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Fengqi You - One of the best experts on this subject based on the ideXlab platform.

  • Data-Driven Process Network Planning: A Distributionally Robust Optimization Approach
    IFAC-PapersOnLine, 2018
    Co-Authors: Chao Shang, Fengqi You
    Abstract:

    Abstract Process Network planning is an important and challenging task in Process systems engineering. Due to the penetration of uncertainties such as random demands and market prices, stochastic programming and robust optimization have been extensively used in Process Network planning for better protection against uncertainties. However, both methods fall short of addressing the ambiguity of probability distributions, which is quite common in practice. In this work, we apply distributionally robust optimization to handling the inexactness of probability distributions of uncertain demands in Process Network planning problems. By extracting useful information from historical data, ambiguity sets can be readily constructed, which seamlessly integrate statistical information into the optimization model. To account for the sequential decision-making structure in Process Network planning, we further develop multi-stage distributionally robust optimization models and adopt affine decision rules to address the computational issue. Finally, the optimization problem can be recast as a mixed-integer linear program. Applications in industrial-scale Process Network planning demonstrate that, the proposed distributionally robust optimization approach can better hedge against distributional ambiguity and yield rational long-term decisions by effectively utilizing demand data information.

  • unraveling optimal biomass Processing routes from bioconversion product and Process Networks under uncertainty an adaptive robust optimization approach
    ACS Sustainable Chemistry & Engineering, 2016
    Co-Authors: Jian Gong, Daniel J Garcia, Fengqi You
    Abstract:

    A bioconversion product and Process Network converts different types of biomass to various fuels and chemicals via a plethora of technologies. Reliable bioconversion Processing pathways should be designed considering the effect of uncertain parameters, such as biomass feedstock price and biofuel product demand. Given a large-scale bioconversion product and Process Network of 194 technologies and 139 materials/compounds, we propose a two-stage adaptive robust mixed-integer nonlinear programming problem. The model allows for decisions at the design and operational stages to be made sequentially and considers budgets of uncertainty to control the level of robustness. Nonlinearity in this model appears in the first-stage objective function, and the second-stage problem is a linear program. We efficiently solve the proposed problem with a tailored algorithm. The robust optimal solutions corresponding to various uncertainty budgets show that the minimum total annualized cost is more sensitive to biofuel demand ...

Sjoerd Meijer - One of the best experts on this subject based on the ideXlab platform.

  • Transformations for polyhedral Process Networks
    2010
    Co-Authors: Sjoerd Meijer
    Abstract:

    We use the polyhedral Process Network (PPN) model of computation to program and map streaming applications onto embedded Multi-Processor Systems on Chip (MPSoCs) platforms. The PPNs, which can be automatically derived from sequential program applications, do not necessarily meet the performance/resource constraints. A designer can therefore apply the Process splitting transformations to increase program performance, and the Process merging transformation to reduce the number of Processes in a PPN. These transformations were defined, but a designer had many possibilities to apply a particular transformation, and these transformations can also be ordered in many different ways. In this dissertation, we define compile-time solution approaches that assist the designer in evaluating and applying Process splitting and merging transformations in the most effective way.

  • DATE - Interactive presentation: A Process splitting transformation for Kahn Process Networks
    2007
    Co-Authors: Sjoerd Meijer, Alexandru Turjan, Bart Kienhuis, Erwin De Kock
    Abstract:

    In this paper we present a Process splitting transformation for Kahn Process Networks. Running applications written in this parallel program specification on a multiProcessor architecture does not guarantee that the runtime requirements are met. Therefore, it may be necessary to further analyze and optimize Kahn Process Networks. In this paper, we will present a four-step transformation that results in a functionally equivalent Process Network, but with a changed and optimized Network structure. The class of Networks that can be handled is not restricted to static Networks. The novelty of this approach is that it can also handle Processes with dynamic program statements. We will illustrate the transformation prototyped in GCC for a JPEG decoder, showing a 21% performance improvements.

  • A Process Splitting Transformation For Kahn Process Networks
    2007 Design Automation & Test in Europe Conference & Exhibition, 2007
    Co-Authors: Sjoerd Meijer, Alexandru Turjan, Bart Kienhuis, E. De Kock
    Abstract:

    This paper presents a Process splitting transformation for Kahn Process Networks. Running applications written in this parallel program specification on a multiProcessor architecture does not guarantee that the runtime requirements are met. Therefore, it may be necessary to further analyze and optimize Kahn Process Networks. This paper presents a four-step transformation that result in a functionally equivalent Process Network, but with a changed and optimized Network structure. The class of Networks that can be handled is not restricted to static Networks. The novelty of this approach is that it can also handle Processes with dynamic program statements. The authors illustrate the transformation prototyped in GCC for a JPEG decoder, showing a 21% performance improvements

Francesco Fusco - One of the best experts on this subject based on the ideXlab platform.

