Outlier, or anomaly, detection is essential for optimal performance of machine learning methods and statistical predictive models. It is not just a technical step in a data cleaning process but a key topic in many fields such as fraudulent document detection, in medical applications and assisted diagnosis systems or detecting security threats. In contrast to population-based methods, neighborhood based local approaches are simple flexible methods that have the potential to perform well in small sample size unbalanced problems. However, a main concern of local approaches is the impact that the computation of each sample neighborhood has on the method performance. Most approaches use a distance in the feature space to define a single neighborhood that requires careful selection of several parameters. This work presents a local approach based on a local measure of the heterogeneity of sample labels in the feature space considered as a topological manifold. Topology is computed using the communities of a weighted graph codifying mutual nearest neighbors in the feature space. This way, we provide with a set of multiple neighborhoods able to describe the structure of complex spaces without parameter fine tuning. The extensive experiments on real-world data sets show that our approach overall outperforms, both, local and global strategies in multi and single view settings.
IBM Research（IBM研究院）；Indian Institute of Science（印度科学院）
Network (or graph) embedding is the task to map the nodes of a graph to a lower dimensional vector space, such that it preserves the graph properties and facilitates the downstream network mining tasks. Real world networks often come with (community) outlier nodes, which behave differently from the regular nodes of the community. These outlier nodes can affect the embedding of the regular nodes, if not handled carefully. In this paper, we propose a novel unsupervised graph embedding approach (called DMGD) which integrates outlier and community detection with node embedding. We extend the idea …
University of Adelaide（阿德莱德大学）；University of Technology Sydney（悉尼科技大学）
Anomaly detection, a.k.a. outlier detection or novelty detection, has been a lasting yet active research area in various research communities for several decades. There are still some unique problem complexities and challenges that require advanced approaches. In recent years, deep learning enabled anomaly detection, i.e., deep anomaly detection, has emerged as a critical direction. This paper surveys the research of deep anomaly detection with a comprehensive taxonomy, covering advancements in three high-level categories and 11 fine-grained categories of the methods. We review their key intui…
BMW Group（宝马集团）；Johannes Kepler University Linz（林茨约翰内斯·开普勒大学）；University of Applied Sciences Upper Austria（上奥地利应用科学大学）；University of Auckland（奥克兰大学）
OutlierDetection.jl is an open-source ecosystem for outlier detection in Julia. It provides a range of high-performance outlier detection algorithms implemented directly in Julia. In contrast to previous packages, our ecosystem enables the development highly-scalable outlier detection algorithms using a high-level programming language. Additionally, it provides a standardized, yet flexible, interface for future outlier detection algorithms and allows for model composition unseen in previous packages. Best practices such as unit testing, continuous integration, and code coverage reporting are e…
Laboratoire des Signaux et Systèmes (L2S)（信号与系统实验室）；CentraleSupélec-CNRS-Université Paris-Sud（巴黎中央理工-高等电力学院-法国国家科学研究中心-巴黎第十一大学）；Université Paris-Saclay（巴黎萨克雷大学）；Instituto de Cálculo（计算研究所）；Universidad de Buenos Aires（布宜诺斯艾利斯大学）；IMAS-CONICET（阿根廷国家科学技术研究委员会数学应用研究所）
Though very popular, it is well known that the EM for GMM algorithm suffers from non-Gaussian distribution shapes, outliers and high-dimensionality. In this paper, we design a new robust clustering algorithm that can efficiently deal with noise and outliers in diverse data sets. As an EM-like algorithm, it is based on both estimations of clusters centers and covariances. In addition, using a semi-parametric paradigm, the method estimates an unknown scale parameter per data-point. This allows the algorithm to accommodate for heavier tails distributions and outliers without significantly loosing…
TU Dortmund University（多特蒙德工业大学）；Research Center Trustworthy Data Science and Security（可信数据科学与安全研究中心）
Data cubes are multidimensional databases, often built from several separate databases, that serve as flexible basis for data analysis. Surprisingly, outlier detection on data cubes has not yet been treated extensively. In this work, we provide the first framework to evaluate robust outlier detection methods in data cubes (RODD). We introduce a novel random forest-based outlier detection approach (RODD-RF) and compare it with more traditional methods based on robust location estimators. We propose a general type of test data and examine all methods in a simulation study. Moreover, we apply ROO…
CityLearn v2: Energy-flexible, resilient, occupant-centric, and carbon-aware management of grid-interactive communities
The University of Texas at Austin（得克萨斯大学奥斯汀分校）；Concordia University（康考迪亚大学）；Politecnico di Torino（都灵理工大学）；Polytechnic of Porto（波尔图理工学院）；PassiveLogic（帕西夫逻辑公司）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
Pohang University of Science and Technology（浦项科技大学）；Center for Complex Networks and Systems Research（复杂网络与系统研究中心）；Luddy School of Informatics, Computing, and Engineering, Indiana University（印第安纳大学勒迪信息、计算与工程学院）
Graph embedding techniques, which learn low-dimensional representations of a graph, are achieving state-of-the-art performance in many graph mining tasks. Most existing embedding algorithms assign a single vector to each node, implicitly assuming that a single representation is enough to capture all characteristics of the node. However, across many domains, it is common to observe pervasively overlapping community structure, where most nodes belong to multiple communities, playing different roles depending on the contexts. Here, we propose persona2vec, a graph embedding framework that efficien…
MERLIN: Multi-agent offline and transfer learning for occupant-centric energy flexible operation of grid-interactive communities using smart meter data and CityLearn
The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Electric Power Research Institute（电力科学研究院）
Robust Conformal Outlier Detection under Contaminated Reference Data
