Georgios-Fivos Sargentis

Laboratory Teaching Staff, Civil Engineer, Dr. Engineer
G.-F.Sargentis@itia.ntua.gr
+30-2107722586
http://www.itia.ntua.gr/~fivos/

Participation in research projects

Participation as Researcher

  1. Maintenance, upgrading and extension of the Decision Support System for the management of the Athens water resource system
  2. Investigation of scenarios for the management and protection of the quality of the Plastiras Lake

Published work

Publications in scientific journals

  1. G.-F. Sargentis, D. Koutsoyiannis, A. N. Angelakis, J. Christy, and A.A. Tsonis, Environmental determinism vs. social dynamics: Prehistorical and historical examples, World, 3 (2), 357–388, doi:10.3390/world3020020, 2022.
  2. T. Iliopoulou, P. Dimitriadis, A. Siganou, D. Markantonis, K. Moraiti, M. Nikolinakou, I. Meletopoulos, N. Mamassis, D. Koutsoyiannis, and G.-F. Sargentis, Modern use of traditional rainwater harvesting practices: An assessment of cisterns’ water supply potential in West Mani, Greece, Heritage, 5 (4), 2944–2954, doi:10.3390/heritage5040152, 2022.
  3. G.-F. Sargentis, N. D. Lagaros, G.L. Cascella, and D. Koutsoyiannis, Threats in Water–Energy–Food–Land Nexus by the 2022 Military and Economic Conflict, Land, doi:10.3390/land11091569, 2022.
  4. R. Ioannidis, G.-F. Sargentis, and D. Koutsoyiannis, Landscape design in infrastructure projects - is it an extravagance? A cost-benefit investigation of practices in dams, Landscape Research, doi:10.1080/01426397.2022.2039109, 2022.
  5. G.-F. Sargentis, E. Frangedaki, M. Chiotinis, D. Koutsoyiannis, S. Camarinopoulos, A. Camarinopoulos, and N. D. Lagaros, 3D scanning/printing: a technological stride in sculpture, Technologies, doi:10.3390/technologies10010009, 2022.
  6. D. Koutsoyiannis, and G.-F. Sargentis, Entropy and wealth, Entropy, 23 (10), 1356, doi:10.3390/e23101356, 2021.
  7. P. Dimitriadis, T. Iliopoulou, G.-F. Sargentis, and D. Koutsoyiannis, Spatial Hurst–Kolmogorov Clustering, Encyclopedia, 1 (4), 1010–1025, doi:10.3390/encyclopedia1040077, 2021.
  8. G.-F. Sargentis, P. Siamparina, G.-K. Sakki, A. Efstratiadis, M. Chiotinis, and D. Koutsoyiannis, Agricultural land or photovoltaic parks? The water–energy–food nexus and land development perspectives in the Thessaly plain, Greece, Sustainability, 13 (16), 8935, doi:10.3390/su13168935, 2021.
  9. G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, N. Mamassis, and D. Koutsoyiannis, Stratification: An entropic view of society's structure, World, 2, 153–174, doi:10.3390/world2020011, 2021.
  10. G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, and D. Koutsoyiannis, A stochastic view of varying styles in art paintings, Heritage, 4, 21, doi:10.3390/heritage4010021, 2021.
  11. G.-F. Sargentis, R. Ioannidis, T. Iliopoulou, P. Dimitriadis, and D. Koutsoyiannis, Landscape planning of infrastructure through focus points’ clustering analysis. Case study: Plastiras artificial lake (Greece), Infrastructures, 6 (1), 12, doi:10.3390/infrastructures6010012, 2021.
  12. G.-F. Sargentis, T. Iliopoulou, S. Sigourou, P. Dimitriadis, and D. Koutsoyiannis, Evolution of clustering quantified by a stochastic method — Case studies on natural and human social structures, Sustainability, 12 (19), 7972, doi:10.3390/su12197972, 2020.
  13. G.-F. Sargentis, P. Dimitriadis, R. Ioannidis, T. Iliopoulou, E. Frangedaki, and D. Koutsoyiannis, Optimal utilization of water resources for local communities in mainland Greece (case study of Karyes, Peloponnese), Procedia Manufacturing, 44, 253–260, doi:10.1016/j.promfg.2020.02.229, 2020.
  14. G.-F. Sargentis, P. Dimitriadis, and D. Koutsoyiannis, Aesthetical issues of Leonardo Da Vinci’s and Pablo Picasso’s paintings with stochastic evaluation, Heritage, 3 (2), 283–305, doi:10.3390/heritage3020017, 2020.
  15. G.-F. Sargentis, P. Dimitriadis, R. Ioannidis, T. Iliopoulou, and D. Koutsoyiannis, Stochastic evaluation of landscapes transformed by renewable energy installations and civil works, Energies, 12 (4), 2817, doi:10.3390/en12142817, 2019.
  16. G.-F. Sargentis, R. Ioannidis, G. Karakatsanis, S. Sigourou, N. D. Lagaros, and D. Koutsoyiannis, The development of the Athens water supply system and inferences for optimizing the scale of water infrastructures, Sustainability, 11 (9), 2657, doi:10.3390/su11092657, 2019.
  17. K. Hadjibiros, A. Katsiri, A. Andreadakis, D. Koutsoyiannis, A. Stamou, A. Christofides, A. Efstratiadis, and G.-F. Sargentis, Multi-criteria reservoir water management, Global Network for Environmental Science and Technology, 7 (3), 386–394, doi:10.30955/gnj.000394, 2005.
  18. A. Christofides, A. Efstratiadis, D. Koutsoyiannis, G.-F. Sargentis, and K. Hadjibiros, Resolving conflicting objectives in the management of the Plastiras Lake: can we quantify beauty?, Hydrology and Earth System Sciences, 9 (5), 507–515, doi:10.5194/hess-9-507-2005, 2005.

Book chapters and fully evaluated conference publications

  1. G.-F. Sargentis, R. Ioannidis, M. Chiotinis, P. Dimitriadis, and D. Koutsoyiannis, Aesthetical issues with stochastic evaluation, Data Analytics for Cultural Heritage, edited by A. Belhi, A. Bouras, A.K. Al-Ali, and A.H. Sadka, doi:10.1007/978-3-030-66777-1_8, Springer, 2021.
  2. G.-F. Sargentis, K. Hadjibiros, and A. Christofides, Plastiras lake: the impact of water level on the aesthetic value of landscape, Proceedings of the 9th International Conference on Environmental Science and Technology (9CEST), Rhodes, B, 817–824, Department of Environmental Studies, University of the Aegean, 2005.
  3. K. Hadjibiros, A. Katsiri, A. Andreadakis, D. Koutsoyiannis, A. Stamou, A. Christofides, A. Efstratiadis, and G.-F. Sargentis, Multi-criteria reservoir water management, Proceedings of the 9th International Conference on Environmental Science and Technology (9CEST), Rhodes, A, 535–543, Department of Environmental Studies, University of the Aegean, 2005.
  4. K. Hadjibiros, D. Koutsoyiannis, A. Katsiri, A. Stamou, A. Andreadakis, G.-F. Sargentis, A. Christofides, A. Efstratiadis, and A. Valassopoulos, Management of water quality of the Plastiras reservoir, 4th International Conference on Reservoir Limnology and Water Quality, Ceske Budejovice, Czech Republic, doi:10.13140/RG.2.1.4872.4723, 2002.

Conference publications and presentations with evaluation of abstract

  1. D. Dimitrakopoulou, R. Ioannidis, G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, E. Chardavellas, S. Vavoulogiannis, N. Mamassis, and D. Koutsoyiannis, Social uncertainty in flood risk: field research, citizens’ engagement, institutions' collaboration, IAHS 100th Anniversary – 11th IAHS-AISH Scientific Assembly 2022, Montpellier, France, IAHS2022-351, International Association of Hydrological Sciences, 2022.
  2. G.-F. Sargentis, I. Meletopoulos, T. Iliopoulou, P. Dimitriadis, E. Chardavellas, D. Dimitrakopoulou, A. Siganou, D. Markantonis, K. Moraiti, K. Kouros, M. Nikolinakou, and D. Koutsoyiannis, Modelling water needs; from past to present. Case study: The Municipality of Western Mani, IAHS 100th Anniversary – 11th IAHS-AISH Scientific Assembly 2022, Montpellier, France, IAHS2022-400, International Association of Hydrological Sciences, 2022.
  3. P. Dimitriadis, T. Iliopoulou, G.-F. Sargentis, and D. Koutsoyiannis, Spatial and temporal long-range dependence in the scale domain, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-13051, doi:10.5194/egusphere-egu22-13051, European Geosciences Union, 2022.
  4. D. Markantonis, A. Siganou, K. Moraiti, M. Nikolinakou, G.-F. Sargentis, P. Dimitriadis, M. Chiotinis, T. Iliopoulou, N. Mamassis, and D. Koutsoyiannis, Determining optimal scale of water infrastructure considering economical aspects with stochastic evaluation – Case study at the Municipality of Western Mani, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3039, doi:10.5194/egusphere-egu22-3039, European Geosciences Union, 2022.
  5. K. Moraiti, D. Markantonis, M. Nikolinakou, A. Siganou, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, I. Meletopoulos, N. Mamassis, and D. Koutsoyiannis, Optimizing water infrastructure solutions for small-scale distributed settlements – Case study at the Municipality of Western Mani., EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3055, doi:10.5194/egusphere-egu22-3055, European Geosciences Union, 2022.
  6. M. Nikolinakou, K. Moraiti, A. Siganou, D. Markantonis, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, I. Meletopoulos, N. Mamassis, and D. Koutsoyiannis, Investigating the water supply potential of traditional rainwater harvesting techniques used – A case study for the Municipality of Western Mani, EGU General Assembly 2022, Vienna, Austria & Online, European Geosciences Union, 2022.
  7. A. Siganou, M. Nikolinakou, D. Markantonis, K. Moraiti, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, M. Chiotinis, N. Mamassis, and D. Koutsoyiannis, Stochastic simulation of hydrological timeseries for data scarce regions - Case study at the Municipality of Western Mani, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3086, doi:10.5194/egusphere-egu22-3086, European Geosciences Union, 2022.
  8. I. Arvanitidis, Μ. Diamanta, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, and D. Koutsoyiannis, Identifying links between hydroclimatic variability and economical components using stochastic methods, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-5944, doi:10.5194/egusphere-egu22-5944, European Geosciences Union, 2022.
  9. S. Vrettou, A. Trompouki, T. Iliopoulou, G.-F. Sargentis, P. Dimitriadis, and D. Koutsoyiannis, Investigation of stochastic similarities between wind and waves and their impact on offshore structures, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3082, doi:10.5194/egusphere-egu22-3082, European Geosciences Union, 2022.
  10. A. Trompouki, S. Vrettou, G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, and D. Koutsoyiannis, Investigation of the spatial correlation structure of 2-D wave fields at the Aegean Sea, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3083, doi:10.5194/egusphere-egu22-3083, European Geosciences Union, 2022.
  11. E. Manta, R. Ioannidis, G.-F. Sargentis, and A. Efstratiadis, Aesthetic evaluation of wind turbines in stochastic setting: Case study of Tinos island, Greece, European Geosciences Union General Assembly 2020, Geophysical Research Abstracts, Vol. 22, Vienna, EGU2020-5484, doi:10.5194/egusphere-egu2020-5484, 2020.
  12. E. Frangedaki, and G.-F. Sargentis, Optimizing engineering aspects of earth constructions.The earth as "common" material., European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-11412-1, European Geosciences Union, 2019.
  13. G.-F. Sargentis, E. Frangedaki, P. Dimitriadis, and D. Koutsoyiannis, Development of a web platform of knowledge exchange for optimal selection of building materials based on ecological criteria, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-10395, European Geosciences Union, 2019.
  14. Μ. Sako, E. Tsoli, R. Ioannidis, E. Frangedaki, G.-F. Sargentis, and D. Koutsoyiannis, Optimizing the size of Hilarion dam with technical, economical and environmental parameters, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-15297, European Geosciences Union, 2019.
  15. R. Ioannidis, P. Dimitriadis, G.-F. Sargentis, E. Frangedaki, T. Iliopoulou, and D. Koutsoyiannis, Stochastic similarities between hydrometeorogical and art processes for optimizing architecture and landscape aesthetic parameters, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-11403, European Geosciences Union, 2019.
  16. G.-F. Sargentis, R. Ioannidis, G. Karakatsanis, and D. Koutsoyiannis, The scale of infrastructures as a social decision. Case study: dams in Greece, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-17082, European Geosciences Union, 2018.
  17. G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, and D. Koutsoyiannis, Stochastic investigation of the Hurst-Kolmogorov behaviour in arts, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-17740-1, European Geosciences Union, 2018.
  18. A. Efstratiadis, D. Koutsoyiannis, K. Hadjibiros, A. Andreadakis, A. Stamou, A. Katsiri, G.-F. Sargentis, and A. Christofides, A multicriteria approach for the sustainable management of the Plastiras reservoir, Greece, EGS-AGU-EUG Joint Assembly, Geophysical Research Abstracts, Vol. 5, Nice, doi:10.13140/RG.2.2.23631.48801, European Geophysical Society, 2003.
  19. S. Sigourou, V. Pagana, P. Dimitriadis, A. Tsouni, T. Iliopoulou, G.-F. Sargentis, R. Ioannidis, E. Chardavellas, D. Dimitrakopoulou, N. Mamassis, C. Contoes, and D. Koutsoyiannis, Flood risk assessment in the region of Attica, 9th International Conference on Civil Protection & New Technologies - Safe Thessaloniki 2022, Thessaloniki, Greece, September 2022.
  20. S. Sigourou, V. Pagana, P. Dimitriadis, A. Tsouni, T. Iliopoulou, G.-F. Sargentis, R. Ioannidis, E. Chardavellas, D. Dimitrakopoulou, N. Mamassis, C. Contoes, and D. Koutsoyiannis, Proposed methodology for urban flood-risk assessment at river-basin level: the case study of the Pikrodafni river basin in Athens, Greece, Global Flood Partnership 2022 Annual Meeting, Leeds, UK, September 2022.

