results, we propose computing a set of PageRank vectors, biased using a set of representative topics, to capture more accurately the notion of importance with respect to a particular topic. By using these (precomputed) biased PageRank vectors to generate query-specific importance scores for pages at query

Scientists need new tools to explore and browse large collections of scholarly literature. Thanks to organizations such as JSTOR, which scan and index the original bound archives of many journals, modern scientists can search digital libraries spanning hundreds of years. A scientist, suddenly

We examine the frequency of price changes for 350 categories of goods and services covering about 70 % of consumer spending, based on unpublished data from the BLS for 1995 to 1997. Compared with previous studies we find much more frequent price changes, with half of goods' prices lasting less than 4.3 months. Even excluding the role of temporary price cuts (sales), we find that half of goods' prices last 5.5 months or less. The frequency of price changes differs dramatically across categories. We exploit this variation to ask how inflation for "flexible-price goods" (goods with frequent changes in individual prices) differs from inflation for "sticky-price goods" (those displaying infrequent price changes). Compared to the predictions of popular sticky price models, actual inflation rates are far more volatile and transient, particularly for sticky-price goods.

that are relevant to a pre-defined set of topics. The topics are specified not using keywords, but using exemplary documents. Rather than collecting and indexing all accessible Web documents to be able to answer all possible ad-hoc queries, a focused crawler analyzes its crawl boundary to find the links

Collision avoidance is an important topic in multi-robot systems. Existing multi-robot pathfinding approaches ignore sideswipe collisions among robots (i.e., only consider the collision which two agents try to occupy the same node during the same time-step) [1, 3, 4], and allow diagonal move

This essay provides a perspective on the trend towards integrating psychology into economics. Some topics are discussed, and arguments are provided for why movement towards greater psychological realism in economics will improve mainstream economics.

which can be used in proofs of the properties of computer programs. Examples are given of such axioms and rules, and a formal proof of a simple theorem is displayed. Finally, it is argued that important advantages, both theoretical and prac-tical, may follow from a pursuance of these topics.

This paper provides an elementary, non-technical, survey of auction theory, by introducing and describing some of the critical papers in the subject. (The most important of these are reproduced in a companion book, The Economic Theory of Auctions, Paul Klemperer (ed.), Edward Elgar (pub

Intentions, an integral part of the mental state of an agent, play an important role in

The proliferation of topic hierarchies for text documents has resulted in a need for tools that automatically classify new documents within such hierarchies. Existing classification schemes which ignore the hierarchical structure and treat the topics as separate classes are often inadequate in text