1,809 research outputs found
Web Usage Mining with Evolutionary Extraction of Temporal Fuzzy Association Rules
In Web usage mining, fuzzy association rules that have a temporal property can provide useful knowledge about when associations occur. However, there is a problem with traditional temporal fuzzy association rule mining algorithms. Some rules occur at the intersection of fuzzy sets' boundaries where there is less support (lower membership), so the rules are lost. A genetic algorithm (GA)-based solution is described that uses the flexible nature of the 2-tuple linguistic representation to discover rules that occur at the intersection of fuzzy set boundaries. The GA-based approach is enhanced from previous work by including a graph representation and an improved fitness function. A comparison of the GA-based approach with a traditional approach on real-world Web log data discovered rules that were lost with the traditional approach. The GA-based approach is recommended as complementary to existing algorithms, because it discovers extra rules. (C) 2013 Elsevier B.V. All rights reserved
Temporal fuzzy association rule mining with 2-tuple linguistic representation
This paper reports on an approach that contributes towards the problem of discovering fuzzy association rules that exhibit a temporal pattern. The novel application of the 2-tuple linguistic representation identifies fuzzy association rules in a temporal context, whilst maintaining the interpretability of linguistic terms. Iterative Rule Learning (IRL) with a Genetic Algorithm (GA) simultaneously induces rules and tunes the membership functions. The discovered rules were compared with those from a traditional method of discovering fuzzy association rules and results demonstrate how the traditional method can loose information because rules occur at the intersection of membership function boundaries. New information can be mined from the proposed approach by improving upon rules discovered with the traditional method and by discovering new rules
New neighborhood grocery store increased awareness of food access but did not alter dietary habits or obesity.
National and local policies to improve diet in low-income US populations include increasing physical access to grocery stores and supermarkets in underserved neighborhoods. In a pilot study that evaluated the impacts of opening a new supermarket in a Philadelphia community considered a "food desert"-part of the Pennsylvania Fresh Food Financing Initiative-we found that the intervention moderately improved residents' perceptions of food accessibility. However, it did not lead to changes in reported fruit and vegetable intake or body mass index. The effectiveness of interventions to improve physical access to food and reduce obesity by encouraging supermarkets to locate in underserved areas therefore remains unclear. Nevertheless, the present findings suggest that simply improving a community's retail food infrastructure may not produce desired changes in food purchasing and consumption patterns. Complementary policy changes and interventions may be needed to help consumers bridge the gap between perception and action. The replication of our findings in other settings and research into the factors that influence community residents' receptivity to improved food access are urgently required
Extended Photometry for the DEEP2 Galaxy Redshift Survey: A Testbed for Photometric Redshift Experiments
This paper describes a new catalog that supplements the existing DEEP2 Galaxy
Redshift Survey photometric and spectroscopic catalogs with ugriz photometry
from two other surveys; the Canada-France-Hawaii Legacy Survey (CFHTLS) and the
Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on
the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs.
We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to
provide a more uniform dataset. We have also used this improved photometry to
predict DEEP2 BRI photometry in regions where only poorer measurements were
available previously. In addition, we have included improved astrometry tied to
SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog
contains ~27,000 objects with full ugriz photometry as well as robust
spectroscopic redshift measurements, 64% of which have r > 23. By combining the
secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz
photometry, we have created a catalog that can be used as an excellent testbed
for future photo-z studies, including tests of algorithms for surveys such as
LSST and DES.Comment: 12 pages, 6 figures and 5 tables. Accepted to The Astrophysical
Journal Supplement. Catalogs are publicly available at
http://deep.ps.uci.edu/DR4/photo.extended.htm
Unemployment and Opioid-Related Mortality Rates in U.S. Counties: Investigating Social Capital and Social Isolation–Smoking Pathways
We examine two mechanisms—social capital and sociobehavior—potentially linking unemployment rates to opioid-related mortality and investigate whether the mechanisms differ geographically by the pace of the opioid crisis. Applying path analysis techniques to 2015–2017 opioid-related mortality in U.S. counties (N = 2,648), we find that (1) high unemployment rates are not directly associated with opioid-related mortality rates; (2) high unemployment rates are negatively associated with social capital, and low social capital contributes to high opioid-related mortality; (3) high unemployment rates increase social isolation and the prevalence of smoking, which is positively related to opioid-related mortality; and (4) the pathways are stronger among counties in the states experiencing a rapid growth in opioid-related mortality rates than among those states that are not. Our findings offer insight into how unemployment rates shape the opioid crisis and suggest that the relationship between unemployment and opioid-related mortality is complex
The Nikolaevskiy equation with dispersion
The Nikolaevskiy equation was originally proposed as a model for seismic
waves and is also a model for a wide variety of systems incorporating a
neutral, Goldstone mode, including electroconvection and reaction-diffusion
systems. It is known to exhibit chaotic dynamics at the onset of pattern
formation, at least when the dispersive terms in the equation are suppressed,
as is commonly the practice in previous analyses. In this paper, the effects of
reinstating the dispersive terms are examined. It is shown that such terms can
stabilise some of the spatially periodic traveling waves; this allows us to
study the loss of stability and transition to chaos of the waves. The secondary
stability diagram (Busse balloon) for the traveling waves can be remarkably
complicated.Comment: 24 pages; accepted for publication in Phys. Rev.
Landowners' guide to lease hunting in Missouri (2008)
The information in this guide has been developed to help interested landowners make informed decisions about lease hunting as a potential income-generating opportunity. Many landowners are interested in managing wildlife on their property but cannot justify the expense unless a financial return is achieved. Hunters can provide this supplemental income and often can supply the motivation, labor, equipment and materials. Depending on land management objectives, development of a hunting lease enterprise offers many landowners the opportunity to supplement their income while enhancing wildlife habitat on their property.New 1/97; Revised 7/08/3M
Structures of the DfsB protein family suggest a cationic, helical sibling lethal factor peptide
Bacteria have developed a variety of mechanisms for surviving harsh environmental conditions, nutrient stress and overpopulation. Paenibacillus dendritiformis produces a lethal protein (Slf) that is able to induce cell death in neighbouring colonies and a phenotypic switch in more distant ones. Slf is derived from the secreted precursor protein, DfsB, after proteolytic processing. Here, we present new crystal structures of DfsB homologues from a variety of bacterial species and a surprising version present in the yeast Saccharomyces cerevisiae. Adopting a four-helix bundle decorated with a further three short helices within intervening loops, DfsB belongs to a non-enzymatic class of the DinB fold. The structure suggests that the biologically active Slf fragment may possess a C-terminal helix rich in basic and aromatic residues that suggest a functional mechanism akin to that for cationic antimicrobial peptides
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