Some Axioms of Weak Determinacy

We consider two-player games of perfect information of length some cardinal $\kappa$. It is well-known that for $\kappa \geq \omega_1$ the full axiom of determinacy for these games fails, thus we investigate three weaker forms of it. We obtain the measurability of $\kappa^{+}$ under $DC_{\kappa}$-the axiom of dependent choices generalized to $\kappa$. We generalize the notions of perfect and meager sets and provide characterizations with some special kinds of games. We show that under an additional assumption one of our three axioms follows from the other two

UNIFORM REGULAR ENUMERATIONS

Abstract. In the paper we introduce and study the uniform regular enumerations for arbitrary recursive ordinals. As an application of the technique we obtain a uniform generalization of a theorem of Ash and a characterization of a class of uniform operators on transfinite sequences of sets of natural numbers. 1

Classifying queries submitted to a vertical search engine

We propose and motivate a scheme for classifying queries submitted to a people search engine. We specify a number of features for automatically classifying people queries into the proposed classes and examine the effectiveness of these features. Our main finding is that classification is feasible and that using information from past searches, clickouts and news sources is important

Rijke. People searching for people: Analysis of a people search engine log

Recent years show an increasing interest in vertical search: searching within a particular type of information. Understanding what people search for in these “verticals ” gives direction to research and provides pointers for the search engines themselves. In this paper we analyze the search logs of one particular vertical: people search engines. Based on an extensive analysis of the logs of a search engine geared towards finding people, we propose a classification scheme for people search at three levels: (a) queries, (b) sessions, and (c) users. For queries, we identify three types, (i) event-based high-profile queries (people that become “popular ” because of an event happening), (ii) regular high-profile queries (celebrities), and (iii) low-profile queries (other, less-known people). We present experiments on automatic classification of queries. On the session level, we observe five types: (i) family sessions (users looking for relatives), (ii) event sessions (querying the main players of an event), (iii) spotting sessions (trying to “spot ” different celebrities online), (iv) polymerous sessions (sessions without a clear relation between queries), and (v) repetitive sessions (query refinement and copying). Finally, for users we identify four types: (i) monitors, (ii) spotters, (iii) followers, and (iv) polymers. Our findings not only offer insight into search behavior in people search engines, but they are also useful to identify future research directions and to provide pointers for search engine improvements