33 research outputs found

    A hybrid GA–PS–SQP method to solve power system valve-point economic dispatch problems

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    This study presents a new approach based on a hybrid algorithm consisting of Genetic Algorithm (GA), Pattern Search (PS) and Sequential Quadratic Programming (SQP) techniques to solve the well-known power system Economic dispatch problem (ED). GA is the main optimizer of the algorithm, whereas PS and SQP are used to fine tune the results of GA to increase confidence in the solution. For illustrative purposes, the algorithm has been applied to various test systems to assess its effectiveness. Furthermore, convergence characteristics and robustness of the proposed method have been explored through comparison with results reported in literature. The outcome is very encouraging and suggests that the hybrid GA–PS–SQP algorithm is very efficient in solving power system economic dispatch problem

    Exploring Time-Sensitive Variational Bayesian Inference LDA for Social Media Data

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    There is considerable interest among both researchers and the mass public in understanding the topics of discussion on social media as they occur over time. Scholars have thoroughly analysed sampling-based topic modelling approaches for various text corpora including social media; however, another LDA topic modelling implementation—Variational Bayesian (VB)—has not been well studied, despite its known efficiency and its adaptability to the volume and dynamics of social media data. In this paper, we examine the performance of the VB-based topic modelling approach for producing coherent topics, and further, we extend the VB approach by proposing a novel time-sensitive Variational Bayesian implementation, denoted as TVB. Our newly proposed TVB approach incorporates time so as to increase the quality of the generated topics. Using a Twitter dataset covering 8 events, our empirical results show that the coherence of the topics in our TVB model is improved by the integration of time. In particular, through a user study, we find that our TVB approach generates less mixed topics than state-of-the-art topic modelling approaches. Moreover, our proposed TVB approach can more accurately estimate topical trends, making it particularly suitable to assist end-users in tracking emerging topics on social media

    Borehole water level response to barometric pressure as an indicator of aquifer vulnerability

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    The response of borehole water levels to barometric pressure changes in semiconfined aquifers can be used to determine barometric response functions from which aquifer and confining layer properties can be obtained. Following earlier work on barometric response functions and aquifer confinement, we explore the barometric response function as a tool to improve the assessment of groundwater vulnerability in semiconfined aquifers, illustrated through records from two contrasting boreholes in the semiconfined Chalk Aquifer, East Yorkshire, UK. After removal of recharge and Earth tide influences on the water level signal, barometric response functions were estimated and aquifer and confining layer properties determined through an analytical model of borehole water level response to barometric pressure. A link between the thickness and vertical diffusivity of the confining layer determined from the barometric response function, and groundwater vulnerability is proposed. The amplitude spectrum for barometric pressure and instrument resolution favor determination of the barometric response function at frequencies to which confining layer diffusivities are most sensitive. Numerical modeling indicates that while the high frequency response reflects confining layer properties in the immediate vicinity of the borehole, the low frequency response reflects vertical, high diffusivity pathways though the confining layer some hundreds of meters distant. A characteristic time scale parameter, based on vertical diffusivities and thicknesses of the saturated and unsaturated confining layer, is introduced as a measure of semiconfined aquifer vulnerability. The study demonstrates that the barometric response function has potential as a tool for quantitative aquifer vulnerability assessment in semiconfined aquifers

    A systematic review of interactive multimedia interventions to promote children's communication with health professionals: implications for communicating with overweight children

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    Background: Interactive multimedia is an emerging technology that is being used to facilitate interactions between patients and health professionals. The purpose of this review was to identify and evaluate the impact of multimedia interventions (MIs), delivered in the context of paediatric healthcare, in order to inform the development of a MI to promote the communication of dietetic messages with overweight preadolescent children. Of particular interest were the effects of these MIs on child engagement and participation in treatment, and the subsequent effect on health-related treatment outcomes. Methods: An extensive search of 12 bibliographic databases was conducted in April 2012. Studies were included if: one or more child-participant was 7 to 11 years-of-age; a MI was used to improve health-related behaviour; child-participants were diagnosed with a health condition and were receiving treatment for that condition at the time of the study. Data describing study characteristics and intervention effects on communication, satisfaction, knowledge acquisition, changes in self-efficacy, healthcare utilisation, and health outcomes were extracted and summarised using qualitative and quantitative methods. Results: A total of 14 controlled trials, published between 1997 and 2006 met the selection criteria. Several MIs had the capacity to facilitate engagement between the child and a clinician, but only one sought to utilise the MI to improve communication between the child and health professional. In spite of concerns over the quality of some studies and small study populations, MIs were found useful in educating children about their health, and they demonstrated potential to improve children’s health- related self-efficacy, which could make them more able partners in face-to-face communications with health professionals. Conclusions: The findings of this review suggest that MIs have the capacity to support preadolescent child-clinician communication, but further research in this field is needed. Particular attention should be given to designing appropriate MIs that are clinically relevant

    Supplementary Material for: Identifying a Potential Summary Measure for Overall Caries Level in Children Examined with the International Caries Detection and Assessment System

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    <p><b><i>Objective:</i></b> To identify a potential summative summary measure that reflects a patient's overall caries level in children examined with the International Caries Detection and Assessment System (ICDAS). <b><i>Subjects and Methods:</i></b> Participants were 1- to 15-year-old children from Kuwait, Brazil, and Spain. Children's teeth were examined using the ICDAS. Multiple measures of central tendency and dentition-specific indices were considered as potential summative measures. The relationship between the summative measures and number of caries lesions was evaluated considering degrees of caries severity using Spearman's correlation analysis. The results were generated using the Kuwaiti sample and were cross-validated using the Brazilian and Spanish samples. <b><i>Results:</i></b> A total of 2,808 children participated in the present study. Total ICDAS score and mean ICDAS score showed a strong correlation with the number of caries lesions at different caries severity levels in primary, mixed, and permanent dentitions. The total ICDAS score of 51 buccal (B), 61B, 54 occlusal (O), 55O, 64O, 65O, 74O, 75O, 84O, and 85O surfaces in primary dentition and the total ICDAS score of 14O, 16 lingual (L), 16O, 24O, 26L, 26O, 36B, 36O, 37O, 46O, 46B, and 47O surfaces in permanent dentition or mixed dentition (if present) showed strong correlations with the number of caries lesions at different caries severity levels. <b><i>Conclusions:</i></b> Total ICDAS and mean ICDAS scores were the best summary measures of overall caries level at different dental stages. Total ICDAS scores of selectively examined 10 surfaces in primary dentition and 12 surfaces in permanent dentition can give an excellent summary measure for a patient's overall caries level with high diagnostic accuracy.</p
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