Region Adaptive Digital Image Watermarking System Using DWT-SVD Algorithm

Improving the robustness of watermark in withstanding attacks has been one of the main research objectives in digital image watermarking. In this paper we propose a novel region-adaptive watermarking technique that can provide improvements in both robustness and visual quality of the watermarks when compared to the original, non-region-adaptive, embedding technique. The proposed technique, which is derived from our previously published research finding, shows that the relative difference in spectral distributions between the watermark data and the host image plays an important role in improving the watermark robustness and transparency. Keywords – Quad-tree algorithm, discrete wavelet transform, region-based watermarking system

Region Adaptive Digital Image Watermarking System using DWT-SVD algorithm

Improving the robustness of watermark in withstanding attacks has been one of the main research objectives in digital image watermarking. In this paper we propose a novel region-adaptive watermarking technique that can provide improvements in both robustness and visual quality of the watermarks when compared to the original, non-region-adaptive, embedding technique. The proposed technique, which is derived from our previously published research finding, shows that the relative difference in spectral distributions between the watermark data and the host image plays an important role in improving the watermark robustness and transparency

Investigating Sharing in Memory for Life Systems

Memory for Life (M4L) systems store and organize life events captured by people in digital form using their cameras, mobile phones and so on. This paper describes M4L systems and the challenges for sharing digital events. Based on the challenges, an investigation is carried out in order to find a suitable technology that allows sharing of digital events according to the social network of a user. For this purpose, Web-based online social networks and peer-to-peer networks are particularly studied. The requirements for a social P2P model for sharing human digital events (HDEs) are suggested as future work

Memory Threads: Organizing Digital Memories to Organize Social P2P Networks

Human remember their memories based on some reference which helps in recalling those memories. These references are usually common for many people, objects, places and so on. We organize human digital memories in the form of memory threads, according to the references of the memories in order to present information about different places, persons, etc. We organize peers in our Entity-based social peer-to-peer network according to memory threads in the form of memory threads-based communities. In our approach, peers having human digital memories with similar reference keys are grouped together under certain criteria. The criteria for thread selects peers with similar digital memories and arrange them in a specific order that define a structure of thread, which allows tracing via memories and accessing peers at different locations in threads easily. This approach is more scalable because it brings the most similar peer together in a community of similar peer. The known location of peer and data allows fast data searching. Also, a community presents useful information about the entity in network

Thwarting Sybil Attackers in Reputation-based Scheme in Mobile Ad hoc Networks

Routing in mobile ad hoc networks is performed in a distributed fashion where each node acts as host and router, such that it forwards incoming packets for others without relying on a dedicated router. Nodes are mostly resource constraint and the users are usually inclined to conserve their resources and exhibit selfish behaviour by not contributing in the routing process. The trust and reputation models have been proposed to motivate selfish nodes for cooperation in the packet forwarding process. Nodes having bad trust or reputation are detected and secluded from the network, eventually. However, due to the lack of proper identity management and use of non-persistent identities in ad hoc networks, malicious nodes can pose various threats to these methods. For example, a malicious node can discard the bad reputed identity and enter into the system with another identity afresh, called whitewashing. Similarly, a malicious node may create more than one identity, called Sybil attack, for self-promotion, defame other nodes, and broadcast fake recommendations in the network. These identity-based attacks disrupt the overall detection of the reputation systems. In this paper, we propose a reputation-based scheme that detects selfish nodes and deters identity attacks. We address the issue in such a way that, for normal selfish nodes, it will become no longer advantageous to carry out a whitewash. Sybil attackers are also discouraged (i.e., on a single battery, they may create fewer identities). We design and analyse our rationale via game theory and evaluate our proposed reputation system using NS-2 simulator. The results obtained from the simulation demonstrate that our proposed technique considerably diminishes the throughput and utility of selfish nodes with a single identity and selfish nodes with multiple identities when compared to the benchmark scheme

A community‐based social P2P network for sharing human life digital memories

Social peer‐to‐peer (P2P) networks are usually designed by reflecting a user's interest/behavior for structuring the underlying network. Human interest is affected by various factors such as age, locality, and so on which changes after some time. The behavior when reflected in a network, results in peers moving within the network in order to connect the peer with peers of the same behavior/interest. Especially in community‐based schemes when a peer leaves a community the data that a peer was sharing will not be accessible in the same community anymore. It has an effect on the performance of the network due to the inaccessibility of data and the unavailability of connections, which affect network robustness. We address this issue by considering entities in data in the form of digital memories of a user and structuring network according to entity‐based communities. The simulation results for the proposed entity‐based community are demonstrated, which shows the effect on network performance during varying network size and traffic