1,146 research outputs found

    A method to implement fine-grained access control for personal health records through standard relational database queries

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    AbstractOnline personal health records (PHRs) enable patients to access, manage, and share certain of their own health information electronically. This capability creates the need for precise access-controls mechanisms that restrict the sharing of data to that intended by the patient. The authors describe the design and implementation of an access-control mechanism for PHR repositories that is modeled on the eXtensible Access Control Markup Language (XACML) standard, but intended to reduce the cognitive and computational complexity of XACML. The authors implemented the mechanism entirely in a relational database system using ANSI-standard SQL statements. Based on a set of access-control rules encoded as relational table rows, the mechanism determines via a single SQL query whether a user who accesses patient data from a specific application is authorized to perform a requested operation on a specified data object. Testing of this query on a moderately large database has demonstrated execution times consistently below 100ms. The authors include the details of the implementation, including algorithms, examples, and a test database as Supplementary materials

    Maximizing Audibility and Speech Recognition with Non-Linear Frequency Compression by Estimating Audible Bandwidth

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    Objective—Nonlinear frequency compression attempts to restore high-frequency audibility by lowering high-frequency input signals. Methods of determining the optimal parameters that maximize speech understanding have not been evaluated. The effect of maximizing the audible bandwidth on speech recognition for a group of listeners with normal hearing is described. Design—Nonword recognition was measured with twenty normal-hearing adults. Three audiograms with different high-frequency thresholds were used to create conditions with varying high-frequency audibility. Bandwidth was manipulated using three conditions for each audiogram: conventional processing, the manufacturer’s default compression parameters, and compression parameters that optimized bandwidth. Results—Nonlinear frequency compression optimized to provide the widest audible bandwidth improved nonword recognition compared to both conventional processing and the default parameters. Conclusion—These results showed that using the widest audible bandwidth maximized speech identification when using nonlinear frequency compression. Future studies should apply these methods to listeners with hearing loss to demonstrate efficacy in clinical populations

    Norovirus Epidemiology and Duration of Shedding in Michigan, 2007-2008

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    Background: In the United States, an estimated 23 million cases of norovirus (NoV) are reported each year, and although mortality is low, the morbidity and economic impact are substantial. Methods: RT-PCR and sequencing were used for identification of NoV genotypes obtained from outbreak and sporadic cases. RT Quant PCR was used to determine the viral load in fecal specimens. In order to rule out bacterial infection as the cause for acute gastroenteritis (AGE), bacterial culture for Salmonella, E.coli O157, Shigella, Campylobacter and Clostridium difficile was performed by standard laboratory procedures. The duration of NV shedding was investigated with longitudinal sampling in the sporadic cases and an evaluation of the association between viral load and days since clinical onset in the outbreak-associated cases. Results: We describe the epidemiology and strain identification for NoV circulating in Michigan during 2007-8 in concurrent sporadic and outbreak-associated cases. In 2007- 8, 138 norovirus outbreaks (3,437 cases) were reported to the MDCH. Among the 47 outbreak specimens sequenced, GI was identified in 14 (29.8%) and GII in 33 (70.2%). The predominant type was GII.4, found in 23 of the 33 (69.6%) GII specimens. The statistical analysis of outbreak-associated cases showed that neither NoV type nor number of days post-onset were associated with NoV log concentration. Among the sporadic cases, the repeated measures analysis of variance showed that NoV type (I or II) was not associated with log titer (P = 0.90), but that the number of weeks post-onset was statistically associated with declining log titer at p = 0.0005. Conclusion: We found no predominant strain difference between concurrent sporadic and outbreak-associated cases. Prevalent strains of NoV were shed in high concentration for at least two weeks past disease onset, suggesting that current public health recommendations for 2-3 days home isolation following clinical recovery may need to be lengthened
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