Entity Ranking on Graphs: Studies on Expert Finding

Todays web search engines try to offer services for finding various information in addition to simple web pages, like showing locations or answering simple fact queries. Understanding the association of named entities and documents is one of the key steps towards such semantic search tasks. This paper addresses the ranking of entities and models it in a graph-based relevance propagation framework. In particular we study the problem of expert finding as an example of an entity ranking task. Entity containment graphs are introduced that represent the relationship between text fragments on the one hand and their contained entities on the other hand. The paper shows how these graphs can be used to propagate relevance information from the pre-ranked text fragments to their entities. We use this propagation framework to model existing approaches to expert finding based on the entity's indegree and extend them by recursive relevance propagation based on a probabilistic random walk over the entity containment graphs. Experiments on the TREC expert search task compare the retrieval performance of the different graph and propagation models

Book Review: Paediatric Trauma and Child Abuse

No Abstract. South African Medical Journal Vol. 98 (3) 2008: pp. 192-19

PFTijah: text search in an XML database system

This paper introduces the PFTijah system, a text search system that is integrated with an XML/XQuery database management system. We present examples of its use, we explain some of the system internals, and discuss plans for future work. PFTijah is part of the open source release of MonetDB/XQuery

Sound ranking algorithms for XML search

Ranking algorithms for XML should reflect the actual combined content and structure constraints of queries, while at the same time producing equal rankings for queries that are semantically equal. Ranking algorithms that produce different rankings for queries that are semantically equal are easily detected by tests on large databases: We call such algorithms not sound. We report the behavior of different approaches to ranking content-and-structure queries on pairs of queries for which we expect equal ranking results from the query semantics. We show that most of these approaches are not sound. Of the remaining approaches, only 3 adhere to the W3C XQuery Full-Text standard

The Hvar survey for roAp stars: II. Final results (Research Note)

The 60 known rapidly oscillating Ap (roAp) stars are excellent laboratories to test pulsation models in the presence of stellar magnetic fields. Our survey is dedicated to search for new group members in the Northern Hemisphere. We attempt to increase the number of known chemically peculiar stars that are known to be pulsationally unstable. About 40 h of new CCD photometric data of 21 roAp candidates, observed at the 1m Austrian-Croatian Telescope (Hvar Observatory) are presented. We carefully analysed these to search for pulsations in the frequency range of up to 10mHz. No new roAp star was detected among the observed targets. The distribution of the upper limits for roAp-like variations is similar to that of previoius similar efforts using photomultipliers and comparable telescope sizes. In addition to photometric observations, we need to consolidate spectroscopic information to select suitable targets.Comment: 8 pages, 5 figures, accepted by Astronomy & Astrophysic

Medical consent for a minor – an alternative proposal

No Abstract. South African Medical Journal Vol. 96(6) 2006: 505-50

Cervical lymph node biopsy - watch the nerves!

Experience with the delayed diagnosis and severe consequences of accessory nerve injury following cervical gland lymph node biopsy prompted us to survey the practice of South African paediatric surgeons and to ascertain the incidence of accessory nerve injury. Cervical lymph gland biopsies are often performed for diagnostic and therapeutic purposes and although spinal accessory nerve (SAN) injury seldom occurs, it remains a significant injury. The operation is relatively minor and cervical glands are commonly biopsied/removed in South Africa by junior doctors, registrars and general practitioners. The operation is often performed as a day case under suboptimal circumstances, despite the fact that it is common knowledge that posterior triangle nodular biopsy carries the risk of iatrogenic damage to the accessory nerve