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Extensive Experiments (extensive + experiment)
Selected AbstractsWeb Discovery and Filtering Based on Textual Relevance Feedback LearningCOMPUTATIONAL INTELLIGENCE, Issue 2 2003Wai Lam We develop a new approach for Web information discovery and filtering. Our system, called WID, allows the user to specify long-term information needs by means of various topic profile specifications. An entire example page or an index page can be accepted as input for the discovery. It makes use of a simulated annealing algorithm to automatically explore new Web pages. Simulated annealing algorithms possess some favorable properties to fulfill the discovery objectives. Information retrieval techniques are adopted to evaluate the content-based relevance of each page being explored. The hyperlink information, in addition to the textual context, is considered in the relevance score evaluation of a Web page. WID allows users to provide three forms of the relevance feedback model, namely, the positive page feedback, the negative page feedback, and the positive keyword feedback. The system is domain independent and does not rely on any prior knowledge or information about the Web content. Extensive experiments have been conducted to demonstrate the effectiveness of the discovery performance achieved by WID. [source] DTI-DROID: Diffusion tensor imaging-deformable registration using orientation and intensity descriptorsINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2010Madhura Ingalhalikar Abstract This article presents a method (DROID) for deformable registration of diffusion tensor (DT) images that utilizes the full tensor information by integrating the intensity and orientation features into a hierarchical matching framework. The intensity features are derived from eigen value based measures that characterize the tensor in terms of its different shape properties, such as, prolateness, oblateness, and sphericity of the tensor. Local spatial distributions of the prolate, oblate, and spherical geometry are used to create an attribute vector called the geometric/intensity feature for matching. The orientation features are the orientation histograms computed from the eigenvectors. These intensity and orientation features are incorporated into a hierarchical deformable registration framework to develop a deformable registration algorithm for DT images. Using orientation features improves the matching of the white matter fiber tracts by taking into account the underlying fiber orientation information. Extensive experiments on simulated and real brain DT data show promising results that makes DROID potentially useful for subsequent group-based analysis of DT images to identify disease-induced and developmental changes in a population. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 99,107, 2010 [source] Does compression affect image retrieval performance?INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2-3 2008Gerald Schaefer Abstract Image retrieval and image compression are both fields of intensive research. As lossy image compression degrades the visual quality of images and hence changes the actual pixel values of an image, low level image retrieval descriptors which are based on statistical properties of pixel values will change, too. In this article we investigate how image compression affects the performance of low-level colour descriptors. Several image retrieval algorithms are evaluated on a speciated image database compressed at different image quality levels. Extensive experiments reveal that while distribution-based colour descriptors are fairly stable with respect to image compression a drop in retrieval performance can nevertheless be observed for JPEG compressed images. On the other hand, after application of JPEG2000 compression only a negligible performance drop is observed even at high compression ratios. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 101,112, 2008 [source] Face recognition based on face-specific subspaceINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2003Shiguang Shan Abstract In this article, we present an individual appearance model based method, named face-specific subspace (FSS), for recognizing human faces under variation in lighting, expression, and viewpoint. This method derives from the traditional Eigenface but differs from it in essence. In Eigenface, each face image is represented as a point in a low-dimensional face subspace shared by all faces; however, the experiments conducted show one of the demerits of such a strategy: it fails to accurately represent the most discriminanting features of a specific face. Therefore, we propose to model each face with one individual face subspace, named Face-Specific Subspace. Distance from the face-specific subspace, that is, the reconstruction error, is then exploited as the similarity measurement for identification. Furthermore, to enable the proposed approach to solve the single example problem, a technique to derive multisamples from one single example is further developed. Extensive experiments on several academic databases show that our method significantly outperforms Eigenface and template matching, which intensively indicates its robustness under variation in illumination, expression, and viewpoint. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13: 23,32, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10047 [source] Context-based generic cross-lingual retrieval of documents and automated summariesJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 2 2005Wai Lam We develop a context-based generic cross-lingual retrieval model that can deal with different language pairs. Our model considers contexts in the query translation process. Contexts in the query as well as in the documents based on co-occurrence statistics from different granularity of passages are exploited. We also investigate cross-lingual retrieval of automatic generic summaries. We have implemented our model for two different cross-lingual settings, namely, retrieving Chinese documents from English queries as well as retrieving English documents from Chinese queries. Extensive experiments have been conducted on a large-scale parallel corpus enabling studies on retrieval performance for two different cross-lingual settings of full-length documents as well as automated summaries. [source] Optimizing image matches via a verification modelINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 11 2010Jimmy Addison Lee In the literature, we have seen a boom in wide-baseline matching approaches proposed for locating correspondences between images. However, wrong correspondences or the so-called outliers are still rather inevitable, especially in urban environments with the presence of repetitive structures, and/or a large dissimilarity in viewpoints. In this paper, we propose a verification model to optimize the image matching results by significantly reducing the number of outliers. Several geometric and appearance-based measurements are exploited, and conditional probability is used to compute the probability of each true correspondence. The model is validated by extensive experiments on images from the ZuBud database, which are taken in different weather conditions, seasons, and with different cameras. It is also demonstrated on a real-time application of an image-based navigation system. © 2010 Wiley Periodicals, Inc. [source] Personalized recommendation with adaptive mixture of markov modelsJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 12 2007Yang Liu With more and more information available on the Internet, the task of making personalized recommendations to assist the user's navigation has become increasingly important. Considering there might be millions of users with different backgrounds accessing a Web site everyday, it is infeasible to build a separate recommendation system for each user. To address this problem, clustering techniques can first be employed to discover user groups. Then, user navigation patterns for each group can be discovered, to allow the adaptation of a Web site to the interest of each individual group. In this paper, we propose to model user access sequences as stochastic processes, and a mixture of Markov models based approach is taken to cluster users and to capture the sequential relationships inherent in user access histories. Several important issues that arise in constructing the Markov models are also addressed. The first issue lies in the complexity of the mixture of Markov models. To improve the efficiency of building/maintaining the mixture of Markov models, we develop a lightweight adapt-ive algorithm to update the model parameters without recomputing model parameters from scratch. The second issue concerns the proper selection of training data for building the mixture of Markov models. We investigate two different training data selection strategies and perform extensive experiments to compare their effectiveness on a real dataset that is generated by a Web-based knowledge management system, Livelink. [source] Direct Measurements of Instantaneous Solid Flux in a CFB Riser using a Novel Multifunctional Optical Fiber ProbeCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 4 2009S. Ye Abstract With a novel optical fiber probe that can measure instantaneous local particle velocity and solid concentration simultaneously, extensive experiments were conducted to study transient flow structures in a 15.1-m long circulating fluidized bed (CFB) riser of 100,mm in diameter. This study analyzed the radial and axial distributions of solid concentration, particle velocity, and their variations with nine operating conditions and at six axial levels. Instantaneous local solid concentration and particle velocity were found to be well correlated at most of the radial positions. The detailed time evolution, axial and radial distribution of instantaneous solid flux, and the variation of solid flux with operating conditions were also investigated. The radial solid flux profile showed a flat shape with a maximum at near wall area under most operating conditions. The instantaneous solid flux was found to have a strong fluctuation at a radial position of r/R,=,0.8 ~ 0.9. [source] | ||||||||||