Congestion in Facilities Location and Layout

National Science Foundation

Congestion in Facilities Location and Layout: Deterministic and Stochastic Models

Papers and Talks


The project aims at developing a common theory base to model movement and resultant congestion in the context of facilities location and facilities layout. The motivation stems from the fact that the two bodies of literature in facility layout and facility location have generally evolved separately — facility layout deals with the simultaneous placement of multiple finite area entities such as departments or cells, while facility location deals with the placement of infinitesimal-sized facilities, perhaps in the presence of finite-sized barriers to travel or forbidden regions for new location. The objective is to produce a superior class of models (over the traditional centroid distance and unit cost measures) that are expected to provide better performance in real-life applications via the explicit consideration of slow-downs, congestion, flow capacity, and accurate distances.

The research work has three main tasks.

The first one is called the Planar Facility Location Problem with Generalized Congested Regions that advances and unifies existing restricted facility location literature by common modeling of three types of closed and bounded regions in the plane: Barriers, through which neither travel nor facility location is permitted, Forbidden Regions in which facility location is prohibited, and Congested Regions in which facility location is prohibited but through which travel is permitted at an additional cost per unit distance (denoted by a congestion factor). In the dynamic/stochastic version of this problem the congestion factor might change with time of day (to represent rush hour traffic) or be a random variable.

The second research task is called the Connection Location Problem. We use the term “connection” in a generic sense to define a connected part of a manufacturing facility or an urban flow network that links different sets of departments/cells or facilities. The deterministic version of this task concerns the specific problem of variable capacity sizing and selection/location of connections within a facility layout/location context in order to minimize the sum of the fixed connection installation costs and proportional material movement costs in the material handing system (MHS). The stochastic version of this task concerns selection/location and the service rate of the connections (and to assign the flows) so as to minimize the sum of the fixed connection installation costs, the queueing delay cost, and the material movement cost in the MHS, that take into consideration the congestion effects.

The third task is software development to embody the theoretical results of the study as well as development of Educational material.


Intellectual Merits:

The first task would study the plant layout problem in which distance measures vary in different sections of the plant, and also consider location problems in a modeling framework that simultaneously allows for barriers, forbidden regions and congested regions. The second task would allow for modeling of aisle capacities and placement and add significantly to the limited literature available in this area. This task will introduce and research a new concept in location theory relative to connections. The third task would create a software that would be the first in the plant layout area to allow for detailed specificity on distance measurement, and unique from a location perspective to allow simultaneous consideration of generalized congested regions. It would also address connection sizing/location.

Broader Impacts:
Training of two doctoral and two masters students and generation of about five articles in premier scientific journals and also associated teaching materials. Involvement of students from underrepresented groups to participate in this project (through SUNY Alliance for Minority Participation program). Undergraduate student participation to be included via an REU supplement.
On the application front, the project will provide practitioners with a readily available tool (software) for location/layout design. The broad dissemination of our work is to be achieved with research publications, and embodying those concepts in instructional material and software for outreach to participants beyond the home institution’s boundary.


Dr. Rakesh Nagi
117 Transportation Building
104 S. Mathews
Urbana Illinois 61801
Phone: (217) 244-3848
Fax: (217) 244-5705

Dr. Rajan Batta, Professor
Department of Industrial Engineering
State University of New York at Buffalo
420 Bell Hall
Buffalo, NY 14260-2050
Telephone: (716) 645-2357
FAX: (716) 645-3302

Graduate Students:

Undergraduate Students:

Papers and Talks


Journal Papers accepted:

Journal Papers submitted: