Comparative Study on Trajectory Outlier Detection Algorithms

2019 ◽  
Author(s):  
Asma Belhadi ◽  
Youcef Djenouri ◽  
Jerry Chun-Wei Lin
Keyword(s):  
Comparative Study ◽  
Outlier Detection ◽  
Detection Algorithms ◽  
Trajectory Outlier Detection

Trajectory Outlier Detection

2021 ◽  
Vol 15 (2) ◽  
pp. 1-28
Author(s):  
Youcef Djenouri ◽  
Djamel Djenouri ◽  
Jerry Chun-Wei Lin
Keyword(s):  
Outlier Detection ◽  
High Performance ◽  
Graphic Processing Units ◽  
Two Phase ◽  
K Nearest Neighbors ◽  
Sliding Windows ◽  
Detection Algorithms ◽  
Pruning Strategy ◽  
Trajectory Outlier Detection ◽  
The Individual

This article introduces two new problems related to trajectory outlier detection: (1) group trajectory outlier (GTO) detection and (2) deviation point detection for both individual and group of trajectory outliers. Five algorithms are proposed for the first problem by adapting DBSCAN , k nearest neighbors (kNN) , and feature selection (FS) . DBSCAN-GTO first applies DBSCAN to derive the micro clusters , which are considered as potential candidates. A pruning strategy based on density computation measure is then suggested to find the group of trajectory outliers. kNN-GTO recursively derives the trajectory candidates from the individual trajectory outliers and prunes them based on their density. The overall process is repeated for all individual trajectory outliers. FS-GTO considers the set of individual trajectory outliers as the set of all features, while the FS process is used to retrieve the group of trajectory outliers. The proposed algorithms are improved by incorporating ensemble learning and high-performance computing during the detection process. Moreover, we propose a general two-phase-based algorithm for detecting the deviation points, as well as a version for graphic processing units implementation using sliding windows. Experiments on a real trajectory dataset have been carried out to demonstrate the performance of the proposed approaches. The results show that they can efficiently identify useful patterns represented by group of trajectory outliers, deviation points, and that they outperform the baseline group detection algorithms.

scholarly journals Outlier Detection Algorithms Over Fuzzy Data with Weighted Least Squares

2021 ◽  
Author(s):  
Natalia Nikolova ◽  
Rosa M. Rodríguez ◽  
Mark Symes ◽  
Daniela Toneva ◽  
Krasimir Kolev ◽  
...  
Keyword(s):  
Least Squares ◽  
Outlier Detection ◽  
Weighted Least Squares ◽  
Fuzzy Data ◽  
Detection Algorithms

scholarly journals Outlier Detection Methods for Uncovering of Critical Events in Historical Phasor Measurement Records

2018 ◽  
Vol 64 ◽  
pp. 08006 ◽  
Author(s):  
Kummerow André ◽  
Nicolai Steffen ◽  
Bretschneider Peter
Keyword(s):  
Power Systems ◽  
Outlier Detection ◽  
Training Data ◽  
Detection Methods ◽  
Data Sets ◽  
Critical Events ◽  
Failure Patterns ◽  
Detection Algorithms ◽  
Reduction Techniques ◽  
Dimension Reduction Techniques

The scope of this survey is the uncovering of potential critical events from mixed PMU data sets. An unsupervised procedure is introduced with the use of different outlier detection methods. For that, different techniques for signal analysis are used to generate features in time and frequency domain as well as linear and non-linear dimension reduction techniques. That approach enables the exploration of critical grid dynamics in power systems without prior knowledge about existing failure patterns. Furthermore new failure patterns can be extracted for the creation of training data sets used for online detection algorithms.

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