The effects of topic familiarity on user search behavior in question answering systems

This paper reports on experiments that attempt to characterize the relationship between users and their knowledge of the search topic in a Question Answering (QA) system. It also investigates user search behavior with respect to the length of answers presented by a QA system. Two lengths of answers were compared; snippets (one to two sentences of text) and exact answers. A user test was conducted, 92 factoid questions were judged by 44 participants, to explore the participants’ preferences, feelings and opinions about QA system tasks. The conclusions drawn from the results were that participants preferred and obtained higher accuracy in finding answers from the snippets set. However, accuracy varied according to users’ topic familiarity; users were only substantially helped by the wider context of a snippet if they were already familiar with the topic of the question, without such familiarity, users were about as accurate at locating answers from the snippets as they were in exact set

The exotic invasive plant Vincetoxicum rossicum is a strong competitor even outside its current realized climatic temperature range

Dog-strangling vine (Vincetoxicum rossicum) is an exotic plant originating from Central and Eastern Europe that is becoming increasingly invasive in southern Ontario, Canada. Once established, it successfully displaces local native plant species but mechanisms behind this plant’s high competitive ability are not fully understood. It is unknown whether cooler temperatures will limit the range expansion of V. rossicum, which has demonstrated high tolerance for other environmental variables such as light and soil moisture. Furthermore, if V. rossicum can establish outside its current climatic limit it is unknown whether competition with native species can significantly contribute to reduce fitness and slow down invasion. We conducted an experiment to test the potential of V. rossicum to spread into northern areas of Ontario using a set of growth chambers to simulate southern and northern Ontario climatic temperature regimes. We also tested plant-plant competition by growing V. rossicum in pots with a highly abundant native species, Solidago canadensis, and comparing growth responses to plants grown alone. We found that the fitness of V. rossicum was not affected by the cooler climate despite a delay in reproductive phenology. Growing V. rossicum with S. canadensis caused a significant reduction in seedpod biomass of V. rossicum. However, we did not detect a temperature x competition interaction in spite of evidence for adaptation of S. canadensis to cooler temperature conditions. We conclude that the spread of V. rossicum north within the tested range is unlikely to be limited by climatic temperature but competition with an abundant native species may contribute to slow it down

The Birmingham-CfA cluster scaling project - II. Mass composition and distribution

We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the deprojected spatial distribution of galaxy luminosity for a subset of this sample, spanning over 2 decades in mass. With this combined X-ray/optical study we examine the scaling properties of the baryons and address the issue of mass-to-light (M/L) ratio in groups and clusters of galaxies. We measure a median mass-to-light ratio of 224 h70 M/L (solar) in the rest frame B_j band, in good agreement with other measurements based on X-ray determined masses. There is no trend in M/L with X-ray temperature and no significant trend for mass to increase faster than luminosity: M \propto \L_{B,j}^{1.08 +/- 0.12}. This implied lack of significant variation in star formation efficiency suggests that gas cooling cannot be greatly enhanced in groups, unless it drops out to form baryonic dark matter. Correspondingly, our results indicate that non-gravitational heating must have played a significant role in establishing the observed departure from self-similarity in low mass systems. The median baryon fraction for our sample is 0.162 h70^{-3/2}, which allows us to place an upper limit on the cosmological matter density, Omega_m <= 0.27 h70^{-1}, in good agreement with the latest results from WMAP. We find evidence of a systematic trend towards higher central density concentration in the coolest haloes, indicative of an early formation epoch and consistent with hierarchical formation models.Comment: 14 pages, 11 figures; published in MNRAS. Corrected mistake in photometric conversion (equation 2): Bj luminosities increased for A2218, N2563 & N5846. Conclusions unchange

The Relationship between IR Effectiveness Measures and User Satisfaction

This paper presents an experimental study of users assessing the quality of Google web search results. In particular we look at how users' satisfaction correlates with the effectiveness of Google as quantified by IR measures such as precision and the suite of Cumulative Gain measures (CG, DCG, NDCG). Results indicate strong correlation between users' satisfaction, CG and precision, moderate correlation with DCG, with perhaps surprisingly negligible correlation with NDCG. The reasons for the low correlation with NDCG are examined

