A pipelined architecture for distributed text query evaluation

Two principal query-evaluation methodologies have been described for cluster-based implementation of distributed information retrieval systems: document partitioning and term partitioning. In a document-partitioned system, each of the processors hosts a subset of the documents in the collection, and executes every query against its local sub-collection. In a term-partitioned system, each of the processors hosts a subset of the inverted lists that make up the index of the collection, and serves them to a central machine as they are required for query evaluation. In this paper we introduce a pipelined query-evaluation methodology, based on a term-partitioned index, in which partially evaluated queries are passed amongst the set of processors that host the query terms. This arrangement retains the disk read benefits of term partitioning, but more effectively shares the computational load. We compare the three methodologies experimentally, and show that term distribution is inefficient and scales poorly. The new pipelined approach offers efficient memory utilization and efficient use of disk accesses, but suffers from problems with load balancing between nodes. Until these problems are resolved, document partitioning remains the preferred method. Alistair Moffat was supported by the Australian Research Council, the ARC Special Research Center for Perceptive and Intelligent Machines in Complex Environments, and the NICTA Victoria Laboratory. William Webber and Justin Zobel were supported by the Australian Research Council. Ricardo Baeza-Yates was supported by Grant P01-029-F from Millennium Initiative of Mideplan, Chile; and by the University of Melbourne as a visiting scholar at the time this project was undertaken.     

International Education and Training at Ecole Nationale des Ponts et Chausées/La Formation a l'international a l'Ecole Nationale des Ponts et Chaussées

The programme of the Département de la Formation Internationale at Ecole Nationale des Ponts et Chausées (ENPC) was created in 1981 to address the ever‐increasing international role of today's engineer in the scientific, economic and social spheres. Each year, 75 ENPC students spend at least 3 months abroad, mainly in Europe. ENPC has double degree programmes in engineering studies with three European partners in Germany and Spain: TU Munich and TU Berlin; Universidad Politécnica de Madrid. Twenty per cent of the student curriculum is devoted to language study; the students are required to study English plus one of the following languages: German, Spanish, Italian, Russian, Japanese or Chinese. French courses for foreign students are also provided. Language teaching aims to provide students not only with the linguistic skills necessary for communication, but also to make them more sensitive to other cultures as well as their own.     

REPORT OF BIBLICAL INSTRUCTORS CONFERENCE*

This article examines the psychoanalytic concepts of object-relations theorist Christopher Bollas, applying them to a view of the Bible as “transformational object.” Emphasizing the connection between psychological process and religious experience, this article suggests that each person's innate ability to choose and use objects is a key factor in their ability to appropriate the Bible for constructive use. By offering religious objects with psychological awareness, religious educators may come to appreciate that silence, empathy, and open-ended lesson plans are important incubators of transformation; and that aggression has a potentially positive role in the healthy development of worship communities.     

Stress sensitivity and reading performance in Spanish: A study with children

This paper investigates the relationship between ability to detect changes in prosody and reading performance in Spanish. Participants were children aged 7–8 years. Their tasks consisted of reading words, reading non‐words, stressing non‐words and reproducing sequences of two, three or four non‐words by pressing the corresponding keys on the computer keyboard. Non‐word sequences were constructed with minimal non‐word pairs differing in a single phoneme (/kúpi/ ‐ /kúti/) or in the stress pattern (/mípa/ ‐ /mipá/). Results showed that performance on phoneme contrast sequences (e.g. /kúpi/ ‐ /kúti/) predicted word reading. In contrast, performance on stress contrast sequences (e.g. /mípa/ ‐ /mipá/) predicted non‐word reading, but only when two‐non‐word sequences were analysed. This suggests that stress sensitivity may be one of the factors related to reading fluency as most errors at reading non‐words consisted of false starts and pauses between syllables. Results also showed that stress sensitivity (scored in two non‐word sequences) predicted stress assignment, and that knowledge of stress rules predicted both word and non‐word reading. This suggests that stress sensitivity may help in learning stress rules, and that knowledge of stress rules is relevant for reading.     

The OECD‐ENSI Project and its Relevance for Teacher Training Concepts in Environmental Education

This article presents an account of the Environment and School Initiatives (ENSI) project. The philosophical basis of the project is outlined, and case studies from within the project provided as a basis for a consideration of some current issues in the field. It is concluded that one of the distinctive features of the ENSI project is its encouragement of praxiological, action research‐based approaches to curriculum and professional development. The case studies of ENSI activities suggest that some of the more conventionally prescribed characteristics such as agreed sets of goals and professional competencies might need to be revisited.     

Applying Tablet‐Based Performance Support Application for Technicians’ Training at the Israeli Air Force: A Case Study

Performance support systems are mechanisms enabling users) productivity while reducing training expenses as support is being delivered in real time, often eliminating the need for costly pre‐performance training. Mobile technologies have created new opportunities for improved performance support systems, especially for tasks performed outside the offi ce. This article describes the fi rst mobile learning and performance support initiative taken by the Israeli Air Force. The project included the development and eff ectiveness pilot study of a learning and performance support application delivered via tablet to helicopter engine technicians. The application provided support videos and illustrations of maintenance routines, thereby enabling learning and practicing at the same time. Pilot study results show high performance levels of application users compared to those applying traditional methods. Results also show that self‐effi cacy levels were not aff ected by the successful performance achieved when using the mobile performance support application. Plans to expand mobile support use are also described.