• Journal of Korea Multimedia Society
• /
• v.11 no.10
• /
• pp.1409-1419
• /
• 2008

Inauthentic resources can be easily spread by P2P (Peer-to-Peer) participants due to the openness and anonymity of P2P networks. A possible way to restrict the distribution of inauthentic resources and prevent malicious peers from joining P2P networks is to exploit peers' reputation which reflect their past behaviors and are also helpful to predict peers' future behaviors. There is a possibility that some peers intentionally plays along with other peers in order to increase/decrease its reputation through false feedback exchanges. Therefore, we propose a new reputation management scheme, called TrustRRep (Trustable Resource sharing service using Reputation) scheme, which improves the trustworthiness and efficiency of P2P networks by identifying peers who give false feedback. The TrustRRep scheme is also capable of providing peers with the trustworthiness of shared resources by discriminating resources distributed by malicious peers. We implement the proposed TrustRRep scheme on the NS-2 simulator for evaluating its performance compared to the recent reputation management work available in literature. A case study on simulations shows that the proposed reputation management scheme yields efficient performance in terms of the minimal download ratio and dissemination of inauthentic resources, the efficient identification of peers who give false feedback, and the provisioning of the trustworthiness of peers' reputation. It also shows that the proposed TrustRRep scheme imposes the restrictions of participating P2P networks on a malicious peers by diminishing its trust value.

• Journal of IKEEE
• /
• v.9 no.2 s.17
• /
• pp.123-135
• /
• 2005

3GPP RLC protocol specification adopted a window-controlled selective-repeat ARQ scheme for provisioning reliable data transmission. Inevitably, the re-ordering issue arises in the 3GPP's ARQ since it belongs to the selective-repeat ARQ clan. A long re-ordering time results in the degradation of throughput and delay performance, and may invoke the overflow of the re-ordering buffer. Also, the re-ordering time must be regulated to meet the requirements of some services which are both loss-sensitive and delay-sensitive. In the 3GPP's ARQ, we may deflate the occupancy of the re-ordering buffer by reducing the window size and/or length of the status report period. Such a decrease, however, deteriorates the throughput and delay performance and encroaches the resource of the reverse channel. Aiming at reducing the occupancy at the re-ordering buffer while suppressing the degradation of throughput and delay performance, we propose threshold-dependent occupancy control schemes, identified as post-threshold and pre-threshold schemes, as supplements to the 3GPP's ARQ. For judging the effectiveness of the proposed schemes, we investigate peak occupancy, maximum throughput and average delay in the practical environment involving fading channels. From the simulation results, we observe that the proposed schemes invoke the performance trade-off between occupancy and throughput in general. Also, we reveal that the post-threshold scheme is able to improve the throughput and delay performance of the ordinary 3GPP's ARQ without inflating the occupancy of the re-ordering buffer.

• The Journal of the Korea Contents Association
• /
• v.15 no.5
• /
• pp.570-581
• /
• 2015

In recent years, many institutions predict that cloud services and big data will be popular IT trends in the near future. A number of leading IT vendors are focusing on practical solutions and services for cloud and big data. In addition, cloud has the advantage of unrestricted in selecting resources for business model based on a variety of internet-based technologies which is the reason that provisioning and virtualization technologies for active resource expansion has been attracting attention as a leading technology above all the other technologies. Big data took data prediction model to another level by providing the base for the analysis of unstructured data that could not have been analyzed in the past. Since what cloud services and big data have in common is the services and analysis based on mass amount of data, efficient operation and designing of mass data has become a critical issue from the early stage of development. Thus, in this paper, I would like to establish data processing architecture based on technological requirements of mass data for cloud and big data services. Particularly, I would like to introduce requirements that must be met in order for distributed file system to engage in cloud computing, and efficient compression technology requirements of mass data for big data and cloud computing in terms of cost-saving, as well as technological requirements of open-source-based system such as Hadoop eco system distributed file system and memory database that are available in cloud computing.