Presentations and publications in workshops

  1. A. Tsouni, S. Sigourou, V. Pagana, D. Koutsoyiannis, N. Mamassis, A. Koukouvinos, P. Dimitriadis, T. Iliopoulou, G.-F. Sargentis, R. Ioannidis, D. Dimitrakopoulou, E. Chardavellas, S. Vavoulogiannis, and V. Kyriakouli, Flood risk assessment in the Pikrodafni basin, Presentation of results for the 1st Phase of the Program Agreement between Attica Regional Authority and NOA, Athens, National Observatory of Athens, 2022.

Various publications

  1. G.-F. Sargentis, and N. Mamassis, [No English title available], 75–80, 2021.

Educational notes

  1. D. Koutsoyiannis, M. Pantazidou, N. Mamassis, G.-F. Sargentis, P. Thanopoulos, S. Lampropoulos, D Vamvatsikos, and K. Hadjibiros, Lecture Notes for the Laboratory on Humanities, School of Civil Engineering – National Technical University of Athens, Athens, 2020.
  2. G.-F. Sargentis, Lecture notes on Environmental Impacts: The aesthetic element at dams, 28 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, October 2019.
  3. A. Efstratiadis, G.-F. Sargentis, and N. Mamassis, Lecture notes on Environmental Impacts: Analysis of environmental impacts from large hydraulic structures, 37 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, October 2019.
  4. A. Christofides, A. Efstratiadis, and G.-F. Sargentis, Presentation of the research project "Investigation of scenarios for the management and protection of the quality of the Plastiras Lake", 79 pages, 1 April 2003.

Academic works

  1. G.-F. Sargentis, Issues of Prosperity: Stochastic evaluation of data related to environment, infrastructures, economy and society, PhD thesis, Department of Water Resources and Environmental Engineering – National Technical University of Athens, June 2022.
  2. G.-F. Sargentis, The esthetic element in water, hydraulic works and dams, Diploma thesis, Department of Water Resources, Hydraulic and Maritime Engineering – National Technical University of Athens, Athens, 1998.

Research reports

  1. K. Hadjibiros, D. Koutsoyiannis, A. Andreadakis, A. Katsiri, A. Stamou, A. Valassopoulos, A. Efstratiadis, I. Katsiris, M. Kapetanaki, A. Koukouvinos, N. Mamassis, K. Noutsopoulos, G.-F. Sargentis, and A. Christofides, Overview report, Investigation of scenarios for the management and protection of the quality of the Plastiras Lake, Report 1, 23 pages, Department of Water Resources, Hydraulic and Maritime Engineering – National Technical University of Athens, Athens, March 2002.
  2. G.-F. Sargentis, and A. Christofides, The landscape, Investigation of scenarios for the management and protection of the quality of the Plastiras Lake, Report 4, 73 pages, Department of Water Resources, Hydraulic and Maritime Engineering – National Technical University of Athens, Athens, March 2002.

Details on research projects

Participation as Researcher

  1. Maintenance, upgrading and extension of the Decision Support System for the management of the Athens water resource system

    Duration: October 2008–November 2011

    Budget: €72 000

    Project director: N. Mamassis

    Principal investigator: D. Koutsoyiannis

    This research project includes the maintenance, upgrading and extension of the Decision Support System that developed by NTUA for EYDAP in the framework of the research project “Updating of the supervision and management of the water resources’ system for the water supply of the Athens’ metropolitan area”. The project is consisted of the following parts: (a) Upgrading of the Data Base, (b)Upgrading and extension of hydrometeorological network, (c) upgrading of the hydrometeorological data process software, (d) upgrading and extension of the Hydronomeas software, (e) hydrological data analysis and (f) support to the preparation of the annual master plans

  1. Investigation of scenarios for the management and protection of the quality of the Plastiras Lake

    Duration: May 2001–January 2002

    Commissioned by:

    1. Prefectural Government of Karditsa
    2. Municipality of Karditsa

    Contractor: Department of Water Resources, Hydraulic and Maritime Engineering

    Project director: K. Hadjibiros

    Principal investigator: D. Koutsoyiannis

    To protect the Plastiras Lake, a high quality of the natural landscape and a satisfactory water quality must be ensured, the conflicting water uses and demands must be arranged and effective water management practices must be established. To this aim, the hydrology of the catchment is investigated, the geographical, meteorological and water power data are collected and processed, the water balance is studied and a stochastic model is constructed to support the study of alternative management scenarios. In addition, an analysis of the natural landscape is performed and the negative influences (e.g. dead tries) are determined and quantified using GIS. Furthermore, the water quality parameters are evaluated, the water quality state is assessed, the quantitative targets are determined, the pollution sources are identified and measures for the reduction of pollution are studied using a hydrodynamic model with emphasis on the nutrient status. Based on the results of these analyses, scenarios of safe water release are suggested.

Published work in detail

Publications in scientific journals

  1. G.-F. Sargentis, D. Koutsoyiannis, A. N. Angelakis, J. Christy, and A.A. Tsonis, Environmental determinism vs. social dynamics: Prehistorical and historical examples, World, 3 (2), 357–388, doi:10.3390/world3020020, 2022.

    Environmental determinism is often used to explain past social collapses and to predict the future of modern human societies. We assess the availability of natural resources and the resulting carrying capacity (a basic concept of environmental determinism) through a toy model based on Hurst–Kolmogorov dynamics. We also highlight the role of social cohesion, and we evaluate it from an entropic viewpoint. Furthermore, we make the case that, when it comes to the demise of civilizations, while environmental influences may be in the mix, social dynamics is the main driver behind their decline and eventual collapse. We examine several prehistorical and historical cases of civilization collapse, the most characteristic being that of the Minoan civilization, whose disappearance c. 1100 BC has fostered several causative hypotheses. In general, we note that these hypotheses are based on catastrophic environmental causes, which nevertheless occurred a few hundred years before the collapse of Minoans. Specifically, around 1500 BC, Minoans managed to overpass many environmental adversities. As we have not found justified reasons based on the environmental determinism for when the collapse occurred (around 1100 BC), we hypothesize a possible transformation of the Minoans’ social structure as the cause of the collapse.

    Full text: http://www.itia.ntua.gr/en/getfile/2247/1/documents/world-03-00020.pdf (10291 KB)

  1. T. Iliopoulou, P. Dimitriadis, A. Siganou, D. Markantonis, K. Moraiti, M. Nikolinakou, I. Meletopoulos, N. Mamassis, D. Koutsoyiannis, and G.-F. Sargentis, Modern use of traditional rainwater harvesting practices: An assessment of cisterns’ water supply potential in West Mani, Greece, Heritage, 5 (4), 2944–2954, doi:10.3390/heritage5040152, 2022.

    Water has always been a driver of human civilization. The first human civilizations thrived in places with an abundance of water, typically nearby large rivers as the Tigris–Euphrates, Yang Che and Nile. The invention and construction of hydraulic infrastructure came only later, in prehistoric times, triggered by the expansion of humanity in water-scarce areas. The ancient Greeks invented impressive hydraulic works and small-scale structures, some of which, such as cisterns, were still fully operational until the 20th century. We present a model that explains the use of cisterns in the water-scarce area of West Mani, which allows us to assess the potential of this traditional rainfall harvesting practice to support the modern water supply needs. To assess the system’s reliability, we employ a long-term simulation of a typical cistern system, using synthetic rainfall series from a stochastic model, and assuming variable water demand on a monthly scale. We show that a proper restoration of the cisterns could be sustainable as a complementary water supply source, decreasing the area’s drinking water cost and increasing the locals’ resilience against water shortages. In addition, we highlight the links between the area’s hydroclimate and its history and discuss the cultural merits of reviving and preserving this ancient, long practice.

    Full text: http://www.itia.ntua.gr/en/getfile/2243/1/documents/heritage-05-00152-v3.pdf (4196 KB)

  1. G.-F. Sargentis, N. D. Lagaros, G.L. Cascella, and D. Koutsoyiannis, Threats in Water–Energy–Food–Land Nexus by the 2022 Military and Economic Conflict, Land, doi:10.3390/land11091569, 2022.

    The formation of societies is based on the dynamics of spatial clustering, which optimizes economies of scale in the management of the water–energy–food (WEF) nexus. Energy and food are determinant measures of prosperity. Using the WEF nexus as an indicator, we evaluate the social impacts of the current (2022) conflict and in particular the economic sanctions on Russia. As Russia and Ukraine are major global suppliers of energy sources, food, and fertilizers, new threats arise by their limitations and the rally of prices. By analyzing related data, we show the dramatic effects on society, and we note that cities, which depend on a wider area for energy and food supplies, are extremely vulnerable. This problem was substantially worsened due to the large-scale urbanization in recent decades, which increased the distance from food sources. We conjecture that the Western elites’ decision to sanction Russia dramatically transformed the global WEF equilibrium, which could probably lead to the collapse of social cohesion.

