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Ants and ants based routing

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  • 1. ANTS AND ANTS BASEDROUTING Varun Chopra,ECE, Apeejay College of EngineeringE-mail: [email protected]

2. ABSTRACT Ad-hoc wireless sensor networks - activeresearch topic. Sensor networks characteristics are Embedded routers, dynamic networks, resource-constrained nodes, and unreliable and asymmetric links. Ant routing has shown good performance forcommunication networks. 3. ABSTRACT A mobile ad-hoc network (MANET) is acollection of mobile nodes which communicateover radio. Advantages No existing infrastructure required thereforesuitable for temporary communication links. Disadvantages Communication is difficult to organize due tofrequent topology changes 4. ABSTRACT British Telecom aware of the necessity to modernizeand improve phone service have reduced hardwareused by 100 times while increasing network capacityone hundredfold. They still need a smarter way. Who are they going to call? Ants. Thats right. Ants. British Telecom came to conclusion that ants handlesuch problems better than humans. A disrupted ant colony appears to have an amazingcapacity to re-align itself and get back to the normalroutine almost immediately. 5. COST EFFECTIVE What do those ants know that we dont? It is estimated that the cost of overhauling itsphone network the traditional way rewriting software, replacing switches, swapping copper wires with higher-capacity optical fiber It could take $46 billion. Spending $4 billion ayear, it would take more than a decade to finishthe job. And by then, it would be out of date. 6. SWARM INTELLIGENCE Ant algorithms are a class of swarm intelligence. Ant algorithms try to map the solution capabilityof ant colonies to mathematical and engineeringproblems. Ants display collectively intelligent behaviourwhen foraging for food or fighting off predators. Each ant in the colony acts in a rather simple way,but together they end up doing something clever,like discovering the shortest path between theirant hill and a food source. 7. DID YOU KNOW ? 8,800 known Ant species (Wilson) Combined weight more than the combinedweight of all humans Can carry up to 20 times their body weight Work in teams to lift heavy objects Brains largest amongst insects Same processing power as an Apple Mac II 8. DID YOU KNOW ? Ants brain 250,000 cells (Human brain 10billion cells) Average size one-millionth human size Send their senior citizens to war (Humanssend their young!) Edward Wilson Capable of finding shortest path to food 9. HOW ANTS FIND FOODPHEROMONES Many species of ants communicate with theirnest-mates using chemical scents known aspheromones. Pheromones can be used in many ways by antsand other animals, but we are most interested inhow ants use pheromones to direct each otherthrough their environment. This task is closely related to the problem ofdirecting the flow of information through anetwork 10. HOW ANTS FIND FOOD Consider a colony of ants that is searching for food. Casual observation reveal that ants often walk in astraight line between their anthill and the food source. The concept of an "army" of ants marching has been apopular culture, and most people have seen thisparticular behaviour first-hand. Marching in a straight line, which is usually the shortestroute, seems like an obvious solution to the problem ofefficient food transportation, and we might pass it offas uninteresting. 11. HOW ANTS FIND FOOD Suppose that an ant colony starts out with noinformation about the location food in theenvironment. The human strategy in this case would be to send out a"search party" to comb the surrounding area - thescouts who find food can bring some back to thehome-base and inform the others about where thefood is. Ants do search for food by walking randomly, which issimilar to the human "combing" approach, but twoissues prevent ants from implementing a human-stylesearch party directly. 12. HOW ANTS FIND FOOD First, how can an ant scout, upon discoveringfood, find its way back to the nest? Second, even if a scout makes it back to thenest, how can it inform the other ants aboutthe foods location? The answers lie in a clever use of pheromones. 13. FINDING HOME PROBLEM To solve the "finding home" problem, each antleaves a trail of pheromone as it looks forfood. In the following example pictures, thepheromone trail left by each wandering ant isshown in transparent red. 14. TELLING OTHERS PROBLEM When an ant finds food, it can follow its ownpheromone trail back to the nest. This is similar to leaving a trail of breadcrumbs through the woods to find your wayback home. On the way back to the nest, the ant solvesthe "telling others" problem by laying downmore pheromone, creating a trail with an evenstronger scent. 15. TELLING OTHERS PROBLEM In the following picture, ant A reaches thefood first and then follows its own trail back tothe nest, while the other three ants keepwandering. 16. ROUTING WISDOM FROM ANTS When other ants run into a trail ofpheromone, they give up their own searchand start following the trail. In the following picture, ant D discovers thedouble-strength trail left by ant A and starts tofollow it. 17. ROUTING WISDOM FROM ANTS Ant C encounters the single-strength trail leftby D and follows that trail, which willeventually lead to As trail as well. Ant B eventually discovers its own route to thefood source that is completely disconnectedfrom the routed used by A. 18. ROUTING WISDOM FROM ANTS If a pheromone trail leads an ant back to thenest with empty jaws, it turns around andfollows the trail in the opposite direction. Once an ant reaches the food, it grabs a pieceand turns around, following the same trailback to the nest. On the way back, an ant reinforces the trail bylaying down more pheromone. 19. ROUTING WISDOM FROM ANTS In the following picture, ant C joins As trailbut follows it the wrong direction, reachingthe nest empty-jawed. Ant B follows its own trail back to the nest. Itnever comes in contact with the more directtrail that the other ants are using. 20. ROUTING WISDOM FROM ANTS A and D carry food back to the nest along theestablished route. Once they reach the food,they grab a piece and turn around, followingthe same trail back to the nest. On the way back, they reinforce the trail bylaying down more pheromone. 21. SMART ANTS We have explained how ants find food in thefirst place, but how do they find the shortestroute to the food? One more detail helps to answer thisquestion: ants prefer to follow the trails withthe strongest pheromone scent. Shorter route between the nest and the foodare completed faster by each ant that takesthem. 22. SMART ANTS For example, if ant X is travelling along a 10-meter path to the food repeatedly, and ant Y istravelling along a different 20-meter pathrepeatedly, ant X will make twice as many trips inan hour as ant Y. Thus, ant X will lay twice as much pheromone onits trail as ant Y. Given the choice, ants will prefer the strongly-scented 10-meter path over the more weakly-scented 20-meter path. 23. SMART ANTS When B deposits food at the nest and sets outfor another trip, it discovers the strongly-scented path used by the other ants andabandons its own path. At this point, all four ants are using the pathdiscovered by ant A to carry food between thesource and the nest. 24. ANT-BASED ROUTING The ant approach to route-finding is quite differentfrom the way humans navigate their environment. We would visually study the environment as a wholeand try to "plan" the best route ahead of time. Of course, the ant method has advantages over our"high level" approach. For example, the ant method works fine in completedarkness. When it comes to navigating without visual cues,humans are comparatively helpless. 25. ANT-BASED ROUTING The ant method into simple rules :CONDITIONACTIONNot carrying food not on walk randomly lay pheromonepheromone trailNot carrying food on follow pheromone trail lay morepheromone trailpheromoneReach home without food turn around follow trail inon pheromone trailopposite direction 26. Reach food pick up food pick up food turn around follow trail in opposite directionCarrying foodfollow trail lay more pheromoneReach home with food deposit food turn around follow trail in opposite direction 27. CONCLUSION MANET uses algorithms that allowconstructing and maintaining wirelesscommunications network for a large numberof mobile hosts in an environment subject tosubstantial and unpredictable changes. So we can conclude that Ants based routingwould just be the solution.