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INFORMS Nashville – 2016

127

4 - Robust Empirical Optimization

Andrew Lim, National University of Singapore, Singapore,

Singapore,

andrewlim@nus.edu.sg

, Jun-ya Gotoh,

Michael Jong Kim

We analyze the out-of-sample performance of robust empirical optimization and

show that it asymptotically optimizes the mean-variance reward under the data

generating model. We also introduce the notion of robust cross-validation as a

method of calibrating the empirical robust optimization problem. Theoretical and

experimental comparison to empirical optimization is also provided.

MA17

105B-MCC

Optimizing Power System Operations

Under Uncertainty

Sponsored: Optimization, Optimization Under Uncertainty

Sponsored Session

Chair: Yu Zhang, University of California, Berkeley, 200 California Hall,

Albany, CA, 94720, United States,

yuzhang49@berkeley.edu

1 - Unit Commitment Under Gas-supply Uncertainty And

Gas-price Variability

Antonio J. Conejo, The Ohio State University, 1971 Neil Av.,

Columbus, OH, 43210, United States,

conejonavarro.1@osu.edu

Ramteen Sioshansi, Bining Zhao

We propose a two-stage stochastic optimization model to analyze the scheduling

of power units under natural gas-supply uncertainty and natural gas-price

variability. The first stage of this model represents the day-ahead scheduling stage,

while the second stage represents real-time operations via scenarios. We use this

model to analyze the effect of two types of gas-supply conditions. First, we

analyze a case involving low-cost gas supply with gas-transmission issues. We

then examine a case involving higher-cost gas supply, which is used solely to

attain feasibility with fast ramping events.

2 - Stochastic Market Clearing With High-penetration Wind Power

Yu Zhang, University of California, Berkeley,

yuzhang49@berkeley.edu

, Georgios Giannakis

Integrating renewable energy into the modern power grid requires risk-cognizant

dispatch of resources to account for the stochastic availability of renewables.

Toward this goal, day-ahead stochastic market clearing with high-penetration

wind energy is pursued in this work. The objective is to minimize the social cost,

which consists of conventional generation costs, end-user disutility, and a risk

measure of the system re-dispatching cost based on the conditional value-at-risk.

The resulting convex optimization problem is solved via the sample average and

the alternating direction method of multipliers. Numerical results corroborate the

merits of the proposed approaches.

3 - Integrated Generator Maintenance And Operations Scheduling

Under Uncertain Failure Times

Beste Basciftci, Georgia Institute of Technology, Atlanta, GA,

United States,

beste.basciftci@gatech.edu

Murat Yildirim, Shabbir Ahmed, Nagi Gebraeel

In this study, we formulate an integrated generator maintenance and operations

scheduling problem as a stochastic mixed integer program by considering

unexpected failure times. We generate failure scenarios based on the remaining

life time distributions of the generators. We adopt a scenario decomposition

approach to solve this problem in a distributed framework that identifies and

evaluates solutions by solving scenario subproblems. Finally, we present

computational experiments demonstrating the effectiveness of the approach.

MA18

106A-MCC

Theory of Integer Optimization

Sponsored: Optimization, Integer and Discrete Optimization

Sponsored Session

Chair: Alberto Del Pia, University of Wisconsin, Madison,

Madison, WI, United States,

delpia@wisc.edu

1 - Facet Separation With One Linear Program

Laurence Wolsey, Université catholique de Louvain,

laurence.wolsey@uclouvain.be

, Michele Conforti

Given polyhedron P and and a point x*, the separation problem for polyhedra

asks to certify that x* in P and if not, to determine an inequality that is satisfied

by P and violated by x*. This problem is central in cutting plane methods for

Integer Programming and the “quality” of the violated inequality is an essential

feature in the performance of such methods. In this talk we address the problem

of finding efficiently an inequality that is violated by x* and either defines an

improper face or a facet of P. We provide some evidence that our method works

on structured and unstructured problems.

2 - Ellipsoidal Mixed-Integer Representability

Jeffrey Poskin, University of Wisconsin - Madison, Wisconsin, WI,

United States,

poskin@wisc.edu

, Alberto Del Pia

Representability results for mixed-integer linear systems play a fundamental role

in optimization since they give geometric characterizations of the feasible sets that

can be formulated by mixed-integer linear programming. We consider a natural

extension of mixed-integer linear systems obtained by adding just one ellipsoidal

inequality. The set of points that can be described, possibly using additional

variables, by these systems are called ellipsoidal mixed-integer representable. In

this work, we give geometric conditions that characterize ellipsoidal mixed-

integer representable sets. “

MA19

106B-MCC

Evaluating the Performance of Optimization Solvers

Sponsored: Computing

Sponsored Session

Chair: Paul Brooks, Virginia Commonwealth Univ, Virginia

Commonwealth Univ, Richmond, VA, 00000, United States,

jpbrooks@vcu.edu

1 - IPET: Interactive Performance Evaluation Tools For Benchmarking

Optimization Software

Gregor Hendel, ZIB,

hendel@zib.de

The optimization community has recently seen an increasing number of non-

standard benchmark measures for evaluating solver performance, which some

data processing tools do not deliver. The benchmark evaluation starting from the

parsing of raw solver log data until the preparation of publication-ready tables can

be time-consuming and error-prone if done by hand. In this talk, we will first

review some of the specialized benchmark measures used for optimization

software. We will then present a Python tool named IPET to speed-up repetitive

tasks during benchmarking. We will give an overview of the tool and show

examples how automated benchmark scripts can be created using IPET.

2 - Surrogate Models For Algorithm Configuration

Meinolf Sellmann, IBM Research, Yorktown Heights, NY,

United States,

meinolf@us.ibm.com

Automatic algorithm configurators are important tools for improving program

performance. Local search approaches in particular have proven very effective for

tuning. We study the use of non-parametric models in the context of population-

based algorithm configurators. We introduce a model designed specifically for the

task of predicting high-performance regions in the parameter space. Moreover,

we introduce the ideas of genetic engineering of offspring. Numerical results show

that model-based genetic algorithms significantly improve our ability to

effectively configure algorithms automatically.

3 - Tuning Of Optimization Software Parameters For Mixed Integer

Programming Problems

Toni P Sorrell, Virginia Commonwealth University, Richmond, VA,

United States,

tpsorrel@vcu.edu

, Paul Brooks, David Edwards

The tuning of optimization software is of key interested to researchers solving

mixed integer programming (MIP) problems because the efficiency of the

optimization software is can be greatly impacted by the solver’s parameter settings

and the structure of the MIP. A designed experiment approach is used to fit a

model that would suggest settings of the parameters that provided the greatest

impact on the primal integral. Primarily, this research focuses on using classes of

MIPs to not only obtain good parameter settings for a practitioner to use on

future instances of the same class of MIPs, but to also gain understanding of why

the settings work well for that class of MIPs.

4 - Deploying MPL Optimization Models With Google

Web Services API’s

Bjarni Kristjansson, President, Maximal Software Inc., 2111

Wilson Boulevard, Suite 700, Arlington, VA, 22201, United States,

bjarni@maximalsoftware.com

Over the past decade the IT has been moving steadfastly towards utilizing

software on clouds using Web Services API’s. The old standard way of deploying

software on standalone computers is slowly going away. Google has been one of

the leading software vendors in this area and publishes several web API’s which

can be quite useful for deploying optimization applications. In this presentation

we will demonstrate several Google API’s, including the Google Sheets API,

Google Maps API, and Google Visualization API and show how they can be

integrated with the MPL OptiMax Library for deploying optimization to service

both web and mobile clients.

MA19