The performance of the ALOHA and CSMA MAC protocols are analyzed in spatially distributed wireless networks. The main system objective is correct reception of packets, and thus the analysis is performed in terms of outage probability. In our network model, packets belonging to specific transmitters arrive randomly in space and time according to a 3-D […]
Distributed Sensing in Multiband Cognitive Networks
We consider a short range cognitive network searching for spectrum holes from very wide bandwidth. In practice, one cognitive user can sense only a small portion of spectrum. Unfortunately, in fading environment a reliable detection scheme requires measurements collected by multiple users. Because of that, it is unreasonable to expect a small-sized network to sense […]
Valuable Detours: Least-Cost Anypath Routing
In many networks, it is less costly to transmit a packet to any node in a set of neighbors than to one specific neighbor. This observation was previously exploited by opportunistic routing protocols by using single-path routing metrics to assign to each node a group of candidate relays for a particular destination. This paper addresses […]
SRLG Failure Localization in Optical Networks
We introduce the concepts of monitoring paths (MPs) and monitoring cycles (MCs) for unique localization of shared risk linked group (SRLG) failures in all-optical networks. An SRLG failure causes multiple links to break simultaneously due to the failure of a common resource. MCs (MPs) start and end at the same (distinct) monitoring location(s). They are […]
Communication Cost Minimization in Wireless Sensor and Actor Networks for Road Surveillance
In recent years, wireless sensor and actor networks (WSANs) have been extensively deployed to monitor physical environment and facilitate decision making based on data collected. Emerging applications such as road surveillance highlight some interesting research issues in WSANs, including coordination problems in sensor-actor or actor-actor communications. In this paper, the issue of choosing a set […]
Loss Performance Modeling for Hierarchical Heterogeneous Wireless Networks With Speed-Sensitive Call Admission Control
A hierarchical overlay structure is an alternative solution that integrates existing and future heterogeneous wireless networks to provide subscribers with better mobile broadband services. Traffic loss performance in such integrated heterogeneous networks is necessary for an operator’s network dimensioning and planning. This paper investigates the computationally efficient loss performance modeling for multiservice in hierarchical heterogeneous […]
Lossy Compression and Iterative Reconstruction for Encrypted Image
This work proposes a novel scheme for lossy compression of an encrypted image with flexible compression ratio. A pseudorandom permutation is used to encrypt an original image, and the encrypted data are efficiently compressed by discarding the excessively rough and fine information of coefficients generated from orthogonal transform. After receiving the compressed data, with the […]
Computational Perceptual Features for Texture Representation and Retrieval
A perception-based approach to content-based image representation and retrieval is proposed in this paper. We consider textured images and propose to model their textural content by a set of features having a perceptual meaning and their application to content-based image retrieval. We present a new method to estimate a set of perceptual textural features, namely […]
Color Extended Visual Cryptography Using Error Diffusion
Color visual cryptography (VC) encrypts a color secret message into color halftone image shares. Previous methods in the literature show good results for black and white or gray scale VC schemes, however, they are not sufficient to be applied directly to color shares due to different color structures. Some methods for color visual cryptography are […]
Rumor Riding: Anonymizing Unstructured Peer-to-Peer Systems
Although anonymizing Peer-to-Peer (P2P) systems often incurs extra traffic costs, many systems try to mask the identities of their users for privacy considerations. Existing anonymity approaches are mainly path-based: peers have to pre-construct an anonymous path before transmission. The overhead of maintaining and updating such paths is significantly high. We propose Rumor Riding (RR), a […]
- « Previous Page
- 1
- …
- 13
- 14
- 15
- 16
- 17
- …
- 28
- Next Page »