    Full text: http://www.itia.ntua.gr/en/getfile/2239/1/documents/land-11-01569-v2.pdf (4700 KB)

  1. R. Ioannidis, G.-F. Sargentis, and D. Koutsoyiannis, Landscape design in infrastructure projects - is it an extravagance? A cost-benefit investigation of practices in dams, Landscape Research, doi:10.1080/01426397.2022.2039109, 2022.

    Landscape design of major civil infrastructure works has often been undermined as a policy requirement or been neglected in practice. We investigate whether this is justified by technical challenges, high costs or proven lack of utility of landscape design of infrastructure, focussing on dam-design practice. Initially, we investigate global practice and identify 56 cases of dams in which landscape or architectural treatment has been applied. We then create a typology of utilised design techniques and investigate their contribution to improving landscape quality perception through literature review and through the analysis of photograph upload densities in geotagged photography databases. Finally, we investigate costs of landscape works, analysing three dam projects in detail. The results demonstrate that landscape design of civil infrastructure (a) improves landscape quality perception of infrastructures’ landscapes and (b) that its implementation can be both economically and technically feasible, especially if existing knowledge from best practices is utilised.

    Additional material:

  1. G.-F. Sargentis, E. Frangedaki, M. Chiotinis, D. Koutsoyiannis, S. Camarinopoulos, A. Camarinopoulos, and N. D. Lagaros, 3D scanning/printing: a technological stride in sculpture, Technologies, doi:10.3390/technologies10010009, 2022.

    The creation of innovative tools, objects and artifacts that introduce abstract ideas in the real world is a necessary step for the evolution process and characterize the creative capacity of civilization. Sculpture is based on the available technology for its creation process and is strongly related to the level of technological sophistication of each era. This paper analyzes the evolution of basic sculpture techniques (carving, lost-wax casting and 3D scanning/printing), and their importance as a culture footprint. It also presents and evaluates the added creative capacities of each technological step and the different methods of 3D scanning/printing concerning sculpture. It is also an attempt to define the term “material poetics”, which is connected to sculpture artifacts. We conclude that 3D scanning/printing is an important sign of civilization, although artifacts lose a part of material poetics with additive manufacturing. Subsequently, there are various causes of the destruction of sculptures, leaving a hole in the history of art. Finally, this paper showcases the importance of 3D scanning/printing in salvaging cultural heritage, as it has radically altered the way we “backup” objects.

    Full text: http://www.itia.ntua.gr/en/getfile/2175/1/documents/technologies-10-00009-v3.pdf (13152 KB)

  1. D. Koutsoyiannis, and G.-F. Sargentis, Entropy and wealth, Entropy, 23 (10), 1356, doi:10.3390/e23101356, 2021.

    While entropy was introduced in the second half of the 19th century in the international vocabulary as a scientific term, in the 20th century it became common in colloquial use. Popular imagination has loaded “entropy” with almost every negative quality in the universe, in life and in society, with a dominant meaning of disorder and disorganization. Exploring the history of the term and many different approaches to it, we show that entropy has a universal stochastic definition, which is not disorder. Hence, we contend that entropy should be used as a mathematical (stochastic) concept as rigorously as possible, free of metaphoric meanings. The accompanying principle of maximum entropy, which lies behind the Second Law, gives explanatory and inferential power to the concept, and promotes entropy as the mother of creativity and evolution. As the social sciences are often contaminated by subjectivity and ideological influences, we try to explore whether maximum entropy, applied to the distribution of a wealth-related variable, namely annual income, can give an objective description. Using publicly available income data, we show that income distribution is consistent with the principle of maximum entropy. The increase in entropy is associated to increases in society’s wealth, yet a standardized form of entropy can be used to quantify inequality. Historically, technology has played a major role in the development of and increase in the entropy of income. Such findings are contrary to the theory of ecological economics and other theories that use the term entropy in a Malthusian perspective.

    Remarks:

    The extended summary is also posted in https://clintel.org/entropy-and-wealth/

    Full text: http://www.itia.ntua.gr/en/getfile/2150/1/documents/entropy-23-01356-v3.pdf (7617 KB)

    Additional material:

  1. P. Dimitriadis, T. Iliopoulou, G.-F. Sargentis, and D. Koutsoyiannis, Spatial Hurst–Kolmogorov Clustering, Encyclopedia, 1 (4), 1010–1025, doi:10.3390/encyclopedia1040077, 2021.

    The stochastic analysis in the scale domain (instead of the traditional lag or frequency domains) is introduced as a robust means to identify, model and simulate the Hurst–Kolmogorov (HK) dynamics, ranging from small (fractal) to large scales exhibiting the clustering behavior (else known as the Hurst phenomenon or long-range dependence). The HK clustering is an attribute of a multidimensional (1D, 2D, etc.) spatio-temporal stationary stochastic process with an arbitrary marginal distribution function, and a fractal behavior on small spatio-temporal scales of the dependence structure and a power-type on large scales, yielding a high probability of low- or high-magnitude events to group together in space and time. This behavior is preferably analyzed through the second-order statistics, and in the scale domain, by the stochastic metric of the climacogram, i.e., the variance of the averaged spatio-temporal process vs. spatio-temporal scale.

  1. G.-F. Sargentis, P. Siamparina, G.-K. Sakki, A. Efstratiadis, M. Chiotinis, and D. Koutsoyiannis, Agricultural land or photovoltaic parks? The water–energy–food nexus and land development perspectives in the Thessaly plain, Greece, Sustainability, 13 (16), 8935, doi:10.3390/su13168935, 2021.

    Water, energy, land, and food are vital elements with multiple interactions. In this context, the concept of a water–energy–food (WEF) nexus was manifested as a natural resource management approach, aiming at promoting sustainable development at the international, national, or local level and eliminating the negative effects that result from the use of each of the four resources against the other three. At the same time, the transition to green energy through the application of renewable energy technologies is changing and perplexing the relationships between the constituent elements of the nexus, introducing new conflicts, particularly related to land use for energy production vs. food. Specifically, one of the most widespread “green” technologies is photovoltaic (PV) solar energy, now being the third foremost renewable energy source in terms of global installed capacity. However, the growing development of PV systems results in ever expanding occupation of agricultural lands, which are most advantageous for siting PV parks. Using as study area the Thessaly Plain, the largest agricultural area in Greece, we investigate the relationship between photovoltaic power plant development and food production in an attempt to reveal both their conflicts and their synergies.

    Full text: http://www.itia.ntua.gr/en/getfile/2136/1/documents/sustainability-13-08935.pdf (2709 KB)

    See also: https://www.mdpi.com/2071-1050/13/16/8935

    Other works that reference this work (this list might be obsolete):

    1. Abouaiana, A., and A. Battisti, Multifunction land use to promote energy communities in Mediterranean region: Cases of Egypt and Italy, Land, 11(5), 673, doi:10.3390/land11050673, 2022.
    2. Reasoner, M., and A. Ghosh, Agrivoltaic engineering and layout optimization approaches in the transition to renewable energy technologies: a review, Challenges, 13(2), 43, doi:10.3390/challe13020043, 2022.
    3. Bhambare, P. S., and S. C. Vishweshwara, Design aspects of a fixed focus type Scheffler concentrator and its receiver for its utilization in thermal processing units, Energy Nexus, 7, 100103, doi:10.1016/j.nexus.2022.100103, 2022.
    4. Padilla, J., C. Toledo, and J. Abad, Enovoltaics: Symbiotic integration of photovoltaics in vineyards, Frontiers in Energy Research, 10, 1007383, doi:10.3389/fenrg.2022.1007383, 2022.
    5. Garcia, J. A., and A. Alamanos, Integrated modelling approaches for sustainable agri-economic growth and environmental improvement: Examples from Greece, Canada and Ireland, Land, 11(9), 1548, doi:10.3390/land11091548, 2022.

  1. G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, N. Mamassis, and D. Koutsoyiannis, Stratification: An entropic view of society's structure, World, 2, 153–174, doi:10.3390/world2020011, 2021.

    In human societies, we observe a wide range of types of stratification, i.e., in terms of financial class, political power, level of education, sanctity, and military force. In financial, political, and social sciences, stratification is one of the most important issues and tools as the Lorenz Curve and the Gini Coefficient have been developed to describe some of its aspects. Stratification is greatly dependent on the access of people to wealth. By “wealth”, we mean the quantified prosperity which increases the life expectancy of people. Prosperity is also connected to the water‐food‐energy nexus which is necessary for human survival. Analyzing proxies of the water‐food‐energy nexus, we suggest that the best proxy for prosperity is energy, which is closely related to Gross Domestic Product (GDP) per capita and life expectancy. In order to describe the dynamics of social stratification, we formulate an entropic view of wealth in human societies. An entropic approach to income distribution, approximated as available energy in prehistoric societies, till present‐day economies, shows that stratification can be viewed as a stochastic process subject to the principle of maximum entropy and occurring when limits to the wealth of society are set, either by the political and economic system and/or by the limits of available technology.

    Full text: http://www.itia.ntua.gr/en/getfile/2107/1/documents/world-02-00011-v3.pdf (10384 KB)

    Works that cite this document: View on Google Scholar or ResearchGate

  1. G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, and D. Koutsoyiannis, A stochastic view of varying styles in art paintings, Heritage, 4, 21, doi:10.3390/heritage4010021, 2021.

    A physical process is characterized as complex when it is difficult to analyze and explain in a simple way, and even more difficult to predict. The complexity within an art painting is expected to be high, possibly comparable to that of nature. Herein, we apply a 2D stochastic methodology to images of both portrait photography and artistic portraits, the latter belonging to different genres of art, with the aim to better understand their variability in quantitative terms. To quantify the dependence structure and variability, we estimate the Hurst parameter, which is a common dependence metric for hydrometeorological processes. We also seek connections between the identified stochastic patterns and the desideratum that each art movement aimed to express. Results show remarkable stochastic similarities between portrait paintings, linked to philosophical, cultural and theological characteristics of each period.

    Full text: http://www.itia.ntua.gr/en/getfile/2086/1/documents/heritage-04-00021.pdf (3242 KB)

    Works that cite this document: View on Google Scholar or ResearchGate

  1. G.-F. Sargentis, R. Ioannidis, T. Iliopoulou, P. Dimitriadis, and D. Koutsoyiannis, Landscape planning of infrastructure through focus points’ clustering analysis. Case study: Plastiras artificial lake (Greece), Infrastructures, 6 (1), 12, doi:10.3390/infrastructures6010012, 2021.

    Even though landscape quality is largely a subjective issue, the integration of infrastructure into landscapes has been identified as a key element of sustainability. In a spatial planning context, the landscape impacts that are generated by infrastructures are commonly quantified through visibility analysis. In this study, we develop a new method of visibility analysis and apply it in a case study of a reservoir (Plastiras dam in Greece). The methodology combines common visibility analysis with a stochastic tool for visual-impacts evaluation; points that generate high visual contrasts in landscapes are considered Focus Points (FPs) and their clustering in landscapes is analyzed trying to answer two questions: (1) How does the clustering of Focus Points (FPs) impact the aesthetic value of the landscape? (2) How can the visual impacts of these FPs be evaluated? Visual clustering is calculated utilizing a stochastic analysis of generated Zones of Theoretical Visibility. Based on the results, we argue that if the visual effect of groups of FPs is positive, then the optimal sitting of FPs should be in the direction of faint clustering, whereas if the effect is negative, the optimal sitting of FPs should be directed to intense clustering. In order to optimize the landscape integration of infrastructure, this method could be a useful analytical tool for environmental impact assessment or a monitoring tool for a project’s managing authorities. This is demonstrated through the case study of Plastiras’ reservoir, where the clustering of positively perceived FPs is found to be an overlooked attribute of its perception as a highly sustainable infrastructure project.

