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INFORMS Nashville – 2016

212

4 - Diameter-constrained Lambda-edge-connected

K-subgraph Problem

Yongying Zhou, University of Arizona,

yongyingz@email.arizona.edu

In this talk, we study the diameter-constrained lambda-edge-connected

k-subgraph problem, or the DC (k, lambda)-subgraph problem. Besides the

requirements on the number of the vertices and edge connectivity, the subgraph

has a diameter limit. This problem is a generalization of (k, lambda)-subgraph

problem and diameter constrained minimum spanning tree. Commodity flow-

based and hop constrained formulations are established, which are both integer

programming (IP) formulation. Additionally, numerical experiments are

performed to compare all proposed IP formulation.

MD12

104B-MCC

Mixed Integer Programming Formulations

and Applications

Sponsored: Optimization, Integer and Discrete Optimization

Sponsored Session

Chair: Juan Pablo Vielma, Massachusetts Institute of Technology,

Cambridge, MA, United States,

jvielma@mit.edu

1 - Small Independent Branching Formulations For Unions

Of V-polyhedra

Joey Huchette, Massachusetts Institute of Technology, Cambridge,

MA, United States,

huchette@mit.edu

, Juan Pablo Vielma

We present a framework for constructing small, strong mixed-integer

formulations for disjunctive constraints. Our approach is a generalization of the

logarithmically-sized formulations of Vielma and Nemhauser for SOS2

constraints, and we offer a complete characterization of its expressive power. We

apply the framework to a variety of disjunctive constraints, producing novel,

small, and strong formulations for outer approximations of multilinear terms,

generalizations of special ordered sets, piecewise linear functions over a variety of

domains, and collision avoidance constraints.

2 - Embedding Formulations For Unions Of Convex Bodies

Juan Pablo Vielma, MIT,

jvielma@mit.edu

In this talk we extend to the non-polyhedral setting a systematic procedure to

construct non-extended ideal formulations for unions of polyhedral introduced in

Vielma (2015). Using geometric tools from the study of Minkoswki sums we show

that the procedure can be used to recover and extend several special purpose

non-extended ideal formulations. We also illustrate how the tools can be used to

prove that no polynomially constrained non-extended ideal formulation can be

obtained for some simple convex quadratic sets.

3 - Winning Daily Fantasy Sports Hockey Contests Using Integer

Programming

Scott Hunter, MIT,

dshunter@mit.edu

, Juan Pablo Vielma,

Tauhid Zaman

We present an integer programming (IP) approach to winning daily fantasy sports

hockey contests which have top heavy payoff structures. Our approach

incorporates publicly available predictions into a series of IPs that compute

optimal lineups. We find that the produced lineups perform well in practice and

are able to come in first place in contests with thousands of entries. We also show

through simulations how the profit margin varies with various parameters. Our

approach can easily be extended to other sports, such as American football and

baseball.

4 - Smart Grids Observability Using Bilevel Programming

Claudia D’Ambrosio, Ecole Polytechnique, LIX CNRS (UMR7161),

Palaiseau, France,

dambrosio@lix.polytechnique.fr

Monitoring an electrical network is an important and challenging task. Phasor

measurement units (PMU) are devices that can be used for a state estimation of

this network. We consider a PMU placement problem and propose two new

approaches to model this problem, which take into account a propagation rule

based on Ohm’s and Kirchoff’s laws. First, we describe the natural binary linear

programming model based on an iterative observability process. Then, we remove

the iteration by reformulating its fixed point conditions to a bilevel program,

which we solve with a tailored cutting plane algorithm. Finally, we show

computational evidence of the effectiveness of our method.

MD13

104C-MCC

Project and Resource Planning

Sponsored: Optimization, Computational Optimization and Software

Sponsored Session

Chair: Haitao Li, Univ. of Missouri - St Louis, St Louis, MO,

United States,

lihait@umsl.edu

Co-Chair: Cipriano A. Santos, Distinguished Technologist, HPe-IT

Center of Excellence, Virtual Office, Palo Alto, CA, 94304, United

States,

cipriano.santos@hpe.com

1 - An Optimization Approach To Workforce Planning In Professional

Service Firms

Vincent Hargaden, Assistant Professor, University College Dublin,

209 Engineering & Materials Science Centre, Belfield, Dublin 4,

Ireland,

vincent.hargaden@ucd.ie,

Jennifer K. Ryan, Amir Azaron

We develop a comprehensive mixed integer programming model for the

workforce planning process in professional service firms. We will present results

from the model which show the impact of skill mix, skill capability levels and

cross training on key performance metrics such as project completion rates, staff

utilization and profit. We show how extensions to our base model can incorporate

issues such as a rolling planning horizon approach and variable project start dates.

2 - Simulation -Optimization For Strategic Workforce Planning

Manuel Laguna, University of Colorado Boulder,

laguna@colorado.edu

OptForce is a data analytics tool for workforce planning. We describe how

company data is used to build a simulation model of a workforce. This model is

then used for what-if analysis and optimization. The techniques associated with

this application of simulation-optimization are also discussed.

3 - Talent Optimization For The Knowledge Economy

Cipriano A. Santos, HP Enterprise,

cipriano.santos@hpe.com

Allocating the right talent for the right job at the right time, location, and cost is

critical for the operational efficiency of Professional Services Organizations. In this

talk we present a hierarchical planning approach for labor resources allocations

MD14

104D-MCC

IAAA and Sygenta Reprise

Sponsored: Analytics

Sponsored Session

Chair: Tarun Mohan Lal, Mayo Clinic, 1, Rochester, MN, 12345,

United States,

mohanlal.tarun@mayo.edu

MD15

104E-MCC

Network Modeling and Inference

Sponsored: Artificial Intelligence

Sponsored Session

Chair: Adel Javanmard, Assistant Professor, University of Southern

California, Bridge Hall, 3670 Trousdale Parkway, Los Angeles, CA,

90089, United States,

ajavanma@marshall.usc.edu

1 - Co-clustering Of Non-smooth Graphons

David Sungjun Choi, Carnegie Mellon University,

davidch@andrew.cmu.edu

Theory is becoming known for community detection and network clustering;

however, the results assume an idealized model that is unlikely to hold in many

settings. Here we consider exploratory co-clustering of a bipartite network whose

nodes are sampled from an arbitrary population. This is equivalent to assuming a

nonparametric generative model known as a graphon. We show that clusters

found in the data by any method will extend to the population, or equivalently

that the estimated blockmodel approximates a blocked version of the generative

graphon, with error bounded by n^{-1/2}. Analogous results are also shown for

degree-corrected and random dot product graph models.

MD12