publications

journal and conference publications

I have published more than 100 papers in international conferences (CVPR, ICCV, ECCV, ICPR, ISCAS, ...) and international journals (TNNLS, TKDE, PR, ...). You can find a list of my publications, along with links to the paper/publisher site and code (when available) below. If you find any broken link or missing paper, please let me know and I will be happy to share our work with you.

Journals

2021

  1. deepsing: Generating sentiment-aware visual stories using cross-modal music translation
    Passalis, Nikolaos, and Doropoulos, Stavros
    Expert Systems with Applications 2021
  2. Deep supervised hashing using quadratic spherical mutual information for efficient image retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    Signal Processing: Image Communication 2021
  3. Forecasting Financial Time Series Using Robust Deep Adaptive Input Normalization
    Journal of Signal Processing Systems 2021
  4. Diversity-driven knowledge distillation for financial trading using Deep Reinforcement Learning
    Tsantekidis, Avraam, Passalis, Nikolaos, and Tefas, Anastasios
    Neural Networks 2021
  5. Improving knowledge distillation using unified ensembles of specialized teachers
    Zaras, Adamantios, Passalis, Nikolaos, and Tefas, Anastasios
    Pattern Recognition Letters 2021
  6. Online Subclass Knowledge Distillation
    Tzelepi, Maria, Passalis, Nikolaos, and Tefas, Anastasios
    Expert Systems with Applications 2021

2020

  1. Using deep learning for price prediction by exploiting stationary limit order book features
    Tsantekidis, Avraam, Passalis, Nikolaos, Tefas, Anastasios, Kanniainen, Juho, Gabbouj, Moncef, and Iosifidis, Alexandros
    Applied Soft Computing 2020
  2. Temporal logistic neural bag-of-features for financial time series forecasting leveraging limit order book data
    Pattern Recognition Letters 2020
  3. Bag of color features for color constancy
    Laakom, Firas, Passalis, Nikolaos, Raitoharju, Jenni, Nikkanen, Jarno, Tefas, Anastasios, Iosifidis, Alexandros, and Gabbouj, Moncef
    IEEE Transactions on Image Processing 2020
  4. Variance-preserving deep metric learning for content-based image retrieval
    Pattern Recognition Letters 2020
  5. Femtojoule per MAC neuromorphic photonics: an energy and technology roadmap
    Totović, Angelina R, Dabos, George, Passalis, Nikolaos, Tefas, Anastasios, and Pleros, Nikos
    IEEE Journal of Selected Topics in Quantum Electronics 2020
  6. Hypersphere-based weight imprinting for few-shot learning on embedded devices
    IEEE Transactions on Neural Networks and Learning Systems 2020
  7. Recurrent bag-of-features for visual information analysis
    Krestenitis, Marios, Passalis, Nikolaos, Iosifidis, Alexandros, Gabbouj, Moncef, and Tefas, Anastasios
    Pattern Recognition 2020
  8. Efficient adaptive inference for deep convolutional neural networks using hierarchical early exits
    Passalis, Nikolaos, Raitoharju, Jenni, Tefas, Anastasios, and Gabbouj, Moncef
    Pattern Recognition 2020
  9. All-optical WDM recurrent neural networks with gating
    Mourgias-Alexandris, George, Dabos, George, Passalis, Nikolaos, Totović, Angelina, Tefas, Anastasios, and Pleros, Nikos
    IEEE Journal of Selected Topics in Quantum Electronics 2020
  10. Initializing photonic feed-forward neural networks using auxiliary tasks
    Passalis, Nikolaos, Mourgias-Alexandris, George, Pleros, Nikos, and Tefas, Anastasios
    Neural Networks 2020
  11. Probabilistic knowledge transfer for lightweight deep representation learning
    Passalis, Nikolaos, Tzelepi, Maria, and Tefas, Anastasios
    IEEE Transactions on Neural Networks and Learning Systems 2020
  12. Price trailing for financial trading using deep reinforcement learning
    Tsantekidis, Avraam, Passalis, Nikolaos, Toufa, Anastasia-Sotiria, Saitas-Zarkias, Konstantinos, Chairistanidis, Stergios, and Tefas, Anastasios
    IEEE Transactions on Neural Networks and Learning Systems 2020
  13. Multi-Level Reversible Data Anonymization via Compressive Sensing and Data Hiding
    Yamac, Mehmet, Ahishali, Mete, Passalis, Nikolaos, Raitoharju, Jenni, Sankur, Bülent, and Gabbouj, Moncef
    IEEE Transactions on Information Forensics and Security 2020
  14. A Photonic Recurrent Neuron for Time-Series Classification
    Mourgias-Alexandris, George, Passalis, Nikolaos, Dabos, George, Totović, Angelina, Tefas, Anastasios, and Pleros, Nikos
    Journal of Lightwave Technology 2020

