Lia-Anca Hangan

Dr. Lia-Anca Hangan

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

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

Representative Publications

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19 February 2024 in Smart Cities
Verified
Journal Article
Open access
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Gabriel Ioan ArcasGabriel Ioan Arcas
Gabriel Ioan Arcas
Tudor CioaraTudor Cioara
Tudor Cioara
Ionut AnghelIonut Anghel
Ionut Anghel
DLDragos Bogdan Lazea
Dragos Bogdan Lazea
LHLia-Anca Hangan
Lia-Anca Hangan
The management of decentralized energy resources and smart grids needs novel data-driven low-latency applications and services to improve resilience and responsiveness and ensure closer to real-time control. However, the large-scale integration of Internet of Things (IoT) devices has led to the generation of significant amounts of data at the edge of the grid, posing challenges for the traditional cloud-based smart-grid architectures to meet the stringent latency and response time requirements of emerging applications. In this paper, we delve into the energy grid and computational distribution architectures, including edge–fog–cloud models, computational orchestration, and smart-grid frameworks to support the design and offloading of grid applications across the computational continuum. Key factors influencing the offloading process, such as network performance, data and Artificial Intelligence (AI) processes, computational requirements, application-specific factors, and energy efficiency, are analyzed considering the smart-grid operational requirements. We conduct a comprehensive overview of the current research landscape to support decision-making regarding offloading strategies from cloud to fog or edge. The focus is on metaheuristics for identifying near-optimal solutions and reinforcement learning for adaptively optimizing the process. A macro perspective on determining when and what to offload in the smart grid is provided for the next-generation AI applications, offering an overview of the features and trade-offs for selecting between federated learning and edge AI solutions. Finally, the work contributes to a comprehensive understanding of edge offloading in smart grids, providing a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis to support cost–benefit analysis in decision-making regarding offloading strategies.

9 July 2022 in Water
Verified
Journal Article
Open access
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LHLia-Anca Hangan
Lia-Anca Hangan
CCCostin Gabriel Chiru
Costin Gabriel Chiru
DADiana Arsene
Diana Arsene
ZCZoltan Czako
Zoltan Czako
DLDragos Florin Lisman
Dragos Florin Lisman
GSGheorghe Sebestyen
Gheorghe Sebestyen
Water supply systems are essential for a modern society. This article presents an overview of the latest research related to information and communication technology systems for water resource monitoring, control and management. The main objective of our review is to show how emerging technologies offer support for smart administration of water infrastructures. The paper covers research results related to smart cities, smart water monitoring, big data, data analysis and decision support. Our evaluation reveals that there are many possible solutions generated through combinations of advanced methods. Emerging technologies open new possibilities for including new functionalities such as social involvement in water resource management. This review offers support for researchers in the area of water monitoring and management to identify useful models and technologies for designing better solutions.

1 December 2019 in Acta Universitatis Sapientiae, Informatica
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Journal Article
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GKGyörgy Kovács
György Kovács
GSGheorghe Sebestyen
Gheorghe Sebestyen
LHLia-Anca Hangan
Lia-Anca Hangan
Time-series are ordered sequences of discrete-time data. Due to their temporal dimension, anomaly detection techniques used in time-series have to take into consideration time correlations and other time-related particularities. Generally, in order to evaluate the quality of an anomaly detection technique, the confusion matrix and its derived metrics such as precision and recall are used. These metrics, however, do not take this temporal dimension into consideration. In this paper, we propose three metrics that can be used to evaluate the quality of a classification, while accounting for the temporal dimension found in time-series data.

