A web page may be relevant to multiple topics; even when nominally on a single topic, the page may attract attention (and thus links) from multiple communities. Instead of indiscriminately summing the authority provided by all pages, we decompose a web page into separate subnodes with respect to each community pointing to it. By considering the relevance of these communities, we are able to better model the query-specific reputation for each potential result. We apply a total of 125 queries to the TREC .GOV dataset to demonstrate how the use of community relevance can improve ranking performance.

The Web today includes many pages intended to deceive search engines, and attain an unwarranted result ranking. Since the links among web pages are used to calculate authority, ranking systems would benefit from knowing which pages contain content to be trusted and which do not. We propose and compare various trust propagation methods to estimate the trustworthiness of each page. We find that a non-trust-preserving propagation method is able to achieve close to a fifty percent improvement over TrustRank in separating spam from non-spam pages.

This work proposes a novel cautious surfer to incorporate trust into the process of calculating authority for web pages. We evaluate a total of sixty queries over two large, real-world datasets to demonstrate that incorporating trust can improve PageRank's performance.

By supplying different versions of a web page to search engines and to browsers, a content provider attempts to cloak the real content from the view of the search engine. Semantic cloaking refers to differences in meaning between pages which have the effect of deceiving search engine ranking algorithms. In this paper, we propose an automated two-step method to detect semantic cloaking pages based on different copies of the same page downloaded by a web crawler and a web browser. The first step is a filtering step, which generates a candidate list of semantic cloaking pages. In the second step, a classifier is used to detect semantic cloaking pages from the candidates generated by the filtering step. Experiments on manually labeled data sets show that we can generate a classifier with a precision of 93% and a recall of 85%. We apply our approach to links from the dmoz Open Directory Project and estimate that more than 50,000 of these pages employ semantic cloaking.

Web spam is behavior that attempts to deceive search engine ranking algorithms. TrustRank is a recent algorithm that can combat web spam. However, TrustRank is vulnerable in the sense that the seed set used by TrustRank may not be sufficiently representative to cover well the different topics on the Web. Also, for a given seed set, TrustRank has a bias towards larger communities. We propose the use of topical information to partition the seed set and calculate trust scores for each topic separately to address the above issues. A combination of these trust scores for a page is used to determine its ranking. Experimental results on two large datasets show that our Topical TrustRank has a better performance than TrustRank in demoting spam sites or pages. Compared to TrustRank, our best technique can decrease spam from the top ranked sites by as much as 43.1%.

Service advertisement and discovery are important components for computing in mobile ad hoc network (MANET). In this paper, a lightweight protocol of service advertisement and discovery has been implemented, which is based on a MANET multicast protocol ODMRP (On-Demand Multicast Routing Protocol). In this protocol, service advertisement and discovery information is piggybacked in ODMRP routing control packets. Simulation results of the implementation prove that the implementation workload and resource consumption of the protocol are lightweight.