Abstract:

The theme of this special issue of IJPE, viz., System Survivability and Defence against External Impacts is very topical. At the beginning of this Century, it could not have been even imagined that a commercial airliner loaded with 200,000 pounds of jet fuel could make a weapon of mass destruction resulting in the loss of valuable assets, national pride and in deaths of 2749 innocent civilians. In the Post 9/11 era, it has become very difficult for nations to protect their public assets and infrastructure due to unpredictability of the choice of place and time of attack by the terrorists. The predictability becomes even more difficult due the enormity of the systems being defended.

For example, stretched across 64,000 kilometers, connecting 8,000 stations by 12,000 trains running everyday, India has the second largest rail network in world. Since 1997, there have been number of instances of direct assaults, bombing and sabotages leading to derailments. It is almost impossible to predict when and where such attacks could take place on this network. It is also costly to devise a strategy to protect such a large infrastructure. Likewise, defence of other important establishments such as space, scientific, military, nuclear, energy, communications or civic structures may call for massive investments to devise any effective strategy to protect them. Survivability of important assets of such kinds cannot be treated as a system performance issue alone. Because a defender must allocate resources to a set of selected locations without the precise knowledge of attacker's preference for the time and location of attack, a defensive strategy against the perceived attack scenarios has to be evolved using game theory, operations research and statistical and probabilistic models.

An attacker could also gain access to weapons of mass destruction including nuclear devices, germs and poisonous gasses or use even computer viruses. The series of recent anthrax attacks has reinforced the importance of allocations of resources for bio-surveillance systems and for a timely detection of the extent of dangers from the spread of epidemics. An attack involving the nerve agent sarin in Tokyo subway in March 1995 demonstrated not only the extensive social disruption a chemical attack can cause but also the complexities involved in mounting an effective response. Therefore, defending public utility systems is gradually becoming an uphill task and needs strategic allocations to defend such vital systems.

Defence of national resources and infrastructure against a terrorist attack is a very complex problem of importance to all nations of the world and requires a careful and judicious consideration.? We have attempted to present some of the aspects of this problem in this issue.

This special issue comprises 7 papers from authors from various disciplines on some of the problems related to the theme. I would like to thank all authors who have contributed their research papers to this special issue.? Without the untiring effort of the Guest Editor, Dr. Gregory Levitin of The Israel Electric Corporation Ltd., Haifa in selecting the papers and getting them reviewed and revised, the present special issue would not have been possible. My special thanks are also due to several referees, who unhesitatingly helped in reviewing the submitted papers and bringing them to the present form.