DIAMETER OPTIMIZATION IN MULTIPHASE PIPELINE NETWORK

Multiphase Shape Optimization Problems

This paper is devoted to the analysis of multiphase shape optimization problems, which can formally be written as min { g ( (F1(Ω1), . . . , Fh(Ωh) ) +m ∣∣ h ⋃ i=1 Ωi ∣∣ : Ωi ⊂ D, Ωi ∩ Ωj = ∅}, where D ⊆ R is a given bounded open set, |Ωi| is the Lebesgue measure of Ωi and m is a positive constant. For a large class of such functionals, we analyse qualitative properties of the cells and the int...

Network modeling of multiphase ̄ow in fractures

We develop a pore-scale model of wetting in a single fracture. A variable fracture aperture distribution is represented as a square lattice of conceptual pores connected by throats. We borrow concepts from network modeling of ̄ow in porous media to generate a fracture model that includes the e€ects of ̄ow in wetting layers, snap-o€, and cooperative piston-like advance. Cooperative ®lling accoun...

Cumulative Updating of Network Reliability with Diameter Constraint and Network Topology Optimization

Beyond the Pipeline: Discrete Optimization in NLP

We present a discrete optimization model based on a linear programming formulation as an alternative to the cascade of classifiers implemented in many language processing systems. Since NLP tasks are correlated with one another, sequential processing does not guarantee optimal solutions. We apply our model in an NLG application and show that it performs better than a pipeline-based system.

New Optimization Approach to Multiphase Flow

A new optimization formulation for simulating multiphase flow in porous media is introduced. A locally mass-conservative, mixed finite-element method is employed for the spatial discretization. An unconditionally stable, fully-implicit time discretization is used and leads to a coupled system of nonlinear equations that must be solved at each time step. We reformulate this system as a least squ...