@article{GonzalezGrandonHeitschHenrion2017, author = {Gonzalez Grandon, Tatiana and Heitsch, Holger and Henrion, Rene}, title = {A joint model of probabilistic/robust constraints for gas transport management in stationary networks}, series = {Computational Management Science}, volume = {14}, journal = {Computational Management Science}, doi = {10.1007/s10287-017-0284-7}, pages = {443 -- 460}, year = {2017}, abstract = {We present a novel mathematical algorithm to assist gas network operators in managing uncertainty, while increasing reliability of transmission and supply. As a result, we solve an optimization problem with a joint probabilistic constraint over an infinite system of random inequalities. Such models arise in the presence of uncertain parameters having partially stochastic and partially non-stochastic character. The application that drives this new approach is a stationary network with uncertain demand (which are stochastic due to the possibility of fitting statistical distributions based on historical measurements) and with uncertain roughness coefficients in the pipes (which are uncertain but non-stochastic due to a lack of attainable measurements). We study the sensitivity of local uncertainties in the roughness coefficients and their impact on a highly reliable network operation. In particular, we are going to answer the question, what is the maximum uncertainty that is allowed (shaping a 'maximal' uncertainty set) around nominal roughness coefficients, such that random demands in a stationary gas network can be satisfied at given high probability level for no matter which realization of true roughness coefficients within the uncertainty set. One ends up with a constraint, which is probabilistic with respect to the load of gas and robust with respect to the roughness coefficients. We demonstrate how such constraints can be dealt with in the framework of the so-called spheric-radial decomposition of multivariate Gaussian distributions. The numerical solution of a corresponding optimization problem is illustrated. The results might assist the network operator with the implementation of cost-intensive roughness measurements.}, language = {en} } @article{AdelhuetteAssmannGonzalezGrandonetal.2017, author = {Adelh{\"u}tte, Dennis and Aßmann, Denis and Gonz{\`a}lez Grand{\`o}n, Tatiana and Gugat, Martin and Heitsch, Holger and Liers, Frauke and Henrion, Ren{\´e} and Nitsche, Sabrina and Schultz, R{\"u}diger and Stingl, Michael and Wintergerst, David}, title = {Joint model of probabilistic/robust (probust) constraints applied to gas network optimization}, doi = {10.1007/s10013-020-00434-y}, year = {2017}, abstract = {Optimization tasks under uncertain conditions abound in many real-life applications. Whereas solution approaches for probabilistic constraints are often developed in case the uncertainties can be assumed to follow a certain probability distribution, robust approaches are usually used in case solutions are sought that are feasible for all realizations of uncertainties within some pre-defined uncertainty set. As many applications contain different types of uncertainties that require robust as well as probabilistic treatments, we deal with a class of joint probabilistic/robust constraints as its appears in optimization problems under uncertainty. Focusing on complex uncertain gas network optimization problems, we show the relevance of this class of problems for the task of maximizing free booked capacities in an algebraic model for a stationary gas network. We furthermore present approaches for their solution. Finally, we study the problem of controlling a transient system that is governed by the wave equation. The task consists in determining controls such that a certain robustness measure remains below some given upper bound, with high probability.}, language = {en} }