Users' effectiveness and satisfaction for image retrieval

This paper presents results from an initial user study exploring the relationship between system effectiveness as quantified by traditional measures such as precision and recall, and users’ effectiveness and satisfaction of the results. The tasks involve finding images for recall-based tasks. It was concluded that no direct relationship between system effectiveness and users’ performance could be proven (as shown by previous research). People learn to adapt to a system regardless of its effectiveness. This study recommends that a combination of attributes (e.g. system effectiveness, user performance and satisfaction) is a more effective way to evaluate interactive retrieval systems. Results of this study also reveal that users are more concerned with accuracy than coverage of the search results

Keep It Simple Sheffield – a KISS approach to the Arabic track

Sheffield’s participation in the inaugural Arabic cross language track is described here. Our goal was to examine how well one could achieve retrieval of Arabic text with the minimum of resources and adaptation of existing retrieval systems. To this end the public translators used for query translation and the minimal changes to our retrieval system are described. While the effectiveness of our resulting system is not as high as one might desire, it nevertheless provides reasonable performance particularly in the monolingual track: on average, just under four relevant documents were found in the 10 top ranked documents

The Birmingham-CfA cluster scaling project - III: entropy and similarity in galaxy systems

We examine profiles and scaling properties of the entropy of the intergalactic gas in a sample of 66 virialized systems, ranging in mass from single elliptical galaxies to rich clusters, for which we have resolved X-ray temperature profiles. Some of the properties we derive appear to be inconsistent with any of the models put forward to explain the breaking of self-similarity in the baryon content of clusters. In particular, the entropy profiles, scaled to the virial radius, are broadly similar in form across the sample, apart from a normalization factor which differs from the simple self-similar scaling with temperature. Low mass systems do not show the large isentropic cores predicted by preheating models, and the high entropy excesses reported at large radii in groups by Finoguenov et al (2002) are confirmed, and found to extend even to moderately rich clusters. We discuss the implications of these results for the evolutionary history of the hot gas in clusters, and suggest that preheating may affect the entropy of intracluster gas primarily by reducing the density of material accreting into groups and clusters along cosmic filaments.Comment: 13 pages, 8 figures - accepted for publication in MNRA

Morphological variation of Arabic queries

Although it has been shown that in test collection based studies, stemming improves retrieval effectiveness in an information retrieval system, morphological variations of queries searching on the same topic are less well understood. This work examines the broad morphological variation that searchers of an Arabic retrieval system put into their queries. In this study, 15 native Arabic speakers were asked to generate queries, morphological variants of query words were collated across users. Queries composed of either the commonest or rarest variants of each word were submitted to a retrieval system and the effectiveness of the searches was measured. It was found that queries composed of the more popular morphological variants were more likely to retrieve relevant documents that those composed of less popular

Precedence relationship representations of mechanical assembly sequences

Two types of precedence relationship representations for mechanical assembly sequences are presented: precedence relationships between the establishment of one connection between two parts and the establishment of another connection, and precedence relationships between the establishment of one connection and states of the assembly process. Precedence relationship representations have the advantage of being very compact. The problem with these representations was how to guarantee their correctness and completeness. Two theorems are presented each of which leads to the generation of one type of precedence relationship representation guaranteeing its correctness and completeness for a class of assemblies

In-flight damping measurement

A new testing technique is described which can be applied in determining the damping coefficient of the critical vibration modes of an airplane in flight. The damping coefficient can be determined in several different ways from the same data using different features of a modified response curve which implies the possibility of checking one value against the other. The method introduces the effect of sweep rate in the driving system. This effect on the frequency response curve of the critical vibration mode and its various characteristics are used in the determination of damping coefficient. A theoretical examination is made of these characteristics for single degree of freedom systems