Department of Electrical and Computer Engineering, Technion IIT, Haifa, Israel（技术学院电子与计算机工程系）；Department of Computer Science, Technion IIT, Haifa, Israel（技术学院计算机科学系）；Department of Data Sciences and Operations, University of Southern California, Los Angeles, California, USA（南加州大学数据科学与运营系）；Department of Computer Science, University of Southern California, Los Angeles, California, USA（南加州大学计算机科学系）
Community Search (CS) is one of the fundamental tasks in network science and has attracted much attention due to its ability to discover personalized communities with a wide range of applications. Given any query nodes, CS seeks to find a densely connected subgraph containing query nodes. Most existing approaches usually study networks with a single type of proximity between nodes, which defines a single view of a network. However, in many applications such as biological, social, and transportation networks, interactions between objects span multiple aspects, yielding networks with multiple vi…
Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences（中国科学院机器人与智能制造创新研究院）；University of Chinese Academy of Sciences（中国科学院大学）；Northeastern University（东北大学）；Xidian University（西安电子科技大学）；Huaqiao University（华侨大学）
Consider the lifelong machine learning paradigm whose objective is to learn a sequence of tasks depending on previous experiences, e.g., knowledge library or deep network weights. However, the knowledge libraries or deep networks for most recent lifelong learning models are with prescribed size, and can degenerate the performance for both learned tasks and coming ones when facing with a new task environment (cluster). To address this challenge, we propose a novel incremental clustered lifelong learning framework with two knowledge libraries: feature learning library and model knowledge library…
Searching for local communities is an important research challenge that allows for personalized community discovery and supports advanced data analysis in various complex networks, such as the World Wide Web, social networks, and brain networks. The evolution of these networks over time has motivated several recent studies to identify local communities in temporal networks. Given any query nodes, Community Search aims to find a densely connected subgraph containing query nodes. However, existing community search approaches in temporal networks have two main limitations: (1) they adopt pre-defi…
National Taiwan University（台湾大学）；Mila-Quebec Institute for Learning Algorithms（Mila-魁北克学习算法研究所）；Harvard University（哈佛大学）；Element AI；HEC Montreal（蒙特利尔高等商学院）
This paper focuses on two fundamental tasks of graph analysis: community detection and node representation learning, which capture the global and local structures of graphs, respectively. In the current literature, these two tasks are usually independently studied while they are actually highly correlated. We propose a probabilistic generative model called vGraph to learn community membership and node representation collaboratively. Specifically, we assume that each node can be represented as a mixture of communities, and each community is defined as a multinomial distribution over nodes. Both…
FiMReSt: Finite Mixture of Multivariate Regulated Skew-t Kernels -- A Flexible Probabilistic Model for Multi-Clustered Data with Asymmetrically-Scattered Non-Gaussian Kernels
Tandon School of Engineering, New York University（纽约大学坦登工程学院）；NYU WIRELESS（纽约大学无线研究中心）；NYU CUSP（纽约大学城市科学与进步中心）
Clustering is an effective technique in data mining to group a set of objects in terms of some attributes. Among various clustering approaches, the family of K-Means algorithms gains popularity due to simplicity and efficiency. However, most of existing K-Means based clustering algorithms cannot deal with outliers well and are difficult to efficiently solve the problem embedded the $L_0$-norm constraint. To address the above issues and improve the performance of clustering significantly, we propose a novel clustering algorithm, named REFCMFS, which develops a $L_{2,1}$-norm robust loss as the …
Shenzhen Institute of Computing Sciences, Shenzhen University（深圳大学深圳计算科学研究院）；Osaka University（大阪大学）；Nagoya University（名古屋大学）；Dongguan University of Technology（东莞理工学院）；University of New South Wales（新南威尔士大学）
Selectivity estimation aims at estimating the number of database objects that satisfy a selection criterion. Answering this problem accurately and efficiently is essential to many applications, such as density estimation, outlier detection, query optimization, and data integration. The estimation problem is especially challenging for large-scale high-dimensional data due to the curse of dimensionality, the large variance of selectivity across different queries, and the need to make the estimator consistent (i.e., the selectivity is non-decreasing in the threshold). We propose a new deep learni…
Paradigm（第四范式）；Universitat de Barcelona（巴塞罗那大学）；Computer Vision Center（计算机视觉中心）；LISN/CNRS/INRIA, Univ. Paris-Saclay（巴黎萨克雷大学LISN实验室/法国国家科学研究中心/法国国家信息与自动化研究所）；ChaLearn（ChaLearn挑战赛组织）；Univ. Grenoble Alpes/CNRS（格勒诺布尔阿尔卑斯大学/法国国家科学研究中心）；Tsinghua University（清华大学）
Obtaining standardized crowdsourced benchmark of computational methods is a major issue in data science communities. Dedicated frameworks enabling fair benchmarking in a unified environment are yet to be developed. Here we introduce Codabench, an open-source, community-driven platform for benchmarking algorithms or software agents versus datasets or tasks. A public instance of Codabench (https://www.codabench.org/) is open to everyone, free of charge, and allows benchmark organizers to compare fairly submissions, under the same setting (software, hardware, data, algorithms), with custom protoc…
Shanghai Jiao Tong University（上海交通大学）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；University of the Chinese Academy of Sciences（中国科学院大学）；Key Lab for Astrophysics（天体物理重点实验室）
The Gaussian process (GP) regression can be severely biased when the data are contaminated by outliers. This paper presents a new robust GP regression algorithm that iteratively trims the most extreme data points. While the new algorithm retains the attractive properties of the standard GP as a nonparametric and flexible regression method, it can greatly improve the model accuracy for contaminated data even in the presence of extreme or abundant outliers. It is also easier to implement compared with previous robust GP variants that rely on approximate inference. Applied to a wide range of expe…
