EDBT 2026 Demo / reviewers in the wild / expert
Christos Michalakelis
dblp:24/751
· DBLP profile ↗
9ranked-venue papers
2as first author
6since 2021 · last 2025
0000-0002-4401-5058ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Systems, architecture and hardware · 3 · 3 since 2021Human-computer interaction and ubiquitous computing · 2 · 1 first-author · 1 since 2021Artificial intelligence and machine learning · 1 · 1 first-authorSoftware engineering, systems software and programming languages · 1 · 1 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2025 | Are Public Cloud Solutions Really Cheaper? Cost Analysis Findings from the Migration Project of a Large-Scale Governmental OrganizationabstractThis study investigates whether cloud provider solutions offer cost advantages over private cloud infrastructures in large-scale government settings. Focusing on the case of Greek Governmental Cloud (GCloud), we conduct a comprehensive cost comparison across three deployment models: the existing on-premise infrastructure, an IaaS cloud provider solution and a PaaS cloud provider solution. The cost analysis considers a five-year operational time window and uses real procurement data and updated discount policies. We take into consideration that the organization already has data center infrastructure and explores the migration options to cloud provider solutions. The cost analysis findings show that although provider solution can match or slightly undercut on-premise costs under specific conditions where agility is important, there is no financial advantage regarding standard operation needs. This real-world case study of the Greek Government Cloud highlights that cloud migration decisions for large organizations, with existing IT infrastructures, should be taken after thorough cost evaluation, accurate workload analysis, and a deep understanding of dynamic pricing models. Moreover, this study offers practical recommendations to decision-makers that navigate complex infrastructure choices. While infrastructure choices involve factors such as performance, security, and operational flexibility, this study intentionally focuses solely on the cost, aiming to provide a clear and quantifiable economic comparison. In general, this study aims to open a discussion about whether Cloud solutions are a panacea, especially in government settings. Vassilis Dalakas, Evangelia Filiopoulou, Cleopatra Bardaki, George Fragiadakis, Anargyros Tsadimas, Christos Michalakelis, Mara Nikolaidou, Dimosthenis Anagnostopoulos |
IC2E | 6 |
| 2024 | The cost perspective of adopting Large Language Model-as-a-ServiceabstractLarge Language Models (LLMs) are pivotal in generative AI applications. Consequently, major cloud providers, such as Amazon, Azure, and Google, introduce the offering of LLM-as-a-Service (LLMaaS) products to enable businesses to leverage NLP, data analysis, and predictive modeling in their cloud solutions. This paper explores the incorporation of LLM-as-a-Service solutions into business workflows with a focus on inference costs. We review various LLMaaS offerings and conduct a comparative analysis based on a real-world case study of an AI chatbot. Vasiliki Liagkou, Evangelia Filiopoulou, George Fragiadakis, Mara Nikolaidou, Christos Michalakelis |
JCC | 5 |
| 2024 | Assessing the Complexity of Cloud Pricing Policies: A Comparative Market Analysis
Vasiliki Liagkou, George Fragiadakis, Evangelia Filiopoulou, Christos Michalakelis, Anargyros Tsadimas, Mara Nikolaidou |
J. Grid Comput. | 4 |
| 2021 | Exploring the Barriers of Educational Innovation
Marina Aivazidi, Christos Michalakelis |
ITS | 2 |
| 2021 | Safety requirements for symbiotic human-robot collaboration systems in smart factories: a pairwise comparison approach to explore requirements dependencies
Georgia Dede, Persefoni Mitropoulou, Mara Nikolaidou, Thomas Kamalakis, Christos Michalakelis |
Requir. Eng. | 5 |
| 2021 | On the Efficiency of Cloud Providers: A DEA Approach Incorporating Categorical VariablesabstractCloud computing is a growing industry and it has already dominated many IT markets segments. Cloud providers offer numerous equivalent IaaS services aiming to fulfill clients' requirements. In addition, cloud clients need to choose solutions that minimize costs without compromising efficiency though. However, not only the confusion due to the large variety of cloud services but also the uncertainty about the efficiency specifications that their cloud services should have, can make cloud computing services selection a difficult task for the users. Into this context, this paper presents an approach to a multi-attribute decision-making problem that focuses on the calculation of efficiency of IaaS cloud services as a measurable driver for both clients and providers. A DEA input-oriented model is described, which estimates efficiency of cloud services based on functional and non-functional parameters. Furthermore, the contribution of functional and non-functional features to the overall performance is examined. This innovative model urges providers to optimize the efficiency of their services aiming to increase their market share and, at the same time, assists clients in choosing a cost-effective cloud solution. Evangelia Filiopoulou, Persefoni Mitropoulou, Nikolas Lionis, Christos Michalakelis |
IEEE Trans. Cloud Comput. | 4 |
| 2015 | A Hedonic Price Index for Cloud Computing Services
Persefoni Mitropoulou, Evangelia Filiopoulou, Stavroula Tsaroucha, Christos Michalakelis, Mara Nikolaidou |
CLOSER | 4 |
| 2012 | Dynamic estimation of markets exhibiting a prey-predator behavior
Christos Michalakelis, Charisios Christodoulos, Dimitris Varoutas, Thomas Sphicopoulos |
Expert Syst. Appl. | 1 |
| 2011 | Modeling Competition in the Telecommunications Market Based on Concepts of Population BiologyabstractBased on concepts of ecology modeling and specifically on population biology, a methodology for describing a high-technology market's dynamics is developed and presented. The importance of the aforementioned methodology is its capability to estimate and forecast the degree of competition, market equilibrium, and market concentration, the latter expressed by corresponding market shares, in the high-technology environment. Evaluation of the presented methodology in the area of telecommunications led to accurate results, as compared to historical data, in a specific case study. Apart from a very good estimation of the market's behavior, this methodology presents a very good forecasting ability, which can provide valuable inputs for managerial and regulatory decisions and strategic planning, to the players of a high-technology market, described by high entry barriers. Christos Michalakelis, Thomas Sphicopoulos, Dimitris Varoutas |
IEEE Trans. Syst. Man Cybern. Part C | 1 |