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INFORMS Nashville – 2016

72

SC10

103C-MCC

Advances in Energy Systems Modeling

Sponsored: Energy, Natural Res & the Environment, Energy II Other

Sponsored Session

Chair: Rudolf Gerardus Egging, Norwegian University of Science &

Technology, Trondheim, Trondheim, 00000, Norway,

ruud.egging@iot.ntnu.no

1 - Plug And Abandonment Of Offshore Oil And Gas Fields.

Steffen J. Bakker, Norwegian University of Science and

Technology,

steffen.bakker@iot.ntnu.no

At the end of a wells life-cycle, the well has to be permanently abandoned. This

process is called plug and abandonment (P&A). Decisions in the P&A process

depend heavily on uncertain factors such as oil and gas prices, rig rates or well

states. Moreover, these decisions have to be taken at different levels. In this

presentation we discuss a classification of the P&A process into an operational,

tactical and strategic level. For each of these levels we present a corresponding

model, where we make use of real options theory and the frameworks of integer

and stochastic programming.

2 - Trading Off Demand Side Flexibility Vs. Supply Side Flexibility And

Storage In The Electricity System

Hector Maranon-Ledesma, Norwegian University of Science and

Technology,

hector.maranon-ledesma@iot.ntnu.no

Demand Side Management (DSM) permits a reduction in peak load consumption,

a more adaptable demand of electricity, allowing shuting down high emission

power plants, and the intermittent renewable resources to be better exploited by

the use of flexibility mechanisms.

The EMPIRE electricity sector model is a long-term investment stochastic model.

This model has been improved by including DSM at the operational level. The

contributions of this work are including DSM in a large scale electric system and

highlighting the importance that DSM might acquire in the future European

power system.

3 - The Effect Of Drivers Elasticity On The Optimal Pricing And

Management Of Electric Vehicles Charging

Chiara Bordin, Norwegian University of Science and Technology,

Trondheim, Norway,

chiara.bordin@iot.ntnu.no

, Stig Ødegaard

Ottesen, Asgeir Tomasgard, Siri Bruskeland Ager-Hanssen,

Siri Olimb Myhre

The increasing demand for Electric Vehicles (EV) charging puts pressure on the

power grids as in some situations the power consumption can exceed the grid

capacity. We propose a mathematical model for the indirect control of EV

charging that finds an optimal set of price signals to be sent to the drivers

according to their flexibility. The objective is to satisfy the demand when there is a

capacity lack by minimizing the curtailment of loads and prioritizing the loads

shifting. The key contribution is the use of the elasticity concept to forecast the

drivers reactions to the price signals. Sensitivity analyses are presented to

investigate the elasticity effect on prices and loads management.

4 - Risk Aversion In Imperfect Natural Gas Markets.

Rudolf Gerardus Egging, Norwegian University of Science &

Technology,

ruud.egging@iot.ntnu.no

We consider risk aversion by natural gas supply companies considering

investment in conventional and shale gas resources in a stochastic multi-period

mixed complementarity problem. Uncertainty considered includes political risk

and resource sizes. We consider shale gas investment in Poland and Ukraine in a

realistic market setting in Europe. We discuss investment decisions and profits for

varying levels of risk aversion.

SC11

104A-MCC

Dense Clusters in Network Optimization

Sponsored: Optimization, Network Optimization

Sponsored Session

Chair: Vladimir Stozhkov, University of Florida, 2330 SW Williston Rd,

Apt 2826, Gainesville, FL, 32608, United States,

vstozhkov@ufl.edu

1 - Relative Clique Relaxations In Complex Networks

Vladimir Boginski, University of Central Florida,

Vladimir.Boginski@ucf.edu

Real-world complex networks exhibit clustered structure: certain groups of nodes

(vertices) form “cohesive” or “highly connected” clusters (can also be referred to

as “communities”), which can be rigorously characterized using graph-theoretic

concepts. In this presentation, we will focus on so-called relative clique relaxation

models, which are obtained by relaxing certain metrics that attain their maximum

possible values on a clique: edge density, minimum vertex degree, and vertex

connectivity. We will discuss optimization problems of identifying such clusters in

networks, as well as related asymptotic results on phase transitions in random

graphs.

