2016 INFORMS Annual Meeting Program

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INFORMS Nashville – 2016
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4 - Changes In Community State Types Reflect Major Shifts In The
Human Microbiome
Paul Brooks, Virginia Commonwealth Univ,
The human microbiome consists of the micro-organisms that reside in various
body habitats. We present a re-analysis of five sequencing-based surveys of the
vaginal microbiome with repeated measures. Our goal is to understand the
expected persistence in a state, the rate of state changes, our ability to predict an
upcoming change, and predictors of upcoming changes. Our results provide
insight into microbiome dynamics.
TB03
101C-MCC
Marketing Strategies of Entertainment Products
Invited: Entertainment Analytics
Invited Session
Chair: Yong Liu, University of Arizona, 1130 E Helen Street,
Tucson, AZ, 85721, United States,
1 - Pre-launch Analysis Of Competitive Dynamics
Natasha Zhang, University of Virginia, ,
Fang Wu, Vithala R Rao
The market structure literature has focused on mature products and post-launch
competition. Yet many industries such as entertainment see frequent product
introductions with short lifecycles; and need to identify dynamic market structure
pre-launch to guide marketing mix decisions largely made pre-launch. However,
such identification is almost impossible because of lack of sales data and dynamic
competition resulting from entries, exits, and changes in preannounced release
timing. The authors thus propose a dynamic market structure model to capture
the evolution of competitive sets and brand positioning, calibrated on a film
prediction market.
2 - The Choice And Effects Of Movie Previews In
Video-on-Demand Services
Yong Liu, University of Arizona, Tucson, AZ, United States,
, Zhen Chen, Madhu Viswanathan,
Hongtao Pan, Pei Huang
A key strategy that the Video-on-demand (VOD) providers use to help consumers
choose among numerous programs is the provision of program reviews. In this
paper we investigate when consumers choose to watch previews and how
preview watching may influence movie choice. Our research context are the on-
demand movies in the Internet Protocol TV (IPTV) systems from a large Chinese
VOD service provider. We find that the movie attributes, household
characteristics, and time of the week significantly affect consumer choice for
previews. At the same time, the ratio of preview watching time to the length of
the preview program has a significant impact on the subsequent movie choice.
TB04
101D-MCC
Developing Country Electricity Systems
Sponsored: Energy, Natural Res & the Environment, Energy I
Electricity
Sponsored Session
Chair: Valerie Thomas, Georgia Tech, 765 Ferst Drive, Atlanta, GA,
30332, United States,
1 - Electricity Development In Africa - A Multi-objective Optimization
Approach
Amelia Musselman, Georgia Institute of Technology, Atlanta, GA,
United States, , Dima Nazzal,
Valerie Thomas
Many people across Africa are without sufficient access to electricity. The
unavailability and unreliability of energy resources in Africa contribute to
developmental challenges in many areas including business, education, and
healthcare. We develop a mixed integer optimization model for power generation
and transmission system expansion planning in Africa. In addition to solving the
least cost optimization, we consider optimal use of a fixed electrification budget
when demand cannot fully be met. We test our model on the Democratic
Republic of Congo, Uganda, Tanzania, Rwanda, and Burundi.
2 - Can Developing Countries Leapfrog The Centralized
Electrification Paradigm?
Todd Levin, Argonne National Laboratory,
Due to the decreasing costs of decentralized technologies, centralized power
systems are no longer a necessary condition of universal electricity access.
Developing countries with less developed infrastructures may be able to adopt
these new technologies more quickly. We determine the electricity consumption
levels at which the costs of centralized and decentralized electrification are
equivalent in three African regions. We then calculate capital costs necessary for
distributed technologies to cost-effectively provide each of five tiers of energy
access, as defined by the UN SE4All Framework.
3 - Analysis of a Wind-Hydro Storage System in Kenya
Maureen Murage, Cornell University, Ithaca, NY, Contact:
Kenya has set a target of increasing the wind power capacity from 1% to nearly
15% of total generation capacity. The Lake Turkana Wind Power (LTWP) wind
farm will be the largest installation, contributing to half of this total. In this
presentation, we will discuss the reliability impact of LTWP project on the Kenyan
Power system. The results indicate that the addition of wind power into the
system only marginally improves the reliability of the power system, though
other implementation strategies may improve this outcome.
TB05
101E-MCC
Optimal Power Flow
Sponsored: Energy, Natural Res & the Environment,
Energy I Electricity
Sponsored Session
Chair: Andy Sun, Georgia Institute of Technology, Atlanta, GA,
United States,
1 - Visualizing The Feasible Spaces Of Optimal Power Flow Problems
And Their Convex Relaxations
Daniel K Molzahn, Argonne National Laboratory,
Optimal power flow (OPF) problems can have non-convex feasible spaces.
Visualizing these feasible spaces can aid in understanding these non-convexities.
Work towards developing such visualizations uses the Numerical Polynomial
Homotopy Continuation (NPHC) algorithm, which is guaranteed to find all power
flow solutions. By discretizing the inequality constraints, repeated power flow
solutions using NPHC enables calculation of the feasible spaces for small OPF
problems. This presentation illustrates the feasible spaces of several challenging
OPF problems and various convex relaxations.
2 - Global Optimization Techniques For The Optimal
Power Flow Problem
Burak Kocuk, Carnegie Mellon University, Pittsburgh, PA, United
States, , Santanu S. Dey, Andy Sun
In this study, we aim to solve the Optimal Power Flow problem using global
optimization techniques. Our analysis starts with an equivalent SDP formulation
of the problem with additional nonconvex minor constraints. We propose several
convexification approaches to deal with these nonconvexities via cutting planes
and envelopes. We make efficient use of bound tightening to stregthen the
convex relaxations. We also develop an SOCP-based spatial branch-and-cut
algorithm. Our approach is successful in proving small optimality gaps for
challenging power systems instances from the literature.
3 - Convex Cuts For Optimal Power Flow
Hassan Hijazi, Australian National University, Canberra,
Australia, , Carleton Coffrin,
Pascal Van Hentenryck
Global optimality and feasibility guarantees are highly desirable outcomes for
problems arising in application areas with critical infrastructures. These include
energy, transportation, telecommunication and cyber-security systems. A global
approach is necessary to prove that the underlying model is infeasible or that the
provided solution is optimal. Unfortunately, off-the-shelf global optimization tools
are unable to scale up to real-world size problems. This presentation will cover
recent results on the generation of valid convex cuts for nonconvex quadratically
constrained programs, focusing on key application problems such as the Optimal
Power Flow.
4 - Convexification Of The Power System State Estimation Problem
Yu Zhang, University of California, Berkeley, Berkeley, CA, United
States, , Ramtin Madani, Javad Lavaei
This presentation deals with the power flow (PF) and power system state
estimation (PSSE) problems. The PF problem is cast as an optimization problem
by adding a well-designed quadratic objective. It is shown that with a suitable set
of measurements and under mild angle conditions, the semidefinite programming
(SDP) relaxation can recover the true solution. Capitalizing on this result, a
penalized SDP using the weighted least absolute value data fitting cost is tailored
for the PSSE. The optimal SDP solution has a dominant rank-one component
formed by lifting the true state. An upper bound on the estimation error is also
derived, which depends on the noise power.
TB05