8,888 research outputs found
Face Alignment Using Boosting and Evolutionary Search
In this paper, we present a face alignment approach using granular features, boosting, and an evolutionary search algorithm. Active Appearance Models (AAM) integrate a shape-texture-combined morphable face model into an efficient fitting strategy, then Boosting Appearance Models (BAM) consider the face alignment problem as a process of maximizing the response from a boosting classifier. Enlightened by AAM and BAM, we present a framework which implements improved boosting classifiers based on more discriminative features and exhaustive search strategies. In this paper, we utilize granular features to replace the conventional rectangular Haar-like features, to improve discriminability, computational efficiency, and a larger search space. At the same time, we adopt the evolutionary search process to solve the deficiency of searching in the large feature space. Finally, we test our approach on a series of challenging data sets, to show the accuracy and efficiency on versatile face images
Learning to Predict with Highly Granular Temporal Data: Estimating individual behavioral profiles with smart meter data
Big spatio-temporal datasets, available through both open and administrative
data sources, offer significant potential for social science research. The
magnitude of the data allows for increased resolution and analysis at
individual level. While there are recent advances in forecasting techniques for
highly granular temporal data, little attention is given to segmenting the time
series and finding homogeneous patterns. In this paper, it is proposed to
estimate behavioral profiles of individuals' activities over time using
Gaussian Process-based models. In particular, the aim is to investigate how
individuals or groups may be clustered according to the model parameters. Such
a Bayesian non-parametric method is then tested by looking at the
predictability of the segments using a combination of models to fit different
parts of the temporal profiles. Model validity is then tested on a set of
holdout data. The dataset consists of half hourly energy consumption records
from smart meters from more than 100,000 households in the UK and covers the
period from 2015 to 2016. The methodological approach developed in the paper
may be easily applied to datasets of similar structure and granularity, for
example social media data, and may lead to improved accuracy in the prediction
of social dynamics and behavior
Claim Models: Granular Forms and Machine Learning Forms
This collection of articles addresses the most modern forms of loss reserving methodology: granular models and machine learning models. New methodologies come with questions about their applicability. These questions are discussed in one article, which focuses on the relative merits of granular and machine learning models. Others illustrate applications with real-world data. The examples include neural networks, which, though well known in some disciplines, have previously been limited in the actuarial literature. This volume expands on that literature, with specific attention to their application to loss reserving. For example, one of the articles introduces the application of neural networks of the gated recurrent unit form to the actuarial literature, whereas another uses a penalized neural network. Neural networks are not the only form of machine learning, and two other papers outline applications of gradient boosting and regression trees respectively. Both articles construct loss reserves at the individual claim level so that these models resemble granular models. One of these articles provides a practical application of the model to claim watching, the action of monitoring claim development and anticipating major features. Such watching can be used as an early warning system or for other administrative purposes. Overall, this volume is an extremely useful addition to the libraries of those working at the loss reserving frontier
Some aspects of the characteristics of vertical screw conveyors for granular material
A theory has been developed, based on a physical model, to describe the behaviour of non-cohesive granular material inside a vertical screw conveyor. By use of this theory, relationships have been derived between dimensionless numbers for capacity, power consumption and efficiency. These relationships, or characteristics, are compared with the results of experiments carried out with two models of vertical screw conveyors, one of 50.8 mm and the other of 162.0 mm diameter. The agreement between the calculated and the measured values of capacity and power consumption was within 5 and 9% respectively.\ud
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The investigation was extended to a screw with an inclined screw blade, because one might expect that this would result in a steeper upward motion of the granules and thus would lead to an increased capacity. It appears, however, that this type of screw has no practical advantages over the normal one, and it is therefore not treated here.\ud
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Two other simpler theories were also developed, one based on a simplified physical model [27] and the other on the conveying of a single granule [28]. It appears that the simpler theories do not agree with the experiment as well as the one developed in this dissertation does, the theory of the single granule producing the greatest discrepancies. With the latter theory, however, the capacity can be reasonably well approximated when the ‘degree of fullness’ 60%.\ud
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The influence of the inlet section on the performance of the screw conveyor is discussed. It was found that the capacity of the conveying section is in most cases limited by the inlet and not by the conveying section itself. As the maximum performance of the conveying section can be calculated with the more developed theory, a method is thus available for judging the potential increase in capacity which could be obtained through improved inlet design
Res2Net: A New Multi-scale Backbone Architecture
Representing features at multiple scales is of great importance for numerous
vision tasks. Recent advances in backbone convolutional neural networks (CNNs)
continually demonstrate stronger multi-scale representation ability, leading to
consistent performance gains on a wide range of applications. However, most
existing methods represent the multi-scale features in a layer-wise manner. In
this paper, we propose a novel building block for CNNs, namely Res2Net, by
constructing hierarchical residual-like connections within one single residual
block. The Res2Net represents multi-scale features at a granular level and
increases the range of receptive fields for each network layer. The proposed
Res2Net block can be plugged into the state-of-the-art backbone CNN models,
e.g., ResNet, ResNeXt, and DLA. We evaluate the Res2Net block on all these
models and demonstrate consistent performance gains over baseline models on
widely-used datasets, e.g., CIFAR-100 and ImageNet. Further ablation studies
and experimental results on representative computer vision tasks, i.e., object
detection, class activation mapping, and salient object detection, further
verify the superiority of the Res2Net over the state-of-the-art baseline
methods. The source code and trained models are available on
https://mmcheng.net/res2net/.Comment: 11 pages, 7 figure
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