George Fragiadakis

Dr. George Fragiadakis

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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23 March 2023 in Computing
Verified
Journal Article
Open access
PDF file
GFGeorge Fragiadakis
George Fragiadakis
VLVasiliki Liagkou
Vasiliki Liagkou
Evangelia FiliopoulouEvangelia Filiopoulou
Evangelia Filiopoulou
DFDimitris Fragkakis
Dimitris Fragkakis
Christos MichalakelisChristos Michalakelis
Christos Michalakelis
Mara NikolaidouMara Nikolaidou
Mara Nikolaidou
As cloud computing has grown in popularity, several different models and deployment strategies have emerged, fulfilling specific needs of different users. Thus cloud service selection is a major task that combines business and technical aspects. Several cloud providers categorize their bundles to help users find the best fit. However, the policy behind this categorization is unclear, making it difficult to be consistent among providers. Therefore, this work explores the complication of selecting the optimal cloud service among numerous and comparable solutions and introduces a selection framework for cloud services based on clustering analysis, providing an overall size categorization of cloud services derived from the cloud market and making the categorization policy explicit and homogeneous across all providers. Finally, a real-word case study is presented, highlighting the application of the proposed framework.

1 February 2022 in Simulation Modelling Practice and Theory
Verified
Journal Article
Closed access
VLVasiliki Liagkou
Vasiliki Liagkou
GFGeorge Fragiadakis
George Fragiadakis
Evangelia FiliopoulouEvangelia Filiopoulou
Evangelia Filiopoulou
CMChristos Michalakelis
Christos Michalakelis
KTKamalakis Thomas
Kamalakis Thomas
Mara NikolaidouMara Nikolaidou
Mara Nikolaidou

19 August 2023 in Future Internet
Verified
Journal Article
Open access
PDF file
GFGeorge Fragiadakis
George Fragiadakis
Evangelia FiliopoulouEvangelia Filiopoulou
Evangelia Filiopoulou
Christos MichalakelisChristos Michalakelis
Christos Michalakelis
KTKamalakis Thomas
Kamalakis Thomas
Mara NikolaidouMara Nikolaidou
Mara Nikolaidou
When exploring alternative cloud solution designs, it is important to also consider cost. Thus, having a comprehensive view of the cloud market and future price evolution allows well-informed decisions to choose between alternatives. Cloud providers offer various service types with different pricing policies. Currently, infrastructure-as-a-Service (IaaS) is considered the most mature cloud service, while reserved instances, where virtual machines are reserved for a fixed period of time, have the largest market share. In this work, we employ a machine-learning approach based on the CatBoost algorithm to explore a price-prediction model for the reserve instance market. The analysis is based on historical data provided by Amazon Web Services from 2016 to 2022. Early results demonstrate the machine-learning model’s ability to capture the underlying evolution patterns and predict future trends. Findings suggest that prediction accuracy is not improved by integrating data from older time periods.

20 December 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
GFGeorge Fragiadakis
George Fragiadakis
Anargyros TsadimasAnargyros Tsadimas
Anargyros Tsadimas
Evangelia FiliopoulouEvangelia Filiopoulou
Evangelia Filiopoulou
GKGeorge Kousiouris
George Kousiouris
Christos MichalakelisChristos Michalakelis
Christos Michalakelis
Mara NikolaidouMara Nikolaidou
Mara Nikolaidou
To maximize the business value of the cloud, the cost of cloud solutions is explored alongside technical quality and performance. To enable this form of exploration engineering, finance and business teams collaborate in the context of FinOps, the operational framework that provides the required decision-making. Prominent providers, such as Google and Microsoft, provide FinOps to their customers, integrating cost factors when designing a cloud solution. However, different providers apply different pricing policies for their products, and these policies also change through time. Therefore, there are numerous efforts to explore price evolution through time for different cloud products applying different decision-making methods using different datasets. In an effort to establish a systematic approach to support decision-making on alternative pricing policies for cloud services and compare them across services and providers, the CloudPricingOps framework is proposed in this paper. It constitutes a decision support system that provides alternative decision-making methods, such as hedonic models, time series, and clustering and machine learning techniques, to deal with problems related to cloud product pricing policy analysis, comparison and prediction. It also constitutes a systematic method of discrete steps to integrate additional decision-making methods to deal with these problems and input datasets to be used regardless of the method or the cloud pricing problem that needs to be solved. Two discrete examples based on real data are also presented in this paper to demonstrate the usefulness of the CloudPricingOps framework for cloud engineering and business teams.

2 October 2025 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Evangelia FiliopoulouEvangelia Filiopoulou
Evangelia Filiopoulou
GDGeorgia Dede
Georgia Dede
GFGeorge Fragiadakis
George Fragiadakis
SESpyridon Evangelatos
Spyridon Evangelatos
TSTeta Stamati
Teta Stamati
KTKamalakis Thomas
Kamalakis Thomas
Cybersecurity is increasingly recognized as a key enabler of Sustainable Development Goals (SDGs) and especially SDG 3 (Good Health and Well-being) as healthcare systems become more digitized. This study prioritizes cybersecurity control families from the NIST 800-53r5 framework using a structured framework combining the Analytic Hierarchy Process (AHP) and the Impact–Feasibility Matrix. From the impact–feasibility perspective, expert judgment reveals that while impact is the primary driver in selecting controls, feasibility—particularly budget and cost constraints—plays a decisive role in real-world implementation. A group of fifteen experts, including cybersecurity officers, health IT professionals, and public health advisors, has participated in structured surveys as per the methodological framework of this paper. Financial and budgetary limitations emerged as the top feasibility barrier, often determining whether high-impact controls are deployed or delayed. This underscores the need for strategic investments and phased implementation approaches, particularly in resource-constrained health systems. The results provide a practical roadmap for policymakers and healthcare administrators to allocate cybersecurity resources effectively, balancing technical necessity with economic feasibility to support resilient digital health infrastructures.

12 September 2024 in Journal of Grid Computing
Verified
Journal Article
Closed access
PDF file
VLVasiliki Liagkou
Vasiliki Liagkou
GFGeorge Fragiadakis
George Fragiadakis
EFEvangelia Filiopoulou
Evangelia Filiopoulou
Christos MichalakelisChristos Michalakelis
Christos Michalakelis
Anargyros TsadimasAnargyros Tsadimas
Anargyros Tsadimas
Mara NikolaidouMara Nikolaidou
Mara Nikolaidou