Search

Current web search engines retrieve relevant results only based on the latest content of web pages stored in their indices despite the fact that many web resources update frequently. We explore possible techniques and data sources for improving web search result ranking using web page historical content change. We compare web pages with previous versions and separately model texts and relevance signals in the newly added, retained, and removed parts. We particularly examine the Internet Archive, the largest web archiving service thus far, for its effectiveness in improving web search performance. We experiment with a few possible retrieval techniques, including language modeling approaches using refined document and query representations built based on comparing current web pages to previous versions and Learning-to-rank methods for combining relevance features in different versions of web pages. Experimental results on two large-scale retrieval datasets (ClueWeb09 and ClueWeb12) suggest it is promising to use web page content change history to improve web search performance. However, it is worth mentioning that the actual effectiveness at this moment is affected by the practical coverage of the Internet Archive and the amount of regularly-changing resources among the relevant information related to search queries. Our work is the first step towards a promising area combining web search and web archiving, and discloses new opportunities for commercial search engines and web archiving services.

Current web search engines retrieve relevant results only based on the latest content of web pages stored in their indices despite the fact that many web resources update frequently. We explore possible techniques and data sources for improving web search result ranking using web page historical content change. We compare web pages with previous versions and separately model texts and relevance signals in the newly added, retained, and removed parts. We particularly examine the Internet Archive, the largest web archiving service thus far, for its effectiveness in improving web search performance. We experiment with a few possible retrieval techniques, including language modeling approaches using refined document and query representations built based on comparing current web pages to previous versions and Learning-to-rank methods for combining relevance features in different versions of web pages. Experimental results on two large-scale retrieval datasets (ClueWeb09 and ClueWeb12) suggest it is promising to use web page content change history to improve web search performance. However, it is worth mentioning that the actual effectiveness at this moment is affected by the practical coverage of the Internet Archive and the amount of regularly-changing resources among the relevant information related to search queries. Our work is the first step towards a promising area combining web search and web archiving, and discloses new opportunities for commercial search engines and web archiving services.

The goal of the GETAR project is to devise interactive, integrated, digital library/archive systems coupled with linked and expert-curated web-page/tweet collections. In this class team project, the URL analysis system we designed takes a tweet collection as input and uses Hadoop and Spark to extract short URLs. We expanded them, fetched their web-page with the corresponding long URL, and applied the WayBack CDX Server API to attempt to restore the most likely snapshot. Then, we conducted a systematic URL analysis, for different types of events. We analyzed nine tweet collections in four categories: Nature, Health, Man-made, and Particular Event. Each tweet collection contains the tweet content from 2013-2017 that related to a specific keyword. For each collection, we analyzed several characteristics in URLs, top-k domains of the URLs, URL retrieve rate, and URL retrieve rate boosted by using the WayBack CDX Server API. We provided several visualizations of the results we analyzed from these nine tweet collections. We have refined this project so that it is easy to build on; see section 5 (Developer Manual) in the final report for details.

Expanded frequency spectrum communications, hereafter referred to as 'expanded communications' is a very important technology in modern communications. It features good resistance to interference and good security capabilities. In the area of rangefinding, it is able to improve the rangefinding accuracy because rangefinding accuracy is related to th expanded band. In use, it offers code portion multiple addresses; multiple users can use a channel jointly. SAW devices have many applications in a communications system. This paper is intended chiefly to describe the application of the SAW- MSK signal modulator/generator and the SAW convoluter in an expended communications system, and to report on several actual results. In today's world, there are many forms of expanded communication. MSK (minimum frequency drift key control) signals are one kind of binary digit modulating signal whose excellent functions have attracted attention. This is because, in comparison with the frequency used PSK signals, they not only possess the features of a constant amplitude and continuous phase, but they also have a relatively concentrated energy spectrum. Radiated power outside the band rolls down quickly, and the crossover interference between the frequency channels is small. Chinese translations, Reprints., Trans. of Yingyong Shenyxue (China) n2 p1-5 1988.