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The fundamental concepts in the field of water-energy systems and their historical evolution with emphasis on recent developments are reviewed. Initially, a brief history of the relation of water and energy is presented, and the concept of the water-energy nexus in the 21th century is introduced. The investigation of the relationship between water and energy shows that this relationship comprises both conflicting and synergistic elements. Hydropower is identified as the major industry of the sector and its role in addressing modern energy challenges by means of integrated water-energy management is highlighted. Thus, the modelling steps of designing and operating a hydropower system are reviewed, followed by an analysis of theory and physics behind energy hydraulics. The key concept of uncertainty, which characterises all types of renewable energy, is also presented in the context of the design and management of water-energy systems. Subsequently, environmental considerations and impacts of using water for energy generation are discussed, followed by a summary of the developments in the emerging field of maritime energy. Finally, present challenges and possible future directions are presented.
Nikos Mamassis; Andreas Efstratiadis; Panayiotis Dimitriadis; Theano Iliopoulou; Romanos Ioannidis; Demetris Koutsoyiannis. Water and Energy. Handbook of Water Resources Management: Discourses, Concepts and Examples 2021, 619 -657.
AMA StyleNikos Mamassis, Andreas Efstratiadis, Panayiotis Dimitriadis, Theano Iliopoulou, Romanos Ioannidis, Demetris Koutsoyiannis. Water and Energy. Handbook of Water Resources Management: Discourses, Concepts and Examples. 2021; ():619-657.
Chicago/Turabian StyleNikos Mamassis; Andreas Efstratiadis; Panayiotis Dimitriadis; Theano Iliopoulou; Romanos Ioannidis; Demetris Koutsoyiannis. 2021. "Water and Energy." Handbook of Water Resources Management: Discourses, Concepts and Examples , no. : 619-657.
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.
G.-Fivos Sargentis; Theano Iliopoulou; Panayiotis Dimitriadis; Nikolaos Mamassis; Demetris Koutsoyiannis. Stratification: An Entropic View of Society’s Structure. World 2021, 2, 153 -174.
AMA StyleG.-Fivos Sargentis, Theano Iliopoulou, Panayiotis Dimitriadis, Nikolaos Mamassis, Demetris Koutsoyiannis. Stratification: An Entropic View of Society’s Structure. World. 2021; 2 (2):153-174.
Chicago/Turabian StyleG.-Fivos Sargentis; Theano Iliopoulou; Panayiotis Dimitriadis; Nikolaos Mamassis; Demetris Koutsoyiannis. 2021. "Stratification: An Entropic View of Society’s Structure." World 2, no. 2: 153-174.
We conduct a large-scale benchmark experiment aiming to advance the use of machine-learning quantile regression algorithms for probabilistic hydrological post-processing “at scale” within operational contexts. The experiment is set up using 34-year-long daily time series of precipitation, temperature, evapotranspiration and streamflow for 511 catchments over the contiguous United States. Point hydrological predictions are obtained using the Génie Rural à 4 paramètres Journalier (GR4J) hydrological model and exploited as predictor variables within quantile regression settings. Six machine-learning quantile regression algorithms and their equal-weight combiner are applied to predict conditional quantiles of the hydrological model errors. The individual algorithms are quantile regression, generalized random forests for quantile regression, generalized random forests for quantile regression emulating quantile regression forests, gradient boosting machine, model-based boosting with linear models as base learners and quantile regression neural networks. The conditional quantiles of the hydrological model errors are transformed to conditional quantiles of daily streamflow, which are finally assessed using proper performance scores and benchmarking. The assessment concerns various levels of predictive quantiles and central prediction intervals, while it is made both independently of the flow magnitude and conditional upon this magnitude. Key aspects of the developed methodological framework are highlighted, and practical recommendations are formulated. In technical hydro-meteorological applications, the algorithms should be applied preferably in a way that maximizes the benefits and reduces the risks from their use. This can be achieved by (i) combining algorithms (e.g., by averaging their predictions) and (ii) integrating algorithms within systematic frameworks (i.e., by using the algorithms according to their identified skills), as our large-scale results point out.
Georgia Papacharalampous; Hristos Tyralis; Andreas Langousis; Amithirigala W. Jayawardena; Bellie Sivakumar; Nikos Mamassis; Alberto Montanari; Demetris Koutsoyiannis. Probabilistic Hydrological Post-Processing at Scale: Why and How to Apply Machine-Learning Quantile Regression Algorithms. Water 2019, 11, 2126 .
