15907163
Characterizing Web usage regularities with information foraging agents
Researchers have recently discovered several interesting, self-organized regularities from the World Wide Web, ranging from the structure and growth of the Web to the access patterns in Web surfing. What remains to be a great challenge in Web log mining is how to explain user behavior underlying observed Web usage regularities. We address the issue of how to characterize the strong regularities in Web surfing in terms of user navigation strategies, and present an information foraging agent-based approach to describing user behavior. By experimenting with the agent-based decision models of Web surfing, we aim to explain how some Web design factors as well as user cognitive factors may affect the overall behavioral patterns in Web usage.
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.
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.
206446606
In search of the wisdom web
W eb intelligence offers a new direction for scientific research and development, pushing technology toward manipulating the meaning of data and creating a distributed intelligence that can actually get things done. WI explores the fundamental and practical impact that artificial intelligence and advanced information technology will have on the next generation of Web-empowered systems, services, and environments. In an era dominated by the World Wide Web, Grid computing, intelligent-agent technology, and ubiquitous social computing, WI represents information technology’s next challenge.
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.
9921700
User-expertise modeling with empirically derived probabilistic implication networks
The application of user-expertise modeling for adaptive interfaces is confronted with a number of difficult challenges, namely, efficiency and reliability, the cost-benefit ratio, and the practical usability of user modeling techniques. We argue that many of these obstacles can be overcome by standard, automatic means of performing knowledge assessment. Within this perspective, we present the basis of a probabilistic user modeling approach, the POKS technique, which could serve as a standard user-expertise modeling tool.The POKS technique is based on the cognitive theory of knowledge structures: a formalism for the representation of the order in which we learn knowledge units (KU). The technique permits the induction of knowledge structures from a small number of empirical data cases. It uses an evidence propagation scheme within these structures to infer an individual's knowledge state from a sample of KU. The empirical induction technique is based, in part, on statistical hypothesis testing over conditional probabilities that are determined by the KUs' learning order.Experiments with this approach show that the technique is successful in partially inferring an individual's knowledge state, either through the monitoring of a user's behavior, or through a selective questioning process. However, the selective process, based on entropy minimization, is shown to be much more effective in reducing the standard error score of knowledge assessment than random sampling.
11417595
Distributed embedded systems for low power: a case study
Summary form only given. A multiple-processor system can potentially achieve higher energy savings than a single processor, because the reduced workload on each processor creates new opportunities for dynamic voltage scaling (DVS). However, as the cost of communication starts to match or surpass that of computation, many new challenges arise in making DVS effective in a distributed system under communication-intensive workload. We discuss implementation issues for supporting DVS on distributed embedded processors. We implemented and evaluated four distributed schemes: (1) DVS during I/O, (2) partitioning, (3) power-failure recovery, and (4) node rotation. We validated the results on a distributed embedded system with the Itsy pocket computers connected by serial links. Our experiments confirmed that a distributed system can create new DVS opportunities and achieve further energy savings. However, a surprising result was that aggregate energy savings do not translate directly into a longer battery life. In fact, the best partitioning scheme, which distributed the workload onto two nodes and enabled the most power-efficient CPU speeds at 30-50%, resulted in only 15% improvement in battery lifetime. Of the four techniques evaluated, node rotation showed the most measurable improvement to battery lifetime at 45% by balancing the discharge rates among the nodes.
445935
The TIGR rice genome annotation resource: annotating the rice genome and creating resources for plant biologists
Rice is not only a major food staple for the world's population but it also is a model species for a major group of flowering plants, the monocotyledonous plants. Draft genomic sequence of two subspecies of rice, Oryza sativa spp. japonica and indica ssp. are publicly available. To provide the community with a resource to data-mine the rice genome, we have constructed an annotation resource for rice (http://www.tigr.org/tdb/e2k1/osa1/). In this resource, we have annotated the rice genome for gene content, identified motifs/domains within the predicted genes, constructed a rice repeat database, identified related sequences in other plant species, and identified syntenic sequences between rice and maize. All of the data is available through web-based interfaces, FTP downloads, and a Distributed Annotation System.
195860670
Optimal stream replication for video simulcasting
Video simulcasting enables a sender to generate multiple streams for the same video program but at different rates, targeting receivers of different capacities. Each stream can then be distributed to the target receivers via broadcast or multicast channels. One of the critical issues in video simulcasting is to strike a balance between bandwidth consumption and the user satisfaction. This is because stream replication introduces redundancy which can potentially lead to excessive use of the bandwidth, while on the other hand there usually is a mismatch between a receiver's capacity and the limited choice of the stream bandwidths. We present a formal study on the above issue, which we refer as the optimal stream replication problem. We first formulate the optimal replication problem for a given session bandwidth budget and number of streams, with the objective of minimizing the expected mismatch for all the receivers in the session. A proper choice for the number of the replicated streams is critical in the overall bandwidth provisioning. Though it has been largely assumed that the number of streams is predetermined by service providers, we find that dynamic adjustment of stream number is possible in advanced video stream systems, such as the MPEG-4 Delivery Multimedia Integration Framework (DIMF), and systems employing fast video transcoding algorithms. Therefore, we also study the case of a flexible stream number, with the objective of jointly optimize the stream number and bandwidth allocated to each stream.
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.
13586161
Shape from regularities for interactive 3D reconstruction of piecewise planar objects from single images
3D object reconstruction from single 2D images has many applications in multimedia. This paper proposes an approach based on image regularities such as connectivity, parallelism, and orthogonality possessed by the objects with simple user interactions. It is assumed that the objects are piecewise planar. By representing the 3D objects as a shape vector consisting of the normals of the faces of the objects, we impose geometric constraints on this shape vector using the regularities of the objects. We derive a system of equations in terms of the shape vector and the focal length, which we can solve for the shape vector optimally. Experimental results on real images are shown to demonstrate the effectiveness of this method.