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4387130173 · May 202619922001200920172026
48 results for outlier scores

Transforms distance-based outlier scores into interpretable probabilistic estimates.

problem Difficult interpretation of distance-based outlier scores.
method Generic transformation of scores into probabilistic estimates using distance probability distributions.
result Probabilistic transformation improves interpretability without impacting detection performance.

Two new outlyingness scores improve outlier detection in high-dimensional data.

problem Detecting outliers in high-dimensional data with varying cluster shapes and intensities.
method Outlyingness scores (OOS and IOS) based on Cluster Catch Digraphs (CCDs).
result Both OOS and IOS outperform CCD-based methods in identifying global and local outliers, especially IOS.

We describe a formal approach to identify 'root causes' of outliers observed in nn variables X1,,XnX_1,\dots,X_n in a scenario where the causal relation between the variables is a known directed acyclic graph (DAG). To this end, we first introduce a systematic way to define outlier scores. Further, we introduce the concep…

2019-12-05abs ↗pdf ↗

Outlier detection amounts to finding data points that differ significantly from the norm. Classic outlier detection methods are largely designed for single data type such as continuous or discrete. However, real world data is increasingly heterogeneous, where a data point can have both discrete and continuous attribute…

2016-08-17abs ↗pdf ↗

Outlier detection aims to identify unusual data instances that deviate from expected patterns. The outlier detection is particularly challenging when outliers are context dependent and when they are defined by unusual combinations of multiple outcome variable values. In this paper, we develop and study a new conditiona…

2015-05-15abs ↗pdf ↗

EHBOS enhances HBOS by capturing feature interactions, improving anomaly detection.

problem Limited ability of HBOS to detect anomalies in datasets with feature interactions.
method Incorporates two-dimensional histograms to capture feature pair dependencies.
result EHBOS outperforms HBOS on datasets with critical feature interactions, achieving notable improvements in ROC AUC.

We present a novel notion of outlier, called the Concentration Free Outlier Factor, or CFOF. As a main contribution, we formalize the notion of concentration of outlier scores and theoretically prove that CFOF does not concentrate in the Euclidean space for any arbitrary large dimensionality. To the best of our knowled…

2019-01-14abs ↗pdf ↗

Selecting and combining the outlier scores of different base detectors used within outlier ensembles can be quite challenging in the absence of ground truth. In this paper, an unsupervised outlier detector combination framework called DCSO is proposed, demonstrated and assessed for the dynamic selection of most compete…

2019-11-23abs ↗pdf ↗

High-dimensional data poses unique challenges in outlier detection process. Most of the existing algorithms fail to properly address the issues stemming from a large number of features. In particular, outlier detection algorithms perform poorly on data set of small size with a large number of features. In this paper, w…

2019-09-09abs ↗pdf ↗

SDCOR clusters massive datasets efficiently, detecting outliers with low memory usage.

problem Local outlier detection in large-scale datasets.
method Chunk-based density clustering with incremental updates.
result SDCOR achieves lower linear time complexity and better efficiency than traditional methods.

Paper proposes a scoring function for detecting anomalies in large datasets.

problem Detecting outliers in large, feature-rich datasets.
method Binary classification problem with a two-sample linear rank statistic.
result Empirical results show the effectiveness of the proposed scoring function.

Proposes GMOTE for better handling imbalanced data.

problem Classification of imbalanced data.
method Generates minority class instances using Gaussian Mixture Model, considering outliers through Mahalanobis distance.
result Shows better accuracy and F1-Score when combined with CART or SVM.

