Zahra Ghafoori

LN-SNE: Log-Normal Distributed Stochastic Neighbor Embedding for Anomaly Detection

Zahra Ghafoori, Sarah M Erfani, James C Bezdek, Shanika Karunasekera, Christopher Leckie

Journal article  |  2020  |  IEEE Transactions on Knowledge and Data Engineering

We present a new unsupervised dimensionality reduction technique, called LN-SNE, for anomaly detection. LN-SNE generates a paramet..

Unsupervised online change point detection in high-dimensional time series

M Zameni, A Sadri, Z Ghafoori, M Moshtaghi, FD Salim, C Leckie, K Ramamohanarao

Journal article  |  2020  |  Knowledge and Information Systems

A critical problem in time series analysis is change point detection, which identifies the times when the underlying distribution ..

Unsupervised and Active Learning Using Maximin-Based Anomaly Detection

Z Ghafoori, JC Bezdek, C Leckie, S Karunasekera

Conference Proceedings  |  2020  |  Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Unsupervised anomaly detection is commonly performed using a distance or density based technique, such as K-Nearest neighbours, Lo..

Deep multi-sphere support vector data description

Zahra Ghafoori, Christopher Leckie

Conference Proceedings  |  2020  |  Proceedings of the 2020 SIAM International Conference on Data Mining, SDM 2020

Deep learning is increasingly used for unsupervised feature extraction and anomaly detection in big datasets. Most deep learning b..

Online K-Means Clustering with Lightweight Coresets

JS Low, Z Ghafoori, C Leckie

Conference Proceedings  |  2019  |  Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Coresets are representative samples of data that can be used to train machine learning models with provable guarantees of approxim..

Seeding on samples for accelerating k-means clustering

JS Low, Z Ghafoori, JC Bezdek, C Leckie

Conference Proceedings  |  2019  |  Proceedings of the 3rd International Conference on Big Data and Internet of Things - BDIOT 2019

K-means clustering with random seeds results in arbitrarily poor clusters. Much work as been done to improve initial centroid sele..

Approximating Dunn's Cluster Validity Indices for Partitions of Big Data

Punit Rathore, Zahra Ghafoori, James C Bezdek, Marimuthu Palaniswami, Christopher Leckie

Journal article  |  2019  |  IEEE Transactions on Cybernetics

Dunn's internal cluster validity index is used to assess partition quality and subsequently identify a "best" crisp partition of n..

Urban Sensing for Anomalous Event Detection: Distinguishing Between Legitimate Traffic Changes and Abnormal Traffic Variability

Masoomeh Zameni, Mengyi He, Masud Moshtaghi, Zahra Ghafoori, Christopher Leckie, James C Bezdek, Kotagiri Ramamohanarao

Conference Proceedings  |  2019  |  Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Sensors deployed in different parts of a city continuously record traffic data, such as vehicle flows and pedestrian counts. We de..

Change Point Detection for Streaming High-Dimensional Time Series

M Zameni, Z Ghafoori, A Sadri, C Leckie, K Ramamohanarao

Conference Proceedings  |  2019  |  Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

© 2019, Springer Nature Switzerland AG. An important task in analysing high-dimensional time series data generated from sensors in..

Dealing with Inliers in Feature Vector Data

Dheeraj Kumar, Zahra Ghafoori, James C Bezdek, Christopher Leckie, Kotagiri Ramamohanarao, Marimuthu Palaniswami

Journal article  |  2018  |  International Journal of Uncertainty Fuzziness and Knowledge-Based Systems

Inliers (bridge points) between clusters degrade the ability of many algorithms to find clusters in numerical data. We present thr..