Se les invita a todos al seminario del próximo jueves 16 Marzo 2017

Lugar: Auditorio Raúl Quintero

PISIS Seminar Spring 2017 Semester

 

Title:  Optimal Commercial Districting:  Models, Relaxations, and Algorithms[1]

Speaker:  Roger Z. Ríos / Graduate Program in Systems Engineering / UANL

Abstract:  Territory design or districting is the problem of grouping small geographic areas called basic areas into larger geographic clusters called territories such that the latter fulfill relevant planning criteria. Moreover, spatial restrictions, such as compactness or contiguity, are often demanded. Districting problems are motivated by very different applications, such as political districting design of territories for waste collection, sales and service territory design, school districting.  In this talk a commercial territory design problem motivated by a real-world application from a bottled beverage distribution firm is presented.  The problem consists of finding a set of territories subject to contiguity, compactness, and multiple balance requirements with respect to each node activity measure (number of customers, product demand, and workload.)  After presenting a description of the problem and a discussion of its associated mixed-integer programming model, a proposed exact optimization scheme based on branch and bound and cut generation is described in detail.  The model is strengthened by the introduction of some valid inequalities that ensure a dominant class of the connectivity constraints is met.  Additionally, we introduce a new integer quadratic programming model for this problem.  The talk will include an empirical assessment of the trade-offs between the linear and quadratic models and a detailed evaluation of the proposed exact method and algorithmic strategies.

Biosketch:  Roger Rios is a Professor of Operations Research in the Graduate Program in Systems Engineering at Universidad Autonoma de Nuevo Leon, Mexico. He has held Visiting Scholar positions at the OR/IE Program, U. of Texas at Austin, USA; Department of Operations Research, Universitat Politecnica de Catalunya, Spain; Leeds School of Business, U. of Colorado; and High Performance Computing Center, U. of Houston.  He holds a PhD in OR/IE from the U. of Texas at Austin.  His research interests are mainly in designing and developing efficient solution methods to hard discrete optimization problems. He has addressed applied decision-making problems on districting, location, healthcare, forestry management, natural gas transportation systems, and scheduling. His research has been published in leading journals in the field reporting over 1700 citations in GoogleScholar. He is a member of the Editorial Board of Computers & Operations Research and Operations Research Perspectives.  He is a Level 2 Fellow of the Mexican System of Research Scientists and Member of the Mexican Academy of Sciences.  He is a former President and a founding member of the Mexican Society of Operations Research.  More about his work can be found at http://yalma.fime.uanl.mx/~roger/.