    Full text: http://www.itia.ntua.gr/en/getfile/2083/1/documents/infrastructures-06-00012-v2.pdf (5634 KB)

    Works that cite this document: View on Google Scholar or ResearchGate

  1. G.-F. Sargentis, T. Iliopoulou, S. Sigourou, P. Dimitriadis, and D. Koutsoyiannis, Evolution of clustering quantified by a stochastic method — Case studies on natural and human social structures, Sustainability, 12 (19), 7972, doi:10.3390/su12197972, 2020.

    Clustering structures appearing from small to large scales are ubiquitous in the physical world. Interestingly, clustering structures are omnipresent in human history too, ranging from the mere organization of life in societies (e.g., urbanization) to the development of large-scale infrastructure and policies for meeting organizational needs. Indeed, in its struggle for survival and progress, mankind has perpetually sought the benefits of unions. At the same time, it is acknowledged that as the scale of the projects grows, the cost of the delivered products is reduced while their quantities are maximized. Thus, large-scale infrastructures and policies are considered advantageous and are constantly being pursued at even great scales. This work develops a general method to quantify the temporal evolution of clustering, using a stochastic computational tool called 2D-C, which is applicable for the study of both natural and human social spatial structures. As case studies, the evolution of the structure of the universe, of ecosystems and of human clustering structures such as urbanization, are investigated using novel sources of spatial information. Results suggest the clear existence both of periods of clustering and declustering in the natural world and in the human social structures; yet clustering is the general trend. In view of the ongoing COVID-19 pandemic, societal challenges arising from large-scale clustering structures are discussed.

    Full text: http://www.itia.ntua.gr/en/getfile/2066/1/documents/sustainability-12-07972.pdf (8123 KB)

    See also: https://www.mdpi.com/2071-1050/12/19/7972/htm

    Works that cite this document: View on Google Scholar or ResearchGate

  1. G.-F. Sargentis, P. Dimitriadis, R. Ioannidis, T. Iliopoulou, E. Frangedaki, and D. Koutsoyiannis, Optimal utilization of water resources for local communities in mainland Greece (case study of Karyes, Peloponnese), Procedia Manufacturing, 44, 253–260, doi:10.1016/j.promfg.2020.02.229, 2020.

    Water is the basis of our civilization and the development of society is intertwined with the exploitation of water resources in various scales, from a well dug to irrigate a garden, to a large dam providing water and energy for a large area. However, for remote mountainous areas, intermittent natural water resources and high seasonal demand the above tasks become challenging. Here we discuss various alternative management options and appropriate solutions on how to exploit water resources meeting the above restrictions under limited infrastructure budgets. As a case study we examine the area of Karyes in Peloponnese that meets the above criteria, exploring various solutions to satisfy the water demand.

    Full text: http://www.itia.ntua.gr/en/getfile/2047/1/documents/1-s2.0-S2351978920308167-main.pdf (1660 KB)

    Works that cite this document: View on Google Scholar or ResearchGate

  1. G.-F. Sargentis, P. Dimitriadis, and D. Koutsoyiannis, Aesthetical issues of Leonardo Da Vinci’s and Pablo Picasso’s paintings with stochastic evaluation, Heritage, 3 (2), 283–305, doi:10.3390/heritage3020017, 2020.

    A physical process is characterized as complex when it is difficult to analyze or explain in a simple way. The complexity within an art painting is expected to be high, possibly comparable to that of nature. Therefore, constructions of artists (e.g., paintings, music, literature, etc.) are expected to be also of high complexity since they are produced by numerous human (e.g., logic, instinct, emotions, etc.) and non-human (e.g., quality of paints, paper, tools, etc.) processes interacting with each other in a complex manner. The result of the interaction among various processes is not a white-noise behavior, but one where clusters of high or low values of quantified attributes appear in a non-predictive manner, thus highly increasing the uncertainty and the variability. In this work, we analyze stochastic patterns in terms of the dependence structure of art paintings of Da Vinci and Picasso with a stochastic 2D tool and investigate the similarities or differences among the artworks.

    Full text: http://www.itia.ntua.gr/en/getfile/2043/1/documents/heritage-03-00017.pdf (9130 KB)

    Works that cite this document: View on Google Scholar or ResearchGate

  1. G.-F. Sargentis, P. Dimitriadis, R. Ioannidis, T. Iliopoulou, and D. Koutsoyiannis, Stochastic evaluation of landscapes transformed by renewable energy installations and civil works, Energies, 12 (4), 2817, doi:10.3390/en12142817, 2019.

    Renewable energy (RE) installations and civil works are beneficial in terms of sustainability, but a considerable amount of space in the landscape is required in order to harness this energy. In contemporary environmental theory the landscape is considered an environmental parameter and the transformation of the landscape by RE works has received increasing attention by the scientific community and affected societies. This research develops a novel computational stochastic tool the 2D Climacogram (2D-C) that allows the analysis and comparison of images of landscapes, both original and transformed by RE works. This is achieved by a variability characterization of the grayscale intensity of 2D images. A benchmark analysis is performed for art paintings in order to evaluate the properties of the 2D-C for image analysis, and the change in variability among images. Extensive applications are performed for landscapes transformed by RE works. Results show that the 2D-C is able to quantify the changes in variability of the image features, which may prove useful in the landscape impact assessment of large-scale engineering works.

    Full text: http://www.itia.ntua.gr/en/getfile/1984/1/documents/energies-12-02817.pdf (2772 KB)

    Additional material:

    Works that cite this document: View on Google Scholar or ResearchGate

    Other works that reference this work (this list might be obsolete):

    1. Ding, L., Q. Li, J. Tang, J. Wang, and X. Chen, Linking land use metrics measured in aquatic-terrestrial interfaces to water quality of reservoir-based water sources in Eastern China, Sustainability, 11(18), 4860, doi:10.3390/su11184860, 2019.

  1. G.-F. Sargentis, R. Ioannidis, G. Karakatsanis, S. Sigourou, N. D. Lagaros, and D. Koutsoyiannis, The development of the Athens water supply system and inferences for optimizing the scale of water infrastructures, Sustainability, 11 (9), 2657, doi:10.3390/su11092657, 2019.

    Modern organized societies require robust infrastructures, among which hydraulic projects, such as water supply and drainage systems, are most important, particularly in water-scarce areas. Athens is a unique example because it is a big city (population 3.7 million) located in a very dry area. In order to support the development of the city, large hydraulic projects had to be constructed during its history and, as a result, Athens currently has one of the largest water supply systems in the world. Could Athenians choose smaller scale infrastructures instead? Analyzing social, technical and economical historical data, we can see that large capital investments were required. In order to evaluate these investments this paper presents a technical summary of the development. An economic analysis displays historical values of these investments in present monetary values. The cost of existing infrastructure is compared to the cost of constructing smaller reservoirs and a model is created to correlate the price of water and the cost of water storage with the size of reservoirs. In particular, if more and smaller reservoirs were built instead of the large existing ones, the cost of the water would significantly increase, as illustrated by modelling the cost using local data.

    Full text: http://www.itia.ntua.gr/en/getfile/1970/1/documents/sustainability-11-02657-v3.pdf (6450 KB)

    See also: https://www.mdpi.com/2071-1050/11/9/2657

    Works that cite this document: View on Google Scholar or ResearchGate

  1. K. Hadjibiros, A. Katsiri, A. Andreadakis, D. Koutsoyiannis, A. Stamou, A. Christofides, A. Efstratiadis, and G.-F. Sargentis, Multi-criteria reservoir water management, Global Network for Environmental Science and Technology, 7 (3), 386–394, doi:10.30955/gnj.000394, 2005.

    The Plastiras dam was constructed in the late 1950s mainly for electric power production, but it has also partially covered irrigation needs and water supply of the plain of Thessaly. Later, the site has been designated as an environment conservation zone because of ecological and landscape values, while tourist activities have been developed around the reservoir. Irrigation of agricultural land, hydroelectric production, drinking water supply, tourism, ecosystem water quality and scenery conservation have evidently been conflicting targets for many years. Good management would require a multi-criteria decision making. Historical data show that the irregular water release has resulted in a great annual fluctuation of the reservoir water level. This situation could be improved by a rational management of abstractions. Apparently, higher release leads simultaneously to more power production and to irrigation of a larger agricultural land. Moreover, demands for electricity and for irrigation are partially competing to each other, due to different optimal time schedules of releases. On the other hand, higher water release leads to lower water level in the reservoir and, therefore, it decreases the beauty of the scenery and deteriorates the trophic state of the lake. Such degradation affects the tourist potential as well as the quality of drinking water supplied by the reservoir. A multi-criteria approach uses different scenarios for the minimum permissible water level of the reservoir, if a constant annual release is applied. The minimum level concept is a simple and functional tool, because it is understood by people, easily certified and incorporated into regulations. The quantity of water that would be yearly available is a function of the minimum level allowed. The water quality depends upon the trophic state of the lake, mainly the concentration of chlorophyll-a, which determines the state of eutrophication and is estimated by water quality simulation models, taking into account pollutant loads such as nitrogen and phosphorus. The value of the landscape is much depending on the water level of the lake, because for lower levels a dead-zone appears between the surface of the water and the surrounding vegetation. When this dead zone is large, it seems lifeless and the lake appears partially empty. Quantification of this visual effect is not easy, but it is possible to establish a correspondence between the aesthetic assessment of the scenery and the minimum allowed reservoir level. Using results from hydrological analysis, water quality models and landscape evaluation, it seems possible to construct a multi-criteria table with different criteria described against alternatives and with a plot of three relative indices against the minimum level allowed. However, decision making has to take into account the fact that comparison or merging of indices corresponding to different criteria analysis encompasses a degree of arbitrariness. More objective decisions would be possible if different benefits and costs were measured in a common unit. Moreover, management will be sensitive to different social pressures.

    Related works:

    • [18] Publication focused on the logic of multicriteria decisions.

    Full text: http://www.itia.ntua.gr/en/getfile/704/1/documents/2006GnestPlastiras.pdf (114 KB)

    Additional material:

    See also: http://www.gnest.org/Journal/Vol7_No3.htm

    Works that cite this document: View on Google Scholar or ResearchGate

    Other works that reference this work (this list might be obsolete):

    1. #Sarkar, A., & M. Chakrabarti, Feasibility of corridor between Singhalilla National Park and Senchal Wild Life Sanctuary: a study of five villages between Poobong and 14th Mile Village, Parks, Peace and Partnerships Conf., Waterton, Canada, 2007
    2. Chakrabarti, M., and S. K. Datta, Evolving an effective management information system to monitor co-management of forests, Economic and Political Weekly, 44(18), 53-60, 2009.
    3. Vassoney, E., A. M. Mochet, and C. Comoglio, Use of multicriteria analysis (MCA) for sustainable hydropower planning and management, Journal of Environmental Management, 196, 48–55, doi:10.1016/j.jenvman.2017.02.067, 2017.
    4. Duc, D. X., L. D. Hai, and D. H. Tuan, Self-cleaning ability of pollutants containing nitrogen and phosphorus transformed into NH4+, NO2-, NO3-, PO43-, of SonLa hydropower reservoir, VNU Journal of Science: Earth and Environmental Sciences, 36(3), 12-24, doi:10.25073/2588-1094/vnuees.4510, 2020.

