133 research outputs found

    Design and Test of a High QoS Radio Network for CBTC Systems in Subway Tunnels

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    Communications Based Train Control Systems require high quality radio data communications for train signaling and control. Actually most of these systems use 2.4GHz band with proprietary radio transceivers and leaky feeder as distribution system. All them demand a high QoS radio network to improve the efficiency of railway networks. We present narrow band, broad band and data correlated measurements taken in Madrid underground with a transmission system at 2.4 GHz in a test network of 2 km length in subway tunnels. The architecture proposed has a strong overlap in between cells to improve reliability and QoS. The radio planning of the network is carefully described and modeled with narrow band and broadband measurements and statistics. The result is a network with 99.7% of packets transmitted correctly and average propagation delay of 20ms. These results fulfill the specifications QoS of CBTC systems

    EPRENNID: An evolutionary prototype reduction based ensemble for nearest neighbor classification of imbalanced data

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    Classification problems with an imbalanced class distribution have received an increased amount of attention within the machine learning community over the last decade. They are encountered in a growing number of real-world situations and pose a challenge to standard machine learning techniques. We propose a new hybrid method specifically tailored to handle class imbalance, called EPRENNID. It performs an evolutionary prototype reduction focused on providing diverse solutions to prevent the method from overfitting the training set. It also allows us to explicitly reduce the underrepresented class, which the most common preprocessing solutions handling class imbalance usually protect. As part of the experimental study, we show that the proposed prototype reduction method outperforms state-of-the-art preprocessing techniques. The preprocessing step yields multiple prototype sets that are later used in an ensemble, performing a weighted voting scheme with the nearest neighbor classifier. EPRENNID is experimentally shown to significantly outperform previous proposals

    An insight into imbalanced Big Data classification: outcomes and challenges

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    Big Data applications are emerging during the last years, and researchers from many disciplines are aware of the high advantages related to the knowledge extraction from this type of problem. However, traditional learning approaches cannot be directly applied due to scalability issues. To overcome this issue, the MapReduce framework has arisen as a “de facto” solution. Basically, it carries out a “divide-and-conquer” distributed procedure in a fault-tolerant way to adapt for commodity hardware. Being still a recent discipline, few research has been conducted on imbalanced classification for Big Data. The reasons behind this are mainly the difficulties in adapting standard techniques to the MapReduce programming style. Additionally, inner problems of imbalanced data, namely lack of data and small disjuncts, are accentuated during the data partitioning to fit the MapReduce programming style. This paper is designed under three main pillars. First, to present the first outcomes for imbalanced classification in Big Data problems, introducing the current research state of this area. Second, to analyze the behavior of standard pre-processing techniques in this particular framework. Finally, taking into account the experimental results obtained throughout this work, we will carry out a discussion on the challenges and future directions for the topic.This work has been partially supported by the Spanish Ministry of Science and Technology under Projects TIN2014-57251-P and TIN2015-68454-R, the Andalusian Research Plan P11-TIC-7765, the Foundation BBVA Project 75/2016 BigDaPTOOLS, and the National Science Foundation (NSF) Grant IIS-1447795

    Adverse Childhood Experiences and Use of Cigarettes and Smokeless Tobacco Products

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    Adverse childhood experiences (ACEs) have been linked to increased use of tobacco products later in life. However, studies to date have ignored smokeless tobacco products. To address this, data from the 2011 Behavioral Risk Factor Surveillance System, which interviewed adults 18 years and over (N = 102,716) were analyzed. Logistic regression models were fit to estimate odds ratios of ever smoking, current smoking and current smokeless tobacco use in relation to ACEs. Results showed that less than 4 % of respondents currently used smokeless tobacco products, while 44.95 and 18.57 % reported ever and current smoking, respectively. Physical abuse (OR 1.40; 95 % CI 1.14, 1.72), emotional abuse (OR 1.41; 95 % CI 1.19, 1.67), sexual abuse (OR 0.70; 95 % CI 0.51, 0.95), living with a drug user (OR 1.50; 95 % CI 1.17, 1.93), living with someone who was jailed (OR 1.50; 95 % CI 1.11, 2.02) and having parents who were separated or divorced (OR 1.31; 95 % CI 1.09, 1.57) were associated with smokeless tobacco use in unadjusted models. After accounting for confounders, physical abuse (OR 1.43; 95 % CI 1.16, 1.78), emotional abuse (OR 1.32; 95 % CI 1.10, 1.57), living with a problem drinker (OR 1.30; 95 % CI 1.08, 1.58), living with a drug user (OR 1.31; 95 % CI 1.00, 1.72) and living with adults who treated each other violently (OR 1.30; 95 % CI 1.05, 1.62) were associated with smokeless tobacco use. Living with someone who was mentally ill (OR 0.70; 95 % CI 0.53, 0.92) was associated with smokeless tobacco use after accounting for confounders and all ACEs. Results indicated that some childhood adversities are associated with use of smokeless tobacco products. Special attention is needed to prevent tobacco use of different types among those experiencing ACEs

    A simple deterministic plastoelastohydrodynamic lubrication (PEHL) model in mixed lubrication

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    Most power transmitting components operate under mixed lubrication conditions. Concentrated pressures and smaller lubricant film thickness may cause surface and subsurface stresses to exceed the material yield limit causing permanent geometrical changes. A model was developed to include elastoplastic behaviour within a deterministic unified mixed lubrication framework. Model details are presented and the model is validated against published simulation data. A parametric study to address the effect of material yielding on the contact parameters is performed. It is found that the model successfully produces all the key features of the PEHL contact. The model provides a valuable tool to analyse the PEHL contacts with minimal increase in computational effort and complexity

    Antimicrobial Resistance in Escherichia coli

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    Multidrug resistance in Escherichia coli has become a worrying issue that is increasingly observed in human but also in veterinary medicine worldwide. E. coli is intrinsically susceptible to almost all clinically relevant antimicrobial agents, but this bacterial species has a great capacity to accumulate resistance genes, mostly through horizontal gene transfer. The most problematic mechanisms in E. coli correspond to the acquisition of genes coding for extended-spectrum β-lactamases (conferring resistance to broad-spectrum cephalosporins), carbapenemases (conferring resistance to carbapenems), 16S rRNA methylases (conferring pan-resistance to aminoglycosides), plasmid-mediated quinolone resistance (PMQR) genes (conferring resistance to [fluoro]quinolones), and mcr genes (conferring resistance to polymyxins). Although the spread of carbapenemase genes has been mainly recognized in the human sector but poorly recognized in animals, colistin resistance in E. coli seems rather to be related to the use of colistin in veterinary medicine on a global scale. For the other resistance traits, their cross-transfer between the human and animal sectors still remains controversial even though genomic investigations indicate that extended- spectrum β-lactamase producers encountered in animals are distinct from those affecting humans. In addition, E. coli of animal origin often also show resistances to other—mostly older—antimicrobial agents, including tetracyclines, phenicols, sulfonamides, trimethoprim, and fosfomycin. Plasmids, especially multiresistance plasmids, but also other mobile genetic elements, such as transposons and gene cassettes in class 1 and class 2 integrons, seem to play a major role in the dissemination of resistance genes. Of note, coselection and persistence of resistances to critically important antimicrobial agents in human medicine also occurs through the massive use of antimicrobial agents in veterinary medicine, such as tetracyclines or sulfonamides, as long as all those determinants are located on the same genetic elements

    Determinants of urinary bisphenol A concentrations in Mexican/Mexican-American pregnant women.

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    Prenatal exposure to bisphenol A (BPA) may be associated with adverse health effects in the developing fetus; however, little is known about predictors of BPA exposure during pregnancy. We examined BPA exposure in 491 pregnant women from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort and explored the role of living in the United States on significant dietary predictors of BPA exposure. Women provided urine samples up to two times during pregnancy (n = 866 total samples). We computed the intraclass correlation coefficient (ICC) to evaluate variability in concentrations between collections and used generalized estimating equation (GEE) models to assess predictors of exposure. Geometric mean (GSD) BPA concentrations were 0.9 (2.8) μg/L and 1.0 (2.6) μg/L at the first and second prenatal visits, respectively. We observed greater within- than between-woman variability in urinary BPA concentrations (ICC = 0.22). GEE models suggest that women who lived in the United States their entire life had 38% (CI: − 0.1, 89.3) higher urinary BPA concentrations compared with other immigrant women. Additionally, women who consumed ≥ 3 sodas per day or hamburgers three times a week or more had 58% (CI: 18.0, 112.1) and 20% (CI: − 0.2, 45.2) higher urinary BPA concentrations, respectively, compared with women who consumed no sodas or hamburgers. A higher percentage of women who lived their entire life in the United States reported increased consumption of sodas and hamburgers compared with other immigrant women. Independent of other factors, BPA urinary concentrations were slightly higher when the sample was collected later in the day. As in previous studies, high within-woman variability in urinary BPA concentrations confirms that several samples are needed to properly characterize exposure during pregnancy. Results also suggest that some factors could be modified to minimize exposures during pregnancy in our study participants (e.g., reducing soda and hamburger intake) and that factors associated with acculturation might increase BPA concentrations.This publication was supported by grant numbers: RD 83171001 from the U.S. EPA, and RC ES018792 and P01 ES009605 from NIEHS

    Universal BRCA1/BRCA2 Testing for Ovarian Cancer Patients is Welcomed, but with Care: How Women and Staff Contextualize Experiences of Expanded Access

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    Decreasing costs of genetic testing and advances in treatment for women with cancer with germline BRCA1/BRCA2\textit{BRCA1/BRCA2} mutations have heralded more inclusive genetic testing programs. The Genetic Testing in Epithelial Ovarian Cancer (GTEOC) Study, investigates the feasibility and acceptability of offering genetic testing to all women recently diagnosed with epithelial ovarian cancer (universal genetic testing or UGT). Study participants and staff were interviewed to: (i) assess the impact of UGT (ii) integrate patients' and staff perspectives in the development of new UGT programs. Semi-structured interviews were conducted with twelve GTEOC Study participants and five members of staff involved in recruiting them. The transcripts were transcribed verbatim\textit{verbatim} and analyzed using Interpretative Phenomenological Analysis. There are two super-ordinate themes: motivations and influences around offers of genetic testing\textit{motivations and influences around offers of genetic testing} and impacts of genetic testing in ovarian cancer patients\textit{impacts of genetic testing in ovarian cancer patients}. A major finding is that genetic testing is contextualized within the broader experiences of the women; the impact of UGT was minimized in comparison with the ovarian cancer diagnosis. Women who consent to UGT are motivated by altruism and by their relatives' influence, whilst those who decline are often considered overwhelmed or fearful. Those without a genetic mutation are usually reassured by this result, whilst those with a genetic mutation must negotiate new uncertainties and responsibilities towards their families. Our findings suggest that UGT in this context is generally acceptable to women. However, the period shortly after diagnosis is a sensitive time and some women are emotionally overburdened. UGT is considered a 'family affair' and staff must acknowledge this.This work was supported by Target Ovarian Cancer grant number T005MT. Marc Tischkowitz was supported by funding from the European Union Seventh Framework Program (2007Y2013)/ European Research Council (Grant No. 310018)
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