2019

  1. Long-term temporal averaging for stochastic optimization of deep neural networks
    Passalis, Nikolaos, and Tefas, Anastasios
    Neural Computing and Applications 2019
  2. Machine learning for forecasting mid-price movements using limit order book data
    Nousi, Paraskevi, Tsantekidis, Avraam, Passalis, Nikolaos, Ntakaris, Adamantios, Kanniainen, Juho, Tefas, Anastasios, Gabbouj, Moncef, and Iosifidis, Alexandros
    IEEE Access 2019
  3. Interactive dimensionality reduction using similarity projections
    Spathis, Dimitris, Passalis, Nikolaos, and Tefas, Anastasios
    Knowledge-Based Systems 2019
  4. Deep reinforcement learning for controlling frontal person close-up shooting
    Passalis, Nikolaos, and Tefas, Anastasios
    Neurocomputing 2019
  5. An all-optical neuron with sigmoid activation function
    Mourgias-Alexandris, George, Tsakyridis, A, Passalis, N, Tefas, Anastasios, Vyrsokinos, K, and Pleros, Nikolaos
    Optics express 2019
  6. Training deep photonic convolutional neural networks with sinusoidal activations
    Passalis, Nikolaos, Mourgias-Alexandris, George, Tsakyridis, Apostolos, Pleros, Nikos, and Tefas, Anastasios
    IEEE Transactions on Emerging Topics in Computational Intelligence 2019
  7. Continuous drone control using deep reinforcement learning for frontal view person shooting
    Passalis, Nikolaos, and Tefas, Anastasios
    Neural Computing and Applications 2019
  8. Discriminative clustering using regularized subspace learning
    Passalis, Nikolaos, and Tefas, Anastasios
    Pattern Recognition 2019
  9. Visual representation decoding from human brain activity using machine learning: A baseline study
    Papadimitriou, Angeliki, Passalis, Nikolaos, and Tefas, Anastasios
    Pattern Recognition Letters 2019
  10. Neuromorphic photonics with coherent linear neurons using dual-IQ modulation cells
    Mourgias-Alexandris, George, Totović, Angelina, Tsakyridis, Apostolos, Passalis, Nikolaos, Vyrsokinos, Konstantinos, Tefas, Anastasios, and Pleros, Nikos
    Journal of Lightwave Technology 2019
  11. Deep adaptive input normalization for time series forecasting
    IEEE Transactions on Neural Networks and Learning Systems 2019

2018

  1. Learning bag-of-embedded-words representations for textual information retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    Pattern Recognition 2018
  2. Explicit ensemble attention learning for improving visual question answering
    Lioutas, Vasileios, Passalis, Nikolaos, and Tefas, Anastasios
    Pattern Recognition Letters 2018
  3. PySEF: A python library for similarity-based dimensionality reduction
    Passalis, Nikolaos, and Tefas, Anastasios
    Knowledge-Based Systems 2018
  4. Unsupervised knowledge transfer using similarity embeddings
    Passalis, Nikolaos, and Tefas, Anastasios
    IEEE Transactions on Neural Networks and Learning Systems 2018
  5. Temporal bag-of-features learning for predicting mid price movements using high frequency limit order book data
    IEEE Transactions on Emerging Topics in Computational Intelligence 2018
  6. Training lightweight deep convolutional neural networks using bag-of-features pooling
    Passalis, Nikolaos, and Tefas, Anastasios
    IEEE Transactions on Neural Networks and Learning Systems 2018

2017

  1. Neural bag-of-features learning
    Passalis, Nikolaos, and Tefas, Anastasios
    Pattern Recognition 2017
  2. Learning neural bag-of-features for large-scale image retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    IEEE Transactions on Systems, Man, and Cybernetics: Systems 2017
  3. Dimensionality reduction using similarity-induced embeddings
    Passalis, Nikolaos, and Tefas, Anastasios
    IEEE Transactions on Neural Networks and Learning Systems 2017

2016

  1. Entropy optimized feature-based bag-of-words representation for information retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    IEEE Transactions on Knowledge and Data Engineering 2016
  2. Information clustering using manifold-based optimization of the bag-of-features representation
    Passalis, Nikolaos, and Tefas, Anastasios
    IEEE Transactions on Cybernetics 2016

