8311870
Automatically Determining Semantics for World Wide Web Multimedia Information Retrieval
Search engines are useful because they allow the user to find information of interest from the World Wide Web (WWW). However, most of the popular search engines today are textual; they do not allow the user to find images from the web. For effective retrieval, determining the semantics of the images is essential. In this paper, we describe the problems in determining the semantics of images on the WWW and the approach of AMORE, a WWW search engine that we have developed. AMORE's techniques can be extended to other media like audio and video. We explain how we assign keywords to the images based on HTML pages and the method to determine similar images based on the assigned text. We also discuss some statistics showing the effectiveness of our technique. Finally, we present the visual interface of AMORE with the help of several retrieval scenarios.
2425278
Shuffling a Stacked Deck: The Case for Partially Randomized Ranking of Search Engine Results
In-degree, PageRank, number of visits and other measures of Web page popularity significantly influence the ranking of search results by modern search engines. The assumption is that popularity is closely correlated with quality, a more elusive concept that is difficult to measure directly. Unfortunately, the correlation between popularity and quality is very weak for newly-created pages that have yet to receive many visits and/or in-links. Worse, since discovery of new content is largely done by querying search engines, and because users usually focus their attention on the top few results, newly-created but high-quality pages are effectively "shut out," and it can take a very long time before they become popular.We propose a simple and elegant solution to this problem: the introduction of a controlled amount of randomness into search result ranking methods. Doing so offers new pages a chance to prove their worth, although clearly using too much randomness will degrade result quality and annul any benefits achieved. Hence there is a tradeoff between exploration to estimate the quality of new pages and exploitation of pages already known to be of high quality. We study this tradeoff both analytically and via simulation, in the context of an economic objective function based on aggregate result quality amortized over time. We show that a modest amount of randomness leads to improved search results.
171503
Parallel crawlers
In this paper we study how we can design an effective parallel crawler. As the size of the Web grows, it becomes imperative to parallelize a crawling process, in order to finish downloading pages in a reasonable amount of time. We first propose multiple architectures for a parallel crawler and identify fundamental issues related to parallel crawling. Based on this understanding, we then propose metrics to evaluate a parallel crawler, and compare the proposed architectures using 40 million pages collected from the Web. Our results clarify the relative merits of each architecture and provide a good guideline on when to adopt which architecture.
1713822
A fast regular expression indexing engine
In this paper; we describe the design, architecture, and lessons learned from the implementation of a fast regular-expression indexing engine FREE. FREE uses a prebuilt index to identify the text data units which may contain a matching string and only examines these further. In this way, FREE shows orders of magnitude performance improvement in certain cases over standard regular expression matching systems, such as lex, awk and grep.
1739520
Exploiting Geographical Location Information of Web Pages
Many information resources on the web are relevant primarily to limited geographical communities. For instance, web sites containing information on restaurants, theaters, and apartment rentals are relevant primarily to web users in geographical proximity to these locations. In contrast, other information resources are relevant to a broader geographical community. For instance, an on-line newspaper may be relevant to users across the United States. Unfortunately, the geographical scope of web resources is largely ignored by web search engines. We make the case for identifying and exploiting the geographical location information of web sites so that web search engines can rank resources in a geographically sensitive fashion, in addition to using more traditional information-retrieval strategies. In this paper, we first consider how to compute the geographical location of web pages. Subsequently, we consider how to exploit such information in one specific "proof-of-concept" application we implemented in JAVA, and discuss other examples as well.
516682
Efficient Crawling Through URL Ordering
In this paper we study in what order a crawler should visit the URLs it has seen, in order to obtain more "important" pages first. Obtaining important pages rapidly can be very useful when a crawler cannot visit the entire Web in a reasonable amount of time. We define several importance metrics, ordering schemes, and performance evaluation measures for this problem. We also experimentally evaluate the ordering schemes on the Stanford University Web. Our results show that a crawler with a good ordering scheme can obtain important pages significantly faster than one without.
36016648
Echo Watermarking in Sub-band Domain
Echo hiding is a method for embedding information, called watermark, into an audio signal. In general, echo hiding is processed in the time domain by convolving audio signal with echo kernel, without any consideration of the frequency characteristics. In this paper, we propose an echo hiding technique, which inserts echo into sub-band signal so as to take account into the frequency characteristics. The proposed echo hiding enables to embed high-energy echo, while minimizing the host audio quality distortion. In addition, the proposed allows increasing watermark capacity, since it is possible to embed simultaneously some watermark bits into different sub-band signals. The simulation results show that the proposed is more effective than the conventional echo hiding, in terms of watermark capacity and robustness against various attacks.
26782414
The Semantics of a Functional Logic Language with Input Mode
43684392
Wavelet Analysis Based Blind Watermarking for 3-D Surface Meshes
As most previous wavelet analysis based 3-D mesh watermarking methods embed the watermark information into wavelet coefficients arranged in a certain order, they have not been used as blind schemes since the connectivity information must be exactly known in the watermark extraction process. In this paper, we propose a blind watermarking method based on wavelet analysis for 3-D mesh model. Two new techniques are introduced. One is to exploit the statistical features of scale coefficients on an approximation (low resolution) level for watermark embedding. Another is to extract the hidden watermark, not from the same resolution level as used in embedding process, but directly from the spatial domain. As the proposed watermark detection does not require the wavelet analysis, any pre-processing such as registration and re-sampling, is not needed. These techniques allow to detect the watermark without referring to the original meshes. In addition, the proposed are applicable directly to irregular meshes by using irregular wavelet analysis. Through simulations, we prove that our method is fairly robust against various attacks including topological ones.
30800683
An optimal signal design for band-limited asynchronous DS-CDMA Communications
An optimal signal design for band-limited, asynchronous, direct-sequence code-division multiple-access (DS-CDMA) communications with aperiodic random spreading sequences and a conventional matched filter receiver is considered in an additive white Gaussian noise (AWGN) channel. With bandwidth defined in the strict sense, two optimization problems are solved under finite bandwidth and zero interchip interference constraints. First, a chip waveform optimization is performed given the system bandwidth, the data symbol transmission rate, and the processing gain. A technique to characterize a band-limited chip waveform with a finite number of parameters is developed, and it is used to derive optimum chip waveforms which minimize the effect of multiple-access interference (MAI) for any energy and delay profile of users. Next, a joint optimization of the processing gain and the chip waveform is performed, given the system bandwidth and the data symbol transmission rate. A sufficient condition for a system to have lower average probability of bit error for any energy profile is found, and it is used to derive some design strategies. It is shown that the flat spectrum pulse with the processing gain leading to zero excess bandwidth results in the minimum average probability of bit error. Design examples and numerical results are also provided.
39501622
A logic programming approach to hybrid knowledge representation
A new hybrid system called Sphinx is presented which combines classification-based reasoning with logic programming technique. It consists of two major components: a terminological component and an assertional one. The former uses a frame-based knowledge representation scheme based on classification and the latter is a theorem prover based on Horn logic. The assertional component can also handle a first-order query language and wh-questions. A new knowledge base maintenance mechanism based on the negation as failure inference rule enables Sphinx to support incremental assertions and retractions. In addition, Sphinx provides explanation capability to help the user in developing and debugging knowledge bases.