Papers by Stratos Pistikopoulos
Abstract In the present work, the role of stochastic Monte Carlo simulations as an efficient comp... more Abstract In the present work, the role of stochastic Monte Carlo simulations as an efficient computational tool for the simulation of multi-variate physico-chemical systems, within the general framework of population balances, is presented.
Abstract We propose a stochastic algorithm for the global optimization of chance constrained prob... more Abstract We propose a stochastic algorithm for the global optimization of chance constrained problems. We assume that the probability measure with which the constraints are evaluated is known only through its moments. The algorithm proceeds in two phases. In the first phase the probability distribution is (coarsely) discretized and solved to global optimality using a stochastic algorithm. We only assume that the stochastic algorithm exhibits a weak* convergence to a probability measure assigning all its mass to the discretized problem.
This work presents a compartmental model for delivery of drugs under anesthesia and an advanced m... more This work presents a compartmental model for delivery of drugs under anesthesia and an advanced model based control algorithm for insulin delivery for Type 1 diabetes. The model for anesthesia involves choice of three drugs isoflurane, dopamine and sodium nitroprusside, which allows simultaneous regulation of mean arterial pressure and unconsciousness of the patients. A number of dynamic simulations are carried out to validate the model.
Abstract A new type of process simulation course is presented.
Abstract: This paper proposes a temperature controller for PEM fuel cell systems with an air blow... more Abstract: This paper proposes a temperature controller for PEM fuel cell systems with an air blower as thermal circuit. The objective of this controller is to maintain the stack temperature over a given set-point which is obtained from the results of a real-time optimization algorithm with the goal of minimizing the stack degradation and maximizing the global efficiency. An Explicit MPC is proposed to deal with this control problem which presents delays, the critical sampling time, constraints and disturbances.
Abstract This article presents a new framework, based on parametric programming, that unifies the... more Abstract This article presents a new framework, based on parametric programming, that unifies the solution of the various flexibility analysis and design optimization problems that arise for linear, convex, and nonconvex, nonlinear systems with deterministic or stochastic uncertainties. This approach generalizes earlier work by Bansal et al.
Abstract A new network representation to study the impact of capital and research & development (... more Abstract A new network representation to study the impact of capital and research & development (R&D) investment decisions on the evolution of biomass to commodity chemicals technologies is presented. The corresponding mathematical programming formulation is developed. The model is solved for a simplified ethylene production scenario to demonstrate its ability to predict the capacity expansion and R&D investment decisions. Keywords: biomass to commodity chemicals, optimization, technology evolution.
Polygeneration, a multiple-input, multiple-output energy system that produces electricity and che... more Polygeneration, a multiple-input, multiple-output energy system that produces electricity and chemicals, is one potential energy conversion technology, which is both cost-effective and environmental friendly, hence providing an alternative towards meeting worldwide increasing energy demands and environmental constraints simultaneously. Detailed discussions of polygeneration energy systems can be found in [1, 2].
Abstract: In this work a compartmental model for delivery of three drugs (isoflurane, dopamine an... more Abstract: In this work a compartmental model for delivery of three drugs (isoflurane, dopamine and sodium nitroprusside) for anesthesia is presented. The key feature of this model is that mean arterial pressure and unconsciousness of the patient can be simultaneously regulated. A number of dynamic simulation experiments are carried out for the validation of the model.
Abstract. Process operations often involve transitions between operating modes, which are typical... more Abstract. Process operations often involve transitions between operating modes, which are typically described by their own dynamic models, constraints and specifications. Developing a formal theoretical framework and efficient computational tools to deal with such operational issues pose a formidable challenge.
Abstract We present an analytical dynamic model and a general framework for the optimal design an... more Abstract We present an analytical dynamic model and a general framework for the optimal design and control of a PEM fuel cell system. The mathematical model includes detailed model for the PEM fuel cell stack and simplified models for the compressor, humidifier and cooling system. The framework features (i) a detailed dynamic process model, and (ii) an explicit/multi-parametric model predictive controller design step.
Linear systems with input, output, or state constraints are probably the most important class of ... more Linear systems with input, output, or state constraints are probably the most important class of systems in practice and the most studied as well. Although, a variety of control design methods have been developed for linear systems, it is widely accepted that stability and good performance for these systems, especially in the presence of constraints, is guaranteed with a nonlinear control law.
In this paper we present recent advances in multiparametric nonlinear programming (mp-NLP) algori... more In this paper we present recent advances in multiparametric nonlinear programming (mp-NLP) algorithms for explicit nonlinear model predictive control (mp-NMPC). Three mp-NLP algorithms for NMPC are discussed, based on which novel mp-NMPC controllers are derived. The performance of the explicit controllers are then tested and compared in a simulation example involving the operation of a continuous stirred-tank reactor (CSTR).
Abstract In this paper, we outline the foundation of a general global optimisation strategy for t... more Abstract In this paper, we outline the foundation of a general global optimisation strategy for the solution of multilevel hierarchical and general decentralised multilevel problems based on our recent developments in multiparametric programming theory. The core idea is to recast each optimisation subproblem in the multilevel hierarchy as a multiparametric programming problem and the transform the multilevel problem into a single-level optimisation problem.
Abstract The complexity of the regulatory network and the interactions that occur in the intracel... more Abstract The complexity of the regulatory network and the interactions that occur in the intracellular environment of microorganisms highlight the importance in developing tractable mechanistic models of cellular functions and systematic approaches for modelling biological systems. To this end, the existing process systems engineering approaches can serve as a vehicle for understanding, integrating and designing biological systems and processes.
Abstract In this paper, we outline the foundations of a general global optimisation strategy for ... more Abstract In this paper, we outline the foundations of a general global optimisation strategy for the solution of multilevel hierarchical and general decentralised multilevel problems, based on our recent developments on multi-parametric programming and control theory. The core idea is to recast each optimisation subproblem, present in the hierarchy, as a multi-parametric programming problem, with parameters being the optimisation variables belonging to the remaining subproblems.
Abstract In previous work, we extended the analysis of control structures based upon full process... more Abstract In previous work, we extended the analysis of control structures based upon full process models to include the dynamic performance in a consistent manner. In our approach, NMPC-controllers are assumed to avoid the problem of comparison between control structures where the dynamic performance depends on the type and the parameterization of the controllers that are used.
The majority of models describing the kinetic properties of a microorganism for a given substrate... more The majority of models describing the kinetic properties of a microorganism for a given substrate are unstructured and empirical. They are formulated in this manner so that the complex mechanism of cell growth is simplified. Herein, a novel approach for modelling microbial growth kinetics is proposed, linking biomass growth and substrate consumption rates to the gene regulatory programmes that control these processes.
Abstract Dynamic oil and gas production systems simulation and optimization is a research trend w... more Abstract Dynamic oil and gas production systems simulation and optimization is a research trend with a potential to meet the challenges faced by the international oil and gas industry, as has been already demonstrated in a wide variety of publications in the open literature. The complex two-phase flow in reservoirs and production wells governs fuel transport, but is mostly handled by algebraic approximations in modern optimization applications; the true reservoir state variable profiles (initial/boundary conditions) are not known.
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Papers by Stratos Pistikopoulos