396 research outputs found
Statistical methods and neural network approaches for classification of data from multiple sources
Statistical methods for classification of data from multiple data sources are investigated and compared to neural network models. A problem with using conventional multivariate statistical approaches for classification of data of multiple types is in general that a multivariate distribution cannot be assumed for the classes in the data sources. Another common problem with statistical classification methods is that the data sources are not equally reliable. This means that the data sources need to be weighted according to their reliability but most statistical classification methods do not have a mechanism for this. This research focuses on statistical methods which can overcome these problems: a method of statistical multisource analysis and consensus theory. Reliability measures for weighting the data sources in these methods are suggested and investigated. Secondly, this research focuses on neural network models. The neural networks are distribution free since no prior knowledge of the statistical distribution of the data is needed. This is an obvious advantage over most statistical classification methods. The neural networks also automatically take care of the problem involving how much weight each data source should have. On the other hand, their training process is iterative and can take a very long time. Methods to speed up the training procedure are introduced and investigated. Experimental results of classification using both neural network models and statistical methods are given, and the approaches are compared based on these results
Spectral Pattern Recognition by a Two-Layer Perceptron: Effects of Training Set Size
Pattern recognition in urban areas is one of the most challenging issues in
classifying satellite remote sensing data. Parametric pixel-by-pixel classification
algorithms tend to perform poorly in this context. This is because urban areas
comprise a complex spatial assemblage of disparate land cover types - including
built structures, numerous vegetation types, bare soil and water bodies. Thus,
there is a need for more powerful spectral pattern recognition techniques,
utilizing pixel-by-pixel spectral information as the basis for automated urban
land cover detection. This paper adopts the multi-layer perceptron classifier
suggested and implemented in [5]. The objective of this study is to analyse the
performance and stability of this classifier - trained and tested for supervised
classification (8 a priori given land use classes) of a Landsat-5 TM image
(270 x 360 pixels) from the city of Vienna and its northern surroundings
- along with varying the training data set in the single-training-site case.
The performance is measured in terms of total classification, map user's and
map producer's accuracies. In addition, the stability with initial parameter
conditions, classification error matrices, and error curves are analysed in some
detail. (authors' abstract)Series: Discussion Papers of the Institute for Economic Geography and GIScienc
TriResNet: A Deep Triple-stream Residual Network for Histopathology Grading
While microscopic analysis of histopathological slides is generally
considered as the gold standard method for performing cancer diagnosis and
grading, the current method for analysis is extremely time consuming and labour
intensive as it requires pathologists to visually inspect tissue samples in a
detailed fashion for the presence of cancer. As such, there has been
significant recent interest in computer aided diagnosis systems for analysing
histopathological slides for cancer grading to aid pathologists to perform
cancer diagnosis and grading in a more efficient, accurate, and consistent
manner. In this work, we investigate and explore a deep triple-stream residual
network (TriResNet) architecture for the purpose of tile-level histopathology
grading, which is the critical first step to computer-aided whole-slide
histopathology grading. In particular, the design mentality behind the proposed
TriResNet network architecture is to facilitate for the learning of a more
diverse set of quantitative features to better characterize the complex tissue
characteristics found in histopathology samples. Experimental results on two
widely-used computer-aided histopathology benchmark datasets (CAMELYON16
dataset and Invasive Ductal Carcinoma (IDC) dataset) demonstrated that the
proposed TriResNet network architecture was able to achieve noticeably improved
accuracies when compared with two other state-of-the-art deep convolutional
neural network architectures. Based on these promising results, the hope is
that the proposed TriResNet network architecture could become a useful tool to
aiding pathologists increase the consistency, speed, and accuracy of the
histopathology grading process.Comment: 9 page
Population size of Oystercatchers Haematopus ostralegus wintering in Iceland
The first ever survey of Oystercatchers wintering in Iceland found around 11 000 individuals. This is an estimated 30% of the Icelandic population, including juveniles, suggesting that approximately 26 000 Icelandic Oystercatchers migrate to western Europe in the autumn. More Oystercatchers winter in Iceland than at similar latitudes elsewhere in Europe, which may reflect the remoteness and milder winter temperatures on this oceanic island
Belonging to a different landscape: repurposing nationalist affects
This is an article about the embodied, sensual experience of rural landscape as a site where racialized feelings of national belonging get produced. Largely impervious to criticism and reformation by 'thin' legal-political versions of multicultural or cosmopolitan citizenship, it is my suggestion that this racialized belonging is best confronted through the recognition and appreciation of precisely what makes it so compelling. Through an engagement with the theorization of affect in the work of Divya Praful Tolia-Kelly, I consider the resources immanent to the perception of landscapes of national belonging that might be repurposed to unravel that belonging from within. I suggest that forms of environmental consciousness can unpick the mutually reinforcing relationships between nature and nation, opening up opportunities for thinking identity and belonging in different ways, and allowing rural landscapes to become more hospitable places
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Genome-wide trans-ancestry meta-analysis provides insight into the genetic architecture of type 2 diabetes susceptibility.
To further understanding of the genetic basis of type 2 diabetes (T2D) susceptibility, we aggregated published meta-analyses of genome-wide association studies (GWAS), including 26,488 cases and 83,964 controls of European, east Asian, south Asian and Mexican and Mexican American ancestry. We observed a significant excess in the directional consistency of T2D risk alleles across ancestry groups, even at SNPs demonstrating only weak evidence of association. By following up the strongest signals of association from the trans-ethnic meta-analysis in an additional 21,491 cases and 55,647 controls of European ancestry, we identified seven new T2D susceptibility loci. Furthermore, we observed considerable improvements in the fine-mapping resolution of common variant association signals at several T2D susceptibility loci. These observations highlight the benefits of trans-ethnic GWAS for the discovery and characterization of complex trait loci and emphasize an exciting opportunity to extend insight into the genetic architecture and pathogenesis of human diseases across populations of diverse ancestry
Management of asthma in pregnant women by general practitioners: A cross sectional survey
<p>Abstract</p> <p>Background</p> <p>Poorly controlled asthma can lead to maternal and fetal complications. Despite the known risks of poorly controlled asthma during pregnancy and the need for stepping up therapy when appropriate, there are concerns that management is suboptimal in primary care.</p> <p>Our objective was to investigate the management of asthma during pregnancy by general practitioners providing shared maternity care.</p> <p>Methods</p> <p>A pre-piloted, anonymous mail survey was sent to all general practitioners (n = 842) involved in shared maternity care at six maternity hospitals in Victoria, Australia. Respondents were asked about their perceived safety of individual asthma medications during pregnancy. Approach to asthma management during pregnancy was further explored using scenarios of pregnant women with stable and deteriorating asthma and poor medication adherence.</p> <p>Results</p> <p>Inhaled corticosteroids (ICS) were perceived to be the safest and were the preferred preventive medication in first trimester (74.1%), whilst leukotriene receptor antagonists were the least preferred (2.9%). A quarter (25.8%) of respondents would stop or decrease patients' ICS doses during pregnancy, even when their asthma was well controlled by current therapy. In addition, 12.1% of respondents were not sure how to manage deteriorating asthma during pregnancy and opted to refer to another health professional. Almost half the respondents (48.9%) reported encountering medication nonadherence during pregnancy.</p> <p>Conclusion</p> <p>A lack of confidence and/or knowledge among general practitioners in managing deteriorating asthma in pregnancy was observed despite a good understanding of the safety of asthma medications during pregnancy, compliance with evidence-based guidelines in the selection of preventive medications, and self reported good asthma knowledge.</p
New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.
Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes
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