AMA StyleGeorgia Papacharalampous, Hristos Tyralis, Andreas Langousis, Amithirigala W. Jayawardena, Bellie Sivakumar, Nikos Mamassis, Alberto Montanari, Demetris Koutsoyiannis. Probabilistic Hydrological Post-Processing at Scale: Why and How to Apply Machine-Learning Quantile Regression Algorithms. Water. 2019; 11 (10):2126.
Chicago/Turabian StyleGeorgia Papacharalampous; Hristos Tyralis; Andreas Langousis; Amithirigala W. Jayawardena; Bellie Sivakumar; Nikos Mamassis; Alberto Montanari; Demetris Koutsoyiannis. 2019. "Probabilistic Hydrological Post-Processing at Scale: Why and How to Apply Machine-Learning Quantile Regression Algorithms." Water 11, no. 10: 2126.
Since the beginning of the 21st century, the scientific community has made huge leaps to exploit renewable energy sources, with solar radiation being one of the most important. However, the variability of solar radiation has a significant impact on solar energy conversion systems, such as in photovoltaic systems, characterized by a fast and non-linear response to incident solar radiation. The performance prediction of these systems is typically based on hourly or daily data because those are usually available at these time scales. The aim of this work is to investigate the stochastic nature and time evolution of the solar radiation process for daily and hourly scale, with the ultimate goal of creating a new cyclostationary stochastic model capable of reproducing the dependence structure and the marginal distribution of hourly solar radiation via the clearness index KT.
Giannis Koudouris; Panayiotis Dimitriadis; Theano Iliopoulou; Nikos Mamassis; Demetris Koutsoyiannis. A stochastic model for the hourly solar radiation process for application in renewable resources management. Advances in Geosciences 2018, 45, 139 -145.
AMA StyleGiannis Koudouris, Panayiotis Dimitriadis, Theano Iliopoulou, Nikos Mamassis, Demetris Koutsoyiannis. A stochastic model for the hourly solar radiation process for application in renewable resources management. Advances in Geosciences. 2018; 45 ():139-145.
Chicago/Turabian StyleGiannis Koudouris; Panayiotis Dimitriadis; Theano Iliopoulou; Nikos Mamassis; Demetris Koutsoyiannis. 2018. "A stochastic model for the hourly solar radiation process for application in renewable resources management." Advances in Geosciences 45, no. : 139-145.
Water has played a vital role in life in Greece during its long history. Ancient Greek societies were very active in the field of water management, resulting in an impressive variety of hydraulic works. The main purpose of this paper is to discuss the operation of one of the most ancient and extended hydraulic works, the drainage project of Lake Copais in Central Greece. The project was developed and operated by the Minyans, a powerful Mycenaean group. The Minyans partially diverted two large rivers which fed the lake. The water was conveyed towards labyrinthine natural sinkholes, which were formed in limestone terrain. Through the sinkholes, water slowly discharged to the sea. This impressive ancient water management system has gained the attention of many scientists and has been extensively studied by archaeologists and engineers. Still, important questions remain about the way the hydro-system worked. Trying to provide some reliable answers, we have studied the Minyans’ interventions from a hydraulic engineering perspective. Available archeological, hydrological and geological data of the area were used to evaluate the operation of the system. The main elements of the hydro-system are presented and their purposes examined. For this, (i) a water balance model was developed and (ii) the hydro-system was simulated using synthetic time series of the hydrological processes. Several operational cases were examined in order to define critical parameters of the system, such as water level variation and water accumulation in the sinkholes. The analysis reveals some significant factors, which could be related to archaeological findings and the hydro-system’s performance.
N. Mamassis; Sotirios Moustakas; N. Zarkadoulas. The operation of ancient reclamation works at Lake Copais in Greece. Water History 2015, 7, 271 -287.
AMA StyleN. Mamassis, Sotirios Moustakas, N. Zarkadoulas. The operation of ancient reclamation works at Lake Copais in Greece. Water History. 2015; 7 (3):271-287.
Chicago/Turabian StyleN. Mamassis; Sotirios Moustakas; N. Zarkadoulas. 2015. "The operation of ancient reclamation works at Lake Copais in Greece." Water History 7, no. 3: 271-287.
