2,435 research outputs found

    RANDOM EVOLUTIONS, MARKOV CHAINS, AND SYSTEMS OF PARTIAL DIFFERENTIAL EQUATIONS

    Full text link

    The TREC 2004 genomics track categorization task: classifying full text biomedical documents

    Get PDF
    BACKGROUND: The TREC 2004 Genomics Track focused on applying information retrieval and text mining techniques to improve the use of genomic information in biomedicine. The Genomics Track consisted of two main tasks, ad hoc retrieval and document categorization. In this paper, we describe the categorization task, which focused on the classification of full-text documents, simulating the task of curators of the Mouse Genome Informatics (MGI) system and consisting of three subtasks. One subtask of the categorization task required the triage of articles likely to have experimental evidence warranting the assignment of GO terms, while the other two subtasks were concerned with the assignment of the three top-level GO categories to each paper containing evidence for these categories. RESULTS: The track had 33 participating groups. The mean and maximum utility measure for the triage subtask was 0.3303, with a top score of 0.6512. No system was able to substantially improve results over simply using the MeSH term Mice. Analysis of significant feature overlap between the training and test sets was found to be less than expected. Sample coverage of GO terms assigned to papers in the collection was very sparse. Determining papers containing GO term evidence will likely need to be treated as separate tasks for each concept represented in GO, and therefore require much denser sampling than was available in the data sets. The annotation subtask had a mean F-measure of 0.3824, with a top score of 0.5611. The mean F-measure for the annotation plus evidence codes subtask was 0.3676, with a top score of 0.4224. Gene name recognition was found to be of benefit for this task. CONCLUSION: Automated classification of documents for GO annotation is a challenging task, as was the automated extraction of GO code hierarchies and evidence codes. However, automating these tasks would provide substantial benefit to biomedical curation, and therefore work in this area must continue. Additional experience will allow comparison and further analysis about which algorithmic features are most useful in biomedical document classification, and better understanding of the task characteristics that make automated classification feasible and useful for biomedical document curation. The TREC Genomics Track will be continuing in 2005 focusing on a wider range of triage tasks and improving results from 2004

    Evaluation of the electronic long cane: improving mobility in urban environments

    Get PDF
    A wide range of portable and wearable electronic travel aids have been developed to enable visually impaired people to move around public spaces without a sighted guide. However, few of them have gone beyond the prototype stage and the long cane and guide dog are still the main mobility aids. Despite the importance of evaluation to determine, for instance, effective functioning and end-user satisfaction, a standard approach has not yet been developed for mobility aids. The paper reports the evaluation of a low-cost electronic long cane, developed by the authors and colleagues in Brazil. It used a two-part methodology involving an experimental investigation of performance of the electronic long cane and a questionnaire to explore user satisfaction. The results of the experiments and questionnaire demonstrated both the cane’s usefulness and the need for modifications to improve its functioning. This work is also important for the development of methodologies for effective evaluation, as this is the first evaluation of a mobility device developed and carried out in Brazil. In addition, it is one of only a small number of evaluations in real locations with real obstacles. Finally, a series of recommendations for evaluating mobility devices is presented. What this paper adds? A standard approach to evaluating electronic travel for visually impaired people has not yet been developed and the most appropriate approach may depend on the objectives of the evaluation. Existing approaches generally use participants with no previous experience of using the device being evaluated and is carried out indoors with artificial obstacles. The training or device familiarisation period usually provided might be insufficient for participants to obtain optimal device performance or an effective comparison to be made of different devices. The approach to evaluating an electronic long cane reported in this paper has three main advantages over previous methods. The participants were experienced users of the electronic long cane who had been using it to support their daily mobility for at least a month. The evaluation was carried out in two different real urban environments with real obstacles. This has the advantages of being close to real-life cane use and participants being able to make informed comments and suggestions for improvements as a result of their experience. A questionnaire included questions on user satisfaction with and evaluation of a number of different cane features based on their experiences of cane use over a period. The work is also significant as the first detailed mobility device evaluation carried out in Brazil and in the presentation of a series of recommendations divided into themes for effective evaluation of mobility devices

    A stimulus to define informatics and health information technology

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Despite the growing interest by leaders, policy makers, and others, the terminology of health information technology as well as biomedical and health informatics is poorly understood and not even agreed upon by academics and professionals in the field.</p> <p>Discussion</p> <p>The paper, presented as a Debate to encourage further discussion and disagreement, provides definitions of the major terminology used in biomedical and health informatics and health information technology. For informatics, it focuses on the words that modify the term as well as individuals who practice the discipline. Other categories of related terms are covered as well, from the associated disciplines of computer science, information technolog and health information management to the major application categories of applications used. The discussion closes with a classification of individuals who work in the largest segment of the field, namely clinical informatics.</p> <p>Summary</p> <p>The goal of presenting in Debate format is to provide a starting point for discussion to reach a documented consensus on the definition and use of these terms.</p

    Topological terms with qubit regularization and relativistic quantum circuits

    Full text link
    Qubit regularization provides a rich framework to explore quantum field theories. The freedom to choose how the important symmetries of the theory are embedded in the qubit regularization scheme allows us to construct new lattice models with rich phase diagrams. Some of the phases can contain topological terms which lead to critical phases. In this work we introduce and study the SU(3)-F qubit regularization scheme to embed the SO(3) spin-symmetry. We argue that qubit models in this regularization scheme contain several phases including a critical phase which describes the k = 1 Wess-Zumino-Witten (WZW) conformal field theory (CFT) at long distances, and two massive phases one of which is trvially gapped and the other which breaks the lattice translation symmetry. We construct a simple space-time Euclidean lattice model with a single coupling U and study it using the Monte Carlo method. We show the model has a critical phase at small U and a trivially massive phase at large U with a first order transition separating the two. Another feature of our model is that it is symmetric under space-time rotations, which means the temporal and spatial lattice spacing are connected to each other. The unitary time evolution operator obtained by a Wick rotation of the transfer matrix of our model can help us compute the physics of the k = 1 WZW CFT in real time without the need for tuning the temporal lattice spacing to zero. We use this idea to introduce the concept of a relativistic quantum circuit on a discrete space-time lattice.Comment: 15 page

    Advancing Biomedical Image Retrieval: Development and Analysis of a Test Collection

    Get PDF
    Objective: Develop and analyze results from an image retrieval test collection. Methods: After participating research groups obtained and assessed results from their systems in the image retrieval task of Cross-Language Evaluation Forum, we assessed the results for common themes and trends. In addition to overall performance, results were analyzed on the basis of topic categories (those most amenable to visual, textual, or mixed approaches) and run categories (those employing queries entered by automated or manual means as well as those using visual, textual, or mixed indexing and retrieval methods). We also assessed results on the different topics and compared the impact of duplicate relevance judgments. Results: A total of 13 research groups participated. Analysis was limited to the best run submitted by each group in each run category. The best results were obtained by systems that combined visual and textual methods. There was substantial variation in performance across topics. Systems employing textual methods were more resilient to visually oriented topics than those using visual methods were to textually oriented topics. The primary performance measure of mean average precision (MAP) was not necessarily associated with other measures, including those possibly more pertinent to real users, such as precision at 10 or 30 images. Conclusions: We developed a test collection amenable to assessing visual and textual methods for image retrieval. Future work must focus on how varying topic and run types affect retrieval performance. Users' studies also are necessary to determine the best measures for evaluating the efficacy of image retrieval system

    The MERG Suite: Tools for discovering competencies and associated learning resources

    Get PDF
    This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
    • …
    corecore