Month: May 2023

Adaptive Importance Sampling Based Surrogation Methods for Bayesian Hierarchical Models, via Logarithmic Integral Optimization

  • Ziyu He
  • Junyi Liu
  • Jong-Shi Pang
    • Categories Constrained Nonlinear Optimization, Nonsmooth Optimization, Stochastic Programming Tags , ,

    We explore Maximum a Posteriori inference of Bayesian Hierarchical Models (BHMs) with intractable normalizers, which are increasingly prevalent in contemporary applications and pose computational challenges when combined with nonconvexity and nondifferentiability. To address these, we propose the Adaptive Importance Sampling-based Surrogation method, which efficiently handles nonconvexity and nondifferentiability while improving the sampling approximation of the … Read more

    Distributionally Robust Linear Quadratic Control

  • Bahar Tașkesen
  • Dan Iancu
  • Çağıl Koçyiğit
  • Daniel Kuhn
    • Categories Control Applications, Dynamic Programming, Robust Optimization

    Linear-Quadratic-Gaussian (LQG) control is a fundamental control paradigm that is studied in various fields such as engineering, computer science, economics, and neuroscience. It involves controlling a system with linear dynamics and imperfect observations, subject to additive noise, with the goal of minimizing a quadratic cost function for the state and control variables. In this work, … Read more

    Sampling-based Decomposition Algorithms for Multistage Stochastic Programming

  • Harsha Gangammanavar
    • Categories Stochastic Programming Tags , , ,

    Sampling-based algorithms provide a practical approach to solving large-scale multistage stochastic programs. This chapter presents two alternative approaches to incorporating sampling within multistage stochastic linear programming algorithms. In the first approach, sampling is used to construct a sample average approximation (SAA) of the true multistage program. Subsequently, an optimization step is undertaken using deterministic decomposition … Read more

    Polyhedral Newton-min algorithms for complementarity problems

  • Jean-Pierre Dussault
  • Mathieu Frappier
  • Jean Charles Gilbert
    • Categories Complementarity and Variational Inequalities Tags , , , , , , , ,

    The semismooth Newton method is a very efficient approach for computing a zero of a large class of nonsmooth equations. When the initial iterate is sufficiently close to a regular zero and the function is strongly semismooth, the generated sequence converges quadratically to that zero, while the iteration only requires to solve a linear system. … Read more

    On the Regulatory and Economic Incentives for Renewable Hybrid Power Plants in Brazil

  • Alexandre Street
    • Categories Energy, Stochastic Programming Tags , , , , ,

    The complementarity between renewable generation profiles has been widely explored in the literature. Notwithstanding, the regulatory and economic frameworks for hybrid power plants add interesting challenges and opportunities for investors, regulators, and planners. Focusing on the Brazilian power market, this paper proposes a unified and isonomic firm energy certificate (FEC) calculation for non-controllable renewable generators, … Read more

    Safely Learning Dynamical Systems

  • Abraar Chaudhry
  • Amir Ali Ahmadi
  • Vikas Sindhwani
  • Stephen Tu
    • Categories Control Applications, Linear, Cone and Semidefinite Programming, Robust Optimization Tags , , , ,

    A fundamental challenge in learning an unknown dynamical system is to reduce model uncertainty by making measurements while maintaining safety. In this work, we formulate a mathematical definition of what it means to safely learn a dynamical system by sequentially deciding where to initialize the next trajectory. In our framework, the state of the system … Read more

    Political districting to optimize the Polsby-Popper compactness score with application to voting rights

  • Pietro Belotti
  • Austin Buchanan
  • Soraya Ezazipour
    • Categories (Mixed) Integer Nonlinear Programming, Applications - OR and Management Sciences, Integer Programming Tags , ,

    In the academic literature and in expert testimony, the Polsby-Popper score is the most popular way to measure the compactness of a political district. Given a district with area \(A\) and perimeter \(P\), its Polsby-Popper score is given by \( (4 \pi A)/P^2\). This score takes values between zero and one, with circular districts achieving … Read more

    On the equilibrium prices of a regular locally Lipschitz exchange economy

  • Xuan Duc Ha Truong
    • Categories Applications - OR and Management Sciences, Finance and Economics Tags , , , , , ,

    We extend classical results by Debreu and Dierker about equilibrium prices of a regular economy with continuously differentiable demand functions/excess demand function to a regular exchange economy with these functions being locally Lipschitz. Our concept of a regular economy is based on Clarke’s concept of regular value and we show that such a regular economy … Read more

    Asynchronous Iterations in Optimization: New Sequence Results and Sharper Algorithmic Guarantees

  • Hamid Reza Feyzmahdavian
  • Mikael Johansson
    • Categories Convex Optimization, Global Optimization, Parallel Algorithms Tags , , , ,

    We introduce novel convergence results for asynchronous iterations that appear in the analysis of parallel and distributed optimization algorithms. The results are simple to apply and give explicit estimates for how the degree of asynchrony impacts the convergence rates of the iterates. Our results shorten, streamline and strengthen existing convergence proofs for several asynchronous optimization … Read more

    A Moment-SOS Hierarchy for Robust Polynomial Matrix Inequality Optimization with SOS-Convexity

  • Jie Wang
  • Feng Guo
    • Categories Global Optimization Applications, Robust Optimization, Semi-definite Programming Tags , , , ,

    We study a class of polynomial optimization problems with a robust polynomial matrix inequality constraint for which the uncertainty set is defined also by a polynomial matrix inequality (including robust polynomial semidefinite programs as a special case). Under certain SOS-convexity assumptions, we construct a hierarchy of moment-SOS relaxations for this problem to obtain convergent upper … Read more