  1. A. Christofides, A. Efstratiadis, D. Koutsoyiannis, G.-F. Sargentis, and K. Hadjibiros, Resolving conflicting objectives in the management of the Plastiras Lake: can we quantify beauty?, Hydrology and Earth System Sciences, 9 (5), 507–515, doi:10.5194/hess-9-507-2005, 2005.

    The possible water management of the Plastiras Lake, an artificial reservoir in central Greece, is examined. The lake and surrounding landscape are aesthetically degraded when the water level drops, and the requirement of maintaining a high quality of the scenery constitutes one of the several conflicting water uses, the other ones being irrigation, water supply, and power production. This environmental water use, and, to a lesser extent, the requirement for adequate water quality, results in constraining the annual release. Thus, the allowed fluctuation of reservoir stage is not defined by the physical and technical characteristics of the reservoir, but by a multi-criteria decision, the three criteria being maximising water release, ensuring adequate water quality, and maintaining a high quality of the natural landscape. Each of these criteria is analyzed separately. The results are then put together in a multicriterion tableau, which helps understand the implications of the possible alternative decisions. Several conflict resolution methods are overviewed, namely willingness to pay, hedonic prices, and multi-criteria decision analysis. All these methods attempt to quantify non-quantifiable qualities, and it is concluded that they don't necessarily offer any advantage over merely making a choice based on understanding.

    Remarks:

    Permission is granted to reproduce and modify this paper under the terms of the Creative Commons NonCommercial ShareAlike 2.5 license.

    Full text: http://www.itia.ntua.gr/en/getfile/683/1/documents/2005HESSPlastiras.pdf (404 KB)

    Additional material:

    See also: http://dx.doi.org/10.5194/hess-9-507-2005

    Works that cite this document: View on Google Scholar or ResearchGate

    Other works that reference this work (this list might be obsolete):

    1. Chung, E. S., and K. S. Lee, A social-economic-engineering combined framework for decision making in water resources planning, Hydrology and Earth System Sciences, 13, 675-686, 2009.
    2. Parisopoulos, G. A., M. Malakou, and M. Giamouri, Evaluation of lake level control using objective indicators: The case of Micro Prespa, Journal of Hydrology, 367(1-2), 86-92, 2009.
    3. #Romanescu, G., C. Stoleriu, and A. Lupascu, Morphology of the lake basin and the nature of sediments in the area of Red Lake (Romania), Annals of the University of Oradea – Geography Series, XX(1), 44-57, 2010.
    4. #Sargentis G. F., V. Symeonidis, and N. Symeonidis, Rules and methods for the development of a prototype landscape (Almyro) in north Evia by the creation of a thematic park, Proceedings of the 12th International Conference on Environmental Science and Technology (CEST2011), Rhodes, Greece, 2011.
    5. Shamsudin, S., A. A. Rahman and Z. B. Haron, Water level evaluation at Southern Malaysia reservoir using fuzzy composite programming, International Journal of Engineering and Advanced Technology, 2(4), 127-132, 2013.
    6. #Romanescu, G., C. C. Stoleriu, and A. Enea, Water management, Limnology of the Red Lake, Romania, Springer, 2013.
    7. Zhang, T., W. H. Zeng, S. R. Wang, and Z. K. Ni, Temporal and spatial changes of water quality and management strategies of Dianchi Lake in southwest China, Hydrology and Earth System Sciences, 18, 1493-1502, doi:10.5194/hess-18-1493-2014, 2014.
    8. Zhang, T., W. H. Zeng, and F. L. Yang, Applying a BP neural network approach to the evolution stage classification of China Rift Lakes, International Journal of Modeling and Optimization, 4(6), 450-454, 2014.
    9. Tegos, M., I. Nalbantis, and A. Tegos, Environmental flow assessment through integrated approaches, European Water, 60, 167-173, 2017.

Book chapters and fully evaluated conference publications

  1. G.-F. Sargentis, R. Ioannidis, M. Chiotinis, P. Dimitriadis, and D. Koutsoyiannis, Aesthetical issues with stochastic evaluation, Data Analytics for Cultural Heritage, edited by A. Belhi, A. Bouras, A.K. Al-Ali, and A.H. Sadka, doi:10.1007/978-3-030-66777-1_8, Springer, 2021.

    Throughout human history, the quantification of aesthetics has intrigued philosophers, artists, and mathematicians alike. In this chapter, a methodology based on stochastic mathematics is applied for the quantification of aesthetic attributes of paintings and landscapes. The paintings analyzed include Da Vinci, Pablo Picasso, and various other celebrated paintings from 1250 AD to modern times. In regard to landscapes, the analysis focuses on the aesthetic transformations imposed to landscapes from wind energy projects. The methodology used is called stochastic 2D-C analysis and is based on a stochastic computational tool that analyzes brightness fluctuation in images. The 2D-C tool is used to measure the degree of variability and in particular the change in variability vs. scale. The application of the tool provides (a) input on the qualitative efficiency of mainstream methods used in landscape-impact analysis, (b) insights into the expression forms of the examined artists and historical periods, and finally (c) evidence that can be used in the search of the originality of an artwork of disputed authorship.

  1. G.-F. Sargentis, K. Hadjibiros, and A. Christofides, Plastiras lake: the impact of water level on the aesthetic value of landscape, Proceedings of the 9th International Conference on Environmental Science and Technology (9CEST), Rhodes, B, 817–824, Department of Environmental Studies, University of the Aegean, 2005.

    The Plastiras Lake is an artificial reservoir created in 1959 for hydroelectric production. Following different changes in the social, economic and physical context of the area, the water of the lake has been used mainly for irrigation and drinking water supply. Recently, the beautiful scenery of the lake has been considered attractive by visitors and therefore the area has seen a significant touristic development. However, because of the water release mainly for agricultural, but also for hydroelectric purposes, the surface level of the lake varies significantly in the range between the lowest level of 776 m and the overflow level of 792 m. The result is a considerably negative impact on the landscape. The aesthetic value of the scenery has been assessed by a research team through field visits, landscape visual examination, photographic recording, digital image processing, as well as with a survey among visitors. It has been noticed that the most important impact from the level variation is the development of a dead-zone around the lake shore. This zone has different characteristics in the northern and in the southern part. The analysis of the form and size of the dead-zone may provide a concrete assessment of the aesthetic impact, although a quantified approach remains difficult. Moreover, information from the survey gives a significant, yet subjective, estimation of the aesthetic impact. The inhabitants, the regular and the occasional visitors are partially in agreement that the scenery is significantly more valuable when the water level is around 786 m or higher, as compared to when it is around 782 m or lower. If the conservation of the environment and the touristic development of the area are priority objectives, the management of water release through the establishment of a lower limit for the surface level appears to be mandatory.

    Full text: http://www.itia.ntua.gr/en/getfile/1005/1/documents/srcosmos.pdf (1136 KB)

    Other works that reference this work (this list might be obsolete):

    1. Stamou, A. I., K. Hadjibiros, A. Andreadakis and A. Katsiri, Establishing minimum water level for Plastiras reservoir (Greece) combining water quality modelling with landscape aesthetics, Environmental Modeling and Assessment, 12(3), 157-170, 2007.
    2. #Sargentis G. F., V. Symeonidis, and N. Symeonidis, Rules and methods for the development of a prototype landscape (Almyro) in north Evia by the creation of a thematic park, Proceedings of the 12th International Conference on Environmental Science and Technology (CEST2011), Rhodes, Greece, 2011.

  1. K. Hadjibiros, A. Katsiri, A. Andreadakis, D. Koutsoyiannis, A. Stamou, A. Christofides, A. Efstratiadis, and G.-F. Sargentis, Multi-criteria reservoir water management, Proceedings of the 9th International Conference on Environmental Science and Technology (9CEST), Rhodes, A, 535–543, Department of Environmental Studies, University of the Aegean, 2005.

    The Plastiras dam was constructed in the late 1950s mainly for electric power production, but it has also partially covered irrigation needs and water supply of the plain of Thessaly. Later, the site has been designated as an environment conservation zone because of ecological and landscape values, while tourist activities have been developed around the reservoir. Irrigation of agricultural land, hydroelectric production, drinkable water supply, tourism, lake water quality and scenery conservation have evidently been conflicting targets for many years. Good management would require a multi-criteria decision making. Historical data show that the irregular water release has resulted in a great annual fluctuation of the reservoir water level. This situation could be improved by a rational management of abstractions. Apparently, higher release leads simultaneously to more power production and to irrigation of a larger agricultural land. Moreover, demands for electricity and for irrigation are partially competing to each other, due to different optimal time schedules of releases. On the other hand, higher water release leads to lower water level in the reservoir and, therefore, it decreases the beauty of the scenery and deteriorates the trophic state of the lake. Such degradation affects the tourist potential as well as the quality of drinking water supplied by the reservoir. A multi-criteria approach uses different scenarios for the minimum permissible water level of the reservoir, if a constant annual release is applied. The minimum level concept is a simple and functional tool, because it is easily understood by people, certified and incorporated into regulations. The quantity of water that would be yearly available is a function of the minimum level allowed. The water quality depends upon the trophic state of the lake, mainly the concentration of chlorophyll-a, which determines the state of eutrophication and is estimated by water quality simulation models, taking into account pollutant loads such as nitrogen and phosphorus. The value of the landscape is much depending on the water level of the lake, because for lower levels a dead-zone appears between the surface of the water and the surrounding vegetation. When this dead zone is large, it seems lifeless and the lake appears partially empty. Quantification of this visual effect is not easy, but it is possible to establish a correspondence between the aesthetic assessment of the scenery and the minimum allowed reservoir level. Using results from hydrological analysis, water quality models and landscape evaluation, it seems possible to construct a multi-criterion table with different criteria described against alternatives and with a plot of three relative indices against the minimum level allowed. However, decision making has to take into account the fact that comparison or merging of indices corresponding to different criteria analysis encompasses a degree of arbitrariness. More objective decisions would be possible if different benefits and costs were measured in a common unit. Moreover, management will be sensitive to different social pressures.

    Related works:

    • [17] Posterior more complete version.

    Full text: http://www.itia.ntua.gr/en/getfile/682/1/documents/2005CestRhodesPlastiras.pdf (141 KB)

    Other works that reference this work (this list might be obsolete):

    1. Stamou, A.I., K. Hadjibiros, A. Andreadakis and A. Katsiri, Establishing minimum water level for Plastiras reservoir (Greece) combining water quality modelling with landscape aesthetics, Environmental Modeling and Assessment, 12(3), 157-170, 2007.
    2. #Sargentis G. F., V. Symeonidis, and N. Symeonidis, Rules and methods for the development of a prototype landscape (Almyro) in north Evia by the creation of a thematic park, Proceedings of the 12th International Conference on Environmental Science and Technology (CEST2011), Rhodes, Greece, 2011.

  1. K. Hadjibiros, D. Koutsoyiannis, A. Katsiri, A. Stamou, A. Andreadakis, G.-F. Sargentis, A. Christofides, A. Efstratiadis, and A. Valassopoulos, Management of water quality of the Plastiras reservoir, 4th International Conference on Reservoir Limnology and Water Quality, Ceske Budejovice, Czech Republic, doi:10.13140/RG.2.1.4872.4723, 2002.