Beyond doubt, desalination is growing rapidly worldwide. However, there are still obstacles to its wider implementation and acceptance such as: (a) high costs and energy use for fresh water production; (b) environmental impacts from concentrate disposal; (c) a complex, convoluted and time-consuming project permitting process; and (d) limited public understanding of the role, importance, benefits and environmental challenges of desalination. In this paper, a short review of desalination in Greece is being made. Data on the cost of desalination shows a decrease in the future and the potential of water desalination in Greece. The paper summarizes the current status in southeastern Greece (e.g., Aegean islands and Crete), and investigates the possibility of production of desalinated water from brackish water.
Konstantinos Zotalis; Emmanuel G. Dialynas; Nikolaos Mamassis; Andreas N. Angelakis. Desalination Technologies: Hellenic Experience. Water 2014, 6, 1134 -1150.
AMA StyleKonstantinos Zotalis, Emmanuel G. Dialynas, Nikolaos Mamassis, Andreas N. Angelakis. Desalination Technologies: Hellenic Experience. Water. 2014; 6 (5):1134-1150.
Chicago/Turabian StyleKonstantinos Zotalis; Emmanuel G. Dialynas; Nikolaos Mamassis; Andreas N. Angelakis. 2014. "Desalination Technologies: Hellenic Experience." Water 6, no. 5: 1134-1150.
Evolution of Water Supply Through the Millennia presents the major achievements in the scientific fields of water supply technologies and management throughout the millennia. It provides valuable insights into ancient water supply technologies with their apparent characteristics of durability, adaptability to the environment, and sustainability. A comparison of the water technological developments in several civilizations is undertaken. These technologies are the underpinning of modern achievements in water engineering and management practices. It is the best proof that "the past is the key for the future." Rapid technological progress in the twentieth century created a disregard for past water technologies that were considered to be far behind the present ones. There are a great deal of unresolved problems related to the management principles, such as the decentralization of the processes, the durability of the water projects, the cost effectiveness, and sustainability issues such as protection from floods and droughts. In the developing world, such problems were intensified to an unprecedented degree. Moreover, new problems have arisen such as the contamination of surface and groundwater. Naturally, intensification of unresolved problems led societies to revisit the past and to reinvestigate the successful past achievements. To their surprise, those who attempted this retrospect, based on archaeological, historical, and technical evidence were impressed by two things: the similarity of principles with present ones and the advanced level of water engineering and management practices. ISBN: 9781843395409 (Print) ISBN: 9781780401041 (eBook)
Andreas N Angelakis; Larry W Mays; Demetris Koutsoyiannis; Nikos Mamassis. Evolution of Water Supply Through the Millennia. Water Intelligence Online 2012, 11, 1 .
AMA StyleAndreas N Angelakis, Larry W Mays, Demetris Koutsoyiannis, Nikos Mamassis. Evolution of Water Supply Through the Millennia. Water Intelligence Online. 2012; 11 ():1.
Chicago/Turabian StyleAndreas N Angelakis; Larry W Mays; Demetris Koutsoyiannis; Nikos Mamassis. 2012. "Evolution of Water Supply Through the Millennia." Water Intelligence Online 11, no. : 1.
Citation Mamassis, N., Efstratiadis, A. and Apostolidou, I.-G., 2012. Topography-adjusted solar radiation indices and their importance in hydrology. Hydrological Sciences Journal, 57 (4), 756–775.
Nikos Mamassis; Andreas Efstratiadis; Ilektra-Georgia Apostolidou. Topography-adjusted solar radiation indices and their importance in hydrology. Hydrological Sciences Journal 2012, 57, 756 -775.
AMA StyleNikos Mamassis, Andreas Efstratiadis, Ilektra-Georgia Apostolidou. Topography-adjusted solar radiation indices and their importance in hydrology. Hydrological Sciences Journal. 2012; 57 (4):756-775.
Chicago/Turabian StyleNikos Mamassis; Andreas Efstratiadis; Ilektra-Georgia Apostolidou. 2012. "Topography-adjusted solar radiation indices and their importance in hydrology." Hydrological Sciences Journal 57, no. 4: 756-775.
