1. DATA RETRIEVAL IN ADHOC NETWORKS
By Aviraj Sinha CSE5343

2. Ad-Hoc: Definition Revisited
Definition: network based on personal connections for a specific task
Each computer becomes a client, server, and router.
Ad-hoc is a type of P2P network
Can store data that can be mined (decentralized retrieval)

3. P2P

4. History of P2P Napster Spotify DropBox BitTorrent
This Photo by Unknown Author is licensed under CC BY-SA
This Photo by Unknown Author is licensed under CC BY
This Photo by Unknown Author is licensed under CC BY-SA

5. Reason for Effectiveness
Pieces of file can be simultaneously received
The client that receives it can be used as a nodes
Extremely cheap, redundant scalability
Self-sufficient and efficient

6. Importance of Ad-hoc networks
Users only private network allows efficiency of hops
Capable of going off-grid (Legal implications)
Reliably redundant for police and military

7. Potential
VANET Cars will be self driven and will communicate with each other to prevent traffic jams and crashes
TETRA radio for police—much better solution to thrashing in central radio systems

8. VANET

9. More Potential
MANET- continuously self-configuring, physical infrastructure-less network
Ease of networking on PAN,
Far future use on multiple hierarchies of LAN and MAN

11. Set Backs Rapidly changing topology Network partitions and security
Higher error rates, collision interference, bandwidth constraints,
Power limitations

12. Data Retrieval Algorithm Characteristics
WANET routing algorithms are different from traditional routing algorithms.
Data retrieval requires huge amounts of data from decentralized storage.
Asynchronous not keeping the time because it is too big,
Fault tolerant-- the parts of data change while the algorithm is running

13. Searching Categories: Blind and Structured
Search is blind –each node does not have information to where data needed is located. Depth first search (DFS)
Or structured where the search is routed. Exact local algorithms

15. More Complex Methods– Intelligent Searching Mechanisms
Neighbor Profile
Relevancy Rankings
pSearch, a non-flooding system using Latent Semantic Indexing
Data overlays– using in depth local knowledge
Genetic algorithms (Machine Learning)

16. Indexing Strategies
Posting lists for carefully chosen indexing term combinations
Statistically bounded number of their top-ranked elements.
Local vs Global index
Gossiping--global inverted index which is partially constructed by each node propagated to the rest of the network

17. All information shared, simple routing
Purely Central
Can use Normal Routing Protocols
Requires More complex Algorithms

18. Hybrid technique Local indices contain the ”direction” to global index
Compound Routing Indexes (CRI), Hop-Count Routing Index (HRI) and Exponentially aggregated RI (ERI)
Different topologies (tree, tree with cycles)
Uses Bellman Ford or Distance Vector Routing Algorithm

19. Final Take away What P2p is Strengths and Weaknesses
Variety of Architectures and Algorithm Classification