    The problems associated with establishing a "safe" minimum level for a reservoir serving multiple and conflicting purposes (hydroelectric power generation, water supply, irrigation and recreation) are discussed. A comprehensive approach of the problem considers three different criteria. The first criterion is water quantity. Available long-term reservoir inflow data are analyzed to establish 'sustainable" water inputs in relation to demands that have to be satisfied. The second criterion is ecology and landscape and considers how fluctuations of the reservoir level affect the lake banks vegetation. It discusses the implications to aesthetic, touristic and beneficial uses. The third criterion is water quality and considers how the fluctuations in lake volume affect the chemical and biological status of the lake. For this purpose a one-dimensional eutrophication model was used. The minimum water level is established from the synthesis of the above, using a multi-criteria analysis.

    Remarks:

    Full text: http://www.itia.ntua.gr/en/getfile/546/1/documents/2002TsehiaPlastiras.pdf (241 KB)

    See also: http://dx.doi.org/10.13140/RG.2.1.4872.4723

    Other works that reference this work (this list might be obsolete):

    1. #Spanoudaki, K., and A. Stamou, The prospects of developing integrated ecological models for the needs of the WFD 2000/60, Proceedings of the International Conference for the Restoration and Protection of the Environment V, Mykonos, 2004.
    2. #Stamou, A. I., K. Nanou-Giannarou, and K. Spanoudaki, Best modeling practices in the application of the Directive 2000/60 in Greece, Proc. 3rd IASME/WSEAS Int. Conf. on Energy, Environment, Ecosystems and Sustainable Development, 388-397, 2007.
    3. Stamou, A.I., K. Hadjibiros, A. Andreadakis, and A. Katsiri, Establishing minimum water level for Plastiras reservoir (Greece) combining water quality modelling with landscape aesthetics, Environmental Modeling and Assessment, 12(3), 157-170, 2007.

Conference publications and presentations with evaluation of abstract

  1. D. Dimitrakopoulou, R. Ioannidis, G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, E. Chardavellas, S. Vavoulogiannis, N. Mamassis, and D. Koutsoyiannis, Social uncertainty in flood risk: field research, citizens’ engagement, institutions' collaboration, IAHS 100th Anniversary – 11th IAHS-AISH Scientific Assembly 2022, Montpellier, France, IAHS2022-351, International Association of Hydrological Sciences, 2022.

    The well-presented results and the high efficiency of new tools in the evaluation of flood risk leads us to forget the fundamental tool for analysis which is field research, citizens’ engagement and institutions collaboration.

    Having in mind that field-research must be connected with modern tools, this paper shows that only engineers are appropriate for flood-study field-research. In addition, a training protocol is necessary. This protocol describes the method of the field-research, the organization of the team, legal distractions in field research, proper software needed for field research, characteristic points of interest, code name and proper depiction of the points. In addition, describes an efficient formula of the reports in order to be used in GIS and evaluated in DEM and risk analysis.

    In addition, the cooperation of research and governmental institutions is crucial for the quantification of risks associated with natural hazards. Research institutions, local-government authorities and environmental agencies are all necessary, in order to combine both theoretical and practical knowledge for the generation of optimized risk-assessment results. Thus, a targeted methodology was formed including a process of successive cycles of communications relevant those agencies and institutions, aiming to utilize both their qualitative and quantitative knowledge and overall, to set a solid data-based foundation for the later stages of the flood-risk analysis.

    Last but not least, in the process of investigating for locations with increased flood risk, citizens’ engagement should be sought. During the research field or through an online form, the citizens should be asked to fill in a relative questionnaire with brief, multiple choice questions, regarding their residence, their years of residence, the frequency of floods that they can recall and their location and other relates topics. The permanent residents' experience can lead to the location of areas prone to flood that cannot be located otherwise, in terms of designs. Consequently, it is argued that the residents must play an active role in the conception, design and implementation of flood protection projects and infrastructure projects, overall.

    Additional material:

    See also: https://meetingorganizer.copernicus.org/IAHS2022/IAHS2022-351.html

  1. G.-F. Sargentis, I. Meletopoulos, T. Iliopoulou, P. Dimitriadis, E. Chardavellas, D. Dimitrakopoulou, A. Siganou, D. Markantonis, K. Moraiti, K. Kouros, M. Nikolinakou, and D. Koutsoyiannis, Modelling water needs; from past to present. Case study: The Municipality of Western Mani, IAHS 100th Anniversary – 11th IAHS-AISH Scientific Assembly 2022, Montpellier, France, IAHS2022-400, International Association of Hydrological Sciences, 2022.

    In traditional and isolated societies human needs were limited and the resources were sufficient. For example, 70 years ago, water needs per capita in Greece were about 7,2 m3/year. But the basic perception of development is the abundance of water resources. For example, tourist development changes the culture of water consumption as modern way of living needs 150 m3/year per capita. In the same time one visitor would prefer accommodation with pools demanding even more fresh water.

    Fortunately, there are many technological solutions to cover this gap of consumption. Unfortunately, some of them are not efficient or sustainable and other have big cost of energy.

    This research examines the case study of the Municipality of Western Mani in South Greece, an area with high touristic development, detects the transformation of needs and potential technical solutions which are evaluated with criteria: needs coverage; sustainability; preservation of the landscape.

    Stochastic models for the simulation of the function of water infrastructures in different scales (from traditional to modern) are applied.

    Full text: http://www.itia.ntua.gr/en/getfile/2214/1/documents/IAHS_Sargentis.pdf (1662 KB)

    Additional material:

    See also: https://meetingorganizer.copernicus.org/IAHS2022/IAHS2022-400.html

  1. P. Dimitriadis, T. Iliopoulou, G.-F. Sargentis, and D. Koutsoyiannis, Spatial and temporal long-range dependence in the scale domain, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-13051, doi:10.5194/egusphere-egu22-13051, European Geosciences Union, 2022.

    Long-range dependence (LRD) estimators are traditionally applied in the lag domain (e.g., through the autocovariance or variogram) or in the frequency domain (e.g., through the power-spectrum), but not as often in the scale domain (e.g., through variance vs. scale). It has been contended that the latter case introduces large estimation bias and thus, corresponds to "bad estimators" of the LRD. However, this reflects a misrepresentation or misuse of the concept of variance vs. scale. Specifically, it is shown that if the LRD estimator of variance vs. scale is properly defined and assessed (see literature studies for the so-called climacogram estimator), then the stochastic analysis of variance in the scale domain can be proven to be a robust means to identify and model any LRD process ranging from small scales (fractal behavior) to large scales (LRD, else known as the Hurst-Kolmogorov dynamics) for any marginal distribution. Here, we show how the above definitions can be applied both in spatial and temporal scales, with various applications in geophysical processes, key hydrological-cycle processes, and related natural hazards.

    Full text: http://www.itia.ntua.gr/en/getfile/2207/1/documents/EGU22-13051_presentation-h884570.pdf (1261 KB)

    Additional material:

  1. D. Markantonis, A. Siganou, K. Moraiti, M. Nikolinakou, G.-F. Sargentis, P. Dimitriadis, M. Chiotinis, T. Iliopoulou, N. Mamassis, and D. Koutsoyiannis, Determining optimal scale of water infrastructure considering economical aspects with stochastic evaluation – Case study at the Municipality of Western Mani, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3039, doi:10.5194/egusphere-egu22-3039, European Geosciences Union, 2022.

    Infrastructures for the supply of water are one of the most necessary facilities in modern life. The optimal design of such infrastructures (for example, dams or even small-size tanks) is often a great challenge in civil engineering, given the large number of factors required for their design (e.g., feasibility, reliability, cost effectiveness, resilience). One of the most critical decisions that may have a great impact on the optimization procedure is the determination of the scale of the proposed system.

    During a study of such a design of a water supply infrastructure in the Municipality of Western Mani, it became clear that several solutions of different scales coexisted. Ultimately, the cost-benefit factors were the most heavily considered ones, provided that the required reliability was met. Stochastic methods have been proven to be appropriate tools for studying such highly complex and uncertain puzzles. The current study intends to approach this problem by considering solutions of different scales, and to establish the long-term cost effectiveness as the main criterion to evaluate the different solutions.

    Full text: http://www.itia.ntua.gr/en/getfile/2206/1/documents/EGU22-3039_presentation-h8044131.pdf (1013 KB)

    Additional material:

  1. K. Moraiti, D. Markantonis, M. Nikolinakou, A. Siganou, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, I. Meletopoulos, N. Mamassis, and D. Koutsoyiannis, Optimizing water infrastructure solutions for small-scale distributed settlements – Case study at the Municipality of Western Mani., EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3055, doi:10.5194/egusphere-egu22-3055, European Geosciences Union, 2022.

    Water infrastructure is an indicator of human civilization and its evolution. The sustainable water management and distribution to local communities remains a critical engineering priority so that the most efficient usage is achieved. In this analysis the design of water-infrastructure establishments is studied for the community of the Municipality of Western Mani (western Peloponnese, Greece).

    One of the main issues that arise is the presence of karstic-limestone geological structure at the study area with no permanent watercourses. Furthermore, the lack of data about the current quantity of surface water makes it difficult to formulate trustworthy conclusions on the availability of water resources. Additionally, the notable growth of the tourist sector during the summer months in the past few years exacerbates this issue. Due to the above reasons, the available water is not enough to cover the needs of the Municipality, especially during the summer.

    After examining all the possible options that have been proposed to increase the water availability (e.g., through dams, wells, desalination, water ponds etc.), we investigate an optimal solution that aims to achieve a more efficient water management and distribution to the communities of Western Mani. To this aim, we apply a multi-criteria decision-making approach by also considering local traditional water harvesting systems to increase water resilience.

    Full text: http://www.itia.ntua.gr/en/getfile/2205/1/documents/EGU22-3055_presentation-h343475.pdf (1374 KB)

    Additional material:

  1. M. Nikolinakou, K. Moraiti, A. Siganou, D. Markantonis, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, I. Meletopoulos, N. Mamassis, and D. Koutsoyiannis, Investigating the water supply potential of traditional rainwater harvesting techniques used – A case study for the Municipality of Western Mani, EGU General Assembly 2022, Vienna, Austria & Online, European Geosciences Union, 2022.

    Water availability is a critical issue for growing local communities. For example, in the Municipality of Western Mani (western Peloponnese, Greece) tourist development has caused scarcity of water intensifying during the summer period. In this context, multiple solutions are being studied in order to assist the local communities of Western Mani to deal with this situation.

    This study focuses on traditional water harvesting structures and more specifically cisterns. In the past, a cistern was present nearby or almost at every house, collecting rain water so as to cover the various needs of the inhabitants, including human consumption and irrigation. However, although cisterns today have fallen into disuse due to the developments of modern water supply systems, they remain an important part of cultural heritage and an architectural element of great interest.

    In this work, we evaluate the potential of traditional water infrastructures to cover domestic needs employing the method of stochastic simulation based on hydrological data and by also taking into account traditional architecture.

    Full text: http://www.itia.ntua.gr/en/getfile/2204/1/documents/EGU22-3063_presentation-h7595401.pdf (2420 KB)

    Additional material:

  1. A. Siganou, M. Nikolinakou, D. Markantonis, K. Moraiti, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, M. Chiotinis, N. Mamassis, and D. Koutsoyiannis, Stochastic simulation of hydrological timeseries for data scarce regions - Case study at the Municipality of Western Mani, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3086, doi:10.5194/egusphere-egu22-3086, European Geosciences Union, 2022.