Remote sensing can assist in improving the estimation of the geographical distribution of evapotranspiration, and consequently water demand in large cultivated areas for irrigation purposes and sustainable water resources management. In the direction of these objectives, the daily actual evapotranspiration was calculated in this study during the summer season of 2001 over the Thessaly plain in Greece, a wide irrigated area of great agricultural importance. Three different methods were adapted and applied: the remotesensing methods by Granger (2000) and Carlson and Buffum (1989) that use satellite data in conjunction with ground meteorological measurements and an adapted FAO (Food and Agriculture Organisation) Penman-Monteith method (Allen at al. 1998), which was selected to be the reference method. The satellite data were used in conjunction with ground data collected on the three closest meteorological stations. All three methods, exploit visible channels 1 and 2 and infrared channels 4 and 5 of NOAA-AVHRR (National Oceanic and Atmospheric Administration - Advanced Very High Resolution Radiometer) sensor images to calculate albedo and NDVI (Normalised Difference Vegetation Index), as well as surface temperatures. The FAO Penman-Monteith and the Granger method have used exclusively NOAA-15 satellite images to obtain mean surface temperatures. For the Carlson-Buffum method a combination of NOAA-14 and ΝΟΑΑ-15 satellite images was used, since the average rate of surface temperature rise during the morning was required. The resulting estimations show that both the Carlson-Buffum and Granger methods follow in general the variations of the reference FAO Penman-Monteith method. Both methods have potential for estimating the spatial distribution of evapotranspiration, whereby the degree of the relative agreement with the reference FAO Penman-Monteith method depends on the crop growth stage. In particular, the Carlson- Buffum method performed better during the first half of the crop development stage, while the Granger method performed better during the remaining of the development stage and the entire maturing stage. The parameter that influences the estimations significantly is the wind speed whose high values result in high underestimates of evapotranspiration. Thus, it should be studied further in future.
Alexia Tsouni; Charalabos Kontoes; Demetris Koutsoyiannis; Panagiotis Elias; Nikos Mamassis. Estimation of Actual Evapotranspiration by Remote Sensing: Application in Thessaly Plain, Greece. Sensors 2008, 8, 3586 -3600.
AMA StyleAlexia Tsouni, Charalabos Kontoes, Demetris Koutsoyiannis, Panagiotis Elias, Nikos Mamassis. Estimation of Actual Evapotranspiration by Remote Sensing: Application in Thessaly Plain, Greece. Sensors. 2008; 8 (6):3586-3600.
Chicago/Turabian StyleAlexia Tsouni; Charalabos Kontoes; Demetris Koutsoyiannis; Panagiotis Elias; Nikos Mamassis. 2008. "Estimation of Actual Evapotranspiration by Remote Sensing: Application in Thessaly Plain, Greece." Sensors 8, no. 6: 3586-3600.
The influence of the prevailing weather situation on the temporal evolution and geographical distribution of intense rainfall is studied, as a potential tool to improve rainfall prediction. A classification scheme of the atmospheric circulation over the east Mediterranean territory is used for the analysis. The study area is the Sterea Hellas region (central Greece) with an area of about 25,000 km(2). Daily data from 71 rain gages and hourly data from three rain recorders over a 20 year period are used. From these data sets, the intense rainfall events were extracted and analyzed. Several empirical and statistical methods (also including the available tools of a Geographical Information System) are used for the analysis and comparison of rainfall distribution both in time and in space. The analysis shows that the contribution of the concept of weather types to the quantitative point rainfall prediction in short timescale is small, and only the estimation of the probability of occurrence of an intense event is feasible. On the contrary, the relation between the spatial distribution of rainfall and the atmospheric circulation patterns is significant and may be used for improving the forecasting of the geographical distribution of rainfall
Nikos Mamassis; Demetris Koutsoyiannis. Influence of atmospheric circulation types on space-time distribution of intense rainfall. Journal of Geophysical Research 1996, 101, 26267 -26276.
AMA StyleNikos Mamassis, Demetris Koutsoyiannis. Influence of atmospheric circulation types on space-time distribution of intense rainfall. Journal of Geophysical Research. 1996; 101 (D21):26267-26276.
Chicago/Turabian StyleNikos Mamassis; Demetris Koutsoyiannis. 1996. "Influence of atmospheric circulation types on space-time distribution of intense rainfall." Journal of Geophysical Research 101, no. D21: 26267-26276.