Numerical Approach of the Influence of Geometric Properties on the Absorbing in Photonic Crystal

In the proposed study, an investigation has been carried out in order to find a material efficient structure, capable of harnessing maximum solar spectrum. A material efficient structure designed using a one dimensional photonic crystal (1D PC) for amorphous silicon. Silicon material is used as it leads to environmental friendly design. The principal objective of this study is to maximize the photon absorption, keeping reflection to a minimum. The influence of geometric parameters on the absorption is studied by using the Finite element method (FEM). The results show that the absorption is affected by the geometry parameters. The optimum parameters of the proposed structure are period (a = 480 nm), a filling factor (ff = 50 %) and depth (d = 150 nm). The increase of absorption in the lower region where the wavelengths are around 480 nm, is explained by the reduction of the effective index resulting from the structure of the absorbent layer. For wavelengths between 480 nm and 600 nm, the absorption is directly related to existing Fabry-Perot modes within the absorbent layer. Creating additional absorption peaks at wavelengths above about 600 nm weakly absorbed normally comes from the coupling of the incident light with slow Bloch modes of PC located above the light line

Fair signature exchange via delegation on ubiquitous networks

This paper addresses the issue of autonomous fair signature exchange in emerging ubiquitous (u-) commerce systems, which require that the exchange task be delegated to authorised devices for its autonomous and secure execution. Relevant existing work is either inefficient or ineffective in dealing with such delegated exchange. To rectify this situation, this paper aims to propose an effective, efficient and secure solution to the delegated exchange to support the important autonomy feature offered by u-commerce systems. The proposed work includes a novel approach to symmetric-key based verifiable proxy encryption to make the exchange delegation flexible, efficient and simple to implement on resource-limited devices commonly used in u-commerce systems. This approach is then applied to design a new exchange protocol. An analysis of the protocol is also provided to confirm its security and fairness. Moreover, a comparison with related work is presented to demonstrate its much better efficiency and simplicity

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

A novel scalable hybrid architecture for MMOG

We present a novel MMOG Hybrid P2P architecture and detail its key components, topology and protocols. We highlight the main components which lie at the heart of the proposed solution, and their roles, and describe the methods of tackling the key scenarios which are faced by the architecture during gameplay. For each role, we discuss the interactions that exist between them and describe the protocols that will be used for inter-role communication to perform the atomic actions necessary for maintaining the consistency and responsiveness of an MMOG such as peer addition, peer removal, group transfer, object change persistency and many more. We conclude the chapter with a comparison of the architecture against several existing P2P MMOG frameworks, discussing the differences which exist between them and how the novel Hybrid-P2P architecture we propose aims to address their flaws

A Novel Multi-Agent Planning System for Digital Interactive Storytelling

Digital Interactive Storytelling (DIS) is a relatively novel area of computer entertainment that aims at investigating interactive applications capable of generating consistent, emergent, and rich stories. To provide new solutions for DIS, we designed and are implementing and evaluating a novel multi-agent DIS framework, DIEGESIS, which includes agents' coordination and new planning and re-planning solutions. In this article, we discuss the design and implementation of DIEGESIS, explaining in detail the mechanisms of our planning algorithms, and the story execution and agent coordination algorithms, along with a planning methods evaluation and agent planning and coordination examples. We are currently in the process of creating a large DIS scenario, involving the story of Homer's Troy, with several levels that will allow us to further evaluate and expand our system

Capturing and Sharing Human Digital Memories with the Aid of Ubiquitous Peer– to–Peer Mobile Services

