Consider an ordered universe U , and a set T ⊂ U with |T | = n. The goal is to preprocess T , such that the following query can be answered efficiently: given x ∈ U , report the predecessor of x, i.e. max{y ∈ T | y < x}. One can also consider the dynamic problem, where elements are inserted and deleted into T . Let tq be the query time, and tu the update time. This is a fundamental search probl...

Peer-to-Peer (P2P) applications, such as Gnutella, are evolving to address some of the observed performance issues. In this paper, we analyze Gnutella behavior in 2003, 2005, and 2006. During this time, the protocol evolved from v0.4 to v0.6 to address problems with overhead of overlay maintenance and query traffic bandwidth. The goal of this paper is to understand whether the newer protocols a...

Most of the existing search algorithms for unstructured peer-to-peer (P2P) systems share one common approach: the requesting node sends out a keyword search query and the query message is repeatedly routed and forwarded to other peers in the overlay network. Due to multiple hops involved in query forwarding, the search may result in a long delay before it is answered. Furthermore, some incapabl...

On the one hand, the lack of structure of Peer-to-Peer (P2P) networks is key to their robustness and accessibility. On the other hand, this same lack of structure creates difficulties in efficiently searching the contents of the network. This search problem must be addressed for P2P networks to grow beyond the world of file sharing. To this end, we present a novel approach for describing the do...

In this paper, we discuss several strategies for e cient processing of three types of queries concerning mobile hosts; (1) queries to obtain the location of a mobile host (location queries), (2) queries to determine whether the mobile host is currently active (existence queries), and (3) queries to obtain a piece of information from a mobile host (data queries). Extracting ve fundamental strate...

At present many outsourcing organizations need sharing of the information via on-demand access. Information Brokering System (IBS) have been already proposed to connect large-scale loosely-federated data sources via brokering overlay. But there are some attacks with these traditional IBS, namely attribute-correlation attack and inference attack. To overcome these attacks here we are proposing t...

vspace{0.2cm}In this paper, we design a data structure for the following problem. Let $pi$ be an $x$-monotone trajectory with $n$ vertices in the plane and $epsilon >0$. We show how to preprocess $pi$ and $epsilon$ into a data structure such that for any horizontal query segment $Q$ in the plane, one can quickly determine the minimal continuous fraction of $pi$ whose Fr{'e}chet and Hausdo...

Future sensor networks will be composed of a large number of densely deployed sensors/actuators. A key feature of such networks is that their nodes are untethered and unattended. Consequently, energy efficiency is an important design consideration for these networks. Motivated by the fact that sensor network queries may often be geographical, we design and evaluate an energy efficient routing a...