Georgios Papayiannis

Dr. Georgios Papayiannis


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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4 March 2020 in Energies
Verified
Journal Article
Open access
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Nikolaos KampelisNikolaos Kampelis
Nikolaos Kampelis
GPGeorgios Papayiannis
Georgios Papayiannis
DKDionysia Kolokotsa
Dionysia Kolokotsa
GGGeorge Galanis
George Galanis
DIDaniela Isidori
Daniela Isidori
AYAthanasios N. Yannacopoulos
Athanasios N. Yannacopoulos
The operation of buildings is linked to approximately 36% of the global energy consumption, 40% of greenhouse gas emissions, and climate change. Assessing the energy consumption and efficiency of buildings is a complex task addressed by a variety of methods. Building energy modeling is among the dominant methodologies in evaluating the energy efficiency of buildings commonly applied for evaluating design and renovation energy efficiency measures. Although building energy modeling is a valuable tool, it is rarely the case that simulation results are assessed against the building’s actual energy performance. In this context, the simulation results of the HVAC energy consumption in the case of a smart industrial near-zero energy building are used to explore areas of uncertainty and deviation of the building energy model against measured data. Initial model results are improved based on a trial and error approach to minimize deviation based on key identified parameters. In addition, a novel approach based on functional shape modeling and Kalman filtering is developed and applied to further minimize systematic discrepancies. Results indicate a significant initial performance gap between the initial model and the actual energy consumption. The efficiency and the effectiveness of the developed integrated model is highlighted.

1 April 2022 in Journal of Dynamics and Games
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Journal Article
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GPGeorgios Papayiannis
Georgios Papayiannis
In this work the problem of optimal harvesting policy selection for natural resources management under model uncertainty is investigated. Under the framework of the neoclassical growth model dynamics, the associated optimal control problem is investigated by introducing the concept of model uncertainty on the initial conditions of the operational procedure. At this stage, the notion of convex risk measures, and in particular the class of Frechet risk measures, is employed in order to quantify the total operational and marginal risk, whereas simultaneously obtaining robust to model uncertainty harvesting strategies.

1 January 2023 in Journal of Industrial and Management Optimization
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Journal Article
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GPGeorgios Papayiannis
Georgios Papayiannis
HLHellenic Naval Academy Mathematical Modelling And Applications Laboratory
Hellenic Naval Academy Mathematical Modelling And Applications Laboratory
The problem of asset liability management (ALM) is a classic problem of the financial mathematics and of great interest for the banking institutions and insurance companies. Several formulations of this problem under various model settings have been studied under the Mean-Variance (MV) principle perspective. In this paper, the ALM problem is revisited under the context of model uncertainty in the one-stage framework. In practice, uncertainty issues appear to several aspects of the problem, e.g. liability process characteristics, market conditions, inflation rates, inside information effects, etc. A framework relying on the notion of the Wasserstein barycenter is presented which is able to treat robustly this type of ambiguities by appropriate handling the various information sources (models) and appropriately reformulating the relevant decision making problem. The proposed framework can be applied to a number of different model settings leading to the selection of investment portfolios that remain robust to the various uncertainties appearing in the market. The paper is concluded with a numerical experiment for a static version of the ALM problem, employing standard modelling approaches, illustrating the capabilities of the proposed method with very satisfactory results in retrieving the true optimal strategy even in high noise cases.

27 December 2022
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Book Chapter
Closed access
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Phoebe KoundouriPhoebe Koundouri
Phoebe Koundouri
GPGeorgios Papayiannis
Georgios Papayiannis
AYA. N. Yannacopoulos
A. N. Yannacopoulos

15 May 2023
Verified
Conference Paper
Open access
GPGeorgios Papayiannis
Georgios Papayiannis
Phoebe KoundouriPhoebe Koundouri
Phoebe Koundouri
AVAchilleas Vassilopoulos
Achilleas Vassilopoulos
AYAthanasios Yannacopoulos
Athanasios Yannacopoulos
Food security is a key issue in sustainability studies. In this work, a general framework for providing detailed probabilistic socioeconomic scenarios as well as predictions concerning food security is proposed. Our methodology builds (a) on the Bayesian probabilistic version of world population prediction model and (b) on the dependencies of food needs and food system capacities on key drivers, such as population, gross domestic product (GDP) and other socioeconomic and climate indicators. In this perspective, the concept of the recently developed convex risk measures involving model uncertainty is employed for the construction of a risk assessment framework in the context of food security. The proposed method provides within and across the various probabilistic scenarios predictions and evaluations for food security risk. Our methodology is illustrated by studying food security and quantifying the occurring risk in Egypt and Ethiopia up to the year 2050, in the combined context of the Shared Socioeconomic Pathways (SSPs) and the Representative Concentration Pathways (RCPs).

1 September 2023
Verified
Book Chapter
Closed access
PDF file
Phoebe KoundouriPhoebe Koundouri
Phoebe Koundouri
GPGeorgios Papayiannis
Georgios Papayiannis
AYA. N. Yannacopoulos
A. N. Yannacopoulos