14756022
Speckle-noise reduction via "rotated elliptical-thresholding" in an homomorphic complex-wavelet domain
Speckle noise has been found to rotate an image's homomorphic elliptically distributed complex-wavelet coefficients. This work proposes a counter-rotation of these complex-wavelet coefficients as a means of mitigating speckle noise using principle component analysis. Simulations suggest that the proposed denoising technique offers superior visual quality, though its signal-to-mean-square-error ratio (S/MSE) is numerically comparable to the improvement obtained in customary median filtering and adaptive Wiener filtering.
26459571
Geolocation for partially polarized electromagnetic sources using multiple sparsely and uniformly spaced "spatially stretched vector sensors"
A new angle-of-arrival estimation technique is developed using an array of "spatially stretched electromagnetic vector sensors" (each of which comprises a dipole triad plus a spatially displaced loop triad) for completely polarized, partially polarized and/or unpolarized incident signals. A dipole (loop) triad is composed of three identical, spatially co-located but orthogonally oriented electrically short dipoles (magnetically small loops) distinctly measuring all three electric-field (magnetic-field) components of the (possibly) partially polarized incident wave-field. The vector cross-product direction finding approach is herein generalized to allow: (1) any arbitrary displacement between the dipole triad and the loop triad comprising the six-component electromagnetic vector sensor, thereby reducing the adverse effects of inter-antenna mutual coupling, (2) any unknown temporal phase delay between the dipole triad and the loop triad (a common situation in electromagnetics), (3) the incident electromagnetic signals to be arbitrarily partially polarized or unpolarized. Simulations demonstrate the efficacy of this new technique.
16104056
Performance analysis and design of a logic simulation machine
The high costs associated with logic simulation of large VLSI circuits has led to the need for new computer architectures tailored to the simulation task. Such architectures have the potential for significant speed-ups over software-based logic simulators executing on standard sequential computers. This paper presents a model of one class of multiprocessor simulation architectures and compares the performance of some of these machines using data obtained from simulations of VLSI circuits. In addition, we discuss the implications of our results on machine design and examine the sensitivity of the model to variations in circuit characteristics.
9524579
Epipolar geometry from profiles under circular motion
Addresses the problem of motion estimation from profiles (apparent contours) of an object rotating on a turntable in front of a single camera. A practical and accurate technique for solving this problem from profiles alone is developed. It is precise enough to reconstruct the shape of the object. No correspondences between points or lines are necessary. Symmetry of the surface of revolution swept out by the rotating object is exploited to obtain the image of the rotation axis and the homography relating epipolar lines in two views robustly and elegantly. These, together with geometric constraints for images of rotating objects, are used to obtain first the image of the horizon, which is the projection of the plane that contains the camera centers, and then the epipoles, thus fully determining the epipolar geometry of the image sequence. The estimation of this geometry by this sequential approach avoids many of the problems found in other algorithms. The search for the epipoles, by far the most critical step, is carried out as a simple 1D optimization. Parameter initialization is trivial and completely automatic at all stages. After the estimation of the epipolar geometry, the Euclidean motion is recovered using the fixed intrinsic parameters of the camera obtained either from a calibration grid or from self-calibration techniques. Finally, the spinning object is reconstructed from its profiles using the motion estimated in the previous stage. Results from real data are presented, demonstrating the efficiency and usefulness of the proposed methods.
15569102
Improving document clustering by utilizing meta-data
In this paper, we examine how to improve the precision and recall of document clustering by utilizing meta-data. We use meta-data through NewsML tags to assist clustering and show that this approach is effective through experiments on sample news data. Experimental result shows that clustering using NewsML could improve average recall and precision over the same without using NewsML by about 10%. Our algorithm facilitates effective e-business for the news media and publishing industry to empower e-business.
30930498
Chinese document indexing based on a new partitioned signature file: Model and evaluation
In this article we investigate the use of signature files in Chinese information retrieval system and propose a new partitioning method for Chinese signature file based on the characteristic of Chinese words. Our partitioning method, called Partitioned Signature File for Chinese (PSFC), offers faster search efficiency than the traditional single signature file approach. We devise a general scheme for controlling the trade-off between the false drop and storage overhead while maintaining the search space reduction in PSFC. An analytical study is presented to support the claims of our method. We also propose two new hashing methods for Chinese signature files so that the signature file will be more suitable for dynamic environment while the retrieval performance is maintained. Furthermore, we have implemented PSFC and the new hashing methods, and we evaluated them using a large-scale real-world Chinese document corpus, namely, the TREC-5 (Text REtrieval Conference) Chinese collection. The experimental results confirm the features of PSFC and demonstrate its superiority over the traditional single signature file method.
14387450
Adoption challenges in migrating to web services
This paper outlines some of the challenges inherent in migrating to Web services. Technology adoption is a continual challenge for both tool developers and enterprise users. Web services are a prime example of a red-hot technology that is fraught with adoption issues. Part of the problem is separating marketing hype from business reality. Web services are network-accessible interfaces to application functionality. They are built using Internet technologies such as XML and standard protocols such as SOAP. The adoption issues related to Web services are complex and multifaceted. For example, determining whether this technology is a fundamental advance, rather than something old under a new name, requires technical depth, business acumen, and considerable historical knowledge of past claims. A model problem from the health care industry is used to illustrate some of the adoption issues that arise in migrating to Web services.