Contextual outlier

In addition, the role of contrastive contexts where outliers locate, as well as the relation between outliers and contexts, are usually overlooked in interpretation. Given the fundamental nature of the task, this has been the subject of much research. Recently, a new class of outlier detection algorithms has emerge called contextual outlier detection . An important aspect of an outlier detection technique is the nature of the desired outlier.

Learn more about the different types of outliers : global, contextual , and collective, and why a better grasp of these is key for correct outliers analysis.

A major challenge of contextual outlier detection is identifying the contexts which then allow the identification of outliers. Point outliers are single data points . Hotspot data are obtained by remote sensing using satellite that possibly exist the location information containing irregularities (outliers). For high-dimensional and massive data sets, a relevant subspace based contextual outlier detection algorithm is proposed. Firstly, the relevant subspace, which.

Contextual outliers were detected using . A wide range of methods have been proposed for detect- ing different types of outliers in full space and subspaces. However, the interpretability of outliers , that is, explaining in what ways and to what extent an object is an outlier , remains a critical open issue.

In this paper, we develop a notion of contextual. Three kinds: global, contextual and collective outliers. One object may belong to more than one type of outlier. A data set may have multiple types of outlier. Global outlier (or point anomaly).

An outlier object significantly deviates from the rest of the data set. College of Information Sciences and Technology. Particularly, we develop a notion of multidimensional contextual outliers to model the context of an outlier, and propose a framework for contextual outlier detection. Department of Meteorology and . Intuitively, a contextual outlier is a small group of objects that share strong similarity with a significantly larger reference group of objects on some attributes, but . In our earlier example, a 6-foot tall person is not an outlier in general but a 6-foot tall eight-year-old certainly is.

Mining multidimensional contextual outliers from categorical relational data. A contextual outlier in the tic-tac-toe data set. Example (Motivation 1). Figure shows a contextual outlier found from a data set containing all the 9possible board configurations at the end of tic-tac-toe games.

For details on this data set,. In statistics, an outlier is an observation point that is distant from other observations.

Abstract—The identifying of contextual outliers allows the discovery of anomalous behavior that other forms of outlier detection cannot find. What may appear to be normal behavior with respect to the entire data set can be shown to be anomalous by subsetting the data according to specific spatial or temporal context. Outliers can occur by chance in . In a given data set, a data object is a contextual outlier if it deviates significantly with respect to a specific context of the object. The time contextual outlier measure of the pattern is the fraction of timeslots where the patterns occur the total number of timeslots.

Given a spatio-temporal dataset of STF , and spatial contextual outlier threshold cθ . Spatio-temporal outlier detection plays an important role in some applications fields such as geological disaster monitoring, geophysical exploration, public safety and health etc. For the current lack of contextual outlier detection for spatio-temporal dataset, spatio-temporal outlier detection based on context is . Majority of the existing commercial application for video surveillance system only captures the event frames where the accuracy level of captures is too poor. We reviewed the existing system to find that at present there is no such research technique that offers contextual -based scene identification of outliers.