    West Mani, an attractive place in western Peloponnese, Greece, faces water shortage. The problem lies not only in the quantity but also in the quality of the available water. Investigating the options for the sustainable management of water resources, utilizing surface water seems to be the optimal solution. However, the complex geomorphology and geology of the study area, and its particular its karstic structure, when combined with the scarcity of hydrological data, makes the estimation of surface water availability challenging. As a result, it is considered necessary to take hydrological uncertainty into account using stochastic analysis. To this aim, we generate synthetic rainfall and streamflow timeseries based on available meteorological data from basins near the area of interest. We then appropriately adjust them so that they represent the magnitude and the variability of the rainfall and streamflow of the study area. For the timeseries generation algorithm, we employ a stochastic model following the Hurst-Kolmogorov dynamics by reproducing marginal distribution, seasonality and persistence.

    Full text: http://www.itia.ntua.gr/en/getfile/2203/1/documents/EGU22-3086_presentation-h6539501.pdf (1720 KB)

    Additional material:

  1. I. Arvanitidis, Μ. Diamanta, G.-F. Sargentis, T. Iliopoulou, P. Dimitriadis, and D. Koutsoyiannis, Identifying links between hydroclimatic variability and economical components using stochastic methods, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-5944, doi:10.5194/egusphere-egu22-5944, European Geosciences Union, 2022.

    Since ancient times water has been a substantial factor for driving economic growth, as abundance in water resources can be linked to the development of prosperous communities. This study examines the effect of water resources availability on different sectors of the economy, by identifying components of Gross Domestic Product which are most affected by key water cycle processes and water infrastructures. In this analysis, we investigate the correlation among the above processes, on both temporal and spatial scale with the implementation of stochastic methods, in order to assess the sensitivity of the economy to hydroclimatic variability. We also take into consideration the effect of hydroclimatic extremes such as droughts and the limitations they may impose on growth. Differences between climate zones are taken into consideration by the Köppen climate index.

    Full text: http://www.itia.ntua.gr/en/getfile/2202/1/documents/EGU22-5944_presentation-h5736302.pdf (1494 KB)

    Additional material:

  1. S. Vrettou, A. Trompouki, T. Iliopoulou, G.-F. Sargentis, P. Dimitriadis, and D. Koutsoyiannis, Investigation of stochastic similarities between wind and waves and their impact on offshore structures, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3082, doi:10.5194/egusphere-egu22-3082, European Geosciences Union, 2022.

    Offshore wind farms are increasingly gaining acceptance in the field of energy production. From an engineering point of view, such offshore structures are affected by various sources of uncertainty. The most severe one, is the impact that wave (height and period) and wind processes have, either at the fatigue, and in some cases failure of such structures, or at the efficiency of their energy production. In this work, we are focusing on the stochastic properties of the above processes and on their impacts on offshore structures. By extracting data from gauging stations at the Aegean Sea, we specifically examine the stochastic similarities among the marginal moments and the correlation function with focus on the extremes of the wind velocity and the wave height and period, and we discuss their impacts on open sea structures.

    Full text: http://www.itia.ntua.gr/en/getfile/2201/1/documents/Presentation_O64qHGK.pdf (2641 KB)

    Additional material:

  1. A. Trompouki, S. Vrettou, G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, and D. Koutsoyiannis, Investigation of the spatial correlation structure of 2-D wave fields at the Aegean Sea, EGU General Assembly 2022, Vienna, Austria & Online, EGU22-3083, doi:10.5194/egusphere-egu22-3083, European Geosciences Union, 2022.

    The great potential of oceanic energy resources adds a new challenge in the field of off-shore engineering, that of the efficient energy extraction from sophisticated structures in the open sea. An additional challenge that the engineers have to face is the intrinsic uncertainty of the oceanic processes. In this work, we investigate the uncertainty of the wave process through the estimation of the variability in two-dimensional wave height and direction data. These are retrieved from satellite images over the Aegean Sea for a 5-year period with a 3-hour resolution. Particularly, we estimate first-order moments, considering the double seasonality of the wave events, and also the correlation structure in terms of the climacogram (i.e., variance of the averaged process vs. spatial scale). Finally, we discuss on how the spatial dependence of the wave field is affected by various weather events.

    Full text: http://www.itia.ntua.gr/en/getfile/2200/1/documents/EGU_presentation__Alexandra_Trompouki.pdf (1811 KB)

    Additional material:

  1. E. Manta, R. Ioannidis, G.-F. Sargentis, and A. Efstratiadis, Aesthetic evaluation of wind turbines in stochastic setting: Case study of Tinos island, Greece, European Geosciences Union General Assembly 2020, Geophysical Research Abstracts, Vol. 22, Vienna, EGU2020-5484, doi:10.5194/egusphere-egu2020-5484, 2020.

    Wind turbines are large-scale engineering infrastructures that may cause significant social reactions, due to the anticipated aesthetic nuisance. On the other hand, aesthetics is a highly subjective issue, thus any attempt towards its quantification requires accounting for the uncertainty induced from subjectivity. In this work, taking as example the Aegean island of Tinos, Cyclades, Greece, we present a stochastic-based methodology for evaluating the feasibility of developing wind parks in terms of their aesthetic impacts. At first, a field analysis is been conducted along with photographic surveying, 3D representation and the opinion of the target population regarding the development of wind parks across the island. Subsequently, the landscape transformations that will be caused from the wind turbines are assessed according to the theory of aesthetics, which are depicted by using suitable spatial analysis tools in GIS environment. The 3D representation images along with the maps are finally assessed through stochastic analysis, in order to quantify the visual impacts to the landscape and the nuisance to local community.

    Full text:

    See also: https://meetingorganizer.copernicus.org/EGU2020/EGU2020-5484.html

    Other works that reference this work (this list might be obsolete):

    1. Vlami, V., I. P. Kokkoris, S. Zogaris, G. Kehayias, and P. Dimopoulos, Cultural ecosystem services in the Natura 2000 network: Introducing proxy indicators and conflict risk in Greece, Land, 10(1), 4, doi:10.3390/land10010004, 2021.

  1. E. Frangedaki, and G.-F. Sargentis, Optimizing engineering aspects of earth constructions.The earth as "common" material., European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-11412-1, European Geosciences Union, 2019.

    Earth is one of the most abundant, most locally available, cheapest and lowest impact materials it's possible to build with. Over 70% of landmass is either pure clay or laterite - clay (with some iron content). Earth is a 100% eco-friendly building material, neither it is manufactured nor transported in construction area. There are several empirical methods and many laboratory tests to determine the proportion of raw materials that we can use but the aim of this work is to present it as a common resource, free material for construction. In this work we present the appropriate laboratory tests in order to use the earth of an area for construction. Modern construction thinking and Low-Tech architecture (i.e. low cost construction by non-specialists) have updated techniques so that the earth can become a basic material for the optimization of ecological architecture.This work presents why these techniques is important to be as common heritage accessible by all members of a society especially in crisis periods.

    Remarks:

    This research has been supported by the OptArch project: "Optimization Driven Architectural Design of Structures" (No: 689983) belonging to the Marie Skłodowska-Curie Actions (MSCA) Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2015.

    Full text:

  1. G.-F. Sargentis, E. Frangedaki, P. Dimitriadis, and D. Koutsoyiannis, Development of a web platform of knowledge exchange for optimal selection of building materials based on ecological criteria, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-10395, European Geosciences Union, 2019.

    Decisions on technical issues must simultaneously satisfy several conflicting objectives. Several methods have been developed to help identify the "optimal" decision. Such decisions are made by politicians but experts, constructors and the society must have the ability to overview and influence these decisions. The interaction of the different groups can be implemented using a web platform. The criteria to optimize this platform and its architecture are analysed. The aim is to give to non-expert users a general view of the problem and the solutions suggested, and help them form an informed opinion on a technical problem. At the same time it would help politicians and experts to take into account the public opinions in decision making.

    Remarks:

    This research has been supported by the OptArch project: "Optimization Driven Architectural Design of Structures" (No: 689983) belonging to the Marie Skłodowska-Curie Actions (MSCA) Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2015.

    Full text:

  1. Μ. Sako, E. Tsoli, R. Ioannidis, E. Frangedaki, G.-F. Sargentis, and D. Koutsoyiannis, Optimizing the size of Hilarion dam with technical, economical and environmental parameters, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-15297, European Geosciences Union, 2019.

    The construction and operation of large dams has been questioned in recent years as, despite their positive effect on the economy, they are regarded as negative to the environment. The size of a dam, in particular, is an important aspect of this debate as it is thought to increase its economic benefit but also its environmental impacts. We investigate the dam scale issue based on a case study for the Hilarion dam, located in Kozani, Greece. More specifically, in an effort to examine the problem of optimal project scale, we quantify selected technical, economic and environmental parameters of the Hilarion dam for different hypothetical scenarios of dam size including its original size. The various scenarios are compared on a cost-benefit basis to provide a first approximation of the exact relation between dam size and its technical, environmental and economic characteristics.

    Remarks:

    This research has been supported by the OptArch project: "Optimization Driven Architectural Design of Structures" (No: 689983) belonging to the Marie Skłodowska-Curie Actions (MSCA) Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2015.

    Full text:

  1. R. Ioannidis, P. Dimitriadis, G.-F. Sargentis, E. Frangedaki, T. Iliopoulou, and D. Koutsoyiannis, Stochastic similarities between hydrometeorogical and art processes for optimizing architecture and landscape aesthetic parameters, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-11403, European Geosciences Union, 2019.

    Stochastics help develop a unified perception for natural phenomena and expel dichotomies like random vs. deterministic, as both randomness and predictability coexist and are intrinsic to natural systems which can be deterministic and random at the same time, depending on the prediction horizon and the time scale. The high complexity and uncertainty of natural processes has been long identified through observations as well as extended analyses of hydrometeorological processes such as temperature, humidity, surface wind, precipitation, atmospheric pressure, river discharges etc. All these processes seem to exhibit high unpredictability due to the clustering of events. Art is a mix of determinism (e.g., certain rules have to be followed) and stochasticity (e.g., creativity and inspiration). However, in this analysis we analyse each artistic work in a stochastic approach, and attempt to identify their degree of intrinsic uncertainty. The stochastic analysis includes the investigation of possible Hurst-Kolmogorov behaviour in the art of different periods (visual arts, music, poetry) and of relationships with natural processes. Based on the stochastic analysis of different artworks, we make an image analysis of architectural elements in the landscape in order to formulate an indicator that can be used in engineering.

    Remarks:

    This research has been supported by the OptArch project: "Optimization Driven Architectural Design of Structures" (No: 689983) belonging to the Marie Skłodowska-Curie Actions (MSCA) Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2015.

    Full text:

  1. G.-F. Sargentis, R. Ioannidis, G. Karakatsanis, and D. Koutsoyiannis, The scale of infrastructures as a social decision. Case study: dams in Greece, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-17082, European Geosciences Union, 2018.

    Organized societies require specific infrastructures, among which hydraulic projects are most important. Thus, for the functioning of a society, the water supply and drainage are prerequisites, while a new modern society also needs renewable energy in addition to, and in connection with, high quality water. Dams are key infrastructures in this process. Modern economic and social conditions do not define the limits of what we call "development". In this research we are mapping the limits of the development based on the capacity of the landscape, the water resources, the finances, the political aspects and the criteria of a city’s development.

