33842812
Anycast-Based Cooperative Proxy Caching
As one of the most popular applications currently running on the Internet, the World Wide Web is of an exponential growth in size, which results in the network congestion and server overloading. Web caching as an important technique aims at reducing network traffic, server load, and user-perceived retrieval delays by replicating popular contents on proxy caches. In our paper, we develop an anycast-based cooperative web proxy caching mechanism. It puts response time, hop counts, self-organized load balancing, adaption, and self-configuration as primary concerns. In our scheme, anycast is used to bring a server “nearest” to a client to improve overall performance, all proxies in a local network consists an anycast group. The object placement and replacement problems are formulated as an optimization problem and the solution is obtained by using an anycast-based cooperative proxy caching algorithm. Some simulation experiments have been conduced to evaluate the proposed scheme in terms of a wide range of performance metrics. Analytical and experimental results show that our algorithm outperforms some existing algorithms in response time, hop counts.
14332748
Agent network topology and complexity
In this paper, we examine two multi-agent based representations of SATs and further experimentally study the topologies of resulting agent networks. We show that different representations will make agent networks manifest different topologies. In one presentation, the resulting agent network show obviously small-world topologies. Generally speaking, a small-world topology will computationally harden a search process. Therefore, we propose a guiding design principle that to solve a search problem by a multi-agent system, it should avoid having small-worlds among agents and it should maintain balanced intra- and inter-agent computational complexity.
37149853
New Challenges in the World Wide Wisdom Web (W4) Research
This talk addresses the research and development needs for creating the new paradigm shift in Internet computing. In particular, it presents a promising answer to such needs, called the World Wide Wisdom Web (W4), and identifies several research challenges and enabling technologies in developing the W4.
5220045
A study of the performance and parameter sensitivity of adaptive distributed caching
A self-organized approach to manage a distributed proxy system called Adaptive Distributed Caching (ADC) has been proposed previously [8]. We model each proxy as an autonomous agent that is equipped to decide how to deal with client requests using local information. Experimental results show that our ADC algorithm is able to compete with typical hashing-based approaches. This paper gives a full description of the self-organizing distributed algorithm, with a performance comparison based on hits and hops rate. Additional evaluation of the parameters caching-, multiple- and single-table size is also presented.
15358098
Multi-agent oriented constraint satisfaction
This paper presents a multi-agent oriented method for solving CSPs (Constraint Satisfaction Problems). In this method, distributed agents represent variables and a two-dimensional grid-like environment in which the agents inhabit corresponds to the domains of the variables. Thus, the positions of the agents in such an environment constitute the solution to a CSP. In order to reach a solution state, the agents will rely on predefined local reactive behaviors; namely, better-move, least-move, and random-move. While presenting the formalisms and algorithm, we will analyze the correctness and complexity of the algorithm, and demonstrate the proposed method with two benchmark CSPs, i.e., n-queen problems and coloring problems. In order to further determine the effectiveness of different reactive behaviors, we will examine the performance of this method in deriving solutions based on behavior prioritization and different selection probabilities.
9274730
Agent-based, energy efficient routing in sensor networks
Amorphous computing aims at discovering new approaches for programming and controlling vast number of computational entities. So far, most related studies are mainly on the problem of pattern formation. However, there still remains a great challenge: how to enable amorphous entities to handle computationally hard problems? In order to tackle this challenge, we propose to take the energy efficient routing problem in sensor networks as a special topic for study, due to the similar characteristics of sensor nodes and amorphous entities. In the paper, each data packet sent from a source node is carried by an autonomous mobile data agent, which can make its own routing decision based on its local information. Moreover, we propose a novel data routing idea on energy efficient route choosing. Simulation results demonstrate that our routing schemes based on the proposed idea can achieve a better performance of energy load balancing in the network, and a shorter time delay for data agents to travel from a source to a sink than other schemes discussed in the paper. Furthermore, by endowing the data agents with some intelligence, data aggregation can be performed locally and dynamically during their transmissions in sensor networks.