Conferences

2021

  1. Robust Hypersphere-based Weight Imprinting for Few-Shot Learning
    In European Signal Processing Conference (EUSIPCO) 2021
  2. Training Noise-Resilient Recurrent Photonic Networks for Financial Time Series Analysis
    Passalis, Nikolaos, Kirtas, M, Mourgias-Alexandris, George, Dabos, George, Pleros, Nikos, and Tefas, Anastasios
    In European Signal Processing Conference (EUSIPCO) 2021
  3. Leveraging Quadratic Spherical Mutual Information Hashing for Fast Image Retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Pattern Recognition (ICPR) 2021
  4. Improving Visual Question Answering using Active Perception on Static Images
    Bozinis, Theodoros, Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Pattern Recognition (ICPR) 2021
  5. End-to-end deep learning with neuromorphic photonics
    Dabos, G, Mourgias-Alexandris, G, Totovic, A, Kirtas, M, Passalis, N, Tefas, A, and Pleros, N
    In Integrated Optics: Devices, Materials, and Technologies XXV 2021
  6. Efficient Online Subclass Knowledge Distillation for Image Classification
    Tzelepi, Maria, Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Pattern Recognition (ICPR) 2021
  7. Human Action Recognition using Recurrent Bag-of-Features Pooling
    Krestenitis, Marios, Passalis, Nikolaos, Iosifidis, Alexandros, Gabbouj, Moncef, and Tefas, Anastasios
    In Workshop Image Mining Theory and Applications (IMTA VII)- 2021
  8. Efficient Realistic Data Generation Framework Leveraging Deep Learning-Based Human Digitization
    Symeonidis, C, Nousi, P, Tosidis, P, Tsampazis, K, Passalis, N, Tefas, A, and Nikolaidis, N
    In International Conference on Engineering Applications of Neural Networks 2021
  9. Learning Sentiment-Aware Trading Strategies for Bitcoin Leveraging Deep Learning-Based Financial News Analysis
    Passalis, N, Seficha, S, Tsantekidis, A, and Tefas, A
    In IFIP International Conference on Artificial Intelligence Applications and Innovations 2021
  10. Temporal Difference Rewards for End-to-end Vision-based Active Robot Tracking using Deep Reinforcement Learning
    Tiritiris, Pavlos, Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Emerging Techniques in Computational Intelligence (ICETCI) 2021

2020

  1. Neuromorphic computing through photonic integrated circuits
    Mourgias-Alexandris, George, Totovic, A, Passalis, N, Dabos, George, Tefas, Anastasios, and Pleros, N
    In Smart Photonic and Optoelectronic Integrated Circuits XXII 2020
  2. Adaptive normalization for forecasting limit order book data using convolutional neural networks
    In IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) 2020
  3. Heterogeneous knowledge distillation using information flow modeling
    Passalis, Nikolaos, Tzelepi, Maria, and Tefas, Anastasios
    In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 2020
  4. Deepbots: A webots-based deep reinforcement learning framework for robotics
    Kirtas, M, Tsampazis, Konstantinos, Passalis, Nikolaos, and Tefas, Anastasios
    In IFIP International Conference on Artificial Intelligence Applications and Innovations 2020
  5. Leveraging deep reinforcement learning for active shooting under open-world setting
    Tzimas, A, Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE International Conference on Multimedia and Expo (ICME) 2020
  6. aColor: Mechatronics, Machine Learning, and Communications in an Unmanned Surface Vehicle
    Villa Escusol, Jose, Taipalmaa, Jussi, Gerasimenko, Mikhail, Pyattaev, Alexander, Ukonaho, Mikko, Zhang, Honglei, Raitoharju, Jenni, Passalis, Nikolaos, Perttula, Antti, Aaltonen, Jussi, and others,
    Proceedings of Transport Research Arena TRA 2020
  7. Photonic Recurrent Neural Networks with Gating Circuit
    Dabos, George, Mourgias-Alexandris, George, Totović, Angelina, Passalis, Nikolaos, Tefas, Anastasios, and Pleros, Nikos
    In Conference on Lasers and Electro-Optics (CLEO) 2020
  8. Improving Universal Style Transfer using Sub-style Decomposition
    Pegios, Paraskevas, Passalis, Nikolaos, and Tefas, Anastasios
    In Hellenic Conference on Artificial Intelligence 2020
  9. Multilayer probabilistic knowledge transfer for learning image representations
    Passalis, Nikolaos, Tzelepi, Maria, and Tefas, Anastasios
    In IEEE International Symposium on Circuits and Systems (ISCAS) 2020
  10. Adaptive Initialization for Recurrent Photonic Networks using Sigmoidal Activations
    Passalis, Nikolaos, Mourgias-Alexandris, George, Pleros, Nikos, and Tefas, Anastasios
    In IEEE International Symposium on Circuits and Systems (ISCAS) 2020
  11. Different color spaces in deep learning-based water segmentation for autonomous marine operations
    Taipalmaa, Jussi, Passalis, Nikolaos, and Raitoharju, Jenni
    In IEEE International Conference on Image Processing (ICIP) 2020
  12. Efficient Adaptive Inference Leveraging Bag-of-Features-based Early Exits
    Passalis, Nikolaos, Raitoharju, Jenni, Gabbouj, Moncef, and Tefas, Anastasios
    In IEEE International Workshop on Multimedia Signal Processing (MMSP) 2020
  13. Leveraging Active Perception for Improving Embedding-based Deep Face Recognition
    Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE International Workshop on Multimedia Signal Processing (MMSP) 2020
  14. Improving Deep Reinforcement Learning for Financial Trading Using Neural Network Distillation
    Tsantekidis, Avraam, Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE International Workshop on Machine Learning for Signal Processing (MLSP) 2020
  15. Global Adaptive Input Normalization for Short-Term Electric Load Forecasting
    Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE Symposium Series on Computational Intelligence (SSCI) 2020
  16. Time-series classification with an all-optical recurrent neuron
    Mourgias-Alexandris, George, Passalis, Nikolaos, Dabos, George, Totović, A, Tefas, Anastasios, and Pleros, Nikos
    In European Conference on Optical Communications (ECOC) 2020

