24 research outputs found
Time periodicity and dynamical stability in two-boson systems
We calculate the period of recurrence of dynamical systems comprising two
interacting bosons. A number of theoretical issues related to this problem are
discussed, in particular, the conditions for small periodicity. The knowledge
gathered in this way is then used to propose a notion of dynamical stability
based on the stability of the period. Dynamical simulations show good agreement
with the proposed scheme. We also apply the results to the phenomenon known as
coherent population trapping and find stability conditions in this specific
case.Comment: 7+ pages, 5 figure
Information Discovery on Electronic Health Records Using Authority Flow Techniques
<p>Abstract</p> <p>Background</p> <p>As the use of electronic health records (EHRs) becomes more widespread, so does the need to search and provide effective information discovery within them. Querying by keyword has emerged as one of the most effective paradigms for searching. Most work in this area is based on traditional Information Retrieval (IR) techniques, where each document is compared individually against the query. We compare the effectiveness of two fundamentally different techniques for keyword search of EHRs.</p> <p>Methods</p> <p>We built two ranking systems. The traditional BM25 system exploits the EHRs' content without regard to association among entities within. The Clinical ObjectRank (CO) system exploits the entities' associations in EHRs using an authority-flow algorithm to discover the most relevant entities. BM25 and CO were deployed on an EHR dataset of the cardiovascular division of Miami Children's Hospital. Using sequences of keywords as queries, sensitivity and specificity were measured by two physicians for a set of 11 queries related to congenital cardiac disease.</p> <p>Results</p> <p>Our pilot evaluation showed that CO outperforms BM25 in terms of sensitivity (65% vs. 38%) by 71% on average, while maintaining the specificity (64% vs. 61%). The evaluation was done by two physicians.</p> <p>Conclusions</p> <p>Authority-flow techniques can greatly improve the detection of relevant information in EHRs and hence deserve further study.</p