = Q(DQ), and the size of DQ and time for fetching DQ are independent of the size of D. The need for studying such queries is evident, since it allows us to compute Q(D) by accessing a bounded dataset DQ, regardless of how big D is. This paper investigates effectively bounded conjunctive queries (SPC) under an access schema A, which specifies indices and cardinality constraints commonly used. We provide characterizations (sufficient and necessary conditions) for determining whether an SPC query Q is effectively bounded under A. We study several problems for deciding whether Q is bounded, and if not, for identifying a minimum set of parameters of Q to instantiate and make Q bounded. We show that these problems range from quadratic-time to NP-complete, and develop efficient (heuristic) algorithms for them. We also provide an algorithm that, given an effectively bounded SPC query Q and an access schema A, generates a query plan for evaluating Q by accessing a bounded amount of data in any (possibly big) dataset. We experimentally verify that our algorithms substantially reduce the cost of query evaluation
The influence of feature selection methods on accuracy, stability and interpretability of molecular signatures
Motivation: Biomarker discovery from high-dimensional data is a crucial
problem with enormous applications in biology and medicine. It is also
extremely challenging from a statistical viewpoint, but surprisingly few
studies have investigated the relative strengths and weaknesses of the plethora
of existing feature selection methods. Methods: We compare 32 feature selection
methods on 4 public gene expression datasets for breast cancer prognosis, in
terms of predictive performance, stability and functional interpretability of
the signatures they produce. Results: We observe that the feature selection
method has a significant influence on the accuracy, stability and
interpretability of signatures. Simple filter methods generally outperform more
complex embedded or wrapper methods, and ensemble feature selection has
generally no positive effect. Overall a simple Student's t-test seems to
provide the best results. Availability: Code and data are publicly available at
http://cbio.ensmp.fr/~ahaury/
Menstrual cycle phase does not predict political conservatism
Recent authors have reported a relationship between women's fertility status, as indexed by menstrual cycle phase, and conservatism in moral, social and political values. We conducted a survey to test for the existence of a relationship between menstrual cycle day and conservatism. 2213 women reporting regular menstrual cycles provided data about their political views. Of these women, 2208 provided information about their cycle date, 1260 provided additional evidence of reliability in self-reported cycle date, and of these, 750 also indicated an absence of hormonal disruptors such as recent hormonal contraception use, breastfeeding or pregnancy. Cycle day was used to estimate day-specific fertility rate (probability of conception); political conservatism was measured via direct self-report and via responses to the "Moral Foundations” questionnaire. We also recorded relationship status, which has been reported to interact with menstrual cycle phase in determining political preferences. We found no evidence of a relationship between estimated cyclical fertility changes and conservatism, and no evidence of an interaction between relationship status and cyclical fertility in determining political attitudes. Our findings were robust to multiple inclusion/exclusion criteria and to different methods of estimating fertility and measuring conservatism. In summary, the relationship between cycle-linked reproductive parameters and conservatism may be weaker or less reliable than previously thought
WhoLoDancE: Towards a methodology for selecting Motion Capture Data across different Dance Learning Practice
<p>In this paper we present the objectives and preliminary work of WhoLoDancE a Research and Innovation Action funded under the European Union‘s Horizon 2020 programme, aiming at using new technologies for capturing and analyzing dance movement to facilitate whole-body interaction learning experiences for a variety of dance genres. Dance is a diverse and heterogeneous practice and WhoLoDancE will develop a protocol for the creation and/or selection of dance sequences drawn from different dance styles for different teaching and learning modalities. As dance learning practice lacks standardization beyond dance genres and specific schools and techniques, one of the first project challenges is to bring together a variety of dance genres and teaching practices and work towards a methodology for selecting the appropriate shots for motion capturing, to acquire kinetic material which will provide a satisfying proof of concept for Learning scenarios of particular genres. The four use cases we are investigating are 1) classical ballet, 2) contemporary dance, 3) flamenco and 4) Greek folk dance.</p
Algebraic Comparison of Partial Lists in Bioinformatics
The outcome of a functional genomics pipeline is usually a partial list of
genomic features, ranked by their relevance in modelling biological phenotype
in terms of a classification or regression model. Due to resampling protocols
or just within a meta-analysis comparison, instead of one list it is often the
case that sets of alternative feature lists (possibly of different lengths) are
obtained. Here we introduce a method, based on the algebraic theory of
symmetric groups, for studying the variability between lists ("list stability")
in the case of lists of unequal length. We provide algorithms evaluating
stability for lists embedded in the full feature set or just limited to the
features occurring in the partial lists. The method is demonstrated first on
synthetic data in a gene filtering task and then for finding gene profiles on a
recent prostate cancer dataset
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