Greedy algorithms best for multiple targets

Dec 09, 2010

What algorithms should an air defense system work with? Particle swarm algorithms if there are ten targets to be hit. If there are more than ten targets, greedy algorithms work best. These findings are presented by researcher Fredrik Johansson at the Informatics Research Centre, University of Skovde, in Sweden.

So-called TEWA systems (Threat Evaluation & Weapon Allocation) are used to protect strategic targets from enemy attacks, such as an airfield that needs to be protected from incoming missiles.

The systems discover threats, evaluates the threats, and aims the defender's weapons system to be able to knock out the threat. The final decision to fire is then made by an operator.

Researcher Fredrik Johansson at the Informatics Research Centre, University of Skövde, in Sweden, recently defended his doctoral thesis on algorithms for TEWA systems.

"In the existing research literature there are proposals regarding what algorithms may be appropriate to use in TEWA systems. I have developed methods to test which algorithms work best in practice," explains Fredrik Johansson.

Fredrik Johansson's study shows that what determines the choice of algorithm is the number of weapons in the TEWA system and the number of targets the system has to deal with.

"So-called particle swarm algorithms are effective if it's a matter of up to about ten targets and ten weapons. If the TEWA system needs to keep track of more targets and weapons, we should use what are called greedy algorithms instead," says Fredrik Johansson.

A greedy algorithm – simply put – is fast but not perfect. The algorithm works under broad guidelines and does not test all the alternatives necessary to obtain an optimal solution. The fact that it doesn't need to test certain solutions makes it a rapid algorithm, a property that is crucial in a TEWA system.

"You can't let it take many seconds between the system discovering a threat and the operator deciding whether or not to fire," says Fredrik Johansson.

In previous studies TEWA systems have nearly always been treated as two parts: threat evaluation and weapon allocation separately. Fredrik Johansson's study is one of the first to see the system as a unit. But to claim that you are the first to study something may be difficult when it comes to TEWA systems.

"Those conducting research in this field don't always know what knowledge there is beneath the surface. There's probably some research about TEWA systems that is secret and not available to us ordinary researchers," concludes Fredrik Johansson.

Explore further: Researchers use Twitter to predict crime

add to favorites email to friend print save as pdf

Related Stories

Secure radio signal for central locking

Feb 01, 2010

(PhysOrg.com) -- Remote central locking is among the most convenient aspects of modern motoring. Transmission of the radio signal that activates the system is not particularly secure, however. A new encryption ...

A new way to help computers recognize patterns

Jan 25, 2006

Researchers at Ohio State University have found a way to boost the development of pattern recognition software by taking a different approach from that used by most experts in the field. This work may impact research in areas ...

A new method for developing safer drugs

May 10, 2010

Amodiaquine was introduced as an antimalarial drug, but was withdrawn when serious adverse effects were observed. Scientists at the University of Gothenburg, Sweden, have now developed a method that can be used to develop ...

Recommended for you

User comments : 0

More news stories

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.

Low tolerance for pain? The reason may be in your genes

Researchers may have identified key genes linked to why some people have a higher tolerance for pain than others, according to a study released today that will be presented at the American Academy of Neurology's 66th Annual ...

How to keep your fitness goals on track

(HealthDay)—The New Year's resolutions many made to get fit have stalled by now. And one expert thinks that's because many people set their goals too high.

Less-schooled whites lose longevity, study finds

Barbara Gentry slowly shifts her heavy frame out of a chair and uses a walker to move the dozen feet to a chair not far from the pool table at the Buford Senior Center. Her hair is white and a cough sometimes interrupts her ...