A new security architecture for SIP-based P2P computer networks

Many applications are transferred from C/S (Client/Server) mode to P2P (Peer-to-Peer) mode such as VoIP (Voice over IP). This paper presents a new security architecture, i.e. a trustworthy authentication algorithm of peers, for Session Initialize Protocol (SIP) based P2P computer networks. A mechanism for node authentication using a cryptographic primitive called one-way accumulator is proposed to secure the P2P SIP computer networks. It leverages the distributed nature of P2P to allow for distributed resource discovery and rendezvous in a SIP network, thus eliminating (or at least reducing) the need for centralized servers. The distributed node authentication algorithm is established for the P2P SIP computer networks. The corresponding protocol has been implemented in our P2P SIP experiment platform successfully. The performance study has verified the proposed distributed node authentication algorithm for SIP based P2P computer networks

Covert voice over internet protocol communications with packet loss based on fractal interpolation

The last few years have witnessed an explosive growth in the research of information hiding in multimedia objects, but few studies have taken into account packet loss in multimedia networks. As one of the most popular real-time services in the Internet, Voice over Internet Protocol (VoIP) contributes to a large part of network traffic for its advantages of real time, high flow, and low cost. So packet loss is inevitable in multimedia networks and affects the performance of VoIP communications. In this study, a fractal-based VoIP steganographic approach was proposed to realise covert VoIP communications in the presence of packet loss. In the proposed scheme, secret data to be hidden were divided into blocks after being encrypted with the block cipher, and each block of the secret data was then embedded into VoIP streaming packets. The VoIP packets went through a packet loss system based on Gilbert model which simulates a real network situation. And a prediction model based on fractal interpolation was built to decide whether a VoIP packet was suitable for data hiding. The experimental results indicated that the speech quality degradation increased with the escalating packet-loss level. The average variance of speech quality metrics (PESQ score) between the "no-embedding" speech samples and the “with-embedding” stego-speech samples was about 0.717, and the variances narrowed with the increasing packet-loss level. Both the average PESQ scores and the SNR values of stego-speech samples and the data retrieving rates had almost the same varying trends when the packet-loss level increased, indicating that the success rate of the fractal prediction model played an important role in the performance of covert VoIP communications

Framework to design new model of E-journals

Scientific journals are offered in many forms, some available in both print & electronic form & some in electronic forms only. E-journal have had opportunity to provide new features by taking advantages from the online environment. These features such as rapid publication, interactivity, multiple use, and non – linearity. The primary objectives to provide a new that, The new scholarly e-journals model will be design in this work should help a customer in a way that it become more efficient, more flexible and responsive to users demand , moreover, we will try to provide new ways of creating and delivery value by activation the way of display the information at the context

Computer aided mammography

This research investigated the state of art of computer aided detection systems for digital mammograms, and evaluated the related techniques in image pre-processing, feature extraction and classification of digital mammograms. Furthermore, this paper explored the further research directions for next generation CAD for mammograms. It was identified that computer-aided detection techniques for masses and microcalcifications have been extensively studied, but the detection techniques for architectural distortion and asymmetry in mammograms still are challenges

A Review on Computational Trust Models for Multi-agent Systems

Trust plays important roles on effective interaction and cooperation for multi-agent systems(MAS). This study aims at finding out the current situation and future trends of computational trustfor multi-agent systems. Through defining seven common compositional elements for the computational trust models, the study points out significant weaknesses in the current design. Finally, the paper figures out the future research trends through discussion and analysis around the strengths and weaknesses identified. Also the paper proposes an idea of using ontology and XML technologies such as RDF that allow systems to provide both human and machine readable annotations for trust models

Automatic Detection of Pectoral Muscle with the Maximum Intensity Change Algorithm

The accurate segmentation of pectoral muscle in mammograms is necessary to detect breast abnormalities in computer-aided diagnosis (CAD) of breast cancer. Based on morphological characteristics of pectoral muscle, a corner detector and the Maximum Intensity Change (MIC) algorithm were proposed in this research to detect the edge of pectoral muscle. The initial result shows that the proposed approach detected pectoral muscle with high quality

Performance of Database Driven Network Applications from the User Perspective

An understanding of performance of database driven network applications is critical in combating slow performance of e-commerce web sites, besides efficient web page design, and high quality and well-maintained web server equipment. This paper describes a method of measuring performance from the user viewpoint, which can help enormously in making realistic assessment of true performance of database driven applications. The performance measurements were taken at user locations by using several specially designed JavaScript functions along with ASP scripts. A performance study is presented in this paper, comparing performance of data access using stored procedures with the traditional way of querying a database. It is generally believed that stored procedures have performance benefits as they are pre-compiled. However, our study shows that the data access approach using stored procedures provides significant benefits (by about 30%) over the traditional approach for querying a commercial MySQL database, only when retrieving a substantial amount of data (at least 10,000 rows of data)

A series-parallel XML multisignature scheme for XML data authentication

XML signature technology is the major approach for ensuring XML data authentication. An XML signature should satisfy multiple data authentication requirements for XML data which pass a hierarchical network of responsibilities. Through investigation, existing XML multisignature schemes can not satisfy this requirement. This paper presents a series-parallel XML multisignature scheme based on Lu’s XML multisignature scheme. In the scheme presented, signers are divided into series or parallel subgroups according to their relationship, making the multisignature process closer to a natural signature-generation process. The scheme builds an XML data integrity-checking pool to provide integrity-checking for decomposed XML data. With this integrity-checking pool, signers can check integrity without the cooperation of others checkers. Testing shows that the scheme presented has a higher efficiency than repeated DSA or RSA, and satisfies application requirements in practice

Cigarette smoking, endothelial injury and cardiovascular disease

Despite the fact that the epidemiological evidence linking cigarette smoking with cardiovascular disease is overwhelming, the precise components of cigarette smoke responsible for this relationship and the mechanisms by which they exert their effect have not yet been elucidated. There are however, some promising pointers as a result of recent developments and this review concentrates on new evidence since earlier reviews of this topic. It is now known that the endothelium has a vastly more important role than was ever thought to be the case a decade ago. Its role in health and disease is increasingly understood, as is the relationship between endothelial injury and the development of atherosclerosis. There is considerable evidence that cigarette smoking can result in both morphological and biochemical disturbances to the endothelium both in vivo and in cell culture systems. Cigarette smoke is a complex mixture and only a few components have been extensively studied. Nicotine and carbon monoxide are much less damaging than is whole smoke. However the free radical components of cigarette smoke have been shown to cause damage in model systems. Further work will be necessary to consolidate the evidence base but the data reported in this review suggest that the free radical components of cigarette smoke may be responsible for the morphological and functional damage to endothelium that has been observed in model systems