646 research outputs found

    Distribution of Mutual Information

    Full text link
    The mutual information of two random variables i and j with joint probabilities t_ij is commonly used in learning Bayesian nets as well as in many other fields. The chances t_ij are usually estimated by the empirical sampling frequency n_ij/n leading to a point estimate I(n_ij/n) for the mutual information. To answer questions like "is I(n_ij/n) consistent with zero?" or "what is the probability that the true mutual information is much larger than the point estimate?" one has to go beyond the point estimate. In the Bayesian framework one can answer these questions by utilizing a (second order) prior distribution p(t) comprising prior information about t. From the prior p(t) one can compute the posterior p(t|n), from which the distribution p(I|n) of the mutual information can be calculated. We derive reliable and quickly computable approximations for p(I|n). We concentrate on the mean, variance, skewness, and kurtosis, and non-informative priors. For the mean we also give an exact expression. Numerical issues and the range of validity are discussed.Comment: 8 page

    Comparison of type I collagens and MMP-2 proteins in temporomandibular joint of young and old mice

    Get PDF
    Background: The effects of ageing on the histopathological changes of tem­poromandibular joint (TMJ) and the existence and age related alterations of immunochemical expressions of type I collagen and matrix metalloproteinase-2 (MMP-2) proteins was aimed to be displayed. Materials and methods: In this study, 14 Balb/C type white mice (50– –80 g) were included. Groups were organised as group 1 — 2-month-old young animals (n = 7) and group 2 — 18-month-old old animals (n = 7). Of the paraffin embedded tissues 4–5 μm thick sections were taken and immunohisto­chemical stainings of haematoxylin-eosin, type-1 collagen and MMP-2 were performed. Results: Collagen bundles showed sagittal and oblique localisations in the young mice, which were comprised of compact collagen bundle layers positioned alterna­tely. While collagen bundle fragmentation was observed in the disks of old mice, some disk regions showed ruptures. In the old mice a decrease in blood vessels, structural impairments and dilatation in arterioles and venules were detected. In the TMJ tissues of the young mice type I collagen and MMP-2 expressions were increased, while they were decreased in old mice. In the MMP-2 H-score evaluation young mice showed significant increase compared to the old mice. Conclusions: Occurrence of degenerations in the collagen structure of TMJ and decimation in the matrix metalloproteases were observed with age. (Folia Morphol 2018; 77, 2: 329–334

    Event Detection in Aerospace Systems using Centralized Sensor Networks: A Comparative Study of Several Methodologies

    Get PDF
    Recent advances in micro electromechanical systems technology, digital electronics, and wireless communications have enabled development of low-cost, low-power, multifunctional miniature smart sensors. These sensors can be deployed throughout a region in an aerospace vehicle to build a network for measurement, detection and surveillance applications. Event detection using such centralized sensor networks is often regarded as one of the most promising health management technologies in aerospace applications where timely detection of local anomalies has a great impact on the safety of the mission. In this paper, we propose to conduct a qualitative comparison of several local event detection algorithms for centralized redundant sensor networks. The algorithms are compared with respect to their ability to locate and evaluate an event in the presence of noise and sensor failures for various node geometries and densities

    Decoding behavioural responses of green hotel guests: A deeper insight into the application of the theory of planned behaviour

    Get PDF
    Purpose This study aims to present a unique perspective on the application of the theory of planned behaviour (TPB) in the context of the green lodging industry via configurational modelling of three TPB dimensions in formulating hotel visitors’ behavioural responses. Attitude towards behaviour, subjective norms and perceived behavioural control are the three indicators of TPB used to predict guests’ continued intention to use and recommend green hotels on Cyprus, a Mediterranean island with a fragile ecological system. Design/methodology/approach A questionnaire-based survey is used to evaluate the study’s objectives. A total of 320 guests of green hotels were approached between June and July 2017 and invited to participate. Among them, 260 valid cases were obtained and used for data analysis. The structural model was tested using structural equation modelling (SEM), the configurational model was assessed using the fuzzy-set qualitative comparative analysis (fsQCA) and the necessary predictor was evaluated using the necessary condition analysis (NCA). Findings The SEM results revealed that attitudes regarding behaviour increased the continued intention to visit and recommend green hotels. Similarly, subjective norms enhanced the guests’ desired behavioural responses. Perceived behavioural control boosted their continued intention to visit, but this was insufficient for predicting green hotel guests’ intention to recommend. The fsQCA results indicated that two causal models explained the conditions of both high and low levels of behavioural responses. The NCA results showed that attitude towards behaviour was the only necessary condition of the two expected behavioural responses. Originality/value Several previous studies have tried to modify, decompose or merge the TPB to provide theoretical support for proposed conceptual models indicating visitors’ behaviours. Beyond such attempts, pragmatic analytical approaches (e.g. set-theoretic method) should be applied to present a comprehensive perspective on the association of TPB indicators in decoding the complexity of customers’ behaviours. To the best of the authors’ knowledge, this study is among the first in hospitality research to use three TPB indicators and three analytical approaches to extend the knowledge of guests’ behaviours related to green hotels

    The effects of external and internal factors on competitive advantage—moderation of market dynamism and mediation of customer relationship building