2019

  1. Experimental demonstration of an optical neuron with a logistic Sigmoid activation function
    Mourgias-Alexandris, George, Tsakyridis, Apostolos, Passalis, Nikolaos, Tefas, Anastasios, and Pleros, Nikos
    In Optical Fiber Communication Conference 2019
  2. Deep temporal logistic bag-of-features for forecasting high frequency limit order book time series
    In International Conference on Acoustics, Speech and Signal Processing (ICASSP) 2019
  3. Deep reinforcement learning for financial trading using price trailing
    Zarkias, Konstantinos Saitas, Passalis, Nikolaos, Tsantekidis, Avraam, and Tefas, Anastasios
    In IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) 2019
  4. Variance preserving initialization for training deep neuromorphic photonic networks with sinusoidal activations
    Passalis, Nikolaos, Mourgias-Alexandris, George, Tsakyridis, Apostolos, Pleros, Nikos, and Tefas, Anastasios
    In IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) 2019
  5. Reversible privacy preservation using multi-level encryption and compressive sensing
    Yamaç, Mehmet, Ahishali, Mete, Passalis, Nikolaos, Raitoharju, Jenni, Sankur, Bulent, and Gabbouj, Moncef
    In European Signal Processing Conference (EUSIPCO) 2019
  6. Face verification and recognition for digital forensics and information security
    Amato, Giuseppe, Falchi, Fabrizio, Gennaro, Claudio, Massoli, Fabio Valerio, Passalis, Nikolaos, Tefas, Anastasios, Trivilini, Alessandro, and Vairo, Claudio
    In International Symposium on Digital Forensics and Security (ISDFS) 2019
  7. Adaptive inference using hierarchical convolutional bag-of-features for low-power embedded platforms
    Passalis, Nikolaos, Raitoharju, Jenni, Tefas, Anastasios, and Gabbouj, Moncef
    In IEEE International Conference on Image Processing (ICIP) 2019
  8. Class-based variational representation learning for robust image retrieval
    In IEEE International Conference on Image Processing (ICIP) 2019
  9. High-resolution water segmentation for autonomous unmanned surface vehicles: a novel dataset and evaluation
    Taipalmaa, Jussi, Passalis, Nikolaos, Zhang, Honglei, Gabbouj, Moncef, and Raitoharju, Jenni
    In IEEE International Workshop on Machine Learning for Signal Processing (MLSP) 2019
  10. Curriculum-based teacher ensemble for robust neural network distillation
    Panagiotatos, Georgios, Passalis, Nikolaos, Iosifidis, Alexandros, Gabbouj, Moncef, and Tefas, Anastasios
    In European Signal Processing Conference (EUSIPCO) 2019
  11. Less Is More: Deep Learning Using Subjective Annotations For Sentiment Analysis From Social Media
    Tzogka, Christina, Passalis, Nikolaos, Iosifidis, Alexandros, Gabbouj, Moncef, and Tefas, Anastasios
    In IEEE International Workshop on Machine Learning for Signal Processing (MLSP) 2019
  12. A linear photonic neuron using an extended iq modulator cell for enabling all-optical coherent sigmoid neurons
    Mourgias-Alexandris, George, Totovic, Angelina, Tsakyridis, Apostolos, Passalis, Nikolaos, Tefas, Anastasios, Vyrsokinos, Konstantinos, and Pleros, Nikos
    In European Conference on Optical Communication (ECOC) 2019

