Nikolaos Doulamis

Prof. Nikolaos Doulamis

Department of Rural Surveying Engineering and Geoinformatics Engineering, National Technical University of Athens, 157 80 Athens, Greece
orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 March 2023 in IEEE Geoscience and Remote Sensing Letters
Verified
Journal Article
Open access
ATAnastasios Temenos
Anastasios Temenos
NTNikos Temenos
Nikos Temenos
Maria KaselimiMaria Kaselimi
Maria Kaselimi
Anastasios DoulamisAnastasios Doulamis
Anastasios Doulamis
NDNikolaos Doulamis
Nikolaos Doulamis
An interpretable deep learning framework for land use and land cover (LULC) classification in remote sensing using Shapley additive explanations (SHAPs) is introduced. It utilizes a compact convolutional neural network (CNN) model for the classification of satellite images and then feeds the results to a SHAP deep explainer so as to strengthen the classification results. The proposed framework is applied to Sentinel-2 satellite images containing 27000 images of pixel size $64 \times 64$ and operates on three-band combinations, reducing the model’s input data by 77% considering that 13 channels are available, while at the same time investigating on how different spectrum bands affect predictions on the dataset’s classes. Experimental results on the EuroSAT dataset demonstrate the CNN’s accurate classification with an overall accuracy of 94.72 %, whereas the classification accuracy on three-band combinations on each of the dataset’s classes highlights its improvement when compared to standard approaches with larger number of trainable parameters. The SHAP explainable results of the proposed framework shield the network’s predictions by showing correlation values that are relevant to the predicted class, thereby improving the classifications occurring in urban and rural areas with different land uses in the same scene.

2 November 2021 in Technologies
Verified
Journal Article
Open access
PDF file
Ioannis MarkoulidakisIoannis Markoulidakis
Ioannis Markoulidakis
IRIoannis Rallis
Ioannis Rallis
IGIoannis Georgoulas
Ioannis Georgoulas
GKGeorge Kopsiaftis
George Kopsiaftis
NDNikolaos Doulamis
Nikolaos Doulamis
NDNikolaos Doulamis
Nikolaos Doulamis
The current paper presents a novel method for reducing a multiclass confusion matrix into a 2×2 version enabling the exploitation of the relevant performance metrics and methods such as the receiver operating characteristic and area under the curve for the assessment of different classification algorithms. The reduction method is based on class grouping and leads to a special type of matrix called the reduced confusion matrix. The developed method is then exploited for the assessment of state of the art machine learning algorithms applied on the net promoter score classification problem in the field of customer experience analytics indicating the value of the proposed method in real world classification problems.

17 February 2020 in IEEE Transactions on Smart Grid
Verified
Journal Article
Closed access
Maria KaselimiMaria Kaselimi
Maria Kaselimi
NDNikolaos Doulamis
Nikolaos Doulamis
AVAthanasios Voulodimos
Athanasios Voulodimos
Eftychios ProtopapadakisEftychios Protopapadakis
Eftychios Protopapadakis
ADAnastasios Doulamis
Anastasios Doulamis
Energy disaggregation, or Non-Intrusive Load Mon-itoring (NILM), describes various processes aiming to identify the individual contribution of appliances, given the aggregate power signal. In this paper, a non-causal adaptive context-aware bidirec-tional deep learning model for energy disaggregation is intro-duced. The proposed model, CoBiLSTM, harnesses the represen-tational power of deep recurrent Long Short-Term Memory (LSTM) neural networks, while fitting two basic properties of NILM problem which state of the art methods do not appropri-ately account for: non-causality and adaptivity to contextual fac-tors (e.g. seasonality). A Bayesian-optimized framework is intro-duced to select the best configuration of the proposed regression model, driven by a self-training adaptive mechanism. Further-more, the proposed model is structured in a modular way to ad-dress multi-dimensionality issues that arise when the number of appliances increases. Experimental results indicate the proposed method’s superiority compared to the current state of the art.

