scholarly journals Event detection in time series by genetic programming

2012 ◽  
Author(s):  
Feng Xie ◽  
Andy Song ◽  
Vic Ciesielski
Keyword(s):  
Time Series ◽  
Genetic Programming ◽  
Event Detection

scholarly journals Time series prediction using a recursive algorithm of a combination of genetic programming and constant optimization

2002 ◽  
Vol 15 (2) ◽  
pp. 265-279 ◽  
Author(s):  
Witthaya Panyaworayan ◽  
Georg Wuetschner
Keyword(s):  
Time Series ◽  
Genetic Programming ◽  
Recursive Algorithm ◽  
Time Series Prediction ◽  
Prediction Function ◽  
Prediction Functions

In this paper we present a prediction process of Time Series using a combination of Genetic Programming and Constant Optimization. The Genetic Programming will be used to evolve the structure of the prediction function, whereas the Constant Optimization will determine the numerical parameters of the prediction function. The prediction process is applied recursively. In each recursion step, a sub-prediction function is evolved. At the end of the iteration all sub-prediction functions form the final prediction function. The avoiding of a major problem in the prediction called over-fitting is also described in this article.

Combing empirical matched field processing at IMS station SPITS and convolutional neural networks for calving event detection in Svalbard

2021 ◽  
Author(s):  
Andreas Köhler ◽  
Steffen Mæland
Keyword(s):  
Machine Learning ◽  
Neural Networks ◽  
Time Series ◽  
Convolutional Neural Networks ◽  
Event Detection ◽  
The Arctic ◽  
Beam Power ◽  
Seismic Events ◽  
Tidewater Glaciers ◽  
Seismic Arrays

<p>We combine the empirical matched field (EMF) method and machine learning using Convolutional Neural Networks (CNNs) for calving event detection at the IMS station SPITS and GSN station KBS on the Arctic Archipelago of Svalbard. EMF detection with seismic arrays seeks to identify all signals similar to a single template generated by seismic events in a confined target region. In contrast to master event cross-correlation detectors, the detection statistic is not the waveform similarity, but the array beam power obtained using empirical phase delays (steering parameters) between the array stations. Unlike common delay-and-sum beamforming, the steering parameters do not need to represent a plane wave and are directly computed from the template signal without assuming a particular apparent velocity and back-azimuth. As for all detectors, the false alarms rate depends strongly on the beam power threshold setting and therefore needs appropriate tuning or alternatively post-processing. Here, we combine the EMF detector using a low detection threshold with a post-detection classification step. The classifier uses spectrograms of single-station three-component records and state-of-the-art CNNs pre-trained for image recognition. Spectrograms of three-component seismic data are hereby combined as RGB images. We apply the methodology to detect calving events at tidewater glaciers in the Kongsfjord region in Northwestern Svalbard. The EMF detector uses data of the SPITS array, at about 100 km distance to the glaciers, while the CNN classifier processes data from the single three-component station KBS at 15 km distance using time windows where the event is expected according to the EMF detection. The EMF detector combines templates for the P and for the S wave onsets of a confirmed, large calving event. The CNN spectrogram classifier is trained using classes of confirmed calving signals from four different glaciers in the Kongsfjord region, seismic noise examples, and regional tectonic seismic events. By splitting the data into training and test data set, the CNN classifier yields a recognition rate of 89% on average. This is encouragingly high given the complex nature of calving signals and their visually similar waveforms. Subsequently, we process continuous data of 6 months in 2016 using the EMF-CNN method to produce a time series of glacier calving. About 90% of the confirmed calving signals used for the CNN training are detected by EMF processing, and around 80% are assigned to the correct glacier after CNN classification. Such calving time series allow us to estimate and monitor ice loss at tidewater glaciers which in turn can help to better understand the impact of climate change in Polar regions. Combining the superior detection capability of (less common) seismic arrays at a larger source distance with a powerful machine learning classifier at single three-component stations closer to the source, is a promising approach not only for environmental monitoring, but also for event detection and classification in a CTBTO verification context.</p>

Using Genetic Programming to Extract Knowledge from Artificial Neural Networks

2008 ◽  
pp. 308-327
Author(s):  
Daniel Rivero ◽  
Miguel Varela ◽  
Javier Pereira
Keyword(s):  
Neural Networks ◽  
Time Series ◽  
Artificial Neural Networks ◽  
Genetic Programming ◽  
Recurrent Neural Networks ◽  
Know How ◽  
Artificial Neural

A technique is described in this chapter that makes it possible to extract the knowledge held by previously trained artificial neural networks. This makes it possible for them to be used in a number of areas (such as medicine) where it is necessary to know how they work, as well as having a network that functions. This chapter explains how to carry out this process to extract knowledge, defined as rules. Special emphasis is placed on extracting knowledge from recurrent neural networks, in particular when applied in predicting time series.

scholarly journals Enhanced Heartbeat Graph for emerging event detection on Twitter using time series networks

2019 ◽  
Vol 136 ◽  
pp. 115-132 ◽  
Author(s):  
Zafar Saeed ◽  
Rabeeh Ayaz Abbasi ◽  
Imran Razzak ◽  
Onaiza Maqbool ◽  
Abida Sadaf ◽  
...  
Keyword(s):  
Time Series ◽  
Event Detection
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