Volume 18, Issue 1, January 2013

Comparison of existing open-source tools for Web crawling and indexing of free Music [Full Text]

André Ricardo and Carlos Serrão

Abstract— This paper presents a portrait of existing open-source web crawlers tools that also have an indexing component. The goal is to understand what tool is best suited to crawl and index a large collection of music MP3 files freely available in the Internet. In this study each piece of software is briefly described, with an overview, identification of some users, and their main advantages and disadvantages. In order to better understand the most significant differences between the different tools a resume of features like: programming language in which they are written, the platform used for deployment, the type of index used, database integration, front-end capabilities, existence of a plugin system, MP3 and Adobe Flash (SWF files) parsing support, is presented. Finally the tools were classified according to the prospected collection size, being divided into tools to mirror small collections, medium and large collections with software capable of handling large amounts of data. In conclusion, an assessment on which tools are best suited to handle large collections in a distributed way is made. 

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Accurate Analysis of Waveguide Filters by the Coupled Integral Equations [Full Text]

H. Ghorbaninejad and M. Foroughi

Abstract—In this paper the coupled magnetic field integral equation is applied to accurately determine the frequency response of waveguide band-pass filters in which the irises are closely spaced due to compacting techniques and higher order mode effects are essential in the filter performance. A three-resonator H plane filter is designed and analyzed in which the thickness of irises and coupling effect between them have been considered. To take the effect of higher order modes, a coupled set of magnetic field integral equations (MFIE) is derived and formulated. Finally a set of linear matrix equations are solved using method of moment (MoM) and entire basis functions which results rapid convergence. The usefulness of the proposed method and its performance are verified by designing and simulating a three-resonator H plane equal ripple waveguide band-pass filter. 

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Analytical Analysis of Ray Characteristics Inside the Optical Fiber [Full Text]

Chakresh Kumar, Girish Narah and Aroop Sharma

Abstract-In this paper we obtain solution of the ray equations in a parabolic and elliptical refractive index profile. We studied the various conditions for the suitable propagation of ray inside the fiber. A comparison is also made between the ray propagating in elliptical and parabolic refractive index profile.