An effective, low-cost measure of semantic relatedness obtained from Wikipedia links

This paper describes a new technique for obtaining measures of semantic relatedness. Like other recent approaches, it uses Wikipedia to provide structured world knowledge about the terms of interest. Out approach is unique in that it does so using the hyperlink structure of Wikipedia rather than its category hierarchy or textual content. Evaluation with manually defined measures of semantic relatedness reveals this to be an effective compromise between the ease of computation of the former approach and the accuracy of the latter

Comparison of hydroxyl radical formation in aqueous solutions at different ultrasound frequencies and powers using the salicylic acid dosimeter

Ultrasonic frequencies of 20 kHz, 382 kHz, 584 kHz, 862 kHz (and 998 kHz) have been compared with regard to energy output and hydroxyl radical formation utilising the salicylic acid dosimeter. The 862 kHz frequency inputs 6 times the number of Watts into water, as measured by calorimetry, with the other frequencies having roughly the same value under very similar conditions. A plausible explanation involving acoustic fountain formation is proposed although enhanced coupling between this frequency and water cannot be discounted. Using the salicylic acid dosimeter and inputting virtually the same Wattages it is established that 862 kHz is around 10% more efficient at generating hydroxyl radicals than the 382 kHz but both of these are far more effective than the other frequencies. Also, it is found that as temperature increases to 42 °C then the total dihydroxybenzoic acid (Total DHBA) produced is virtually identical for 382 kHz and 862 kHz, though 582 kHz is substantially lower, when the power levels are set at approximately 9 W for all systems. An equivalent power level of 9 W could not be obtained for the 998 kHz transducer so a direct comparison could not be made in this instance. These results have implications for the optimum frequencies chosen for both Advanced Oxidation Processes (AOPs) and organic synthesis augmented by ultrasound

The reliability and validity of a field hockey skill test

High test retest reliability is essential in tests used for both scientific research and to monitor athletic performance. Thirty-nine (20 male and 19 female) well-trained university field hockey players volunteered to participate in the study. The reliability of the in house designed test was determined by repeating the test (3-14 days later) following full familiarisation. The validity was assessed by comparing coaches ranks of players with ranked performance on the skill test. The mean difference and confidence limits in overall skill test performance was 0.0 ± 1.0% and the standard error (confidence limits) was 2.1% (1.7 to 2.8%). The mean difference and confidence limits for the ‘decision making’ time was 0.0 ± 1.0% and the standard error (confidence limits) was 4.5% (3.6 to 6.2%). The validity correlation (Pearson) was r = 0.83 and r= 0.73 for female players and r = 0.61 and r = 0.70 for male players for overall time and ‘decision making’ time respectively. We conclude that the field hockey skill test is a reliable measure of skill performance and that it is valid as a predictor of coach assessed hockey performance, but the validity is greater for female players

Mining Domain-Specific Thesauri from Wikipedia: A case study

Domain-specific thesauri are high-cost, high-maintenance, high-value knowledge structures. We show how the classic thesaurus structure of terms and links can be mined automatically from Wikipedia. In a comparison with a professional thesaurus for agriculture we find that Wikipedia contains a substantial proportion of its concepts and semantic relations; furthermore it has impressive coverage of contemporary documents in the domain. Thesauri derived using our techniques capitalize on existing public efforts and tend to reflect contemporary language usage better than their costly, painstakingly-constructed manual counterparts

Horizontal-axis tidal turbine blade loading for multi-frequency oscillatory motion

This paper presents results from an experimental study which analysed the hydrodynamic response of the out-of-plane blade root bending moment for a horizontal-axis turbine exposed to multi-frequency oscillatory motion. Estimates of the amplitude and phase agree well with those for single frequency oscillatory motion, which suggests that a model based on the principles of linear superposition is applicable. When minor flow separation is experienced, linear superposition is likely to offer conservative estimates. The findings are likely to be of interest to designers of turbines deployed in tidal streams, rivers or canals, and who are seeking low computational approaches for assessing the dynamic blade loads

A competitive environment for exploratory query expansion

Most information workers query digital libraries many times a day. Yet people have little opportunity to hone their skills in a controlled environment, or compare their performance with others in an objective way. Conversely, although search engine logs record how users evolve queries, they lack crucial information about the user's intent. This paper describes an environment for exploratory query expansion that pits users against each other and lets them compete, and practice, in their own time and on their own workstation. The system captures query evolution behavior on predetermined information-seeking tasks. It is publicly available, and the code is open source so that others can set up their own competitive environments

Extracting corpus specific knowledge bases from Wikipedia

Thesauri are useful knowledge structures for assisting information retrieval. Yet their production is labor-intensive, and few domains have comprehensive thesauri that cover domain-specific concepts and contemporary usage. One approach, which has been attempted without much success for decades, is to seek statistical natural language processing algorithms that work on free text. Instead, we propose to replace costly professional indexers with thousands of dedicated amateur volunteers--namely, those that are producing Wikipedia. This vast, open encyclopedia represents a rich tapestry of topics and semantics and a huge investment of human effort and judgment. We show how this can be directly exploited to provide WikiSauri: manually-defined yet inexpensive thesaurus structures that are specifically tailored to expose the topics, terminology and semantics of individual document collections. We also offer concrete evidence of the effectiveness of WikiSauri for assisting information retrieval

Clustering documents with active learning using Wikipedia

Wikipedia has been applied as a background knowledge base to various text mining problems, but very few attempts have been made to utilize it for document clustering. In this paper we propose to exploit the semantic knowledge in Wikipedia for clustering, enabling the automatic grouping of documents with similar themes. Although clustering is intrinsically unsupervised, recent research has shown that incorporating supervision improves clustering performance, even when limited supervision is provided. The approach presented in this paper applies supervision using active learning. We first utilize Wikipedia to create a concept-based representation of a text document, with each concept associated to a Wikipedia article. We then exploit the semantic relatedness between Wikipedia concepts to find pair-wise instance-level constraints for supervised clustering, guiding clustering towards the direction indicated by the constraints. We test our approach on three standard text document datasets. Empirical results show that our basic document representation strategy yields comparable performance to previous attempts; and adding constraints improves clustering performance further by up to 20%