Sai Ho Kwok

Interoperability of peer-to-peer file sharing protocols

Peer-to-Peer (P2P) file sharing software has brought a hot discussion on P2P file sharing among all businesses. Freenet, Gnutella, and Napster are the three most popular P2P file sharing applications. They use three distinct protocols and these protocols come with different characteristics. In this paper, we discuss the protocols of these P2P file sharing applications, in terms of the methodologies used for peer registry, query and content sharing. In order to maximize the benefit of P2P file sharing application that is to facilitate file sharing among various P2P file sharing applications, we propose a framework to integrate various P2P file sharing protocols using P2P gateway in this paper.

Participation incentive mechanisms in peer-to-peer subscription systems

Businesses are trying to explore new business opportunities in the newly emerging P2P technology applications. Motivating peer members through incentive mechanisms to supply contributions to the system and controlling free riding are suggested in this paper as important success factors for developing P2P-based business models. We review the psychology and community behavior literature in order to provide an explanation for the reasons why people get motivated to participate in P2P systems and to contribute to the peer community. Motivation can be classified into individual factors and interpersonal factors. Based on these factors, we develop incentive mechanisms that may help to induce peers to contribute and participate more and thus benefit the entire P2P system and community. In particular, we propose the inclusion of the following four features into P2P application environments: (i) contribution-reward mechanism, (ii) individual identity and profile generation, (iii) sub-community building, and (iv) peer recommendations.

A fast recursive shortest spanning tree for image segmentation and edge detection

This correspondence presents a fast recursive shortest spanning tree algorithm for image segmentation and edge detection. The conventional algorithm requires a complexity of o(n(2)) for an image of n pixels, while the complexity of our approach is bounded by O(n), which is a new lower bound for algorithms of this kind. The total memory requirement of our fast algorithm is 20% smaller.

Digital rights management for the online music business

Digital rights management has become a pressing concern for the online music business. Existing digital rights management systems are backed by two license management models, the tethered model and the untethered model. These two license management models focus on the management of payments and usage rights. The problems with these models are that the tethered model forces consumers to be online, while the untethered model provides relatively less security to the license residing locally. This paper proposes an enhanced license management model for the online music business, which integrates both models together and thus enables online and offline purchasing.

Peer-to-Peer Technology Business and Service Models: Risks and Opportunities

The sharing and downloading of information goods over peer-to-peer (P2P) networks has become a common way for millions of Internet users worldwide to find and trade music, software and other digital media files. In order for P2P networks to evolve into efficient economic marketplaces several issues need to be addressed. Peers may act in different roles, they can be contributors or consumers of the traded goods. Intermediaries may or may not emerge to better facilitate the trade. This paper discusses supplier risks and business opportunities arising from P2P service models. We propose some participation incentive mechanisms to mitigate free riding risk and improve the overall economic efficiency of P2P trading services and briefly outline how these could be implemented as software features in P2P application systems. This paper also examines the roles of P2P agents and concludes with a three-layer model that describes P2P services at the technology application level, the community application level, and th...

Efficient gamut clipping for color image processing using LHS and YIQ

Out-of-gamut problems exist in color image processing and color reproduction in different devices. Extensive research has been done on transforming out-of-gamut colors to the inside of the output devices color gamut for color reproduction. We focus on the out-of- gamut problem in color image processing. Luminance, hue, and satura- tion (LHS) and YIQ color coordinate systems are investigated. Efficient techniques for luminance and saturation processing and gamut clippings are presented. The efficient technique of luminance clipping for LHS is developed based on scaling, and the efficient technique of luminance clipping for YIQ is developed based on shifting. However, the efficient technique of saturation clipping for both LHS and YIQ is a combination of scaling and shifting. Such efficient techniques reduce the complexity of forward and backward transformations between the color representing the color coordinate system (RGB) and the processing color coordinate system (LHS or YIQ) significantly. Illustrations show the result of RGB, luminance, and saturation clippings. Saturation clipping is the best in terms of maintaining the hue and contrast of the original image. Experi- ments are also conducted to measure the efficiency of the proposed efficient techniques. It shows that the processing time is reduced by 27% comparing with the conventional technique using forward and backward color transformations.

Integration of digital rights management into the internet open trading protocol

Although digital rights management (DRM) has gained increasing importance in todays digital services and electronic commerce, it is not addressed explicitly in the Internet Open Trading Protocol (IOTP) specification. In this paper, we propose a digital rights management system (RMS) that is integrated into IOTP for electronic commerce applications and services. We introduce a rights insertion phase and a rights verification phase for IOTP. In the proposed framework, digital watermarking plays a very important role in facilitating digital rights management. The proposed digital rights management system was implemented on an online music web site and the proposed concepts and approaches proved to be successful.

Watermark-based copyright protection system security

Both researchers and industry players are asking: Just how easy is it to break a watermark-based copyright management system?

A LICENSE MANAGEMENT MODEL FOR PEER-TO-PEER MUSIC SHARING

The popularity of peer-to-peer (P2P) file sharing software has created a pressing need for digital music providers to resolve copyright and piracy problems of disseminating digital music through the Internet. Digital Rights Management (DRM) technology ensures protection of rights for distributed music over the Internet. Existing DRM systems emphasize protection based on business-to-consumer (B2C) distribution model, but do not tackle protection on a consumer-to-consumer (C2C) distribution model. This paper proposes a license management model to support not only typical music distribution models from music distributor to consumer (B2C), but also peer consumer to peer consumer (C2C) distribution model. The proposed license management model consists of two types of licenses, namely official licenses and peer licenses. These licenses are to be implemented in XrML. The concepts of these licenses facilitate both B2C and C2C distribution models. Functionality tests of the proposed model with certain common peer-to-peer sharing activities have been conducted.

Searching the peer-to-peer networks: the community and their queries

Peer-to-Peer (P2P) networks provide a new distributed computing paradigm on the Internet for file sharing. The decentralized nature of P2P networks fosters cooperative and non-cooperative behaviors in sharing resources. Searching is a major component of P2P file sharing. Several studies have been reported on the nature of queries of World Wide Web (WWW) search engines, but studies on queries of P2P networks have not been reported yet. In this report, we present our study on the Gnutella network, a decentralized and unstructured P2P network. We found that the majority of Gnutella users are located in the United States. Most queries are repeated. This may be because the hosts of the target files connect or disconnect from the network any time, so clients resubmit their queries. Queries are also forwarded from peers to peers. Findings are compared with the data from two other studies of Web queries. The length of queries in the Gnutella network is longer than those reported in the studies of WWW search engines. Queries with the highest frequency are mostly related to the names of movies, songs, artists, singers, and directors. Terms with the highest frequency are related to file formats, entertainment, and sexuality. This study is important for the future design of applications, architecture, and services of P2P networks.