Papers by Rodolfo Soncini Sessa
IFAC Proceedings Volumes, 2009
ABSTRACT
CISM International Centre for Mechanical Sciences, 1991
We review an application oriented study on the real time management of Lake Como, a natural multi... more We review an application oriented study on the real time management of Lake Como, a natural multipurpose reservoir in Northern Italy. Emphasis is on the DSS that resulted from the study and has been used by the manager for several years to take his daily decision on the amount of water to be released from the lake. The structure of the DSS, based on the solutions of complex multiobjective deterministic and stochastic optimal control problems, is presented and the performance of the DSS during the first years of use is analyzed.
Topics on System Analysis and Integrated Water Resources Management, 2007
... The IWRM paradigm was selected as the conceptual basis for the development of the PIP procedu... more ... The IWRM paradigm was selected as the conceptual basis for the development of the PIP procedure, but the procedure complies also the rules of the DPSIR scheme adopted by the European Environment Agency (EEA, 1999, see also OECD, 1994 and UNCSD, 1996). ...
Hydrology and Earth System Sciences, 2012
In many developing countries water is a key renewable resource to complement carbon-emitting ener... more In many developing countries water is a key renewable resource to complement carbon-emitting energy production and support food security in the face of demand pressure from fast-growing industrial production and urbanization. To cope with undergoing changes, water resources development and management have to be reconsidered by enlarging their scope across sectors and adopting effective tools to analyze current and projected infrastructure potential and operation strategies. In this paper we use multi-objective deterministic and stochastic optimization to assess the current reservoir operation and planned capacity expansion in the Red River Basin (Northern Vietnam), and to evaluate the potential improvement by the adoption of a more sophisticated information system. To reach this goal we analyze the historical operation of the major controllable infrastructure in the basin, the HoaBinh reservoir on the Da River, explore reoperation options corresponding to different tradeoffs among the three main objectives (hydropower production, flood control and water supply), using multi-objective optimization techniques, namely Multi-Objective Genetic Algorithm. Finally, we assess the structural system potential and the need for capacity expansion by application of Deterministic Dynamic Programming. Results show that the current operation can only be relatively improved by advanced optimization techniques, while investment should be put into enlarging the system storage capacity and exploiting additional information to inform the operation.
Developments in Integrated Environmental Assessment, 2007
Publisher Summary After formulating the Design Problem for the case in which the desired policy i... more Publisher Summary After formulating the Design Problem for the case in which the desired policy is point-valued (PV), this chapter explains the case in which the policy is set-valued (SV). When a PV policy is adopted, there is no uncertainty about the control that is adopted: if the state is x t , the control is m t (x t ).When the policy is set-valued, however, if the state is x t the control can be any of those in the set M t (x t ): it will be up to the regulator to decide at time (t) which one to implement. One has to take account of this uncertainty when defining the Design Problem. For this reason, it is advisable not to describe the system with a mechanistic or empirical model, but with a Markov chain instead. The first section of this chapter takes up the subject again; to then use the notions that have been given in this chapter with the aim of formalizing the SV Design Problem.
The Environmental Impact Assessment (EIA) is a procedure widely used in public decision-making fo... more The Environmental Impact Assessment (EIA) is a procedure widely used in public decision-making for transportation infrastructures and services. It aims at supporting decisions through the identification and evaluation of the impacts of the proposed projects on society, environment, land use, and economy. Unfortunately, in practice, at the time when the formal EIA procedure starts the type, scale, and, location of the projects have often already been decided based on a restricted set of economic, technical, or political criteria. A better decision-making process should consider several feasible alternatives identified and evaluated with the participation of the stakeholders and the public. The paper presents a case study of an environmental impact assessment for the choice of the transportation system in a tourist village on the Italian Alps with problems of traffic congestion. Alternative multimodal transportation systems, including demand-responsive and conventional transit systems...
