Design and protection strategies for critical infrastructure systems and supply chains

Funding Agency: EPSRC

Date: 2007 – 2010

Project team:

  • Dr. Maria Paola Scaparra (Kent Business School)
  • Professor Richard Church (University of California)
  • Professor Mark Daskin (Northwestern University)
  • Dr Lawrence Snyder (Lehigh University)
  • Federico Liberatore (PhD student)
  • Chaya Losada (PhD student)

Recent world events have highlighted the vulnerability of our service and supply systems to sudden service disruptions due to deliberate sabotage and large natural disasters. As a consequence, the issues of systems vulnerability, security investment and design of resilient transportation and distribution networks have received considerable attention over the past few years.

This research program focused on the development of mathematical models that can be used by researchers and industrial managers to better understand the most appropriate means of increasing infrastructure security, robustness and reliability in the face of man-made and environmental threats.

About the Project

Infrastructure systems and supply chains are at the basis of societal functions and reach into every aspect of modern life. Examples of these vital systems include goods and service distribution networks, emergency services, financial services, transportation and telecommunication networks, electrical power grids and water supply systems among others.
Unfortunately, recent world events have demonstrated that even the strongest supply chains or infrastructure systems can be extremely vulnerable to unforeseen events, such as terrorist attacks, hurricanes, earthquakes and so on.

Other less catastrophic but more frequent incidents, such as plant fires, industrial accidents, labour strikes and power outages, can also have costly and, sometimes, harmful implications, especially if the incapacitated or destroyed supply line provides essential services or goods (e.g., hospitals, drugs, vaccines).

In view of all these risks and hazards, there has been a heightened awareness and concern over the past few years for increasing the security and reliability of infrastructure and supply systems that may be subject to potential external disruptions.

Planning against possible disruptive acts of nature or terrorism is an enormous financial and logistical challenge, especially if one considers the scale and complexity of today’s logistic systems, the increasing interdependence among numerous system elements, the variety of threats and hazards, and the prohibitive costs involved in securing large numbers of system components.

Since it is generally impossible to secure all assets, it is important to devise systematic approaches for identifying critical elements, optimize the protection of key system components and even build new systems which are inherently robust. Optimization techniques can play a significant role in this respect.

Over the last few years, a few optimization models have been developed for identifying supply chain configurations that are both reliable with respect to disruptions and economically cost-effective in terms of infrastructure investment (design models). Additionally, new models have been proposed recently which can be used to improve the reliability of infrastructure systems that are already in place and for which a complete reconfiguration would be too costly (protection models).

The overall objective of this project is to develop a suite of new optimization models in both of these reliability-related research areas. In particular, new modelling approaches will be developed to overcome some of the overly simplified assumptions which characterize existing models, to capture additional complex issues arising in systems reliability planning, and to reflect the diversity of possible application settings.

As an example, future modelling efforts should aim at incorporating various combinations of the following issues:

  • different operational protocols of the systems (cost-based vs. standards-based supply models);
  • different types of hazards (expected models for natural disasters vs. worst-case models for premeditated attacks);
  • different underlying models (facility location, network, multi-echelon supply models);
  • stochastic aspects such as random numbers of possible losses and component-specific failure probabilities;
  • different degrees of facility protection (protected components may be completely immune to attacks and failures, have a lower probability of being disrupted, or preserve part of their operational capabilities depending on the level of protection investment);
  • multiple objectives (operational costs, lost-sales cost, system efficiency, coverage, risk level).

Both exact and heuristic techniques will also be developed to solve the newly proposed models.


M.P. Scaparra, R.L. Church. 2008. A bilevel mixed integer program for critical infrastructure protection planning. Computers and Operations Research, 35:1905-1923.

M.P. Scaparra, R.L. Church. 2008. An exact modeling approach for the interdiction median problem with fortification. European Journal of Operational Research, 189:76-92.