    Get PDF
    Using a resource-based view and dynamic capabilities approach, this study investigates both the internal and external factors influencing competitive advantage in the hotel industry. For this purpose, we examine how organizational capabilities may lead to customer relationship building and in turn to competitive advantage. We further test the moderation role of market dynamism on the relationship between organizational capabilities and customer relationship building, and also investigate the mediation effect of customer relationship building on the association between organizational capabilities and competitive advantage. A questionnaire-based study was conducted among hotel employees in Northern Cyprus to test the conceptual model. A set of approaches was applied to detect common method bias and test the validity and reliability of the questionnaire. Correlation and regression analyses were conducted to evaluate the relationships between the variables, and bootstrapping analysis was applied to assess the mediation and moderation effects. The results revealed that organizational capabilities enhance customer relationship building and competitive advantage. Market dynamism as an external factor moderates the relationship between organizational capabilities and customer relationship building. There is also an indirect association between organizational capabilities and competitive advantage through the mediation of customer relationship building. The theoretical and practical implications of the findings are discussed

    A realistic evaluation of indoor positioning systems based on Wi-Fi fingerprinting: The 2015 EvAAL–ETRI competition

    Get PDF
    Pre-print versionThis paper presents results from comparing different Wi-Fi fingerprinting algorithms on the same private dataset. The algorithms where realized by independent teams in the frame of the off-site track of the EvAAL-ETRI Indoor Localization Competition which was part of the Sixth International Conference on Indoor Positioning and Indoor Navigation (IPIN 2015). Competitors designed and validated their algorithms against the publicly available UJIIndoorLoc database which contains a huge reference- and validation data set. All competing systems were evaluated using the mean error in positioning, with penalties, using a private test dataset. The authors believe that this is the first work in which Wi-Fi fingerprinting algorithm results delivered by several independent and competing teams are fairly compared under the same evaluation conditions. The analysis also comprises a combined approach: Results indicate that the competing systems where complementary, since an ensemble that combines three competing methods reported the overall best results.We would like to thank Francesco Potortì, Paolo Barsocchi, Michele Girolami and Kyle O’Keefe for their valuable help in organizing and spread the EVAALETRI competition and the off-site track. We would also like to thank the TPC members Machaj Juraj, Christos Laoudias, Antoni Pérez-Navarro and Robert Piché for their valuable comments, suggestions and reviews. Parts of this work were funded in the frame of the Spanish Ministry of Economy and Competitiveness through the “Metodologiías avanzadas para el diseño, desarrollo, evaluación e integración de algoritmos de localización en interiores” project (Proyectos I+D Excelencia, código TIN2015-70202-P) and the “Red de Posicionamiento y Navegación en Interiores” network (Redes de Excelencia, código TEC2015-71426- REDT). Parts of this work were funded in the frame of the German federal Ministry of Education and Research programme "FHprofUnt2013" under contract 03FH035PB3 (Project SPIRIT).info:eu-repo/semantics/acceptedVersio

    Genome-wide DNA methylation analysis of transient neonatal diabetes type 1 patients with mutations in ZFP57

    Get PDF
    BackgroundTransient neonatal diabetes mellitus 1 (TNDM1) is a rare imprinting disorder characterized by intrautering growth retardation and diabetes mellitus usually presenting within the first six weeks of life and resolves by the age of 18 months. However, patients have an increased risk of developing diabetes mellitus type 2 later in life. Transient neonatal diabetes mellitus 1 is caused by overexpression of the maternally imprinted genes PLAGL1 and HYMAI on chromosome 6q24. One of the mechanisms leading to overexpression of the locus is hypomethylation of the maternal allele of PLAGL1 and HYMAI. A subset of patients with maternal hypomethylation at PLAGL1 have hypomethylation at additional imprinted loci throughout the genome, including GRB10, ZIM2 (PEG3), MEST (PEG1), KCNQ1OT1 and NESPAS (GNAS-AS1). About half of the TNDM1 patients carry mutations in ZFP57, a transcription factor involved in establishment and maintenance of methylation of imprinted loci. Our objective was to investigate whether additional regions are aberrantly methylated in ZFP57 mutation carriers.MethodsGenome-wide DNA methylation analysis was performed on four individuals with homozygous or compound heterozygous ZFP57 mutations, three relatives with heterozygous ZFP57 mutations and five controls. Methylation status of selected regions showing aberrant methylation in the patients was verified using bisulfite-sequencing.ResultsWe found large variability among the patients concerning the number and identity of the differentially methylated regions, but more than 60 regions were aberrantly methylated in two or more patients and a novel region within PPP1R13L was found to be hypomethylated in all the patients. The hypomethylated regions in common between the patients are enriched for the ZFP57 DNA binding motif.ConclusionsWe have expanded the epimutational spectrum of TNDM1 associated with ZFP57 mutations and found one novel region within PPP1R13L which is hypomethylated in all TNDM1 patients included in this study. Functional studies of the locus might provide further insight into the etiology of the disease.<br/

    Collective Intelligence for Control of Distributed Dynamical Systems

    Full text link
    We consider the El Farol bar problem, also known as the minority game (W. B. Arthur, ``The American Economic Review'', 84(2): 406--411 (1994), D. Challet and Y.C. Zhang, ``Physica A'', 256:514 (1998)). We view it as an instance of the general problem of how to configure the nodal elements of a distributed dynamical system so that they do not ``work at cross purposes'', in that their collective dynamics avoids frustration and thereby achieves a provided global goal. We summarize a mathematical theory for such configuration applicable when (as in the bar problem) the global goal can be expressed as minimizing a global energy function and the nodes can be expressed as minimizers of local free energy functions. We show that a system designed with that theory performs nearly optimally for the bar problem.Comment: 8 page
    corecore