578 research outputs found

    Least squares support vector machine with self-organizing multiple kernel learning and sparsity

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    © 2018 In recent years, least squares support vector machines (LSSVMs) with various kernel functions have been widely used in the field of machine learning. However, the selection of kernel functions is often ignored in practice. In this paper, an improved LSSVM method based on self-organizing multiple kernel learning is proposed for black-box problems. To strengthen the generalization ability of the LSSVM, some appropriate kernel functions are selected and the corresponding model parameters are optimized using a differential evolution algorithm based on an improved mutation strategy. Due to the large computation cost, a sparse selection strategy is developed to extract useful data and remove redundant data without loss of accuracy. To demonstrate the effectiveness of the proposed method, some benchmark problems from the UCI machine learning repository are tested. The results show that the proposed method performs better than other state-of-the-art methods. In addition, to verify the practicability of the proposed method, it is applied to a real-world converter steelmaking process. The results illustrate that the proposed model can precisely predict the molten steel quality and satisfy the actual production demand

    Representing space: the development, content and accuracy of mental representations by the blind and visually impaired

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    This thesis reports on two studies on the perception and cognition of space by individuals who are blind and visually impaired. Research was conducted with students from Dorton College at the Royal London Society for the Blind (RLSB) in Kent. The first experiment examined the content and accuracy of mental representations of a well-known environment. Students walked a route around the RLSB campus and learned the position of ten buildings and structures. They were then asked to make pointing judgments, estimate distances and complete a spatial cued model of the campus. The second experiment considered the wayflnding strategies and spatial coding heuristics used to explore a complex novel environment. Students were asked to explore a maze and learn the position of six different locations. Their search patterns were recorded and analyzed using Geographic Information Systems (GIS) software. Students were tested using the same methods as in the previous experiment and their performance was related to the type and frequency of strategies used during exploration. Results were complemented with a mobility questionnaire, a low vision quality of life questionnaire and data from a literacy and numeracy assessment as well as ethnographic material collected by the author during the two years spent working and living at the RLSB. The thesis begins with a discussion of disability and society framed within the context of geography, urban planning and design. The concepts of blindness and visual impairment are then examined with particular attention given to the psychosocial implications of visual loss. This is followed by a discussion of growth and development, and in-depth review of research on the development, content and accuracy of mental representations by the blind and visually impaired. Finally, the methods used to collect and analyse data for both experiments are considered in light of individual differences and the inadequacy of some statistical techniques to account for the heterogeneous nature of visual impairment. Results from the first experiment revealed significant differences in the accuracy and content of mental representation between the sighted, visually impaired and blind groups for the pointing and model construction tasks. Performance in the distance estimation task was similar across groups. Large individual differences were identified, with the performance of individuals in the same group varying according to the type and requirement of the task. Results from the second experiment also revealed significant differences between the different groups, this time for all three tasks. Here again, large individual differences were found within each group. An analysis of distortions revealed that despite a disparity in accuracy, the blind and visually impaired shared many of the systematic distortions typically found in the mental representation of sighted individuals further confirming their ability develop functional mental representations of space. Performance in the pointing, distance estimation and model construction tasks were also related to the type and frequency of strategies used to explore the maze with the best performers using a combination of egocentric and allocentric strategies. In general, results from the two experiments support the amodal notion that the construction of accurate mental representations of space is not limited to any particular sensory modality but facilitated by the visual system. It also emphasizes the need for mutually supportive techniques that incorporate both quantitative and qualitative methods in the collection and analysis of cognitive data

    Are Place-Based Policies Always a Blessing? Evidence from China’s National Poor County Programme

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    <p>In this paper, we evaluate the effects of a large-scale and continuing place-based policy in China. In 1994, the Chinese central government designated 592 counties as National Poor Counties (NPC), which have been receiving preferential treatment in several aspects. Our identification strategy exploits a discontinuous criterion for determining a county’s eligibility of the programme. We find that the NPC programme failed to foster local economic growth. Further investigation suggests that local capture is partly responsible for this failure. Our findings yield important policy implications that, in countries with limited local accountability, place-based policies characterised by decentralised implementation are not always a blessing.</p

    Subcellular fractionation of brains from 2-month old WT mice.