16 December 2022 in Journal of Gastrointestinal and Liver Diseases
Verified
Journal Article
Open access
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PSPopa Stefan-Lucian
Popa Stefan-Lucian
TBTeodora Surdea Blaga
Teodora Surdea Blaga
Dan L DumitrascuDan L Dumitrascu
Dan L Dumitrascu
GCGiuseppe Chiarioni
Giuseppe Chiarioni
ESEdoardo Vincenzo Savarino
Edoardo Vincenzo Savarino
ZCZoltan Czako
Zoltan Czako
Background and Aims: High-resolution esophageal manometry (HREM) is the gold standard procedure used for the diagnosis of esophageal motility disorders (EMD). Artificial intelligence (AI) might provide an efficient solution for the automatic diagnosis of EMD by improving the subjective interpretation of HREM images. The aim of our study was to develop an AI-based system, using neural networks, for the automatic diagnosis of HREM images, based on one wet swallow raw image. Methods: In the first phase of the study, the manometry recordings of our patients were retrospectively analyzed by three experienced gastroenterologists, to verify and confirm the correct diagnosis. In the second phase of the study raw images were used to train an artificial neural network. We selected only those tracings with ten test swallows that were available for analysis, including a total of 1570 images. We had 10 diagnosis categories, as follows: normal, type I achalasia, type II achalasia, type III achalasia, esophago-gastric junction outflow obstruction, jackhammer oesophagus, absent contractility, distal esophageal spasm, ineffective esophageal motility, and fragmented peristalsis, based on Chicago classification v3.0 for EMDs. Results: The raw images were cropped, binarized, and automatically divided in 3 parts: training, testing, validation. We used Inception V3 CNN model, pre-trained on ImageNet. We developed a custom classification layer, that allowed the CNN to classify each wet swallow image from the HREM system into one of the diagnosis categories mentioned above. Our algorithm was highly accurate, with an overall precision of more than 93%. Conclusion: Our neural network approach using HREM images resulted in a high accuracy automatic diagnosis of EMDs.

13 July 2022 in Sensors
Verified
Journal Article
Open access
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TBTeodora Surdea Blaga
Teodora Surdea Blaga
GSGheorghe Sebestyen
Gheorghe Sebestyen
ZCZoltan Czako
Zoltan Czako
LHLia-Anca Hangan
Lia-Anca Hangan
Dan L DumitrascuDan L Dumitrascu
Dan L Dumitrascu
PSPopa Stefan-Lucian
Popa Stefan-Lucian
The goal of this paper is to provide a Machine Learning-based solution that can be utilized to automate the Chicago Classification algorithm, the state-of-the-art scheme for esophageal motility disease identification. First, the photos were preprocessed by locating the area of interest—the precise instant of swallowing. After resizing and rescaling the photos, they were utilized as input for the Deep Learning models. The InceptionV3 Deep Learning model was used to identify the precise class of the IRP. We used the DenseNet201 CNN architecture to classify the images into 5 different classes of swallowing disorders. Finally, we combined the results of the two trained ML models to automate the Chicago Classification algorithm. With this solution we obtained a top-1 accuracy and f1-score of 86% with no human intervention, automating the whole flow, from image preprocessing until Chicago classification and diagnosis.

30 December 2021 in Sensors
Verified
Journal Article
Open access
PDF file
ZCZoltan Czako
Zoltan Czako
TBTeodora Surdea Blaga
Teodora Surdea Blaga
GSGheorghe Sebestyen
Gheorghe Sebestyen
LHLia-Anca Hangan
Lia-Anca Hangan
Dan L DumitrascuDan L Dumitrascu
Dan L Dumitrascu
PSPopa Stefan-Lucian
Popa Stefan-Lucian
High-resolution esophageal manometry is used for the study of esophageal motility disorders, with the help of catheters with up to 36 sensors. Color pressure topography plots are generated and analyzed and using the Chicago algorithm a final diagnosis is established. One of the main parameters in this algorithm is integrated relaxation pressure (IRP). The procedure is time consuming. Our aim was to firstly develop a machine learning based solution to detect probe positioning failure and to create a classifier to automatically determine whether the IRP is in the normal range or higher than the cut-off, based solely on the raw images. The first step was the preprocessing of the images, by finding the region of interest—the exact moment of swallowing. Afterwards, the images were resized and rescaled, so they could be used as input for deep learning models. We used the InceptionV3 deep learning model to classify the images as correct or failure in catheter positioning and to determine the exact class of the IRP. The accuracy of the trained convolutional neural networks was above 90% for both problems. This work is just the first step in fully automating the Chicago Classification, reducing human intervention.