• Noisy multi-label semi-supervised dimensionality reduction 

      Mikalsen, Karl Øyvind; Soguero-Ruiz, Cristina; Bianchi, Filippo Maria; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)
      Noisy labeled data represent a rich source of information that often are easily accessible and cheap to obtain, but label noise might also have many negative consequences if not accounted for. How to fully utilize noisy labels has been studied extensively within the framework of standard supervised machine learning over a period of several decades. However, very little research has been conducted ...
    • On the Effects of Self-supervision and Contrastive Alignment in Deep Multi-view Clustering 

      Trosten, Daniel Johansen; Løkse, Sigurd Eivindson; Jenssen, Robert; Kampffmeyer, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-22)
      Self-supervised learning is a central component in recent approaches to deep multi-view clustering (MVC). However, we find large variations in the development of self-supervision-based methods for deep MVC, potentially slowing the progress of the field. To address this, we present Deep-MVC, a unified framework for deep MVC that includes many recent methods as instances. We leverage our framework to ...
    • On the Use of Time Series Kernel and Dimensionality Reduction to Identify the Acquisition of Antimicrobial Multidrug Resistance in the Intensive Care Unit 

      Escudero-Arnanz, Oscar; Rodríguez-Álvarez, Joaquín; Mikalsen, Karl Øyvind; Jenssen, Robert; Soguero-Ruiz, Cristina (Conference object; Konferansebidrag, 2021)
      The acquisition of Antimicrobial Multidrug Resistance (AMR) in patients admitted to the Intensive Care Units (ICU) is a major global concern. This study analyses data in the form of multivariate time series (MTS) from 3476 patients recorded at the ICU of University Hospital of Fuenlabrada (Madrid) from 2004 to 2020. 18% of the patients acquired AMR during their stay in the ICU. The goal of ...
    • ProtoVAE: A Trustworthy Self-Explainable Prototypical Variational Model 

      Gautam, Srishti; Boubekki, Ahcene; Hansen, Stine; Salahuddin, Suaiba Amina; Jenssen, Robert; Hohne, Marina Marie-Claire; Kampffmeyer, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-15)
      The need for interpretable models has fostered the development of self-explainable classifiers. Prior approaches are either based on multi-stage optimization schemes, impacting the predictive performance of the model, or produce explanations that are not transparent, trustworthy or do not capture the diversity of the data. To address these shortcomings, we propose ProtoVAE, a variational autoencoder-based ...
    • Ranking Using Transition Probabilities Learned from Multi-Attribute Data 

      Løkse, Sigurd; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-13)
      In this paper, as a novel approach, we learn Markov chain transition probabilities for ranking of multi-attribute data from the inherent structures in the data itself. The procedure is inspired by consensus clustering and exploits a suitable form of the PageRank algorithm. This is very much in the spirit of the original PageRank utilizing the hyperlink structure to learn such probabilities. ...
    • Reconsidering Representation Alignment for Multi-View Clustering 

      Trosten, Daniel Johansen; Løkse, Sigurd Eivindson; Jenssen, Robert; Kampffmeyer, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-13)
      Aligning distributions of view representations is a core component of today’s state of the art models for deep multi-view clustering. However, we identify several drawbacks with naïvely aligning representation distributions. We demonstrate that these drawbacks both lead to less separable clusters in the representation space, and inhibit the model’s ability to prioritize views. Based on these ...
    • Reducing Objective Function Mismatch in Deep Clustering with the Unsupervised Companion Objective 

      Trosten, Daniel Johansen; Jenssen, Robert; Kampffmeyer, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-19)
      Preservation of local similarity structure is a key challenge in deep clustering. Many recent deep clustering methods therefore use autoencoders to help guide the model's neural network towards an embedding which is more reflective of the input space geometry. However, recent work has shown that autoencoder-based deep clustering models can suffer from objective function mismatch (OFM). In order to ...
    • RELAX: Representation Learning Explainability 

      Wickstrøm, Kristoffer; Trosten, Daniel Johansen; Løkse, Sigurd Eivindson; Boubekki, Ahcene; Mikalsen, Karl Øyvind; Kampffmeyer, Michael; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-11)
      Despite the significant improvements that self-supervised representation learning has led to when learning from unlabeled data, no methods have been developed that explain what influences the learned representation. We address this need through our proposed approach, RELAX, which is the first approach for attribution-based explanations of representations. Our approach can also model the uncertainty ...
    • Reservoir computing approaches for representation and classification of multivariate time series 

      Bianchi, Filippo Maria; Scardapane, Simone; Løkse, Sigurd; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-29)
      Classification of multivariate time series (MTS) has been tackled with a large variety of methodologies and applied to a wide range of scenarios. Reservoir computing (RC) provides efficient tools to generate a vectorial, fixed-size representation of the MTS that can be further processed by standard classifiers. Despite their unrivaled training speed, MTS classifiers based on a standard RC ...
    • Robust clustering using a kNN mode seeking ensemble 

      Myhre, Jonas Nordhaug; Mikalsen, Karl Øyvind; Løkse, Sigurd; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-02)
      In this paper we present a new algorithm for parameter-free clustering by mode seeking. Mode seeking, especially in the form of the mean shift algorithm, is a widely used strategy for clustering data, but at the same time prone to poor performance if the parameters are not chosen correctly. We propose to form a <i>clustering ensemble</i> consisting of repeated and bootstrapped runs of the recent kNN ...
    • A Scatter-Based Prototype Framework and Multi-Class Extension of Support Vector Machines 