Outlier detection plays an essential role in many data-driven applications to identify isolated instances that are different from the majority. While many statistical learning and data mining techniques have been used for developing more effective outlier detection algorithms, the interpretation of detected outliers do…

2017-11-28abs ↗pdf ↗

Rare data in a large-scale database are called outliers that reveal significant information in the real world. The subspace-based outlier detection is regarded as a feasible approach in very high dimensional space. However, the outliers found in subspaces are only part of the true outliers in high dimensional space, in…

2014-05-05abs ↗pdf ↗

This paper presents a simple but effective density-based outlier detection approach with the local kernel density estimation (KDE). A Relative Density-based Outlier Score (RDOS) is introduced to measure the local outlierness of objects, in which the density distribution at the location of an object is estimated with a …

2016-06-28abs ↗pdf ↗

Feature selection places an important role in improving the performance of outlier detection, especially for noisy data. Existing methods usually perform feature selection and outlier scoring separately, which would select feature subsets that may not optimally serve for outlier detection, leading to unsatisfying perfo…

2020-01-15abs ↗pdf ↗

MMDCP improves outlier detection and classification with adaptive prediction sets.

problem Label shift and distribution differences in multi-class settings.
method Combines distance measures with full conformal prediction for adaptive prediction sets.
result Valid coverage and effective control of class-wise false discovery rate (CW-FDR).

Integrates outlier detection into neural networks for improved performance.

problem Lack of competency awareness in machine learning systems, especially in detecting outliers.
method Null Space Analysis (NuSA) of neural networks, computing and controlling null space projection.
result NuSA-trained networks maintain classification performance and detect outliers effectively.

Outlier detection (also known as anomaly detection or deviation detection) is a process of detecting data points in which their patterns deviate significantly from others. It is common to have outliers in industry applications, which could be generated by different causes such as human error, fraudulent activities, or …

2019-11-05abs ↗pdf ↗

UN-AVOIDS visualizes and detects anomalies without needing labeled data.

problem The need for a unified framework to visualize and detect anomalies.
method UN-AVOIDS is an unsupervised, nonparametric approach that transforms data into a new space (NCDF) for both visualization and detection.
result UN-AVOIDS assigns invariant anomalous scores and achieves high AUC in detecting anomalies.

Often the challenge associated with tasks like fraud and spam detection[1] is the lack of all likely patterns needed to train suitable supervised learning models. In order to overcome this limitation, such tasks are attempted as outlier or anomaly detection tasks. We also hypothesize that out- liers have behavioral pat…

2017-12-12abs ↗pdf ↗

NLR models often perform worse than LR for outlying input data in environmental sciences.

problem NLR models often give poor predictions for input data outside the training domain.
method Screened input data for outliers, using linear extrapolation for outliers based on NLR within the non-outlier domain.
result NLROR_{\mathrm{OR}} approach reduces poor extrapolation and tends to outperform NLR and LR for outliers.

This paper investigates differentially private analysis of distance-based outliers. The problem of outlier detection is to find a small number of instances that are apparently distant from the remaining instances. On the other hand, the objective of differential privacy is to conceal presence (or absence) of any partic…

2015-07-24abs ↗pdf ↗

A novel framework IMBoost improves outlier detection by leveraging the inlier memorization effect.

problem Challenges in unsupervised outlier detection, especially when inliers and outliers are not well-separated or form dense clusters.
method IMBoost framework that incorporates active learning to selectively acquire informative labels and explicitly reinforce the inlier memorization effect.
result IMBoost significantly outperforms state-of-the-art active outlier detection methods and requires less computational cost.

ECOD detects outliers without parameters, fast and simple.

problem Detecting outliers in large, high-dimensional datasets efficiently and interpretably.
method ECOD estimates empirical cumulative distribution functions per dimension, then computes tail probabilities and outlier scores.
result ECOD outperforms state-of-the-art methods in accuracy, efficiency, and scalability.

Study improves data quality assessment for structural monitoring data.

problem Ensuring reliability of structural health monitoring data.
method Probabilistic data quality assessment using a conditional diffusion model.
result Significantly improves accuracy of data quality assessment.

Outlier detection methods have become increasingly relevant in recent years due to increased security concerns and because of its vast application to different fields. Recently, Pauwels and Lasserre (2016) noticed that the sublevel sets of the inverse Christoffel function accurately depict the shape of a cloud of data …

2018-06-18abs ↗pdf ↗