  • Chapter 5 Wire-Speed Hardware-Assisted Traffic Filtering with Mainstream Network Adapters
    2011
    Co-Authors: Luca Deri, Joseph Gasparakis, Peter P. Waskiewicz, Francesco Fusco
    Abstract:

    Modern computer architectures are founded on multi-core Processors. In order to efficiently Process Network traffic, it is necessary to dynamically split high-speed packet streams across cores based on the monitoring goal. Most Network adapters are multi-core aware but offer limited facilities for assigning packets to Processor cores. In this paper we introduce a hybrid traffic analysis framework that leverages flexible packet balancing mechanisms available on recent 10 Gbit commodity Network adapters not yet exploited by operating systems. The main contribution of this paper is an open source hardware-assisted software layer for dynamically configuring packet balancing policies in order to fully exploit multi-core systems and enable 10 Gbit wire-speed Network traffic analysis.

  • Wire-Speed Hardware-Assisted Traffic Filtering with Mainstream Network Adapters
    Advances in Network-Embedded Management and Applications, 2010
    Co-Authors: Luca Deri, Joseph Gasparakis, Peter P. Waskiewicz, Francesco Fusco
    Abstract:

    Modern computer architectures are founded on multi-core Processors. In order to efficiently Process Network traffic, it is necessary to dynamically split high-speed packet streams across cores based on the monitoring goal. Most Network adapters are multi-core aware but offer limited facilities for assigning packets to Processor cores. In this paper we introduce a hybrid traffic analysis framework that leverages flexible packet balancing mechanisms available on recent 10 Gbit commodity Network adapters not yet exploited by operating systems. The main contribution of this paper is an open source hardware-assisted software layer for dynamically configuring packet balancing policies in order to fully exploit multi-core systems and enable 10 Gbit wire-speed Network traffic analysis.

Ignacio E Grossmann - One of the best experts on this subject based on the ideXlab platform.

  • scheduling and feed quality optimization of concentrate raw materials in the copper refining industry
    Industrial & Engineering Chemistry Research, 2018
    Co-Authors: Yingkai Song, Brenno C Menezes, Pablo Garciaherreros, Ignacio E Grossmann
    Abstract:

    Scheduling and feed quality optimization for Processing solid concentrates in the copper refining industry may be formulated as a large-scale, discrete-time, nonconvex mixed-integer nonlinear program (MINLP) by including logistics operations and ad-hoc blending constraints. However, to solve this complex problem, the full space MINLP for the blending of solid concentrates of copper and the scheduling of their logistics is partitioned into a mixed-integer linear program (MILP) and a nonlinear program (NLP). The solution strategy considers the relax-and-fix rolling horizon with nearby time window overlaps and the use of multiple MILP solutions applied in a two-step MILP–NLP procedure. Two models are proposed for the flowsheet balances: a split fraction model and a Process Network model. The results indicate that the split fraction model yields near optimal solutions with a large computational effort, whereas the Process Network can generate several feasible solutions faster. We present a motivating example ...

  • optimal procurement contract selection with price optimization under uncertainty for Process Networks
    Computers & Chemical Engineering, 2015
    Co-Authors: Bruno A Calfa, Ignacio E Grossmann
    Abstract:

    Abstract In this work, we propose extending the production planning decisions of a chemical Process Network to include optimal contract selection under uncertainty with suppliers and product selling price optimization. We use three quantity-based contract models: discount after a certain purchased amount, bulk discount, and fixed duration contracts. We propose the use of general regression models to describe the relationship between selling price, demand, and possibly other predictors, such as economic indicators. For illustration purposes, we consider three demand-response models (i.e., selling price as a function of demand) that are typically encountered in the literature: linear, constant-elasticity, and logit. We develop a mixed-integer nonlinear two-stage stochastic programming that accounts for uncertainty in both supply (e.g., raw material spot market price) and demand (random nature of the residuals of the regression models) for the planning of the Process Network. The proposed method is illustrated with two numerical examples of chemical Process Networks.

  • review of nonlinear mixed integer and disjunctive programming techniques
    Optimization and Engineering, 2002
    Co-Authors: Ignacio E Grossmann
    Abstract:

    This paper has as a major objective to present a unified overview and derivation of mixed-integer nonlinear programming (MINLP) techniques, Branch and Bound, Outer-Approximation, Generalized Benders and Extended Cutting Plane methods, as applied to nonlinear discrete optimization problems that are expressed in algebraic form. The solution of MINLP problems with convex functions is presented first, followed by a brief discussion on extensions for the nonconvex case. The solution of logic based representations, known as generalized disjunctive programs, is also described. Theoretical properties are presented, and numerical comparisons on a small Process Network problem.

E. De Kock - One of the best experts on this subject based on the ideXlab platform.

  • A Process Splitting Transformation For Kahn Process Networks
    2007 Design Automation & Test in Europe Conference & Exhibition, 2007
    Co-Authors: Sjoerd Meijer, Alexandru Turjan, Bart Kienhuis, E. De Kock
    Abstract:

    This paper presents a Process splitting transformation for Kahn Process Networks. Running applications written in this parallel program specification on a multiProcessor architecture does not guarantee that the runtime requirements are met. Therefore, it may be necessary to further analyze and optimize Kahn Process Networks. This paper presents a four-step transformation that result in a functionally equivalent Process Network, but with a changed and optimized Network structure. The class of Networks that can be handled is not restricted to static Networks. The novelty of this approach is that it can also handle Processes with dynamic program statements. The authors illustrate the transformation prototyped in GCC for a JPEG decoder, showing a 21% performance improvements