The explosion of mobile computing and the sharing of content ubiquitously has enabled users to create and share memories instantly. Access to different data sources, such as location, movement, and physiology, has helped to create a data rich society where new and enhanced memories will form part of everyday life. Peer–to–Peer (P2P) systems have also increased in popularity over the years, due to their ad hoc and decentralized nature. Mobile devices are “smarter” and are increasingly becoming part of P2P systems; opening up a whole new dimension for capturing, sharing and interacting with enhanced human digital memories. This will require original and novel platforms that automatically compose data sources from ubiquitous ad-hoc services that are prevalent within the environments we occupy. This is important for a number of reasons. Firstly, it will allow digital memories to be created that include richer information, such as how you felt when the memory was created and how you made others feel. Secondly, it provides a set of core services that can more easily manage and incorporate new sources as and when you are available. In this way memories created in the same location, and time are not necessarily similar – it depends on the data sources that are accessible. This paper presents DigMem, the initial prototype that is being developed to utilize distributed mobile services. DigMem captures and shares human digital memories, in a ubiquitous P2P environment. We present a case study to validate the implementation and evaluate the applicability of the approach

Networking Middleware and Online-Deployment Mechanisms for Java-Based Games

Currently, web-based online gaming applications are predominately utilising Adobe Flash or Java Applets as their core technologies. These games are often casual, two-dimensional games and do not utilise the specialist graphics hardware which has proliferated across modern PCs and Consoles. Multi-user online game play in these titles is often either non-existent or extremely limited. Computer games applications which grace the current generation of consoles and personal computers are designed to utilise the increasingly impressive hardware power at their disposal. However, these are commonly distributed using a physical medium or deployed through custom, proprietary networking mechanisms and rely upon platform-specific networking APIs to facilitate multi-user online game play. In order to unify the concepts of these disparate styles of gaming, this paper presents two interconnected systems which are implemented using Java Web Start and JXTA P2P technologies, providing a platform-independent framework capable of deploying hardware accelerated cross-platform, cross-browser online-enabled Java games, as part of the Homura Project

Hosting critical infrastructure services in the cloud environment considerations

Critical infrastructure technology vendors will inevitability take advantage of the benefits offered by the cloud computing paradigm. While this may offer improved performance and scalability, the associated security threats impede this progression. Hosting critical infrastructure services in the cloud environment may seem inane to some, but currently remote access to the control system over the internet is commonplace. This shares the same characteristics as cloud computing, i.e., on-demand access and resource pooling. There is a wealth of data used within critical infrastructure. There needs to be an assurance that the confidentiality, integrity and availability of this data remains. Authenticity and non-repudiation are also important security requirements for critical infrastructure systems. This paper provides an overview of critical infrastructure and the cloud computing relationship, whilst detailing security concerns and existing protection methods. Discussion on the direction of the area is presented, as is a survey of current protection methods and their weaknesses. Finally, we present our observation and our current research into hosting critical infrastructure services in the cloud environment, and the considerations for detecting cloud attacks. © 2015 Inderscience Enterprises Ltd

Intelligent Agents for Automated Cloud Computing Negotiation

Presently, cloud providers offer “off-the-shelf” Service Level Agreements (SLA), on a “take it or leave it” basis. This paper, alternatively, proposes customized SLAs. An automated negotiation is needed to establish customized SLAs between service providers and consumers with no previous knowledge of each other. Traditional negotiations between humans are often fraught with difficulty. Thus, in this work, the use of intelligent agents to represent cloud providers and consumers is advocated. Rubinstein’s Alternating Offers Protocol offers a suitable technical solution for this challenging problem. The purpose of this paper is to apply the state-of-the-art in negotiation automated algorithms/agents within a described Cloud Computing SLA framework, and to evaluate the most appropriate negotiation approach based on many criteria

Coarticulation and speech synchronization in MPEG-4 based facial animation

In this paper, we present a novel coarticulation and speech synchronization framework compliant with MPEG-4 facial animation. The system we have developed uses MPEG-4 facial animation standard and other development to enable the creation, editing and playback of high resolution 3D models; MPEG-4 animation streams; and is compatible with well-known related systems such as Greta and Xface. It supports text-to-speech for dynamic speech synchronization. The framework enables real-time model simplification using quadric-based surfaces. Our coarticulation approach provides realistic and high performance lip-sync animation, based on Cohen-Massaro’s model of coarticulation adapted to MPEG-4 facial animation (FA) specification. The preliminary experiments show that the coarticulation technique we have developed gives overall good and promising results when compared to related techniques