679 research outputs found
Laplacian Mixture Modeling for Network Analysis and Unsupervised Learning on Graphs
Laplacian mixture models identify overlapping regions of influence in
unlabeled graph and network data in a scalable and computationally efficient
way, yielding useful low-dimensional representations. By combining Laplacian
eigenspace and finite mixture modeling methods, they provide probabilistic or
fuzzy dimensionality reductions or domain decompositions for a variety of input
data types, including mixture distributions, feature vectors, and graphs or
networks. Provable optimal recovery using the algorithm is analytically shown
for a nontrivial class of cluster graphs. Heuristic approximations for scalable
high-performance implementations are described and empirically tested.
Connections to PageRank and community detection in network analysis demonstrate
the wide applicability of this approach. The origins of fuzzy spectral methods,
beginning with generalized heat or diffusion equations in physics, are reviewed
and summarized. Comparisons to other dimensionality reduction and clustering
methods for challenging unsupervised machine learning problems are also
discussed.Comment: 13 figures, 35 reference
Ordinal Time Series Analysis with the R Package otsfeatures
[Abstract]: The 21st century has witnessed a growing interest in the analysis of time series data. While most of the literature on the topic deals with real-valued time series, ordinal time series have typically received much less attention. However, the development of specific analytical tools for the latter objects has substantially increased in recent years. The R package otsfeatures attempts to provide a set of simple functions for analyzing ordinal time series. In particular, several commands allowing the extraction of well-known statistical features and the execution of inferential tasks are available for the user. The output of several functions can be employed to perform traditional machine learning tasks including clustering, classification, or outlier detection. otsfeatures also incorporates two datasets of financial time series which were used in the literature for clustering purposes, as well as three interesting synthetic databases. The main properties of the package are described and its use is illustrated through several examples. Researchers from a broad variety of disciplines could benefit from the powerful tools provided by otsfeatures.This research has been supported by the Ministerio de Economía y Competitividad (MINECO) grants MTM2017-82724-R and PID2020-113578RB-100, the Xunta de Galicia (Grupos de Referencia Competitiva ED431C-2020-14), and the Centro de Investigación del Sistema Universitariode Galicia, “CITIC” grant ED431G 2019/01; all of them through the European Regional Development Fund (ERDF).Xunta de Galicia; ED431C-2020-14Xunta de Galicia; ED431G 2019/0
Ordinal time series analysis with the R package otsfeatures
The 21st century has witnessed a growing interest in the analysis of time
series data. Whereas most of the literature on the topic deals with real-valued
time series, ordinal time series have typically received much less attention.
However, the development of specific analytical tools for the latter objects
has substantially increased in recent years. The R package otsfeatures attempts
to provide a set of simple functions for analyzing ordinal time series. In
particular, several commands allowing the extraction of well-known statistical
features and the execution of inferential tasks are available for the user. The
output of several functions can be employed to perform traditional machine
learning tasks including clustering, classification or outlier detection.
otsfeatures also incorporates two datasets of financial time series which were
used in the literature for clustering purposes, as well as three interesting
synthetic databases. The main properties of the package are described and its
use is illustrated through several examples. Researchers from a broad variety
of disciplines could benefit from the powerful tools provided by otsfeatures
Big data analytics for preventive medicine
© 2019, Springer-Verlag London Ltd., part of Springer Nature. Medical data is one of the most rewarding and yet most complicated data to analyze. How can healthcare providers use modern data analytics tools and technologies to analyze and create value from complex data? Data analytics, with its promise to efficiently discover valuable pattern by analyzing large amount of unstructured, heterogeneous, non-standard and incomplete healthcare data. It does not only forecast but also helps in decision making and is increasingly noticed as breakthrough in ongoing advancement with the goal is to improve the quality of patient care and reduces the healthcare cost. The aim of this study is to provide a comprehensive and structured overview of extensive research on the advancement of data analytics methods for disease prevention. This review first introduces disease prevention and its challenges followed by traditional prevention methodologies. We summarize state-of-the-art data analytics algorithms used for classification of disease, clustering (unusually high incidence of a particular disease), anomalies detection (detection of disease) and association as well as their respective advantages, drawbacks and guidelines for selection of specific model followed by discussion on recent development and successful application of disease prevention methods. The article concludes with open research challenges and recommendations
Fault Detection and Diagnosis of Electric Drives Using Intelligent Machine Learning Approaches
Electric motor condition monitoring can detect anomalies in the motor performance which have the potential to result in unexpected failure and financial loss. This study examines different fault detection and diagnosis approaches in induction motors and is presented in six chapters. First, an anomaly technique or outlier detection is applied to increase the accuracy of detecting broken rotor bars. It is shown how the proposed method can significantly improve network reliability by using one-class classification technique. Then, ensemble-based anomaly detection is utilized to compare different methods in ensemble learning in detection of broken rotor bars. Finally, a deep neural network is developed to extract significant features to be used as input parameters of the network. Deep autoencoder is then employed to build an advanced model to make predictions of broken rotor bars and bearing faults occurring in induction motors with a high accuracy
Review of automated time series forecasting pipelines
Time series forecasting is fundamental for various use cases in different
domains such as energy systems and economics. Creating a forecasting model for
a specific use case requires an iterative and complex design process. The
typical design process includes the five sections (1) data pre-processing, (2)
feature engineering, (3) hyperparameter optimization, (4) forecasting method
selection, and (5) forecast ensembling, which are commonly organized in a
pipeline structure. One promising approach to handle the ever-growing demand
for time series forecasts is automating this design process. The present paper,
thus, analyzes the existing literature on automated time series forecasting
pipelines to investigate how to automate the design process of forecasting
models. Thereby, we consider both Automated Machine Learning (AutoML) and
automated statistical forecasting methods in a single forecasting pipeline. For
this purpose, we firstly present and compare the proposed automation methods
for each pipeline section. Secondly, we analyze the automation methods
regarding their interaction, combination, and coverage of the five pipeline
sections. For both, we discuss the literature, identify problems, give
recommendations, and suggest future research. This review reveals that the
majority of papers only cover two or three of the five pipeline sections. We
conclude that future research has to holistically consider the automation of
the forecasting pipeline to enable the large-scale application of time series
forecasting
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