Rendiconti Online della Società Geologica Italiana, 2018
Engineering Risk in Natural Resources Management, 1994
The infinite horizon, optimal design problem of a water resources system is analyzed first under ... more The infinite horizon, optimal design problem of a water resources system is analyzed first under the assumption that the hydrometeorologic inflow process is cyclostationary, and then under the assumption that it is non-stationary. It is shown that in the second case, even if an optimal solution is proved to exist, it cannot be determined. It is finally shown how a near-stationarity assumption can provide a pragmatic solution and that it leads to two alternative inflow models: a stochastic or a setmembership model. It is finally shown how the design problem can be solved when the first model is adopted.
Water Resources Research, 1981
A simple procedure is proposed for the determination of the water supplies and demands which maxi... more A simple procedure is proposed for the determination of the water supplies and demands which maximize the total net benefit from water use in a region. The technique is in some ways a standard iterative market method, and, in fact, the convergence to the optimal solution is achieved when the marginal benefit at each demand point is equal to the marginal cost of delivering water to that point. The possibility of applying this technique to a given problem can immediately be ascertained from the pattern of the links between supply and demand units. An example is presented in which the method is applied to analyze the possible interbasin water transfer in the Northwest Water Plan in Mexico. mine the optimal interbasin water transfers in the Northwest sary conditions for optimality imply that Water Plan in Mexico, and section 6 presents concluding remarks. d
Developments in Integrated Environmental Assessment, 2007
Publisher Summary An evaluation criterion is an attribute or a factor through which the performan... more Publisher Summary An evaluation criterion is an attribute or a factor through which the performance of an alternative can be judged with respect to a specific interest. A criterion is not quantitative—that is, it does not define a way to measure the satisfaction associated with an alternative. This chapter presents a hierarchy of criteria. In the hierarchy, criteria are ordered according to different hierarchical levels, beginning with the criterion that was originally proposed (called a “root criterion”) and working down to those criteria (called “leaf criteria”) to which the indicators are associated. The chapter describes the hierarchies that have been defined in the Verbano Project and presents some examples to illustrate how to define them and some of the difficulties that may be encountered. All the indicators that are used in the Verbano Project are defined in the companion website. Once all the evaluation criteria have been defined, the performance of an alternative is described by a vector of indices.
Hydrology and Earth System Sciences Discussions, 2011
In many developing countries water is a key renewable resource to complement carbon-emitting ener... more In many developing countries water is a key renewable resource to complement carbon-emitting energy production and support food security in the face of demand pressure from fast-growing industrial production and urbanization. To cope with undergoing changes, water resources development and management have to be reconsidered by enlarging their scope across sectors and adopting effective tools to analyze current and projected infrastructure potential and operation strategies. In this paper we use multi-objective deterministic and stochastic optimization to assess the current reservoir operation and planned capacity expansion in the Red River Basin (Northern Vietnam), and to evaluate the potential improvement by the adoption of a more sophisticated information system. To reach this goal we analyze the historical operation of the major controllable infrastructure in the basin, the HoaBinh reservoir on the Da River, explore reoperation options corresponding to different tradeoffs among the three main objectives (hydropower production, flood control and water supply), using multi-objective optimization techniques, namely Multi-Objective Genetic Algorithm. Finally, we assess the structural system potential and the need for capacity expansion by application of Deterministic Dynamic Programming. Results show that the current operation can only be relatively improved by advanced optimization techniques, while investment should be put into enlarging the system storage capacity and exploiting additional information to inform the operation.
Water Resources Research, 2011
Recent work has demonstrated the utility of interactive response surfaces in integrating decision... more Recent work has demonstrated the utility of interactive response surfaces in integrating decision making and complex process-based modeling of environmental systems. Specifically, we focus on problems that require computationally expensive dynamic models where a limited number of simulations are possible and so traditional meta-modeling might be not an option for the optimization process. Within this constraint, the interactive global response surface method aims to develop a complete picture of how the system responds to a planning decision on the basis of a restricted number of simulations. The interactive local response surface method utilizes the current best alternative to determine improvements on the basis of relatively small changes in the current decision. We outline the use of both methods to a real example of remediation in a water supply reservoir, demonstrating the key advantages and disadvantages of each method and describe a new, interactive cascade approach that provides an improved solution to the problem.