C. Losada, M.P. Scaparra, R.L. Church. 2010. On a bi-level formulation to protect uncapacitated p-median systems with facility recovery time and frequent disruptions. Electronic Notes in Discrete Mathematics, 36:591-598.

M.P. Scaparra, P. Cappanera. 2011. Optimal allocation of protective resources in shortest path networks. Transportation Science, 45:64-80.

F. Liberatore, M.P. Scaparra, M. Daskin. 2011. Analysis of facility protection strategies against an uncertain number of attacks: The Stochastic R-Interdiction Median Problem with Fortification. Computers and Operations Research, 38:357-366.

F. Liberatore, M.P. Scaparra. 2011. Optimizing protection strategies for supply chains: Comparing classic decision making criteria in an uncertain environment. Annals of the Association of American Geographers, 101(5):1-17.

F. Liberatore, M.P.Scaparra, M. Daskin. 2012. Hedging against disruptions with ripple effects in location analysis. Omega, 40:21-30.

C. Losada, M.P. Scaparra, and J.R. O’Hanley. 2012. Optimizing system resilience: A facility protection model with recovery times. European Journal of Operational Research, 217(3):519-530.

M.P. Scaparra, R.L. Church. 2012. Protecting supply systems to mitigate potential disaster: a model to fortify capacitated facilities. International Regional Science Review, 35: 188-210.

F. Liberatore, B. Vitoriano, M.T. Ortuno, G. Tirado, M.P. Scaparra. 2012. A hierarchical compromise model for the joint optimization of recovery operations and distribution of emergency goods in humanitarian logistics. Computers and Operations Research. In press. Published online April 2012.

C. Losada, M.P. Scaparra, R. Church, M. Daskin. 2012. The stochastic interdiction median problem with disruption intensity levels. Annals of Operations Research,201: 345-365.

J. R. O’Hanley, M.P. Scaparra, S. Garcia. 2013. Probability Chains: A general linearization technique for modelling reliability in facility location and related problems. European Journal of Operational Research, 230(1): 63-75.



CO2012, Oxford University, UK, September 2012
Solving location problems with facilities prone to disruption: An efficient linearization technique, with O’Hanley and Garcia.

OR 52, Royal Holloway University of London, UK, September 2010
Identifying efficient investments in protection and security measures: Recent advances in protection modelling.

EURO 2010, Lisbon, Portugal, July 2010
An integer programming formulation for the non-uniform p-median problem with unreliable facilities

EWGLA Meeting 2010, Naples, Italy, April 2010
Disaster mitigation strategies against disruptions with ripple effects, with Liberatore and Daskin.

AIRO 2009, Siena, Italy, September 2009
Improving supply system’s reliability against random disruptions: Strategic protection investments.

EURO 2009, Bonn, Germany, July 2009
Hardening facilities against random disruptions.

AIRO 2008, Ischia, Italy, September 2008.
Optimizing security investments in shortest path networks, with P. Cappanera.

ISOLDE XI, Santa Barbara, California, USA, June 2008.
Hardening facilities against random numbers of losses, with F. Liberatore and M. Daskin.

ISOLDE XI, Santa Barbara, California, USA, June 2008.
A multi-level modeling approach for the capacitated p-median interdiction problem with fortification, with R.L. Church.

CO 2008, Warwick, England, March 2008.
A multi-level optimization model for improving the robustness of capacitated supply systems.

Invited talks

  • Koҫ University, Istanbul, Turkey, May 2013
    Optimizing facility protection strategies in service systems: State of the art and future directions
  • Università federico II, Naples, Italy, April 2010
    Identifying critical components and weaknesses in service systems.
    Enhancing the reliability of infrastructure systems: A survey of protection planning models.
  • SIDT 2009 International Conference, Milan, Italy, June 2009
    Protection strategies for critical infrastructure systems and supply chains.
  • FIMA International Conference, Gressoney, Italy, January 2009
    Protection strategies for critical infrastructure systems and supply chains.
    Plenary Talk

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