    Full text:

  1. G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, and D. Koutsoyiannis, Stochastic investigation of the Hurst-Kolmogorov behaviour in arts, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-17740-1, European Geosciences Union, 2018.

    The Hurst-Kolmogorov (HK) behaviour (i.e. power-law decrease of the process variance vs. scale of averaging) has been already identified in numerous geophysical processes highlighting the large uncertainty of Nature in all time scales. In this study, we investigate through the climacogram whether or not some art works (such as paintings, music pieces and poems) also exhibit this behaviour and try to interpret the results in terms of (un)predictability in works of art.

    Full text:

  1. A. Efstratiadis, D. Koutsoyiannis, K. Hadjibiros, A. Andreadakis, A. Stamou, A. Katsiri, G.-F. Sargentis, and A. Christofides, A multicriteria approach for the sustainable management of the Plastiras reservoir, Greece, EGS-AGU-EUG Joint Assembly, Geophysical Research Abstracts, Vol. 5, Nice, doi:10.13140/RG.2.2.23631.48801, European Geophysical Society, 2003.

    The Plastiras reservoir, sited in Western Thessaly, Greece, is a multipurpose project used for irrigation, water supply, hydropower, and recreation; the importance of the latter is continuously increasing as the reservoir landscape becomes attractive to tourists. These uses are competitive and result in a particularly complex problem of water management. Recently, a multidisciplinary analysis was attempted, aiming at determining a rational and sustainable management policy for the Plastiras Lake. This consists of establishing a minimum allowable water level for abstractions, in addition to a proper release policy. Until now, the reservoir level has had a 16 m fluctuation range, affecting negatively both the landscape, due to the exposure of the dead (no-vegetation) zone and the water quality. Three types of analyses were employed, to determine the variation of the corresponding criteria as a function of the allowable minimum level. The first one was the annual safe yield for various reliability levels, derived through a stochastic simulation model for the reservoir operation. The second criterion was the average summer concentration of chlorophyll-a (as indicator of the eutrophic regime of the lake), estimated through a one-dimensional eutrophication model. The final criterion was the aesthetics of the landscape; the relative study was focused on the effects of level variation and determined five fluctuation zones to characterise the quality of the landscape. After multiobjective analysis, and in cooperation with the local authorities and the public, a specific value of the minimum allowable level and a release policy were selected, which are currently on the way to be formally legislated.

    Full text:

    See also: http://dx.doi.org/10.13140/RG.2.2.23631.48801

    Other works that reference this work (this list might be obsolete):

    1. Gounaridis, D., and G. N. Zaimes, GIS-based multicriteria decision analysis applied for environmental issues: the Greek experience, International Journal of Applied Environmental Sciences, 7(3), 307–321, 2012.

  1. S. Sigourou, V. Pagana, P. Dimitriadis, A. Tsouni, T. Iliopoulou, G.-F. Sargentis, R. Ioannidis, E. Chardavellas, D. Dimitrakopoulou, N. Mamassis, C. Contoes, and D. Koutsoyiannis, Flood risk assessment in the region of Attica, 9th International Conference on Civil Protection & New Technologies - Safe Thessaloniki 2022, Thessaloniki, Greece, September 2022.

    Full text: http://www.itia.ntua.gr/en/getfile/2238/1/documents/2022-09-29-FLOOD_RISK_ASSESSMENT_IN_THE_REGION_OF_ATTICA-presentation.pdf (8756 KB)

  1. S. Sigourou, V. Pagana, P. Dimitriadis, A. Tsouni, T. Iliopoulou, G.-F. Sargentis, R. Ioannidis, E. Chardavellas, D. Dimitrakopoulou, N. Mamassis, C. Contoes, and D. Koutsoyiannis, Proposed methodology for urban flood-risk assessment at river-basin level: the case study of the Pikrodafni river basin in Athens, Greece, Global Flood Partnership 2022 Annual Meeting, Leeds, UK, September 2022.

    The need for and the complexity of flood protection works require the development of advanced methodologies for flood risk assessment, especially considering that land cover changes, climate change and human interventions in the riverbed may severely affect the river flow. In the present study, a new methodology for urban flood risk assessment is introduced and implemented at the Pikrodafni river basin (Athens, Greece), by analyzing the vulnerability and the exposure of the river basin of Pikrodafni’s river to flood risk, in conjunction with the actual physical and socioeconomic parameters in order to propose mitigation measures. In March 2021, a Programming Agreement was signed between the Prefecture of Attica and the NOA – Part A – to conduct the study entitled ARIA «Earthquake, Fire and Flood risk assessment in the region of Attica» funded by the Prefecture of Attica. It’s the first time that such a holistic approach for flood risk assessment is implemented on building-block scale in Greece. The prototype knowledge created through the project supports the Prefecture of Attica in the optimum implementation of the National Civil Protection Plan. This serves the operational needs during crisis, as well as the preparedness and the strategic decision making towards disaster resilience. All the above-mentioned factors were also confirmed and positively evaluated according to the stakeholders’ feedback.

    Full text: http://www.itia.ntua.gr/en/getfile/2237/1/documents/FINposter_Proposed_methodology_for_urban_flood-risk_assessment.pdf (5618 KB)

Presentations and publications in workshops

  1. A. Tsouni, S. Sigourou, V. Pagana, D. Koutsoyiannis, N. Mamassis, A. Koukouvinos, P. Dimitriadis, T. Iliopoulou, G.-F. Sargentis, R. Ioannidis, D. Dimitrakopoulou, E. Chardavellas, S. Vavoulogiannis, and V. Kyriakouli, Flood risk assessment in the Pikrodafni basin, Presentation of results for the 1st Phase of the Program Agreement between Attica Regional Authority and NOA, Athens, National Observatory of Athens, 2022.

    Full text: http://www.itia.ntua.gr/en/getfile/2190/1/documents/20220516.pdf (13374 KB)

Various publications

  1. G.-F. Sargentis, and N. Mamassis, [No English title available], 75–80, 2021.

    Full text: http://www.itia.ntua.gr/en/getfile/2131/1/documents/2021_ktirio_small_water.pdf (1076 KB)

Educational notes

  1. D. Koutsoyiannis, M. Pantazidou, N. Mamassis, G.-F. Sargentis, P. Thanopoulos, S. Lampropoulos, D Vamvatsikos, and K. Hadjibiros, Lecture Notes for the Laboratory on Humanities, School of Civil Engineering – National Technical University of Athens, Athens, 2020.

    Full text:

    Additional material:

  1. G.-F. Sargentis, Lecture notes on Environmental Impacts: The aesthetic element at dams, 28 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, October 2019.

    Full text: http://www.itia.ntua.gr/en/getfile/1995/1/documents/perivalon_aesthetics.pdf (3564 KB)

  1. A. Efstratiadis, G.-F. Sargentis, and N. Mamassis, Lecture notes on Environmental Impacts: Analysis of environmental impacts from large hydraulic structures, 37 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, October 2019.

    Full text: http://www.itia.ntua.gr/en/getfile/1993/1/documents/EnvImpacts2019_HydroWorks.pdf (2930 KB)

  1. A. Christofides, A. Efstratiadis, and G.-F. Sargentis, Presentation of the research project "Investigation of scenarios for the management and protection of the quality of the Plastiras Lake", 79 pages, 1 April 2003.

    Remarks:

    Slides from presentation in the postgraduate course "Environmental impacts of hydraulic works".

    Full text:

Academic works

  1. G.-F. Sargentis, Issues of Prosperity: Stochastic evaluation of data related to environment, infrastructures, economy and society, PhD thesis, Department of Water Resources and Environmental Engineering – National Technical University of Athens, June 2022.

    Full text: http://www.itia.ntua.gr/en/getfile/2259/1/documents/phd.pdf (13621 KB)

  1. G.-F. Sargentis, The esthetic element in water, hydraulic works and dams, Diploma thesis, Department of Water Resources, Hydraulic and Maritime Engineering – National Technical University of Athens, Athens, 1998.

    Full text: http://www.itia.ntua.gr/en/getfile/431/1/documents/1998sargentis.pdf (33830 KB)

Research reports

  1. K. Hadjibiros, D. Koutsoyiannis, A. Andreadakis, A. Katsiri, A. Stamou, A. Valassopoulos, A. Efstratiadis, I. Katsiris, M. Kapetanaki, A. Koukouvinos, N. Mamassis, K. Noutsopoulos, G.-F. Sargentis, and A. Christofides, Overview report, Investigation of scenarios for the management and protection of the quality of the Plastiras Lake, Report 1, 23 pages, Department of Water Resources, Hydraulic and Maritime Engineering – National Technical University of Athens, Athens, March 2002.

    The Plastiras Lake is a reservoir used for irrigation, water supply, hydropower, and tourism. These uses are competitive and result in an especially complex problem of water management. In this report the problem is presented and the main points of the three parts of the project are summarised; these three parts are the hydrological study, the quality study, and the landscape study. The conflicting demands are arranged, and water release scenarios are suggested.

    Related project: Investigation of scenarios for the management and protection of the quality of the Plastiras Lake

    Full text:

    Other works that reference this work (this list might be obsolete):

    1. Andreadakis, A., K. Noutsopoulos, and E. Gavalaki, Assessment of the water quality of Lake Plastira through mathematical modelling for alternative management scenarios, Global Nest: the International Journal, 5(2), pp 99-105, 2003.
    2. #Karalis, S. and A . Chioni, 1-D Hydrodynamic modeling of Greek lakes and reservoirs, Ch. 59 in Environmental Hydraulics, Proceedings of the 6th International Symposium on Environmental Hydraulics (ed. by A. I . Stamou), Athens, Greece, 397–401, 2010.
    3. Kalavrouziotis, I. K., A. Τ. Filintas, P. H. Koukoulakis, and J. N. Hatzopoulos, Application of multicriteria analysis in the management and planning of treated municipal wastewater and sludge reuse in agriculture and land development: the case of Sparti’s wastewater treatment plant, Greece, Fresenius Environmental Bulletin, 20(2), 287-295, 2011.

  1. G.-F. Sargentis, and A. Christofides, The landscape, Investigation of scenarios for the management and protection of the quality of the Plastiras Lake, Report 4, 73 pages, Department of Water Resources, Hydraulic and Maritime Engineering – National Technical University of Athens, Athens, March 2002.

    The level of Lake Plastira varies widely due to water release. Specifically, the level varies from 792 m, which is spill level, to 776 m, which is the lowest level. This variation affects the landscape to a high degree. In this report the aesthetics of the landscape of Lake Plastira is examined, focusing on the effects of level variation. The conclusion is that for levels around 786 m or greater, there are minimal effects on the landscape and virtually everyone finds it wonderful. For lower levels, down to about 782 m, the landscape is significantly affected, mostly due to the dead zone revealed by the lowering of the level; most first or second-time visitors find it beautiful, but many inhabitants of the area and people who visit it regularly anticipate problems. For even lower levels, only visitors who do not come regularly may find the landscape satisfactory, and only in a few observation points. Apart from level variation, other problems of the landscape are discussed, namely those resulting from development. Such problems concern roads, boats, buildings, signs, and light pollution, and it is concluded that the area must be protected. In addition, some preliminary suggestions are made concerning the creation of tourist attractions and infrastructure which should fit the character of the area.

    Related project: Investigation of scenarios for the management and protection of the quality of the Plastiras Lake

    Full text: