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INFORMS Nashville – 2016

367

4 - Optimization Of Cascading Processes In Multiscale Networks

With Stochastic Interactions

Oleg A Prokopyev, University of Pittsburgh, 1037 Benedum Hall,

Pittsburgh, PA, 15261, United States,

droleg@pitt.edu,

Juan Borrero, Pavlo Krokhmal

We study the problem of optimal cascade propagation in a network, where the

cascade’s spread depends on a vector of given attributes. Given there are costs

associated with changing the attributes’ values, a decision-maker desires to

minimize the time until all network nodes receive influence, subject to a budget

constraint. To this end, we propose a stochastic optimization model based on

Markov chains. Under simple assumptions, we derive analytical solutions for the

optimal budget allocation in terms of a minimum spanning arborescence on an

auxiliary graph. These results establish that optimal solutions have a hierarchical

structure, and show that they can be found in polynomial time.

WA12

104B-MCC

Optimization in Cyber Defense

Sponsored: Optimization, Integer and Discrete Optimization

Sponsored Session

Chair: Les Servi, MITRE, 202 Burlington Road, Bedford, MA, 01730,

United States,

lservi@mitre.org

Co-Chair: Doug Altner, MITRE Corporation, 7525 Colshire Drive,

McLean, VA, 22102, United States,

daltner@mitre.org

1 - A Supply Chain Network Game Theory Model Of Cybersecurity

Investments With Nonlinear Budget Constraints

Shukla Shivani, University of Massachusetts, Amherst, MA,

United States,

sshukla@som.umass.edu,

Anna B Nagurney,

Patrizia Daniele

In our paper, we develop a supply chain network game theory model consisting

of retailers that compete noncooperatively to maximize their expected profits and

reduce network vulnerability by determining their optimal product transactions

as well as cybersecurity investments subject to nonlinear budget constraints that

include the cybersecurity investment cost functions.

2 - Optimal Scheduling Of Cybersecurity Analysts For

Minimizing Risk

Rajesh Ganesan, George Mason University, Fairfax, VA, 22030-

4422, United States,

ashah20@masonlive.gmu.edu

, Ankit Shah,

Sushil Jajodia, Hasan Cam

The talk presents a generalized optimization model for scheduling cybersecurity

analysts to minimize risk (a.k.a maximize significant alert coverage by analysts)

and maintain risk under a pre-determined upper bound. The paper tests the

optimization model and its scalability on a set of given sensors with varying

analyst experiences, alert generation rates, system constraints, and system

requirements.

3 - Dynamic Scheduling Of Cybersecurity Analysts For Minimizing

Risk Using Reinforcement Learning

Rajesh Ganesan, George Mason University, Fairfax, VA, 22030-

4422, United States,

ashah20@masonlive.gmu.edu

, Ankit Shah,

Sushil Jajodia, Hasan Cam

The talk presents a reinforcement learning-based stochastic dynamic

programming optimization model that incorporates the estimates of future alert

rates and responds by dynamically scheduling on-call cybersecurity analysts to

minimize risk (a.k.a maximize significant alert coverage by analysts) and maintain

the risk under a pre-determined upper bound.

4 - A Two-stage Stochastic Shift Scheduling Model For Cybersecurity

Workforce Optimization With On Call Options

Doug Altner, MITRE Corporation, McLean, VA, United States,

daltner@mitre.org

, Les Servi

This talk proposes a two-stage stochastic program for optimizing staffing and shift

scheduling decisions at a 24/7 cybersecurity operations center with three shifts

per day, several staffing and scheduling constraints, uncertain workloads and on

call staffing options. We then show how near optimal solutions can be obtained in

a few minutes without a full branch-and-price implementation.

WA13

104C-MCC

Recent Developments in Optimization Software

Sponsored: Optimization, Computational Optimization and Software

Sponsored Session

Chair: Hans Mittelmann, Arizona State University, Box 871804,

Tempe, AZ, 85287-1804, United States,

mittelmann@asu.edu

1 - Selected Benchmark Results

Hans Mittelmann, Arizona State University,

mittelmann@asu.edu

We will present results from selected benchmarks we are maintaining in both

continuous and discrete optimization by both commercial and open source

software.

2 - Recent Advances In The New Mosek 8

Andrea Cassioli, MOSEK,

andrea.cassioli@mosek.com

Erving

Anderson

In this talk we present the new features and improvements in the new MOSEK 8

solver. Improved presolving, automatic dualization for conic quadratic problems

and other new developments in the core routines has lead to a significant

improvements of the solver performance both in terms of speed and accuracy.

Computational results will be presented and discussed.

3 - Recent Advances In The SCIP Optimization Suite

Gregor Hendel, Zuse Institute Berlin, Takustrasse 7, Berlin, 14195,

Germany,

hendel@zib.de

The general-purpose branch-and-cut solver SCIP is one of the fastest

noncommercial software tools for solving mixed integer linear optimization

problems. In this talk, we will give an overview of algorithmic advances in the

upcoming release with a special focus on new and extended primal heuristics of

SCIP.

4 - UG[PIPS-SBB, MPI]: A Massively Parallel Branch-and-bound

Solver For Stochastic Mixed-integer Programs

Yuji Shinano, Zuse Institute Berlin,

shinano@zib.de

, Lluis-Miquel

Munguia, Geoffrey Malcolm Oxberry, Deepak Rajan

PIPS-SBB is a LP-based branch-and-bound solver using a distributed-memory

simplex algorithm that leverages the structure of stochastic mixed-integer

programs (MIPs). However, it does not parallelize its branch-and-bound tree

search. The Ubiquity Generator (UG) is a general framework for the external

parallelization of mixed-integer programming solvers. It has been used to develop

ParaSCIP, a massively parallel version of the academic constraint integer

programming solver SCIP. In this talk, we will introduce a parallel solver ug[PIPS-

SBB, MPI] in which PIPS-SBB’s branch-and-bound tree search is parallelized on

top of the parallel solution of the LP relaxations.

WA14

104D-MCC

Inventory Management

Contributed Session

Chair: Reha Uzsoy, North Carolina State University, Dept. of Industrial

& Systems Engg, 300 Daniels Hall Camps Box 7906, Raleigh, NC,

27695-7906, United States,

ruzsoy@ncsu.edu

1 - Inventory Control Policy For A Periodic Review System

With Expediting

Yi Tao, Assistant Professor, Guangdong University of Technology,

161 Yinglong Road, Tianhe District, Guang Zhou, 510520, China,

kenjimore@gmail.com

, Loo Hay Lee, Ek Peng Chew, Gang Sun,

Charles Vincent

We study a periodic review inventory system where two modes, regular and fast

mode, are available to obtain replenishment. A firm can choose fast mode with

shorter lead time at a higher cost when necessary. A two-replenishment-mode

model, with random expediting points is established and an ordering policy (S,e)

which replenishes the inventory to S in every cycle and expedites part of the

order using fast mode when the inventory drops below e, is proposed. A

simulation optimization based heuristic which uses infinitesimal perturbation

analysis (IPA) method and gradient search algorithm is employed to find the best

(S,e). Numerical experiments have shown our new policy outperforms existing

policies.

WA14