9690577
Automatic Camera Calibration and Scene Reconstruction with Scale-Invariant Features
The goal of our research is to robustly reconstruct general 3D scenes from 2D images, with application to automatic model generation in computer graphics and virtual reality. In this paper we aim at producing relatively dense and well-distributed 3D points which can subsequently be used to reconstruct the scene structure. We present novel camera calibration and scene reconstruction using scale-invariant feature points. A generic high-dimensional vector matching scheme is proposed to enhance the efficiency and reduce the computational cost while finding feature correspondences. A framework for structure and motion is also presented that better exploits the advantages of scale-invariant features. In this approach we solve the “phantom points” problem and this greatly reduces the possibility of error propagation. The whole process requires no information other than the input images. The results illustrate that our system is capable of producing accurate scene structure and realistic 3D models within a few minutes.
1291895
A proxy-assisted adaptation framework for object video multicasting
Video multicast is a challenging problem due to the heterogeneous and best-effort nature of the Internet. In this paper, we present a novel video multicast framework that exploits the potential of object scalability offered by MPEG-4. Specifically, we introduce the concept of object transmission proxy (OTP), which filters incoming streams using object-based bandwidth adaptation to meet dynamic network conditions. Multiple OPTs can form an overlay network that interconnects diverse multicast islands with semi-uniform demands within each single island. We concur with the wisdom that an application best knows the utility of its data. Hence, the bandwidth-adaptation algorithm for the OTPs adaptively allocates bandwidth among video objects according to their respective utilities and then performs application-level filtering based on an effective stream classification and packetization scheme. Extensive simulation results demonstrate that our framework has substantial performance improvement over conventional bandwidth-adaptation schemes. It is particularly suitable for object-based video multicasting where the objects are of different importance.
10834714
Safety analysis of software product lines using state-based modeling
The analysis and management of variations (such as optional features) are central to the development of safety-critical, software product lines. However, the difficulty of managing variations, and the potential interactions among them, across an entire product line currently hinders safety analysis in such systems. The work described here contributes to a solution by integrating safety analysis of a product line with model-based development. This approach provides a structured way to construct a state-based model of a product line having significant, safety-related variations. The process described here uses and extends previous work on product-line software fault tree analysis to explore hazard-prone variation points. The process then uses scenario-guided executions to exercise the state model over the variations as a means of validating the product-line safety properties. Using an available tool, relationships between behavioral variations and potentially hazardous states are systematically explored and mitigation steps are identified. The paper uses a product line of embedded medical devices to demonstrate and evaluate the process and results
14806639
A unified framework for resource discovery and QoS-aware provider selection in ad hoc networks
With the rising popularity of network-based applications and the potential use of mobile ad hoc networks in civilian life, an efficient resource discovery service is needed in such networks for quickly locating resource providers. In addition, to improve user experience, QoS awareness is also crucial. In this paper, we identify the challenges when basic resource discovery techniques for the Internet are used in mobile ad hoc networks. We then propose a framework that provides a unified solution to the discovery of resources and QoS-aware selection of resource providers. The key entities of this framework are a set of self-organized discovery agents. These agents manage the directory information of resources using hash indexing. They also dynamically partition the network into domains and collect intra- and inter-domain QoS information to select appropriate providers. Simulation results show that our framework improves the QoS delivered to the clients, while the cost and response time are kept at a low level.
14115714
Energy-efficient compressed address transmission
To realize energy-efficient buses in current nanometer-scale technologies, techniques like compression or encoding that exploit information redundancy have been explored. However, available compression techniques for buses do not always ensure energy-efficient transmission of compressed information. In this work, we present various techniques that can be used with compression schemes for buses to ensure high energy efficiency. Our best scheme, applied to a stream of 38-bit addresses issued in a typical microprocessor, yields about 14.7% energy reduction on the average across a wide range of compressed bus widths ranging and over many SPEC CPU2000 benchmarks. Our proposed techniques especially perform better - up to 28.8% energy reduction is obtained - for narrower bus widths in the range 8-16 bits.