2 - Robust Network Clusters With Small-world Property

Jongeun Kim, University of Florida, Gainesville, FL,

United States,

kje0510@ufl.edu

, Alexander Veremyev,

Vladimir Boginski, Oleg A Prokopyev

Networks are popular and effective tools for analyzing real-world systems, such as

telecommunication, transportation, and social networks. Network robustness is

one of the important issues, because some undesired failures may affect

connectivity and functionality of a network. The ideal robust cluster in a network

is a clique and clique-relaxation research have been developed in recent decades.

In this talk we will address small-world clusters that are robust but also have

certain natural properties.

3 - Detecting Essential Proteins Using A Novel Star Centrality Metric

Mustafa Can Camur, North Dakota State University, Fargo, ND,

United States,

mcancamur@gmail.com

In this talk, we propose a new centrality metric (referred to as star centrality),

which aims to incorporate information from the closed neighborhood of the node,

rather than strictly from the node itself. More specifically, we turn our focus to

degree centrality and show that in the complex protein-protein interaction

networks it is a naive metric that can lead to misclassifying importance in the

network. We portray the success of the new metric using protein-protein

interaction networks, and investigating the significant difference in the

importance of individual nodes we observe when transitioning from node degree

centrality to star degree centrality.

4 - Estimating The Maximum IUC Using SDP Relaxations

Eugene Lykhovyd, Texas A&M University,

lykhovyd@tamu.edu

,

Sergiy Butenko

If you have a simple, undirected graph, the Independent Union of Cliques (IUC)

problem is to find the maximum subset of vertices, in which every connected

component is a clique. It is known that this problem can be formulated on 3-

uniform hypergraphs as the maximum weak independent set. We propose the

estimates for IUC problem based on different SDP relaxations, extending the

Lov\’asz estimate for the maximum stable set. The comparison of different

approaches is also presented.

SC12

104B-MCC

Convex Relaxations for Nonconvex

Polynomial Optimization

Sponsored: Optimization, Integer and Discrete Optimization

Sponsored Session

Chair: Daniel Bienstock, Columbia University, 116th and Broadway,

New York, NY, 10027, United States,

dano@columbia.edu

1 - LP And SOCP-based Algebraic Relaxations For

Polynomial Optimization

Amir Ali Ahmadi, Princeton University,

a_a_a@princeton.edu

We present ongoing work on solving polynomial optimization problems using

linear and convex relaxations based on a number of ideas, including separation

from the set of rank-1 psd matrices, and, in particular, the method of approximate

representation of continuous variables as weighted sums of binary variables. We

will discuss theory and computational practice. Joint work (Gonzalo Munoz,

Chen Chen and Daniel Bienstock).

2 - Online First-order Framework For Robust Convex Optimization

Fatma Kilinc-Karzan, Carnegie Mellon University,

fkilinc@andrew.cmu.edu

, Nam Ho-Nguyen

We present a flexible iterative framework to approximately solve robust convex

optimization problems. Our results are based on weighted regret online convex

optimization and online saddle point problems. A key distinguishing feature of

our approach from prior literature is that it requires access to only cheap first-

order oracles for each constraint individually and does simple online updates in

each iteration while maintaining the same convergence rate. For strongly convex

functions, we also establish a new improved iteration complexity. As a result, our

approach becomes much more scalable and hence preferable in large-scale

applications from machine learning and statistics domains.

3 - New And Old Results On Polynomial Optimization

Daniel Bienstock, Columbia University,

dano@columbia.edu

We present ongoing work on solving polynomial optimization problems using

linear and convex relaxations based on a number of ideas, including separation

from the set of rank-1 psd matrices, and, in particular, the method of approximate

representation of continuous variables as weighted sums of binary variables. We

will discuss theory and computational practice, and attempt to relate our work to

earlier results by Renegar and Barvinok. Joint work (Gonzalo Munoz, Chen Chen

and Daniel Bienstock).

SC10