28 January 2024 in Computers in Biology and Medicine
Verified
Journal Article
Open access
SMSotirios Messinis
Sotirios Messinis
NTNikos Temenos
Nikos Temenos
Nicholas E ProtonotariosNicholas E Protonotarios
Nicholas E Protonotarios
IRIoannis Rallis
Ioannis Rallis
Dimitris K KalogerasDimitris K Kalogeras
Dimitris K Kalogeras
NDNikolaos Doulamis
Nikolaos Doulamis
Over the past five years, interest in the literature regarding the security of the Internet of Medical Things (IoMT) has increased. Due to the enhanced interconnectedness of IoMT devices, their susceptibility to cyber-attacks has proportionally escalated. Motivated by the promising potential of AI-related technologies to improve certain cybersecurity measures, we present a comprehensive review of this emerging field. In this review, we attempt to bridge the corresponding literature gap regarding modern cybersecurity technologies that deploy AI techniques to improve their performance and compensate for security and privacy vulnerabilities. In this direction, we have systematically gathered and classified the extensive research on this topic. Our findings highlight the fact that the integration of machine learning (ML) and deep learning (DL) techniques improves both the performance of cybersecurity measures and their speed, reliability, and effectiveness. This may be proven to be useful for improving the security and privacy of IoMT devices. Furthermore, by considering the numerous advantages of AI technologies as opposed to their core cybersecurity counterparts, including blockchain, anomaly detection, homomorphic encryption, differential privacy, federated learning, and so on, we provide a structured overview of the current scientific trends. We conclude with considerations for future research, emphasizing the promising potential of AI-driven cybersecurity in the IoMT landscape, especially in patient data protection and in data-driven healthcare.

5 August 2022 in Sensors
Verified
Journal Article
Open access
PDF file
Maria KaselimiMaria Kaselimi
Maria Kaselimi
Eftychios ProtopapadakisEftychios Protopapadakis
Eftychios Protopapadakis
AVAthanasios Voulodimos
Athanasios Voulodimos
NDNikolaos Doulamis
Nikolaos Doulamis
Anastasios DoulamisAnastasios Doulamis
Anastasios Doulamis
Non-intrusive load monitoring (NILM) is the task of disaggregating the total power consumption into its individual sub-components. Over the years, signal processing and machine learning algorithms have been combined to achieve this. Many publications and extensive research works are performed on energy disaggregation or NILM for the state-of-the-art methods to reach the desired performance. The initial interest of the scientific community to formulate and describe mathematically the NILM problem using machine learning tools has now shifted into a more practical NILM. Currently, we are in the mature NILM period where there is an attempt for NILM to be applied in real-life application scenarios. Thus, the complexity of the algorithms, transferability, reliability, practicality, and, in general, trustworthiness are the main issues of interest. This review narrows the gap between the early immature NILM era and the mature one. In particular, the paper provides a comprehensive literature review of the NILM methods for residential appliances only. The paper analyzes, summarizes, and presents the outcomes of a large number of recently published scholarly articles. Furthermore, the paper discusses the highlights of these methods and introduces the research dilemmas that should be taken into consideration by researchers to apply NILM methods. Finally, we show the need for transferring the traditional disaggregation models into a practical and trustworthy framework.

2 February 2022 in IEEE Transactions on Neural Networks and Learning Systems
Verified
Journal Article
Open access
Maria KaselimiMaria Kaselimi
Maria Kaselimi
AVAthanasios Voulodimos
Athanasios Voulodimos
IDIoannis Daskalopoulos
Ioannis Daskalopoulos
NDNikolaos Doulamis
Nikolaos Doulamis
Anastasios DoulamisAnastasios Doulamis
Anastasios Doulamis
Understanding the dynamics of deforestation and land uses of neighboring areas is of vital importance for the design and development of appropriate forest conservation and management policies. In this article, we approach deforestation as a multilabel classification (MLC) problem in an endeavor to capture the various relevant land uses from satellite images. To this end, we propose a multilabel vision transformer model, ForestViT, which leverages the benefits of the self-attention mechanism, obviating any convolution operations involved in commonly used deep learning models utilized for deforestation detection. Experimental evaluation in open satellite imagery datasets yields promising results in the case of MLC, particularly for imbalanced classes, and indicates ForestViT's superiority compared with well-established convolutional structures (ResNET, VGG, DenseNet, and ModileNet neural networks). This superiority is more evident for minority classes.