2018

  1. Visual question answering using explicit visual attention
    Lioutas, Vasileios, Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE International Symposium on Circuits and Systems (ISCAS) 2018
  2. Efficient camera control using 2D visual information for unmanned aerial vehicle-based cinematography
    Passalis, Nikolaos, Tefas, Anastasios, and Pitas, Ioannis
    In IEEE International Symposium on Circuits and Systems (ISCAS) 2018
  3. Deep reinforcement learning for frontal view person shooting using drones
    Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE Conference on Evolving and Adaptive Intelligent Systems (EAIS) 2018
  4. Learning deep representations with probabilistic knowledge transfer
    Passalis, Nikolaos, and Tefas, Anastasios
    In European Conference on Computer Vision (ECCV) 2018
  5. Learning Discriminative Representations for Big Data Clustering Using Similarity-Based Dimensionality Reduction
    Passalis, Nikolaos, and Tefas, Anastasios
    In IEEE Image, Video, and Multidimensional Signal Processing Workshop (IVMSP) 2018
  6. Decoding Generic Visual Representations from Human Brain Activity Using Machine Learning
    Papadimitriou, Angeliki, Passalis, Nikolaos, and Tefas, Anastasios
    In European Conference on Computer Vision (ECCV) Workshops 2018
  7. Neural Network Knowledge Transfer using Unsupervised Similarity Matching
    Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Pattern Recognition (ICPR) 2018
  8. Fast, visual and interactive semi-supervised dimensionality reduction
    Spathis, Dimitris, Passalis, Nikolaos, and Tefas, Anastasios
    In European Conference on Computer Vision (ECCV) Workshops 2018
  9. Accelerating Similarity-Based Discriminant Analysis Using Class-Specific Prototypes
    Passalis, Nikolas, and Tefas, Anastasios
    In IEEE International Conference on Image Processing (ICIP) 2018

2017

  1. Learning Bag-of-Features Pooling for Deep Convolutional Neural Networks
    Passalis, Nikolaos, and Tefas, Anastasios
    In The IEEE International Conference on Computer Vision (ICCV) 2017
  2. Improving Face Pose Estimation Using Long-Term Temporal Averaging for Stochastic Optimization
    Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Engineering Applications of Neural Networks (EANN) 2017
  3. Forecasting stock prices from the limit order book using convolutional neural networks
    Tsantekidis, Avraam, Passalis, Nikolaos, Tefas, Anastasios, Kanniainen, Juho, Gabbouj, Moncef, and Iosifidis, Alexandros
    In IEEE Conference on Business Informatics (CBI) 2017
  4. Using deep learning to detect price change indications in financial markets
    Tsantekidis, Avraam, Passalis, Nikolaos, Tefas, Anastasios, Kanniainen, Juho, Gabbouj, Moncef, and Iosifidis, Alexandros
    In European Signal Processing Conference (EUSIPCO) 2017
  5. Concept detection and face pose estimation using lightweight convolutional neural networks for steering drone video shooting
    Passalis, Nikolaos, and Tefas, Anastasios
    In European Signal Processing Conference (EUSIPCO) 2017
  6. Time-series classification using neural bag-of-features
    Passalis, Nikolaos, Tsantekidis, Avraam, Tefas, Anastasios, Kanniainen, Juho, Gabbouj, Moncef, and Iosifidis, Alexandros
    In European Signal Processing Conference (EUSIPCO) 2017

2016

  1. Spectral clustering using optimized bag-of-features
    Passalis, Nikolaos, and Tefas, Anastasios
    In Hellenic Conference on Artificial Intelligence 2016
  2. Spatial bag of features learning for large scale face image retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    In INNS Conference on Big Data 2016
  3. Bag of Embedded Words learning for text retrieval
    Passalis, Nikolaos, and Tefas, Anastasios
    In International Conference on Pattern Recognition (ICPR) 2016

2015

  1. Multispot: Spotting sentiments with semantic aware multilevel cascaded analysis
    Chatzakou, Despoina, Passalis, Nikolaos, and Vakali, Athena
    In International Conference on Big Data Analytics and Knowledge Discovery 2015