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    <p>(<b>A</b>) Relative purity of the cytoplasmic (C), membrane (M), nuclear (N), chromatin-bound (nuclear) (Ch) and cytoskeletal (S) fractions were confirmed using the following antibodies: GAPDH (for C), GLT-1 (for M), hnRNP-1 (for N), histone H2A (for Ch), and GFAP (for S). (<b>B</b>) Western blot analysis of dephosphorylated brain fractions obtained from 2-month old WT mice using the tau-specific Tau5 antibody. (<b>C</b>) Relative ratio of the three tau isoforms in the five fractions. (<b>D</b>) Significance analysis using two-way ANOVA. The significance level is calculated by comparing to the cytoplasmic fraction. *, P< 0.05, **, P< 0.01, ***, P< 0.001, and ns, not significant. Error bars represent the standard error of the mean (SEM).</p

    Raising tau isoform-specific antibodies.

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    <p>(<b>A</b>) Schematic representation of the exon structure of the MAPT locus that encodes murine tau. Alternative splicing of exons 2, 3, and 10 generates the three isoforms 0N4R, 1N4R, and 2N4R that are present in the adult murine brain. The scheme shows the location of the epitopes that were used to raise specific antibodies for 0N, 1N and 2N murine tau, as well as for total murine tau (M), without cross-reactivity with human tau. (<b>B</b>) Western blot analysis of RAB-soluble tau extracts obtained from brains of 2-months old wild-type (WT) mice, with stripes probed separately with Tau5, M (total mouse tau) and the murine tau isoform-specific antibodies 01, 2N, and 2N reveals their specificity. Tau knock-out (KO) tissue was included as negative control.</p

    Western blot analysis of dephosphorylated extracts obtained from dissected tissues of 2-month old mice using the Tau5 antibody.

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    <p>(<b>A</b>) Analysis of wild-type (WT) mice; brain (bra), pancreas (pan), liver (liv), kidney (kid), muscle (mus), spleen (spl), testis (tes), and heart (hea). (<b>B</b>) Inclusion of tau knock-out (KO) tissue. Molecular weight and isoforms are indicated. (<b>C</b>) Western blot analysis of dephosphorylated brain extracts from 2-month old, 2-week old and P0 WT mice using the 3R- and 4R-specific antibodies RD3 and RD4, respectively. Note: The relatively intensities of RD3 and RD4 cannot be used to deduce the relative levels of the 3R and 4R isoforms. Instead, the Tau5 pattern is informative.</p

    Western blot analysis of dephosphorylated samples derived from different brain areas of 2-month old WT mice using the Tau5 antibody.

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    <p>(<b>A</b>) Brain tissues: cortex (ctx), hippocampus (hip), pituitary gland (pit), striatum (str), cerebellum (cer) and olfactory bulb (olf). (<b>B</b>) Relative levels of tau isoforms in the different brain areas. (<b>C</b>) Significance analysis using two-way ANOVA. The significance level is calculated by comparing to cortex. *, P< 0.05, **, P< 0.01, ***, P< 0.001, and ns, not significant. Error bars represent the standard error of the mean (SEM).</p

    Expression of murine tau isoforms in the hippocampus of WT mice at day P0.

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    <p>At this stage, 0N (0N3R) is the major isoform. (<b>A</b>-<b>D</b>) Staining with the pan-tau M antibody (<b>A</b>), 0N (<b>B</b>), 1N (<b>C</b>), and 2N (<b>D</b>). (<b>E</b>-<b>H</b>) Counter-staining with Dako tau. Scale bar: 50 μm.</p

    Subcellular fractionation of brains from WT mice at P0.

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    <p>At this stage, 4R isoforms are not expressed. 0N3R is the predominant species, and 2N3R is not detected. (<b>A</b>) Western blot analysis using the same subcellular markers as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084849#pone-0084849-g004" target="_blank">Figure 4</a>. (<b>B</b>) Western blot analysis of dephosphorylated brain fractions obtained from P0 WT mice using Tau5. (<b>C</b>) Relative ratio of the three tau isoforms in the fractions. (<b>D</b>) Significance analysis using two-way ANOVA. </p

    Relative ratio of tau isoforms in five subcellular fractions at P0, 2 weeks and 2 months of age.

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    <p>(<b>A</b>) Cytoplasmic, (<b>B</b>) membrane, (<b>C</b>) soluble nuclear, (<b>D</b>) chromatin-bound, and (<b>E</b>) cytoskeletal fraction. Error bars represent the standard error of the mean (SEM).</p
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