Environmental Modelling & Software, 2012
Mathematical models have been intensively used to support Decision Makers (DMs) in water resource... more Mathematical models have been intensively used to support Decision Makers (DMs) in water resources planning and management. Quantitative information about the effects of a planned intervention (e.g. the installation of impellers in a lake to increase vertical mixing and thus hypolimnetic oxygenation) can be obtained via simulation (the so called what if or scenario analysis). Combining the use of simulation models and the definition of evaluation criteria enables a rigorous, quantitative comparison of different interventions, the prediction of trade-offs between different uses of water and, ultimately, the identification of the Pareto-efficient solutions. However, with the growth in the number of interventions to be considered (e.g., not only impellers, but also combinations of multiple technologies such as impellers, mixers, oxygenators, selective withdrawal) and the necessity to fix their design parameters (e.g., not only deciding whether impellers must be installed or not, but also defining their number, location, thrust and depth) an exhaustive comparison becomes impracticable. In this case, Pareto-efficient solutions must be searched for by means of an automatic selection procedure based on methods from optimization theory (e.g., gradient-based algorithms, genetic algorithms, reinforcement learning). Unfortunately, optimization methods suffer from well known computational limits and, as the complexity of the simulation model increases, they quickly become impracticable. This is the case with the distributed-parameters, process based models traditionally used to describe the hydrodynamic and biochemical conditions of water bodies. For instance, the model used in this study to simulate hydrodynamics and ecological processes in a 1.21 x 10 6 m 3 volume reservoir has a real-torun time ratio associated of 30:1 and comprises 33 x 10 4 spatially distributed state variables. To overcome this difficulty in this paper we develop and apply a procedural approach based on the iterative approximation of the function (Response Surface) mapping the alternatives (defined by a vector of design parameters such as number and position of impellers) into DM's satisfaction to identify Pareto-efficient interventions. An initial, small set of alternatives is simulated through a 3D coupled hydrodynamic-ecological model (ELCOM-CAEDYM) and their effects on the DM's satisfaction are evaluated in term of physical indicators. Using an appropriate class of functions (e.g linear interpolators, neural networks), a first approximation of the response surface is generated based on the data from simulation. The identification of Pareto-efficient solutions is performed using such approximation. Through a heuristic algorithm, interesting Paretian points are chosen and the corresponding points in the space of the alternatives obtained by inverting the response surfaces. These new alternatives are then simulated using the 3D model to enlarge the sample data set over which the Response Surface is identified and the procedure repeated until a given termination test is satisfied. The approach is demonstrated through a case study in Australia, the rehabilitation of the water quality in the Googong reservoir, the main freshwater reservoir of the city of Canberra. The reservoir is affected by high concentrations of Manganese and Cyanobacteria causing severe problems to the quality of water supply and the recreational use of the water body. Destratification was thought as a suitable way to solve these problems and 2 pairs of mixers were installed in 2007. With the approach proposed new mixers configurations (position and number) have been found that significantly improve the current solution.
Agricultural Water Management, 2010
Complex decision-making problems, related to planning and management of irrigation water resource... more Complex decision-making problems, related to planning and management of irrigation water resources, generally preclude the use of large, distributed-parameter models, which are then commonly substituted by lumped-parameter models. This paper, with the aim of improving the quality of these latter, introduces a new approach for their design. This approach is based on metamodelling, which proposes to identify a simple, lumped-parameter model on the basis of the data produced via simulation with a distributed-parameter model. The approach proposed is tested on a real-world case study, namely the identification of a metamodel describing the water demand of the Muzza-Bassa Lodigiana irrigation district (Italy). The metamodel, which inherits the physical description of the original distributedparameter model, is sufficiently simple to permit the resolution of an optimal control problem, i.e. the design, via stochastic dynamic programming, of the release policy of Lake Como, serving the Muzza irrigation district.
Environmental Research Letters, 2016
Multidimensional stress test for hydropower investments facing climate, geophysical and financial... more Multidimensional stress test for hydropower investments facing climate, geophysical and financial uncertainty Patrick A. Ray et al
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Papers by Rodolfo Soncini Sessa