      Jenssen, Robert; Kloft, Marius; Zien, Alexander; Sonnenburg, Soeren; Müller, Klaus R. (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      We provide a novel interpretation of the dual of support vector machines (SVMs) in terms of scatter with respect to class prototypes and their mean. As a key contribution, we extend this framework to multiple classes, providing a new joint Scatter SVM algorithm, at the level of its binary counterpart in the number of optimization variables. This enables us to implement computationally efficient ...
    • Selective Imputation for Multivariate Time Series Datasets with Missing Values 

      Blazquez-Garcia, Ane; Wickstrøm, Kristoffer Knutsen; Yu, Shujian; Mikalsen, Karl Øyvind; Boubekki, Ahcene; Conde, Angel; Mori, Usue; Jenssen, Robert; Lozano, Jose A. (Journal article; Tidsskriftartikkel, 2023-01-31)
      Multivariate time series often contain missing values for reasons such as failures in data collection mechanisms. Since these missing values can complicate the analysis of time series data, imputation techniques are typically used to deal with this issue. However, the quality of the imputation directly affects the performance of downstream tasks. In this paper, we propose a selective imputation ...
    • Self-Constructing Graph Convolutional Networks for Semantic Labeling 

      Liu, Qinghui; Kampffmeyer, Michael; Jenssen, Robert; Salberg, Arnt-Børre (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-17)
      Graph Neural Networks (GNNs) have received increasing attention in many fields. However, due to the lack of prior graphs, their use for semantic labeling has been limited. Here, we propose a novel architecture called the Self-Constructing Graph (SCG), which makes use of learnable latent variables to generate embeddings and to self-construct the underlying graphs directly from the input features ...
    • Self-constructing graph neural networks to model long-range pixel dependencies for semantic segmentation of remote sensing images 

      Liu, Qinghui; Kampffmeyer, Michael; Jenssen, Robert; Salberg, Arnt Børre (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-16)
      Capturing global contextual representations in remote sensing images by exploiting long-range pixel-pixel dependencies has been shown to improve segmentation performance. However, how to do this efficiently is an open question as current approaches of utilising attention schemes, or very deep models to increase the field of view, increases complexity and memory consumption. Inspired by recent work ...
    • A self-guided anomaly detection-inspired few-shot segmentation network 

      Salahuddin, Suaiba Amina; Hansen, Stine; Gautam, Srishti; Kampffmeyer, Michael; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-13)
      Standard strategies for fully supervised semantic segmentation of medical images require large pixel-level annotated datasets. This makes such methods challenging due to the manual labor required and limits the usability when segmentation is needed for new classes for which data is scarce. Few-shot segmentation (FSS) is a recent and promising direction within the deep learning literature designed ...
    • Semi-supervised target classification in multi-frequency echosounder data 

      Choi, Changkyu; Kampffmeyer, Michael; Handegard, Nils Olav; Salberg, Arnt Børre; Brautaset, Olav; Eikvil, Line; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-12)
      Acoustic target classification in multi-frequency echosounder data is a major interest for the marine ecosystem and fishery management since it can potentially estimate the abundance or biomass of the species. A key problem of current methods is the heavy dependence on the manual categorization of data samples. As a solution, we propose a novel semi-supervised deep learning method leveraging a few ...
    • Short-Term Load Forecasting with Missing Data using Dilated Recurrent Attention Networks 

      Choi, Changkyu; Bianchi, Filippo Maria; Kampffmeyer, Michael; Jenssen, Robert (Conference object; Konferansebidrag, 2020-02-06)
      Forecasting the dynamics of time-varying systems is essential to maintaining the sustainability of the systems. Recent studies have discovered that Recurrent Neural Networks(RNN) applied in the forecasting tasks outperform conventional models that include AutoRegressive Integrated Moving Average(ARIMA). However, due to the structural limitation of vanilla RNN which holds unit-length internal ...
    • Short-Term Load Forecasting with Missing Data using Dilated Recurrent Attention Networks 

      Choi, Changkyu; Bianchi, Filippo Maria; Kampffmeyer, Michael; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-06)
      Forecasting the dynamics of time-varying systems is essential to maintaining the sustainability of the systems. Recent studies have discovered that Recurrent Neural Networks(RNN) applied in the forecasting tasks outperform conventional models that include AutoRegressive Integrated Moving Average(ARIMA). However, due to the structural limitation of vanilla RNN which holds unit-length internal ...
    • Short-Term Load Forecasting with Missing Data using Dilated Recurrent Attention Networks 

      Choi, Changkyu; Kampffmeyer, Michael; Jenssen, Robert (Conference object; Konferansebidrag, 2020)
      Data without annotation are easy to obtain in the real-world, however, established supervised learning methods are not applicable to analyze them. Several learning approaches have been proposed in recent years to exploit the underlying structure of the data without requiring annotations. Semi-supervised learning aims to improve the predictive performance of these unsupervised approaches, by exploiting ...
    • Spectral clustering using PCKID – A probabilistic cluster kernel for incomplete data 

      Løkse, Sigurd; Bianchi, Filippo Maria; Salberg, Arnt-Børre; Jenssen, Robert (Journal article; Tidsskriftartikkel; Manuskript; Peer reviewed; Preprint, 2017-05-19)
      In this paper, we propose <i>PCKID</i>, a novel, robust, kernel function for spectral clustering, specifically designed to handle incomplete data. By combining posterior distributions of Gaussian Mixture Models for incomplete data on different scales, we are able to learn a kernel for incomplete data that does not depend on any critical hyperparameters, unlike the commonly used RBF kernel. To evaluate ...