7030276
Adaptive Query-Caching in Peer-to-Peer Systems
Peer-to-Peer (P2P) architectures are very prevalent in today’s Internet. Lots of P2P file sharing systems using Gnutella protocol emerge out and draw attractions of millions of people. The “flooding” search mechanism of Gnutella makes it easy to be deployed, but also spawns numerous messages which leads to serious scalability problems. However, the locality discovered in both user’s share files and queries, enables us to use query-caching to shorten the search length and reduce the messages traffic. This paper makes an extensive study of query-caching in P2P systems and proposes an adaptive query-caching mechanism to manage the cached query reply messages according to the heterogeneity of the uptime of different peers. Along with several other techniques we proposed, our approach achieves a 30% reduction of average search length and a 61% reduction of query message traffic comparing with the previous query-caching mechanisms in the simulation, which indicates that our approach makes Gnutella more scalable.
14282862
Design and Deployment of Locality-Aware Overlay Multicast Protocol for Live Streaming Services
This paper presents the design and deployment of a locality-aware overlay multicast protocol called Anysee. The key idea of Anysee is to use the geometrical information of end hosts to construct the locality-aware overlay data delivery tree such that nearby users in the underlying network can be organized into nearby subtrees. The prototype of Anysee has been widely used in CERNET. Logging traces obtained from broadcasting 2004 Athens Olympic Games over 16 days have shown that the performance of Anysee, such as end-to-end delay and absolute data delivery delay, significantly outperforms that of randomly constructed overlay multicast.
21169395
Small Circuit Double Covers of Cubic Multigraphs
Let G be a two-connected graph. A family F of circuits of G is called a circuit double cover (CDC) if each edge of G is contained in exactly two circuits of F. In this paper, we show that if a simple cubic graph G (G ? K4) of order n has a CDC, then G has a CDC containing at most n/2 circuits. This result establishes the equivalence of the circuit double cover conjecture (due to Szekeres, Seymour) and the small circuit double cover conjecture (due to Bondy) for any cubic graph. Actually, a stronger result is obtained in this paper for all loopless cubic graphs. Another result in this paper establishes an upper bound on the size of any CDC of a cubic graph.
14923326
Co-histogram and Image Degradation Evaluation
The tool for image degradation evaluation addressed in this paper is called co-histogram, which is a statistic graph generated by counting the corresponding pixel pairs of two images. The graph is a two-dimensional joint probability distribution of the two images. A co-histogram shows how the pixels are distributed among combinations of two image pixel values. By means of co-histogram, we can have a visual understanding of PSNR, and the symmetry of a co-histogram is also significant for objective evaluation of image degradation. Our experiments with image degradation models of image compression, convolution blurring and geometric distortion perform the importance of the co-histogram.
45852164
An Agent-Based Hybrid Intelligent System for Financial Investment Planning
Many complex problems including financial investment planning require hybrid intelligent systems that integrate many intelligent techniques including expert systems, fuzzy logic, neural networks, and genetic algorithms. however, hybrid intelligent systems are difficult to develop due to complicated interactions and technique incompatibilities. this paper describes a hybrid intelligent system for financial investment planning that was built from agent points of view. this system currently consists of 13 different agents. the experimental results show that all agents in the system can work cooperatively to provide reasonable investment advice. the system is very flexible and robust. the success of the system indicates that agent technologies can significantly facilitate the construction of hybrid intelligent systems.
6709890
An agent-based hybrid framework for database mining
While knowledge discovery in databases (KDD) is defined as an iterative sequence of the following steps: data pre-processing, data mining, and post data mining, a significant amount of research in data mining has been done, resulting in a variety of algorithms and techniques for each step. However, a single data-mining technique has not been proven appropriate for every domain and data set. Instead, several techniques may need to be integrated into hybrid systems and used cooperatively during a particular data-mining operation. That is, hybrid solutions are crucial for the success of data mining. This paper presents a hybrid framework for identifying patterns from databases or multi-databases. The framework integrates these techniques for mining tasks from an agent point of view. Based on the experiments conducted, putting different KDD techniques together into the agent-based architecture enables them to be used cooperatively when needed. The proposed framework provides a highly flexible and robust data-mining platform and the resulting systems demonstrate emergent behaviors although it does not improve the performance of individual KDD techniques.
3953733
TCP-Real: receiver-oriented congestion control
We introduce a receiver-oriented approach to congestion control, demonstrated by an experimental protocol, TCP-Real. The protocol allows for a measurement-based transmission strategy, which complements the "blind" increase/ decrease window adjustments. Owing to its design, the protocol displays an inherent property to produce comprehensive dynamics in heterogeneous environments with wired or wireless networks and delay-sensitive or -tolerant applications. TCP-Real controls congestion as standard TCP does. However, its receiver-oriented nature and its "wave" communication pattern allow for two amending mechanisms: (i) congestion avoidance, which reduces unnecessary transmission gaps that hurt the performance of time-constrained applications, and (ii) advanced error detection and classification, which designates recovery tactics responsive to the nature of the errors, thereby enhancing the protocol performance over wireless links or asymmetric paths.We detail the protocol mechanisms and specification and we report extensively on the comparative fairness and efficiency evaluation of standard TCP, TCP-Real, and TCP-friendly protocols for both delay-tolerant and -sensitive applications and in both wired and wireless networks.